WorldWideScience

Sample records for herbaceous ecosystem measurements

  1. Ecosystem-atmosphere exchange of CO2 in a temperate herbaceous peatland in the Sanjiang Plain of northeast China

    Science.gov (United States)

    Zhu, Xiaoyan; Song, Changchun; Swarzenski, Christopher M.; Guo, Yuedong; Zhang, Xinhow; Wang, Jiaoyue

    2015-01-01

    Northern peatlands contain a considerable share of the terrestrial carbon pool, which will be affected by future climatic variability. Using the static chamber technique, we investigated ecosystem respiration and soil respiration over two growing seasons (2012 and 2013) in a Carex lasiocarpa-dominated peatland in the Sanjiang Plain in China. We synchronously monitored the environmental factors controlling CO2 fluxes. Ecosystem respiration during these two growing seasons ranged from 33.3 to 506.7 mg CO2–C m−2 h−1. Through step-wise regression, variations in soil temperature at 10 cm depth alone explained 73.7% of the observed variance in log10(ER). The mean Q10 values ranged from 2.1 to 2.9 depending on the choice of depth where soil temperature was measured. The Q10 value at the 10 cm depth (2.9) appears to be a good representation for herbaceous peatland in the Sanjiang Plain when applying field-estimation based Q10values to current terrestrial ecosystem models due to the most optimized regression coefficient (63.2%). Soil respiration amounted to 57% of ecosystem respiration and played a major role in peatland carbon balance in our study. Emphasis on ecosystem respiration from temperate peatlands in the Sanjiang Plain will improve our basic understanding of carbon exchange between peatland ecosystem and the atmosphere.

  2. Fast-cycling unit of root turnover in perennial herbaceous plants in a cold temperate ecosystem

    Science.gov (United States)

    Sun, Kai; Luke McCormack, M.; Li, Le; Ma, Zeqing; Guo, Dali

    2016-01-01

    Roots of perennial plants have both persistent portion and fast-cycling units represented by different levels of branching. In woody species, the distal nonwoody branch orders as a unit are born and die together relatively rapidly (within 1–2 years). However, whether the fast-cycling units also exist in perennial herbs is unknown. We monitored root demography of seven perennial herbs over two years in a cold temperate ecosystem and we classified the largest roots on the root collar or rhizome as basal roots, and associated finer laterals as secondary, tertiary and quaternary roots. Parallel to woody plants in which distal root orders form a fast-cycling module, basal root and its finer laterals also represent a fast-cycling module in herbaceous plants. Within this module, basal roots had a lifespan of 0.5–2 years and represented 62–87% of total root biomass, thus dominating annual root turnover (60%–81% of the total). Moreover, root traits including root length, tissue density, and biomass were useful predictors of root lifespan. We conclude that both herbaceous and woody plants have fast-cycling modular units and future studies identifying the fast-cycling module across plant species should allow better understanding of how root construction and turnover are linked to whole-plant strategies.

  3. Impact of herbaceous understory vegetation to ecosystem water cycle, productivity and infiltration in a semi arid oak woodland assessed by stable oxygen isotopes

    Science.gov (United States)

    Dubbert, Maren; Piayda, Arndt; Silva, Filipe Costa e.; Correia, Alexandra C.; Pereira, Joao S.; Cuntz, Matthias; Werner, Christiane

    2015-04-01

    vegetation strongly increased rain infiltration, specifically during strong rain events. In conclusion, beneficial understory vegetation effects were dominant. However, the observed vulnerability of the understory vegetation to drought and competition for water with trees suggests, that increased drought and altered precipitation pattern as predicted in future climate change scenarios for the Mediterranean basin not only threaten understory development. They also very likely decrease rain infiltration and ground water recharge by decreasing understory vegetation cover and increasing amount of heavy precipitation events with high run-off from sealed bare soils. This in turn can severely diminish cork-oak productivity and hence the resilience of the ecosystem toward drought (Costa e Silva et al., in rev.). Dubbert, M; Cuntz, M; Piayda, A; Maguas, C; Werner, C: Partitioning evapotranspiration - Testing the Craig and Gordon model with field measurements of oxygen isotope ratios of evaporative fluxes. J Hydrol (2013) Dubbert, M; Piayda, A; Cuntz, M; Correia, AC; Costa e Silva, F; Pereira, JS; Werner, C: Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange, Frontiers in Plant Science (2014a) Dubbert, M; Mosena, A; Piayda, A; Cuntz, M; Correia, AC; Pereira, JS; Werner, C: Influence of tree cover on herbaceous layer development and carbon and water fluxes in a Portuguese cork oak woodland., Acta Oecologica

  4. Communities of endophytic sebacinales associated with roots of herbaceous plants in agricultural and grassland ecosystems are dominated by Serendipita herbamans sp. nov.

    Directory of Open Access Journals (Sweden)

    Kai Riess

    Full Text Available Endophytic fungi are known to be commonly associated with herbaceous plants, however, there are few studies focusing on their occurrence and distribution in plant roots from ecosystems with different land uses. To explore the phylogenetic diversity and community structure of Sebacinales endophytes from agricultural and grassland habitats under different land uses, we analysed the roots of herbaceous plants using strain isolation, polymerase chain reaction (PCR, transmission electron microscopy (TEM and co-cultivation experiments. A new sebacinoid strain named Serendipita herbamans belonging to Sebacinales group B was isolated from the roots of Bistorta vivipara, which is characterized by colourless monilioid cells (chlamydospores that become yellow with age. This species was very common and widely distributed in association with a broad spectrum of herbaceous plant families in diverse habitats, independent of land use type. Ultrastructurally, the presence of S. herbamans was detected in the cortical cells of Plantago media, Potentilla anserina and Triticum aestivum. In addition, 13 few frequent molecular operational taxonomic units (MOTUs or species were found across agricultural and grassland habitats, which did not exhibit a distinctive phylogenetic structure. Laboratory-based assays indicate that S. herbamans has the ability to colonize fine roots and stimulate plant growth. Although endophytic Sebacinales are widely distributed across agricultural and grassland habitats, TEM and nested PCR analyses reinforce the observation that these microorganisms are present in low quantity in plant roots, with no evidence of host specificity.

  5. Upper Carboniferous herbaceous lycopsids

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, B.A. [University of Wales, Cardigan (United Kingdom). Dept. of Geography

    1997-01-01

    Herbaceous lycopsids are often overlooked in palaeobotanical studies because of problems of morphological interpretation and identification. The literature on Euramerican Upper Carboniferous herbaceous lycopsids is reviewed on those species referred to the genera Selaginellites, Lycopodites, Paurodendron, Carinostrobus, Miadesmia, Spencerites and the identification of some specimens is challenged. The stratigraphical range of these lycopsids and those of dispersed spores referable to them are also reviewed and suggestions are given for the relatively late appearance of many of these lycopsids in the Euramerican Coal Measures swamps. It is suggested that anisophyllous Selaginella-like lycopsids made their first appearance in the Bolsovian (ex Westphalian C) of the Saar-Lorraine intramontane basin. Evidence from studies of coal balls and dispersed spore assemblages confirm that herbaceous lycopsids were most abundantly present in open-moor communities. Certain species of these herbaceous lycopsids, the Selaginella-like ones, are included within the extant genus Selaginella Linnaeus. For this reason a number of new combinations are proposed.

  6. Do agrometeorological data improve optical satellite-based estimations of the herbaceous yield in Sahelian semi-arid ecosystems?

    DEFF Research Database (Denmark)

    Diouf, Abdoul Aziz; Hiernaux, Pierre; Brandt, Martin Stefan;

    2016-01-01

    Quantitative estimates of forage availability at the end of the growing season in rangelands are helpful for pastoral livestock managers and for local, national and regional stakeholders in natural resource management. For this reason, remote sensing data such as the Fraction of Absorbed Photosyn......Quantitative estimates of forage availability at the end of the growing season in rangelands are helpful for pastoral livestock managers and for local, national and regional stakeholders in natural resource management. For this reason, remote sensing data such as the Fraction of Absorbed...... evapotranspiration satellite gridded data to estimate the annual herbaceous yield in the semi-arid areas of Senegal. It showed that a machine-learning model combining FAPAR seasonal metrics with various agrometeorological data provided better estimations of the in situ annual herbaceous yield (R2 = 0.69; RMSE = 483...

  7. Stability measures in arid ecosystems

    Science.gov (United States)

    Nosshi, M. I.; Brunsell, N. A.; Koerner, S.

    2015-12-01

    Stability, the capacity of ecosystems to persist in the face of change, has proven its relevance as a fundamental component of ecological theory. Here, we would like to explore meaningful and quantifiable metrics to define stability, with a focus on highly variable arid and semi-arid savanna ecosystems. Recognizing the importance of a characteristic timescale to any definition of stability, our metrics will be focused scales from annual to multi-annual, capturing different aspects of stability. Our three measures of stability, in increasing order of temporal scale, are: (1) Ecosystem resistance, quantified as the degree to which the system maintains its mean state in response to a perturbation (drought), based on inter-annual variability in Normalized Difference Vegetation Index (NDVI). (2) An optimization approach, relevant to arid systems with pulse dynamics, that models vegetation structure and function based on a trade off between the ability to respond to resource availability and avoid stress. (3) Community resilience, measured as species turnover rate (β diversity). Understanding the nature of stability in structurally-diverse arid ecosystems, which are highly variable, yields theoretical insight which has practical implications.

  8. Evapotranspiration Modeling and Measurements at Ecosystem Level

    Science.gov (United States)

    Sirca, C.; Snyder, R. L.; Mereu, S.; Kovács-Láng, E.; Ónodi, G.; Spano, D.

    2012-12-01

    In recent years, the availability of reference evapotranspiration (ETo) data is greatly increased. ETo, in conjunction with coefficients accounting for the difference between the vegetation and the reference surface, provides estimation of the actual evapotranspiration (ETa). The coefficients approach was applied in the past mainly for crops, due the lack of experimental data and difficulties to account for terrain and vegetation variability in natural ecosystems. Moreover, the assessment of ETa over large spatial scale by measurements is often time consuming, and requires several measurement points with relatively expensive and sophisticated instrumentation and techniques (e.g. eddy covariance). The Ecosystem Water Program (ECOWAT) was recently developed to help estimates of ETa of ecosystems by accounting for microclimate, vegetation type, plant density, and water stress. ETa on natural and semi-natural ecosystems has several applications, e.g. water status assessment, fire danger estimation, and ecosystem management practices. In this work, results obtained using ECOWAT to assess ETa of a forest ecosystem located in Hungary are reported. The site is a part of the EU-FP7 INCREASE project, which aims to study the effects of climate change on European shrubland ecosystems. In the site, a climate manipulation experiment was setted up to have a warming and a drought treatment (besides the control). Each treatment was replicated three times We show how the ECOWAT model performed when the predicted actual evapotranspiration is compared with actual evapotranspiration obtained from Surface Renewal method and with soil moisture measurements. ECOWAT was able to capture the differences in the water balance at treatment level, confirming its potential as a tool for water status assessment. For the Surface Renewal method, high frequency temperature data were collected to estimate the sensible heat flux (H'). The net radiation (Rn) and soil heat flux density (G) were also

  9. Quality Measures for Digital Business Ecosystems Formation

    Science.gov (United States)

    Raza, Muhammad; Hussain, Farookh Khadeer; Chang, Elizabeth

    To execute a complex business task, business entities may need to collaborate with each other as individually they may not have the capability or willingness to perform the task on its own. Such collaboration can be seen implemented in digital business ecosystems in the form of simple coalitions using multi-agent systems or by employing Electronic Institutions. A major challenge is choosing optimal partners who will deliver the agreed commitments, and act in the coalition’s interest. Business entities are scaled according to their quality level. Determining the quality of previously unknown business entities and predicting the quality of such an entity in a dynamic environment are crucial issues in Business Ecosystems. A comprehensive quality management system grounded in the concepts of Trust and Reputation can help address these issues.

  10. Biogeochemical cycling in terrestrial ecosystems - Modeling, measurement, and remote sensing

    Science.gov (United States)

    Peterson, D. L.; Matson, P. A.; Lawless, J. G.; Aber, J. D.; Vitousek, P. M.

    1985-01-01

    The use of modeling, remote sensing, and measurements to characterize the pathways and to measure the rate of biogeochemical cycling in forest ecosystems is described. The application of the process-level model to predict processes in intact forests and ecosystems response to disturbance is examined. The selection of research areas from contrasting climate regimes and sites having a fertility gradient in that regime is discussed, and the sites studied are listed. The use of remote sensing in determining leaf area index and canopy biochemistry is analyzed. Nitrous oxide emission is investigated by using a gas measurement instrument. Future research projects, which include studying the influence of changes on nutrient cycling in ecosystems and the effect of pollutants on the ecosystems, are discussed.

  11. Dryland degradation: Measurement and effects on ecosystems

    Science.gov (United States)

    Noojipady, P.; Prince, S. D.; Rishmawi, K.

    2012-12-01

    Land degradation is frequently described as a global crisis, affecting large areas globally and large numbers of people. Nevertheless, the location and severity of degradation globally with a resolution relevant to human activities is unknown. Beyond the direct stress of degradation on human livelihoods, there are important effects on the physical and biological environment. Examples include loss of potential primary production, changes in the surface water and energy balances, erosion, sediment transport and lofting of dust aerosols. Globally , degradation is mainly associated with drylands, such as the US dustbowl of the 1930s and, supposedly, ongoing loss of crop and livestock production in desert margins on all continents. The alarm over loss of land to deserts, particularly early 1980s in the African Sahel, led to the adoption of the term "desertification". Such degradation is said to have two components; a physical environment that reduces productivity; and human land use that exceeds the resilience of the land. Ecological theory suggests that land can exist in multiple stable states with transitions between them. Some experimental evidence suggests that one such state is degradation from which there can be no recovery. Clearly the occurrence of such stable degradation, where land is unable to recover when the physical conditions such as rainfall and human land use are ameliorated, is of theoretical and practical importance. The aim of this work is to contribute to the resolution of two issues: (i) are there significant areas in which land has been degraded by human actions and, (ii), have any of these areas entered a stable degraded state? Detection of the human component necessarily requires control of the physical component of degradation. We have developed a technique to detect areas that are at their potential production and to assess other areas relative to these. Satellite measurements of vegetation indices are used as a surrogate for Net Primary

  12. The ICOS Ecosystem protocol for gas concentration measurements

    Science.gov (United States)

    Aubinet, Marc; Papale, Dario

    2014-05-01

    This research was initiated in the frame of the ICOS Ecosystem Thematic Center. The aim of ICOS is to provide long term high precision observations required to understand the present state and to predict future behavior of the global carbon cycle and greenhouse gas emissions. Observations will be made through high precision network of stations measuring greenhouse gas fluxes from ecosystems and oceans and greenhouse gas concentrations in the atmosphere. In a long term monitoring infrastructure like the ICOS Ecosystem network, it is crucial to ensure maximum comparability between sites and, for this reason, it is strongly suggested to highly standardize methods and sensors where the knowledge about systematic and random differences between different approaches is not yet fully known, in particular in the medium-long term time range. Long term measurements of trace gas fluxes exchanged by ecosystem require the use of the eddy covariance technique for which gas analyzers are, similarly to sonic anemometers, key elements. However, neither an international standard nor a list of requisites for sensors does exist yet. This presentation focuses thus on the protocol for high frequency gas concentration using infrared gas analyzers. It results from discussions that were brought among the Working group on Eddy covariance fluxes and Storage measurements established by the ICOS Ecosystem Thematic Center and implied about 70 scientists and field workers. The protocol includes a definition of the variable and of the measurement method (infrared gas analyzer), instructions concerning the system conditioning (gas sampling system description including pump, tube, filter dimensioning), sensor calibration and maintenance and finally required data format.

  13. Measurement of undisturbed di-nitrogen emissions from aquatic ecosystems

    Science.gov (United States)

    Qin, Shuping, Clough, Timothy, Lou, Jiafa; Hu, Chunsheng; Oenema, Oene; Wrage-Mönnig, Nicole; Zhang, Yuming

    2016-04-01

    Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) during the last century has greatly contributed to increased food production1-4. However, enriching the biosphere with Nr through N fertilizer production, combustion, and biological N2 fixation has also caused a series of negative effects on global ecosystems 5,6, especially aquatic ecosystems7. The main pathway converting Nr back into the atmospheric N2 pool is the last step of the denitrification process, i.e., the reduction of nitrous oxide (N2O) into N2 by micro-organisms7,8. Despite several attempts9,10, there is not yet an accurate, fast and direct method for measuring undisturbed N2 fluxes from denitrification in aquatic sediments at the field scale11-14. Such a method is essential to study the feedback of aquatic ecosystems to Nr inputs1,2,7. Here we show that the measurement of both N2O emission and its isotope signature can be used to infer the undisturbed N2 fluxes from aquatic ecosystems. The microbial reduction of N2O increases the natural abundance of 15N-N2O relative to 14N-N2O (δ15N-N2O). We observed linear relationships between δ15N-N2O and the logarithmic transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the undisturbed N2 flux from aquatic ecosystems can be inferred from measurements of N2O emissions and the δ15N-N2O signature. Our method allows the determination of field-scale N2 fluxes from undisturbed aquatic ecosystems, and thereby allows model predictions of denitrification rates to be tested. The undisturbed N2 fluxes observed are almost one order of magnitude higher than those estimated by the traditional method, where perturbation of the system occurs, indicating that the ability of aquatic ecosystems to remove Nr may have been severely underestimated.

  14. Biochemical methane potential and anaerobic biodegradability of non-herbaceous and herbaceous phytomass in biogas production

    DEFF Research Database (Denmark)

    Triolo, Jin Mi; Pedersen, Lene; Qu, Haiyan

    2012-01-01

    The suitability of municipal plant waste for anaerobic digestion was examined using 57 different herbaceous and non-herbaceous samples. Biochemical methane potential (BMP) and anaerobic biodegradability were related to the degree of lignification and crystallinity of cellulose. The BMP of herbace...

  15. Biochemical methane potential and anaerobic biodegradability of non-herbaceous and herbaceous phytomass in biogas production

    DEFF Research Database (Denmark)

    Triolo, Jin Mi; Pedersen, Lene; Qu, Haiyan;

    2012-01-01

    of herbaceous garden plants (332.7 CH4 NL kg VS1) was high, although lower than that of energy crops (400–475 CH4 NL kg VS1). Herbaceous wild plants from natural grassland contained most lignocelluloses, leading to relatively low BMP (214.0 CH4 NL kg VS1). Non-herbaceous phytomass had a high degree...

  16. Measuring and Modeling the U.S. Regulatory Ecosystem

    Science.gov (United States)

    Bommarito, Michael J., II; Katz, Daniel Martin

    2017-07-01

    Over the last 23 years, the U.S. Securities and Exchange Commission has required over 34,000 companies to file over 165,000 annual reports. These reports, the so-called "Form 10-Ks," contain a characterization of a company's financial performance and its risks, including the regulatory environment in which a company operates. In this paper, we analyze over 4.5 million references to U.S. Federal Acts and Agencies contained within these reports to measure the regulatory ecosystem, in which companies are organisms inhabiting a regulatory environment. While individuals across the political, economic, and academic world frequently refer to trends in this regulatory ecosystem, far less attention has been paid to supporting such claims with large-scale, longitudinal data. In this paper, in addition to positing a model of regulatory ecosystems, we document an increase in the regulatory energy per filing, i.e., a warming "temperature." We also find that the diversity of the regulatory ecosystem has been increasing over the past two decades. These findings support the claim that regulatory activity and complexity are increasing, and this framework contributes an important step towards improving academic and policy discussions around legal complexity and regulation.

  17. Measuring and Modeling the U.S. Regulatory Ecosystem

    Science.gov (United States)

    Bommarito, Michael J., II; Katz, Daniel Martin

    2017-09-01

    Over the last 23 years, the U.S. Securities and Exchange Commission has required over 34,000 companies to file over 165,000 annual reports. These reports, the so-called "Form 10-Ks," contain a characterization of a company's financial performance and its risks, including the regulatory environment in which a company operates. In this paper, we analyze over 4.5 million references to U.S. Federal Acts and Agencies contained within these reports to measure the regulatory ecosystem, in which companies are organisms inhabiting a regulatory environment. While individuals across the political, economic, and academic world frequently refer to trends in this regulatory ecosystem, far less attention has been paid to supporting such claims with large-scale, longitudinal data. In this paper, in addition to positing a model of regulatory ecosystems, we document an increase in the regulatory energy per filing, i.e., a warming "temperature." We also find that the diversity of the regulatory ecosystem has been increasing over the past two decades. These findings support the claim that regulatory activity and complexity are increasing, and this framework contributes an important step towards improving academic and policy discussions around legal complexity and regulation.

  18. BVOC ecosystem flux measurements at a high latitude wetland site

    Directory of Open Access Journals (Sweden)

    T. Holst

    2008-12-01

    Full Text Available In this study, we present summertime concentrations and fluxes of biogenic volatile organic compounds (BVOCs measured at a sub-arctic wetland in northern Sweden using a disjunct eddy-covariance (DEC technique based on a proton transfer reaction mass spectrometer (PTR-MS. The vegetation at the site was dominated by Sphagnum, Carex and Eriophorum spp. The performance of the DEC system was assessed by comparing H3O+-ion cluster formed with water molecules (H3O+(H2O at m37 with water vapour concentration measurements made using an adjacent humidity sensor, and from a comparison of sensible heat fluxes for high frequency and DEC data obtained from the sonic anemometer. These analyses showed no significant PTR-MS sensor drift over a period of several weeks and only a small flux-loss due to high-frequency spectrum omissions. This loss was within the range expected from other studies and the theoretical considerations.

    Standardised (20°C and 1000 μmol m−2 s−1 PAR summer isoprene emission rates of 323 μg C m−2 (ground area h−1 were comparable with findings from more southern boreal forests, and fen-like ecosystems. On a diel scale, measured fluxes indicated a stronger temperature dependence when compared with emissions from temperate or (subtropical ecosystems. For the first time, to our knowledge, we report ecosystem methanol fluxes from a sub-arctic ecosystem. Maximum daytime emission fluxes were around 270 μg m−2 h−1 (ca. 100 μg C m−2 h-1 and measurements indicated some nocturnal deposition.

    The measurements reported here covered a period of 50 days (1 August to 19 September 2006, approximately one half of the growing season at the site, and allowed to investigate the effect of vegetation senescence on daily BVOC fluxes and on their temperature and light

  19. BVOC ecosystem flux measurements at a high latitude wetland site

    Directory of Open Access Journals (Sweden)

    T. Holst

    2010-02-01

    Full Text Available In this study, we present summertime concentrations and fluxes of biogenic volatile organic compounds (BVOCs measured at a sub-arctic wetland in northern Sweden using a disjunct eddy-covariance (DEC technique based on a proton transfer reaction mass spectrometer (PTR-MS. The vegetation at the site was dominated by Sphagnum, Carex and extit{Eriophorum} spp. The measurements reported here cover a period of 50 days (1 August to 19 September 2006, approximately one half of the growing season at the site, and allowed to investigate the effect of day-to-day variation in weather as well as of vegetation senescence on daily BVOC fluxes, and on their temperature and light responses. The sensitivity drift of the DEC system was assessed by comparing H3O+-ion cluster formed with water molecules (H3O+(H2O at m37 with water vapour concentration measurements made using an adjacent humidity sensor, and the applicability of the DEC method was analysed by a comparison of sensible heat fluxes for high frequency and DEC data obtained from the sonic anemometer. These analyses showed no significant PTR-MS sensor drift over a period of several weeks and only a small flux-loss due to high-frequency spectrum omissions. This loss was within the range expected from other studies and the theoretical considerations.

    Standardised (20 °C and 1000 μmol m−2 s−1 PAR summer isoprene emission rates found in this study of 329 μg C m−2 (ground area h−1 were comparable with findings from more southern boreal forests, and fen-like ecosystems. On a diel scale, measured fluxes indicated a stronger temperature dependence than emissions from temperate or (subtropical ecosystems. For the first time, to our knowledge, we report ecosystem methanol fluxes from a sub-arctic ecosystem. Maximum daytime emission fluxes were around 270 μg m−2 h−1

  20. How to misinterpret photosynthesis measurements and develop incorrect ecosystem models

    Science.gov (United States)

    Prentice, Iain Colin

    2017-04-01

    It is becoming widely accepted than current land ecosystem models (dynamic global vegetation models and land-surface models) rest on shaky foundations and are in need of rebuilding, taking advantage of huge data resources that were hardly conceivable when these models were first developed. It has also become almost a truism that next-generation model development should involve observationalists, experimentalists and modellers working more closely together. What is currently lacking, however, is open discussion of specific problems in the structure of current models, and how they might have arisen. Such a discussion is important if the same mistakes are not to be perpetuated in a new generation of models. I will focus on the central processes governing leaf-level gas exchange, which powers the land carbon and water cycles. I will show that a broad area of confusion exists - as much in the empirical ecophysiological literature as in modelling research - concerning the interpretation of gas-exchange measurements and (especially) their scaling up from the narrow temporal and spatial scales of laboratory measurements to the broad-scale research questions linked to global environmental change. In particular, I will provide examples (drawing on a variety of published and unpublished observations) that illustrate the benefits of taking a "plant-centred" view, showing how consideration of optimal acclimation challenges many (often untstated) assumptions about the relationship of plant and ecosystem processes to environmental variation. (1) Photosynthesis is usually measured at light saturation (implying Rubisco limitation), leading to temperature and CO2 responses that are completely different from those of gross primary production (GPP) under field conditions. (2) The actual rate of electron transport under field conditions depends strongly on the intrinsic quantum efficiency, which is temperature-independent (within a broad range) and unrelated to the maximum electron

  1. Understanding and Improving the Smartphone Ecosystem: Measurements, Security and Tools

    OpenAIRE

    Wei, Xuetao

    2013-01-01

    The smartphone ecosystem encompasses smartphones' hardware and software platform, applications (apps) running on top of the platform, as well the infrastructural components. As the smartphone ecosystem is becoming an important part of our daily life, it is essential to profile, understand and, ultimately, secure the devices and the information they collect and manipulate. To this end, we pave the way for understanding and improving the smartphone ecosystem by designing useful tools, performin...

  2. Towards reconstructing herbaceous biome dynamics and associated precipitation in Africa: insights from the classification of grass morphological traits

    Science.gov (United States)

    Pasturel, Marine; Alexandre, Anne; Novello, Alice; Moctar Dieye, Amadou; Wele, Abdoulaye; Paradis, Laure; Hely, Christelle

    2014-05-01

    Inter-tropical herbaceous ecosystems occupy a 1/5th of terrestrial surface, a half of the African continent, and are expected to extend in the next decades. Dynamic of these ecosystems is simulated with poor accuracy by Dynamic Global Vegetation Models (DGVMs). One of the bias results from the fact that the diversity of the grass layer dominating these herbaceous ecosystems is poorly taken into account. Mean annual precipitation and the length of the dry season are the main constrains of the dynamics of these ecosystems. Conversely, changes in vegetation affect the water cycle. Inaccuracy in herbaceous ecosystem simulation thus impacts simulations of the water cycle (including precipitation) and vice versa. In order to increase our knowledge of the relationships between grass morphological traits, taxonomy, biomes and climatic niches in Western and South Africa, a 3-step methodology was followed: i) values of culm height, leaf length and width of dominant grass species from Senegal were gathered from flora and clustered using the Partition Around Medoids (PAM) method; ii) trait group ability to sign climatic domains and biomes was assessed using Kruskal-Wallis tests; iii) genericity and robustness of the trait groups were evaluated through their application to Chadian and South African botanical datasets. Results show that 8 grass trait groups are present either in Senegal, Chad or South Africa. These 8 trait groups are distributed along mean annual precipitation and dry season length gradients. The combination of three of them allow to discriminate mean annual precipitation domains (1000 mm) and herbaceous biomes (steppes, savannas, South African grasslands and Nama-Karoo). With these results in hand, grass Plant Functional Types (PFTs) of the DGMV LPJ-GUESS will be re-parameterized and particular attention will be given to the herbaceous biomass assigned to each grass trait group. Simultaneously, relationships between grass trait groups and phytolith vegetation

  3. Hippopotamus (H. amphibius) diet change indicates herbaceous plant encroachment following megaherbivore population collapse

    Science.gov (United States)

    Chritz, Kendra L.; Blumenthal, Scott A.; Cerling, Thure E.; Klingel, Hans

    2016-01-01

    Megaherbivores (>1000 kg) are critical for ecosystem health and function, but face population collapse and extinction globally. The future of these megaherbivore-impoverished ecosystems is difficult to predict, though many studies have demonstrated increasing representation of C3 woody plants. These studies rely on direct observational data, however, and tools for assessing decadal-scale changes in African ecology without observation are lacking. We use isotopic records of historical common hippopotamus (Hippopotamus amphibius) canines to quantify herbaceous vegetation change in Queen Elizabeth National Park, Uganda following a period of civil unrest and poaching. This poaching event led to population collapse of two threatened African megaherbivore species: hippopotamus and African elephants (Loxodonta africana). Serial carbon isotope ratios (δ13C) in canine enamel from individuals that lived between 1960–2000 indicated substantial increases in C3 herbaceous plants in their diet (<20% C3 in the 1960s to 30–45% C3 in the 80s and 90s), supported by other observational and ecological data. These data indicate megaherbivore loss results in succession of both woody and herbaceous C3 vegetation and further reaching effects, such as decreased grazing capacity and herbivore biodiversity in the area. Given multiple lines of evidence, these individuals appear to accurately capture herbaceous vegetation change in Mweya. PMID:27616433

  4. Hippopotamus (H. amphibius) diet change indicates herbaceous plant encroachment following megaherbivore population collapse.

    Science.gov (United States)

    Chritz, Kendra L; Blumenthal, Scott A; Cerling, Thure E; Klingel, Hans

    2016-01-01

    Megaherbivores (>1000 kg) are critical for ecosystem health and function, but face population collapse and extinction globally. The future of these megaherbivore-impoverished ecosystems is difficult to predict, though many studies have demonstrated increasing representation of C3 woody plants. These studies rely on direct observational data, however, and tools for assessing decadal-scale changes in African ecology without observation are lacking. We use isotopic records of historical common hippopotamus (Hippopotamus amphibius) canines to quantify herbaceous vegetation change in Queen Elizabeth National Park, Uganda following a period of civil unrest and poaching. This poaching event led to population collapse of two threatened African megaherbivore species: hippopotamus and African elephants (Loxodonta africana). Serial carbon isotope ratios (δ(13)C) in canine enamel from individuals that lived between 1960-2000 indicated substantial increases in C3 herbaceous plants in their diet (<20% C3 in the 1960s to 30-45% C3 in the 80s and 90s), supported by other observational and ecological data. These data indicate megaherbivore loss results in succession of both woody and herbaceous C3 vegetation and further reaching effects, such as decreased grazing capacity and herbivore biodiversity in the area. Given multiple lines of evidence, these individuals appear to accurately capture herbaceous vegetation change in Mweya.

  5. Relative Radiosensitivities of Woody and Herbaceous Spermatophytes.

    Science.gov (United States)

    Sparrow, R C; Sparrow, A H

    1965-03-19

    The sensitivities of several woody and herbaceous species to single acute exposures to cobalt-60 gamma rays have been determined. Within each group the sensitivity of each species is largely determined by its average interphase chromosome volume (interphase nuclear volume divided by chromosome number) of shoot apical meristem cells. On the basis of the calculated amounts of energy absorbed (in kiloelectron volts) per interphase chromosome at an exposure necessary to produce a given biological effect, woody species were approximately twice as sensitive as herbaceous species.

  6. Toward coordinated space-based air quality, carbon cycle, and ecosystem measurements to quantify air quality-ecosystem interactions

    Science.gov (United States)

    Neu, J. L.; Schimel, D.; Lerdau, M.; Drewry, D.; Fu, D.; Payne, V.; Bowman, K. W.; Worden, J. R.

    2016-12-01

    Tropospheric ozone concentrations are increasing in many regions of the world, and this ozone can severely damage vegetation. Ozone enters plants through their stomata and oxidizes tissues, inhibiting physiology and decreasing ecosystem productivity. Ozone has been experimentally shown to reduce crop production, with important implications for global food security as concentrations rise. Ozone damage to forests also alters productivity and carbon storage and may drive changes in species distributions and biodiversity. Process-based quantitative estimates of these ozone impacts on terrestrial ecosystems at continental to global scales as well as of feedbacks to air quality via production of volatile organic compounds (VOCs) are thus crucial to sustainable development planning. We demonstrate that leveraging planned and proposed missions to measure ozone, formaldehyde, and isoprene along with solar-induced fluorescence (SiF), evapotranspiration, and plant nitrogen content can meet the requirements of an integrated observing system for air quality-ecosystem interactions while also meeting the needs of the individual Air Quality, Carbon Cycle, and Ecosystems communities.

  7. Suggestions on management measures of pine forest ecosystems invaded by Bursaphelenchus xylophilus

    Institute of Scientific and Technical Information of China (English)

    SHI Juan; LUO You-qing; XIA Nai-bin; WU Hai-wei; SONG Ji-ying

    2008-01-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion,we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme "Prevention is priority, but integrated with curative techniques and ecological resilience" on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosystems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way.

  8. Degraded Ecosystem and its Rehabilitating Measures in Sandy Areas of North China

    Institute of Scientific and Technical Information of China (English)

    ZHANGFengchun; LUQi

    2004-01-01

    Ecosystem degradation occurs in parallel with desertification process in sandy areas of North China. The vast sandy areas in North China are characterized with flexible environments and fragile ecosystems as well as intensive human activities. Due to the annual precipitation gradient decreases from east to west in North China, the whole sandy region falls into 3 main climatic zones: add, semi-add and dry sub-humid zones.The ecosystems in each type of climatic zones are different in climatic conditions, human activities,cultural dimensions, vegetation covers, landscapes, and causes and processes of ecosystem degradation.Therefore, the most effective rehabilitation measures of degraded ecosystems in different types of the climatic zones are also different. For the arid sandy areas, vegetation rehabilitation of degraded ecosystems needs to be completely closed, assisting with artificial measures, such as plantation, irrigation or others. For semi-add sandy areas, the effective measures of vegetation rehabilitation of degraded ecosystems include increasing of proportion of forests and rangelands and limitation of reclamation; reducing the carrying capacity of livestock on unit area of rangelands and growth of fodder plants; and plantation on the lowlands betweens and dunes. For the dry sub-humid areas, the most effective measure is enclosure of degraded ecosystems combined with plantation, and in some cases, just stop uses by grazing or reclamation.

  9. Multiyear Multiseasonal Changes in Leaf and Canopy Traits Measured by AVIRIS over Ecosystems with Different Functional Type Characteristics Through the Progressive California Drought 2013-2015

    Science.gov (United States)

    Ustin, S.; Roth, K. L.; Huesca, M.; Casas, A.; Adeline, K.; Drewry, D.; Koltunov, A.; Ramirez, C.

    2015-12-01

    Given the known heterogeneity in ecological processes within plant communities in California, we questioned whether the concept of conventional plant functional types (cPFTs) was adequate to characterize the functionality of the dominant species in these communities. We examined seasonal (spring, summer, fall) airborne AVIRIS and MASTER imagery collected during three years of progressive drought in California, and airborne LiDAR acquired once, for ecosystems that represent a wide range of plant functional types, from annual agriculture and herbaceous perennial wetlands, to forests and shrublands, including broadleaf deciduous and evergreen species and conifer species. These data were used to determine the extent to which changes in canopy chemistry could be detected, quantified, and related to leaf and canopy traits that are indicators of physiological functioning (water content, Leaf Mass Area, total C, N, and pigments (chlorophyll a, b, and carotenoids). At the canopy scale we measured leaf area index, and for forests — species, height, canopy area, DBH, deciduous or evergreen, broadleaf or needleleaf, and gap size. Strong correlations between leaf and canopy traits were predictable and quantifiable from spectroscopy data. Key structural properties of canopy height, biomass and complexity, a measure of spatial and vertical heterogeneity, were predicted by AVIRIS and validated against LiDAR data. Our data supports the hypothesis that optical sensors provide more detailed information about the distribution and variability in leaf and canopy traits related to plant functionality than cPFTs.

  10. The important role of scattered trees on the herbaceous diversity of a grazed Mediterranean dehesa

    Science.gov (United States)

    López-Sánchez, Aida; San Miguel, Alfonso; López-Carrasco, Celia; Huntsinger, Lynn; Roig, Sonia

    2016-10-01

    Scattered trees are considered keystone structures and play an important role in Mediterranean sylvopastoral systems. Such systems are associated with high biodiversity and provide important natural resources and ecosystem services. In this study, we measured the contribution of scattered trees and different grazing management (cattle, sheep and wildlife only) to the diversity of the grassland sward in a dehesa (open holm oak woodland) located in Central Spain. We analyzed alpha and beta diversity through measurement of species richness, Shannon-Wiener, and Whittaker indices, respectively; and the floristic composition of the herb layer using subplots within two adjacent plots (trees present vs. trees absent) under three different grazing management regimes, including wildlife only, during a year. We found a 20-30% increment in the alpha diversity of wooded plots, compared to those without trees, regardless of grazing management. All beta indices calculated showed more than 60% species turnover. Wooded plots were occupied by different herbaceous species in different heterogeneous microsites (under the canopy, in the ecotone or on open land) created by the trees. Livestock grazing modified species composition (e.g. more nitrophilous species) compared to wildlife only plots. In addition to all their other benefits, trees are important to maintaining grassland diversity in Mediterranean dehesas.

  11. Assessing net ecosystem carbon exchange of U S terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Qianlai [Purdue University; Law, Beverly E. [Oregon State University; Baldocchi, Dennis [University of California, Berkeley; Ma, Siyan [University of California, Berkeley; Chen, Jiquan [University of Toledo, Toledo, OH; Richardson, Andrew [Harvard University; Melillo, Jerry [Marine Biological Laboratory; Davis, Ken J. [Pennsylvania State University; Hollinger, D. [USDA Forest Service; Wharton, Sonia [University of California, Davis; Falk, Matthias [University of California, Davis; Paw, U. Kyaw Tha [University of California, Davis; Oren, Ram [Duke University; Katulk, Gabriel G. [Duke University; Noormets, Asko [North Carolina State University; Fischer, Marc [Lawrence Berkeley National Laboratory (LBNL); Verma, Shashi [University of Nebraska; Suyker, A. E. [University of Nebraska, Lincoln; Cook, David R. [Argonne National Laboratory (ANL); Sun, G. [USDA Forest Service; McNulty, Steven G. [USDA Forest Service; Wofsy, Steve [Harvard University; Bolstad, Paul V [University of Minnesota; Burns, Sean [University of Colorado, Boulder; Monson, Russell K. [University of Colorado, Boulder; Curtis, Peter [Ohio State University, The, Columbus; Drake, Bert G. [Smithsonian Environmental Research Center, Edgewater, MD; Foster, David R. [Harvard University; Gu, Lianhong [ORNL; Hadley, Julian L. [Harvard University; Litvak, Marcy [University of New Mexico, Albuquerque; Martin, Timothy A. [University of Florida, Gainesville; Matamala, Roser [Argonne National Laboratory (ANL); Meyers, Tilden [NOAA, Oak Ridge, TN; Oechel, Walter C. [San Diego State University; Schmid, H. P. [Indiana University; Scott, Russell L. [USDA ARS; Torn, Margaret S. [Lawrence Berkeley National Laboratory (LBNL)

    2011-01-01

    More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr 1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr 1 over the period 2001 2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by 20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.

  12. Hippopotamus (H. amphibius) diet change indicates herbaceous plant encroachment following megaherbivore population collapse

    Science.gov (United States)

    Chritz, Kendra L.; Blumenthal, Scott A.; Cerling, Thure E.; Klingel, Hans

    2016-09-01

    Megaherbivores (>1000 kg) are critical for ecosystem health and function, but face population collapse and extinction globally. The future of these megaherbivore-impoverished ecosystems is difficult to predict, though many studies have demonstrated increasing representation of C3 woody plants. These studies rely on direct observational data, however, and tools for assessing decadal-scale changes in African ecology without observation are lacking. We use isotopic records of historical common hippopotamus (Hippopotamus amphibius) canines to quantify herbaceous vegetation change in Queen Elizabeth National Park, Uganda following a period of civil unrest and poaching. This poaching event led to population collapse of two threatened African megaherbivore species: hippopotamus and African elephants (Loxodonta africana). Serial carbon isotope ratios (δ13C) in canine enamel from individuals that lived between 1960–2000 indicated substantial increases in C3 herbaceous plants in their diet (biodiversity in the area. Given multiple lines of evidence, these individuals appear to accurately capture herbaceous vegetation change in Mweya.

  13. Grass and herbaceous plants for biomass

    Energy Technology Data Exchange (ETDEWEB)

    Prine, G.M.; Mislevy, P.

    1983-01-01

    Florida has little fossil fuel resources, but the state does have an adequate climate for high plant biomass production. Grasses and herbaceous plants are renewable resources which could furnish a portion of Florida's energy needs. Dry matter yields of various annual and perennial grasses and herbaceous plants which can be grown in Florida are presented in this paper. Residues of crops already being grown for other reasons would be an economical source of biomass. The best alternative for an energy crop appears to be tropical perennial shrub-like legumes and tall, strong-stemmed grasses that have their top growth killed by frosts each winter and that regrow annually from below-ground regenerative plant parts. Napiergrass or elephantgrass (Pennisetum purpureum L.), leucaena (Leucaena leucocephala (Lam.) de Wit) and sugarcane (Saccharum spp.) are examples of such energy plants. Napiergrass (PI 300086) had dry matter yields when cut once at the end of the season of 44.5 and 52.4 Mg/ha in 1981 and 1982 respectively, at Gainesville, Fla. and 56.7 Mg/ha for the first season after planting (1982) at Ona, Fla. A dry matter yield of 73 Mg/ha was obtained from a 10-year-old clump of leucaena at Gainesville in 1981. However, research needs to be conducted on methods of harvesting and storing biomass plants to be used for energy. Napiergrass and other grasses may be solar dried standing after a freeze or following cutting in the fall and then be rolled into large bales for storage in the open or crude shelters. A year-round supply of economical biomass must be available before grasses and herbaceous plants are widely grown and used for energy purposes. 6 references.

  14. Evaluating subsoiling and herbaceous weed control on shortleaf pine planted in retired farm land

    Science.gov (United States)

    John D. Kushla

    2010-01-01

    In March 2005, shortleaf pine was planted on retired fields of the Mississippi Agriculture and Forestry Experiment Station in Holly Springs. The objectives were to evaluate subsoiling and herbaceous weed control on first year seedling stocking, survival, and size. First year seedling measurements were made on stocking, survival, and size. Only results for first year...

  15. Herbaceous response to type and severity of disturbance

    Science.gov (United States)

    Katherine J. Elliott; Craig A. Harper; Beverly Collins

    2011-01-01

    The herbaceous layer varies with topographic heterogeneity and harbors the great majority of plant diversity in eastern deciduous forests. We described the interplay between disturbances, both natural and human-caused, and composition, dynamics, and diversity of herbaceous vegetation, especially those in early successional habitats. Management actions that create low...

  16. On the coupled use of sapflow and eddy covariance measurements: environmental impacts on the evapotranspiration of an heterogeneous - wild olives based - Sardinian ecosystem.

    Science.gov (United States)

    Curreli, Matteo; Corona, Roberto; Montaldo, Nicola; Oren, Ram

    2015-04-01

    Sapflow and eddy covariance techniques are attractive methods for evapotranspiration (ET) estimates. We demonstrated that in Mediterranean ecosystems, characterized by an heterogeneous spatial distribution of different plant functional types (PFT) such as grass and trees, the combined use of these techniques becomes essential for the actual ET estimates. Indeed, during the dry summers these water-limited heterogeneous ecosystems are typically characterized by a simple dual PFT system with strong-resistant woody vegetation and bare soil, since grass died. An eddy covariance - micrometeorological tower has been installed over an heterogeneous ecosystem at the Orroli site in Sardinia (Italy) from 2003. The site landscape is a mixture of Mediterranean patchy vegetation types: wild olives, different shrubs and herbaceous species, which died during the summer. Where patchy land cover leads and the surface fluxes from different cover are largely different, ET evaluation may be not robust enough and eddy covariance method hypothesis are not anymore preserved. In these conditions the sapflow measurements, performed by thermodissipation probes, provide robust estimates of the transpiration from woody vegetation. Through the coupled use of the sapflow sensor observations, a 2D footprint model of the eddy covariance tower and high resolution satellite images for the estimate of the foot print land cover map, the eddy covariance measurements can be correctly interpreted, and ET components (bare soil evaporation and woody vegetation transpiration) can be separated. Based on the Granier technique, 33 thermo-dissipation probes have been built and 6 power regulators have been assembled to provide a constant current of 3V to the sensors. The sensors have been installed at the Orroli site into 15 wild olives clumps with different characteristics in terms of tree size, exposition to wind and solar radiation and soil depth. The sap flow sensors outputs are analyzed to estimate

  17. Soil properties and understory herbaceous biomass in forests of three species of Quercus in Northeast Portugal

    Directory of Open Access Journals (Sweden)

    Marina Castro

    2014-12-01

    Full Text Available Aim of study: This paper aims to characterize some soil properties within the first 25 cm of the soil profile and the herbaceous biomass in Quercus forests, and the possible relationships between soil properties and understory standing biomass.Area of study: Three monoespecific Quercus forests (Q. suber L., Q. ilex subsp. rotundifolia Lam. and Q. pyrenaica Willd in NE Portugal.Material and methods: During 1999 and 2000 soil properties (pH-KCl, total soil nitrogen (N, soil organic carbon (SOC, C/N ratio, available phosphorus (P, and available potassium (K and herbaceous biomass production of three forest types: Quercus suber L., Quercus ilex subsp. rotundifolia Lam. and Quercus pyrenaica Willd were studied.Main results: The results showed a different pattern of soil fertility (N, SOC, P, K in Quercus forests in NE of Portugal. The C/N ratio and the herbaceous biomass confirmed this pattern. Research highlights: There is a pattern of Quercus sp. distribution that correlates with different soil characteristics by soil characteristics in NE Portugal. Q. pyrenaica ecosystems were found in more favoured areas (mesic conditions; Q. rotundifolia developed in nutrient-poor soils (oligotrophic conditions; and Q. suber were found in intermediate zones.Keywords: fertility; biomass; C/N ratio; cork oak; holm oak; pyrenean oak.

  18. Measurement of ecological capital of Chinese terrestrial ecosystem based on remote sensing

    Institute of Scientific and Technical Information of China (English)

    PAN; Yaozhong; SHI; Peijun; ZHU; Wenquan; GU; Xiaohe; FAN

    2005-01-01

    The biosphere of the Earth is essential to human survival and development. The services of ecosystems are critical to the functioning of the Earth's life-support system. They contribute to human welfare both directly and indirectly. Ecological capital refers to the sum of the direct biological resources value and the indirect ecosystem services value. It is necessary to estimate the ecological capital in order to bring it to the society and market economic system, and draw the social attention to ecological environment constructions. An estimation model for ecological capital based on remote sensing is presented in this paper. The parameters in the model are quantitatively measured using NOAA/AVHRR and other ancillary data, including the land cover types, the vegetation coverage, and the vegetation net primary productivity (NPP) of terrestrial ecosystem. Based on the economic parameters in previously published studies and a few original calculations, the annual ecological capital of the entire terrestrial ecosystem of China is quantitatively estimated at 6.44 trillion (1012) yuan (RMB), and the spatial distribution of the ecological capital is also analyzed. Traditional ecological methods to ecological capital measurement are based on homogeneous plot scales, and the regional scaling is a key problem in their applications. As the proposed remote sensing approach, it provides a new method to ecological capital measurement completely based on observation data. It can not only overcome the regional scaling problem easily, but also allows the ecological capital to be estimated objectively and spatial-explicitly.

  19. Satellite remote sensing of rangelands in Botswana. II - NOAA AVHRR and herbaceous vegetation

    Science.gov (United States)

    Prince, S. D.; Tucker, C. J.

    1986-01-01

    The relation between the normalized difference vegetation index (NDVI) and the herbaceous vegetation in Tamasane, Shakwe, and Masama in eastern Botswana is studied using 1983-1984 AVHRR data. The procedures for Landsat MSS interpolation of ground measurements and the data processing of the AVHRR data are described. The temporal sequence AVHRR global-area coverage (GAC) composite NDVI is examined. The AVHRR GAC composite NDVI and biomass and Landsat MSS interpolations of field measurements are analyzed and compared.

  20. Continuous In-situ Measurements of Carbonyl Sulfide to Constrain Ecosystem Carbon and Water Exchange

    Science.gov (United States)

    Rastogi, B.; Kim, Y.; Berkelhammer, M. B.; Noone, D. C.; Lai, C. T.; Hollinger, D. Y.; Bible, K.; Leen, J. B.; Gupta, M.; Still, C. J.

    2014-12-01

    Understanding the processes that control the terrestrial exchange of carbon and water are critical for examining the role of forested ecosystems in changing climates. A small but increasing number of studies have identified Carbonyl Sulfide (OCS) as a potential tracer for photosynthesis. OCS is hydrolyzed by an irreversible reaction in leaf mesophyll cells that is catalyzed by the enzyme, carbonic anhydrase. Leaf-level field and greenhouse studies indicate that OCS uptake is controlled by stomatal activity and that the ratio of OCS and CO2 uptake is reasonably constant. Existing studies on ecosystem OCS exchange have been based on laboratory measurements or short field campaigns and therefore little information on OCS exchange in a natural ecosystem over longer timescales is available. The objective of this study is to further assess the stability of OCS as a tracer for canopy photosynthesis in an active forested ecosystem and also to assess its utility for constraining transpiration, since both fluxes are mediated by canopy stomatal conductance. An off-axis integrated cavity output spectroscopy analyzer (Los Gatos Research Inc.) was deployed at the Wind River Experimental Forest in Washington (45.8205°N, 121.9519°W). Canopy air was sampled from three heights to measure vertical gradients of OCS within the canopy, and OCS exchange between the forest and the atmosphere. Here we take advantage of simultaneous measurements of the stable isotopologues of H2O and CO2 at corresponding heights as well as NEE (Net Ecosystem Exchange) from eddy covariance measurements to compare GPP (Gross Primary Production) and transpiration estimates from a variety of independent techniques. Our findings seek to allow assessment of the environmental and ecophysicological controls on evapotranspiration rates, which are projected to change in coming decades, and are otherwise poorly constrained.

  1. Woody-Herbaceous Species Coexistence in Mulga Hillslopes: Modelling Structure and Function

    Science.gov (United States)

    Soltanjalili, M. J.; Saco, P. M.; Willgoose, G. R.

    2016-12-01

    The fundamental processes underlying the coexistence of woody and herbaceous species in arid and semi-arid areas have been a topic of intense research during the last few decades. Experimental and modelling studies have both supported and disputed alternative hypotheses explaining this phenomenon. Vegetation models including the key processes that drive coexistence can be used to understand vegetation pattern dynamics and structure under current climate conditions, and to predict changes under future conditions. Here we present work done towards linking the observations to modelling. The model captures woody-herbaceous coexistence along a rainfall gradient characteristic of typical conditions on Mulga ecosystems in Australia. The dynamic vegetation model simulates the spatial dynamics of overland flow, soil moisture and vegetation growth of two species. It incorporates key mechanisms for coexistence and pattern formation, including facilitation by evaporation reduction through shading, and infiltration feedbacks, local and non-local seed dispersal, competition for water uptake. Model outcomes, obtained including diflerent mechanisms, are qualitatively compared to typical vegetation cover patterns in the Australian Mulga bioregion where bush fire is very infrequent and the fate of vegetation cover is mostly determined by intra- and interspecies interactions. Through these comparisons, and by drawing on the large number of recent studies that have delivered new insights into the dynamics of such ecosystems, we identify main mechanisms that need an improved representation in the dynamic vegetation models. We show that a realistic parameterization of the model leads to results which are aligned with the observations reported in the literature. At the lower end of the rainfall gradient woody species coexist with herbaceous species within a sparse banded pattern, while at higher rainfall woody species tend to dominate the landscape.

  2. Is the interaction between Retama sphaerocarpa and its understorey herbaceous vegetation always reciprocally positive? Competition?facilitation shift during Retama establishment

    Science.gov (United States)

    Espigares, Tíscar; López-Pintor, Antonio; Rey Benayas, José M.

    2004-10-01

    Retama sphaerocarpa is a Mediterranean shrub that when adult, facilitates the establishment of herbaceous plants under its canopy. We test the hypothesis that during the establishment of R. sphaerocarpa seedlings, the interaction with the herbaceous plants is negative. We carried out a greenhouse experiment in which seedlings of R. sphaerocarpa were grown under different conditions of competition with herbs, watering and date of emergence. Measurements of seedling mortality, biomass and growth were taken during the first growing season. We found a significant relationship between R. sphaerocarpa seedling mortality and competition in early spring, presumably due to higher water demand of herbaceous plants. Generally, presence of herbaceous species, lower availability of water and late emergence had negative effects on biomass and growth of Retama seedlings. Additional water compensated for the negative effects of competition, except on leaves and cladodes of Retama seedlings, suggesting that other resources, such as light, could be the subject of competition. In contrast, Retama seedlings exerted a positive influence on the herbaceous plants by increasing their survival and biomass, probably as a consequence of the high availability of nutrients provided by the Rhizobia nodules in the roots of Retama seedlings. We concluded that, at the regeneration stage of the shrub, the interaction between the herbaceous vegetation and the shrub is negative for the shrub and positive for the herbs. This suggests a shift from competition to facilitation with age of Retama, as reciprocal positive interactions have been described between herbaceous plants and adult individuals of the shrub.

  3. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    Science.gov (United States)

    Roales, Javier; Durán, Jorge; Bechtold, Heather A; Groffman, Peter M; Rosi-Marshall, Emma J

    2013-01-01

    Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT) and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

  4. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    Directory of Open Access Journals (Sweden)

    Javier Roales

    Full Text Available Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

  5. Relationship between Species Diversity of Herbaceous Plants in the Shelterbelt and Environment Factors%防护林下草本植物层片物种多样性与环境因子的关系

    Institute of Scientific and Technical Information of China (English)

    张佳; 李生宇; 靳正忠; 雷加强

    2011-01-01

    Many researchers have focused on the close relationship between species diversity and ecosystem stability. The Taklimakan Desert is a mobile desert with various dunes. Climate in the desert is characterized by the extreme aridity, low vegetation coverage and a few survival salt-tolerant desert plants. So, herbaceous plants grow only in the bottom of dunes under the conditions of high temperature, drought and high saline environment. As the longest desert highway in the world, the Tarim Desert Highway in Xinjiang of China is 436 km in length and covers an area of 3 128 hm2. The shelterbelt along the highway with average width of 2 - 6 km is irrigated with salty groundwater. Shrubs of the shelterbelt are Haloxylon, Tamarix and Calligonum plants. Herbaceous plant species have been notably increased since the shelterbelt was planted, and the herbaceous plant coverage has been over 40% along some highway sections. A stable windbreak and sand-fixation system has been formed by the shrub layer and herbaceous plant layer. Previous researches focused on sand-fixing efficiency, micro-climate benefits, physical and chemical properties of soil, changes of plant growth and transpiration along the shelterbelt in the Taklimakan Desert. To date, there are no the papers focusing on the change of species diversity of the artificial ecosystem yet.In this paper, the spatial differentiation ofherbaceous plants is researched, and the relationship between species diversity and environmental factors is analyzed. In the study, 10 sample plots were delimited along the Tarim Desert Highway shelterbelt, 3 sample lines, 100 m in length and perpendicular to the highway, were set in each sample plot, and 10 to 14 sub-plots (5 m ×5 m) were delimited between the sample lines. Number, coverage and richness of herbaceous plants and corresponding environment factors, such as groundwater level, groundwater electrical conductivity and mineralization, soil electrical conductivity, average range of

  6. Abundance of introduced species at home predicts abundance away in herbaceous communities

    Science.gov (United States)

    Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  7. EUROSPEC: at the interface between remote sensing and ecosystem CO2 flux measurements in Europe

    Directory of Open Access Journals (Sweden)

    A. Porcar-Castell

    2015-08-01

    Full Text Available Resolving the spatial and temporal dynamics of gross primary productivity (GPP of terrestrial ecosystems across different scales remains a challenge. Remote sensing is regarded as the solution to upscale point observations conducted at the ecosystem level, using the eddy covariance (EC technique, to the landscape and global levels. In addition to traditional vegetation indices, the photochemical reflectance index (PRI and the emission of solar-induced chlorophyll fluorescence (SIF, now measurable from space, provide a new range of opportunities to monitor the global carbon cycle using remote sensing. However, the scale mismatch between EC observations and the much coarser satellite-derived data complicates the integration of the two sources of data. The solution is to establish a network of in situ spectral measurements that can act as bridge between EC measurements and remote sensing data. In situ spectral measurements have been already conducted for many years at EC sites, but using variable instrumentation, setups, and measurement standards. In Europe in particular, in situ spectral measurements remain highly heterogeneous. The goal of EUROSPEC Cost Action ES0930 was to promote the development of common measuring protocols and new instruments towards establishing best practices and standardization of in situ spectral measurements. In this review we describe the background and main tradeoffs of in situ spectral measurements, review the main results of EUROSPEC Cost Action, and discuss the future challenges and opportunities of in situ spectral measurements for improved estimation of local and global carbon cycle.

  8. [Emergy evaluation and dynamic measurement analysis of agro-ecosystems in Sichuan Province of Southwest China].

    Science.gov (United States)

    Zhang, Ying-Cong; Du, Shou-Hu

    2012-03-01

    Agro-ecosystem is the most basic system for human beings survival, while the analysis of the structure and function of the system is the key to solve the problems of agro-ecological environment. In this paper, emergy theory and related economic measurement methods including data envelopment analysis, cointegration test, and error correction model were applied to quantitatively analyze the operation dynamics, environmental loading, operation efficiency, and input-output relation of the agro-ecosystems in Sichuan Province and its 21 cities in 1997-2009. In the study period, Sichuan Province was in the transition period from traditional agriculture to modern agriculture. The agricultural mechanization level of the Province improved constantly, resources utilization efficiency enhanced continually, overall structural dominant degree was better, but the over-reliance on economic emergy input caused the sustainability of the system weakened gradually. The development status of the agro-ecosystems in the Province varied among regions. Chengdu Plain and Western Sichuan Highland were either in overexploited or in underutilized, while the hilly areas were full of vitality and development potential, tended to be the important areas for the future development of Sichuan agriculture. Generally, the operation efficiency of the agro-ecosystems in the Province was relatively low, with the situation differed in different regions due to the lower technical efficiency or improper scale. There was a long-term equilibrium between the economic emergy indices and output emergy, but the short-term emergy input didn't reach the ideal output.

  9. Measuring conditions and trends in ecosystem services at multiple scales: the Southern African Millennium Ecosystem Assessment (SAfMA) experience

    Science.gov (United States)

    van Jaarsveld, A.S; Biggs, R; Scholes, R.J; Bohensky, E; Reyers, B; Lynam, T; Musvoto, C; Fabricius, C

    2005-01-01

    The Southern African Millennium Ecosystem Assessment (SAfMA) evaluated the relationships between ecosystem services and human well-being at multiple scales, ranging from local through to sub-continental. Trends in ecosystem services (fresh water, food, fuel-wood, cultural and biodiversity) over the period 1990–2000 were mixed across scales. Freshwater resources appear strained across the continent with large numbers of people not securing adequate supplies, especially of good quality water. This translates to high infant mortality patterns across the region. In some areas, the use of water resources for irrigated agriculture and urban–industrial expansion is taking place at considerable cost to the quality and quantity of freshwater available to ecosystems and for domestic use. Staple cereal production across the region has increased but was outstripped by population growth while protein malnutrition is on the rise. The much-anticipated wood-fuel crisis on the subcontinent has not materialized but some areas are experiencing shortages while numerous others remain vulnerable. Cultural benefits of biodiversity are considerable, though hard to quantify or track over time. Biodiversity resources remain at reasonable levels, but are declining faster than reflected in species extinction rates and appear highly sensitive to land-use decisions. The SAfMA sub-global assessment provided an opportunity to experiment with innovative ways to assess ecosystem services including the use of supply–demand surfaces, service sources and sink areas, priority areas for service provision, service ‘hotspots’ and trade-off assessments. PMID:15814355

  10. Native herbaceous plant species with potential use in phytoremediation of heavy metals, spotlight on wetlands - A review.

    Science.gov (United States)

    Oyuela Leguizamo, Mayerly Alexandra; Fernández Gómez, Wilmar Darío; Sarmiento, Martha Cecilia Gutiérrez

    2017-02-01

    Soil, air and water pollution caused by the mobility and solubility of heavy metals significantly damages the environment, human health, plants and animals. One common in situ method used for the decontamination of heavy metals is phytoremediation. This usually involves the use of exotic species. However, these species may exhibit invasive behavior, thereby, affect the environmental and ecological dynamics of the ecosystem into which they are introduced. This paper focuses on some native herbaceous plant species reported on the wetlands of Bogota, Colombia, with potential use in phytoremediation of heavy metals. To do that, the authors identified and searched a bibliography based on key words related to heavy metal decontamination. In addition, authors gathered and analyzed relevant information that allowed the comprehension of the phytoremediation process. This paper suggests the study of 41 native or endemic species regarding their behavior towards heavy metal contamination. From a survey of herbaceous plants reported in Bogota, native and endemic species that belong to predominant families in heavy metal accumulation processes were selected. Although found in Colombian's wetlands, these can also be found worldwide. Therefore, they are of great interest due to their global presence and their potential for use in phytoremediation. The current research about the development of phytoremediation focuses on the identification of new herbaceous species able to decontaminate substratum polluted with heavy metals to contribute with the investigation of the ecology and environment of the nature's remnants in urban wetland ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Impacts of nitrogen deposition on herbaceous ground flora and epiphytic foliose lichen species in southern Ontario hardwood forests.

    Science.gov (United States)

    McDonough, Andrew M; Watmough, Shaun A

    2015-01-01

    In this study 70 sugar maple (Acer saccharum Marsh.) dominated plots in Ontario, Canada were sampled in the spring of 2009 and 2010 and herbaceous plant and epiphytic foliose lichen species data were compared against modeled N and S deposition data, climate parameters and measured soil and plant/lichen S and N concentration. Herbaceous plant species richness was positively correlated with temperature and indices of diversity (Shannon Weiner and Simpson's Index) were positively correlated with soil pH but not N or S deposition or standardized foliar N scores. Herbaceous community composition was strongly controlled by traditional factors, but there was a small and significant influence of atmospheric S and N deposition. Epiphytic lichen species richness exhibited a strong negative relationship with standardized foliar N score and only one lichen species (Phaeophyscia rubropulchra) was observed at sites with a standardized foliar N score of 0.76.

  12. Lake and wetland ecosystem services measuring water storage and local climate regulation

    Science.gov (United States)

    Wong, Christina P.; Jiang, Bo; Bohn, Theodore J.; Lee, Kai N.; Lettenmaier, Dennis P.; Ma, Dongchun; Ouyang, Zhiyun

    2017-04-01

    Developing interdisciplinary methods to measure ecosystem services is a scientific priority, however, progress remains slow in part because we lack ecological production functions (EPFs) to quantitatively link ecohydrological processes to human benefits. In this study, we tested a new approach, combining a process-based model with regression models, to create EPFs to evaluate water storage and local climate regulation from a green infrastructure project on the Yongding River in Beijing, China. Seven artificial lakes and wetlands were established to improve local water storage and human comfort; evapotranspiration (ET) regulates both services. Managers want to minimize the trade-off between water losses and cooling to sustain water supplies while lowering the heat index (HI) to improve human comfort. We selected human benefit indicators using water storage targets and Beijing's HI, and the Variable Infiltration Capacity model to determine the change in ET from the new ecosystems. We created EPFs to quantify the ecosystem services as marginal values [Δfinal ecosystem service/Δecohydrological process]: (1) Δwater loss (lake evaporation/volume)/Δdepth and (2) Δsummer HI/ΔET. We estimate the new ecosystems increased local ET by 0.7 mm/d (20.3 W/m2) on the Yongding River. However, ET rates are causing water storage shortfalls while producing no improvements in human comfort. The shallow lakes/wetlands are vulnerable to drying when inflow rates fluctuate, low depths lead to higher evaporative losses, causing water storage shortfalls with minimal cooling effects. We recommend managers make the lakes deeper to increase water storage, and plant shade trees to improve human comfort in the parks.

  13. Effects of Re-vegetation on Herbaceous Species Composition and Biological Soil Crusts Development in a Coal Mine Dumping Site.

    Science.gov (United States)

    Zhao, Yang; Zhang, Peng; Hu, Yigang; Huang, Lei

    2016-02-01

    Despite the critical roles of plant species' diversity and biological soil crusts (BSCs) in arid and semi-arid ecosystems, the restoration of the diversity of herbaceous species and BSCs are rarely discussed during the process of vegetation restoration of anthropogenically damaged areas in these regions. In this study, the herbaceous plant species composition, along with the BSCs coverage and thicknesses, was investigated at six different re-vegetation type sites, and the natural vegetation site of the Heidaigou open pit coal mine in China's Inner Mongolia Autonomous Region was used as a reference. The highest total species richness (16), as well as the species richness (4.4), occurred in the Tree and Herbaceous vegetation type site. The species composition similarities between the restored sites and the reference site were shown to be very low, and ranged from 0.09 to 0.42. Also, among the restored sites, the similarities of the species were fairly high and similar, and ranged from 0.45 to 0.93. The density and height of the re-vegetated woody plants were significantly correlated with the indexes of the diversity of the species. The Shrub vegetation type site showed the greatest total coverage (80%) of BSCs and algae crust coverage (48%). The Shrub and Herbaceous type had the greatest thicknesses of BSCs, with as much as 3.06 mm observed, which was followed by 2.64 mm for the Shrub type. There was a significant correlation observed between the coverage of the total BSCs, and the total vegetation and herbaceous vegetation coverage, as well as between the algae crust coverage and the herbaceous vegetation coverage. It has been suggested that the re-vegetated dwarf woody plant species (such as shrubs and semi-shrubs) should be chosen for the optimal methods of the restoration of herbaceous species diversity at dumping sites, and these should be planted with low density. Furthermore, the effects of vegetation coverage on the colonization and development the BSCs

  14. An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements

    Directory of Open Access Journals (Sweden)

    G. Wohlfahrt

    2015-01-01

    Full Text Available Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of living plants as the major source and the reaction with OH as the major sink of methanol, global methanol budgets diverge considerably in terms of source/sink estimates reflecting uncertainties in the approaches used to model, and the empirical data used to separately constrain these terms. Here we compiled micrometeorological methanol flux data from eight different study sites and reviewed the corresponding literature in order to provide a first cross-site synthesis of the terrestrial ecosystem-scale methanol exchange and present an independent data-driven view of the land–atmosphere methanol exchange. Our study shows that the controls of plant growth on the production, and thus the methanol emission magnitude, and stomatal conductance on the hourly methanol emission variability, established at the leaf level, hold across sites at the ecosystem-level. Unequivocal evidence for bi-directional methanol exchange at the ecosystem scale is presented. Deposition, which at some sites even exceeds methanol emissions, represents an emerging feature of ecosystem-scale measurements and is likely related to environmental factors favouring the formation of surface wetness. Methanol may adsorb to or dissolve in this surface water and eventually be chemically or biologically removed from it. Management activities in agriculture and forestry are shown to increase local methanol emission by orders of magnitude; they are however neglected at present in global budgets. While contemporary net land methanol budgets are overall consistent with the grand mean of the micrometeorological methanol flux measurements, we caution that the present approach of simulating methanol emission and deposition separately is prone to opposing systematic errors and does not allow taking full

  15. Measuring conditions and trends in ecosystem services at multiple scales: the Southern African millennium ecosystem assessment (SAFMA) experience

    CSIR Research Space (South Africa)

    Van Jaarsveld, AS

    2005-01-01

    Full Text Available to ecosystems and for domestic use. Staple cereal production across the region has increased but was outstripped by population growth while protein malnutrition is on the rise. The much-anticipated wood-fuel crisis on the subcontinent has not materialized...

  16. Biofilm Growth and Turbulence Effects on Stream Ecosystem Respiration: Measurement by Resazurin

    Science.gov (United States)

    Haggerty, R.; Ribot, M.; Singer, G. A.; Martí, E.; Argerich, A.; Battin, T. J.; Agell, G.

    2011-12-01

    Stream ecosystem respiration was quantified via resazurin reduction in a series of 6 flume experiments, with the purpose of understanding how respiration is influenced by biofilms and presence of bedforms that resulted in increased turbulence intensity. Two streamside flumes (40 m x 0.4 m) with were constructed and operated in parallel. The first flume had no bedforms and the second had 10-cm bedforms built of impermeable material with a wavelength of 1.0 m. The bedforms were covered with a monolayer of gravel. Stream water was flushed through the flumes with a velocity of ~0.069 m/s. Ecosystem respiration was measured via resazurin transformation to resorufin. Three sets of experiments were conducted in each flume, one with minimal biofilms, one with 10 days of biofilm growth, and one with 30 days of biofilm growth. Velocity measurements were made throughout the flumes with acoustic Doppler velocimetry. Ecosystem respiration varied by a factor of 2.25 among the experiments. Respiration was nearly perfectly correlated (r2 = 0.99) to a combination of biofilm mass and turbulence intensity, with biofilm mass explaining 91% of the variation and turbulence intensity explaining the remainder of the variation.

  17. Time Resolved Measurement of Ecosystem-Atmosphere NH3 Exchange Using the Eddy Covariance Technique

    Science.gov (United States)

    Fischer, M. L.; Littlejohn, D.

    2005-12-01

    Quantifying ammonia fluxes between the land surface and atmosphere is required for effective control of air quality, improving agricultural practices, and understanding natural ecosystem function. Ammonia (NH3) is emitted in large but uncertain amounts from animal agriculture, in lesser amounts from imperfect use of nitrogen fertilizers in crop agriculture, from catalytic converters used on automobiles and other energy related industrial processes, and exchanged between the ecosystem and atmosphere by natural ecosystem processes on vast spatial scales. To address the need for accurate, time-resolved NH3 flux measurements, we have developed an eddy covariance (EC) instrument for direct measurements of NH3 flux. EC flux measurements of NH3 were not previously possible because instruments were not sufficiently sensitive at high frequencies required to capture rapid variations in surface layer NH3 concentrations. To overcome this hurdle we combined a tunable-diode-laser (TDL) spectrometer with a fast-response NH3 sampling inlet and automated pulse-response calibration system. Laboratory tests of the inlet system demonstrate that the response to 10 ppb step in NH3 concentration is well described by a double exponential model with (1/e) times of 0.3 (85% response) and 1.5 (15% response) seconds. This response combined with a routinely measured instrument stability of ~ 0.1 ppb (on 30 minute timescales) indicates that the instrumental contribution to noise in NH3 flux measurements is ~ 0.2 umol NH3 m-2 hr-1, sufficient to stringently test models for NH3 exchange under most conditions. Recent results of field work to verify the instrument performance and observe examples of NH3 exchange will be presented.

  18. Autochamber measurements of Net Ecosystem (CO2) Exchange at a subarctic mire in Northern Sweden

    Science.gov (United States)

    Walthall, M.; Parker-Smith, X.; Lawrence, R. D.; Crill, P. M.

    2015-12-01

    Northern latitude wetlands (>~50°N) are characterized by cold and wet conditions that result in low decomposition rates for plant litter. This process promotes the sequestration of carbon (C) in the form of organic matter (i.e. peat) and the formation of widespread peatands. Peatlands, particularly in the Northern Hemisphere, have accumulated C by removing atmospheric CO2 for approximately the past 10,000 years. Historically, peatlands represent a net C sink; however, increases in the global average temperature could alter peatlands ability to store carbon. With a warming climate and permafrost thaw, the pool of once stable soil organic C available for decomposition is increasing. Like all terrestrial ecosystems, a number of environmental factors (e.g. peat temperature and vegetation) play important roles in governing the fate of C in peatlands. Projected climate change is expected to affect these regulating factors. Subarctic peatlands in zones of discontinuous permafrost are experiencing widespread environmental changes due to climate warming. In this study, we present net ecosystem (CO2) exchange and δ13C-CO2 data from Stordalen Mire in northern Sweden (68°22'N, 19°03'E). Measurements were made using a quantum cascade laser spectrometer connected to automatic chambers placed in the three predominant ecosystems (a dry, elevated Palsa; an intermediate thaw regime dominated by Sphagnum spp. and; a completely thawed, inundated site dominated by Eriophorum angustifolium). Team was mentored by Mr. Ryan Lawrence from The University of New Hampshire.

  19. Regional inversion of CO2 ecosystem fluxes from atmospheric measurements. Reliability of the uncertainty estimates

    Energy Technology Data Exchange (ETDEWEB)

    Broquet, G.; Chevallier, F.; Breon, F.M.; Yver, C.; Ciais, P.; Ramonet, M.; Schmidt, M. [Laboratoire des Sciences du Climat et de l' Environnement, CEA-CNRS-UVSQ, UMR8212, IPSL, Gif-sur-Yvette (France); Alemanno, M. [Servizio Meteorologico dell' Aeronautica Militare Italiana, Centro Aeronautica Militare di Montagna, Monte Cimone/Sestola (Italy); Apadula, F. [Research on Energy Systems, RSE, Environment and Sustainable Development Department, Milano (Italy); Hammer, S. [Universitaet Heidelberg, Institut fuer Umweltphysik, Heidelberg (Germany); Haszpra, L. [Hungarian Meteorological Service, Budapest (Hungary); Meinhardt, F. [Federal Environmental Agency, Kirchzarten (Germany); Necki, J. [AGH University of Science and Technology, Krakow (Poland); Piacentino, S. [ENEA, Laboratory for Earth Observations and Analyses, Palermo (Italy); Thompson, R.L. [Max Planck Institute for Biogeochemistry, Jena (Germany); Vermeulen, A.T. [Energy research Centre of the Netherlands ECN, EEE-EA, Petten (Netherlands)

    2013-07-01

    The Bayesian framework of CO2 flux inversions permits estimates of the retrieved flux uncertainties. Here, the reliability of these theoretical estimates is studied through a comparison against the misfits between the inverted fluxes and independent measurements of the CO2 Net Ecosystem Exchange (NEE) made by the eddy covariance technique at local (few hectares) scale. Regional inversions at 0.5{sup 0} resolution are applied for the western European domain where {approx}50 eddy covariance sites are operated. These inversions are conducted for the period 2002-2007. They use a mesoscale atmospheric transport model, a prior estimate of the NEE from a terrestrial ecosystem model and rely on the variational assimilation of in situ continuous measurements of CO2 atmospheric mole fractions. Averaged over monthly periods and over the whole domain, the misfits are in good agreement with the theoretical uncertainties for prior and inverted NEE, and pass the chi-square test for the variance at the 30% and 5% significance levels respectively, despite the scale mismatch and the independence between the prior (respectively inverted) NEE and the flux measurements. The theoretical uncertainty reduction for the monthly NEE at the measurement sites is 53% while the inversion decreases the standard deviation of the misfits by 38 %. These results build confidence in the NEE estimates at the European/monthly scales and in their theoretical uncertainty from the regional inverse modelling system. However, the uncertainties at the monthly (respectively annual) scale remain larger than the amplitude of the inter-annual variability of monthly (respectively annual) fluxes, so that this study does not engender confidence in the inter-annual variations. The uncertainties at the monthly scale are significantly smaller than the seasonal variations. The seasonal cycle of the inverted fluxes is thus reliable. In particular, the CO2 sink period over the European continent likely ends later than

  20. Host preferences of arbuscular mycorrhizal fungi colonizing annual herbaceous plant species in semiarid Mediterranean prairies.

    Science.gov (United States)

    Torrecillas, E; Alguacil, M M; Roldán, A

    2012-09-01

    In this study, we have analyzed and compared the diversities of the arbuscular mycorrhizal fungi (AMF) colonizing the roots of five annual herbaceous species (Hieracium vulgare, Stipa capensis, Anagallis arvensis, Carduus tenuiflorus, and Avena barbata) and a perennial herbaceous species (Brachypodium retusum). Our goal was to determine the differences in the communities of the AMF among these six plant species belonging to different families, using B. retusum as a reference. The AMF small-subunit rRNA genes (SSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Thirty-six AMF phylotypes, belonging to Glomus group A, Glomus group B, Diversispora, Paraglomus, and Ambispora, were identified. Five sequence groups identified in this study clustered to known glomalean species or isolates: group Glomus G27 to Glomus intraradices, group Glomus G19 to Glomus iranicum, group Glomus G10 to Glomus mosseae, group Glomus G1 to Glomus lamellosum/etunicatum/luteum, and group Ambispora 1 to Ambispora fennica. The six plant species studied hosted different AMF communities. A certain trend of AMF specificity was observed when grouping plant species by taxonomic families, highlighting the importance of protecting and even promoting the native annual vegetation in order to maintain the biodiversity and productivity of these extreme ecosystems.

  1. Chamber and Diffusive Based Carbon Flux Measurements in an Alaskan Arctic Ecosystem

    Science.gov (United States)

    Wilkman, E.; Oechel, W. C.; Zona, D.

    2013-12-01

    Eric Wilkman, Walter Oechel, Donatella Zona Comprising an area of more than 7 x 106 km2 and containing over 11% of the world's organic matter pool, Arctic terrestrial ecosystems are vitally important components of the global carbon cycle, yet their structure and functioning are sensitive to subtle changes in climate and many of these functional changes can have large effects on the atmosphere and future climate regimes (Callaghan & Maxwell 1995, Chapin et al. 2002). Historically these northern ecosystems have acted as strong C sinks, sequestering large stores of atmospheric C due to photosynthetic dominance in the short summer season and low rates of decomposition throughout the rest of the year as a consequence of cold, nutrient poor, and generally water-logged conditions. Currently, much of this previously stored carbon is at risk of loss to the atmosphere due to accelerated soil organic matter decomposition in warmer future climates (Grogan & Chapin 2000). Although there have been numerous studies on Arctic carbon dynamics, much of the previous soil flux work has been done at limited time intervals, due to both the harshness of the environment and labor and time constraints. Therefore, in June of 2013 an Ultraportable Greenhouse Gas Analyzer (UGGA - Los Gatos Research Inc.) was deployed in concert with the LI-8100A Automated Soil Flux System (LI-COR Biosciences) in Barrow, AK to gather high temporal frequency soil CO2 and CH4 fluxes from a wet sedge tundra ecosystem. An additional UGGA in combination with diffusive probes, installed in the same location, provides year-round soil and snow CO2 and CH4 concentrations. When used in combination with the recently purchased AlphaGUARD portable radon monitor (Saphymo GmbH), continuous soil and snow diffusivities and fluxes of CO2 and CH4 can be calculated (Lehmann & Lehmann 2000). Of particular note, measuring soil gas concentration over a diffusive gradient in this way allows one to separate both net production and

  2. Mangrove recruitment after forest disturbance is facilitated by herbaceous species in the Caribbean

    Science.gov (United States)

    McKee, K.L.; Rooth, J.E.; Feller, Ilka C.

    2007-01-01

    Plant communities along tropical coastlines are often affected by natural and human disturbances, but little is known about factors influencing recovery. We focused on mangrove forests, which are among the most threatened ecosystems globally, to examine how facilitation by herbaceous vegetation might improve forest restoration after disturbance. We specifically investigated whether recovery of mangrove forests in harsh environments is accelerated by nurse plants and whether the beneficial effects are species-specific. Quantification of standardized effects allowed comparisons across performance parameters and over time for: (1) net effect of each herbaceous species on mangrove survival and growth, (2) effects of pre- and post-establishment factors associated with each herbaceous species, and (3) need for artificial planting to enhance growth or survival of mangrove seedlings. Mangrove recruitment in a clear-cut forest in Belize was accelerated by the presence of Sesuvium portulacastrum (succulent forb) and Distichlis spicata (grass), two coastal species common throughout the Caribbean region. The net effect of herbaceous vegetation was positive, but the magnitude of effects on mangrove survival and growth differed by species. Because of differences in their vegetative structure and other features, species effects on mangroves also varied by mechanism: (1) trapping of dispersing propagules (both species), (2) structural support of the seedling (Distichlis), and/or (3) promotion of survival (Sesuvium) or growth (Distichlis) through amelioration of soil conditions (temperature, aeration). Artificial planting had a stronger positive effect on mangrove survival than did edaphic conditions, but planting enhanced mangrove growth more in Sesuvium than in Distichlis patches. Our study indicates that beneficial species might be selected based on features that provide multiple positive effects and that species comparisons may be improved using standardized effects. Our

  3. Understanding soil erosion process within herbaceous vegetative hedges using plant functional traits approach in North-West Europe

    Science.gov (United States)

    Kervroëdan, Léa; Armand, Romain; Saunier, Mathieu; Faucon, Michel-Pierre

    2017-04-01

    Runoff and soil erosion induce major environmental and economic damages. Concentrated runoff control by aboveground plant biomass in upstream areas constitutes a key feature to reduce runoff and soil erosion in Western Europe (WE). Indeed, aboveground plant biomass can reduce runoff and soil erosion respectively by increasing hydraulic roughness and trapping sediments. However, studies of plant effect on runoff reduction are usually based on the taxonomical characterisation of species and do not refer to effect of aboveground plant functional traits. Plant functional traits approach allows to understand ecosystem processes and quantify services. Traits effect could vary depending on hydrological processes (i.e., discharge) and their aggregation could have a synergetic effect on hydraulic roughness and erosion reduction. In this study, objectives are to i) examine effects of aboveground plant functional traits of herbaceous hedges on hydraulic roughness; ii) test the effects of their aggregation on hydraulic roughness. Seven aboveground functional traits were measured on 14 indigenous plant species from North-West Europe with a high morphological variability (stem and leaf densities; stem diameter, stiffness and dry matter content; leaf area and specific leaf area (SLA)). Those species are perennial herbaceous caespitose or comprising dry biomass in winter. Effects of plant functional traits and their abundance within the community on hydraulic roughness were examined using a runoff simulator at four discharges. Furthermore, the effect of plant functional diversity was analysed using four monospecific (mono-trait) conditions compared to multispecific (multi-traits) conditions. Results showed traits and their abundance influence hydraulic roughness. Indeed, leaf density and leaf area (traits), as well as plant community weighted stem, leaf and shoot areas, stem diameter and SLA are significantly correlated to hydraulic roughness. Moreover, leaf density and leaf area

  4. Measuring ecosystem capacity to provide regulating services: forest removal and recovery at Hubbard Brook (USA).

    Science.gov (United States)

    Beier, Colin M; Caputo, Jesse; Groffman, Peter M

    2015-10-01

    In this study, by coupling long-term ecological data with empirical proxies of societal demand for benefits, we measured the capacity of forest watersheds to provide ecosystem services over variable time periods, to different beneficiaries, and in response to discrete perturbations and drivers of change. We revisited one of the earliest ecosystem experiments in North America: the 1963 de-vegetation of a forested catchment at Hubbard Brook Experimental Forest in New Hampshire, USA. Potential benefits of the regulation of water flow, water quality, greenhouse gases, and forest growth were compared between experimental (WS 2) and reference (WS 6) watersheds over a 30-year period. Both watersheds exhibited similarly high capacity for flow regulation, in part because functional loads remained low (i.e., few major storm events) during the de-vegetation period. Drought mitigation capacity, or the maintenance of flows sufficient to satisfy municipal water consumption, was higher in WS 2 due to reduced evapotranspiration associated with loss of plant cover. We also assessed watershed capacity to regulate flows to satisfy different beneficiaries, including hypothetical flood averse and drought averse types. Capacity to regulate water quality was severely degraded during de-vegetation, as nitrate concentrations exceeded drinking water standards on 40% of measurement days. Once forest regeneration began, WS 2 rapidly recovered the capacity to provide safe drinking water, and subsequently mitigated the eutrophication potential of rainwater at a marginally higher level than WS 6. We estimated this additional pollution removal benefit would have to accrue for approximately 65-70 years to offset the net eutrophication cost incurred during forest removal. Overall, our results affirmed the critical role of forest vegetation in water regulation, but also indicated trade-offs associated with forest removal and recovery that partially depend on larger-scale exogenous changes in climate

  5. UV radiation in global climate change. Measurements, modeling and effects on ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei; Slusser, James R. (eds.) [Colorado State Univ., CO (United States). Natural Resource Ecology Lab.; Schmoldt, Daniel L. [Waterfront Centre, Washington, DC (United States). Cooperative State Research Education and Extension Service

    2010-07-01

    Numerous studies report that ultraviolet (UV) radiation is harmful to living organisms and detrimental to human health. Growing concerns regarding the increased levels of UV-B radiation that reach the earth's surface have led to the development of ground- and space-based measurement programs. Further study is needed on the measurement, modeling, and effects of UV radiation. The chapters of this book describe the research conducted across the globe over the past three decades in the areas of: (1) current and predicted levels of UV radiation and its associated impact on ecosystems and human health, as well as economic and social implications; (2) new developments in UV instrumentation, advances in calibration (ground- and satellite-based), measurement methods, modeling efforts, and their applications; and (3) the effects of global climate change on UV radiation. (orig.)

  6. Data collection protocol : Great Sand Dunes National Park : Herbaceous production and offtake

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This protocol/SOP is from USGS for taking samples estimate the average percentage of herbaceous biomass consumed by ungulates and annual herbaceous productivity in...

  7. Perturbation-free measurement of in situ di-nitrogen emissions from denitrification in nitrate-rich aquatic ecosystems.

    Science.gov (United States)

    Qin, Shuping; Clough, Timothy; Luo, Jiafa; Wrage-Mönnig, Nicole; Oenema, Oene; Zhang, Yuming; Hu, Chunsheng

    2017-02-01

    Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) has greatly contributed to increased food production. However, enriching the biosphere with Nr has also caused a series of negative effects on global ecosystems, especially aquatic ecosystems. The main pathway converting Nr back into the atmospheric N2 pool is the last step in the denitrification process. Despite several attempts, there is still a need for perturbation-free methods for measuring in situ N2 fluxes from denitrification in aquatic ecosystems at the field scale. Such a method is needed to comprehensively quantify the N2 fluxes from aquatic ecosystems. Here we observed linear relationships between the δ(15)N-N2O signatures and the logarithmically transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the perturbation-free N2 flux from denitrification in nitrate-rich aquatic ecosystems can be inferred from these linear relationships. Our method allowed the determination of field-scale in situ N2 fluxes from nitrate-rich aquatic ecosystems both with and without overlaying water. The perturbation-free in situ N2 fluxes observed by the new method were almost one order of magnitude higher than those by the sediment core method. The ability of aquatic ecosystems to remove Nr may previously have been severely underestimated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Herbaceous weed control in loblolly pine plantations using flazasulfuron

    Science.gov (United States)

    Andrew W. Ezell; Jimmie L. Yeiser

    2015-01-01

    A total of 13 treatments were applied at four sites (two in Mississippi and two in Texas) to evaluate the efficacy of flazasulfuron applied alone or in mixtures for providing control of herbaceous weeds. All sites were newly established loblolly pine (Pinus taeda L.) plantations. Plots were evaluated monthly until 180 days after treatment. No phytotoxicity on pine...

  9. Wintering bird response to fall mowing of herbaceous buffers

    Science.gov (United States)

    Blank, P.J.; Parks, J.R.; Dively, G.P.

    2011-01-01

    Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous buffers. Buffers enrolled in Maryland's Conservation Reserve Enhancement Program (CREP) cannot be mowed during the primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing of buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), and White-throated Sparrows (Zonotrichia albicollis) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for wintering birds. ?? 2011 by the Wilson Ornithological Society.

  10. DEVELOPING HERBACEOUS ENERGY CROPS AS FEEDSTOCKS FOR BIOETHANOL PRODUCTION

    Science.gov (United States)

    Perennial herbaceous crops with high biomass yields are promising substrates for producing bioethnaol. A variety of biomasses including cool and warm season grasses and a legume are being evaluated for this purpose. As a first approach, biomass materials were pretreated with dilute-sulfuric acid a...

  11. Climate change scenarios of herbaceous production along an aridity gradient: vulnerability increases with aridity.

    Science.gov (United States)

    Golodets, Carly; Sternberg, Marcelo; Kigel, Jaime; Boeken, Bertrand; Henkin, Zalmen; Seligman, No'am G; Ungar, Eugene D

    2015-04-01

    Climate change is expected to reduce annual precipitation by 20% and increase its standard deviation by 20% in the eastern Mediterranean. We have examined how these changes may affect herbaceous aboveground net primary production (ANPP) and its inter-annual coefficient of variation (CV) in natural rangelands along a desert-Mediterranean precipitation gradient, at five sites representing arid, semi-arid, and Mediterranean-type ecosystems, respectively, all showing positive linear relationships between herbaceous ANPP and annual precipitation. Scenarios of reduced annual precipitation and increased inter-annual precipitation variability were defined by manipulating mean annual precipitation (MAP) and its standard deviation. We simulated precipitation and calculated ANPP using current ANPP-precipitation relationships. Our model predicts that reduced precipitation will strongly reduce ANPP in arid and semi-arid sites. Moreover, the effect of reduced precipitation on the CV of ANPP along the entire gradient may be modified by changes in inter-annual variability in MAP. Reduced precipitation combined with increased precipitation variability was the scenario most relevant to the wet end of the gradient, due to the increased likelihood for both dry and rainy years. In contrast, the scenario most relevant to the arid end of the gradient combined reduced precipitation with decreased precipitation variability, due to the strong effect on mean ANPP. All scenarios increased variability of ANPP along the entire gradient. However, the higher sensitivity of vegetation at arid and semi-arid sites (i.e., lower forage production) to future changes in the precipitation regime emphasizes the need to adapt grazing management in these ecosystems to secure their long-term viability as sustainable rangelands.

  12. Atmo-metabolomics: a new measurement approach for investigating aerosol composition and ecosystem functioning.

    Science.gov (United States)

    Rivas-Ubach, A.; Liu, Y.; Sardans, J.; Tfaily, M. M.; Kim, Y. M.; Bourrianne, E.; Paša-Tolić, L.; Penuelas, J.; Guenther, A. B.

    2016-12-01

    Aerosols play crucial roles in the processes controlling the composition of the atmosphere and the functioning of ecosystems. Gaining a deeper understanding of the chemical composition of aerosols is one of the major challenges for atmospheric and climate scientists and is beginning to be recognized as important for ecological research. Better comprehension of aerosol chemistry can potentially provide valuable information on atmospheric processes such as oxidation of organics and the production of cloud condensation nuclei as well as provide an approximation of the general status of an ecosystem through the measurement of certain stress biomarkers. In this study, we describe an efficient aerosol sampling method, the metabolite extraction and the analytical procedures for the chemical characterization of aerosols, namely, the atmo-metabolome. We used mass spectrometry (MS) coupled to liquid chromatography (LC-MS), gas chromatography (GC-MS) and Fourier transform ion cyclotron resonance (FT-ICR-MS) to characterize the atmo-metabolome of two marked seasons; spring and summer. Our sampling and extraction methods demonstrated to be suitable for aerosol chemical characterization with any of the analytical platforms used in this study. The atmo-metabolome between spring and summer showed overall statistically differences. We identified several metabolites that can be attributed to pollen and other plant-related aerosols. Spring aerosols exhibit higher concentrations of metabolites linked to higher plant activity while summer samples had higher concentrations of metabolites that may reflect certain oxidative stresses in primary producers. Moreover, the elemental composition of aerosols showed clear different between seasons. Summer aerosols were generally higher in molecular weight and with higher O/C ratios, indicating higher oxidation levels and condensation of compounds relative to spring. Our method represents an advanced approach for characterizing the composition of

  13. Mechanisms of herbaceous vegetation restoration successions

    Science.gov (United States)

    Pankratova, Lubov

    2017-04-01

    less suitable for later species. The fourth model of neutrality corresponds to the succession, considered as a population process, with the change of species populations of different life cycles and different ecological-phytocenotic types of strategies. Often this model applies only to the formation of the species composition but quantitative ratios between the species are caused by a weakened manifestation of favored, inhibiting or tolerance effects. All the mechanisms together provide the plant communities development from the beginning stages to the end due to system feedbacks (positive and negative). In the first stages of succession the ecosystem is able to resume quickly, indicating a fairly high resilience, which means the movement to a climax is constantly decreasing. The trend is opposite for self-sustainability or stability. In the early stages of succession, its value is low enough - the systems are very sensitive to external influences, responding to them with increased dynamism. The resident resistance is continuously growing with species increasing. As you get closer to menopause, the ecosystem becomes more sensitive to the effects of some catastrophic environmental factors, which means that with ongoing stable growth the factor of ecosystem rigidity going to a climax apparently even begins to decrease.

  14. Influence of tree cover on herbaceous layer development and carbon and water fluxes in a Portuguese cork-oak woodland

    Science.gov (United States)

    Dubbert, Maren; Mosena, Alexander; Piayda, Arndt; Cuntz, Matthias; Correia, Alexandra Cristina; Pereira, Joao Santos; Werner, Christiane

    2014-08-01

    Facilitation and competition between different vegetation layers may have a large impact on small-scale vegetation development. We propose that this should not only influence overall herbaceous layer yield but also species distribution and understory longevity, and hence the ecosystems carbon uptake capacity especially during spring. We analyzed the effects of trees on microclimate and soil properties (water and nitrate content) as well as the development of an herbaceous community layer regarding species composition, aboveground biomass and net water and carbon fluxes in a cork-oak woodland in Portugal, between April and November 2011. The presence of trees caused a significant reduction in photosynthetic active radiation of 35 mol m-2 d-1 and in soil temperature of 5 °C from April to October. At the same time differences in species composition between experimental plots located in open areas and directly below trees could be observed: species composition and abundance of functional groups became increasingly different between locations from mid April onwards. During late spring drought adapted native forbs had significantly higher cover and biomass in the open area while cover and biomass of grasses and nitrogen fixing forbs was highest under the trees. Further, evapotranspiration and net carbon exchange decreased significantly stronger under the tree crowns compared to the open during late spring and the die back of herbaceous plants occurred earlier and faster under trees. This was most likely caused by interspecific competition for water between trees and herbaceous plants, despite the more favorable microclimate conditions under the trees during the onset of summer drought.

  15. Measurement-based upscaling of Pan Arctic Net Ecosystem Exchange: the PANEEx project

    Science.gov (United States)

    Njuabe Mbufong, Herbert; Kusbach, Antonin; Lund, Magnus; Persson, Andreas; Christensen, Torben R.; Tamstorf, Mikkel P.; Connolly, John

    2016-04-01

    The high variability in Arctic tundra net ecosystem exchange (NEE) of carbon (C) can be attributed to the high spatial heterogeneity of Arctic tundra due to the complex topography. Current models of C exchange handle the Arctic as either a single or few ecosystems, responding to environmental change in the same manner. In this study, we developed and tested a simple pan Arctic NEE (PANEEx) model using the Misterlich light response curve (LRC) function with photosynthetic photon flux density (PPFD) as the main driving variable. Model calibration was carried out with eddy covariance carbon dioxide (CO2) data from 12 Arctic tundra sites. The model input parameters (Fcsat, Rd and α) were estimated as a function of air temperature (AirT) and leaf area index (LAI) and represent specific characteristics of the NEE-PPFD relationship, including the saturation flux, dark respiration and initial light use efficiency, respectively. LAI and air temperature were respectively estimated from empirical relationships with remotely sensed normalized difference vegetation index (NDVI) and land surface temperature (LST). These are available as MODIS Terra product MOD13Q1 and MOD11A1 respectively. Therefore, no specific knowledge of the vegetation type is required. The PANEEx model captures the spatial heterogeneity of the Arctic tundra and was effective in simulating 77% of the measured fluxes (r2 = 0.72, p agreement between the measured and modeled NEE may result from the disparity between ground-based measured LAI (used in model calibration) and remotely sensed LAI (estimated from NDVI and used in NEE estimation). Moreover, our results suggests that using simple linear regressions may be inadequate as parameters estimated using multiple linear regression showed better agreement between measured and modeled data. We propose recalibrating the model using multiple linear relationships between environmental variables and LRC parameters. This model could contribute significantly to

  16. Global and Regional Ecosystem Modeling: Databases of Model Drivers and Validation Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.J.

    2002-03-19

    Understanding global-scale ecosystem responses to changing environmental conditions is important both as a scientific question and as the basis for making policy decisions. The confidence in regional models depends on how well the field data used to develop the model represent the region of interest, how well the environmental model driving variables (e.g., vegetation type, climate, and soils associated with a site used to parameterize ecosystem models) represent the region of interest, and how well regional model predictions agree with observed data for the region. To assess the accuracy of global model forecasts of terrestrial carbon cycling, two Ecosystem Model-Data Intercomparison (EMDI) workshops were held (December 1999 and April 2001). The workshops included 17 biogeochemical, satellite-driven, detailed process, and dynamic vegetation global model types. The approach was to run regional or global versions of the models for sites with net primary productivity (NPP) measurements (i.e., not fine-tuned for specific site conditions) and analyze the model-data differences. Extensive worldwide NPP data were assembled with model driver data, including vegetation, climate, and soils data, to perform the intercomparison. This report describes the compilation of NPP estimates for 2,523 sites and 5,164 0.5{sup o}-grid cells under the Global Primary Production Data Initiative (GPPDI) and the results of the EMDI review and outlier analysis that produced a refined set of NPP estimates and model driver data. The EMDI process resulted in 81 Class A sites, 933 Class B sites, and 3,855 Class C cells derived from the original synthesis of NPP measurements and associated driver data. Class A sites represent well-documented study sites that have complete aboveground and below ground NPP measurements. Class B sites represent more numerous ''extensive'' sites with less documentation and site-specific information available. Class C cells represent estimates of

  17. [Measuring water ecological carrying capacity with the ecosystem-service-based ecological footprint (ESEF) method: Theory, models and application].

    Science.gov (United States)

    Jiao, Wen-jun; Min, Qing-wen; Li, Wen-hua; Fuller, Anthony M

    2015-04-01

    Integrated watershed management based on aquatic ecosystems has been increasingly acknowledged. Such a change in the philosophy of water environment management requires recognizing the carrying capacity of aquatic ecosystems for human society from a more general perspective. The concept of the water ecological carrying capacity is therefore put forward, which considers both water resources and water environment, connects socio-economic development to aquatic ecosystems and provides strong support for integrated watershed management. In this paper, the authors proposed an ESEF-based measure of water ecological carrying capacity and constructed ESEF-based models of water ecological footprint and capacity, aiming to evaluate water ecological carrying capacity with footprint methods. A regional model of Taihu Lake Basin was constructed and applied to evaluate the water ecological carrying capacity in Changzhou City which located in the upper reaches of the basin. Results showed that human demand for water ecosystem services in this city had exceeded the supply capacity of local aquatic ecosystems and the significant gap between demand and supply had jeopardized the sustainability of local aquatic ecosystems. Considering aqua-product provision, water supply and pollutant absorption in an integrated way, the scale of population and economy aquatic ecosystems in Changzhou could bear only 54% of the current status.

  18. Constraining Ecosystem Gross Primary Production and Transpiration with Measurements of Photosynthetic 13CO2 Discrimination

    Science.gov (United States)

    Blonquist, J. M.; Wingate, L.; Ogeé, J.; Bowling, D. R.

    2011-12-01

    The stable carbon isotope composition of atmospheric CO2 (δ13Ca) can provide useful information on water use efficiency (WUE) dynamics of terrestrial ecosystems and potentially constrain models of CO2 and water fluxes at the land surface. This is due to the leaf-level relationship between photosynthetic 13CO2 discrimination (Δ), which influences δ13Ca, and the ratio of leaf intercellular to atmospheric CO2 mole fractions (Ci / Ca), which is related to WUE and is determined by the balance between C assimilation (CO2 demand) and stomatal conductance (CO2 supply). We used branch-scale Δ derived from tunable diode laser absorption spectroscopy measurements collected in a Maritime pine forest to estimate Ci / Ca variations over an entire growing season. We combined Ci / Ca estimates with rates of gross primary production (GPP) derived from eddy covariance (EC) to estimate canopy-scale stomatal conductance (Gs) and transpiration (T). Estimates of T were highly correlated to T estimates derived from sapflow data (y = 1.22x + 0.08; r2 = 0.61; slope P MuSICA) (y = 0.88x - 0.05; r2 = 0.64; slope P MuSICA (y = 1.10 + 0.42; r2 = 0.50; slope P < 0.001). Results demonstrate that the leaf-level relationship between Δ and Ci / Ca can be extended to the canopy-scale and that Δ measurements have utility for partitioning ecosystem-scale CO2 and water fluxes.

  19. Nitrate removal in stream ecosystems measured by 15N addition experiments: Denitrification

    Science.gov (United States)

    Mulholland, P.J.; Hall, R.O.; Sobota, D.J.; Dodds, W.K.; Findlay, S.E.G.; Grimm, N. B.; Hamilton, S.K.; McDowell, W.H.; O'Brien, J. M.; Tank, J.L.; Ashkenas, L.R.; Cooper, L.W.; Dahm, Clifford N.; Gregory, S.V.; Johnson, S.L.; Meyer, J.L.; Peterson, B.J.; Poole, G.C.; Valett, H.M.; Webster, J.R.; Arango, C.P.; Beaulieu, J.J.; Bernot, M.J.; Burgin, A.J.; Crenshaw, C.L.; Helton, A.M.; Johnson, L.T.; Niederlehner, B.R.; Potter, J.D.; Sheibley, R.W.; Thomasn, S.M.

    2009-01-01

    We measured denitrification rates using a field 15N-NO- 3 tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification (SWden) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land-use categories, likely because of the wide range of conditions within each region and land use. N2 production rates far exceeded N2O production rates in all streams. The fraction of total NO-3 removal from water due to denitrification ranged from 0.5% to 100% among streams (median of 16%), and was related to NHz 4 concentration and ecosystem respiration rate (ER). Multivariate approaches showed that the most important factors controlling SWden were specific discharge (discharge / width) and NO-3 concentration (positive effects), and ER and transient storage zones (negative effects). The relationship between areal denitrification rate (Uden) and NO- 3 concentration indicated a partial saturation effect. A power function with an exponent of 0.5 described this relationship better than a Michaelis-Menten equation. Although Uden increased with increasing NO- 3 concentration, the efficiency of NO-3 removal from water via denitrification declined, resulting in a smaller proportion of streamwater NO-3 load removed over a given length of stream. Regional differences in stream denitrification rates were small relative to the proximate factors of NO-3 concentration and ecosystem respiration rate, and land use was an important but indirect control on denitrification in streams, primarily via its effect on NO-3 concentration. ?? 2009.

  20. Ecosystem, Nigeria

    African Journals Online (AJOL)

    Trend of Heavy Metal Concentrations in Lagos Lagoon. Ecosystem ... these various factors, Oyewo (1998) estimated levels of ... Measurement of some physico-chemical parameters ... Further analysis was carried out only where there was a ...

  1. The impact of changes in the amount and timing of precipitation on the herbaceous understorey of Mediterranean evergreen oak woodlands

    Science.gov (United States)

    Jongen, Marjan; Lecomte, Xavier; Pereira, João. S.

    2010-05-01

    In the Iberian Peninsula, the evergreen oak woodlands, called montados in Portugal and dehesas in Spain, are of great ecological and socio-economic importance. Dominated by evergreen Quercus species, these savanna-type woodlands are characterized by a widely separated tree stratum associated with an herbaceous understorey, dominated by C3 annual species. The productivity and biogeochemical cycles of the herbaceous layer are highly dependent on timing and magnitude of precipitation. Climate change scenarios for the region suggest not only increasing air temperatures, but also the possibility of decreasing spring precipitation, accompanied by an increase in the interval between precipitation events, which might cause drought conditions to occur. To understand the impact of hydrological changes on productivity and ecosystem processes of the herbaceous understorey in these ecosystems, water manipulation experiments are being carried out in Portugal. In autumn 2009, large (30 m2) rain-out shelters were constructed near Coruche (Portugal), with the aim of studying the effect of precipitation variability on the understorey vegetation in a managed cork oak woodland. Initially, the two treatments in the rain-out shelters will be: (1) ambient precipitation quantity, with a dry period of 7 days, and (2) ambient precipitation quantity with a dry period of 21 days. The 'ambient precipitation quantity' is based on historical precipitation data for the experimental site, with average annual precipitation of 680 mm. In addition to the above two treatments, there will be non-sheltered reference plots, receiving natural rainfall patterns. In the future we aim to reduce the precipitation quantity (-30%) with similar length of the dry periods as above. From February 2010 onwards, we will gather a full data set for environmental variables, as well as productivity, species composition, soil CO2 flux, soil nitrogen and photosynthesis. Preliminary results will be presented.

  2. CBTL Design Case Summary Conventional Feedstock Supply System - Herbaceous

    Energy Technology Data Exchange (ETDEWEB)

    Christopher T. Wright; Erin M. Searcy

    2012-02-01

    A conventional bale feedstock design has been established that represents supply system technologies, costs, and logistics that are achievable today for supplying herbaceous feedstocks as a blendstock with coal for energy production. Efforts are made to identify bottlenecks and optimize the efficiency and capacities of this supply system, within the constraints of existing local feedstock supplies, equipment, and permitting requirements. The feedstock supply system logistics operations encompass all of the activities necessary to move herbaceous biomass feedstock from the production location to the conversion reactor ready for blending and insertion. This supply system includes operations that are currently available such that costs and logistics are reasonable and reliable. The system modeled for this research project includes the uses of field-dried corn stover or switchgrass as a feedstock to annually supply an 800,000 DM ton conversion facility.

  3. An ecosystem approach to evaluate restoration measures in the lignite mining district of Lusatia/Germany

    Science.gov (United States)

    Schaaf, Wolfgang

    2015-04-01

    Lignite mining in Lusatia has a history of over 100 years. Open-cast mining directly affected an area of 1000 km2. Since 20 years we established an ecosystem oriented approach to evaluate the development and site characteristics of post-mining areas mainly restored for agricultural and silvicultural land use. Water and element budgets of afforested sites were studied under different geochemical settings in a chronosequence approach (Schaaf 2001), as well as the effect of soil amendments like sewage sludge or compost in restoration (Schaaf & Hüttl 2006). Since 10 years we also study the development of natural site regeneration in the constructed catchment Chicken Creek at the watershed scale (Schaaf et al. 2011, 2013). One of the striking characteristics of post-mining sites is a very large small-scale soil heterogeneity that has to be taken into account with respect to soil forming processes and element cycling. Results from these studies in combination with smaller-scale process studies enable to evaluate the long-term effect of restoration measures and adapted land use options. In addition, it is crucial to compare these results with data from undisturbed, i.e. non-mined sites. Schaaf, W., 2001: What can element budgets of false-time series tell us about ecosystem development on post-lignite mining sites? Ecological Engineering 17, 241-252. Schaaf, W. and Hüttl, R. F., 2006: Direct and indirect effects of soil pollution by lignite mining. Water, Air and Soil Pollution - Focus 6, 253-264. Schaaf, W., Bens, O., Fischer, A., Gerke, H.H., Gerwin, W., Grünewald, U., Holländer, H.M., Kögel-Knabner, I., Mutz, M., Schloter, M., Schulin, R., Veste, M., Winter, S. & Hüttl, R.F., 2011: Patterns and processes of initial terrestrial-ecosystem development. Journal of Plant Nutrition and Soil Science, 174, 229-239. Schaaf, W., Elmer, M., Fischer, A., Gerwin, W., Nenov, R., Pretsch, H. and Zaplate, M.K., 2013: Feedbacks between vegetation, surface structures and hydrology

  4. Measuring the impact of prescribed fire management on the carbon balance of a flatwoods ecosystem in Kissimmee, Florida

    Science.gov (United States)

    Becker, K.; Hinkle, C.

    2012-12-01

    It has been well documented that terrestrial ecosystems have a great potential to store and sequester carbon. Therefore, a former ranch land at the Disney Wilderness Preserve (DWP), Kissimmee, Florida, USA is being restored to native ecosystems and managed to preserve biodiversity and increase carbon storage. Here, we present measurements of C flux from an eddy covariance system located in a longleaf pine flatwoods ecosystem at DWP. C flux measurements were taken at the site before, during, and after a prescribed fire event. C stock measurements were also taken for aboveground biomass immediately before and after the fire, as well as one year post fire. This study indicated that this ecosystem typically serves as a net sink of C. However, the system became a net source of C immediately following the fire event, with a ~40% loss of aboveground C stock, but recovered to a net sink of C within 6 weeks of the fire. Annually this ecosystem was found to serve as a net C sink even with a prescribed fire event, with annual net ecosystem productivity (NEP) of 508 g C/m2 in a non-fire year (2010) and 237 g C/m2 in a fire year (2011). In addition to the fire, it is important to note that the growing season of 2011 was anomalously dry, which likely hindered productivity, and thus the NEP of the fire year would probably be more similar to the non-fire year under more typical hydrologic conditions. Despite the variability of rainfall between years, this study shows that the longleaf pine flatwoods ecosystem provides the service of C sequestration even in the context of frequent prescribed fire management.

  5. 内蒙古荒漠草原农牧交错带植被恢复措施对弃耕地草本群落的影响%Effect of Restoration Measures on Herbaceous Community Characteristics of Abandoned Land in Desert Steppe of Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    木兰; 张璞进; 刘亚红; 刘欣超; 任永峰; 王博; 高宇; 张君; 逯栓柱

    2016-01-01

    This study took abandoned land of desert steppe located in Siziwangqi and Wuchuan County as study objects to study how herbaceous community was influenced by different restoration measures and periods.The results showed that planting Caragana intermedia in the abandoned land of Siziwangqi and Medicago sativa in that of Wuchuan County could promote restoration succession of the zonal vegetation and increase the coverage and aboveground biomass of herbaceous community.With the increase of abandoned time,the number of total species,perennial herb species and annual and biennial herb species,and ShannonWiener index and Margalef index of plant community in the abandoned land of the two areas tended to decrease,while the zonal dominant species dominated the community gradually.Additionally,the coverage and biomass of plant community showed a trend of first decrease and then increase with the increase of the abandoned time.Therefore,the reasonable artificial disturbance in desert steppe would be beneficial for vegetation restoration of the abandoned land.The vegetation recovery of the abandoned land is a long process,so the abandoned land should be used cautiously.%以内蒙古阴山北麓四子王旗和武川县的荒漠草原农牧交错带弃耕地为研究对象,研究不同恢复措施和恢复年限对弃耕地草本植物群落的影响.研究结果显示,在相对干旱的四子王旗和相对湿润的武川县,荒漠草原弃耕地分别种植中间锦鸡儿和苜蓿有利于地带性植被恢复演替,可增加草本群落的盖度和地上生物量.随着弃耕年限的增加,四子王旗和武川县弃耕地总的物种数、多年生草本物种数和一、二年生草本物种数呈减少趋势,地带性优势物种在群落中逐渐占主导地位,植物群落的盖度和生物量出现了先降低后增加的趋势,植物群落的Shannon-Wiener指数和Margalef丰富度指数呈递减趋势.在荒漠草原合理的人工干扰有利于弃耕地的植被

  6. The Concept of Agricultural Productivity on Ecosystem Scale and Its Measurement

    Institute of Scientific and Technical Information of China (English)

    ZHU Wan-bin; QIU Hua-jiao; CHANG Xin; CHENG Xu

    2006-01-01

    What is the connotation and the extension of the productivity concept and how to calculate it are the core problems in evaluating an agricultural-production process. The attributes of agricultural production processes have changed greatly in the last 100 years, and the methods to describe and measure the productivity failed to keep in pace with the production processes, resulting in a totally vague, incomplete evaluation of the production processes. Sometimes the serious problem of pollution is ignored in the race to shortdated money making, thus leading to a blooming and flooding pollution;sometimes the great ecological benefits are ignored and the corresponding production processes suffer drastically from "economic deficit". With the old agricultural productivity indices, no prediction can be made of the ultimate effects of agroecosytem on mankind-pollution or welfare. A new concept, agricultural productivity on ecosystem scale (APES) and the related indices are defined here to solve these problems. Emergy and exergy are introduced to help the measurement of the indices. Emergy is the memory of energy, which can be used to measure the total cost, including natural capital and social capital. APES of the agroecosystem is the aggregated contributions of all components to mankind and its habitat in uniformed dimensions, it may be expressed in material, energy, information, organization, pollution and damage, etc., positive or negative, and are calculated based on exergy methods. And a related index agroecological coupling degree (ACD) shows sustainability.

  7. Herbaceous Peony (Paeonia lactiflora Pall. as an Alternative Source of Oleanolic and Ursolic Acids

    Directory of Open Access Journals (Sweden)

    Jun Tao

    2011-01-01

    Full Text Available Oleanolic acid (OA and ursolic acid (UA have been proven to possess many biological activities, and much attention is focused on the search for plants which are rich in OA and UA. In this report, the OA and UA accumulation characteristics were investigated in 47 cultivars of Chinese herbaceous peony (Paeonia lactiflora Pall. and were followed in three cultivars over different developmental stages as measured by high performance liquid chromatography (HPLC. OA and UA levels in leaves and stems demonstrated an overall upward trend from May 1 to September 15 except for UA in the leaves of “Hong Feng”. The maximum values of OA and UA in leaves of “Yangfei Chu Yu”, “Fen Zhu Pan” and “Hong Feng” were 852.98, 575.60, 290.48 μg/g FW and 924.94, 827.36, 432.67 μg/g FW, respectively. The maximum values of OA and UA in stems of “Yangfei Chu Yu”, “Fen Zhu Pan” and “Hong Feng” were 359.28, 90.49, 43.90 μg/g FW and 326.86, 82.25, 56.63 μg/g FW, respectively. OA and UA contents in leaves of 47 different herbaceous peony cultivars ranged from 66.73–618.12 and 36.23–665.14 μg/g FW, respectively, with average values of 171.62 and 227.57 μg/g FW, respectively. The results suggested that the aboveground parts of herbaceous peony may be used as an alternative source of OA and UA for medicinal purposes in addition to its ornamental purposes.

  8. Monitoring Phenology of Floodplain Grassland and Herbaceous Vegetation with Uav Imagery

    Science.gov (United States)

    van Iersel, W. K.; Straatsma, M. W.; Addink, E. A.; Middelkoop, H.

    2016-06-01

    River restoration projects, which aim at improved flood safety and increased ecological value, have resulted in more heterogeneous vegetation. However, they also resulted in increasing hydraulic roughness, which leads to higher flood water levels during peak discharges. Due to allowance of vegetation development and succession, both ecological and hydraulic characteristics of the floodplain change more rapidly over time. Monitoring of floodplain vegetation has become essential to document and evaluate the changing floodplain characteristics and associated functioning. Extraction of characteristics of low vegetation using single-epoch remote sensing data, however, remains challenging. The aim of this study was to (1) evaluate the performance of multi-temporal, high-spatial-resolution UAV imagery for extracting temporal vegetation height profiles of grassland and herbaceous vegetation in floodplains and (2) to assess the relation between height development and NDVI changes. Vegetation height was measured six times during one year in 28 field plots within a single floodplain. UAV true-colour and false-colour imagery of the floodplain were recorded coincidently with each field survey. We found that: (1) the vertical accuracy of UAV normalized digital surface models (nDSMs) is sufficiently high to obtain temporal height profiles of low vegetation over a growing season, (2) vegetation height can be estimated from the time series of nDSMs, with the highest accuracy found for combined imagery from February and November (RMSE = 29-42 cm), (3) temporal relations between NDVI and observed vegetation height show different hysteresis behaviour for grassland and herbaceous vegetation. These results show the high potential of using UAV imagery for increasing grassland and herbaceous vegetation classification accuracy.

  9. MONITORING PHENOLOGY OF FLOODPLAIN GRASSLAND AND HERBACEOUS VEGETATION WITH UAV IMAGERY

    Directory of Open Access Journals (Sweden)

    W. K. van Iersel

    2016-06-01

    Full Text Available River restoration projects, which aim at improved flood safety and increased ecological value, have resulted in more heterogeneous vegetation. However, they also resulted in increasing hydraulic roughness, which leads to higher flood water levels during peak discharges. Due to allowance of vegetation development and succession, both ecological and hydraulic characteristics of the floodplain change more rapidly over time. Monitoring of floodplain vegetation has become essential to document and evaluate the changing floodplain characteristics and associated functioning. Extraction of characteristics of low vegetation using single-epoch remote sensing data, however, remains challenging. The aim of this study was to (1 evaluate the performance of multi-temporal, high-spatial-resolution UAV imagery for extracting temporal vegetation height profiles of grassland and herbaceous vegetation in floodplains and (2 to assess the relation between height development and NDVI changes. Vegetation height was measured six times during one year in 28 field plots within a single floodplain. UAV true-colour and false-colour imagery of the floodplain were recorded coincidently with each field survey. We found that: (1 the vertical accuracy of UAV normalized digital surface models (nDSMs is sufficiently high to obtain temporal height profiles of low vegetation over a growing season, (2 vegetation height can be estimated from the time series of nDSMs, with the highest accuracy found for combined imagery from February and November (RMSE = 29-42 cm, (3 temporal relations between NDVI and observed vegetation height show different hysteresis behaviour for grassland and herbaceous vegetation. These results show the high potential of using UAV imagery for increasing grassland and herbaceous vegetation classification accuracy.

  10. Using Lidar and Radar measurements to constrain predictions of forest ecosystem structure and function.

    Science.gov (United States)

    Antonarakis, Alexander S; Saatchi, Sassan S; Chazdon, Robin L; Moorcroft, Paul R

    2011-06-01

    Insights into vegetation and aboveground biomass dynamics within terrestrial ecosystems have come almost exclusively from ground-based forest inventories that are limited in their spatial extent. Lidar and synthetic-aperture Radar are promising remote-sensing-based techniques for obtaining comprehensive measurements of forest structure at regional to global scales. In this study we investigate how Lidar-derived forest heights and Radar-derived aboveground biomass can be used to constrain the dynamics of the ED2 terrestrial biosphere model. Four-year simulations initialized with Lidar and Radar structure variables were compared against simulations initialized from forest-inventory data and output from a long-term potential-vegtation simulation. Both height and biomass initializations from Lidar and Radar measurements significantly improved the representation of forest structure within the model, eliminating the bias of too many large trees that arose in the potential-vegtation-initialized simulation. The Lidar and Radar initializations decreased the proportion of larger trees estimated by the potential vegetation by approximately 20-30%, matching the forest inventory. This resulted in improved predictions of ecosystem-scale carbon fluxes and structural dynamics compared to predictions from the potential-vegtation simulation. The Radar initialization produced biomass values that were 75% closer to the forest inventory, with Lidar initializations producing canopy height values closest to the forest inventory. Net primary production values for the Radar and Lidar initializations were around 6-8% closer to the forest inventory. Correcting the Lidar and Radar initializations for forest composition resulted in improved biomass and basal-area dynamics as well as leaf-area index. Correcting the Lidar and Radar initializations for forest composition and fine-scale structure by combining the remote-sensing measurements with ground-based inventory data further improved

  11. Successful water quality monitoring: The right combination of intent, measurement, interpretation, and a cooperating ecosystem

    Science.gov (United States)

    Soballe, D.M.

    1998-01-01

    Water quality monitoring is invaluable to ensure compliance with regulations, detect trends or patterns, and advance ecological understanding. However, monitoring typically measures only a few characteristics in a small fraction of a large and complex system, and thus the information contained in monitoring data depends upon which features of the ecosystem are actually captured by the measurements. Difficulties arise when these data contain something other than intended, but this can be minimized if the purpose of the sampling is clear, and the sampling design, measurements, and data interpretations are all compatible with this purpose. The monitoring program and data interpretation must also be properly matched to the structure and functioning of the system. Obtaining this match is sometimes an iterative process that demands a close link between research and monitoring. This paper focuses on water quality monitoring that is intended to track trends in aquatic resources and advance ecological understanding. It includes examples from three monitoring programs and a simulation exercise that illustrate problems that arise when the information content of monitoring data differs from expectation. The examples show (1) how inconsistencies among, or lack of information about, the basic elements of a monitoring program (intent, design, measurement, interpretation, and the monitored system) can produce a systematic difference (bias) between monitoring measurements and sampling intent or interpretation, and (2) that bias is not just a statistical consideration, but an insidious problem that can undermine the scientific integrity of a monitoring program. Some general suggestions are provided and hopefully these examples will help those engaged in water quality monitoring to enhance and protect the value of their monitoring investment.

  12. Net ecosystem exchange over heterogeneous Arctic tundra: Scaling between chamber and eddy covariance measurements

    Science.gov (United States)

    Fox, Andrew M.; Huntley, Brian; Lloyd, Colin R.; Williams, Mathew; Baxter, Robert

    2008-06-01

    Net ecosystem exchange (NEE) was estimated for an area of tundra near Abisko using both eddy covariance (EC) data and chamber measurements. This area of tundra is heterogeneous with six principal elements forming a landscape mosaic. Chamber measurements in patches of the individual mosaic elements were used to model NEE as a function of irradiance and temperature. The area around the EC mast was mapped, and a footprint model was used to simulate the varying source fraction attributable to each mosaic element. Various upscaling approaches were used to estimate NEE for comparison with NEE calculated from the EC observations. The results showed that EC measurements made for such a heterogeneous site are robust to the variations in NEE between mosaic elements that also vary substantially in their source fractions. However, they also revealed a large (˜60%) bias in the absolute magnitude of the cumulative negative NEE for a 40-day study period simulated by various upscaling approaches when compared to the value calculated from the EC observations. The magnitude of this bias, if applied to estimates for the entire tundra region, is substantial in relation to other components of the global carbon budget. Various hypotheses to account for this bias are discussed and, where possible, evaluated. A need is identified for more systematic sampling strategies when performing chamber measurements in order to assess the extent to which subjectivity of chamber location may account for much of the observed bias. If this is the origin of the bias, then upscaling approaches using chamber measurements may generally overestimate CO2 uptake.

  13. Measurement-based upscaling of pan Arctic net ecosystem exchange: the PANEEx project

    DEFF Research Database (Denmark)

    Mbufong, Herbert Njuabe; Kusbach, Antonin; Lund, Magnus

    2015-01-01

    The high variability in Arctic tundra net ecosystem exchange (NEE) of carbon (C) can be attributed to the high spatial heterogeneity of Arctic tundra due to the complex topography. Current models of C exchange handle the Arctic as either a single or few ecosystems, responding to environmental...

  14. Beyond monetary measurement : How to evaluate projects and policies using the ecosystem services framework

    NARCIS (Netherlands)

    Sijtsma, Frans J.; van der Heide, C. Martijn; van Hinsberg, Arjen

    2013-01-01

    In this paper we focus on how to achieve better decision support when decision-makers use the ecosystem services (ESS) framework to broaden their evaluations. We contribute to the debate on valuation of ecosystem services by inquiring into how the ESS framework relates to the judgement and measureme

  15. Beyond monetary measurement: How to evaluate projects and policies using the ecosystem services framework

    NARCIS (Netherlands)

    Sijtsma, F.J.; Heide, van der C.M.; Hinsberg, van A.

    2013-01-01

    In this paper we focus on how to achieve better decision support when decision-makers use the ecosystem services (ESS) framework to broaden their evaluations. We contribute to the debate on valuation of ecosystem services by inquiring into how the ESS framework relates to the judgement and measureme

  16. Measuring spatial patterns in floodplains: A step towards understanding the complexity of floodplain ecosystems: Chapter 6

    Science.gov (United States)

    Murray Scown,; Martin Thoms,; DeJager, Nathan R.; Gilvear, David J.; Greenwood, Malcolm T.; Thoms, Martin C.; Wood, Paul J.

    2016-01-01

    Floodplains can be viewed as complex adaptive systems (Levin, 1998) because they are comprised of many different biophysical components, such as morphological features, soil groups and vegetation communities as well as being sites of key biogeochemical processing (Stanford et al., 2005). Interactions and feedbacks among the biophysical components often result in additional phenomena occuring over a range of scales, often in the absence of any controlling factors (sensu Hallet, 1990). This emergence of new biophysical features and rates of processing can lead to alternative stable states which feed back into floodplain adaptive cycles (cf. Hughes, 1997; Stanford et al., 2005). Interactions between different biophysical components, feedbacks, self emergence and scale are all key properties of complex adaptive systems (Levin, 1998; Phillips, 2003; Murray et al., 2014) and therefore will influence the manner in which we study and view spatial patterns. Measuring the spatial patterns of floodplain biophysical components is a prerequisite to examining and understanding these ecosystems as complex adaptive systems. Elucidating relationships between pattern and process, which are intrinsically linked within floodplains (Ward et al., 2002), is dependent upon an understanding of spatial pattern. This knowledge can help river scientists determine the major drivers, controllers and responses of floodplain structure and function, as well as the consequences of altering those drivers and controllers (Hughes and Cass, 1997; Whited et al., 2007). Interactions and feedbacks between physical, chemical and biological components of floodplain ecosystems create and maintain a structurally diverse and dynamic template (Stanford et al., 2005). This template influences subsequent interactions between components that consequently affect system trajectories within floodplains (sensu Bak et al., 1988). Constructing and evaluating models used to predict floodplain ecosystem responses to

  17. Herbaceous Angiosperms Are Not More Vulnerable to Drought-Induced Embolism Than Angiosperm Trees1[OPEN

    Science.gov (United States)

    Delmas, Chloé E.L.; Buttler, Alexandre; Chauvin, Thibaud; Doria, Larissa Chacon; del Arco, Marcelino

    2016-01-01

    The water transport pipeline in herbs is assumed to be more vulnerable to drought than in trees due to the formation of frequent embolisms (gas bubbles), which could be removed by the occurrence of root pressure, especially in grasses. Here, we studied hydraulic failure in herbaceous angiosperms by measuring the pressure inducing 50% loss of hydraulic conductance (P50) in stems of 26 species, mainly European grasses (Poaceae). Our measurements show a large range in P50 from −0.5 to −7.5 MPa, which overlaps with 94% of the woody angiosperm species in a worldwide, published data set and which strongly correlates with an aridity index. Moreover, the P50 values obtained were substantially more negative than the midday water potentials for five grass species monitored throughout the entire growing season, suggesting that embolism formation and repair are not routine and mainly occur under water deficits. These results show that both herbs and trees share the ability to withstand very negative water potentials without considerable embolism formation in their xylem conduits during drought stress. In addition, structure-function trade-offs in grass stems reveal that more resistant species are more lignified, which was confirmed for herbaceous and closely related woody species of the daisy group (Asteraceae). Our findings could imply that herbs with more lignified stems will become more abundant in future grasslands under more frequent and severe droughts, potentially resulting in lower forage digestibility. PMID:27268961

  18. Measuring Animal Movements in a Natural Ecosystem: A Mark-Recapture Investigation Using Stream-Dwelling Snails

    Science.gov (United States)

    Stewart, Timothy W.

    2007-01-01

    In this investigation, students measure and describe movements of animals in a natural ecosystem. Students mark stream-dwelling snails with nail polish, then search for these snails 1-7 days later. Distances and directions moved by recaptured snails are recorded. Simple statistical techniques are used to answer specific research questions and…

  19. Uncertainty analysis of gross primary production partitioned from net ecosystem exchange measurements

    Directory of Open Access Journals (Sweden)

    R. Raj

    2015-08-01

    Full Text Available Gross primary production (GPP, separated from flux tower measurements of net ecosystem exchange (NEE of CO2, is used increasingly to validate process-based simulators and remote sensing-derived estimates of simulated GPP at various time steps. Proper validation should include the uncertainty associated with this separation at different time steps. This can be achieved by using a Bayesian framework. In this study, we estimated the uncertainty in GPP at half hourly time steps. We used a non-rectangular hyperbola (NRH model to separate GPP from flux tower measurements of NEE at the Speulderbos forest site, The Netherlands. The NRH model included the variables that influence GPP, in particular radiation, and temperature. In addition, the NRH model provided a robust empirical relationship between radiation and GPP by including the degree of curvature of the light response curve. Parameters of the NRH model were fitted to the measured NEE data for every 10-day period during the growing season (April to October in 2009. Adopting a Bayesian approach, we defined the prior distribution of each NRH parameter. Markov chain Monte Carlo (MCMC simulation was used to update the prior distribution of each NRH parameter. This allowed us to estimate the uncertainty in the separated GPP at half-hourly time steps. This yielded the posterior distribution of GPP at each half hour and allowed the quantification of uncertainty. The time series of posterior distributions thus obtained allowed us to estimate the uncertainty at daily time steps. We compared the informative with non-informative prior distributions of the NRH parameters. The results showed that both choices of prior produced similar posterior distributions GPP. This will provide relevant and important information for the validation of process-based simulators in the future. Furthermore, the obtained posterior distributions of NEE and the NRH parameters are of interest for a range of applications.

  20. Conservation Measures and Loss of Ecosystem Services: A Study Concerning the Sardinian Natura 2000 Network

    Directory of Open Access Journals (Sweden)

    Federica Leone

    2016-10-01

    Full Text Available The seeming dichotomy between the protection of biodiversity and the supply of ecosystem services (ESs represents an outstanding field of research that requires a structured and detailed analysis. The paper analyzes and discusses the role of ESs within spatial planning and strategic environmental assessment (SEA procedures through the content analysis methodology and a logical framework (LF implemented into the SEA of municipal masterplans (MMPs. We discuss the role of ESs as factors that improve the effectiveness of SEA-based processes related to management plans (MPs of sites that belong to the Sardinian Natura 2000 Network with reference to their positive impacts on environmental quality. The empirical outcomes put in evidence the inconsistencies between MMPs and MPs in terms of sustainability-oriented objectives and potential losses of the ESs productive output due to measures adopted by the MPs in order to protect habitats and species. The scant attention paid to ESs in the operational context of MMPs, MPs and SEA reports, particularly as regards their regulative framework, entails that the issue of the protection of ESs has to be carefully taken into account within the process of the definition and establishment of MPs through an SEA report that integrates the MPs and MMPs LFs.

  1. STUDY REGARDING TO AGGRESSIONS ON THE ECOSYSTEM DANUBE DELTA – BLACK SEA AND PROTECTIVE MEASURES

    Directory of Open Access Journals (Sweden)

    Ion Gr. IONESCU

    2014-06-01

    Full Text Available Danube Delta has suffered damages of habitat and species loss caused by factors, including: construction of dams upstream have degraded obviously flooding regime; creation of agricultural and fishing enclosures which decreased the natural and original surfaces; extending artificial navigation channels that negatively affected the hydrological regime and water quality of lakes; increase of nutrients in the water, industrial pollution and accumulate effluents that led to the reduction of plant and bird species; attempt to exploit quartz sand, very pure and fine, the sea levees, although they were protected as nature reserves because of the specific morphology and sub-Mediterranean vegetation covering them; tourism and illegal fishing; mismanagement of resources of reed and fish. The fact is that there was a slight improvement for the marine ecosystem, reported since the early 90s. At present, the area of the Danube Delta - Black Sea is developing sustainable, in terms of medium and economic perspective. In my study I used comparative methods, investigations, direct observations, measurements, calculations and actual data, obtained from surveys and direct observations, from prestigious, specialized and authorized institutions.

  2. STUDY REGARDING TO AGGRESSIONS ON THE ECOSYSTEM DANUBE DELTA – BLACK SEA AND PROTECTIVE MEASURES

    Directory of Open Access Journals (Sweden)

    Ion Gr. IONESCU

    2014-06-01

    Full Text Available Danube Delta has suffered damages of habitat and species loss caused by factors, including: construction of dams upstream have degraded obviously flooding regime; creation of agricultural and fishing enclosures which decreased the natural and original surfaces; extending artificial navigation channels that negatively affected the hydrological regime and water quality of lakes; increase of nutrients in the water, industrial pollution and accumulate effluents that led to the reduction of plant and bird species; attempt to exploit quartz sand, very pure and fine, the sea levees, although they were protected as nature reserves because of the specific morphology and sub-Mediterranean vegetation covering them; tourism and illegal fishing; mismanagement of resources of reed and fish. The fact is that there was a slight improvement for the marine ecosystem, reported since the early 90s. At present, the area of the Danube Delta - Black Sea is developing sustainable, in terms of medium and economic perspective. In my study I used comparative methods, investigations, direct observations, measurements, calculations and actual data, obtained from surveys and direct observations, from prestigious, specialized and authorized institutions.

  3. In situ biodeposition measurements on a Modiolus modiolus (horse mussel) reef provide insights into ecosystem services

    Science.gov (United States)

    Kent, Flora E. A.; Last, Kim S.; Harries, Daniel B.; Sanderson, William G.

    2017-01-01

    Horse mussel (Modiolus modiolus) shellfish reefs are a threatened and declining habitat in the North East Atlantic and support high levels of biodiversity. Shellfish can influence the surrounding water column and modify the quality of material that reaches the seabed by filtering water, actively depositing particles and changing the benthic boundary layer due to surface roughness. In the present study M. modiolus biodeposition was measured in a field location for the first time. The results show that M. modiolus enhance sedimentation and contribute to the downward flux of material to the seabed. Approximately 30% of the total sediment deposition was attributed to active filter feeding and overall, the presence of horse mussels enhanced deposition two fold. The results are discussed in terms of the potential for horse mussel reefs to provide ecosystem services to society, through functions such as benthopelagic coupling and sediment stabilisation. Highlighting the societal benefits supplied by marine habitats can help prioritise conservation efforts and feed into the sustainable management of coastal water bodies.

  4. Measuring aerobic respiration in stream ecosystems using the resazurin-resorufin system

    Science.gov (United States)

    GonzáLez-Pinzón, Ricardo; Haggerty, Roy; Myrold, David D.

    2012-09-01

    The use of smart tracers to study hydrologic systems is becoming more widespread. Smart tracers are compounds that irreversibly react in the presence of a process or condition under investigation. Resazurin (Raz) is a smart tracer that undergoes an irreversible reduction to resorufin (Rru) in the presence of cellular metabolic activity. We quantified the relationship between the transformation of Raz and aerobic bacterial respiration in pure culture experiments using two obligate aerobes and two facultative anaerobes, and in colonized surface and shallow (respiration in all experiments. These results suggest that Raz can be used as a surrogate to measure respiration in situ and in vivoat different spatial scales, thus providing an alternative to investigate mechanistic controls of solute transport and stream metabolism on nutrient processing. Lastly, a comparison of respiration and mass-transfer rates in streams suggests that field-scale respiration is controlled by the slower of respiration and mass transfer, highlighting the need to understand both biogeochemistry and physics in stream ecosystems.

  5. Science and Measurement Requirements for a Plant Physiology and Functional Types Mission: Measuring the Composition, Function and Health of Global Land and Coastal Ocean Ecosystems

    Science.gov (United States)

    Green, Robert O.; Rogez, Francois; Green, Rob; Ungar, Steve; Knox, Robert; Asner, Greg; Muller-Karger, Frank; Bissett, Paul; Chekalyuk, Alex; Dierssen, Heidi; Gamon, John; Hook, Simon; Meister, Gerhard; Middleton, Betsy; Ollinger, Scott; Roberts, Dar; Siegel, Dave; Townsend, Phil; Saatchi, Sassan; Unstin, Susan; Turner, Woody; Wickland, Diane; Bontempi, Paula; Emanuel, Bill

    2007-01-01

    This slide presentation reviews the proposed Plant Physiology and Functional Types (PPFT) Mission. The National Academy of Sciences Decadal Survey, placed a critical priority on a Mission to observe distribution and changes in ecosystem functions. The PPFT satellite mission provides the essential measurements needed to assess drivers of change in biodiversity and ecosystem services that affect human welfare. The presentation reviews the science questions that the mission will be designed to answer, the science rationale, the science measurements, the mission concept, the planned instrumentation, the calibration method, and key signal to noise ratios and uniformity requirements.

  6. Herbaceous species diversity patterns across various treatments of herbivory and fire along the sodic zone of the Nkuhlu exclosures, Kruger National Park

    Directory of Open Access Journals (Sweden)

    Helga van Coller

    2013-02-01

    Full Text Available Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones is critical to biodiversity conservation. The Nkuhlu exclosures in the Kruger National Park (KNP provided opportunity to investigate spatial heterogeneity patterns within riparian zones, as well as how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions about the dynamics of the herbaceous layer and was aimed at determining, (1 whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments in the ecologically sensitive sodic zone and (2 whether an increase in herbaceous biomass, an artefact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of 81 fixed plots. The biomass of each plot was estimated with a disc pasture meter (DPM diagonally with the plot. DPM-readings were converted to kg/ha, according to the latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass is significantly higher in fully fenced areas where herbivores are excluded, as opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. Therefore herbivores are essential in sustaining herbaceous plant species richness in the sodic zone, whilst no significant results were found with regard to their effect on species diversity. Although statistically non-significant, fire seems to

  7. Validation and improvement of MODIS Gross Primary Productivity in typical forest ecosystems of East Asia based on eddy covariance measurements

    Science.gov (United States)

    Zhou, Y.; He, M.; Ju, W.

    2011-12-01

    Terrestrial carbon cycle plays an important role in global climate change. As a key component of terrestrial carbon cycle, gross primary productivity (GPP) is a major determinant of carbon exchange between the atmosphere and terrestrial ecosystems. Because of the large spatial heterogeneity and temporal dynamics of ecosystems, it is a challenge to estimate GPP at global or regional scales. 8-day MODIS GPP product provides a real time estimate of global GPP. However, many previous studies indicated that MODIS GPP has large uncertainties, which was partly caused by biases in maximum light use efficiency and meteorological data inputs, including VPD, air temperature, and photosynthetically active radiation (PAR). In this study, MODIS GPP of six typical forest ecosystems in East Asia was validated using GPP derived from the eddy covariance flux measurements. The validation indicated that MODIS GPP was significantly underestimated in the forest ecosystems of East Asia. The underestimation is generally more serious in growing seasons than in non-growing seasons and becomes more obvious from the south to the north. By using observed meteorological data, smoothed fPAR and optimized maximum light use efficiency (ɛmax), predicted GPP with MOD17 algorithm consistently matched well with measured GPP. Smoothed fPAR definitely reduced underestimation of annual GPP, and the optimized ɛmax improved annual GPP more significantly, indicating that the errors in MODIS GPP of forest ecosystems in East Asia can be mainly attributed to the uncertainties of ɛmax. Optimized ɛmax are generally higher than that used for producing MODIS GPP product. The optimized ɛmax changes significantly with forest types. It even exhibits distinct seasonal variations for a specific forest. Key words: Gross Primary Productivity, MODIS, Maximum light use efficiency, East Asia, Forest ecosystem Correspondence author:Weimin Ju Email:juweimin@nju.edu.cn

  8. Building a better foundation: improving root-trait measurements to understand and model plant and ecosystem processes.

    Science.gov (United States)

    McCormack, M Luke; Guo, Dali; Iversen, Colleen M; Chen, Weile; Eissenstat, David M; Fernandez, Christopher W; Li, Le; Ma, Chengen; Ma, Zeqing; Poorter, Hendrik; Reich, Peter B; Zadworny, Marcin; Zanne, Amy

    2017-07-01

    Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well as plant impacts on ecosystem processes. Despite significant progress capturing trait variation within and among stems and leaves, identification of trait syndromes within fine-root systems and between fine roots and other plant organs is limited. Here we discuss three underappreciated areas where focused measurements of fine-root traits can make significant contributions to ecosystem science. These include assessment of spatiotemporal variation in fine-root traits, integration of mycorrhizal fungi into fine-root-trait frameworks, and the need for improved scaling of traits measured on individual roots to ecosystem-level processes. Progress in each of these areas is providing opportunities to revisit how below-ground processes are represented in terrestrial biosphere models. Targeted measurements of fine-root traits with clear linkages to ecosystem processes and plant responses to environmental change are strongly needed to reduce empirical and model uncertainties. Further identifying how and when suites of root and whole-plant traits are coordinated or decoupled will ultimately provide a powerful tool for modeling plant form and function at local and global scales. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  9. Effects of Torrefaction Temperature on Pyrolysis Vapor Products of Woody and Herbaceous Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Starace, Anne K.; Evans, Robert J.; Lee, David D.; Carpenter, Daniel L.

    2016-07-21

    A variety of hardwood, softwood, and herbaceous feedstocks (oak, southern yellow pine mix, loblolly pine, pinyon-juniper mix, and switchgrass) were each torrefied at 200, 250, and 300 degrees C. Each of the feedstocks was pyrolyzed and the resulting vapors were analyzed with a molecular beam mass spectrometer (py-MBMS). Compositional analysis was used to measure the total lignin content of three of the feedstocks (southern yellow pine, softwood; oak, hardwood; and switchgrass, herbaceous) before and after torrefaction at 300 degrees C, and large differences in the fraction of lignin lost during torrefaction were found between feedstocks, with oak having the largest decrease in lignin during torrefaction and switchgrass having the least. It is hypothesized that these differences in the thermal degradation are due to, in part, the different ratios of S, G, and H lignins in the feedstocks. Additionally, the torrefaction of kraft lignin was studied using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TGA-FTIR) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR).

  10. Measuring environmental change in forest ecosystems by repeated soil sampling: a North American perspective

    Science.gov (United States)

    Lawrence, Gregory B.; Fernandez, Ivan J.; Richter, Daniel D.; Ross, Donald S.; Hazlett, Paul W.; Bailey, Scott W.; Oiumet, Rock; Warby, Richard A.F.; Johnson, Arthur H.; Lin, Henry; Kaste, James M.; Lapenis, Andrew G.; Sullivan, Timothy J.

    2013-01-01

    Environmental change is monitored in North America through repeated measurements of weather, stream and river flow, air and water quality, and most recently, soil properties. Some skepticism remains, however, about whether repeated soil sampling can effectively distinguish between temporal and spatial variability, and efforts to document soil change in forest ecosystems through repeated measurements are largely nascent and uncoordinated. In eastern North America, repeated soil sampling has begun to provide valuable information on environmental problems such as air pollution. This review synthesizes the current state of the science to further the development and use of soil resampling as an integral method for recording and understanding environmental change in forested settings. The origins of soil resampling reach back to the 19th century in England and Russia. The concepts and methodologies involved in forest soil resampling are reviewed and evaluated through a discussion of how temporal and spatial variability can be addressed with a variety of sampling approaches. Key resampling studies demonstrate the type of results that can be obtained through differing approaches. Ongoing, large-scale issues such as recovery from acidification, long-term N deposition, C sequestration, effects of climate change, impacts from invasive species, and the increasing intensification of soil management all warrant the use of soil resampling as an essential tool for environmental monitoring and assessment. Furthermore, with better awareness of the value of soil resampling, studies can be designed with a long-term perspective so that information can be efficiently obtained well into the future to address problems that have not yet surfaced.

  11. Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

    Science.gov (United States)

    Hall, R.O.; Tank, J.L.; Sobota, D.J.; Mulholland, P.J.; O'Brien, J. M.; Dodds, W.K.; Webster, J.R.; Valett, H.M.; Poole, G.C.; Peterson, B.J.; Meyer, J.L.; McDowell, W.H.; Johnson, S.L.; Hamilton, S.K.; Grimm, N. B.; Gregory, S.V.; Dahm, Clifford N.; Cooper, L.W.; Ashkenas, L.R.; Thomas, S.M.; Sheibley, R.W.; Potter, J.D.; Niederlehner, B.R.; Johnson, L.T.; Helton, A.M.; Crenshaw, C.M.; Burgin, A.J.; Bernot, M.J.; Beaulieu, J.J.; Arangob, C.P.

    2009-01-01

    We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO-3 concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO-3 uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S Wtot). Uptake length increased with specific discharge (Q/w) and increasing NO-3 concentrations, showing a loss in removal efficiency in streams with high NO-3 concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO-3 removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO-3 uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO-3 uptake lengths via directly increasing both gross primary production and NO-3 concentration. Gross primary production shortened SWtot, while increasing NO-3 lengthened SWtot resulting in no net effect of land use on NO- 3 removal. ?? 2009.

  12. Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, Patrick J [ORNL; Hall, Robert [University of Wyoming, Laramie; Tank, Jennifer [University of Notre Dame, IN; Sobota, Daniel [Oregon State University; O' Brien, Jon [Michigan State University, East Lansing; Webster, Jackson [Virginia Polytechnic Institute and State University (Virginia Tech); Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Dodds, Walter [Kansas State University; Poole, Geoff [Eco-metrics; Peterson, Chris G. [Loyola University; Meyer, Judy [University of Georgia, Athens, GA; McDowell, William [University of Hew Hampshire; Johnson, Sherri [Oregon State University; Hamilton, Stephen [Michigan State University, East Lansing; Gregory, Stanley [Oregon State University, Corvallis; Grimm, Nancy [Arizona State University; Dahm, Cliff [University of New Mexico, Albuquerque; Cooper, Lee W [ORNL; Ashkenas, Linda [Oregon State University, Corvallis; Thomas, Suzanne [Marine Biological Laboratory; Sheibley, Rich [Arizona State University; Potter, Jody [University of New Hampshire; Niederlehner, Bobbie [Virginia Polytechnic Institute and State University (Virginia Tech); Johnson, Laura [University of Notre Dame, IN; Helton, Ashley [University of Georgia, Athens, GA; Crenshaw, Chelsea [University of New Mexico, Albuquerque; Burgin, Amy [Michigan State University, East Lansing; Bernot, Melody [Murray State University; Beaulieu, Jake [University of Notre Dame, IN; Arango, Clay [University of Notre Dame, IN

    2009-01-01

    We measured uptake length of {sup 15}NO{sub 3}{sup -} in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO{sub 3}{sup -} uptake length. As part of the Lotic Intersite Nitrogen Experiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO{sub 3}{sup -} concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO{sub 3}{sup -} uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S{sub Wtot}). Uptake length increased with specific discharge (Q/w) and increasing NO{sub 3}{sup -} concentrations, showing a loss in removal efficiency in streams with high NO{sub 3}{sup -} concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO{sub 3}{sup -} removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO{sub 3}{sup -} uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO{sub 3}{sup -} uptake lengths via directly increasing both gross primary production and NO{sub 3}{sup -} concentration. Gross primary production shortened S{sub Wtot}, while increasing NO{sub 3}{sup -} lengthened S{sub Wtot} resulting in no net effect of land use on NO{sub 3}{sup -} removal.

  13. Evapotranspiration measurement and crop coefficient estimation over a spring wheat Farmland ecosystem in the Loess Plateau.

    Science.gov (United States)

    Yang, Fulin; Zhang, Qiang; Wang, Runyuan; Zhou, Jing

    2014-01-01

    Evapotranspiration (ET) is an important component of the surface energy balance and hydrological cycle. In this study, the eddy covariance technique was used to measure ET of the semi-arid farmland ecosystem in the Loess Plateau during 2010 growing season (April to September). The characteristics and environmental regulations of ET and crop coefficient (Kc) were investigated. The results showed that the diurnal variation of latent heat flux (LE) was similar to single-peak shape for each month, with the largest peak value of LE occurring in August (151.4 W m(-2)). The daily ET rate of the semi-arid farmland in the Loess Plateau also showed clear seasonal variation, with the maximum daily ET rate of 4.69 mm day(-1). Cumulative ET during 2010 growing season was 252.4 mm, and lower than precipitation. Radiation was the main driver of farmland ET in the Loess Plateau, which explained 88% of the variances in daily ET (p<0.001). The farmland Kc values showed the obvious seasonal fluctuation, with the average of 0.46. The correlation analysis between daily Kc and its major environmental factors indicated that wind speed (Ws), relative humidity (RH), soil water content (SWC), and atmospheric vapor pressure deficit (VPD) were the major environmental regulations of daily Kc. The regression analysis results showed that Kc exponentially decreased with Ws increase, an exponentially increased with RH, SWC increase, and a linearly decreased with VPD increase. An experiential Kc model for the semi-arid farmland in the Loess Plateau, driven by Ws, RH, SWC and VPD, was developed, showing a good consistency between the simulated and the measured Kc values.

  14. Selection of herbaceous energy crops for the western corn belt

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, I.C.; Buxton, D.R.; Hallam, J.A. [Iowa State Univ. of Science and Technology, Ames, IA (United States)

    1994-05-01

    The ultimate economic feasibility of biomass depends on its cost of production and on the cost of competing fuels. The purpose of this research project is to evaluate the production costs of several combinations of species and management systems for producing herbaceous biomass for energy use in Iowa. Herbaceous biomass production systems have costs similar to other crop production systems, such as corn, soybean, and forages. Thus, the factors influencing the costs of producing dedicated biomass energy crops include technological factors such as the cultivation system, species, treatments, soil type, and site and economic factors such as input prices and use of fixed resources. In order to investigate how these production alternatives are influenced by soil resources, and climate conditions, two locations in Iowa, Ames and Chariton, with different soil types and slightly different weather patterns were selected for both the agronomic and economic analyses. Nine crops in thirteen cropping systems were grown at the two sites for five years, from 1988 to 1992. Some of the systems had multiple cropping or interplanting, using combinations of cool-season species and warm-season species, in order to meet multiple objectives of maximum biomass, minimal soil loss, reduced nitrogen fertilization or diminished pesticide inputs. Six of the systems use continuous monocropping of herbaceous crops with an emphasis on production. The seven other systems consist of similar crops, but with crop rotation and soil conservation considerations. While the erosion and other off-site effects of these systems is an important consideration in their overall evaluation, this report will concentrate on direct production costs only.

  15. The sclerophyllous Eucalyptus camaldulensis and herbaceous Nicotiana tabacum have different mechanisms to maintain high rates of photosynthesis

    Directory of Open Access Journals (Sweden)

    Wei Huang

    2016-11-01

    Full Text Available It is believed that high levels of mesophyll conductance (gm largely contribute to the high rates of photosynthesis in herbaceous C3 plants. However, some sclerophyllous C3 plants that display low levels of gm have high rates of photosynthesis, and the underlying mechanisms responsible for high photosynthetic rates in sclerophyllous C3 plants are unclear. In the present study, we examined photosynthetic characteristics in two high-photosynthesis plants (the sclerophyllous Eucalyptus camaldulensis and the herbaceous Nicotiana tabacum using measurements of gas exchange and chlorophyll fluorescence. Under saturating light intensities, both species had similar rates of CO2 assimilation at 400 μmol mol-1 CO2 (A400. However, E. camaldulensis exhibited significantly lower gm and chloroplast CO2 concentration (Cc than N. tabacum. A quantitative analysis revealed that, in E. camaldulensis, the gm limitation was the most constraining factor for photosynthesis. By comparison, in N. tabacum, the biochemical limitation was the strongest, followed by gm and gs limitations. In conjunction with a lower Cc, E. camaldulensis up-regulated the capacities of photorespiratory pathway and alternative electron flow. Furthermore, the rate of alternative electron flow was positively correlated with the rates of photorespiration and ATP supply from other flexible mechanisms, suggesting the important roles of photorespiratory pathway and alternative electron flow in sustaining high rate of photosynthesis in E. camaldulensis. These results highlight the different mechanisms used to maintain high rates of photosynthesis in the sclerophyllous E. camaldulensis and the herbaceous N. tabacum.

  16. The Sclerophyllous Eucalyptus camaldulensis and Herbaceous Nicotiana tabacum Have Different Mechanisms to Maintain High Rates of Photosynthesis

    Science.gov (United States)

    Huang, Wei; Tong, You-Gui; Yu, Guo-Yun; Yang, Wei-Xian

    2016-01-01

    It is believed that high levels of mesophyll conductance (gm) largely contribute to the high rates of photosynthesis in herbaceous C3 plants. However, some sclerophyllous C3 plants that display low levels of gm have high rates of photosynthesis, and the underlying mechanisms responsible for high photosynthetic rates in sclerophyllous C3 plants are unclear. In the present study, we examined photosynthetic characteristics in two high-photosynthesis plants (the sclerophyllous Eucalyptus camaldulensis and the herbaceous Nicotiana tabacum) using measurements of gas exchange and chlorophyll fluorescence. Under saturating light intensities, both species had similar rates of CO2 assimilation at 400 μmol mol−1 CO2 (A400). However, E. camaldulensis exhibited significantly lower gm and chloroplast CO2 concentration (Cc) than N. tabacum. A quantitative analysis revealed that, in E. camaldulensis, the gm limitation was the most constraining factor for photosynthesis. By comparison, in N. tabacum, the biochemical limitation was the strongest, followed by gm and gs limitations. In conjunction with a lower Cc, E. camaldulensis up-regulated the capacities of photorespiratory pathway and alternative electron flow. Furthermore, the rate of alternative electron flow was positively correlated with the rates of photorespiration and ATP supply from other flexible mechanisms, suggesting the important roles of photorespiratory pathway, and alternative electron flow in sustaining high rate of photosynthesis in E. camaldulensis. These results highlight the different mechanisms used to maintain high rates of photosynthesis in the sclerophyllous E. camaldulensis and the herbaceous N. tabacum. PMID:27933083

  17. Net ecosystem CO2 exchange and evapotranspiration of a sphagnum mire: field measurements and model simulations

    Science.gov (United States)

    Olchev, Alexander; Volkova, Elena; Karataeva, Tatiana; Zatsarinnaya, Dina; Novenko, Elena

    2014-05-01

    The spatial and temporal variability of net ecosystem exchange of CO2 (NEE) and evapotranspiration (ET) of a karst-hole sphagnum peat mire situated at the boundary between broad-leaved and forest-steppe zones in the central part of European Russia (54.06N, 37.59E, 260 m a.s.l.) was described using results of field measurements and simulations with Mixfor-3D model. The area of the mire is about 1.2 ha and it is surrounded by a broadleaved forest stand. It is a typical peat mire according to water and mineral supply as well as to vegetation composition. The vegetation of the peripheral parts of the mire is typical eutrophic whereas the vegetation in its central part is represented by meso-oligothrophic plant communities. To describe the spatial variability of NEE and ET within the mire a portable measuring system consisting of a transparent ventilated chamber combined with an infrared CO2 and H2O analyzer LI-840A (Li-Cor, USA) was used. The measurements were provided along a transect from the southern peripheral part of the mire to its center under sunny clear-sky weather conditions in the period from May to September of 2012 and from May 2013 to October 2013. The chamber method was used for measurements of NEE and ET fluxes because of small size of the mire, a very uniform surrounding forest stand and the mosaic mire vegetation. All these factors promote very heterogeneous exchange conditions within the mire and make it difficult to apply, for example, an eddy covariance method that is widely used for flux measurements in the field. The results of the field measurements showed a significant spatial and temporal variability of NEE and ET that was mainly influenced by incoming solar radiation, air temperature and ground water level. During the entire growing season the central part of the mire was a sink of CO2 for the atmosphere (up to 6.8±4.2 µmol m-2 s-1 in June) whereas its peripheral part, due to strong shading by the surrounding forest, was mainly a source of

  18. Ecosystem scale VOC exchange measurements at Bosco Fontana (IT) and Hyytiälä (FI)

    Science.gov (United States)

    Schallhart, S.; Rantala, P.; Taipale, R.; Nemitz, E.; Tillmann, R.; Mentel, T. F.; Ruuskanen, T.; Rinne, J.

    2013-12-01

    monoterpenes storages, which are emitted at high temperatures. The results of both forests are consistent with the cuvette measurements of Ghirardo et al. (2010). This research received funding from the EC Seventh Framework Programme (Collaborative project "ECLAIRE" grant no. 282910) and by the Academy of Finland Center of Excellence program (project number 141135). References.: Ghirardo, A., Koch, K., Taipale, R., Zimmer, I., Schnitzler, J-P. and Rinne, J. Determination of de novo and pool emissions of terpenes from four common boreal/alpine trees by 13CO2 labelling and PTR-MS analysis. Plant, Cell & Environment,33,5,781-792,2010. Taipale, R., Kajos, M.K., Patokoski, J., Rantala, P., Ruuskanen, T.M. and Rinne, J. Role of de novo biosynthesis in ecosystem scale monoterpene emissions from a boreal Scots pine forest. Biogeosciences, 8, 8, 2247-2255, 2011.

  19. How to measure ecosystem stability? An evaluation of the reliability of stability metrics based on remote sensing time series across the major global ecosystems.

    Science.gov (United States)

    De Keersmaecker, Wanda; Lhermitte, Stef; Honnay, Olivier; Farifteh, Jamshid; Somers, Ben; Coppin, Pol

    2014-07-01

    Increasing frequency of extreme climate events is likely to impose increased stress on ecosystems and to jeopardize the services that ecosystems provide. Therefore, it is of major importance to assess the effects of extreme climate events on the temporal stability (i.e., the resistance, the resilience, and the variance) of ecosystem properties. Most time series of ecosystem properties are, however, affected by varying data characteristics, uncertainties, and noise, which complicate the comparison of ecosystem stability metrics (ESMs) between locations. Therefore, there is a strong need for a more comprehensive understanding regarding the reliability of stability metrics and how they can be used to compare ecosystem stability globally. The objective of this study was to evaluate the performance of temporal ESMs based on time series of the Moderate Resolution Imaging Spectroradiometer derived Normalized Difference Vegetation Index of 15 global land-cover types. We provide a framework (i) to assess the reliability of ESMs in function of data characteristics, uncertainties and noise and (ii) to integrate reliability estimates in future global ecosystem stability studies against climate disturbances. The performance of our framework was tested through (i) a global ecosystem comparison and (ii) an comparison of ecosystem stability in response to the 2003 drought. The results show the influence of data quality on the accuracy of ecosystem stability. White noise, biased noise, and trends have a stronger effect on the accuracy of stability metrics than the length of the time series, temporal resolution, or amount of missing values. Moreover, we demonstrate the importance of integrating reliability estimates to interpret stability metrics within confidence limits. Based on these confidence limits, other studies dealing with specific ecosystem types or locations can be put into context, and a more reliable assessment of ecosystem stability against environmental disturbances

  20. Measuring and Mapping the Topography of the Florida Everglades for Ecosystem Restoration

    Science.gov (United States)

    Desmond, Gregory B.

    2003-01-01

    One of the major issues facing ecosystem restoration and management of the Greater Everglades is the availability and distribution of clean, fresh water. The South Florida ecosystem encompasses an area of approximately 28,000 square kilometers and supports a human population that exceeds 5 million and is continuing to grow. The natural systems of the Kissimmee-Okeechobee-Everglades watershed compete for water resources primarily with the region's human population and urbanization, and with the agricultural and tourism industries. Surface water flow modeling and ecological modeling studies are important means of providing scientific information needed for ecosystem restoration planning and modeling. Hydrologic and ecological models provide much-needed predictive capabilities for evaluating management options for parks, refuges, and land acquisition and for understanding the impacts of land management practices in surrounding areas. These models require various input data, including elevation data that very accurately define the topography of the Florida Everglades.

  1. Expected international demand for woody and herbaceous feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jacobson, Jacob [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mohammad, Roni [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wright, Christopher [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    The development of a U.S. bioenergy market and ultimately ‘bioeconomy’ has primarily been investigated with a national focus. Limited attention has been given to the potential impacts of international market developments. The goal of this project is to advance the current State of Technology of a single biorefinery to the global level providing quantitative estimates on how international markets may influence the domestic feedstock supply costs. The scope of the project is limited to feedstock that is currently available and new crops being developed to be used in a future U.S. bioeconomy including herbaceous residues (e.g., corn stover), woody biomass (e.g., pulpwood), and energy crops (e.g., switchgrass). The timeframe is set to the periods of 2022, 2030, and 2040 to align with current policy targets (e.g., the RFS2) and future updates of the Billion Ton data. This particular milestone delivers demand volumes for generic woody and herbaceous feedstocks for the main (net) importing regions along the above timeframes. The regional focus of the study is the European Union (EU), currently the largest demand region for U.S. pellets made from pulpwood and forest residues. The pellets are predominantly used in large-scale power plants (>5MWel) in the United Kingdom (UK), the Netherlands (NL), Belgium (BE), and Denmark (DK).

  2. Measuring conflicts in the management of anthropized ecosystems: Evidence from a choice experiment in a human-created Mediterranean wetland.

    Science.gov (United States)

    Perni, Ángel; Martínez-Paz, José Miguel

    2017-12-01

    Economic valuation of ecosystem services provides valuable information for the management of anthropized environments, where individual preferences can be heterogeneous and even opposed. Here, we discuss how these ecosystem services were approached in the literature and we address the main issues in relation to their economic valuation. We consider that avoiding misspecifications in economic valuation surveys requires considering the linkages between anthropized ecosystems and human intervention. To illustrate, we analyse the case study of a human-created Mediterranean wetland (El Hondo, SE Spain) using a Choice Experiment. Our findings suggest that management strategies in El Hondo should be oriented to improve the water ecological status, to enhance biodiversity and to develop ecotourism, whereas hunting should be strictly limited and controlled. Our measures of conflict (trade-off between ecosystem services and willingness to pay values) can help to find the optimal allocation of public and private goods and services and for the implementation of compensation schemes in the area. According to public preferences, a conservationist management strategy would generate 331,100 €/year in terms of environmental benefits, whereas a tourism-based management strategy would benefit society with 805,200 €/year. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Spring flowering herbaceous plant species of the deciduous forests of eastern Canada and 20th century climate warming

    Energy Technology Data Exchange (ETDEWEB)

    Houle, G. [Laval Univ., Quebec City, PQ (Canada). Dept. of Biology

    2007-02-15

    The rise in greenhouse gas emissions during the second half of the twentieth century has been associated with global climate warming. High latitude areas are particularly sensitive to such changes, with significant impacts on plant pheno logy. This article presented the results of a study that estimated changes in the flowering dates of 18 spring-flowering herbaceous plant species typical of the deciduous forests of eastern North America in three areas of eastern Canada, namely the Ottawa region, Montreal, and Quebec. Analyses were carried out for those species comprising more than 30 specimens covering a period of more than 50 years between 1900 to 2000. The purpose was to determine if spring-flowering herbaceous perennials showed signs for earlier flowering due to a rise in temperature. Only a few species from the 3 regions showed a significant flowering date/year regression, indicating that most species tended to flower earlier towards the end of the twentieth century. The data on indigenous plant species of natural habitats revealed noticeable shifts in phenology, particularly in the Montreal region. It was determined that the effects of climate warming on plant phenology may be exacerbated by local conditions associated with large urban areas. It was concluded that the species-specific response to climate change presented in this study may lead to important changes in ecosystem functions and community composition. 45 refs., 1 tab., 2 figs.

  4. An Improved Estimation of Regional Fractional Woody/Herbaceous Cover Using Combined Satellite Data and High-Quality Training Samples

    Directory of Open Access Journals (Sweden)

    Xu Liu

    2017-01-01

    Full Text Available Mapping vegetation cover is critical for understanding and monitoring ecosystem functions in semi-arid biomes. As existing estimates tend to underestimate the woody cover in areas with dry deciduous shrubland and woodland, we present an approach to improve the regional estimation of woody and herbaceous fractional cover in the East Asia steppe. This developed approach uses Random Forest models by combining multiple remote sensing data—training samples derived from high-resolution image in a tailored spatial sampling and model inputs composed of specific metrics from MODIS sensor and ancillary variables including topographic, bioclimatic, and land surface information. We emphasize that effective spatial sampling, high-quality classification, and adequate geospatial information are important prerequisites of establishing appropriate model inputs and achieving high-quality training samples. This study suggests that the optimal models improve estimation accuracy (NMSE 0.47 for woody and 0.64 for herbaceous plants and show a consistent agreement with field observations. Compared with existing woody estimate product, the proposed woody cover estimation can delineate regions with subshrubs and shrubs, showing an improved capability of capturing spatialized detail of vegetation signals. This approach can be applicable over sizable semi-arid areas such as temperate steppes, savannas, and prairies.

  5. Measuring soil frost depth in forest ecosystems with ground penetrating radar

    Science.gov (United States)

    John R. Butnor; John L. Campbell; James B. Shanley; Stanley. Zarnoch

    2014-01-01

    Soil frost depth in forest ecosystems can be variable and depends largely on early winter air temperatures and the amount and timing of snowfall. A thorough evaluation of ecological responses to seasonally frozen ground is hampered by our inability to adequately characterize the frequency, depth, duration and intensity of soil frost events. We evaluated the use of...

  6. A comparison of time series similarity measures for classification and change detection of ecosystem dynamics

    NARCIS (Netherlands)

    Lhermitte, S.; Verbesselt, J.; Verstraeten, W.W.; Coppin, P.

    2011-01-01

    Time series of remote sensing imagery or derived vegetation indices and biophysical products have been shown particularly useful to characterize land ecosystem dynamics. Various methods have been developed based on temporal trajectory analysis to characterize, classify and detect changes in ecosyste

  7. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009

    Science.gov (United States)

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  8. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon

    Science.gov (United States)

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  9. A study on herbaceous layer in an age series of restored mined land using cluster analysis

    Directory of Open Access Journals (Sweden)

    Shikha Uniyal Gairola

    2013-06-01

    Full Text Available Vegetation may be described as the plant life of a region. The study of patterns and processes in vegetation at various scales of space and time is useful in understanding landscapes, ecological processes, environmental history and predicting ecosystem attributes such as productivity. Generalized vegetation descriptions, maps and other graphical representations of vegetation types have become fundamental to land use planning and management. They are widely used as biodiversity surrogates in conservation assessments and can provide a useful summary of many non-vegetation landscape elements such as animal habitats, agricultural suitability and the location and abundance of timber and other forest resources. Clustering vegetation data is well known machine learning problem which aims to partition the data set into subsets, so that the data in each subset share some common trait. Present study was done with an objective to study the successional changes in herbaceous vegetation in an age series of restored mined land and also analyzes them by subjecting the vegetation data to cluster analysis. The results of the study reveals that with widespread distribution and dominance of some of the prominent naturals invaders as component of both - the mined sites as well as the undisturbed natural site, the final composition of the community at the restored sites are compiled solely from the existing population of the species and the succession on restored area results in the similar community as that found on undisturbed forest in the same vicinity.

  10. Forest fragmentation effects on patch occupancy and population viability of herbaceous plant species.

    Science.gov (United States)

    Honnay, Olivier; Jacquemyn, Hans; Bossuyt, Beatrijs; Hermy, Martin

    2005-06-01

    Habitat fragmentation is one of the major threats to species diversity. In this review, we discuss how the genetic and demographic structure of fragmented populations of herbaceous forest plant species is affected by increased genetic drift and inbreeding, reduced mate availability, altered interactions with pollinators, and changed environmental conditions through edge effects. Reported changes in population genetic and demographic structure of fragmented plant populations have, however, not resulted in large-scale extinction of forest plants. The main reason for this is very likely the long-term persistence of small and isolated forest plant populations due to prolonged clonal growth and long generation times. Consequently, the persistence of small forest plant populations in a changing landscape may have resulted in an extinction debt, that is, in a distribution of forest plant species reflecting the historical landscape configuration rather than the present one. In some cases, fragmentation appears to affect ecosystem integrity rather than short-term population viability due to the opposition of different fragmentation-induced ecological effects. We finally discuss extinction and colonization dynamics of forest plant species at the regional scale and suggest that the use of the metapopulation concept, both because of its heuristic power and conservation applications, may be fruitful.

  11. Forest Ecosystem respiration estimated from eddy covariance and chamber measurements under high turbulence and substantial tree mortality from bark beetles

    Science.gov (United States)

    Speckman, Heather N.; Frank, John M.; Bradford, John B.; Miles, Brianna L.; Massman, William J.; Parton, William J.; Ryan, Michael G.

    2015-01-01

    Eddy covariance nighttime fluxes are uncertain due to potential measurement biases. Many studies report eddy covariance nighttime flux lower than flux from extrapolated chamber measurements, despite corrections for low turbulence. We compared eddy covariance and chamber estimates of ecosystem respiration at the GLEES Ameriflux site over seven growing seasons under high turbulence (summer night mean friction velocity (u*) = 0.7 m s−1), during which bark beetles killed or infested 85% of the aboveground respiring biomass. Chamber-based estimates of ecosystem respiration during the growth season, developed from foliage, wood and soil CO2 efflux measurements, declined 35% after 85% of the forest basal area had been killed or impaired by bark beetles (from 7.1 ±0.22 μmol m−2 s−1 in 2005 to 4.6 ±0.16 μmol m−2 s−1 in 2011). Soil efflux remained at ~3.3 μmol m−2 s−1 throughout the mortality, while the loss of live wood and foliage and their respiration drove the decline of the chamber estimate. Eddy covariance estimates of fluxes at night remained constant over the same period, ~3.0 μmol m−2 s−1 for both 2005 (intact forest) and 2011 (85% basal area killed or impaired). Eddy covariance fluxes were lower than chamber estimates of ecosystem respiration (60% lower in 2005, and 32% in 2011), but the mean night estimates from the two techniques were correlated within a year (r2 from 0.18-0.60). The difference between the two techniques was not the result of inadequate turbulence, because the results were robust to a u* filter of > 0.7 m s−1. The decline in the average seasonal difference between the two techniques was strongly correlated with overstory leaf area (r2=0.92). The discrepancy between methods of respiration estimation should be resolved to have confidence in ecosystem carbon flux estimates.

  12. Effect of livestock grazing and human uses on herbaceous species diver-sity in oriental beech (Fagus orientalis Lipsky) forests, Guilan, Masal, northern Iran

    Institute of Scientific and Technical Information of China (English)

    Sepide Sadat Ebrahimi; Hassan Pourbabaei; David Potheir; Ali Omidi; Javad Torkaman

    2014-01-01

    Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human uses on herbaceous species diversity. We surveyed 50 ha of pro-tected area and 50 ha of unprotected area to evaluate herbaceous species diversity in oriental beech (Fagus orientalis Lipsky) forests in northern Iran. We calculated and compared three indices each of diversity and evenness, and species richness between the two areas. Herbaceous cover was higher in the unprotected area while leaf litter depth and tree canopy cover were higher in the protected area. The diversity indices, H (Shan-non-Wiener index ), N1 (McArthur index), N2 (Hill΄s index), EQ (Modified Nee index), Evar (Smith-Wilson index), E5 (modified index of Hill) and R=S (species richness) and species richness R=S were greater in the protected area than in the unprotected area, suggesting that protection from grazing results in increased numbers of plants and species. The effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and even-ness indices was higher than that between diversity and richness.

  13. Assessing nitrogen dynamics in European ecosystems, integrating measurement and modelling: conclusions

    Directory of Open Access Journals (Sweden)

    A. J. Wade

    2004-01-01

    Full Text Available This contribution closes this special issue of Hydrology and Earth System Sciences concerning the assessment of nitrogen dynamics in catchments across Europe within a semi-distributed Integrated Nitrogen model for multiple source assessment in Catchments (INCA. New developments in the understanding of the factors and processes determining the concentrations and loads of nitrogen are outlined. The ability of the INCA model to simulate the hydrological and nitrogen dynamics of different European ecosystems is assessed and the results of the first scenario analyses investigating the impacts of deposition, climatic and land-use change on the nitrogen dynamics are summarised. Consideration is given as to how well the model has performed as a generic tool for describing the nitrogen dynamics of European ecosystems across Arctic, Maritime, Continental and Mediterranean climates, its role in new research initiatives and future research requirements. Keywords: nitrogen, nitrate, ammonium, phosphorus, catchments, streams, rivers, river basins

  14. Rural herbaceous plant diversity under different land uses in North Zhejiang Province%浙北地区不同土地利用下乡村草本层植物多样性研究

    Institute of Scientific and Technical Information of China (English)

    吴灏; 张建锋; 陈光才; 汪庆兵; 王丽; 张颖

    2016-01-01

    该文以浙江省安吉县两个典型乡村—繅舍村和赋石村为例,选取公园、农耕区、河道、人工林地四种不同土地利用类型,用Shannon-Wiener指数、Simpson指数、Sorensen指数为标识多样性的指标,分析不同生境下草本植物多样性差异。结果表明:乡村生境中共记录物种162种,分属47科123属,其中禾本科与菊科物种数占总数的31.48%;农耕区生境的Shannon-Wiener指数、Simpson指数最高,分别为2.76和0.91,农耕区与河道的Sorensen指数最高为0.57。从农耕区、河道、公园到林地生境,草本物种多样性整体呈减小趋势。另外,发现人工绿化措施会导致草本物种减少,如从种植水稻单一作物到复合作物,草本层植物随之改变。单一稻田与复合种植区比较,草本植物主要的科属组成无明显变化,莎草科、菊科、禾本科植物仍占主体;但草本植物群落主要物种组成发生变化,稻田转变成农耕区后,牛筋草、黑麦草,碎米荠、小飞蓬、喜旱莲子草成为草本层群落主要构成植物,水竹叶覆盖度减少,小飞蓬和喜旱莲子草的覆盖度增加。此外,还发现4种生境中共有喜旱莲子草、加拿大一枝黄花、土荆芥三种入侵物种,但未能对本土物种构成显著影响。这表明不同土地利用方式会严重影响草本群落物种组成及物种多样性;土地利用方式的变化,会引起草本植物主要群落构成发生改变;土地利用类型的多样化有利于本土草本物种多样性生存。该研究结果有助于为城镇化进程中保护乡村植物多样性、加速推进美丽中国建设提供技术支撑。%Local plants were important for ecosystem diversity, of which herbaceous plants took a great account. In the article Fushi Village and Saoshe Village in Zhejiang Province were taken as test plots, where land use systems were di-vided into four artificial habits such as artificial forest, gardens, rivers

  15. Cost Methodology for Biomass Feedstocks: Herbaceous Crops and Agricultural Residues

    Energy Technology Data Exchange (ETDEWEB)

    Turhollow Jr, Anthony F [ORNL; Webb, Erin [ORNL; Sokhansanj, Shahabaddine [ORNL

    2009-12-01

    This report describes a set of procedures and assumptions used to estimate production and logistics costs of bioenergy feedstocks from herbaceous crops and agricultural residues. The engineering-economic analysis discussed here is based on methodologies developed by the American Society of Agricultural and Biological Engineers (ASABE) and the American Agricultural Economics Association (AAEA). An engineering-economic analysis approach was chosen due to lack of historical cost data for bioenergy feedstocks. Instead, costs are calculated using assumptions for equipment performance, input prices, and yield data derived from equipment manufacturers, research literature, and/or standards. Cost estimates account for fixed and variable costs. Several examples of this costing methodology used to estimate feedstock logistics costs are included at the end of this report.

  16. Assessing ecosystem response to multiple disturbances and climate change in South Africa using ground- and satellite-based measurements and model

    Science.gov (United States)

    Kutsch, W. L.; Falge, E. M.; Brümmer, C.; Mukwashi, K.; Schmullius, C.; Hüttich, C.; Odipo, V.; Scholes, R. J.; Mudau, A.; Midgley, G.; Stevens, N.; Hickler, T.; Scheiter, S.; Martens, C.; Twine, W.; Iiyambo, T.; Bradshaw, K.; Lück, W.; Lenfers, U.; Thiel-Clemen, T.; du Toit, J.

    2015-12-01

    Sub-Saharan Africa currently experiences rapidly growing human population, intrinsically tied to substantial changes in land use on shrubland, savanna and mixed woodland ecosystems due to over-exploitation. Significant conversions driving degradation, affecting fire frequency and water availability, and fueling climate change are expected to increase in the immediate future. However, measured data of greenhouse gas emissions as affected by land use change are scarce to entirely lacking from this region. The project 'Adaptive Resilience of Southern African Ecosystems' (ARS AfricaE) conducts research and develops scenarios of ecosystem development under climate change, for management support in conservation or for planning rural area development. This will be achieved by (1) creation of a network of research clusters (paired sites with natural and altered vegetation) along an aridity gradient in South Africa for ground-based micrometeorological in-situ measurements of energy and matter fluxes, (2) linking biogeochemical functions with ecosystem structure, and eco-physiological properties, (3) description of ecosystem disturbance (and recovery) in terms of ecosystem function such as carbon balance components and water use efficiency, (4) set-up of individual-based models to predict ecosystem dynamics under (post) disturbance managements, (5) combination with long-term landscape dynamic information derived from remote sensing and aerial photography, and (6) development of sustainable management strategies for disturbed ecosystems and land use change. Emphasis is given on validation (by a suite of field measurements) of estimates obtained from eddy covariance, model approaches and satellite derivations.

  17. Dune-scale distribution pattern of herbaceous plants and their relationship with environmental factors in a saline-alkali desert in Central Asia.

    Science.gov (United States)

    Tao, Ye; Wu, Gan-Lin; Zhang, Yuan-Ming

    2017-01-15

    Sand dunes are the main landforms in modern deserts worldwide. As an important type of desert vegetation, herbaceous plants have long been acknowledged for their important ecological functions. We focus on the dune-scale distribution pattern of herbaceous plants and their relationship with the environment. During the early summer of 2010, the herbaceous plant density, coverage, aboveground biomass and eighteen environmental factors were surveyed from 214 plots (5m×5m) across two linear sand dunes (220m×110m) located in the Gurbantunggut Desert, China, a typical saline-alkali desert in Central Asia. Data were analyzed using univariate, ordination, and geostatistical techniques. Three vegetation variables represent a significant clumped distribution (P<0.01) across the entire study site. Obvious differences were observed among different slope positions/transects, with the lowest values observed at the summit. Geostatistics indicated that all of the variables showed a moderate spatial dependence and obvious zonal distribution along the sand dunes. The ranges (lag distance) of density (32.2m) and coverage (33.5m) were close to the average width (31.4m) of the transects. The biomass range (74.1m) was almost equal to the average width (75m) of the sand dunes. Pearson's correlation analysis and nonmetric multidimensional scaling analysis consistently demonstrated that the distributions of herbs on sand dunes were dominantly influenced by sand dune topography (slope position, convexity, and relative height), soil nutrients (total nitrogen and phosphorus) and deep-rooted shrubbery (Ephedra distachya). Compared to large, mobile and steep sand dunes, low, fixed and gentle sand dunes contribute to herbaceous plant abundance and distribution as well as the stability maintenance of the whole desert ecosystem.

  18. Facilitation by a Spiny Shrub on a Rhizomatous Clonal Herbaceous in Thicketization-Grassland in Northern China: Increased Soil Resources or Shelter from Herbivores

    Directory of Open Access Journals (Sweden)

    Saixiyala

    2017-05-01

    Full Text Available The formation of fertility islands by shrubs increases soil resources heterogeneity in thicketization-grasslands. Clonal plants, especially rhizomatous or stoloniferous clonal plants, can form large clonal networks and use heterogeneously distributed resources effectively. In addition, shrubs, especially spiny shrubs, may also provide herbaceous plants with protection from herbivores, acting as ‘shelters’. The interaction between pre-dominated clonal herbaceous plants and encroaching shrubs remains unclear in thicketization-grassland under grazing pressure. We hypothesized that clonal herbaceous plants can be facilitated by encroached shrubs as a ‘shelter from herbivores’ and/or as an ‘increased soil resources’ under grazing pressure. To test this hypothesis, a total of 60 quadrats were chosen in a thicket-grassland in northern China that was previously dominated by Leymus chinensis and was encroached upon by the spiny leguminous plant Caragana intermedia. The soil and plant traits beneath and outside the shrub canopies were sampled, investigated and contrasted with an enclosure. The soil organic matter, soil total nitrogen and soil water content were significantly higher in the soil beneath the shrub canopies than in the soil outside the canopies. L. chinensis beneath the shrub canopies had significantly higher plant height, single shoot biomass, leaf length and width than outside the shrub canopies. There were no significantly differences between plant growth in enclosure and outside the shrub canopies. These results suggested that under grazing pressure in a grassland undergoing thicketization, the growth of the rhizomatous clonal herbaceous plant L. chinensis was facilitated by the spiny shrub C. intermedia as a ‘shelter from herbivores’ more than through ‘increased soil resources’. We propose that future studies should focus on the community- and ecosystem-level impacts of plant clonality.

  19. Ecosystem Carbon Stock Influenced by Plantation Practice: Implications for Planting Forests as a Measure of Climate Change Mitigation

    Science.gov (United States)

    Liao, Chengzhang; Luo, Yiqi; Fang, Changming; Li, Bo

    2010-01-01

    Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha−1 in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age (plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation. PMID:20523733

  20. Ecosystem carbon stock influenced by plantation practice: implications for planting forests as a measure of climate change mitigation.

    Directory of Open Access Journals (Sweden)

    Chengzhang Liao

    Full Text Available Uncertainties remain in the potential of forest plantations to sequestrate carbon (C. We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests. Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha(-1 in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age ( or = 25 years, stand types (broadleaved vs. coniferous and deciduous vs. evergreen, tree species origin (native vs. exotic of plantations, land-use history (afforestation vs. reforestation and site preparation for plantations (unburnt vs. burnt, and study regions (tropic vs. temperate. The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation.

  1. In situ measurement of dissolved methane and carbon dioxide in freshwater ecosystems by off-axis integrated cavity output spectroscopy.

    Science.gov (United States)

    Gonzalez-Valencia, Rodrigo; Magana-Rodriguez, Felipe; Gerardo-Nieto, Oscar; Sepulveda-Jauregui, Armando; Martinez-Cruz, Karla; Anthony, Katey Walter; Baer, Doug; Thalasso, Frederic

    2014-10-07

    A novel low-cost method for the combined, real-time, and in situ determination of dissolved methane and carbon dioxide concentrations in freshwater ecosystems was designed and developed. This method is based on the continuous sampling of water from a freshwater ecosystem to a gas/liquid exchange membrane. Dissolved gas is transferred through the membrane to a continuous flow of high purity nitrogen, which is then measured by an off-axis integrated cavity output spectrometer (OA-ICOS). This method, called M-ICOS, was carefully tested in a laboratory and was subsequently applied to four lakes in Mexico and Alaska with contrasting climates, ecologies, and morphologies. The M-ICOS method allowed for the determination of dissolved methane and carbon dioxide concentrations with a frequency of 1 Hz and with a method detection limit of 2.76 × 10(-10) mol L(-1) for methane and 1.5 × 10(-7) mol L(-1) for carbon dioxide. These detection limits are below saturated concentrations with respect to the atmosphere and significantly lower than the minimum concentrations previously reported in lakes. The method is easily operable by a single person from a small boat, and the small size of the suction probe allows the determination of dissolved gases with a minimized impact on shallow freshwater ecosystems.

  2. Ecosystem carbon stock influenced by plantation practice: implications for planting forests as a measure of climate change mitigation.

    Science.gov (United States)

    Liao, Chengzhang; Luo, Yiqi; Fang, Changming; Li, Bo

    2010-05-27

    Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha(-1) in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age ( or = 25 years), stand types (broadleaved vs. coniferous and deciduous vs. evergreen), tree species origin (native vs. exotic) of plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation.

  3. Measuring social-ecological dynamics behind the generation of ecosystem services.

    Science.gov (United States)

    Andersson, E; Barthel, S; Ahrné, K

    2007-07-01

    The generation of ecosystem services depends on both social and ecological features. Here we focus on management, its ecological consequences, and social drivers. Our approach combined (1) quantitative surveys of local species diversity and abundance of three functional groups of ecosystem service providers (pollinators, seed dispersers, and insectivores) with (2) qualitative studies of local management practices connected to these services and their underlying social mechanisms, i.e., institutions, local ecological knowledge, and a sense of place. It focused on the ecology of three types of green areas (allotment gardens, cemeteries, and city parks) in the city of Stockholm, Sweden. These are superficially similar but differ considerably in their management. Effects of the different practices could be seen in the three functional groups, primarily as a higher abundance of pollinators in the informally managed allotment gardens and as differences in the composition of seed dispersers and insectivores. Thus, informal management, which is normally disregarded by planning authorities, is important for ecosystem services in the urban landscape. Furthermore, we suggest that informal management has an important secondary function: It may be crucial during periods of instability and change as it is argued to promote qualities with potential for adaptation. Allotment gardeners seem to be the most motivated managers, something that is reflected in their deeper knowledge and can be explained by a sense of place and management institutions. We propose that co-management would be one possible way to infuse the same positive qualities into all management and that improved information exchange between managers would be one further step toward ecologically functional urban landscapes.

  4. Net ecosystem exchange and energy fluxes measured with the eddy covariance technique in a western Siberian bog

    Science.gov (United States)

    Alekseychik, Pavel; Mammarella, Ivan; Karpov, Dmitry; Dengel, Sigrid; Terentieva, Irina; Sabrekov, Alexander; Glagolev, Mikhail; Lapshina, Elena

    2017-08-01

    Very few studies of ecosystem-atmosphere exchange involving eddy covariance data have been conducted in Siberia, with none in the western Siberian middle taiga. This work provides the first estimates of carbon dioxide (CO2) and energy budgets in a typical bog of the western Siberian middle taiga based on May-August measurements in 2015. The footprint of measured fluxes consisted of a homogeneous mixture of tree-covered ridges and hollows with the vegetation represented by typical sedges and shrubs. Generally, the surface exchange rates resembled those of pine-covered bogs elsewhere. The surface energy balance closure approached 100 %. Net CO2 uptake was comparatively high, summing up to 202 gC m-2 for the four measurement months, while the Bowen ratio was seasonally stable at 28 %. The ecosystem turned into a net CO2 source during several front passage events in June and July. The periods of heavy rain helped keep the water table at a sustainably high level, preventing a usual drawdown in summer. However, because of the cloudy and rainy weather, the observed fluxes might rather represent the special weather conditions of 2015 than their typical magnitudes.

  5. Irrigation Strategies and Crop Breeding As Complementary Measures for Improved Water Management and Ecosystem Services

    Science.gov (United States)

    Vico, G.; Manzoni, S.; Weih, M.; Porporato, A. M.

    2014-12-01

    The projected population growth and changes in climate and dietary habits will further increase the pressure on water resources globally. Within precision farming, a host of technical solutions has been developed to reduce water consumption for agricultural uses. Examples are the shift from scheduled to demand-based irrigation and the use of sophisticated water distribution techniques. The next frontier for a more sustainable agriculture is the combination of reduced water requirements with enhanced ecosystem services. Currently, staple grains are obtained from annuals crops. Enhanced ecosystem services could be obtained shifting from annual to perennial crops, obtained by means of targeted breeding. In fact, perennial plants, with their continuous soil cover and the higher allocation of resources to the below ground, contribute to the reduction of soil erosion, water and nutrient losses, while enhancing carbon sequestration in the root zone. We explore here the implications for water management at the field- to farm-scale of both improved irrigation methods and targeted breeding. A probabilistic description of the soil water balance and crop development is employed to quantify water requirements and yields and their inter-annual variability, as a function of rainfall patterns, soil and crop features. Optimal irrigation strategies are thus defined in terms of maximization of yield and minimization of required irrigation volumes and their inter-annual variability. The probabilistic model is parameterized based on an extensive meta-analysis of traits of co-generic annual and perennial species (including both selected and wild species) to explore the consequences for water requirements of shifting from annual to perennial crops under current and future climates. The larger and more developed roots of perennial crops may allow a better exploitation of soil water resources than annual species. At the same time, perennial crops may require adequate water supply for

  6. Design rules for successful governmental payments for ecosystem services: Taking agri-environmental measures in Germany as an example.

    Science.gov (United States)

    Meyer, Claas; Reutter, Michaela; Matzdorf, Bettina; Sattler, Claudia; Schomers, Sarah

    2015-07-01

    In recent years, increasing attention has been paid to financial environmental policy instruments that have played important roles in solving agri-environmental problems throughout the world, particularly in the European Union and the United States. The ample and increasing literature on Payments for Ecosystem Services (PES) and agri-environmental measures (AEMs), generally understood as governmental PES, shows that certain single design rules may have an impact on the success of a particular measure. Based on this research, we focused on the interplay of several design rules and conducted a comparative analysis of AEMs' institutional arrangements by examining 49 German cases. We analyzed the effects of the design rules and certain rule combinations on the success of AEMs. Compliance and noncompliance with the hypothesized design rules and the success of the AEMs were surveyed by questioning the responsible agricultural administration and the AEMs' mid-term evaluators. The different rules were evaluated in regard to their necessity and sufficiency for success using Qualitative Comparative Analysis (QCA). Our results show that combinations of certain design rules such as environmental goal targeting and area targeting conditioned the success of the AEMs. Hence, we generalize design principles for AEMs and discuss implications for the general advancement of ecosystem services and the PES approach in agri-environmental policies. Moreover, we highlight the relevance of the results for governmental PES program research and design worldwide.

  7. Herbaceous standing crop in relation to surface and subsurface rockiness

    Directory of Open Access Journals (Sweden)

    M. C. Rutherford

    1983-12-01

    Full Text Available A study, carried out in non-wooded parts of savanna and in desert grassland, demonstrated that herbaceous standing crop can decrease with increasing surface rock cover. However, such decreases corresponded more directly to a soil volumetric decrease than to a decrease in soil surface area per se. The relationship was also found to depend strongly on subsurface rock weathering patterns which may reverse the indicated relationship between standing crop and surface rock cover. The application of surface rock cover data without regard to profile stoniness, is, therefore, likely to be of limited use for comparing plant production across different geological substrates. The role of different rock types in giving rise to soils of different fertility with corresponding plant responses, was also indicated by the data. Sensitivity of plant standing crop to surface rock cover was possibly dependent on mean annual rainfall, but further data are required. The interpretation of aboveground standing crop data in terms of aboveground annual production is briefly discussed.

  8. ASPECTS OF REHABILITATION OF WASTE DUMPS USING HERBACEOUS PLANTS

    Directory of Open Access Journals (Sweden)

    Smaranda Masu

    2015-05-01

    Full Text Available There are many arguments that underlie research on rehabilitation of large areas of land that were set aside from the agricultural circuit and became heaps of storage for inert waste materials like bottom and boiler slag and fly ash. On the other hand result of biological materials with potential for land recycling i.e. sewage sludge. On the dumps of boiler slag composed of particles of 2-3 mm was gradually installed a layer of grass with the help of sewage sludge as a fertilizing agent and microbial activity stimulating agent, based on an extract of brown seaweed EKO GEA Slovenia. In the second year the amount of biomass harvested was 2 to 2.9 times higher than in the first year of cultivation. Moreover plants not harvested in the second year of culture bore fruit. Also, the root network strongly stabilized the slag and boiler ash particles against land spreading. Rapid and effective rehabilitation of the landscape destroyed was achieved with the use of herbaceous crops of the species Lolium perenne. Monitoring bioaccumulation of heavy metals i.e. Cd, Cr, Cu, Ni, Pb, Ni, Zn, etc. in aerial plant tissue was needed to decide the sector where the biomass harvested from inert waste dump covered with vegetation.

  9. Tolerance of herbaceous summer legumes of temporary waterlogging

    Directory of Open Access Journals (Sweden)

    Elsa M. Ciotti

    2014-09-01

    Full Text Available A greenhouse study to evaluate adaptation of 4 herbaceous summer legumes to temporary waterlogging was conducted.  Species evaluated were Desmanthus virgatus and Aeschynomene americana in their vegetative stage, and Macroptilium lathyroides and M. atropurpureum in both vegetative and reproductive stages.  The experimental design was randomized blocks with 5 replications and treatments were:  T0, control; T1, saturation by capillary movement placing pots in buckets of 5 L with 10 cm of permanent water; and T2, flooding, placing pots in buckets of 10 L and a layer of water 5 cm above the soil.  The duration of the water treatments was 7 days. Waterlogging did not affect shoot or root biomass production nor nodulation in A. americana, whereas D. virgatus had its highest dry matter production in saturated soil (T1.  In M. lathyroides flooding tolerance was more evident in the reproductive than in the vegetative stage, probably due to more production of adventitious roots and formation of aerenchymatic tissue.  Macroptilium atropurpureum showed adaptation to temporary flooding.  Survival and quick recovery of these species would confirm their potential as forages for temporarily waterlogged soils.Keywords: Forage legumes, flooding, Aeschynomene americana, Desmanthus virgatus, Macroptilium lathyroides, Northeast Argentina.DOI: 10.17138/TGFT(2278-286

  10. Tolerance of herbaceous summer legumes of temporary waterlogging

    Directory of Open Access Journals (Sweden)

    Elsa M. Ciotti

    2014-09-01

    Full Text Available A greenhouse study to evaluate adaptation of 4 herbaceous summer legumes to temporary waterlogging was conducted.  Species evaluated were Desmanthus virgatus and Aeschynomene americana in their vegetative stage, and Macroptilium lathyroides and M. atropurpureum in both vegetative and reproductive stages.  The experimental design was randomized blocks with 5 replications and treatments were:  T0, control; T1, saturation by capillary movement placing pots in buckets of 5 L with 10 cm of permanent water; and T2, flooding, placing pots in buckets of 10 L and a layer of water 5 cm above the soil.  The duration of the water treatments was 7 days. Waterlogging did not affect shoot or root biomass production nor nodulation in A. americana, whereas D. virgatus had its highest dry matter production in saturated soil (T1.  In M. lathyroides flooding tolerance was more evident in the reproductive than in the vegetative stage, probably due to more production of adventitious roots and formation of aerenchymatic tissue.  Macroptilium atropurpureum showed adaptation to temporary flooding.  Survival and quick recovery of these species would confirm their potential as forages for temporarily waterlogged soils.Keywords: Forage legumes, flooding, Aeschynomene americana, Desmanthus virgatus, Macroptilium lathyroides, Northeast Argentina.DOI: 10.17138/TGFT(2278-286

  11. Simkin et al. 2016 PNAS data on herbaceous species richness and associated plot and covariate information

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes the geographic location (lat/lon) for 15,136 plots, as well as the herbaceous species richness, climate, soil pH, and other variables related...

  12. Herbaceous forage and selection patterns by ungulates across varying herbivore assemblages in a South African savanna

    NARCIS (Netherlands)

    Treydte, A.C.; Baumgartner, S.; Heitkonig, I.M.A.; Grant, C.C.; Getz, W.M.

    2013-01-01

    Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African sav

  13. The cost of silage harvest and transport systems for herbaceous crops

    Energy Technology Data Exchange (ETDEWEB)

    Turhollow, A.; Downing, M. [Oak Ridge National Lab., TN (United States); Butler, J. [Butler (James), Tifton, GA (United States)

    1996-12-31

    Some of the highest yielding herbaceous biomass crops are thick- stemmed species. Their relatively high moisture content necessitates they be handled and stored as silage rather than hay bales or modules. This paper presents estimated costs of harvesting and transporting herbaceous crops as silage. Costs are based on an engineering- economic approach. Equipment costs are estimated by combining per hour costs with the hours required to complete the operation. Harvest includes severing, chopping, and blowing stalks into a wagon or truck.

  14. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    Science.gov (United States)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    Although maize is the second most important crop worldwide, and the most important C4 crop, no study on biogenic volatile organic compounds (BVOCs) has yet been conducted on this crop at ecosystem scale and over a whole growing season. This has led to large uncertainties in cropland BVOC emission estimations. This paper seeks to fill this gap by presenting, for the first time, BVOC fluxes measured in a maize field at ecosystem scale (using the disjunct eddy covariance by mass scanning technique) over a whole growing season in Belgium. The maize field emitted mainly methanol, although exchanges were bi-directional. The second most exchanged compound was acetic acid, which was taken up mainly in the growing season. Bi-directional exchanges of acetaldehyde, acetone and other oxygenated VOCs also occurred, whereas the terpenes, benzene and toluene exchanges were small, albeit significant. Surprisingly, BVOC exchanges were of the same order of magnitude on bare soil and on well developed vegetation, suggesting that soil is a major BVOC reservoir in agricultural ecosystems. Quantitatively, the maize BVOC emissions observed were lower than those reported in other maize, crops and grasses studies. The standard emission factors (SEFs) estimated in this study (231 ± 19 µg m-2 h-1 for methanol, 8 ± 5 µg m-2 h-1 for isoprene and 4 ± 6 µg m-2 h-1 for monoterpenes) were also much lower than those currently used by models for C4 crops, particularly for terpenes. These results suggest that maize fields are small BVOC exchangers in north-western Europe, with a lower BVOC emission impact than that modelled for growing C4 crops in this part of the world. They also reveal the high variability in BVOC exchanges across world regions for maize and suggest that SEFs should be estimated for each region separately.

  15. Multi-Polarization ASAR Backscattering from Herbaceous Wetlands in Poyang Lake Region, China

    Directory of Open Access Journals (Sweden)

    Huiyong Sang

    2014-05-01

    Full Text Available Wetlands are one of the most important ecosystems on Earth. There is an urgent need to quantify the biophysical parameters (e.g., plant height, aboveground biomass and map total remaining areas of wetlands in order to evaluate the ecological status of wetlands. In this study, Environmental Satellite/Advanced Synthetic Aperture Radar (ENVISAT/ASAR dual-polarization C-band data acquired in 2005 is tested to investigate radar backscattering mechanisms with the variation of hydrological conditions during the growing cycle of two types of herbaceous wetland species, which colonize lake borders with different elevation in Poyang Lake region, China. Phragmites communis (L. Trin. is semi-aquatic emergent vegetation with vertical stem and blade-like leaves, and the emergent Carex spp. has rhizome and long leaves. In this study, the potential of ASAR data in HH-, HV-, and VV-polarization in mapping different wetland types is examined, by observing their dynamic variations throughout the whole flooding cycle. The sensitivity of ASAR backscattering coefficients to vegetation parameters of plant height, fresh and dry biomass, and vegetation water content is also analyzed for Phragmites communis (L. Trin. and Carex spp. The research for Phragmites communis (L. Trin. shows that HH polarization is more sensitive to plant height and dry biomass than HV polarization. ASAR backscattering coefficients are relatively less sensitive to fresh biomass, especially in HV polarization. However, both are highly dependent on canopy water content. In contrast, the dependence of HH- and HV- backscattering from Carex community on vegetation parameters is poor, and the radar backscattering mechanism is controlled by ground water level.

  16. Mediterranean dunes on the go: Evidence from a short term study on coastal herbaceous vegetation

    Science.gov (United States)

    Prisco, Irene; Stanisci, Angela; Acosta, Alicia T. R.

    2016-12-01

    Detailed monitoring studies on permanent sites are a promising tool for an accurate evaluation of short, medium or long term vegetation dynamics. This work aims to evaluate short-term changes in coastal dune herbaceous plant species and EU Habitats through a multi-temporal analysis using permanent vegetation transects. In particular, (I) we analyze changes in species richness of coastal habitats; (II) we identify changes in plant cover of selected focal plants; and (III) we relate the changes to selected climatic variables and erosion/accretion processes. We selected one of the Italian's peninsula best preserved coastal dune areas (ca. 50 km along the Adriatic sea) with a relatively homogeneous coastal zonation and low anthropic pressure but with different erosion/accretion processes. We explored changes in richness over time using generalized linear models (GLMs). We identified different ecological guilds: focal, ruderal and alien plant species and investigated temporal trends in these guilds' species richness. We also applied GLMs to determine how plant cover of the most important focal species have changed over time. Overall, in this study we observed that the influence of climatic variables was relatively small. However, we found remarkable different trends in response to erosion/accretion processes both at community and at species level. Thus, our results highlight the importance of coastal dynamics in preserving not only coastal vegetation zonation, but also species richness and focal species cover. Moreover, we identified the dune grasslands as the most sensitive habitat for detecting the influence of climatic variables throughout a short term monitoring survey. Information from this study provides useful insights for detecting changes in vegetation, for establishing habitat protection priorities and for improving conservation efforts for these fragile ecosystems.

  17. High temporal resolution ecosystem CH4, CO2 and H2O flux data measured with a novel chamber technique

    Science.gov (United States)

    Steenberg Larsen, Klaus; Riis Christiansen, Jesper

    2016-04-01

    Soil-atmosphere exchange of greenhouse gases (GHGs) is commonly measured with closed static chambers (Pihlatie et al., 2013) with off-site gas chromatographic (GC) analysis for CH4 and N2O. Static chambers are widely used to observe in detail the effect of experimental manipulations, like climate change experiments, on GHG exchange (e.g. Carter et al., 2012). However, the low sensitivity of GC systems necessitates long measurement times and manual sampling, which increases the disturbance of the exchange of GHGs and leads to potential underestimation of fluxes (Christiansen et al., 2011; Creelman et al., 2013). The recent emergence of field proof infrared lasers using cavity ring-down spectroscopy (CRDS) have increased frequency and precision of concentration measurements and enabled better estimates of GHG fluxes (Christiansen et al., 2015) due to shorter chamber enclosure times. This minimizes the negative impact of the chamber enclosure on the soil-atmosphere gas exchange rate. Secondly, an integral aspect of understanding GHG exchange in terrestrial ecosystem is to achieve high temporal coverage. This is needed to capture the often dynamic behavior where fluxes can change rapidly over the course of days or even a few hours in response to e.g. rain events. Consequently, low temporal coverage in measurements of GHG exchange have in many past investigations led to highly uncertain annual budgets which severely limits our understanding of the ecosystem processes interacting with the climate system through GHG exchange. Real-time field measurements at high temporal resolution are needed to obtain a much more detailed understanding of the processes governing ecosystem CH4 exchange as well as for better predicting the effects of climate and environmental changes. We combined a state-of-the-art field applicable CH4 sensor (Los Gatos UGGA) with a newly developed ecosystem-level automatic chamber controlled by a LI-COR 8100/8150 system. The chamber is capable of

  18. Size-based hydroacoustic measures of within-season fish abundance in a boreal freshwater ecosystem.

    Directory of Open Access Journals (Sweden)

    Riley A Pollom

    Full Text Available Eleven sequential size-based hydroacoustic surveys conducted with a 200 kHz split-beam transducer during the summers of 2011 and 2012 were used to quantify seasonal declines in fish abundance in a boreal reservoir in Manitoba, Canada. Fish densities were sufficiently low to enable single target resolution and tracking. Target strengths converted to log2-based size-classes indicated that smaller fish were consistently more abundant than larger fish by a factor of approximately 3 for each halving of length. For all size classes, in both years, abundance (natural log declined linearly over the summer at rates that varied from -0.067 x day(-1 for the smallest fish to -0.016 x day(-1 for the largest (R2 = 0.24-0.97. Inter-annual comparisons of size-based abundance suggested that for larger fish (>16 cm, mean winter decline rates were an order of magnitude lower (-0.001 x day(-1 and overall survival higher (71% than in the main summer fishing season (mean loss rate -0.038 x day(-1; survival 33%. We conclude that size-based acoustic survey methods have the potential to assess within-season fish abundance dynamics, and may prove useful in long-term monitoring of productivity and hence management of boreal aquatic ecosystems.

  19. Continuous measurement of CO2 flux through the snowpack in a dwarf bamboo ecosystem on Rishiri Island, Hokkaido, Japan

    Science.gov (United States)

    Zhu, Chunmao; Nakayama, Momoko; Yoshikawa Inoue, Hisayuki

    2014-09-01

    To investigate the dynamics and environmental drivers of CO2 flux through the winter snowpack in a dwarf bamboo ecosystem (Hokkaido, northeast Japan), we constructed an automated sampling system to measured CO2 concentrations at five different levels in the snowpack, from the base to the upper snow surface. Using a gas diffusion approach, we estimated an average apparent soil CO2 flux of 0.26 μmol m-2 s-1 during the snow season (December-April); temporally, the CO2 flux increased until mid-snow season, but showed no clear trend thereafter; late-season snow-melting events resulted in rapid decreases in apparent CO2 flux values. Air temperature and subnivean CO2 flux exhibited a positive linear relationship. After eliminating the effects of wind pumping, we estimated the actual soil CO2 flux (0.41 μmol m-2 s-1) to be 54% larger than the apparent flux. This study provides new constraints on snow-season carbon emissions in a dwarf bamboo ecosystem in northeast Asia.

  20. Monetary accounting of ecosystem services

    NARCIS (Netherlands)

    Remme, R.P.; Edens, Bram; Schröter, Matthias; Hein, Lars

    2015-01-01

    Ecosystem accounting aims to provide a better understanding of ecosystem contributions to the economy in a spatially explicit way. Ecosystem accounting monitors ecosystem services and measures their monetary value using exchange values consistent with the System of National Accounts (SNA). We pil

  1. Monetary accounting of ecosystem services

    NARCIS (Netherlands)

    Remme, R.P.; Edens, Bram; Schröter, Matthias; Hein, Lars

    2015-01-01

    Ecosystem accounting aims to provide a better understanding of ecosystem contributions to the economy in a spatially explicit way. Ecosystem accounting monitors ecosystem services and measures their monetary value using exchange values consistent with the System of National Accounts (SNA). We

  2. Is digital cover photography a viable method for measuring leaf index for phenological research in closed forest ecosystems?

    Science.gov (United States)

    Felts, E. S.; Sonnentag, O.; Ryu, Y.; Macfarlane, C.; Hufkens, K.; Keenan, T. F.; Friedl, M. A.; Richardson, A. D.

    2011-12-01

    The use of the LAI-2000 plant canopy analyzer as instrument for calculating plant area index (PAI), and ultimately leaf area index (LAI), based on hemispherical gap-fraction measurements has been established through past studies. Ideally, these measurements are taken under diffuse light, which restricts their application to overcast conditions or short time windows during dusk and dawn. A promising and less restrictive alternative is digital cover photography (DCP), which provides estimates of crown porosity (φ), and foliage (ff) and crown cover fractions (fc). From these, PAI can be calculated, which can then be corrected for the influence of woody canopy elements to obtain LAI. The method has been developed and tested in Eucalyptus forests and oak-savanna woodland, i.e. in open ecosystems where enough light can penetrate the canopy for sufficient scene illumination. This research seeks to explore the viability of DCP as a method of obtaining PAI and LAI for phenological research in closed forest ecosystems such as temperate broadleaf deciduous forests, where limited scene illumination especially under fully developed canopies and the seasonally changing influence of woody canopy elements to φ, ff and fc might pose methodological challenges. To test the performance of DCP under these conditions, weekly imaging of 33 long-term incremental biomass plots at a temperate broadleaf-deciduous-dominated forest (Harvard Forest) was undertaken with a digital single-lens reflex camera (Pentax K100D). To examine the role of changing scene illumination at different canopy development stages, the images were acquired in RAW format to allow maximum control over image exposure in the post-processing. Using a range of different exposure settings, DCP-based PAI estimates were then compared to PAI estimates obtained from gap-fraction measurements made with the LAI-2000 instrument (recomputed using only the first 7° ring) at the same plots, and with canopy greenness obtained with

  3. Constraining ecosystem model with adaptive Metropolis algorithm using boreal forest site eddy covariance measurements

    Science.gov (United States)

    Mäkelä, Jarmo; Susiluoto, Jouni; Markkanen, Tiina; Aurela, Mika; Järvinen, Heikki; Mammarella, Ivan; Hagemann, Stefan; Aalto, Tuula

    2016-12-01

    We examined parameter optimisation in the JSBACH (Kaminski et al., 2013; Knorr and Kattge, 2005; Reick et al., 2013) ecosystem model, applied to two boreal forest sites (Hyytiälä and Sodankylä) in Finland. We identified and tested key parameters in soil hydrology and forest water and carbon-exchange-related formulations, and optimised them using the adaptive Metropolis (AM) algorithm for Hyytiälä with a 5-year calibration period (2000-2004) followed by a 4-year validation period (2005-2008). Sodankylä acted as an independent validation site, where optimisations were not made. The tuning provided estimates for full distribution of possible parameters, along with information about correlation, sensitivity and identifiability. Some parameters were correlated with each other due to a phenomenological connection between carbon uptake and water stress or other connections due to the set-up of the model formulations. The latter holds especially for vegetation phenology parameters. The least identifiable parameters include phenology parameters, parameters connecting relative humidity and soil dryness, and the field capacity of the skin reservoir. These soil parameters were masked by the large contribution from vegetation transpiration. In addition to leaf area index and the maximum carboxylation rate, the most effective parameters adjusting the gross primary production (GPP) and evapotranspiration (ET) fluxes in seasonal tuning were related to soil wilting point, drainage and moisture stress imposed on vegetation. For daily and half-hourly tunings the most important parameters were the ratio of leaf internal CO2 concentration to external CO2 and the parameter connecting relative humidity and soil dryness. Effectively the seasonal tuning transferred water from soil moisture into ET, and daily and half-hourly tunings reversed this process. The seasonal tuning improved the month-to-month development of GPP and ET, and produced the most stable estimates of water use

  4. Net ecosystem carbon exchange in three contrasting Mediterranean ecosystems – the effect of drought

    Directory of Open Access Journals (Sweden)

    T. S. David

    2007-09-01

    Full Text Available Droughts reduce gross primary production (GPP and ecosystem respiration (Reco, contributing to most of the inter-annual variability in terrestrial carbon sequestration. In seasonally dry climates (Mediterranean, droughts result from reductions in annual rainfall and changes in rain seasonality. We compared carbon fluxes measured by the eddy covariance technique in three contrasting ecosystems in southern Portugal: an evergreen oak woodland (savannah-like with ca.~21% tree crown cover, a grassland dominated by herbaceous annuals and a coppiced short-rotation eucalyptus plantation. During the experimental period (2003–2006 the eucalyptus plantation was always the strongest sink for carbon: net ecosystem exchange rate (NEE between −861 and −399 g C m−2 year−1. The oak woodland and the grassland were much weaker sinks for carbon: NEE varied in the oak woodland between −140 and −28 g C m−2 year−1 and in the grassland between −190 and +49 g C m−2 year−1. The eucalyptus stand had higher GPP and a lower proportion of GPP spent in respiration than the other systems. The higher GPP resulted from high leaf area duration (LAD, as a surrogate for the photosynthetic photon flux density absorbed by the canopy. The eucalyptus had also higher rain use efficiency (GPP per unit of rain volume and light use efficiency (the daily GPP per unit incident photosynthetic photon flux density than the other two ecosystems. The effects of a severe drought could be evaluated during the hydrological-year (i.e., from October to September of 2004–2005. Between October 2004 and June 2005 the precipitation was only 40% of the long-term average. In 2004–2005 all ecosystems had GPP lower than in wetter years and carbon sequestration was strongly restricted (less negative NEE. The grassland was a net source of carbon dioxide (+49 g C m−2 year−1. In the oak woodland a large proportion of GPP resulted from carbon assimilated by its annual vegetation

  5. Ecosystem services

    Science.gov (United States)

    Trista Patterson

    2014-01-01

    Since its inception, the ecosystem service approach has stimulated interest from numerous planning, management, and partnership perspectives. To date, however, research that quantifies ecosystem services in the study area (in the form of explicit ecosystem service studies) has been limited. This chapter reviews and synthesizes the concept of ecosystem services,...

  6. Mosses Like It Rough—Growth Form Specific Responses of Mosses, Herbaceous and Woody Plants to Micro-Relief Heterogeneity

    Directory of Open Access Journals (Sweden)

    Carl Beierkuhnlein

    2012-02-01

    Full Text Available Micro-relief heterogeneity can lead to substantial variability in microclimate and hence niche opportunities on a small scale. We explored the relationship between plant species richness and small-scale heterogeneity of micro-relief on the subtropical island of La Palma, Canary Islands. Overall, we sampled 40 plots in laurel and pine forests at four altitudinal bands. Species richness was recorded separately for various growth forms (i.e., mosses, herbaceous and woody plants. Site conditions such as altitude, slope, aspect, and tree density were measured. Micro-relief heterogeneity was characterized by surface structure and a subsequently derived surface heterogeneity index. The effect of micro-relief heterogeneity on species richness was analysed by means of linear mixed effect models and variance partitioning. Effects of micro-relief heterogeneity on species richness varied considerably between growth forms. While moss richness was affected significantly by micro-relief heterogeneity, herbaceous and woody plants richness responded mainly to larger-scale site conditions such as aspect and tree density. Our results stress the importance of small-scale relief heterogeneity for the explanation of spatial patterns of species richness. This poses new challenges as small-scale heterogeneity is largely underrepresented, e.g. with regard to its application in species distribution models.

  7. Towards a standardized processing of Net Ecosystem Exchange measured with eddy covariance technique: algorithms and uncertainty estimation

    Directory of Open Access Journals (Sweden)

    D. Papale

    2006-01-01

    Full Text Available Eddy covariance technique to measure CO2, water and energy fluxes between biosphere and atmosphere is widely spread and used in various regional networks. Currently more than 250 eddy covariance sites are active around the world measuring carbon exchange at high temporal resolution for different biomes and climatic conditions. In this paper a new standardized set of corrections is introduced and the uncertainties associated with these corrections are assessed for eight different forest sites in Europe with a total of 12 yearly datasets. The uncertainties introduced on the two components GPP (Gross Primary Production and TER (Terrestrial Ecosystem Respiration are also discussed and a quantitative analysis presented. Through a factorial analysis we find that generally, uncertainties by different corrections are additive without interactions and that the heuristic u*-correction introduces the largest uncertainty. The results show that a standardized data processing is needed for an effective comparison across biomes and for underpinning inter-annual variability. The methodology presented in this paper has also been integrated in the European database of the eddy covariance measurements.

  8. Net ecosystem exchange and energy fluxes measured with the eddy covariance technique in a western Siberian bog

    Directory of Open Access Journals (Sweden)

    P. Alekseychik

    2017-08-01

    Full Text Available Very few studies of ecosystem–atmosphere exchange involving eddy covariance data have been conducted in Siberia, with none in the western Siberian middle taiga. This work provides the first estimates of carbon dioxide (CO2 and energy budgets in a typical bog of the western Siberian middle taiga based on May–August measurements in 2015. The footprint of measured fluxes consisted of a homogeneous mixture of tree-covered ridges and hollows with the vegetation represented by typical sedges and shrubs. Generally, the surface exchange rates resembled those of pine-covered bogs elsewhere. The surface energy balance closure approached 100 %. Net CO2 uptake was comparatively high, summing up to 202 gC m−2 for the four measurement months, while the Bowen ratio was seasonally stable at 28 %. The ecosystem turned into a net CO2 source during several front passage events in June and July. The periods of heavy rain helped keep the water table at a sustainably high level, preventing a usual drawdown in summer. However, because of the cloudy and rainy weather, the observed fluxes might rather represent the special weather conditions of 2015 than their typical magnitudes.

  9. Variations in soil properties, species composition, diversity and biomass of herbaceous species due to ruminant dung residue in a seasonally dry tropical environment of India

    Directory of Open Access Journals (Sweden)

    Preeti Verma

    2015-05-01

    Full Text Available Ruminants directly or indirectly influence nutrient cycling and vegetation structure in grassland ecosystems. We assessed the impact of natural cattle dung deposition on soil attributes and the resulting effects on species composition, species diversity and biomass of herbaceous vegetation in a natural grassland in the seasonally dry tropical environment of Banaras Hindu University, India. For this 72 plots of 1 × 1 m [12 locations × 2 treatments (dung residue and control × 3 replicates] were selected in January 2013 and soil and vegetation samples collected. A total of 74 species belonging to 66 genera and 25 families were recorded. Principal Component Analysis (PCA ordination revealed that the dung residue (DP and control (CP plots were distinctly different in terms of soil attributes and species composition. The k-dominance plot showed greater species diversity in DPs than CPs, with higher soil nutrients and moisture and lower soil pH in DPs than CPs. Similarly, DPs showed more herbaceous species and greater biomass than CPs. This trend can be explained by the positive responses of forbs, erect plants, annuals, large-statured, non-native and non-leguminous species to dung residue, while increased biomass can be partly due to cattle preferentially not grazing areas adjacent to a dung pat. Overall, the study showed that deposition of dung during grazing by cattle stimulates growth of pasture species and increases species diversity. Therefore cattle dung could be used as a sustainable alternative to chemical fertilizers to manage soil pH, species composition and diversity, and forage production in the seasonally dry tropical grasslands of India, which are nutrient- and moisture-limited.Keywords: Animal manure, herbaceous vegetation, plant functional attributes, soil pH, species change.DOI: 10.17138/TGFT(3112-128 

  10. Relationship between Major Mineral Nutrient Elements Contents and Flower Colors of Herbaceous Peony (Paeonia Lactiflora Pall.

    Directory of Open Access Journals (Sweden)

    Chengzhong Li

    2015-02-01

    Full Text Available Herbaceous peony (Paeonia lactiflora Pall. is a famous ornamental plant with bright flowers and lush leaves. The flower petal can be used as a fragrant food additive. Understanding the mineral nutrient contents in P. lactiflora is necessary for guiding its cultivation practices as well as its use as a food additive. In this study, we investigated the mineral contents including Calcium (Ca, Potassium (K, Magnesium (Mg, Copper (Cu, iron (Fe and Zinc (Zn in petals and leaves of 20 selected herbaceous peony cultivars in four groups according to their flower colors and the relationship between major mineral nutrient elements contents and flower colors was assessed. In petals, the contents of minerals were in this order K>Ca>Mg>Fe>Zn>Cu; while in leaves were: Ca>K>Mg>Fe>Zn>Cu. Major element contents in petals and leaves among 4 cultivar groups were different at statistically significant levels. Petals in red or purple have higher amount of most major minerals than those in white or pink colors. The wide range of mineral element contents among cultivars is attributed to genotypic variations. The correlations of major mineral elements in the petals and leaves of herbaceous peony cultivars indicate that mineral ions compete for the same absorption sites. The results provided some scientific support for petal nutrition of herbaceous peony and selecting herbaceous peony flowers with dark colors for edible is feasible.

  11. Responses of herbaceous plants to urban air pollution: effects on growth, phenology and leaf surface characteristics.

    Science.gov (United States)

    Honour, Sarah L; Bell, J Nigel B; Ashenden, Trevor W; Cape, J Neil; Power, Sally A

    2009-04-01

    Vehicle exhaust emissions are a dominant feature of urban environments and are widely believed to have detrimental effects on plants. The effects of diesel exhaust emissions on 12 herbaceous species were studied with respect to growth, flower development, leaf senescence and leaf surface wax characteristics. A diesel generator was used to produce concentrations of nitrogen oxides (NO(x)) representative of urban conditions, in solardome chambers. Annual mean NO(x) concentrations ranged from 77 nl l(-l) to 98 nl l(-1), with NO:NO(2) ratios of 1.4-2.2, providing a good experimental simulation of polluted roadside environments. Pollutant exposure resulted in species-specific changes in growth and phenology, with a consistent trend for accelerated senescence and delayed flowering. Leaf surface characteristics were also affected; contact angle measurements indicated changes in surface wax structure following pollutant exposure. The study demonstrated clearly the potential for realistic levels of vehicle exhaust pollution to have direct adverse effects on urban vegetation.

  12. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    Science.gov (United States)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    Maize is the most important C4 crop worldwide. It is also the second most important crop worldwide (C3 and C4 mixed), and is a dominant crop in some world regions. Therefore, it can potentially influence local climate and air quality through its exchanges of gases with the atmosphere. Among others, biogenic volatile organic compounds (BVOC) are known to influence the atmospheric composition and thereby modify greenhouse gases lifetime and pollutant formation in the atmosphere. However, so far, only two studies have dealt with BVOC exchanges from maize. Moreover, these studies were conducted on a limited range of meteorological and phenological conditions, so that the knowledge of BVOC exchanges by this crop remains poor. Here, we present the first BVOC measurement campaign performed at ecosystem-scale on a maize field during a whole growing season. It was carried out in the Lonzée Terrestrial Observatory (LTO), an ICOS site. BVOC fluxes were measured by the disjunct by mass-scanning eddy covariance technique with a proton transfer reaction mass spectrometer for BVOC mixing ratios measurements. Outstanding results are (i) BVOC exchanges from soil were as important as BVOC exchanges from maize itself; (ii) BVOC exchanges observed on our site were much lower than exchanges observed by other maize studies, even under normalized temperature and light conditions, (iii) they were also lower than those observed on other crops grown in Europe. Lastly (iv), BVOC exchanges observed on our site under standard environmental conditions, i.e., standard emission factors SEF, were much lower than those currently considered by BVOC exchange up-scaling models. From those observations, we deduced that (i) soil BVOC exchanges should be better understood and should be incorporated in terrestrial BVOC exchanges models, and that (ii) SEF for the C4 crop plant functional type cannot be evaluated at global scale but should be determined for each important agronomic and pedo-climatic region

  13. A conceptual framework for an ecosystem services-based assessment of the so-called "emergency stabilization" measures following wildfire

    Science.gov (United States)

    Valente, Sandra; Prats, Sergio; Ribeiro, Cristina; Verheijen, Frank; Fleskens, Luuk; Keizer, Jacob

    2015-04-01

    Wildfires have become a major environmental concern in many Southern European countries over the past few decades. This includes Portugal, where, on average, some 100 000 ha of rural lands are affected by wildfire every year. While policies, laws, plans and public expenditure in Portugal continue to be largely directed towards fire combat and, arguably, to a lesser extent fire prevention, there has only recently been increasing attention for post-fire land management. For example following frequent and several large wildfires during the summer of 2010, so-called emergency stabilization measures were implemented in 16 different burnt areas in northern and central Portugal, using funds of the EU Rural Development Plan in Portugal (PRODER). The measures that were implemented included mulching (i.e. application of a protective layer of organic material), seeding and the construction of log barriers. However, the effectiveness of the implemented measures has not been monitored or otherwise assessed in a systematic manner. In fact, until very recently none of the post-fire emergency stabilization measures contemplated under PRODER seem to have been studied in an exhaustive manner in Portugal, whether under laboratory or field conditions. Prats et al. (2012, 2013, 2014) tested two of these measures by field trials, i.e. hydro-mulching and forest residue mulching. The authors found both measures to be highly effective in terms of reducing overland flow and especially erosion. It remains a challenge, however, to assess the effectiveness of these and other measures in a broader context, not only beyond overland flow and sediment losses but also beyond the spatio-temporal scale that are typical for such field trials (plots and the first two years after fire). This challenge will be addressed in the Portuguese case study of the RECARE project. Nonetheless, the present study wants to be a first attempt at an ecosystem services-based assessment of mulching as a post

  14. Dynamics of Sudanian savanna-woodland ecosystem in response to disturbances

    OpenAIRE

    Savadogo, Patrice

    2007-01-01

    Grazing, fire and selective tree cutting are major disturbances shaping species diversity and productivity in savanna-woodland ecosystems. Their effects, however, are highly variable and poorly understood. Structural and functional responses of the Sudanian savanna-woodland ecosystem to such disturbances were investigated, with particular emphasis on the herbaceous vegetation. Fuel and fire behaviour were characterized in relation to grazing, dominant grass type and wind direction. The result...

  15. Pesticide usage pattern in tea ecosystem, their retrospects and alternative measures.

    Science.gov (United States)

    Gurusubramanian, G; Rahman, A; Sarmah, M; Ray, Somnath; Bora, S

    2008-11-01

    Tea is a perennial plantation crop grown under monoculture providing favorable conditions for a variety of pests. The concept of pest control has undergone a considerable change over the past few decades. In recent years there has been a greater dependence on the use of pesticides (7.35-16.75 kgha(-1)) with little importance laid on other safe control methods for the management of tea pests. Due to this practice, the tea pests showed a higher tolerance/ resistance status due to formation of greater amount of esterases, glutathione S-transferase and acetylcholinesterase. Thus, over reliance on pesticides end up with pesticide residue in made tea (DDT - 10.4-47.1%; endosulfan - 41.1-98.0%; dicofol- 0.0-82.4%; ethion - 0.0-36.2%; cypermethrin - 6.0- 45.1%). The growing concern about the pesticide residue in made tea, its toxicity hazards to consumers, the spiraling cost of pesticides and their application have necessitated a suitable planning which will ensure a safe, economic as well as effective pest management in tea. At present it is a global concern to minimize chemical residue in tea and European union and German law imposed stringent measures for the application of chemicals in tea and fixed MRL values at market at global level, central insecticide board and prevention of food adulteration regulation committee have reviewed the MRL position for tea and has recommended 10 insecticides, 5 acaricides, 9 herbicides and 5 fungicides for use in tea and issued the tea distribution and export control order 2005 which will help the country to limit the presence of undesirable substances in tea. This review attempts to provide the readers with a comprehensive account of pesticide use in North East in tea, surveillance report of the European community regarding the residue level in Assam and Darjeeling tea, recent amendments by international and national regulatory bodies, revised MRL values of pesticides in tea, an update about the current strategies for the management

  16. Reconciling In Situ Foliar Nitrogen and Vegetation Structure Measurements with Airborne Imagery Across Ecosystems

    Science.gov (United States)

    Flagg, C.

    2015-12-01

    Over the next 30 years the National Ecological Observatory Network (NEON) will monitor environmental and ecological change throughout North America. NEON will provide a suite of standardized data from several ecological topics of interest, including net primary productivity and nutrient cycling, from 60+ sites across 20 eco-climatic domains when fully operational in 2017. The breadth of sampling includes ground-based measurements of foliar nitrogen and vegetation structure, ground-based spectroscopy, airborne LIDAR, and airborne hyperspectral surveys occurring within narrow overlapping time intervals once every five years. While many advancements have been made in linking and scaling in situ data with airborne imagery, establishing these relationships across dozens of highly variable sites poses significant challenges to understanding continental-wide processes. Here we study the relationship between foliar nitrogen content and airborne hyperspectral imagery at different study sites. NEON collected foliar samples from three sites in 2014 as part of a prototype study: Ordway Swisher Biological Station (pine-oak savannah, with active fire management), Jones Ecological Research Center (pine-oak savannah), and San Joaquin Experimental Range (grass-pine oak woodland). Leaf samples and canopy heights of dominant and co-dominant species were collected from trees located within 40 x 40 meter sampling plots within two weeks of aerial LIDAR and hyperspectral surveys. Foliar canopy samples were analyzed for leaf mass per area (LMA), stable isotopes of C and N, C/N content. We also examine agreement and uncertainty between ground based canopy height and airborne LIDAR derived digital surface models (DSM) for each site. Site-scale maps of canopy nitrogen and canopy height will also be presented.

  17. Emergy and ecosystem complexity

    Science.gov (United States)

    Ulgiati, Sergio; Brown, Mark T.

    2009-01-01

    The question "What drives complexity?" is addressed in this paper. To answer this question, we explore the way energy and material resources of different quality flow through ecosystems and support, directly and indirectly, ecosystems growth and development. Processes of resource transformation throughout the ecosystem build order, cycle materials, generate and sustain information. Energy drives all these processes and energetic principles explain much of what is observed, including energy degradation according to the laws of thermodynamics. Emergy, a quantitative measure of the global environmental work supporting ecosystem dynamics, is used here in order to provide a deeper understanding of complexity growth and decline in ecosystems. Ecosystem complexity is discussed in this paper in relation to changes in structure, organization and functional capacity, as explained by changes in emergy, empower, and transformity.

  18. The pulsed response of soil respiration to precipitation in an African savanna ecosystem: a coupled measurement and modeling approach

    Science.gov (United States)

    Fan, Z.; Neff, J. C.; Hanan, N. P.

    2014-12-01

    Savannas cover 60% of the African continent and play an essential role in the global carbon (C) cycle. To better characterize the physical controls over soil respiration in these settings, half-hourly observations of volumetric soil-water content, temperature, and the concentration of carbon dioxide (CO2) at different soil depths were continually measured from 2005 to 2007 under trees ("sub-canopy") and between trees ("inter-canopy") in a savanna vegetation near Skukuza, Kruger National Park, South Africa. The measured soil climate and CO2 concentration data were assimilated into a process-based model that estimates the CO2 production and flux with coupled dynamics of dissolved organic C (DOC) and microbial biomass C. Our results show that temporal and spatial variations in CO2 flux were strongly influenced by precipitation and vegetation cover, with two times greater CO2 flux in the sub-canopy plots (~2421 g CO2 m-2 yr-1) than in the inter-canopy plots (~1290 g CO2 m-2 yr-1). Precipitation influenced soil respiration by changing soil temperature and moisture; however, our modeling analysis suggests that the pulsed response of soil respiration to precipitation [known as "Birch effect (BE)"] is a key control on soil fluxes at this site. At this site, BE contributed to approximately 50% and 65% of heterotrophic respiration or 20% and 39% of soil respiration in the sub-canopy and inter-canopy plots, respectively. These results suggest that pulsed response of respiration to precipitation is an important component of the C cycle of savannas and should be considered in both measurement and modeling studies of carbon exchange in similar ecosystems.

  19. Ecosystem Jenga!

    Science.gov (United States)

    Umphlett, Natalie; Brosius, Tierney; Laungani, Ramesh; Rousseau, Joe; Leslie-Pelecky, Diandra L.

    2009-01-01

    To give students a tangible model of an ecosystem and have them experience what could happen if a component of that ecosystem were removed; the authors developed a hands-on, inquiry-based activity that visually demonstrates the concept of a delicately balanced ecosystem through a modification of the popular game Jenga. This activity can be…

  20. Natural ecosystems

    Science.gov (United States)

    Fleishman, Erica; Belnap, Jayne; Cobb, Neil; Enquist, Carolyn A.F.; Ford, Karl; MacDonald, Glen; Pellant, Mike; Schoennagel, Tania; Schmit, Lara M.; Schwartz, Mark; van Drunick, Suzanne; Westerling, Anthony LeRoy; Keyser, Alisa; Lucas, Ryan

    2013-01-01

    Natural Ecosystems analyzes the association of observed changes in climate with changes in the geographic distributions and phenology (the timing of blossoms or migrations of birds) for Southwestern ecosystems and their species, portraying ecosystem disturbances—such as wildfires and outbreaks of forest pathogens—and carbon storage and release, in relation to climate change.

  1. Ecosystem Jenga!

    Science.gov (United States)

    Umphlett, Natalie; Brosius, Tierney; Laungani, Ramesh; Rousseau, Joe; Leslie-Pelecky, Diandra L.

    2009-01-01

    To give students a tangible model of an ecosystem and have them experience what could happen if a component of that ecosystem were removed; the authors developed a hands-on, inquiry-based activity that visually demonstrates the concept of a delicately balanced ecosystem through a modification of the popular game Jenga. This activity can be…

  2. Eddy covariance measurements of annual carbon dioxide exchange in two natural ecosystems of the northwestern Italian Alps

    Science.gov (United States)

    Galvagno, Marta; Migliavacca, Mirco; Cremonese, Edoardo; Busetto, Lorenzo; Cogliati, Sergio; Colombo, Roberto; Manca, Giovanni; Meroni, Michele; Morra di Cella, Umberto; Rossini, Micol

    2010-05-01

    In consequence of the relationship between climate change and atmospheric greenhouse gases concentrations, a prime issue of recent researches is the quantification of the carbon balance of terrestrial biomes. In the last decades an increasing number of monitoring sites has recently been implemented worldwide, with the aim to better understand and quantify how inter-annual climate fluctuations affect net carbon exchange and the length of growing season over different vegetation types, land uses and climates. Eddy covariance (EC) technique is a widespread method that provide a direct measure of net carbon dioxide exchange across the biosphere-atmosphere interface by measuring the covariance between fluctuations in vertical wind velocity and CO2 mixing ratio. Two long-term monitoring sites have been equipped in the northwest Italian Alps (Aosta Valley) with the aim of quantify the annual carbon dioxide sequestration by grassland and forest ecosystems in relation to climate change. Grasslands and European larch forests (Larix decidua, Mill.) are the most representative vegetation types of this alpine region. The grassland site, located at an elevation of 2160 m asl, has been equipped in summer 2008 in an abandoned pasture with Nardus stricta as dominant species. European larch stand is located at 2050 m asl, at a distance of ~8 km from the grassland, and measurements has started in winter 2009. Both sites have been equipped with the same eddy flux system mounted at 2.5 m and 20 m above the ground in the grassland and in the larch forest, respectively. Both sites were equipped with a basic EC system: a3D sonic anemometer and an open-path infrared gas analyser (LI-7500, LICOR Inc.). Along EC the main meteorological variables are measured (e.g. air temperature, humidity, precipitation, photosynthetically active radiation, PAR, , soil water content, snow height etc..). In order to link annual sites productivity to the growing seasons length, phenological observations are

  3. Aircraft Regional-Scale Flux Measurements over Complex Landscapes of Mangroves, Desert, and Marine Ecosystems of Magdalena Bay, Mexico

    OpenAIRE

    2013-01-01

    Natural ecosystems are rarely structurally simple or functionally homogeneous. This is true for the complex coastal region of Magdalena Bay, Baja California Sur, Mexico, where the spatial variability in ecosystem fluxes from the Pacific coastal ocean, eutrophic lagoon, mangroves, and desert were studied. The Sky Arrow 650TCN environmental research aircraft proved to be an effective tool in characterizing land–atmosphere fluxes of energy, CO2, and water vapor across a heterogeneous landscape a...

  4. Effects of VOCs on herbaceous plants in an open-top chamber experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cape, J.N.; Leith, I.D.; Binnie, J.; Content, J.; Donkin, M.; Skewes, M.; Price, D.N.; Brown, A.R.; Sharpe, A.D

    2003-07-01

    Birdsfoot trefoil and broad-leaved dock were affected by VOCs. - A selection of herbaceous plants representing the ground flora around a typical chemical installation in the UK was exposed continuously for 7 weeks to a mixture of six VOCs (acetone, acetonitrile, dichloromethane, ethanol, methyl t-butyl ether and toluene) in open-top chambers. Exposure concentrations were based on predictions of atmospheric dispersion from a single source, at a distance of approximately 2 km. The effects of continuous exposure, representing a worst-case, were measured in terms of uncontrolled water loss from leaves, leaf wettability, chlorophyll content and fluorescence, dry matter production and detailed observations of changes in plant growth and phenology. There were significant effects of VOC exposure on seed production, leaf water content and photosynthetic efficiency in some plant species. Such effects may be detectable in vegetation close to major industrial point sources of VOCs, or as a result of an accidental release of material during manufacture or transport. Some of the species tested e.g. birdsfoot trefoil (Lotus corniculatus L.) seem to be promising as potential bioindicators for VOCs, but there may be other even more sensitive species waiting to be discovered. However, the most obvious and conveniently measured response to VOC exposure in the birdsfoot trefoil (premature senescence i.e. advanced timing of seed pod production) could easily be confused in the field with climatic influences. It is also uncertain at this stage whether any of the effects observed would lead to longer term ecological changes in natural plant communities, through biased competition between sensitive and more tolerant species.

  5. The Ecosystems SAR (EcoSAR) an Airborne P-band Polarimetric InSAR for the Measurement of Vegetation Structure, Biomass and Permafrost

    Science.gov (United States)

    Rincon, Rafael F.; Fatoyinbo, Temilola; Ranson, K. Jon; Osmanoglu, Batuhan; Sun, Guoqing; Deshpande, Manohar D.; Perrine, Martin L.; Du Toit, Cornelis F.; Bonds, Quenton; Beck, Jaclyn; hide

    2014-01-01

    EcoSAR is a new synthetic aperture radar (SAR) instrument being developed at the NASA/ Goddard Space Flight Center (GSFC) for the polarimetric and interferometric measurements of ecosystem structure and biomass. The instrument uses a phased-array beamforming architecture and supports full polarimetric measurements and single pass interferometry. This Instrument development is part of NASA's Earth Science Technology Office Instrument Incubator Program (ESTO IIP).

  6. Changes in Herbaceous Species Composition in the Absence of Disturbance in a Cenchrus biflorus Roxb. Invaded Area in Central Kalahari Game Reserve, Botswana

    Directory of Open Access Journals (Sweden)

    Shimane W. Makhabu

    2012-01-01

    Full Text Available A-nine year study was carried out to investigate changes in herbaceous species composition in an area invaded by Cenchrus biflorus Roxb, an exotic invader grass species. The study ensued termination of livestock and human activities in the area when residents of the area were relocated to another area. Vegetation characteristics from the disturbed sites (previous occupied areas and undisturbed sites (previously unoccupied areas were determined. The results show that C. biflorus has high tolerance to disturbance. It comprised the larger proportion of grasses in disturbed sites at the inception of the study. However, it decreased in abundance with time in disturbed areas and was absent in the undisturbed areas, suggesting that its ability to invade undisturbed sites is limited. Perennial species successfully reestablished on the third year after termination of disturbance. The study reveals that C. biflorus invasion in the Kalahari ecosystem can be controlled by termination of disturbances.

  7. Evaluation of N2—Fixing Capacites of Herbaceous and Shrub Legumes Under Field Condition

    Institute of Scientific and Technical Information of China (English)

    XJINGGUANGXI; SHISHULIAN; 等

    1998-01-01

    Natural 15N abundance method was used in this study to investigate the N2-fiing capacities of several herbaceous and shrub legumes by a field experiment,For herbaceous legumes,the results were in consistent with those obtained by a pot experiment .Crotalaria mucronata Desv.had a higher,N2-fixing capacity than Vigna sinensis(L.)Savi.For shurub legumes,N2-fixing Capacity under field condition was slightly different from that in pot experiment.These results demonstrated that the natural 15N abundance method was applicable to evaluating N2-fixing capacities of herbaceous and shrub legumes,and that pot experiment was suitable for evaluating the N2-fixing capacities of not only herbaceous legumes but also shrub legumes. Leguminous N2-fixing plants differed in response to phosphorus fertilization,Phosphorus fertilizer appication greatly increased the percentage of nitrogen derived from air (% N dfa)and total amount of N2 fixed by Lespedez formosa(Vog.)Koehne (Jiangxi),Phosphorus fertilizer showed no signifcant effect on the N2-fixing percentage of Cajanus cajan(L.)Millsp.but increased its total biomass,thus increasing the total amount of N2 fixed.

  8. Integrating remote sensing and spatial statistics to model herbaceous biomass distribution in a tropical savanna

    NARCIS (Netherlands)

    Mutanga, O.; Rugege, D.

    2006-01-01

    Modelling herbaceous biomass is critical for an improved understanding of wildlife feeding patterns and distribution as well as for the development of early warning systems for fire management. Most savannas in South Africa are characterized by complex stand structure and abundant vegetation species

  9. Water and nutrients alter herbaceous competitive effects on tree seedlings in a semi-arid savanna

    NARCIS (Netherlands)

    Waal, van der C.; Kroon, de H.; Boer, de W.F.; Heitkonig, I.M.A.; Skidmore, A.K.; Knegt, de H.J.; Langevelde, van F.; Wieren, van S.E.; Grant, R.C.; Page, B.R.; Slotow, R.; Kohi, E.; Mwakiwa, E.; Prins, H.H.T.

    2009-01-01

    1. Globally, both climatic patterns and nitrogen deposition rates show directional changes over time. It is uncertain how woody seedlings, which coexist with herbaceous plants in savannas, respond to concurrent changes in water and nutrient availability. 2. We investigated competition effects

  10. Coppice management effects on experimentally established populations of three herbaceous layer woodland species

    NARCIS (Netherlands)

    H van Calster; P. Endels; K. Antonio; K. Verheyen; M. Hermy

    2008-01-01

    Traditional coppice management creates a temporal release of resources. We determined how this affected three herbaceous species (Cardamine pratensis, Primula elatior and Geum urbanum) and if it was suitable for their conservation within woodland given their differing phenologies and habitat affinit

  11. [Genetic diversity of rhizobia isolated from shrubby and herbaceous legumes in Shenmu arid area, Shaanxi, China].

    Science.gov (United States)

    Nie, Gang; Chen, Wei-Min; Wei, Ge-Hong

    2014-06-01

    Legume, with a strong resistance to the adverse environmental conditions, is one of pioneer plants in the desert region and plays an important role in the protection of the ecological environment. In this study, the symbiosis of rhizobia associating with shrubby and herbaceous legumes in Shenmu area, Shaanxi, China was characterized by the 16S rRNA PCR-RFLP and sequence analysis of involved genes. A total of 55 strains were isolated and purified, including 30 strains from the shrubby legume Amorpha fruticosa and Caragana microphylla, and 25 strains from herbaceous plants Astragalus adsurgens, Medicago sativa and Astragalus melilotoides. Results showed that there were 11 16S rRNA genotypes. The strains isolated from herbaceous legumes belonged to five genus including Mesorhizobium, Ensifer, Rhizobium, Phyllobacterium and Agrobacterium, which were very close related to M. huakuii, M. mediterraneum, M. robiniae, E. fredii, E. meliloti, R. indigoferae, R. radiobacter, P. ifriqiyense and Ag. tumefaciens through the phylogenetic analysis. The strains isolated from shrubby legumes belonged to Mesorhizobium, and they were very close related to M. huakuii and M. mediterraneum which were shared simultaneously by shrubby and herbaceous legumes. All of these indicated the choice of rhizobia by the two types of legumes in the arid area was different, and it might depend on the species of host plant and environmental factors.

  12. Herbaceous species diversity in relation to fire severity in Zagros oak forests, Iran

    Institute of Scientific and Technical Information of China (English)

    Morteza Pourreza; Seyed Mohsen Hosseini; Ali Akbar Safari Sinegani; Mohammad Matinizadeh; Seyed Jalil Alavai

    2014-01-01

    Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For this purpose neighboring burned and unburned areas were selected with the same plant species and ecological conditions. The data were collected from areas subjected to different fire severities. Overall 6 treatments were considered with respect to fire severity and the mi-crosites of inside and outside of oak sprout clumps including: unburned inside and outside of sprout clumps (Ni and No), inside of sprout clumps that burned with high fire severity (H), inside of sprout clumps that burned with moderate fire severity (M), outside of sprout clumps that burned with low fire severity (OH and OM). Different herbaceous com-position was observed in the unburned inside and outside of oak sprout clumps. The species diversity and richness were increased in treatments burned with low and moderate fire severity. However, in treatment burned with high fire severity (H), herbaceous cover was reduced, even-ness was increased, and richness and diversity were not significantly changed. We concluded that besides the microsites conditions in forest, fire severity is an inseparable part of the ecological effect of fire on her-baceous composition.

  13. Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

    Science.gov (United States)

    Production of advanced biofuels from woody and herbaceous feedstocks is moving into commercialization. Biomass needs to be pretreated to overcome the physicochemical properties of biomass that hinder enzyme accessibility, impeding the conversion of the plant cell walls to fermentable sugars. Pretrea...

  14. Interactions between Canopy Structure and Herbaceous Biomass along Environmental Gradients in Moist Forest and Dry Miombo Woodland of Tanzania.

    Directory of Open Access Journals (Sweden)

    Deo D Shirima

    Full Text Available We have limited understanding of how tropical canopy foliage varies along environmental gradients, and how this may in turn affect forest processes and functions. Here, we analyse the relationships between canopy leaf area index (LAI and above ground herbaceous biomass (AGBH along environmental gradients in a moist forest and miombo woodland in Tanzania. We recorded canopy structure and herbaceous biomass in 100 permanent vegetation plots (20 m × 40 m, stratified by elevation. We quantified tree species richness, evenness, Shannon diversity and predominant height as measures of structural variability, and disturbance (tree stumps, soil nutrients and elevation as indicators of environmental variability. Moist forest and miombo woodland differed substantially with respect to nearly all variables tested. Both structural and environmental variables were found to affect LAI and AGBH, the latter being additionally dependent on LAI in moist forest but not in miombo, where other factors are limiting. Combining structural and environmental predictors yielded the most powerful models. In moist forest, they explained 76% and 25% of deviance in LAI and AGBH, respectively. In miombo woodland, they explained 82% and 45% of deviance in LAI and AGBH. In moist forest, LAI increased non-linearly with predominant height and linearly with tree richness, and decreased with soil nitrogen except under high disturbance. Miombo woodland LAI increased linearly with stem density, soil phosphorous and nitrogen, and decreased linearly with tree species evenness. AGBH in moist forest decreased with LAI at lower elevations whilst increasing slightly at higher elevations. AGBH in miombo woodland increased linearly with soil nitrogen and soil pH. Overall, moist forest plots had denser canopies and lower AGBH compared with miombo plots. Further field studies are encouraged, to disentangle the direct influence of LAI on AGBH from complex interrelationships between stand

  15. Tunable Diode Laser Measurements of Leaf-scale Carbon Isotope Discrimination and Ecosystem Respired Carbon and Oxygen Isotope Ratios in a Semi-arid Woodland

    Science.gov (United States)

    McDowell, N.; Chris, B.; Hanson, D.; Kern, S.; Meyer, C.; Pockman, W.; Powers, H.

    2005-12-01

    We present results and speculative interpretation of leaf-level carbon isotope discrimination and ecosystem respired carbon and oxygen isotope ratios from a semi-arid, C3/C4 woodland located in northern New Mexico, USA. Overstory leaf area index (LAI) is dominated by live juniper (Juniperus monosperma) trees with an LAI value of approximately 1.0 m2 per m2 ground area, and has a seasonally dynamic understory of mixed C3 forbs and C4 grasses and cacti, with a maximum LAI of 0.30 m2 per m2 ground area. Ecosystem respired carbon isotope ratios showed values characteristic of C3 dominated photosynthesis (Keeling plot intercepts of -35 to -22 per mil). Seasonal variation was typical of that found in wetter, C3 dominated forests, as was the dependence on climate (e.g. relationships with vapor pressure deficit, soil water content, and canopy conductance). Leaf-level carbon isotope discrimination of the junipers, measured by coupling a Li-Cor 6400 photosynthesis system to the TDL, provided discrimination-Ci and discrimination-vpd relationships consistent with measured ecosystem respired carbon isotope ratios. The oxygen isotope ratio of ecosystem respiration was dependent on rain water isotope composition, but was correlated with soil water content during rain-free periods. The cumulative effect of vapor pressure deficit after a rain event was tightly correlated with the oxygen isotope ratio of ecosystem respiration, suggesting the primary drivers are evaporative enrichment of soil water and perhaps nocturnal leaf enrichment. Instrument precision for carbon and oxygen isotope ratios of carbon dioxide is 0.06 to 0.18 per mil; however, overall precision is somewhat lower due to pressure and sampling effects.

  16. Progress and challenges in the development of ecosystem accounting as a tool to analyse ecosystem capital

    NARCIS (Netherlands)

    Hein, Lars; Obst, Carl; Edens, Bram; Remme, R.P.

    2015-01-01

    Ecosystem accounting has been developed as a systematic approach to incorporate measures of ecosystem services and ecosystem assets into an accounting structure. Ecosystem accounting involves spatially explicit modelling of ecosystem services and assets, in both physical and monetary terms. A

  17. Fate of polychlorinated biphenyls in a contaminated lake ecosystem: Combining equilibrium passive sampling of sediment and water with total concentration measurements of biota

    DEFF Research Database (Denmark)

    Mäenpää, Kimmo; Leppänen, Matti T.; Figueiredo, Kaisa;

    2015-01-01

    of hydrophobic organic chemicals in biota lipids. The authors' aim was to assess the equilibrium status of polychlorinated biphenyls (PCBs) in a contaminated lake ecosystem and along its discharge course using equilibrium sampling devices for measurements in sediment and water and by also analyzing biota...... in model lipids. Overall, the studied ecosystem appeared to be in disequilibrium for the studied phases: sediment, water, and biota. Chemical activities of PCBs were higher in sediment than in water, which implies that the sediment functioned as a partitioning source of PCBs and that net diffusion occurred...... from the sediment to the water column. Measured lipid-normalized PCB concentrations in biota were generally below equilibrium lipid concentrations relative to the sediment (CLip ⇌Sed ) or water (CLip ⇌W ), indicating that PCB levels in the organisms were below the maximum partitioning levels...

  18. Dynamics of ecosystem services provided by subtropical forests in Southeast China during succession as measured by donor and receiver value

    Science.gov (United States)

    The trends in the provision of ecosystem services during restoration and succession of subtropical forests and plantations were quantified, in terms of both receiver and donor values, based on a case study of a 3-step secondary succession series that included a 400-year-old subtr...

  19. Prediction of harmful water quality parameters combining weather, air quality and ecosystem models with in situ measurement

    Science.gov (United States)

    The ability to predict water quality in lakes is important since lakes are sources of water for agriculture, drinking, and recreational uses. Lakes are also home to a dynamic ecosystem of lacustrine wetlands and deep waters. They are sensitive to pH changes and are dependent on d...

  20. The Development and Validation of an Alternative Assessment to Measure Changes in Understanding of the Longleaf Pine Ecosystem

    Science.gov (United States)

    Dentzau, Michael W.; Martínez, Alejandro José Gallard

    2016-01-01

    A drawing assessment to gauge changes in fourth grade students' understanding of the essential components of the longleaf pine ecosystem was developed to support an out-of-school environmental education program. Pre- and post-attendance drawings were scored with a rubric that was determined to have content validity and reliability among users. In…

  1. RESOLUTION AND ERROR IN MEASURING LAND-COVER CHANGE: EFFECTS ON ESTIMATING NET CARBON RELEASE FROM MEXICAN TERRESTRIAL ECOSYSTEMS

    Science.gov (United States)

    Reliable estimates of carbon exchange between terrestrial ecosystems and the atmosphere due to land-use change have become increasingly important. One source of land-use changes estimates comes from comparing multi-date remote sensing imagery, though the effect of land-cover clas...

  2. Mean wind patterns and snow depths in an alpine-subalpine ecosystem as measured by damage to coniferous trees

    Science.gov (United States)

    G. L. Wooldridge; R. C. Musselman; R. A. Sommerfeld; D. G. Fox; B. H. Connell

    1996-01-01

    1. Deformations of Engelmann spruce and subalpine fir trees were surveyed for the purpose of determining climatic wind speeds and directions and snow depths in the Glacier Lakes Ecosystem Experiments Site (GLEES) in the Snowy Range of southeastern Wyoming, USA. Tree deformations were recorded at 50- and 100-m grid intervals over areas of c. 30 ha and 300 ha,...

  3. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon Flux Measurements of Montanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

    Directory of Open Access Journals (Sweden)

    Alexander Ač

    2012-01-01

    Full Text Available We explored ability of reflectance vegetation indexes (VIs related to chlorophyll fluorescence emission (686/630, 740/800 and de-epoxidation state of xanthophyll cycle pigments (PRI, calculated as (531−570/(531−570 to track changes in the CO2 assimilation rate and Light Use Efficiency (LUE in montane grassland and Norway spruce forest ecosystems, both at leaf and also canopy level. VIs were measured at two research plots using a ground-based high spatial/spectral resolution imaging spectroscopy technique. No significant relationship between VIs and leaf light-saturated CO2 assimilation (MAX was detected in instantaneous measurements of grassland under steady-state irradiance conditions. Once the temporal dimension and daily irradiance variation were included into the experimental setup, statistically significant changes in VIs related to tested physiological parameters were revealed. ΔPRI and Δ(686/630 of grassland plant leaves under dark-to-full sunlight transition in the scale of minutes were significantly related to MAX (2=0.51. In the daily course, the variation of VIs measured in one-hour intervals correlated well with the variation of Gross Primary Production (GPP, Net Ecosystem Exchange (NEE, and LUE estimated via the eddy-covariance flux tower. Statistical results were weaker in the case of the grassland ecosystem, with the strongest statistical relation of the index 686/630 with NEE and GPP.

  4. Ecosystem process interactions between central Chilean habitats

    Directory of Open Access Journals (Sweden)

    Meredith Root-Bernstein

    2015-01-01

    Full Text Available Understanding ecosystem processes is vital for developing dynamic adaptive management of human-dominated landscapes. We focus on conservation and management of the central Chilean silvopastoral savanna habitat called “espinal”, which often occurs near matorral, a shrub habitat. Although matorral, espinal and native sclerophyllous forest are linked successionally, they are not jointly managed and conserved. Management goals in “espinal” include increasing woody cover, particularly of the dominant tree Acacia caven, improving herbaceous forage quality, and increasing soil fertility. We asked whether adjacent matorral areas contribute to espinal ecosystem processes related to the three main espinal management goals. We examined input and outcome ecosystem processes related to these goals in matorral and espinal with and without shrub understory. We found that matorral had the largest sets of inputs to ecosystem processes, and espinal with shrub understory had the largest sets of outcomes. Moreover, we found that these outcomes were broadly in the directions preferred by management goals. This supports our prediction that matorral acts as an ecosystem process bank for espinal. We recommend that management plans for landscape resilience consider espinal and matorral as a single landscape cover class that should be maintained as a dynamic mosaic. Joint management of espinal and matorral could create new management and policy opportunities.

  5. Assessments of carbon and water cycling in multiple agricultural ecosystems in the Inland Pacific Northwest using eddy covariance flux measurements and integrated basin-crop model simulation

    Science.gov (United States)

    Chi, J.; Maureira, F.; Waldo, S.; O'Keeffe, P.; Pressley, S. N.; Stockle, C. O.; Lamb, B. K.

    2014-12-01

    Local meteorology, crop management practices and site characteristics have important impacts on carbon and water cycling in agricultural ecosystems. This study focuses on carbon and water fluxes measured using eddy covariance (EC) methods and crop simulation models in the Inland Pacific Northwest (IPNW), in association with the Regional Approaches to Climate Change (REACCH) program. The agricultural ecosystem is currently challenged by higher pressure on water resources as a consequence of population growth and increasing exposure to impacts associated with different types of crop managements. In addition, future climate projections for this region show a likely increase in temperature and significant reductions in precipitation that will affect carbon and water dynamics. This new scenario requires an understanding of crop management by assessing efficient ways to face the impacts of climate change at the micrometeorological level, especially in regards to carbon and water flow. We focus on three different crop management sites. One site (LIND) under crop-fallow is situated in a low-rainfall area. The other two sites, one no-till site (CAF-NT) and one conventional tillage site (CAF-CT), are located in an area of high-rainfall with continuous cropping. In this study, we used CropSyst micro-basin model to simulate the responses in carbon and water budgets at each site. Based on the EC processed results for net ecosystem exchange (NEE) of CO2, the CAF-NT site was a carbon sink during 2013 when spring garbanzo was planted; while the paired CAF-CT site, under similar crop rotation and meteorological conditions, was a carbon source during the same period. The LIND site was also a carbon sink where winter wheat was growing during 2013. Model results for CAF-NT showed good agreement with the EC carbon and water flux measurements during 2013. Through comparisons between measurements and modeling results, both short and long term processes that influence carbon and water

  6. Effect of woody and herbaceous plants on chemical weathering of basalt material

    Science.gov (United States)

    Mark, N.; Dontsova, K.; Barron-Gafford, G. A.

    2011-12-01

    Worldwide, semi-arid landscapes are transitioning from shallow-rooted grasslands to mixed vegetation savannas composed of deeper-rooted shrubs. These contrasting growth forms differentially drive below-ground processes because they occupy different soil horizons, are differentially stressed by periods of drought, and unequally stimulate soil weathering. Our study aims to determine the effect of woody and herbaceous plants on weathering of granular basalt serving as a model for soil. We established pots with velvet mesquite (Prosopis veluntina), sideoats grama (Bouteloua curtipendula), and bare-soil pots within two temperature treatments in University of Arizona Biosphere 2. The Desert biome served as the ambient temperature treatment, while the Savanna biome was maintained 4°C warmer to simulate projected air temperatures if climate change continues unabated. Rhizon water samplers were installed at a depth of one inch from the soil surface to monitor root zone exudates (total dissolved carbon and nitrogen), dissolved inorganic carbon, and lithogenic elements resulting from basalt weathering. Soil leachates were collected through the course of the experiment. The anion content of the leachates was determined using the ICS-5000 Reagent-Free ion chromatography system. Dissolved carbon and nitrogen were analyzed by combustion using the Shimadzu TOC-VCSH with TN module. Metals and metalloids were measured using inductively coupled plasma mass spectrometry. Irrigation of the pots was varied in time to simulate periods of drought and determine the effect of stress on root exudation. Leachates from all treatments displayed higher pH and electrical conductivity than water used for irrigation indicating weathering. On average, leachates from the potted grasses displayed higher pH and electrical conductivity than mesquites. This agreed with higher concentrations of organic carbon, a measure of root exudation, and inorganic carbon, measure of soil respiration. Both organic

  7. What Are Ecosystem Services?

    OpenAIRE

    Boyd, James; Banzhaf, H. Spencer

    2006-01-01

    This paper advocates consistently defined units of account to measure the contributions of nature to human welfare. We argue that such units have to date not been defined by environmental accounting advocates and that the term “ecosystem services” is too ad hoc to be of practical use in welfare accounting. We propose a definition, rooted in economic principles, of ecosystem service units. A goal of these units is comparability with the definition of conventional goods and services found in GD...

  8. Arbuscular mycorrhizal symbiosis of herbaceous invasive neophytes in the Czech Republic

    OpenAIRE

    Štajerová, Kateřina

    2009-01-01

    I have studied arbuscular mycorrhizal symbiosis of 44 herbaceous invasive neophytes occuring in the Czech Republic. My results show that about 70% of the examined species are capable to form symbiotic association with arbuscular mycorrhizal fungi (AMF) in the field. To my knowledge, mycorrhizal status of 23 invasive species is reported here for the first time. I predicted, based on the hypothesis of Urcelay & Díaz (2003), that the intensity of AMF in the roots of invasive species will be corr...

  9. Forest fragmentation effects on patch occupancy and population viability of herbaceous plant species

    OpenAIRE

    Honnay, Olivier; Jacquemyn, Hans; Bossuyt, B; Hermy, Martin

    2005-01-01

    Habitat fragmentation is one of the major threats to species diversity. In this review, we discuss how the genetic and demographic structure of fragmented populations of herbaceous forest plant species is affected by increased genetic drift and inbreeding, reduced mate availability, altered interactions with pollinators, and changed environmental conditions through edge effects. Reported changes in population genetic and demographic structure of fragmented plant populations have, however, not...

  10. [Biological activity of fungi from the phyllosphere of weeds and wild herbaceous plants].

    Science.gov (United States)

    Berestitskiĭ, A O; Gasich, E L; Poluéktova, E V; Nikolaeva, E V; Sokornova, S V; Khlopunova, L B

    2014-01-01

    Antimicrobial, phytotoxic, and insecticidal activity of 30 fungal isolates obtained from leaves of weeds and wild herbaceous plants was assessed. Antibacterial, antifungal, phytotoxic, and insecticidal activity was found in over 50, 40, 47, and 40% of the isolates, respectively. These findings may be important for toxicological assessment of potential mycoherbicides, as well as provide a basis for investigation of the patterns of development of phyllosphere communities affected by fungal metabolites.

  11. Environmental controls on seasonal ecosystem evapotranspiration/potential evapotranspiration ratio as determined by the global eddy flux measurements

    Science.gov (United States)

    Liu, Chunwei; Sun, Ge; McNulty, Steven G.; Noormets, Asko; Fang, Yuan

    2017-01-01

    The evapotranspiration / potential evapotranspiration (AET / PET) ratio is traditionally termed as the crop coefficient (Kc) and has been generally used as ecosystem evaporative stress index. In the current hydrology literature, Kc has been widely used as a parameter to estimate crop water demand by water managers but has not been well examined for other types of ecosystems such as forests and other perennial vegetation. Understanding the seasonal dynamics of this variable for all ecosystems is important for projecting the ecohydrological responses to climate change and accurately quantifying water use at watershed to global scales. This study aimed at deriving monthly Kc for multiple vegetation cover types and understanding its environmental controls by analyzing the accumulated global eddy flux (FLUXNET) data. We examined monthly Kc data for seven vegetation covers, including open shrubland (OS), cropland (CRO), grassland (GRA), deciduous broad leaf forest (DBF), evergreen needle leaf forest (ENF), evergreen broad leaf forest (EBF), and mixed forest (MF), across 81 sites. We found that, except for evergreen forests (EBF and ENF), Kc values had large seasonal variation across all land covers. The spatial variability of Kc was well explained by latitude, suggesting site factors are a major control on Kc. Seasonally, Kc increased significantly with precipitation in the summer months, except in EBF. Moreover, leaf area index (LAI) significantly influenced monthly Kc in all land covers, except in EBF. During the peak growing season, forests had the highest Kc values, while croplands (CRO) had the lowest. We developed a series of multivariate linear monthly regression models for Kc by land cover type and season using LAI, site latitude, and monthly precipitation as independent variables. The Kc models are useful for understanding water stress in different ecosystems under climate change and variability as well as for estimating seasonal ET for large areas with mixed

  12. Toward restoring the net carbon sink function of degraded peatlands: Short-term response in CO2 exchange to ecosystem-scale restoration

    Science.gov (United States)

    Waddington, J. M.; Strack, M.; Greenwood, M. J.

    2010-03-01

    Northern peatlands represent a globally important stock of soil carbon and have acted as a net sink of atmospheric CO2 throughout the Holocene. Disturbance for horticultural peat extraction disrupts ecosystem function and converts these ecosystems to large, persistent sources of carbon dioxide (CO2). This study investigates the effect of ecosystem-scale restoration on growing season CO2 exchange in a peatland by comparing a restored site to a neighboring nonrestored section for 1 year prerestoration (1999) and 3 years postrestoration (2000-2002). Prior to restoration, less than 23% of the site was vegetated, and it was a source of 245 g C m-2 to the atmosphere during the growing season (May to early October). Following restoration, the water table remained deep, and soil moisture was significantly higher than the nonrestored section. By the third year postrestoration, vegetation covered 50% of the restored peatland. Moss covered 90% of this vegetated area. Vegetation productivity at the restored site was also enhanced with gross ecosystem photosynthesis under full light conditions significantly higher at the restored site at both moss and herbaceous plots by 2002. While this increase in vegetation productivity provided fresh substrate and resulted in higher CO2 production potential for restored site peat, ecosystem respiration was similar to or lower than that at the nonrestored site for both bare peat and vegetated areas because of the generally wetter site conditions resulting from restoration. By upscaling chamber CO2 exchange measurements to the ecosystem level, on the basis of the relative proportion of each surface cover type, we determined the site was a net sink of ˜20 ± 5 g C m-2 during the growing season only 2 years postrestoration. Combining our results with previous work on CH4 emissions and dissolved organic carbon export, we suggest that this degraded peatland ecosystem will likely return to a net carbon sink in 6 to 10 years postrestoration.

  13. Participation of the indigenous vs. alien herbaceous species to the constitution of vegetal layer on the Bozanta Mare tailing ponds

    Directory of Open Access Journals (Sweden)

    Monica MARIAN

    2010-05-01

    Full Text Available This study explored the distribution of different species of native and alien herbaceous species on the tailing pond Bozânta Mare (Maramureş county in NW Romania and the differences in heavy metal uptake in the roots and shoots relative to: 1. herbaceous species; 2. differential metal uptake and variation within single-species; 3. metal content of soil substrate. In 2007-2009 the contribution of native and alien species to the herbaceous layer forming, were studied on the Bozânta Mare tailing pond, resulted after heavy metal extraction process. The heavy metals found at elevated level in the herbaceous species included for environmental interest are: Pb, Cu, Ni, Zn, Co, Cd, Fe, Cr, Mn, Na, K. Also, the aim of this research is to evaluate the impact of the native vs. alien species presence in the colonization process on the tailing pond.

  14. Characterization of Combustion and Emission of Several Kinds of Herbaceous Biomass Pellets in a Circulating Fluidized Bed Combustor

    Science.gov (United States)

    Li, S. Y.; Teng, H. P.; Jiao, W. H.; Shang, L. L.; Lu, Q. G.

    Characterizations of combustion and emission of four kinds of herbaceous biomass pellets were investigated in a 0.15 MWt circulating fluidized bed. Corn stalk, wheat stalk, cotton stalk and king grass, which are typical herbaceous biomass in China, were chosen for this study. Temperature profile, emission in flue gas and agglomeration were studied by changing the combustion temperature between 750°C and 880°C. The combustion efficiencies are in the range from 97.4% to 99.4%, which are relatively high due to the homogeneous temperature profiles and good circulating fluidization of bed material. Suitable combustion temperatures for the different herbaceous biomass are mainly depended on the emission and bed agglomeration. SO2 and HCl concentrations in flue gas are in direct proportion to the sulfur and chlorine contents of the herbaceous biomass. Agglomeration at the cyclone leg and the loop seal is the main reason for defluidization in the CFB combustor.

  15. Effects of herbaceous vegetation on the survival and growth of hardwood tree seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, E.W.

    1979-12-01

    First year survival and growth of several hardwood tree species planted with herbaceous vegetation on recently mined areas where soil, lime, and fertilizers were used at five locations throughout the bituminous coal region of Pennsylvania is discussed. In one study begun in 1978, five tree species (Robinia pseudacaia, Quercus rubra, Liriodendron tulipifera, Populus robusta, and Juglans nigra) were planted in vegetated and non-vegetated plots. Survival was good for all species except Populus robusta, which failed due to poor quality stock. Height growth of Robinia pseudoacacia was good, all other species were poor. In another study in 1978, herbaceous competition was evaluated using three grass-legume mixtures (Lotus corniculatus L. with either Festuca arundinacea L., Eragrostis curvula L.), seeded at two rates, and using two herbicides on an area with a previously established cover. No significant differences occurred between herbaceous covers in survival and first year height growth of the two species (Robinia pseudoacacia and Quercus rubra) used. In a third study begun in 1979, eight tree species (the five already mentioned plus Alnus gluthosa, Acer saccharum, and Fraxinus americana) were planted in non-seeded plots and in plots seeded with two different mixtures (Festuca arundinacea L. with either Lotus corniculatus or Cornilla varia L.). Early survival was good for all species.

  16. Above- and belowground competition from longleaf pine plantations limits performance of reintroduced herbaceous species.

    Energy Technology Data Exchange (ETDEWEB)

    T.B. Harrington; C.M. Dagley; M.B. Edwards.

    2003-10-01

    Although overstory trees limit the abundance and species richness of herbaceous vegetation in longleaf pine (Pinus palustris Mill.) plantations, the responsible mechanisms are poorly understood because of confounding among limiting factors. In fall 1998, research was initiated to determine the separate effects of above- and belowground competition and needlefall from overstory pines on understory plant performance. Three 13- to 15-yr-old plantations near Aiken, SC, were thinned to 0, 25, 50, or 100% of nonthinned basal area (19.5 m2 ha-1). Combinations of trenching (to eliminate root competition) and needlefall were applied to areas within each plot, and containerized seedlings of 14 perennial herbaceous species and longleaf pine were planted within each. Overstory crown closure ranged from 0 to 81%, and soil water and available nitrogen varied consistently with pine stocking, trenching, or their combination. Cover of planted species decreased an average of 16.5 and 14.1% as a result of above- and below-ground competition, respectively. Depending on species, needlefall effects were positive, negative, or negligible. Results indicate that understory restoration will be most successful when herbaceous species are established within canopy openings (0.1-0.2 ha) managed to minimize negative effects from above- and belowground competition and needlefall.

  17. Ecosystem functioning

    National Research Council Canada - National Science Library

    Jax, Kurt

    2010-01-01

    "In the face of decreasing biodiversity and ongoing global changes, maintaining ecosystem functioning is seen both as a means to preserve biological diversity as well as for safeguarding human well...

  18. Environmental impacts on the evapotranspiration of an water limited and heterogeneous Mediterranean ecosystem.

    Science.gov (United States)

    Montaldo, N.; Curreli, M.; Corona, R.; Oren, R.

    2015-12-01

    Mediterranean water limited ecosystems are characterized by an heterogeneous spatial distribution of different plant functional types (PFT), such as grass and trees, competing for water use. Typically, during the dry summers, these ecosystems are characterized by a simple dual PFTs system with strong-resistant woody vegetation and bare soil, since grass died. The coupled use of sap flow measurements and eddy covariance technique is essential to estimate Evapotransiration (ET) in an heterogeneous ecosystem. An eddy covariance - micrometeorological tower has been installed since 2003 and 33 thermo-dissipation probes based on the Granier technique have installed at the Orroli site in Sardinia (Italy). The site landscape is a mixture of Mediterranean patchy vegetation types: wild olives, different shrubs and herbaceous species, which died during the summer. The sensors have been installed at the Orroli site into 15 wild olives clumps with different characteristics in terms of tree size, exposition to wind and solar radiation and soil depth. A network of 30 soil moisture sensors has also been installed for monitoring soil moisture spatial and temporal dynamics and their correlation with trees. Sap flow measurements show the significantly impacts on ET of soil moisture, radiation, vapor pressure deficit (VPD) and interestingly of tree position into the clump, showing double rates for the trees inside the wild olive clumps. The sap flow sensor outputs are analyzed for estimating innovative allometric relationships between sapwood area, diameter, canopy cover area, which are needed for the correct upscale of the local tree measurements to the site plot larger scale. Finally using an innovative scaling procedure, the sap-flow transpiration at field scale have been compared to the eddy covariance ET, showing the approximation of the eddy covariance technique. Finally the impact of environmental factors on ET for different soil depth and tree position is demonstrated.

  19. Partitioning understory evapotranspiration in semi-arid ecosystems in Namibia using the isotopic composition of water vapour

    Science.gov (United States)

    de Blécourt, Marleen; Gaj, Marcel; Holtorf, Kim-Kirsten; Gröngröft, Alexander; Brokate, Ralph; Himmelsbach, Thomas; Eschenbach, Annette

    2016-04-01

    In dry environments with a sparse vegetation cover, understory evapotranspiration is a major component of the ecosystem water balance. Consequently, knowledge on the size of evapotranspiration fluxes and the driving factors is important for our understanding of the hydrological cycle. Understory evapotranspiration is made up of soil evaporation and plant transpiration. Soil evaporation can be measured directly from patches free of vegetation. However, when understory vegetation is present distinguishing between soil evaporation and plant transpiration is challenging. In this study, we aim to partition understory evapotranspiration based on an approach that combines the measurements of water-vapour fluxes using the closed chamber method with measurements of the isotopic composition of water vapour. The measurements were done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management). The study sites were located in three different semi-arid ecosystems in Namibia: thornbush savanna, Baikiaea woodland and shrubland. At each site measurements were done under tree canopies as well as at unshaded areas between the canopies. We measured evaporation from the bare soil and evapotranspiration from patches covered with herbaceous species and shrubs using a transparent chamber connected with an infrared gas analyser (LI-8100A, LICOR Inc.). The stable isotope composition of water vapour inside the chamber and depth profiles of soil water stable isotopes were determined in-situ using a tuneable off-axis integrated cavity output spectroscope (OA-ICOS, Los Gatos Research, DLT 100). Xylem samples were extracted using the cryogenic vacuum extraction method and the isotopic composition of the extracted water was measured subsequently with a cavity-ring-down spectrometer (CRDS L2120-i, Picarro Inc.). We will present the quantified fluxes of understory evapotranspiration measured in the three different ecosystems, show the

  20. Above-ground woody carbon sequestration measured from tree rings is coherent with net ecosystem productivity at five eddy-covariance sites.

    Science.gov (United States)

    Babst, Flurin; Bouriaud, Olivier; Papale, Dario; Gielen, Bert; Janssens, Ivan A; Nikinmaa, Eero; Ibrom, Andreas; Wu, Jian; Bernhofer, Christian; Köstner, Barbara; Grünwald, Thomas; Seufert, Günther; Ciais, Philippe; Frank, David

    2014-03-01

    • Attempts to combine biometric and eddy-covariance (EC) quantifications of carbon allocation to different storage pools in forests have been inconsistent and variably successful in the past. • We assessed above-ground biomass changes at five long-term EC forest stations based on tree-ring width and wood density measurements, together with multiple allometric models. Measurements were validated with site-specific biomass estimates and compared with the sum of monthly CO₂ fluxes between 1997 and 2009. • Biometric measurements and seasonal net ecosystem productivity (NEP) proved largely compatible and suggested that carbon sequestered between January and July is mainly used for volume increase, whereas that taken up between August and September supports a combination of cell wall thickening and storage. The inter-annual variability in above-ground woody carbon uptake was significantly linked with wood production at the sites, ranging between 110 and 370 g C m(-2) yr(-1) , thereby accounting for 10-25% of gross primary productivity (GPP), 15-32% of terrestrial ecosystem respiration (TER) and 25-80% of NEP. • The observed seasonal partitioning of carbon used to support different wood formation processes refines our knowledge on the dynamics and magnitude of carbon allocation in forests across the major European climatic zones. It may thus contribute, for example, to improved vegetation model parameterization and provides an enhanced framework to link tree-ring parameters with EC measurements.

  1. Ecosystem-based management and the wealth of ecosystems.

    Science.gov (United States)

    Yun, Seong Do; Hutniczak, Barbara; Abbott, Joshua K; Fenichel, Eli P

    2017-06-20

    We merge inclusive wealth theory with ecosystem-based management (EBM) to address two challenges in the science of sustainable management of ecosystems. First, we generalize natural capital theory to approximate realized shadow prices for multiple interacting natural capital stocks (species) making up an ecosystem. These prices enable ecosystem components to be better included in wealth-based sustainability measures. We show that ecosystems are best envisioned as portfolios of assets, where the portfolio's performance depends on the performance of the underlying assets influenced by their interactions. Second, changes in ecosystem wealth provide an attractive headline index for EBM, regardless of whether ecosystem wealth is ultimately included in a broader wealth index. We apply our approach to the Baltic Sea ecosystem, focusing on the interacting community of three commercially important fish species: cod, herring, and sprat. Our results incorporate supporting services embodied in the shadow price of a species through its trophic interactions. Prey fish have greater shadow prices than expected based on market value, and predatory fish have lower shadow prices than expected based on market value. These results are because correctly measured shadow prices reflect interdependence and limits to substitution. We project that ecosystem wealth in the Baltic Sea fishery ecosystem generally increases conditional on the EBM-inspired multispecies maximum sustainable yield management beginning in 2017, whereas continuing the current single-species management generally results in declining wealth.

  2. Defining Ecosystem Assets for Natural Capital Accounting.

    Science.gov (United States)

    Hein, Lars; Bagstad, Ken; Edens, Bram; Obst, Carl; de Jong, Rixt; Lesschen, Jan Peter

    2016-01-01

    In natural capital accounting, ecosystems are assets that provide ecosystem services to people. Assets can be measured using both physical and monetary units. In the international System of Environmental-Economic Accounting, ecosystem assets are generally valued on the basis of the net present value of the expected flow of ecosystem services. In this paper we argue that several additional conceptualisations of ecosystem assets are needed to understand ecosystems as assets, in support of ecosystem assessments, ecosystem accounting and ecosystem management. In particular, we define ecosystems' capacity and capability to supply ecosystem services, as well as the potential supply of ecosystem services. Capacity relates to sustainable use levels of multiple ecosystem services, capability involves prioritising the use of one ecosystem service over a basket of services, and potential supply considers the ability of ecosystems to generate services regardless of demand for these services. We ground our definitions in the ecosystem services and accounting literature, and illustrate and compare the concepts of flow, capacity, capability, and potential supply with a range of conceptual and real-world examples drawn from case studies in Europe and North America. Our paper contributes to the development of measurement frameworks for natural capital to support environmental accounting and other assessment frameworks.

  3. Eddy covariance fluxes and vertical concentration gradient measurements of NO and NO2 over a ponderosa pine ecosystem: observational evidence for within canopy removal of NOx

    Science.gov (United States)

    Min, K.-E.; Pusede, S. E.; Browne, E. C.; LaFranchi, B. W.; Wooldridge, P. J.; Cohen, R. C.

    2013-05-01

    Exchange of NOx (NO+NO2) between the atmosphere and biosphere is important for air quality, climate change, and ecosystem nutrient dynamics. There are few direct ecosystem scale measurements of the direction and rate of atmosphere-biosphere exchange of NOx. As a result, a complete description of the processes affecting NOx following emission from soils and/or plants as they transit from within the plant/forest canopy to the free atmosphere remains poorly constrained and debated. Here, we describe measurements of NO and NO2 fluxes and vertical concentration gradients made during the Biosphere Effects on AeRosols and Photochemistry EXperiment 2009. In general, during daytime we observe upward fluxes of NO and NO2 with counter-gradient fluxes of NO. We find that NOx fluxes from the forest canopy are smaller than calculated using observed flux-gradient relationships for conserved tracers and also smaller than measured soil NO emissions. We interpret these differences as evidence for the existence of a "canopy reduction factor". We suggest that at this site it is primarily due to chemistry converting NOx to higher nitrogen oxides within the forest canopy.

  4. Eddy covariance fluxes and vertical concentration gradient measurements of NO and NO2 over a ponderosa pine ecosystem: observational evidence for within-canopy chemical removal of NOx

    Science.gov (United States)

    Min, K.-E.; Pusede, S. E.; Browne, E. C.; LaFranchi, B. W.; Cohen, R. C.

    2014-06-01

    Exchange of NOx (NO+NO2) between the atmosphere and biosphere is important for air quality, climate change, and ecosystem nutrient dynamics. There are few direct ecosystem-scale measurements of the direction and rate of atmosphere-biosphere exchange of NOx. As a result, a complete description of the processes affecting NOx following emission from soils and/or plants as they transit from within the plant/forest canopy to the free atmosphere remains poorly constrained and debated. Here, we describe measurements of NO and NO2 fluxes and vertical concentration gradients made during the Biosphere Effects on AeRosols and Photochemistry EXperiment 2009. In general, during daytime we observe upward fluxes of NO and NO2 with counter-gradient fluxes of NO. We find that NOx fluxes from the forest canopy are smaller than calculated using observed flux-gradient relationships for conserved tracers and also smaller than measured soil NO emissions. We interpret these differences as primarily due to chemistry converting NOx to higher nitrogen oxides within the forest canopy, which might be part of a mechanistic explanation for the "canopy reduction factor" applied to soil NOx emissions in large-scale models.

  5. Effects of uprooting tree on herbaceous species diversity, woody species regeneration status and soft physical characteristics in a temperate mixed forest of Iran

    Institute of Scientific and Technical Information of China (English)

    Y.Kooch; S.M.Hosseini; J.Mohammadi; S.M.Hojjati

    2012-01-01

    We conducted a study to examine the pattern of development of herbaceous plant species,woody species regeneration and soil physical characteristics after tree uprooting in 20-ha areas of Experimental Forest Station of Tarbiat Modares University located in a temperate forest of Mazandaran province in the north of Iran.Soil bulk density,soil texture and moisture from pit and mound (PM) were measured in the laboratory.Results show that the soil bulk density was most in soil deeper layers at mound top,and the soil moisture content was most in soil deeper layers at Pit bottom.Our study supports that the micro-topography of PM (pit and mound) topography will create a mosaic of environmental conditions.This environmental heterogeneity could be responsible for the diversity of herbaceous plant species and regeneration of woody species.It is recommend that the fallen trees with PM structure should remain in the protected area without clearing as the best option for forest restoration.This information can be useful for forest management that attempts to emulate natural processes.

  6. The Ecosystem Approach for the design of compensation and mitigation measures on coastal marine environment: the case study of Civitavecchia harbour

    Science.gov (United States)

    Marcelli, Marco; Scanu, Sergio; Piermattei, Viviana; Bonamano, Simone; Mancini, Emanuele; Madonia, Alice

    2017-04-01

    The coastal marine domain is characterized by physical and ecological conditions that favour and determine a spatial overlap between the different uses of natural resources. In this context, the coastal area of Civitavecchia houses important biodiversity hotspots as well as multiple human activities, being affected by potential conflicts. In particular, the works of expansion scheduled for the Port of Civitavecchia, one of the largest in Europe in terms of cruise and ferry traffic, could impact on two Sites of Community Importance (IT6000005 and IT6000006), for the presence of priority habitats (Posidonia oceanica meadows and reefs of rocky substrates and biogenic concretions) and species (Pinna nobilis and Corallium rubrum) according to Habitat Directive 92/43/EEC. Considering that the Natural Capital analysis is indeed a valid emerging management tool for marine conflicts resolution (Maritime Spatial Planning Directive 2014/89 / EU - MSP), this study aims to propose a methodology to quantify the compensation and mitigation measures, evaluating the ecosystem services of priority habitats and species impacted by harbour expansion activities. To evaluate the ecosystem services the benthic biocoenoses, analyzed in the study area over the past 35 years, were chosen as reference spatial unit. We present the results of the economic evaluation of the benefits produced by Posidonia oceanica meadows (Habitat 1120), and Reef (Habitat 1170). For Posidonia oceanica meadows we computed benefits in relation to carbon sequestration, erosion control, bioremediation, food production, recreational potential and O2 supply, for Reefs using the method proposed by De Groot et al. 2012. The results of the economic assessment of ecosystem services for Habitat 1120 are in agreement with literature data. The results for the services related to the Habitat 1120 are significantly lower because of the influence of the ongoing impacts of human activity. This study allowed to define a specific

  7. Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange

    Science.gov (United States)

    Dubbert, Maren; Piayda, Arndt; Cuntz, Matthias; Correia, Alexandra C.; Costa e Silva, Filipe; Pereira, Joao S.; Werner, Christiane

    2014-01-01

    Semi-arid ecosystems contribute about 40% to global net primary production (GPP) even though water is a major factor limiting carbon uptake. Evapotranspiration (ET) accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is crucial to gain mechanistic understanding of vegetation effects on carbon and water cycling. However, the possible impact of herbaceous vegetation in savanna type ecosystems is often overlooked. Therefore, we aimed at quantifying understory vegetation effects on the water balance and productivity of a Mediterranean oak savanna. ET and net ecosystem CO2 exchange (NEE) were partitioned based on flux and stable oxygen isotope measurements and also rain infiltration was estimated. The understory vegetation contributed importantly to total ecosystem ET and GPP with a maximum of 43 and 51%, respectively. It reached water-use efficiencies (WUE; ratio of carbon gain by water loss) similar to cork-oak trees. The understory vegetation inhibited soil evaporation (E) and, although E was large during wet periods, it did not diminish WUE during water-limited times. The understory strongly increased soil water infiltration, specifically following major rain events. At the same time, the understory itself was vulnerable to drought, which led to an earlier senescence of the understory growing under trees as compared to open areas, due to competition for water. Thus, beneficial understory effects are dominant and contribute to the resilience of this ecosystem. At the same time the vulnerability of the understory to drought suggests that future climate change scenarios for the Mediterranean basin threaten understory development. This in turn will very likely diminish beneficial understory effects like infiltration and ground water recharge and therefore ecosystem resilience to drought. PMID

  8. Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange.

    Science.gov (United States)

    Dubbert, Maren; Piayda, Arndt; Cuntz, Matthias; Correia, Alexandra C; Costa E Silva, Filipe; Pereira, Joao S; Werner, Christiane

    2014-01-01

    Semi-arid ecosystems contribute about 40% to global net primary production (GPP) even though water is a major factor limiting carbon uptake. Evapotranspiration (ET) accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is crucial to gain mechanistic understanding of vegetation effects on carbon and water cycling. However, the possible impact of herbaceous vegetation in savanna type ecosystems is often overlooked. Therefore, we aimed at quantifying understory vegetation effects on the water balance and productivity of a Mediterranean oak savanna. ET and net ecosystem CO2 exchange (NEE) were partitioned based on flux and stable oxygen isotope measurements and also rain infiltration was estimated. The understory vegetation contributed importantly to total ecosystem ET and GPP with a maximum of 43 and 51%, respectively. It reached water-use efficiencies (WUE; ratio of carbon gain by water loss) similar to cork-oak trees. The understory vegetation inhibited soil evaporation (E) and, although E was large during wet periods, it did not diminish WUE during water-limited times. The understory strongly increased soil water infiltration, specifically following major rain events. At the same time, the understory itself was vulnerable to drought, which led to an earlier senescence of the understory growing under trees as compared to open areas, due to competition for water. Thus, beneficial understory effects are dominant and contribute to the resilience of this ecosystem. At the same time the vulnerability of the understory to drought suggests that future climate change scenarios for the Mediterranean basin threaten understory development. This in turn will very likely diminish beneficial understory effects like infiltration and ground water recharge and therefore ecosystem resilience to drought.

  9. Stable oxygen isotope and flux partitioning demonstrates understory of an oak savanna contributes up to half of ecosystem carbon and water exchange

    Directory of Open Access Journals (Sweden)

    Maren eDubbert

    2014-10-01

    Full Text Available Semi-arid ecosystems contribute about 40% to global net primary production (GPP even though water is a major factor limiting carbon uptake. Evapotranspiration (ET accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is crucial to gain mechanistic understanding of vegetation effects on carbon and water cycling. However, the possible impact of herbaceous vegetation in savanna type ecosystems is often overlooked. Therefore, we aimed at quantifying understory vegetation effects on the water balance and productivity of a Mediterranean oak savanna. ET and net ecosystem CO2 exchange (NEE were partitioned based on flux and stable oxygen isotope measurements and also rain infiltration was estimated.The understory vegetation contributed importantly to total ecosystem ET and GPP with a maximum of 43% and 51%, respectively. It reached water-use efficiencies (WUE; ratio of carbon gain by water loss similar to cork-oak trees. The understory vegetation inhibited soil evaporation (E and, although E was large during wet periods, it did not diminish WUE during water-limited times. The understory strongly increased soil water infiltration, specifically following major rain events. At the same time, the understory itself was vulnerable to drought, which led to an earlier senescence of the understory growing under trees as compared to open areas, due to competition for water. Thus, beneficial understory effects are dominant and contribute to the resilience of this ecosystem. At the same time the vulnerability of the understory to drought suggests that future climate change scenarios for the Mediterranean basin threaten understory development. This in turn will very likely diminish beneficial understory effects like infiltration and ground water recharge and therefore ecosystem resilience to

  10. Soil influence on the performance of 26 native herbaceous plants suitable for sustainable Mediterranean landscaping

    Science.gov (United States)

    Bretzel, Francesca; Pezzarossa, Beatrice; Benvenuti, Stefano; Bravi, Alessio; Malorgio, Fernando

    2009-09-01

    Native herbaceous plants have the potential for renaturalizing and recovering derelict soils, such as urban or anthropized soils. Ecological restoration following the establishment of a native wildflower meadow should lead to a reduction in management costs and to the preservation of native plant populations. This study was aimed at determining the ecological characteristics and the cultivation needs of 26 herbaceous species native to Italy and southern Europe in order to identify their landscape potential in low-maintenance conditions. The species were selected on the basis of their adaptation to unproductive soils in semi-natural and rural areas, and on their ornamental value, including their ability to attract insects. Mono-specific plots were set up in three different soils. Seed germination, seedling emergence, flowering dynamics, and plant growth were determined. Dormancy-breaking treatments were effective in improving the germination of most species. The percentage of field establishment and biomass appeared to be affected by the physical and chemical characteristics of the soil. Soil texture slightly affected seedling emergence, whereas soil texture and the C and N levels affected plant growth, the number of flowers and the duration of flowering. Dianthus carthusianorum, Verbascum blattaria, Matricaria chamomilla and Hypochoeris radicata developed a higher biomass per plant in the soils with a low nutrient content, indicating their adaptability to infertile soils. Daucus carota, Papaver rhoeas, Verbascum sinuatum, Coleostephus myconis produced a higher biomass per plant in the most fertile soil, where they appeared to show a higher potential when competing with other species. The ecological characteristics shown by the native plants are extremely important in terms of combining seeds of different species to create and to maintain semi-natural herbaceous communities in low-maintenance landscapes.

  11. Century long assessment of herbaceous plants' physiological responses to climate change in Switzerland

    Science.gov (United States)

    Moreno-Gutierrez, Cristina; Kahmen, Ansgar

    2017-04-01

    The isotopic analysis of archived plant material offers the exceptional opportunity to reconstruct the physiological activity of plants over long time periods and thus, to assess plant responses to environmental changes during the last centuries. In addition, the stable isotope analysis of herbarium samples offers the opportunity to reconstruct the physiological processes of a large range of different plant species and from different environments. Interestingly, only few studies have to date assessed these archives. We will present a novel analysis of leaf nitrogen, oxygen and carbon isotope ratios of more than a thousand herbarium specimens collected since 1800 until present from the unique herbaria hold at the University of Basel. The objective of our study was to assess century-long physiological responses of herbaceous plant species from different plant functional groups and along an altitudinal gradient in Switzerland. The goal of our study was to determine with our investigations the long-term responses of plants to climate change. Such investigations are important as they allow to assess long-term processes of acclimation and adaptation in plants to global enviromental change. In our study we found that herbaceous plants have increased their intrinsic water use efficiency in response to increasing atmospheric CO2 concentration but this increment was higher in plants from higher altitudes, due to the higher efficiency of CO2 assimilation of alpine plants compared to plants from lowlands. There were also differences among functional groups, with grasses and forbs showing the highest increments. In addition, herbaceous plants showed a decreasing trend with time in their N isotopic composition, which may indicate progressive N limitation due to higher biological activity with increasing atmospheric CO2 concentration.

  12. Pervasive interactions between ungulate browsers and disturbance regimes promote temperate forest herbaceous diversity.

    Science.gov (United States)

    Royo, Alejandro A; Collins, Rachel; Adams, Mary Beth; Kirschbaum, Chad; Carson, Walter P

    2010-01-01

    Disruptions to historic disturbance and herbivory regimes have altered plant assemblages in forests worldwide. An emerging consensus suggests that these disruptions often result in impoverished forest biotas. This is particularly true for eastern U.S. deciduous forests where large gaps and understory fires were once relatively common and browsers were far less abundant. Although much research has focused on how disturbance and browsers affect tree diversity, far less attention has been devoted to forest understories where the vast majority (>75%) of the vascular species reside. Here we test the hypothesis that the reintroduction of disturbances resembling historic disturbance regimes and moderate levels of ungulate browsing enhance plant diversity. We explore whether once-common disturbances and their interaction with the top-down influence of browsers can create conditions favorable for the maintenance of a rich herbaceous layer in a region recognized as a temperate biodiversity hotspot in West Virginia, U.S.A. We tested this hypothesis via a factorial experiment whereby we manipulated canopy gaps (presence/absence) of a size typically found in old-growth stands, low-intensity understory fire (burned/unburned), and deer browsing (fenced/unfenced). We tracked the abundance and diversity of more than 140 herb species for six years. Interactions among our treatments were pervasive. The combination of canopy gaps and understory fire increased herbaceous layer richness, cover, and diversity well beyond either disturbance alone. Furthermore, we documented evidence that deer at moderate levels of abundance promote herbaceous richness and abundance by preferentially browsing fast-growing pioneer species that thrive following co-occurring disturbances (i.e., fire and gaps). This finding sharply contrasts with the negative impact browsers have when their populations reach levels well beyond those that occurred for centuries. Although speculative, our results suggest that

  13. Isolation and characterization of microsatellite loci for the herbaceous tuber crop, Amorphophallus konjac (Araceae).

    Science.gov (United States)

    Pan, C; You, Y N; Diao, Y; Hu, Z L; Chen, J M

    2012-12-19

    Amorphophallus konjac is an herbaceous tuber crop with tremendous potential for commercial development. We report the development of microsatellite primers for this important crop species. Thirteen polymorphic microsatellite markers were developed and tested in two populations of A. konjac from the Wuling Mountain Region (WL population) and the Yunnan Province (YN population) in China. The number of alleles per locus ranged from 1 to 7; the observed and expected heterozygosities ranged from 0 to 1 and from 0 to 0.844, respectively, in the two populations. These microsatellite markers will facilitate further studies in population genetics and utilization of A. konjac.

  14. The monitoring of herbaceous seeds in the 30-km zone of the Chernobyl nuclear accident

    Energy Technology Data Exchange (ETDEWEB)

    Taskaev, A.I.; Frolova, N.P.; Popova, O.N.; Shevchenko, V.A. (AN SSSR, Syktyvkar (Russian Federation). Komi Filial AN SSSR, Moscow (Russian Federation). Inst. Obshchej Genetiki)

    1992-02-01

    Species of wild herbaceous plants growing over a period of 3 years under chronic irradiation resulting from the Chernobyl accident were studied. Examining the mass of 1000 seeds and their germination did not yield any significant differences between groups of seeds of the same species collected from the different contaminated zones. Nor did the frequency of aberrant cells in roots of germinated seeds reveal any significant differences between the zones. Seeds of Plantago lanceolata growing in areas with higher levels of radiation, did appear to be more sensitive to additional gamma-irradiation. (author). 5 refs.; 7 figs.; 5 tabs.

  15. Designer ecosystems

    NARCIS (Netherlands)

    Awasthi, Ashutosh; Singh, Kripal; O'Grady, Audrey; Courtney, Ronan; Kalra, Alok; Singh, Rana Pratap; Cerda Bolinches, Artemio; Steinberger, Yosef; Patra, D.D.

    2016-01-01

    Increase in human population is accelerating the rate of land use change, biodiversity loss and habitat degradation, triggering a serious threat to life supporting ecosystem services. Existing strategies for biological conservation remain insufficient to achieve a sustainable human-nature relatio

  16. Obscuring ecosystem function with application of the ecosystem services concept.

    Science.gov (United States)

    Peterson, Markus J; Hall, Damon M; Feldpausch-Parker, Andrea M; Peterson, Tarla Rai

    2010-02-01

    enables the social and political changes required to ensure valuation of ecosystem functions and related biodiversity in ways beyond their measurement on an economic scale.

  17. Water level effect on herbaceous plant assemblages at an artificial reservoir-Lago Azul State Park, Southern Brazil.

    Science.gov (United States)

    Souza, D C; Ferreira, J D; Bueno, P A A; Iwakura, L; Bueno, R O; Campiolo, J B

    2015-12-01

    This study presents the effect of water level variation on the assemblages of herbaceous species in Mourão I Reservoir, Lago Azul State Park, Southern Brazil. The structure and distribution of populations was examined in February (dry period) and April (rainy period), 2011, in two transects. These transects started at the forest edge towards the center of the lake. The end of the transect coincided with the end of the plants within the lake. On every two meters along of the transects we sampled a wooden square of 0.25 m(2) for species biomass analysis.The macrophyte stand was composed entirely of emergent species. Considering the periods, most species were less frequent in the rainy period (April), but Ipomea ramosissima (Poir.) Choisy, Commelina nudiflora L., Eleocharis acuntagula (Roxb.) Schult. and Verbena litorales (Kunth.) had their frequency increased during this period, probably due to their resistance. The influence of flood as measured by the NMDS point out that both before and after the flood, there are plots with distinct compositions and biomass. The water level variation affects the dynamics of plant composition and structure in marginal areas of the Reservoir.

  18. Water level effect on herbaceous plant assemblages at an artificial reservoir-Lago Azul State Park, Southern Brazil

    Directory of Open Access Journals (Sweden)

    D. C. Souza

    Full Text Available This study presents the effect of water level variation on the assemblages of herbaceous species in Mourão I Reservoir, Lago Azul State Park, Southern Brazil. The structure and distribution of populations was examined in February (dry period and April (rainy period, 2011, in two transects. These transects started at the forest edge towards the center of the lake. The end of the transect coincided with the end of the plants within the lake. On every two meters along of the transects we sampled a wooden square of 0.25 m2 for species biomass analysis.The macrophyte stand was composed entirely of emergent species. Considering the periods, most species were less frequent in the rainy period (April, but Ipomea ramosissima (Poir. Choisy, Commelina nudiflora L., Eleocharis acuntagula (Roxb. Schult. and Verbena litorales (Kunth. had their frequency increased during this period, probably due to their resistance. The influence of flood as measured by the NMDS point out that both before and after the flood, there are plots with distinct compositions and biomass. The water level variation affects the dynamics of plant composition and structure in marginal areas of the Reservoir.

  19. Energy and Water Fluxes in Heterogeneous Mediterranean Water-limited Ecosystems

    Science.gov (United States)

    Detto, M.; Katul, G.; Mancini, M.

    2005-12-01

    Research efforts in distributed eco-hydrologic models often fall in one of two categories: prognostic, in which predictions of root-zone soil moisture content and land surface fluxes is required for a projected radiative and precipitation forcing time series, or diagnostic in which the relationship between soil water status and atmospheric water vapor demand is to be derived for the various components of the landscape. The latter relationships are now receiving broad attention in climate change, hydrological, and ecological studies of arid and semi-arid ecosystems. This interest is now a central focus given the recognition that the component latent heat flux sensitivity to soil moisture decline can directly impact plant productivity, carbon and nutrient cycling, and ground water recharge. With projected shifts in precipitation statistics, mainly towards increased desertification, the "stability" of these ecosystems is highly dependent on their ability to uptake water at low soil moisture Here, we determine the relationship between soil water status and atmospheric water vapor demand for patchy landscapes within a semi-arid ecosystems using a combination remote sensing products and field experiments. In particular, we investigate how VIS/NIR measurements, in conjunction with standard micrometeorological data and ground based thermal infrared thermometers, provide "diagnostic" hydrologic relationship between soil water content and potential evapo-transpiration for the various components of the landscape. These experiments were conducted in the Orroli site, situated in the mid-west of Sardinia (Italy) within the Flumendosa river watershed, which is considered one of the most important water supply resources to the island. The landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives (/Olea sylvestris/) and cork oaks (/Quercus suber/), different shrubs (/Asparagus acutifolius, Rubus ulmifolius/) and herbaceous species (/Asphodelus

  20. A Database of Herbaceous Vegetation Responses to Elevated Atmospheric CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Jones, M.H.

    1999-11-24

    To perform a statistically rigorous meta-analysis of research results on the response by herbaceous vegetation to increased atmospheric CO{sub 2} levels, a multiparameter database of responses was compiled from the published literature. Seventy-eight independent CO{sub 2}-enrichment studies, covering 53 species and 26 response parameters, reported mean response, sample size, and variance of the response (either as standard deviation or standard error). An additional 43 studies, covering 25 species and 6 response parameters, did not report variances. This numeric data package accompanies the Carbon Dioxide Information Analysis Center's (CDIAC's) NDP-072, which provides similar information for woody vegetation. This numeric data package contains a 30-field data set of CO{sub 2}-exposure experiment responses by herbaceous plants (as both a flat ASCII file and a spreadsheet file), files listing the references to the CO{sub 2}-exposure experiments and specific comments relevant to the data in the data sets, and this documentation file (which includes SAS{reg_sign} and Fortran codes to read the ASCII data file). The data files and this documentation are available without charge on a variety of media and via the Internet from CDIAC.

  1. Effects of fertilization on population density and productivity of herbaceous plants in desert steppe

    Institute of Scientific and Technical Information of China (English)

    JieQiong Su; XinRong Li; HaoTian Yang

    2014-01-01

    In order to investigate the impacts of fertilization on population density and productivity on herbaceous plants in desert steppe, nitrogen (N), phosphorus (P), and N-P addition experiments were performed. Each fertilizer treatment included four addition levels, i.e., 0, 5, 10, and 20 g/m2. The results indicated that population density decreased as fertilization levels increased regardless of the sort of fertilizer. More specifically, total density as well as density of Artemisia capillaris, Al-lium polyrhizum, and Enneapogon brachystachyus decreased significantly in 20 g/m2 treated plots, as compared with the control plots. Fertilization effects on aboveground and root biomasses were extremely similar to that found in population density; that is, both total aboveground biomass and aboveground biomasses for A. capillaris, A. polyrhizum, and E. brachystachyus were negatively correlated with increasing fertilization levels, with all determination coefficients (R2) greater than 0.80. Therefore, in the case of desert regions (annual precipitation <180 mm), fertilization would inhibit population density and productivity of herbaceous plants.

  2. Assessing radiation exposure of herbaceous plant species at the East-Ural Radioactive Trace.

    Science.gov (United States)

    Karimullina, Elina; Antonova, Elena; Pozolotina, Vera

    2013-10-01

    The East-Ural Radioactive Trace (EURT) is a result of the Mayak Production Association accident that occurred in 1957 in Russia. Radiological assessment improves the interpretation of biological effects of exposure to ionizing radiation. Therefore a modeling approach was used to estimate dose rates on Leonurus quinquelobatus, Silene latifolia, Stellaria graminea and Bromus inermis. Soil-to-organism transfer parameter values are delivered from empirical data of (90)Sr and (137)Cs soil and vegetative plant mass activity concentrations. External and internal whole-body dose rates were calculated using deterministic (The ERICA Tool-Tier 2 and R&D 128/SP1a) and probabilistic (The ERICA Tool-Tier 3) methods. The total dose rate for herbs was under 100 μGy h(-1) at the most polluted site. The total absorbed dose rates increased 43-110 times (Tier 3) for different herbaceous plant species along the pollution gradient. Based on these data, it can be concluded that herbaceous plant populations currently exist under low-level chronic exposure at the EURT area. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Fossil evidence for a herbaceous diversification of early eudicot angiosperms during the Early Cretaceous.

    Science.gov (United States)

    Jud, Nathan A

    2015-09-07

    Eudicot flowering plants comprise roughly 70% of land plant species diversity today, but their early evolution is not well understood. Fossil evidence has been largely restricted to their distinctive tricolpate pollen grains and this has limited our understanding of the ecological strategies that characterized their primary radiation. I describe megafossils of an Early Cretaceous eudicot from the Potomac Group in Maryland and Virginia, USA that are complete enough to allow reconstruction of important life-history traits. I draw on quantitative and qualitative analysis of functional traits, phylogenetic analysis and sedimentological evidence to reconstruct the biology of this extinct species. These plants were small and locally rare but widespread, fast-growing herbs. They had complex leaves and they were colonizers of bright, wet, disturbance-prone habitats. Other early eudicot megafossils appear to be herbaceous rather than woody, suggesting that this habit was characteristic of their primary radiation. A mostly herbaceous initial diversification of eudicots could simultaneously explain the heretofore sparse megafossil record as well as their rapid diversification during the Early Cretaceous because the angiosperm capacity for fast reproduction and fast evolution is best expressed in herbs. © 2015 The Author(s).

  4. EASTERN DODDER (CUSCUTA MONOGYNA VAHL.) SEED GERMINATION AFFECTED BY SOME HERBACEOUS DISTILLATES.

    Science.gov (United States)

    Movassaghi, M; Hassannejad, S

    2015-01-01

    Eastern dodder (Cuscuta monogyna Vahl.) is one of the noxious parasitic weeds that infected many ornamental trees in green spaces and gardens. Our purpose is to find natural inhibitors for prevention of its seed germination. In order to reach this aim, laboratory studies were conducted by using of herbaceous distillates of Dracocephalum moldavica, Nasturtium officinalis, Malva neglecta, Mentha piperita, Mentha pulegium, Rosa damascene, Ziziphora tenuior, and Urtica dioica on seed germination of C. monogyna. Z. tenuior distillate stimulated C. monogyna seed germination, whereas others reduced this parasitic weed's seed germination. D. moldavica caused maximum inhibition on weed seed germination. Seedling growth of C. monogyna was more affected than its seed germination. All of these herbaceous distillates reduced C. monogyna seedling length so that the latter decreased from 28.2 mm in distilled water to 4.5, 3.97, 3.85, 3.67, 3.1, 2.87, 2.57, 1.9, and 1.17 in M. pulegium, M. piperita, F. officinalis, Z. tenuior, N. officinalis, M. neglecta, R. damascene, U. dioica and D. moldavica, respectively. By using these medicinal plants distillates instead of herbicides, the parasitic weed seedling length and host plant infection will reduce.

  5. Herbaceous energy crops: planning for a renewed commitment. [Hay, silage, rapeseed, sugar and starch crops, hydrocarbon crops

    Energy Technology Data Exchange (ETDEWEB)

    Berger, B.J.; Cushman, J.H.

    1984-01-01

    In 1984, the US Department of Energy's Biomass Energy Technology Division (BETD) began a new program of research on the production of herbaceous crops for energy. In addition to the new Herbaceous Energy Crops (HEC) Program, ongoing BETD programs involve woody and aquatic energy crops. The goal of the HEC Program is to provide the technology base that will allow industry to develop commercially viable species and systems in order to produce herbaceous biomass for fuels and energy feedstocks. The program will concentrate on crop types that can contribute the most to energy supplies while minimizing the impact of producing energy from crops on food production and the environment. Research in the HEC Program will focus on crops suitable for marginal croplands and on winter crops that can be grown between plantings of conventional crops. 1 table.

  6. Linking trace gas measurements and molecular tracers of organic matter in aerosols for identification of ecosystem sources and types of wildfires in Central Siberia

    Science.gov (United States)

    Panov, A. V.; Prokushkin, A. S.; Korets, M. A.; Bryukhanov, A. V.; Myers-Pigg, A. N.; Louchouarn, P.; Sidenko, N. V.; Amon, R.; Andreae, M. O.; Heimann, M.

    2016-11-01

    Summer 2012 was one of the extreme wildfire years in Siberia. At the surface air monitoring station “ZOTTO” (60°48'N, 89°21'E, 114 m a.s.l.) in Central Siberia we observed biomass burning (BB) influence on the ongoing atmospheric measurements within more than 50 % of the time in June-July 2012 that indicates a 30 times greater wildfire signal compared to previously reported ordinary biomass burning signature for the study area. While previous studies thoroughly estimated a relative input of BB into aerosol composition (i.e. size distribution, physical and optical parameters etc.) at ZOTTO, in this paper we characterize the source apportionment of the smoke aerosols with molecular tracer techniques from large-scale wildfires occurred in 2012 in the two prevailing types of Central Siberian ecosystems: complexes of pine forests and bogs and dark coniferous forests. Wildfires in the selected ecosystems are highly differed by their combustion phase (flaming/smoldering), the type of fire (crown/ground), biomass fuel, and nature of soil that greatly determines the smoke particle composition. Anhydrosugars (levoglucosan and its isomers) and lignin phenols taken as indicators of the sources and the state of particulate matter (PM) inputs in the specific fire plumes were used as powerful tools to compare wildfires in different environmental conditions and follow the role and contribution of different sources of terrestrial organic matter in the transport of BB pollutants into the pristine atmosphere of boreal zone in Central Siberia.

  7. Inter-annual Variability of Evapotranspiration in a Semi-arid Oak-savanna Ecosystem: Measured and Modeled Buffering to Precipitation Changes

    Science.gov (United States)

    Raz-Yaseef, N.; Sonnentag, O.; Kobayashi, H.; Baldocchi, D. D.

    2010-12-01

    Precipitation (P) is the primary control on vegetation dynamics and productivity, implying that climate induced disturbances in frequency and timing of P are intimately coupled with fluxes of carbon, water and energy. Future climate change is expected to increase extreme rainfall events as well as droughts, suggesting linked vegetation changes to an unknown extent. Semi-arid climates experience large inter-annual variability (IAV) in P, creating natural conditions adequate to study how year-to-year changes in P affect atmosphere-biosphere fluxes. We used a 10-year flux database collected at a semi-arid savanna site in order to: (1) define IAV in P by means of frequency and timing; (2) investigate how changes in P affect the ecohydrology of the forest and its partitioning into the main vapor fluxes, and (3) evaluate model capability to predict IAV of carbon and water fluxes above and below the canopy. This is based on the perception that the capability of process-oriented models to construct the deviation, and not the average, is important in order to correctly predict ecosystem sensitivity to climate change. Our research site was a low density and low LAI (0.8) semi-arid (P=523±180 mm yr-1) savanna site, combined of oaks and grass, and located at Tonzi ranch, California. Measurements of carbon and water fluxes above and below the tree canopy using eddy covariance and supplementary measurements have been made since 2001. Measured fluxes were compared to modeled based on two bio-meteorological process-oriented ecosystem models: BEPS and 3D-CAONAK. Our results show that IAV in P was large, and standard deviation (STD) was 38% of the average. Accordingly, the wet soil period (measured volumetric water content > 8%) varied between 156 days in dry years to 301 days in wet years. IAV of the vapor fluxes were lower than that of P (STD was 17% for the trees and 23% for the floor components), suggesting on ecosystem buffering to changes in P. The timing of grass green up

  8. The nutritional quality of herbaceous legumes on goats: Intake, digestibility and nitrogen balances

    Directory of Open Access Journals (Sweden)

    Simon P Ginting

    2005-12-01

    Full Text Available The availability of forages is a critical factor that determine the sustainability of the animal-plantation production system. In this typical production system, cover crops could be an important sources of forages to support the animal production. The study is aimed to evaluate the nutritional quality (chemical compositions, intake, digestibility and N balances of herbaceous legumes namely Arachis pintoi and Arachis glabrata having potential for used as alternative cover crops in plantation. Centerocema pubescens, a conventional cover crops used in plantation, was used as control. Twenty-one mature male goats (16-18 kg were used in this experiment. The animals were put in individual metabolism cages, divided into three groups (7 animal per group based on the body weight, and were randomly allocated into one of the three forages. The experiment was run in a Completely Randomized Design. The animals were allocated to an adaptation period for 14 days, followed by intake measurement for 5 days and fecal and urine collection for the next 7 days. During the fecal and urine collection forages were offered at 90% of the maximum intake. Chemical analyses showed that the DM and OM contents were relatively equal among the forages, but the crude protein content of C. pubescens (23.56% are relatively higher than those of A. pintoi (16.94% or of A. glabrata (15.19% The fiber (NDF content was also relatively higher in C. pubescens (59.37% than in A. pintoi (16.94% or A. glabrata (41.50%. The forage intake was highest (P0.05 between goats fed A. pintoi (466 g/d or A. glabrata (453 g/d. A similar trend was seen when intake was expressed as % BW (3.80, 3.50 and 3.40, respectively or as g/kg BW0.75 (42.4, 39.5 and 38.4, respectively. The digestion coeficient of DM (81.3% or OM (83.5% were highest (P0.05 between A. glabrata (71.9 and 73.2%, respectively and C. pubescens (73.7 and 74.2%, respectively. The trends were the same with the digestion coeficient of ADF

  9. Eddy covariance flux measurements of net ecosystem carbon dioxide exchange from a lowland peatland flux tower network in England and Wales

    Science.gov (United States)

    Morrison, Ross; Balzter, Heiko; Burden, Annette; Callaghan, Nathan; Cumming, Alenander; Dixon, Simon; Evans, Jonathan; Kaduk, Joerg; Page, Susan; Pan, Gong; Rayment, Mark; Ridley, Luke; Rylett, Daniel; Worrall, Fred; Evans, Christopher

    2016-04-01

    Peatlands store disproportionately large amounts of soil carbon relative to other terrestrial ecosystems. Over recent decades, the large amount of carbon stored as peat has proved vulnerable to a range of land use pressures as well as the increasing impacts of climate change. In temperate Europe and elsewhere, large tracts of lowland peatland have been drained and converted to agricultural land use. Such changes have resulted in widespread losses of lowland peatland habitat, land subsidence across extensive areas and the transfer of historically accumulated soil carbon to the atmosphere as carbon dioxide (CO2). More recently, there has been growth in activities aiming to reduce these impacts through improved land management and peatland restoration. Despite a long history of productive land use and management, the magnitude and controls on greenhouse gas emissions from lowland peatland environments remain poorly quantified. Here, results of surface-atmosphere measurements of net ecosystem CO2 exchange (NEE) from a network of seven eddy covariance (EC) flux towers located at a range of lowland peatland ecosystems across the United Kingdom (UK) are presented. This spatially-dense peatland flux tower network forms part of a wider observation programme aiming to quantify carbon, water and greenhouse gas balances for lowland peatlands across the UK. EC measurements totalling over seventeen site years were obtained at sites exhibiting large differences in vegetation cover, hydrological functioning and land management. The sites in the network show remarkable spatial and temporal variability in NEE. Across sites, annual NEE ranged from a net sink of -194 ±38 g CO2-C m-2 yr-1 to a net source of 784±70 g CO2-C m-2 yr-1. The results suggest that semi-natural sites remain net sinks for atmospheric CO2. Sites that are drained for intensive agricultural production range from a small net sink to the largest observed source for atmospheric CO2 within the flux tower network

  10. Multivariate Spatio-Temporal Clustering: A Framework for Integrating Disparate Data to Understand Network Representativeness and Scaling Up Sparse Ecosystem Measurements

    Science.gov (United States)

    Hoffman, F. M.; Kumar, J.; Maddalena, D. M.; Langford, Z.; Hargrove, W. W.

    2014-12-01

    Disparate in situ and remote sensing time series data are being collected to understand the structure and function of ecosystems and how they may be affected by climate change. However, resource and logistical constraints limit the frequency and extent of observations, particularly in the harsh environments of the arctic and the tropics, necessitating the development of a systematic sampling strategy to maximize coverage and objectively represent variability at desired scales. These regions host large areas of potentially vulnerable ecosystems that are poorly represented in Earth system models (ESMs), motivating two new field campaigns, called Next Generation Ecosystem Experiments (NGEE) for the Arctic and Tropics, funded by the U.S. Department of Energy. Multivariate Spatio-Temporal Clustering (MSTC) provides a quantitative methodology for stratifying sampling domains, informing site selection, and determining the representativeness of measurement sites and networks. We applied MSTC to down-scaled general circulation model results and data for the State of Alaska at a 4 km2 resolution to define maps of ecoregions for the present (2000-2009) and future (2090-2099), showing how combinations of 37 bioclimatic characteristics are distributed and how they may shift in the future. Optimal representative sampling locations were identified on present and future ecoregion maps, and representativeness maps for candidate sampling locations were produced. We also applied MSTC to remotely sensed LiDAR measurements and multi-spectral imagery from the WorldView-2 satellite at a resolution of about 5 m2 within the Barrow Environmental Observatory (BEO) in Alaska. At this resolution, polygonal ground features—such as centers, edges, rims, and troughs—can be distinguished. Using these remote sensing data, we up-scaled vegetation distribution data collected on these polygonal ground features to a large area of the BEO to provide distributions of plant functional types that can

  11. Herbaceous Plants for Climate Adaptation and Intensely Developed Urban Sites In Northern Europe: A Case Study From the Eastern Romanian Steppe

    Directory of Open Access Journals (Sweden)

    Sjöman Henrik

    2015-03-01

    Full Text Available In the increasingly compact city, services currently provided for in parks will in future be compressed into smaller green unit-structures, often associated with paved surfaces. Left-over spaces in urban environments, such as traffic roundabouts and strips along paths, roads and other corridors, will be important in the future city in order to deliver different eco-system services, especially stormwater management. It is therefore essential to start now to develop the knowledge and experience needed to create sustainable plantings for these sites. This paper presents the findings of a field survey in eastern Romania that sought to identify potential species for urban paved plantings in the Scandinavian region (northern Europe. The research approach is rooted in the hypothesis that studies of natural vegetation systems and habitats where plants are exposed to environmental conditions similar to those in inner-city environments can: 1 identify new or non-traditional species and genotypes adapted to urban environments; and 2 supply information and knowledge about their use potential concerning growth, flowering, life form, etc. In total, 117 different herbaceous species, all of which experience water stress regimes comparable to those in urban paved sites in Scandinavia. The initial information obtained from this field survey present a base of knowledge of which species that have a future potential for use in urban environment, which is of great importance in the following work within this project instead of testing species randomly without this knowledge of the species tolerance and performance in similar habitats.

  12. Genetic Improvement of Switchgrass and Other Herbaceous Plants for Use as Biomass Fuel Feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, K.P.

    2001-01-11

    It should be highly feasible to genetically modify the feedstock quality of switchgrass and other herbaceous plants using both conventional and molecular breeding techniques. Effectiveness of breeding to modify herbages of switchgrass and other perennial and annual herbaceous species has already been demonstrated. The use of molecular markers and transformation technology will greatly enhance the capability of breeders to modify the plant structure and cell walls of herbaceous plants. It will be necessary to monitor gene flow to remnant wild populations of plants and have strategies available to curtail gene flow if it becomes a potential problem. It also will be necessary to monitor plant survival and long-term productivity as affected by genetic changes that improve forage quality. Information on the conversion processes that will be used and the biomass characteristics that affect conversion efficiency and rate is absolutely essential as well as information on the relative economic value of specific traits. Because most forage or biomass quality characteristics are highly affected by plant maturity, it is suggested that plant material of specific maturity stages be used in research to determining desirable feedstock quality characteristics. Plant material could be collected at various stages of development from an array of environments and storage conditions that could be used in conversion research. The same plant material could be used to develop NIRS calibrations that could be used by breeders in their selection programs and also to develop criteria for a feedstock quality assessment program. Breeding for improved feedstock quality will likely affect the rate of improvement of biomass production per acre. If the same level of resources are used, multi-trait breeding simply reduces the selection pressure and hence the breeding progress that can be made for a single trait unless all the traits are highly correlated. Since desirable feedstock traits are likely

  13. Defining ecosystem assets for natural capital accounting

    NARCIS (Netherlands)

    Hein, Lars; Bagstad, Ken; Edens, Bram; Obst, Carl; Jong, de Rixt; Lesschen, Jan Peter

    2016-01-01

    In natural capital accounting, ecosystems are assets that provide ecosystem services to people. Assets can be measured using both physical and monetary units. In the international System of Environmental-Economic Accounting, ecosystem assets are generally valued on the basis of the net present va

  14. The impact of the provision of water for game on the basal cover of the herbaceous vegetation around a dam in the Kruger National Park

    Directory of Open Access Journals (Sweden)

    I. Thrash

    1991-09-01

    Full Text Available A line intercept survey was done on the herbaceous vegetation in permanently marked plots at distance intervals from the Wik-en-Weeg Dam, Kruger National Park, in 1973. The survey was repeated in 1990 so that changes in basal cover could be determined in relation to distance from the dam. Positive relationships with distance from the dam were found for the relative total percentage basal cover of the herbaceous vegetation, as well as for the relative basal cover of, respectively, grasses, forbs, decreasers and increasers. It was concluded that the provision of a permanent supply of drinking water for game in the Wik-en-Weeg Dam has had an impact on the nearby herbaceous community basal cover composition, as well as a negative impact on the basal cover of the herbaceous vegetation in the vicinity. The basal cover of the herbaceous stratum was more sensitive to the effect of the dam than parameters of the woody stratum.

  15. Quick Measurement of CH4, CO2 and N2O Emissions from a Short-Plant Ecosystem

    Institute of Scientific and Technical Information of China (English)

    王跃思; 王迎红

    2003-01-01

    Combining improved injector, gas line and valve-driving models, a gas chromatograph (GC) equippedwith Hydrogen Flame Ionization Detector (FID) and Electron Capture Detector (ECD), can measureCH4, CO2, and N2O simultaneously in an air sample in four minutes. Test results show that the systemhas high sensitivity, resolution, and precision; the linear response range of the system meets the requirementof flux measurements in situ. The system is suitable for monitoring fluxes of the main greenhouse gases ina short-plant field since it is easy to use, efficacious, and constant and reliable in collecting data.

  16. Evaluation of the Relative Merits of Herbaceous and Woody Crops for Use in Tunable Thermochemical Processing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joon-Hyun [Ceres, Inc., Thousand Oaks, CA (United States); Martinalbo, Ilya [Choren USA, LLC, Houston, TX (United States)

    2011-12-01

    This report summarizes the work and findings of the grant work conducted from January 2009 until September 2011 under the collaboration between Ceres, Inc. and Choren USA, LLC. This DOE-funded project involves a head-to-head comparison of two types of dedicated energy crops in the context of a commercial gasification conversion process. The main goal of the project was to gain a better understanding of the differences in feedstock composition between herbaceous and woody species, and how these differences may impact a commercial gasification process. In this work, switchgrass was employed as a model herbaceous energy crop, and willow as a model short-rotation woody crop. Both crops are species native to the U.S. with significant potential to contribute to U.S. goals for renewable liquid fuel production, as outlined in the DOE Billion Ton Update (http://www1.eere.energy.gov/biomass/billion_ton_update.html, 2011). In some areas of the U.S., switching between woody and herbaceous feedstocks or blending of the two may be necessary to keep a large-scale gasifier operating near capacity year round. Based on laboratory tests and process simulations it has been successfully shown that suitable high yielding switchgrass and willow varieties exist that meet the feedstock specifications for large scale entrained flow biomass gasification. This data provides the foundation for better understanding how to use both materials in thermochemical processes. It has been shown that both switchgrass and willow varieties have comparable ranges of higher heating value, BTU content and indistinguishable hydrogen/carbon ratios. Benefits of switchgrass, and other herbaceous feedstocks, include its low moisture content, which reduce energy inputs and costs for drying feedstock. Compared to the typical feedstock currently being used in the Carbo-V® process, switchgrass has a higher ash content, combined with a lower ash melting temperature. Whether or not this may cause inefficiencies in the

  17. Taxonomic revision and distribution of herbaceous Paramollugo (Molluginaceae in the Eastern Hemisphere

    Directory of Open Access Journals (Sweden)

    Alexander P. Sukhorukov

    2016-10-01

    Full Text Available The genus Paramollugo with the type species Paramollugo nudicaulis (≡Mollugo nudicaulis has recently been described after molecular investigations. Here we report two new endemic Malagasy species: Paramollugo simulans and P. elliotii, and transfer a forgotten New Caledonian endemic Mollugo digyna to Paramollugo (P. digyna. Consequently, the number of Paramollugo species in the Eastern Hemisphere is increased from three to six. Almost all genus representatives (except P. nudicaulis, which has a wide distribution in Southern Asia, Arabia and tropical Africa are endemic to Madagascar, Somalia, or New Caledonia. Since the type of seed coat ornamentation is crucial for species delimitation, a diagnostic key with new taxonomically significant carpological characters and other new traits is provided for all the herbaceous Paramollugo. The distribution patterns of P. nudicaulis s.str., P. simulans and P. elliotii are presented.

  18. Impact factors identification of spatial heterogeneity of herbaceous plant diversity on five southern islands of Miaodao Archipelago in North China

    Science.gov (United States)

    Chi, Yuan; Shi, Honghua; Wang, Xiaoli; Qin, Xuebo; Zheng, Wei; Peng, Shitao

    2016-09-01

    Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity. Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patterns. Five southern islands in the Miaodao Archipelago, North China were studied herein. The spatial distribution of herbaceous plant diversity on these islands was analyzed, and the impact factors and their degree of impact on spatial heterogeneity were identified using CCA ordination and ANOVA. The results reveal 114 herbaceous plant species, belonging to 94 genera from 34 families in the 50 plots sampled. The total species numbers on different islands were significantly positively correlated with island area, and the average α diversity was correlated with human activities, while the β diversity among islands was more affected by island area than mutual distances. Spatial heterogeneity within islands indicated that the diversities were generally high in areas with higher altitude, slope, total nitrogen, total carbon, and canopy density, and lower moisture content, pH, total phosphorus, total potassium, and aspect. Among the environmental factors, pH, canopy density, total K, total P, moisture content, altitude, and slope had significant gross effects, but only canopy density exhibited a significant net effect. Terrain affected diversity by restricting plantation, plantation in turn influenced soil properties and the two together affected diversity. Therefore, plantation was ultimately the fundamental driving factor for spatial heterogeneity in herbaceous plant diversity on the five islands.

  19. Response of loblolly pine to complete woody and herbaceous control: projected yields and economic outcomes - the COMProject

    Science.gov (United States)

    James H. Miller; R.L. Busby; B.R. Zutter; S.M. Zedaker; M.B. Edwards; R.A. Newbold

    1995-01-01

    Abstract.Age-8 and -9 data from the 13 study plantations of the Competition Omission Monitoring Project (COMP) were used to project yields and derive economic outcomes for loblolly pine (Pinus taeda L.). COMP treatments were chop-burn, complete woody plant control, complete herbaceous plant control for 4 years, and complete woody...

  20. Adapting to change in banana-based farming systems of northwest Tanzania: the potential role of herbaceous legumes

    NARCIS (Netherlands)

    Baijukya, F.P.

    2004-01-01

    Keywords: Land use changes; Herbaceous legumes; Adoptability; N 2 -fixation; Residual effect; Legume management; Exploration of options, Nutrient depleted soils.The banana-based farming system in

  1. Effects of Dichrostachys cinerea (l. Wight & Arn (Fabaceae on herbaceous species in a semi-arid rangeland in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Clarice Mudzengi

    2014-08-01

    Full Text Available Anthropogenic alteration of an environment and other disturbance regimes may enable the expansion of some native species into new geographical areas, a phenomenon observed with Dichrostachys cinerea. Five D. cinerea invaded sites, each approximately one hectare in size were assessed for the effects of D. cinerea on native herbaceous species diversity, richness, basal cover, litter cover, top hamper and plant vigour. The same attributes were studied in five uninvaded sites adjacent to, and equal in size to each invaded site. Forty herbaceous species were identified in the area. There were significant differences (P < 0.05 noted in species richness, basal cover, litter cover, top hamper, plant vigour, and species diversities between invaded and uninvaded sites, with uninvaded sites recording higher values than invaded sites. Altitude, erosion and the edaphic variables pH, N, P and K, which were included as explanatory variables, also differed significantly (P<0.05 between invaded and uninvaded sites. Of the 30 D. cinerea invaded plots established for herbaceous species assessments, 26 were positively correlated with altitude, erosion, pH, P, N and K. It is imperative to find ways of managing D. cinerea in order to reduce its adverse effects on herbaceous species.

  2. The cost of silage harvest and transport systems for herbaceous crops

    Energy Technology Data Exchange (ETDEWEB)

    Turhollow, A.; Downing, M.; Butler, J.

    1996-12-31

    Some of the highest yielding herbaceous biomass crops are thick-stemmed species such as energy cane (Saccharum ssp.), Napiergrass (Pennisetum purpureum), and forage sorghum (Sorghum bicolor). Their relatively high moisture content necessitates they be handled and stored as silage rather than hay bales or modules. This paper presents estimated costs of harvesting and transporting herbaceous crops as silage. Costs are based on an engineering-economic approach. Equipment costs are estimated by combining per-hour costs with the hours required to complete the operation. Harvest includes severing, chopping, and blowing stalks into a wagon or track. For 50% moisture content, in-field costs using trucks in the field (options 0 and 1) are $3.72-$5.99/dry Mg ($3.37-$5.43/dt) for a farmer and $3.09-$3.64/dry Mg ($2.81- $3.30/dt) for custom operators. However, slopes and wet field conditions may not permit trucks to enter the field. Direct-cut harvest systems using wagons to haul silage to trucks waiting at the field edge (option 2) are $8.52-$11.94/dry Mg ($7.73-$10.83/dt) for farmers and $7.20-$7.36/dry Mg ($6.53-$6.68/dt) for custom operators. Based on four round trips per 8-hour day, 50% and 70% moisture silage, truck transport costs are $8.37/dry Mg ($ 7.60/dt) and $13.98/dry Mg ($12.68/dt), respectively. Lower yields, lower hours of machine use, or a higher discount rate result in higher costs.

  3. Diversity and composition of herbaceous angiosperms along gradients of elevation and forest-use intensity.

    Science.gov (United States)

    Gómez-Díaz, Jorge Antonio; Krömer, Thorsten; Kreft, Holger; Gerold, Gerhard; Carvajal-Hernández, César Isidro; Heitkamp, Felix

    2017-01-01

    Terrestrial herbs are important elements of tropical forests; however, there is a lack of research on their diversity patterns and how they respond to different intensities of forest-use. The aim of this study was to analyze the diversity of herbaceous angiosperms along gradients of elevation (50 m to 3500 m) and forest-use intensity on the eastern slopes of the Cofre de Perote, Veracruz, Mexico. We recorded the occurrence of all herbaceous angiosperm species within 120 plots of 20 m x 20 m each. The plots were located at eight study locations separated by ~500 m in elevation and within three different habitats that differ in forest-use intensity: old-growth, degraded, and secondary forest. We analyzed species richness and floristic composition of herb communities among different elevations and habitats. Of the 264 plant species recorded, 31 are endemic to Mexico. Both α- and γ-diversity display a hump-shaped relation to elevation peaking at 2500 m and 3000 m, respectively. The relative contribution of between-habitat β-diversity to γ-diversity also showed a unimodal hump whereas within-habitat β-diversity declined with elevation. Forest-use intensity did not affect α-diversity, but β-diversity was high between old-growth and secondary forests. Overall, γ-diversity peaked at 2500 m (72 species), driven mainly by high within- and among-habitat β-diversity. We infer that this belt is highly sensitive to anthropogenic disturbance and forest-use intensification. At 3100 m, high γ-diversity (50 species) was driven by high α- and within-habitat β-diversity. There, losing a specific forest area might be compensated if similar assemblages occur in nearby areas. The high β-diversity and endemism suggest that mixes of different habitats are needed to sustain high γ-richness of terrestrial herbs along this elevational gradient.

  4. Developing population models: A systematic approach for pesticide risk assessment using herbaceous plants as an example.

    Science.gov (United States)

    Schmolke, Amelie; Kapo, Katherine E; Rueda-Cediel, Pamela; Thorbek, Pernille; Brain, Richard; Forbes, Valery

    2017-12-01

    Population models are used as tools in species management and conservation and are increasingly recognized as important tools in pesticide risk assessments. A wide variety of population model applications and resources on modeling techniques, evaluation and documentation can be found in the literature. In this paper, we add to these resources by introducing a systematic, transparent approach to developing population models. The decision guide that we propose is intended to help model developers systematically address data availability for their purpose and the steps that need to be taken in any model development. The resulting conceptual model includes the necessary complexity to address the model purpose on the basis of current understanding and available data. We provide specific guidance for the development of population models for herbaceous plant species in pesticide risk assessment and demonstrate the approach with an example of a conceptual model developed following the decision guide for herbicide risk assessment of Mead's milkweed (Asclepias meadii), a species listed as threatened under the US Endangered Species Act. The decision guide specific to herbaceous plants demonstrates the details, but the general approach can be adapted for other species groups and management objectives. Population models provide a tool to link population-level dynamics, species and habitat characteristics as well as information about stressors in a single approach. Developing such models in a systematic, transparent way will increase their applicability and credibility, reduce development efforts, and result in models that are readily available for use in species management and risk assessments. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Environmental quality assessment in estuarine ecosystems: use of biometric measurements and fecundity of the ragworm Nereis diversicolor (Polychaeta, Nereididae).

    Science.gov (United States)

    Durou, Cyril; Mouneyrac, Catherine; Amiard-Triquet, Claude

    2008-04-01

    The ability to cope with environmental stress may be expensive in terms of energy and this cost of tolerance is suspected to have negative counterparts such as reduced growth and fecundity. To date, condition indices based on biometric measurements are currently used in bivalves or fish but do not exist in endobenthic worms, despite their interest as bioindicators for the sedimentary compartment in which the major part of pollutants is stored in aquatic environments. In the present work, several biometric variables (jaw and total body length, number of segments, the length of the first three segments L3, wet or dry weight) were measured in the ragworm Nereis diversicolor originating from clean (Authie) and polluted (Seine) estuaries (France) to study size-weight relationships. The production of oocytes by females (which represent 80-90% of the population) was quantified in the same specimens. In females from the polluted site, the condition was shown to be altered and, in parallel, the production of oocytes was lower than in females from the comparatively clean site. From an operational point of view, we recommend the use of the length L3 and the wet weight. Because fecundity is mainly dependent on size and weight in N. diversicolor, biometric measurements would be useful tools for assessing the biological quality of estuarine sediments.

  6. Linking ecosystem characteristics to final ecosystem services for public policy.

    Science.gov (United States)

    Wong, Christina P; Jiang, Bo; Kinzig, Ann P; Lee, Kai N; Ouyang, Zhiyun

    2015-01-01

    Governments worldwide are recognising ecosystem services as an approach to address sustainability challenges. Decision-makers need credible and legitimate measurements of ecosystem services to evaluate decisions for trade-offs to make wise choices. Managers lack these measurements because of a data gap linking ecosystem characteristics to final ecosystem services. The dominant method to address the data gap is benefit transfer using ecological data from one location to estimate ecosystem services at other locations with similar land cover. However, benefit transfer is only valid once the data gap is adequately resolved. Disciplinary frames separating ecology from economics and policy have resulted in confusion on concepts and methods preventing progress on the data gap. In this study, we present a 10-step approach to unify concepts, methods and data from the disparate disciplines to offer guidance on overcoming the data gap. We suggest: (1) estimate ecosystem characteristics using biophysical models, (2) identify final ecosystem services using endpoints and (3) connect them using ecological production functions to quantify biophysical trade-offs. The guidance is strategic for public policy because analysts need to be: (1) realistic when setting priorities, (2) attentive to timelines to acquire relevant data, given resources and (3) responsive to the needs of decision-makers.

  7. [Effects of forest gap size and light intensity on herbaceous plants in Pinus koraiensis-dominated broadleaved mixed forest].

    Science.gov (United States)

    Duan, Wen-Biao; Wang, Li-Xia; Chen, Li-Xin; Du, Shan; Wei, Quan-Shuai; Zhao, Jian-Hui

    2013-03-01

    1 m x 1 m fixed quadrats were parallelly arranged with a space of 2 m in each of six forest gaps in Pinus koraiensis-dominated broadleaved mixed forest, taking the gap center as the starting point and along east-west and south-north directions. In each quadrat, the coverage and abundance of herbaceous plants at different height levels were investigated by estimation method in June and September 2011, and the matrix characteristics within the quadrats were recorded. Canopy analyzer was used to take fish-eye photos in the selected overcast days in each month from June to September, 2011, and the relative light intensity was calculated by using Gap Light Analyzer 2.0 software. The differences in the relative light intensity and herbaceous plants coverage and richness between different gaps as well as the correlations between the coverage of each species and the direct light, diffuse light, and matrix were analyzed. The results showed that in opening areas and under canopy, the relative light intensity in large gaps was higher than that in small gaps, and the variation ranges of diffuse light and direct light from gap center to gap edge were bigger in large gaps than in small gaps. The direct light reaching at the ground both in large gaps and in small gaps was higher in the north than in the south direction. In the Z1, Z2, Z3, and Z4 zones, both the coverage and the richness of herbaceous plants were larger in large gaps than in small gaps, and the differences of species richness between large and small gaps reached significant level. The coverage of the majority of the herbaceous plants had significant correlations with diffuse light and matrix, and only the coverage of a few herbaceous plants was correlated with direct light.

  8. Effects of Inflorescence Stem Structure and Cell Wall Components on the Mechanical Strength of Inflorescence Stem in Herbaceous Peony

    Directory of Open Access Journals (Sweden)

    Qingping Geng

    2012-04-01

    Full Text Available Herbaceous peony (Paeonia lactiflora Pall. is a traditional famous flower, but its poor inflorescence stem quality seriously constrains the development of the cut flower. Mechanical strength is an important characteristic of stems, which not only affects plant lodging, but also plays an important role in stem bend or break. In this paper, the mechanical strength, morphological indices and microstructure of P. lactiflora development inflorescence stems were measured and observed. The results showed that the mechanical strength of inflorescence stems gradually increased, and that the diameter of inflorescence stem was a direct indicator in estimating mechanical strength. Simultaneously, with the development of inflorescence stem, the number of vascular bundles increased, the vascular bundle was arranged more densely, the sclerenchyma cell wall thickened, and the proportion of vascular bundle and pith also increased. On this basis, cellulose and lignin contents were determined, PlCesA3, PlCesA6 and PlCCoAOMT were isolated and their expression patterns were examined including PlPAL. The results showed that cellulose was not strictly correlated with the mechanical strength of inflorescence stem, and lignin had a significant impact on it. In addition, PlCesA3 and PlCesA6 were not key members in cellulose synthesis of P. lactiflora and their functions were also different, but PlPAL and PlCCoAOMT regulated the lignin synthesis of P. lactiflora. These data indicated that PlPAL and PlCCoAOMT could be applied to improve the mechanical strength of P. lactiflora inflorescence stem in genetic engineering.

  9. Effects of inflorescence stem structure and cell wall components on the mechanical strength of inflorescence stem in herbaceous peony.

    Science.gov (United States)

    Zhao, Daqiu; Han, Chenxia; Tao, Jun; Wang, Jing; Hao, Zhaojun; Geng, Qingping; Du, Bei

    2012-01-01

    Herbaceous peony (Paeonia lactiflora Pall.) is a traditional famous flower, but its poor inflorescence stem quality seriously constrains the development of the cut flower. Mechanical strength is an important characteristic of stems, which not only affects plant lodging, but also plays an important role in stem bend or break. In this paper, the mechanical strength, morphological indices and microstructure of P. lactiflora development inflorescence stems were measured and observed. The results showed that the mechanical strength of inflorescence stems gradually increased, and that the diameter of inflorescence stem was a direct indicator in estimating mechanical strength. Simultaneously, with the development of inflorescence stem, the number of vascular bundles increased, the vascular bundle was arranged more densely, the sclerenchyma cell wall thickened, and the proportion of vascular bundle and pith also increased. On this basis, cellulose and lignin contents were determined, PlCesA3, PlCesA6 and PlCCoAOMT were isolated and their expression patterns were examined including PlPAL. The results showed that cellulose was not strictly correlated with the mechanical strength of inflorescence stem, and lignin had a significant impact on it. In addition, PlCesA3 and PlCesA6 were not key members in cellulose synthesis of P. lactiflora and their functions were also different, but PlPAL and PlCCoAOMT regulated the lignin synthesis of P. lactiflora. These data indicated that PlPAL and PlCCoAOMT could be applied to improve the mechanical strength of P. lactiflora inflorescence stem in genetic engineering.

  10. Effects of warming on chlorophyll degradation and carbohydrate accumulation of Alpine herbaceous species during plant senescence on the Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Changguang Shi

    Full Text Available Plant senescence is a critical life history process accompanied by chlorophyll degradation and has large implications for nutrient resorption and carbohydrate storage. Although photoperiod governs much of seasonal leaf senescence in many plant species, temperature has also been shown to modulate this process. Therefore, we hypothesized that climate warming would significantly impact the length of the plant growing season and ultimate productivity. To test this assumption, we measured the effects of simulated autumn climate warming paradigms on four native herbaceous species that represent distinct life forms of alpine meadow plants on the Tibetan Plateau. Conditions were simulated in open-top chambers (OTCs and the effects on the degradation of chlorophyll, nitrogen (N concentration in leaves and culms, total non-structural carbohydrate (TNC in roots, growth and phenology were assessed during one year following treatment. The results showed that climate warming in autumn changed the senescence process only for perennials by slowing chlorophyll degradation at the beginning of senescence and accelerating it in the following phases. Warming also increased root TNC storage as a result of higher N concentrations retained in leaves; however, this effect was species dependent and did not alter the growing and flowering phenology in the following seasons. Our results indicated that autumn warming increases carbohydrate accumulation, not only by enhancing activities of photosynthetic enzymes (a mechanism proposed in previous studies, but also by affecting chlorophyll degradation and preferential allocation of resources to different plant compartments. The different responses to warming can be explained by inherently different growth and phenology patterns observed among the studied species. The results implied that warming leads to changes in the competitive balance among life forms, an effect that can subsequently shift vegetation distribution and

  11. Partitioning net ecosystem carbon exchange into net assimilation and respiration using 13CO2 measurements: A cost-effective sampling strategy

    Science.gov (United States)

    OgéE, J.; Peylin, P.; Ciais, P.; Bariac, T.; Brunet, Y.; Berbigier, P.; Roche, C.; Richard, P.; Bardoux, G.; Bonnefond, J.-M.

    2003-06-01

    The current emphasis on global climate studies has led the scientific community to set up a number of sites for measuring the long-term biosphere-atmosphere net CO2 exchange (net ecosystem exchange, NEE). Partitioning this flux into its elementary components, net assimilation (FA), and respiration (FR), remains necessary in order to get a better understanding of biosphere functioning and design better surface exchange models. Noting that FR and FA have different isotopic signatures, we evaluate the potential of isotopic 13CO2 measurements in the air (combined with CO2 flux and concentration measurements) to partition NEE into FR and FA on a routine basis. The study is conducted at a temperate coniferous forest where intensive isotopic measurements in air, soil, and biomass were performed in summer 1997. The multilayer soil-vegetation-atmosphere transfer model MuSICA is adapted to compute 13CO2 flux and concentration profiles. Using MuSICA as a "perfect" simulator and taking advantage of the very dense spatiotemporal resolution of the isotopic data set (341 flasks over a 24-hour period) enable us to test each hypothesis and estimate the performance of the method. The partitioning works better in midafternoon when isotopic disequilibrium is strong. With only 15 flasks, i.e., two 13CO2 nighttime profiles (to estimate the isotopic signature of FR) and five daytime measurements (to perform the partitioning) we get mean daily estimates of FR and FA that agree with the model within 15-20%. However, knowledge of the mesophyll conductance seems crucial and may be a limitation to the method.

  12. Analyzing, Modelling, and Designing Software Ecosystems

    DEFF Research Database (Denmark)

    Manikas, Konstantinos

    of software ecosystems. We use these contributions to design a software ecosystem in the telemedicine services of Denmark with (i) a common platform that supports and promotes development from different actors, (ii) high software interaction, (iii) strong social network of actors, (iv) robust business...... as the software development and distribution by a set of actors dependent on each other and the ecosystem. We commence on the hypothesis that the establishment of a software ecosystem on the telemedicine services of Denmark would address these issues and investigate how a software ecosystem can foster...... the development, implementation, and use of telemedicine services. We initially expand the theory of software ecosystems by contributing to the definition and understanding of software ecosystems, providing means of analyzing existing and designing new ecosystems, and defining and measuring the qualities...

  13. A case study of eddy covariance flux of N2O measured within forest ecosystems: quality control and flux error analysis

    Directory of Open Access Journals (Sweden)

    T. Markkanen

    2010-02-01

    Full Text Available Eddy covariance (EC flux measurements of nitrous oxide (N2O obtained by using a 3-D sonic anemometer and a tunable diode laser gas analyzer for N2O were investigated. Two datasets (Sorø, Denmark and Kalevansuo, Finland from different measurement campaigns including sub-canopy flux measurements of energy and carbon dioxide are discussed with a focus on selected quality control aspects and flux error analysis. Although fast response trace gas analyzers based on spectroscopic techniques are increasingly used in ecosystem research, their suitability for reliable estimates of EC fluxes is still limited, and some assumptions have to be made for filtering and processing data. The N2O concentration signal was frequently dominated by offset drifts (fringe effect, which can give an artificial extra contribution to the fluxes when the resulting concentration fluctuations are correlated with the fluctuations of the vertical wind velocity. Based on Allan variance analysis of the N2O signal, we found that a recursive running mean filter with a time constant equal to 50 s was suitable to damp the influence of the periodic drift. Although the net N2O fluxes over the whole campaign periods were quite small at both sites (~5 μg N m−2 h−1 for Kalevansuo and ~10 μg N m−2 h−1 for Sorø, the calculated sub-canopy EC fluxes were in good agreement with those estimated by automatic soil chambers. However, EC N2O flux measurements show larger random uncertainty than the sensible heat fluxes, and classification according to statistical significance of single flux values indicates that downward N2O fluxes have larger random error.

  14. Estimating Spatially Heterogeneous Contributions to Ecosystem Scale Fluxes Directly From Eddy Covariance Measurements: A Case Study in Siberian wet Polygonal Tundra on Samoylov Island, Lena River Delta

    Science.gov (United States)

    Sachs, T.; Eugster, W.

    2008-12-01

    The eddy covariance method is used widely to measure the turbulent exchange fluxes of climate relevant gases such as carbon dioxide and methane. One important assumption in eddy covariance theory is homogeneity of the surface over which measurements are conducted. However, in reality the method is often applied in very heterogeneous areas and the effect of that heterogeneity on the measurement time series is not fully agreed on in the scientific community. Since the eddy covariance method relies on the time-for- space substitution concept (Taylor's frozen turbulence field assumption), spatial disturbance of the assumed homogeneity should leave similar traces in the time series data that could be detected with state-of-the-art times series statistics approaches, primarily frequency analysis. This should be easiest to detect where the observed heterogeneity is characterized by the steepest possible small-scale spatial contrast of fluxes while also exhibiting certain regularity. Thus, polygonal tundra with its regular micro-relief of very wet polygon depressions with high rates of photosynthesis and methane emission on the one hand and relatively "dry" elevated polygon rims with lower rates of photosynthesis, higher rates of respiration, and extremely low methane emissions on the other hand is considered well-suited to explore the performance of this technique of flux footprint separation. We present a case study using eddy covariance data of water vapour, carbon dioxide and methane from the Lena River Delta, Siberia, and high-resolution aerial photography to demonstrate that spatial heterogeneity correlates with deviations in eddy covariance co-spectra from the idealized co-spectra. This new method - if successful beyond a single case study - could become widely used wherever fluxes are measured over spatially heterogeneous surfaces. It would be especially helpful to move towards more accurate upscaling in areas where emission rates and processes vary greatly on

  15. Field Micrometeorological Measurements, Process-Level Studies and Modeling of Methane and Carbon Dioxide Fluxes in a Boreal Wetland Ecosystem

    Science.gov (United States)

    Verma, S. B.; Arkebauer, T. J.; Ullman, F. G.; Valentine, D. W.; Parton, W. J.; Schimel, D. S.

    1998-01-01

    The main instrumentation platform consisted of eddy correlation sensors mounted on a scaffold tower at a height of 4.2 m above the peat surface. The sensors were attached to a boom assembly which could be rotated into the prevailing winds. The boom assembly was mounted on a movable sled which, when extended, allowed sensors to be up to 2 m away from the scaffolding structure to minimize flow distortion. When retracted, the sensors could easily be installed, serviced or rotated. An electronic level with linear actuators allowed the sensors to be remotely levelled once the sled was extended. Two instrument arrays were installed. A primary (fast-response) array consisted of a three-dimensional sonic anemometer, a methane sensor (tunable diode laser spectrometer), a carbon dioxide/water vapor sensor, a fine wire thermocouple and a backup one-dimensional sonic anemometer. The secondary array consisted of a one-dimensional sonic anemometer, a fine wire thermocouple and a Krypton hygrometer. Descriptions of these sensors may be found in other reports (e.g., Verma; Suyker and Verma). Slow-response sensors provided supporting measurements including mean air temperature and humidity, mean horizontal windspeed and direction, incoming and reflected solar radiation, net radiation, incoming and reflected photosynthetically active radiation (PAR), soil heat flux, peat temperature, water-table elevation and precipitation. A data acquisition system (consisting of an IBM compatible microcomputer, amplifiers and a 16 bit analog-to-digital converter), housed in a small trailer, was used to record the fast response signals. These signals were low-pass filtered (using 8-pole Butterworth active filters with a 12.5 Hz cutoff frequency) and sampled at 25 Hz. Slow-response signals were sampled every 5 s using a network of CR21X (Campbell Scientific, Inc., Logan Utah) data loggers installed in the fen. All signals were averaged over 30-minute periods (runs).

  16. Producing fractional rangeland component predictions in a sagebrush ecosystem, a Wyoming sensitivity analysis

    Science.gov (United States)

    Xian, George; Homer, Collin G.; Granneman, Brian; Meyer, Debra K.

    2012-01-01

    Remote sensing information has been widely used to monitor vegetation condition and variations in a variety of ecosystems, including shrublands. Careful application of remotely sensed imagery can provide additional spatially explicit, continuous, and extensive data on the composition and condition of shrubland ecosystems. Historically, the most widely available remote sensing information has been collected by Landsat, which has offered large spatial coverage and moderate spatial resolution data globally for nearly three decades. Such medium-resolution satellite remote sensing information can quantify the distribution and variation of terrestrial ecosystems. Landsat imagery has been frequently used with other high-resolution remote sensing data to classify sagebrush components and quantify their spatial distributions (Ramsey and others, 2004; Seefeldt and Booth, 2004; Stow and others, 2008; Underwood and others, 2007). Modeling algorithms have been developed to use field measurements and satellite remote sensing data to quantify the extent and evaluate the quality of shrub ecosystem components in large geographic areas (Homer and others, 2009). The percent cover of sagebrush ecosystem components, including bare-ground, herbaceous, litter, sagebrush, and shrub, have been quantified for entire western states (Homer and others, 2012). Furthermore, research has demonstrated the use of current measurements with historical archives of Landsat imagery to quantify the variations of these components for the last two decades (Xian and others, 2012). The modeling method used to quantify the extent and spatial distribution of sagebrush components over a large area also has required considerable amounts of training data to meet targeted accuracy requirements. These training data have maintained product accuracy by ensuring that they are derived from good quality field measurements collected during appropriate ecosystem phenology and subsequently maximized by extrapolation on

  17. Microbial Ecosystems, Protection of

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Nelson, K.E.

    2014-01-01

    Synonyms Conservation of microbial diversity and ecosystem functions provided by microbes; Preservation of microbial diversity and ecosystem functions provided by microbes Definition The use, management, and conservation of ecosystems in order to preserve microbial diversity and functioning.

  18. Net Ecosystem Carbon Flux

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Net Ecosystem Carbon Flux is defined as the year-over-year change in Total Ecosystem Carbon Stock, or the net rate of carbon exchange between an ecosystem and the...

  19. Microbial Ecosystems, Protection of

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Nelson, K.E.

    2014-01-01

    Synonyms Conservation of microbial diversity and ecosystem functions provided by microbes; Preservation of microbial diversity and ecosystem functions provided by microbes Definition The use, management, and conservation of ecosystems in order to preserve microbial diversity and functioning. Introdu

  20. Evaluating the agreement between measurements and models of net ecosystem exchange at different times and time scales using wavelet coherence: an example using data from the North American Carbon Program Site-Level Interim Synthesis

    Directory of Open Access Journals (Sweden)

    P. C. Stoy

    2013-02-01

    Full Text Available Earth system processes exhibit complex patterns across time, as do the models that seek to replicate these processes. Model output may or may not be significantly related to observations at different times and on different frequencies. Conventional model diagnostics provide an aggregate view of model-data agreement, but usually do not identify the time and frequency patterns of model misfit, leaving unclear the steps required to improve model response to environmental drivers that vary on characteristic frequencies. Wavelet coherence can quantify the times and frequencies at which models and measurements are significantly different. We applied wavelet coherence to interpret the predictions of twenty ecosystem models from the North American Carbon Program (NACP Site-Level Interim Synthesis when confronted with eddy covariance-measured net ecosystem exchange (NEE from ten ecosystems with multiple years of available data. Models were grouped into classes with similar approaches for incorporating phenology, the calculation of NEE, and the inclusion of foliar nitrogen (N. Models with prescribed, rather than prognostic, phenology often fit NEE observations better on annual to interannual time scales in grassland, wetland and agricultural ecosystems. Models that calculate NEE as net primary productivity (NPP minus heterotrophic respiration (HR rather than gross ecosystem productivity (GPP minus ecosystem respiration (ER fit better on annual time scales in grassland and wetland ecosystems, but models that calculate NEE as GPP – ER were superior on monthly to seasonal time scales in two coniferous forests. Models that incorporated foliar nitrogen (N data were successful at capturing NEE variability on interannual (multiple year time scales at Howland Forest, Maine. Combined with previous findings, our results suggest that the mechanisms driving daily and annual NEE variability tend to be correctly simulated, but the magnitude of these fluxes is often

  1. Astronomical Ecosystems

    Science.gov (United States)

    Neuenschwander, D. E.; Finkenbinder, L. R.

    2004-05-01

    Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

  2. Elemental characterization of particulate matter emitted from biomass burning: Wind tunnel derived source profiles for herbaceous and wood fuels

    Science.gov (United States)

    Turn, S. Q.; Jenkins, B. M.; Chow, J. C.; Pritchett, L. C.; Campbell, D.; Cahill, T.; Whalen, S. A.

    1997-02-01

    Particulate matter emitted from wind tunnel simulations of biomass burning for five herbaceous crop residues (rice, wheat and barley straws, corn stover, and sugar cane trash) and four wood fuels (walnut and almond prunings and ponderosa pine and Douglas fir slash) was collected and analyzed for major elements and water soluble species. Primary constituents of the particulate matter were C, K, Cl, and S. Carbon accounted for roughly 50% of the herbaceous fuel PM and about 70% for the wood fuels. For the herbaceous fuels, particulate matter from rice straw in the size range below 10 μm aerodynamic diameter (PM10) had the highest concentrations of both K (24%) and Cl, (17%) and barley straw PM10 contained the highest sulfur content (4%). K, Cl, and S were present in the PM of the wood fuels at reduced levels with maximum concentrations of 6.5% (almond prunings), 3% (walnut prunings), and 2% (almond prunings), respectively. Analysis of water soluble species indicated that ionic forms of K, Cl, and S made up the majority of these elements from all fuels. Element balances showed K, Cl, S, and N to have the highest recovery factors (fraction of fuel element found in the particulate matter) in the PM of the elements analyzed. In general, chlorine was the most efficiently recovered element for the herbaceous fuels (10 to 35%), whereas sulfur recovery was greatest for the wood fuels (25 to 45%). Unique potassium to elemental carbon ratios of 0.20 and 0.95 were computed for particulate matter (PM10 K/C(e)) from herbaceous and wood fuels, respectively. Similarly, in the size class below 2.5 μm, high-temperature elemental carbon to bromine (PM2.5 C(eht)/Br) ratios of ˜7.5, 43, and 150 were found for the herbaceous fuels, orchard prunings, and forest slash, respectively. The molar ratios of particulate phase bromine to gas phase CO2 (PM10 Br/CO2) are of the same order of magnitude as gas phase CH3Br/CO2 reported by others.

  3. Failure of correct evapotranspiration measurements by eddy covariance under certain conditions and energy balance closure in open-oak savanna ecosystems

    Science.gov (United States)

    Pérez-Priego, Oscar; Migliavacca, Mirco; El-Madany, Tarek; Carrara, Arnaud; Moreno, Gerardo; Kolle, Olaf; Reichstein, Markus

    2016-04-01

    Separation of evapotranspiration (ET) into its components represents one of the main ecohydrological challenges in heterogeneous ecosystems (i.e. tree-grass savanna), where two main evaporative layers consisting of tree canopy (ETabove) and its underlying surface (ETsubcanopy) dominate ET. The challenge arises from the fact that classical eddy covariance 1) directly only measures total ET and 2) biases in the respective energy balance are often observed. Here, we address these challenges in a Mediterranean savannah tree-grass ecosystem, by synchronous, combined measurements via classical eddy covariance, sub-canopy eddy covariance, sap-flow, and replicated lysimeters. To this end, half-hourly latent heat fluxes of the grass layer estimated using six novel lower boundary-tension and -temperature controlled lysimeters (LEsubcanopy-lysimeter)were compared to those measured by a sub-canopy eddy covariance tower placed at 1.8 m (LEsubcanopy-eddy) over a year. To explain the residuals (epsilon) between LEsubcanopy-lysimeter and LEsubcanopy-eddy , we trained a random forest model (RF) using soil moisture (SM), ground-heat fluxes (G), net radiation (Rn), air relative humidity (RH) and friction velocity (u*) as main predictor variables. The degree of energy closure was evaluated by comparing residual LE (LEresidual, estimated as Rn-H-G; H denotes sensible heat flux) against total LE measured by a tall tower installed above the canopy at 15 m (LEeddy). In parallel, we contrasted this using independent, upscaled LE (LEupscaled= LEsubcanopy-lysimeter + LEabove-sapflow; being LEabove-sapflow the tree component derived from sap-flow measurements) to test whether failures in LEeddy explain the lack of energy balance closure. In such a case, we test the use of RF as a generalized approach to estimate epsilon and correct for LEeddy (LEeddy-corrected = LEeddy + epsilon). As main results, the comparison of independent LEsubcanopy-eddy and LEsubcanopy-lysimeter evidenced that eddy

  4. Evaluation of herbaceous crops irrigated with treated wastewater for ethanol production

    Directory of Open Access Journals (Sweden)

    Salvatore Barbagallo

    2013-09-01

    Full Text Available The competition for freshwater between agricultural, industrial, and civil uses has greatly increased in Mediterranean basin characterized by prolonged dry seasons. The aim of this study was to evaluate biomass production and the potential ethanol production of promising “no-food” herbaceous crops irrigated with low quality water at different ETc restitutions (0%, 50 and 100%. The research was carried out, in 2011 and 2012, in an open field near the full-scale constructed wetland (CW municipal treatment plant located in the Eastern Sicily (Italy. The CW effluent has been applied in a experimental irrigation field of Vetiveria zizanoides (L. Nash, Miscanthus x giganteus Greef et Deu. and Arundo donax (L.. Physical, chemical and microbiological analyses were carried out on wastewater samples collected at inlet and outlet of CW and pollutant removal efficiencies were calculated for each parameter. Bio-agronomical analysis on herbaceous species were made with the goal to evaluate the main parameters such as the plant dimension, the growth response and the biomass production. Biomass dry samples were processed with a three-step chemical pretreatment, hydrolysed with a mix of commercial enzymes and next fermented to obtain the yield of ethanol production. Average TSS, COD and TN removal for CW were about 74%, 67% and 68%, respectively. Although the satisfactory Escherichia coli removal, about 3.5 log unit for both beds on average, CW didn’t achieve the restrictive Italian law limits for wastewater reuse. As expected, irrigation was beneficial and the full ET replenishment increase the biomass productivity as compared to the other two treatment. The mean productivity of Vetiveria zizanoides and Myscanthus x giganteus were about 9, 26 and 38 t ha–1 and 3, 7 and 12 t ha–1 respectively in 0%, 50% and 100% ETc restitutions. Arundo donax gave higher values of dry biomass (78 t ha–1 in 100% ETc restitution in 2011 season, and potential ethanol

  5. Assessment of restoration measures efficiency for soil contamination in Mediterranean Ecosystem. The case study of Guadiamar Green Corridor in the context of RECARE project

    Science.gov (United States)

    Anaya-Romero, Maria; José Blanco-Velázquez, Francisco; Muñoz-Vallés, Sara

    2017-04-01

    Restoration of soil ecosystems contaminated by heavy metals requires their characterization and the assessment of measures for risk reduction. Particular soil traits and history define different levels of resilience, so soil contamination assessment needs to take into account a site-by-site approach, which considers both the particular environmental characteristics of soils and the human activities. Nevertheless, current approaches for soil contamination assessment developed as academy and market solutions continue to be rather qualitative, and they do not allow as far the selection of efficient remediation measures to solve soil contamination at the long-term and extensively over larger áreas. In this context, under the framework of RECARE (Preventing and Remediating degradation of Soils in Europe through Land Care) project, we are designing a Decision Support System (DSS) which automatically assess soil contamination values by heavy metals in the topsoil and evaluate the efficiency of soil remediation measures under scenarios of climate and land-use change. The DSS works by simulating the spatio-temporal efficiency of three widely applied remediation measures (compost, sugar beet lime and iron-rich clayey materials). Input variables are divided into: (I) climate variables (mainly precipitation and temperature), (II) site variables (elevation, slope and erodibility), (III) soil (heavy metal content, pH, sand/clay content, soil organic carbon and bulk density), (IV) land use and (V) remediation measures. The predictor variables are related to soil functions expressed by % of change of heavy metal content (Currently the DSS consider cadmium dynamics due to the worldwide distribution in agricultural system and toxicity impact on health and plants), soil carbon and erosion dynamics. The pilot study area is the Guadiamar valley (SW Spain) where the main threat is soil contamination, after a mine spill occurred on April 1998. Since that time, a huge soil databse of

  6. Impacts of solar ultraviolet-B radiation on terrestrial ecosystems of Tierra del Fuego (southern Argentina). An overview of recent progress.

    Science.gov (United States)

    Ballaré, C L; Rousseau, M C; Searles, P S; Zaller, J G; Giordano, C V; Robson, T M; Caldwell, M M; Sala, O E; Scopel, A L

    2001-09-01

    The southern part of Tierra del Fuego, in the southernmost tip of South America, is covered by dense Nothofagus spp. forests and Sphagnum-dominated peat bogs, which are subjected to the influence of ozone depletion and to increased levels of solar ultraviolet-B radiation (UV-B). Over the last 5 years we have studied some of the biological impacts of solar UV-B on natural ecosystems of this region. We have addressed two general problems: (i) do the fluctuations in UV-B levels under the influence of the Antarctic ozone 'hole' have any measurable biological impact, and (ii) what are the long-term effects of solar (ambient) UV-B on the Tierra del Fuego ecosystems? In this paper, we provide an overview of the progress made during the first 4 years of the project. We highlight and discuss the following results: (1) ambient UV-B has subtle but significant inhibitory effects on the growth of herbaceous and graminoid species of this region (growth reduction Fuego.

  7. Global Terrestrial Ecosystem Observations: Why, Where, What and How?

    NARCIS (Netherlands)

    Jongman, R.H.G.; Skidmore, A.K.; Mücher, C.A.; Bunce, R.G.H.; Metzger, M.

    2017-01-01

    This chapter covers the questions of ecosystem definition and the organisation of a monitoring system. It treats where and how ecosystems should be measured and the integration between in situ and RS observations. Ecosystems are characterised by composition, function and structure. The ecosystem

  8. The Oncor Geodatabase for the Columbia Estuary Ecosystem Restoration Program: Handbook of Data Reduction Procedures, Workbooks, and Exchange Templates

    Energy Technology Data Exchange (ETDEWEB)

    Sather, Nichole K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Borde, Amy B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Diefenderfer, Heida L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Serkowski, John A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Coleman, Andre M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Gary E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-12-01

    This Handbook of Data Reduction Procedures, Workbooks, and Exchange Templates is designed to support the Oncor geodatabase for the Columbia Estuary Ecosystem Restoration Program (CEERP). The following data categories are covered: water-surface elevation and temperature, sediment accretion rate, photo points, herbaceous wetland vegetation cover, tree plots and site summaries, fish catch and density, fish size, fish diet, fish prey, and Chinook salmon genetic stock identification. The handbook is intended for use by scientists collecting monitoring and research data for the CEERP. The ultimate goal of Oncor is to provide quality, easily accessible, geospatial data for synthesis and evaluation of the collective performance of CEERP ecosystem restoration actions at a program scale.

  9. Effect of Calcium Sprays on Mechanical Strength and Cell Wall Fractions of Herbaceous Peony (Paeonia Lactiflora Pall. Inflorescence Stems

    Directory of Open Access Journals (Sweden)

    Jintao Ge

    2012-04-01

    Full Text Available Calcium is an essential element and imparts significant structural rigidity to the plant cell walls, which provide the main mechanical support to the entire plant. In order to increase the mechanical strength of the inflorescence stems of herbaceous peony, the stems are treated with calcium chloride. The results shows that preharvest sprays with 4% (w/v calcium chloride three times after bud emergence are the best at strengthening “Da Fugui” peonies’ stems. Calcium sprays increased the concentrations of endogenous calcium, total pectin content as well as cell wall fractions in herbaceous peonies stems, and significantly increased the contents of them in the top segment. Correlation analysis showed that the breaking force of the top segment of peonies’ stems was positively correlated with the ratio of water insoluble pectin to water soluble pectin (R = 0.673 as well as lignin contents (R = 0.926 after calcium applications.

  10. Quantitative Proteomics Analysis of Herbaceous Peony in Response to Paclobutrazol Inhibition of Lateral Branching

    Directory of Open Access Journals (Sweden)

    Daqiu Zhao

    2015-10-01

    Full Text Available Herbaceous peony (Paeonia lactiflora Pall. is an emerging high-grade cut flower worldwide, which is usually used in wedding bouquets and known as the “wedding flower”. However, abundant lateral branches appear frequently in some excellent cultivars, and a lack of a method to remove Paeonia lactiflora lateral branches other than inefficient artificial methods is an obstacle for improving the quality of its cut flowers. In this study, paclobutrazol (PBZ application was found to inhibit the growth of lateral branches in Paeonia lactiflora for the first time, including 96.82% decreased lateral bud number per branch, 77.79% and 42.31% decreased length and diameter of lateral branches, respectively, declined cell wall materials and changed microstructures. Subsequently, isobaric tag for relative and absolute quantitation (iTRAQ technology was used for quantitative proteomics analysis of lateral branches under PBZ application and control. The results indicated that 178 differentially expressed proteins (DEPs successfully obtained, 98 DEPs were up-regulated and 80 DEPs were down-regulated. Thereafter, 34 candidate DEPs associated with the inhibited growth of lateral branches were screened according to their function and classification. These PBZ-stress responsive candidate DEPs were involved in eight biological processes, which played a very important role in the growth and development of lateral branches together with the response to PBZ stress. These results provide a better understanding of the molecular theoretical basis for removing Paeonia lactiflora lateral branches using PBZ application.

  11. Analysis of Codon Usage Patterns in Herbaceous Peony (Paeonia lactiflora Pall. Based on Transcriptome Data

    Directory of Open Access Journals (Sweden)

    Yanqing Wu

    2015-10-01

    Full Text Available Codon usage bias, which exists in many genomes, is mainly determined by mutation and selection. To elucidate the genetic features and evolutionary history of herbaceous peony (Paeonia lactiflora, a well-known symbol of prosperity in China, we examined synonymous codon usage in 24,216 reconstructed genes from the P. lactiflora transcriptome. The mean GC content was 44.4%, indicating that the nucleotide content of P. lactiflora genes is slightly AT rich and GC poor. The P. lactiflora genome has a wide range of GC3 (GC content at the third synonymous codon position distribution, with a significant correlation between GC12 and GC3. ENC (effective number of codons analysis suggested that mutational bias played a major role in shaping codon usage. Parity Rule 2 (PR2 analysis revealed that GC and AU were not used proportionally. We identified 22 “optimal codons”, most ending with an A or U. Our results suggested that nucleotide composition mutation bias and translational selection were the main driving factors of codon usage bias in P. lactiflora. These results lay the foundation for exploring the evolutionary mechanisms and heterologous expression of functionally-important proteins in P. lactiflora.

  12. Early vs. asymptotic growth responses of herbaceous plants to elevated CO[sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.C.; Jasienski, M.; Bazzaz, F.A. (Harvard Univ., Cambridge, MA (United States). Dept. of Organismic and Evolutionary Biology)

    1999-07-01

    Although many studies have examined the effects of elevated carbon dioxide on plant growth,'' the dynamics of growth involve at least two parameters, namely, an early rate of exponential size increase and an asymptotic size reached late in plant ontogeny. The common practice of quantifying CO[sub 2] responses as a single response ratio thus obscures two qualitatively distinct kinds of effects. The present experiment examines effects of elevated CO[sub 2] on both early and asymptotic growth parameters in eight C[sub 3] herbaceous plant species (Abutilon theophrasti, Cassia obtusifolia, Plantago major, Rumex crispus, Taraxacum officinale, Dactylis glomerata, Lolium multiflorum, and Panicum dichotomoflorum). Plants were grown for 118--172 d in a factorial design of CO[sub 2] (350 and 700 [micro]L/L) and plant density (individually grown vs. high-density monocultures) under edaphic conditions approximating those of coastal areas in Massachusetts. For Abutilon theophrasti, intraspecific patterns of plant response were also assessed using eight genotypes randomly sampled from a natural population and propagated as inbred lines.

  13. Rooting of herbaceous minicuttings of peach rootstock under effect of indolebutyric acid (IBA

    Directory of Open Access Journals (Sweden)

    Cari Rejane Fiss Timm

    2015-02-01

    Full Text Available The use of rootstocks resulting from sexual propagation is a major problem that peach crop has in Brazil, reflecting the lack of plant homogeneity, which compromises the productivity of orchards. The clonal propagation is a promising alternative for the production of homogeneous seedlings with low cost and speed, as well as the maintenance of important agronomic characteristics. Therefore, the study aimed to assess the feasibility of propagation of rootstocks of Nemared, Flordaguard and Okinawa peach cultivars through herbaceous minicuttings, testing different concentrations of IBA (0; 1,000; 2,000; and 3,000mg.L-1. The minicuttings were immersed in the solution for five seconds and, then, placed in clear plastic containers containing medium grained vermiculite. The experiment was conducted with four replications of 20 minicuttings in the greenhouse. In 45 days, it was observed that Nemared obtained 76% of rooting with 1,000 mg.L-1of IBA, not differing from Flordaguard with 66%. The estimated dose of IBA for maximum rooting was 1,590 mg.L-1.

  14. Lower Miocene plant assemblage with coastal-marsh herbaceous monocots from the Vienna Basin (Slovakia)

    Science.gov (United States)

    Kvaček, Zlatko; Teodoridis, Vasilis; Kováčová, Marianna; Schlögl, Ján; Sitár, Viliam

    2014-06-01

    A new plant assemblage of Cerová-Lieskové from Lower Miocene (Karpatian) deposits in the Vienna Basin (western Slovakia) is preserved in a relatively deep, upper-slope marine environment. Depositional conditions with high sedimentation rates allowed exceptional preservation of plant remains. The plant assemblage consists of (1) conifers represented by foliage of Pinus hepios and Tetraclinis salicornioides, a seed cone of Pinus cf. ornata, and by pollen of the Cupressaceae, Pinaceae, Pinus sp. and Cathaya sp., and (2) angiosperms represented by Cinnamomum polymorphum, Platanus neptuni, Potamogeton sp. and lauroid foliage, by pollen of Liquidambar sp., Engelhardia sp. and Craigia sp., and in particular by infructescences (so far interpreted as belonging to cereal ears). We validate genus and species assignments of the infructescences: they belong to Palaeotriticum Sitár, including P. mockii Sitár and P. carpaticum Sitár, and probably represent herbaceous monocots that inhabited coastal marshes, similar to the living grass Spartina. Similar infructescences occur in the Lower and Middle Miocene deposits of the Carpathian Foredeep (Slup in Moravia), Tunjice Hills (Žale in Slovenia), and probably also in the Swiss Molasse (Lausanne). This plant assemblage demonstrates that the paleovegetation was represented by evergreen woodland with pines and grasses in undergrowth, similar to vegetation inhabiting coastal brackish marshes today. It also indicates subtropical climatic conditions in the Vienna Basin (central Paratethys), similar to those implied by other coeval plant assemblages from Central Europe

  15. Highly acylated (acetylated and/or p-coumaroylated) native lignins from diverse herbaceous plants.

    Science.gov (United States)

    del Río, José C; Rencoret, Jorge; Marques, Gisela; Gutiérrez, Ana; Ibarra, David; Santos, J Ignacio; Jiménez-Barbero, Jesús; Zhang, Liming; Martínez, Angel T

    2008-10-22

    The structure of lignins isolated from the herbaceous plants sisal ( Agave sisalana), kenaf ( Hibiscus cannabinus), abaca ( Musa textilis) and curaua ( Ananas erectifolius) has been studied upon spectroscopic (2D-NMR) and chemical degradative (derivatization followed by reductive cleavage) methods. The analyses demonstrate that the structure of the lignins from these plants is highly remarkable, being extensively acylated at the gamma-carbon of the lignin side chain (up to 80% acylation) with acetate and/or p-coumarate groups and preferentially over syringyl units. Whereas the lignins from sisal and kenaf are gamma-acylated exclusively with acetate groups, the lignins from abaca and curaua are esterified with acetate and p-coumarate groups. The structures of all these highly acylated lignins are characterized by a very high syringyl/guaiacyl ratio, a large predominance of beta- O-4' linkages (up to 94% of all linkages), and a strikingly low proportion of traditional beta-beta' linkages, which indeed are completely absent in the lignins from abaca and curaua. The occurrence of beta-beta' homocoupling and cross-coupling products of sinapyl acetate in the lignins from sisal and kenaf indicates that sinapyl alcohol is acetylated at the monomer stage and that, therefore, sinapyl acetate should be considered as a real monolignol involved in the lignification reactions.

  16. Lower Miocene plant assemblage with coastal-marsh herbaceous monocots from the Vienna Basin (Slovakia

    Directory of Open Access Journals (Sweden)

    Kvaček Zlatko

    2014-06-01

    Full Text Available A new plant assemblage of Cerová-Lieskové from Lower Miocene (Karpatian deposits in the Vienna Basin (western Slovakia is preserved in a relatively deep, upper-slope marine environment. Depositional conditions with high sedimentation rates allowed exceptional preservation of plant remains. The plant assemblage consists of (1 conifers represented by foliage of Pinus hepios and Tetraclinis salicornioides, a seed cone of Pinus cf. ornata, and by pollen of the Cupressaceae, Pinaceae, Pinus sp. and Cathaya sp., and (2 angiosperms represented by Cinnamomum polymorphum, Platanus neptuni, Potamogeton sp. and lauroid foliage, by pollen of Liquidambar sp., Engelhardia sp. and Craigia sp., and in particular by infructescences (so far interpreted as belonging to cereal ears. We validate genus and species assignments of the infructescences: they belong to Palaeotriticum Sitár, including P. mockii Sitár and P. carpaticum Sitár, and probably represent herbaceous monocots that inhabited coastal marshes, similar to the living grass Spartina. Similar infructescences occur in the Lower and Middle Miocene deposits of the Carpathian Foredeep (Slup in Moravia, Tunjice Hills (Žale in Slovenia, and probably also in the Swiss Molasse (Lausanne. This plant assemblage demonstrates that the paleovegetation was represented by evergreen woodland with pines and grasses in undergrowth, similar to vegetation inhabiting coastal brackish marshes today. It also indicates subtropical climatic conditions in the Vienna Basin (central Paratethys, similar to those implied by other coeval plant assemblages from Central Europe

  17. Interception of wet deposited atmospheric pollutants by herbaceous vegetation: Data review and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Gonze, M.-A., E-mail: marc-andre.gonze@irsn.fr; Sy, M.M.

    2016-09-15

    Better understanding and predicting interception of wet deposited pollutants by vegetation remains a key issue in risk assessment studies of atmospheric pollution. We develop different alternative models, following either empirical or semi-mechanistic descriptions, on the basis of an exhaustive dataset consisting of 440 observations obtained in controlled experiments, from 1970 to 2014, for a wide variety of herbaceous plants, radioactive substances and rainfall conditions. The predictive performances of the models and the uncertainty/variability of the parameters are evaluated under Hierarchical Bayesian modelling framework. It is demonstrated that the variability of the interception fraction is satisfactorily explained and quite accurately modelled by a process-based alternative in which absorption of ionic substances onto the foliage surfaces is determined by their electrical valence. Under this assumption, the 95% credible interval of the predicted interception fraction encompasses 81% of the observations, including situations where either plant biomass or rainfall intensity are unknown. This novel approach is a serious candidate to challenge existing empirical relationships in radiological or chemical risk assessment tools. - Highlights: • Literature data on the interception of atmospheric pollutants by herbs were reviewed • Predictive models were developed and evaluated in the Bayesian modelling framework • Sensitivity of interception to environmental conditions was satisfactorily explained • 81% of the observations were satisfactorily predicted by a semi-mechanistic model • This model challenges empirical relationships currently used in risk assessment tools.

  18. Herbaceous forage and selection patterns by ungulates across varying herbivore assemblages in a South African Savanna.

    Directory of Open Access Journals (Sweden)

    Anna Christina Treydte

    Full Text Available Herbivores generally have strong structural and compositional effects on vegetation, which in turn determines the plant forage species available. We investigated how selected large mammalian herbivore assemblages use and alter herbaceous vegetation structure and composition in a southern African savanna in and adjacent to the Kruger National Park, South Africa. We compared mixed and mono-specific herbivore assemblages of varying density and investigated similarities in vegetation patterns under wildlife and livestock herbivory. Grass species composition differed significantly, standing biomass and grass height were almost twice as high at sites of low density compared to high density mixed wildlife species. Selection of various grass species by herbivores was positively correlated with greenness, nutrient content and palatability. Nutrient-rich Urochloa mosambicensis Hack. and Panicum maximum Jacq. grasses were preferred forage species, which significantly differed in abundance across sites of varying grazing pressure. Green grasses growing beneath trees were grazed more frequently than dry grasses growing in the open. Our results indicate that grazing herbivores appear to base their grass species preferences on nutrient content cues and that a characteristic grass species abundance and herb layer structure can be matched with mammalian herbivory types.

  19. Contribution of the biological crust to the soil CO2 efflux in a Mediterranean ecosystem

    Science.gov (United States)

    Morillas, Lourdes; Bellucco, Veronica; Lo Cascio, Mauro; Marras, Serena; Spano, Donatella; Mereu, Simone

    2016-04-01

    Lately, the important role of the soil biological crust (hereafter biocrust) in Mediterranean ecosystems is emerging from a multitude of articles. It is becoming apparent that the biocrust has an important role in regulating ecosystem functions and that it interacts with the woody and herbaceous vegetation to a degree depending on the availability of water among other factors. Here we present the first results of a wider project and focus on the contribution of the biocrust to soil CO2 efflux, and on how the respiration of the biocrust responds to soil water content and temperature. A manipulative experiment was performed in a Mediterranean shrubland ecosystem in Sardinia (Italy) to assess the contribution of the bicocrust to soil CO2 efflux and to identify the main environmental drivers of the CO2 efflux in this ecosystem. For 19 months,in situ soil CO2 efflux was measured over three different surfaces: soil deprived of biocrust (hereafter Soil), biocrust (hereafter BC) and intact soil (hereafter Soil+BC). For these surfaces, three different approaches were used to investigate the dependency of CO2 efflux on soil temperature and soil water content, e.g. a simple linear regression, a multi-linear equation, and a modified version of the most common used Lloyd and Taylor model (Lloyd and Taylor, 1994). Results showed that CO2 effluxes emitted by Soil, BC and Soil+BC were differently driven by soil moisture and temperature: BC respiration was mainly controlled by soil moisture at 5 cm depth, whereas both soil temperature and water content at 20 cm depth determined Soil CO2 efflux. Soil temperature and water content at 5 cm depth drove Soil+BC respiration. We also found that biocrust can contribute substantially (up to 60%) to the total soil respiration depending on its moisture content. This contribution persists even in periods in which deeper soil layers are inactive, as small water pulses can activate lichens, mosses and cyanobacteria associated to the biocrust as

  20. N2-fixation dynamics during ecosystem recovery in longleaf pine savannas

    Science.gov (United States)

    Tierney, J. A.

    2016-12-01

    Biological nitrogen fixation (BNF) can alleviate nitrogen (N) deficiencies that inhibit ecosystem recovery. BNF may be particularly important in ecosystems recovering from land-use change and perturbations from fire, as these disturbances can exacerbate N limitation. Here, we investigated how BNF dynamics change throughout ecosystem development in restored longleaf pine savannas, and how BNF responds to fire. We conducted this study in 59 1-ha plots of longleaf pine distributed across gradients of stand age and fire frequency at two sites in the southeastern US. We determined BNF contributions by three functional groups of N2-fixers (herbaceous legumes, biological soil crusts, and asymbiotic N2-fixing bacteria) by quantifying their abundances, assessing nitrogenase activity, and scaling these estimates up to the plot-level. To determine aboveground N demands, we measured tree growth using diameter increments and allometric equations paired with tissue-specific N concentrations. We fit linear models to evaluate the effects of stand age and time since fire on BNF and N demands throughout stand development, and performed separate analyses on mature stands to determine how fire return interval affects BNF. We observed distinct temporal patterns of N2-fixation across stand development among the three groups of N2 fixers. N2-fixation by legumes and asymbiotic bacteria remained low until stands reached maturity, while N2-fixation by biological soil crusts (BSCs) was high in juvenile stands and decreased with stand age. These patterns suggest a compensatory shift in the importance of these functional groups throughout stand development such that contributions from BSCs are critical for meeting N demands when disturbances may hinder the establishment of legumes and asymbiotic bacteria. N2-fixation by BSCs and asymbiotic bacteria throughout stand development was not affected by time since fire, but legume abundance increased the year following fire, suggesting a recovery

  1. Simulation modeling of estuarine ecosystems

    Science.gov (United States)

    Johnson, R. W.

    1980-01-01

    A simulation model has been developed of Galveston Bay, Texas ecosystem. Secondary productivity measured by harvestable species (such as shrimp and fish) is evaluated in terms of man-related and controllable factors, such as quantity and quality of inlet fresh-water and pollutants. This simulation model used information from an existing physical parameters model as well as pertinent biological measurements obtained by conventional sampling techniques. Predicted results from the model compared favorably with those from comparable investigations. In addition, this paper will discuss remotely sensed and conventional measurements in the framework of prospective models that may be used to study estuarine processes and ecosystem productivity.

  2. Performance of Planted Herbaceous Species in Longleaf Pine (Pinus palustris Mill.) Plantations: Overstory Effects of Competition and Needlefall

    Energy Technology Data Exchange (ETDEWEB)

    Dagley, C.M.

    2001-07-03

    Research to determine the separate effects of above-ground and below-ground competition and needlefall of over-story pines on under-story plant performance. Periodic monitoring of over-story crown closure, soil water content, temperature, and nutrients were conducted. Results indicate competition for light had a more determental effect on performance of herbaceous species in longleaf pine plantations than that resulting from competition for below-ground resources.

  3. Heavy metal accumulation and signal transduction in herbaceous and woody plants: Paving the way for enhancing phytoremediation efficiency.

    Science.gov (United States)

    Luo, Zhi-Bin; He, Jiali; Polle, Andrea; Rennenberg, Heinz

    2016-11-01

    Heavy metal (HM)-accumulating herbaceous and woody plants are employed for phytoremediation. To develop improved strategies for enhancing phytoremediation efficiency, knowledge of the microstructural, physiological and molecular responses underlying HM-accumulation is required. Here we review the progress in understanding the structural, physiological and molecular mechanisms underlying HM uptake, transport, sequestration and detoxification, as well as the regulation of these processes by signal transduction in response to HM exposure. The significance of genetic engineering for enhancing phytoremediation efficiency is also discussed. In herbaceous plants, HMs are taken up by roots and transported into the root cells via transmembrane carriers for nutritional ions. The HMs absorbed by root cells can be further translocated to the xylem vessels and unloaded into the xylem sap, thereby reaching the aerial parts of plants. HMs can be sequestered in the cell walls, vacuoles and the Golgi apparatuses. Plant roots initially perceive HM stress and trigger the signal transduction, thereby mediating changes at the molecular, physiological, and microstructural level. Signaling molecules such as phytohormones, reactive oxygen species (ROS) and nitric oxide (NO), modulate plant responses to HMs via differentially expressed genes, activation of the antioxidative system and coordinated cross talk among different signaling molecules. A number of genes participated in HM uptake, transport, sequestration and detoxification have been functionally characterized and transformed to target plants for enhancing phytoremediation efficiency. Fast growing woody plants hold an advantage over herbaceous plants for phytoremediation in terms of accumulation of high HM-amounts in their large biomass. Presumably, woody plants accumulate HMs using similar mechanisms as herbaceous counterparts, but the processes of HM accumulation and signal transduction can be more complex in woody plants.

  4. In situ spectral measurements improve the efficiency of light use efficiency models to estimate gross primary productivity in Mediterranean cork oak woodland

    Science.gov (United States)

    Cerasoli, S.; Silva, J. M.; Carvalhais, N.; Correia, A.; Costa e Silva, F.; Pereira, J. S.

    2013-12-01

    The Light Use Efficiency (LUE) concept is usually applied to retrieve Gross Primary Productivity (GPP) estimates in models integrating spectral indexes, namely Normalized Difference Vegetation Index (NDVI) and Photochemical Reflectance Index (PRI), considered proxies of biophysical properties of vegetation. The integration of spectral measurements into LUE models can increase the robustness of GPP estimates by optimizing particular parameters of the model. NDVI and PRI are frequently obtained by broad band sensors on remote platforms at low spatial resolution (e.g. MODIS). In highly heterogeneous ecosystems such spectral information may not be representative of the dynamic response of the ecosystem to climate variables. In Mediterranean oak woodlands different plant functional types (PFT): trees canopy, shrubs and herbaceous layer, contribute to the overall Gross Primary Productivity (GPP). In situ spectral measurements can provide useful information on each PFT and its temporal variability. The objectives of this study were: i) to analyze the temporal variability of NDVI, PRI and others spectral indices for the three PFT, their response to climate variables and their relationship with biophysical properties of vegetation; ii) to optimize a LUE model integrating selected spectral indexes in which the contribution of each PFT to the overall GPP is estimated individually; iii) to compare the performance of disaggregated GPP estimates and lumped GPP estimates, evaluated against eddy covariance measurements. Ground measurements of vegetation reflectance were performed in a cork oak woodland located in Coruche, Portugal (39°8'N, 8°19'W) where carbon and water fluxes are continuously measured by eddy covariance. Between April 2011 and June 2013 reflectance measurements of the herbaceous layer, shrubs and trees canopy were acquired with a FieldSpec3 spectroradiometer (ASD Inc.) which provided data in the range of 350-2500nm. Measurements were repeated approximately on

  5. Herbaceous Production In Cut-burned, Uncut-burned, And Control Areas Of A Charnaecyparis thyoides (L.) BSP (Cupressaceae) Stand In The Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Herbaceous Production in cut-burned, uncut-burned, and control areas of a Chamaecyparis thyoides (L.) BSP (Cupressaceae) stand in the Great Dismal Swamp. The biomass...

  6. Relationship between herbaceous biomass and 1km (2) advanced very high resolution radiometer (AVHRR) NDVI in Kruger National Park, South Africa

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2006-03-01

    Full Text Available The relationship between multi-year (1989-2003), herbaceous biomass and 1-km(2) Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index (NDVI) data in Kruger National Park (KNP), South Africa is considered...

  7. INTERACTIONS BETWEEN THE HERBACEOUS AND SHRUBBY-ARBOREAL COMPONENTS IN A SEMIARID REGION IN THE NORTHEAST OF BRAZIL: COMPETITION OR FACILITATION?

    OpenAIRE

    KLEBER ANDRADE DA SILVA; JOSIENE MARIA FALCÃO FRAGA DOS SANTOS; DANIELLE MELO DOS SANTOS; JULIANA RAMOS DE ANDRADE; ELBA MARIA NOGUEIRA FERRAZ; ELCIDA DE LIMA ARAÚJO

    2015-01-01

    Under conditions of high stress, interactions between species can be positive. Islands of perennial vegetation can improve the conditions of the understory and facilitate the establishment of herbaceous plants. The hypothesis of this study is that islands of perennial vegetation in an area of caatinga harbor, a greater richness, diversity and density of herbaceous plants, and that individuals reach a greater height and diameter than in open spaces. The study was conducted in Petrolândia, Pern...

  8. Horticultural markets promote alien species invasions: an Estonian case study of herbaceous perennials

    Directory of Open Access Journals (Sweden)

    Merle Ööpik

    2013-06-01

    Full Text Available Gardening is a popular pastime, but commercial horticulture is responsible for the introduction of alien species and contributes to invasions in a variety of ways. Although an extensive international literature is available on plant invasions, it is still important at the national level to examine the influence of local factors. Accordingly, 17 nurseries in Estonia that cultivated and sold perennial alien species were selected, and a list of species and prices was compiled. The relationships between species status, and factors such as their abundance in the wild were examined statistically. A qualitative list of the nationally problematic species among herbaceous perennials was also completed. A total of 880 taxa were recorded, of which 10.3% were native and 89.7% alien. In all, 87.3% of the alien species were still confined to cultivated areas. The ecological and socio-economic characteristics of the taxa were described, and lists of the families of casual, naturalised and invasive aliens were provided. Both native and increasing wild alien species have a very similar profile on the market. Alien species that are less expensive, widely available and have more cultivars per species on the market are also more likely to escape. The invasive status and abundance of escaped aliens in an area increases with residence time. In general, socio-economic factors create new and reflect previous propagule pressures from commercial horticulture, which continuously increase the likelihood of alien species surviving and invading new areas. Our findings suggest that these national socio-economic market-related factors explain much of the invasiveness of various perennial ornamental species, and therefore regional and national authorities urgently need to regulate and control the ornamental plant trade to diminish the risk of new invasions.

  9. Hydration status influences seed fire tolerance in temperate European herbaceous species.

    Science.gov (United States)

    Ruprecht, E; Lukács, K; Domokos, P; Kuhn, T; Fenesi, A

    2016-03-01

    Prescribed burning is an important management tool in many parts of the world. While natural fires generally occur during the driest and warmest period of the year, prescribed burning is often timed out-of-season, when there is higher soil moisture and lower biomass combustibility. However, fire season may influence seedling recruitment after fire, e.g. through the effect of seed hydration status on fire tolerance. In non-fire-prone temperate regions, anthropogenic fire may occur exclusively in periods outside the growing season with higher soil moisture, which may have negative consequences on seedling recruitment. Fire tolerance of moist and dry seeds of 16 temperate European herbaceous species belonging to four families was assessed using heat treatment of 100 °C for 5 min and subsequent germination trials. Moist seeds of Asteraceae, Poaceae and Brassicaceae had a predominantly negative reaction to the heat treatment, while those of Fabaceae tolerated it or germination was even enhanced. The reaction of dry seeds was completely different, with positive responses in three species of the Fabaceae and fire tolerance in species of other families. Our results point out that hydration status may significantly influence the post-fire germination of seeds. Dry seeds were found to tolerate high heat, while moist seeds were harmed in more than half of the species. This implies that if prescribed burning is applied in temperate grasslands of Europe, it should be timed to dry periods of the dormant season in order to protect seeds from negative effects of fire.

  10. Evidence for herbaceous seed dispersal by small-bodied fishes in a Pantanal seasonal wetland.

    Science.gov (United States)

    Silveira, R M L; Weiss, B

    2014-08-01

    We analysed the germination of seeds after their passage through the digestive tract of small floodplain fishes. Samples were collected in five open flooded fields of the northern Pantanal in March 2011. All fishes were sacrificed and their intestinal contents were removed. The fecal material was weighed and stored at 4°C in a GF/C filter wrapped in aluminum foil. The material was then transferred to a receptacle containing sterilised soil from the sampling area. The fecal samples were kept in a germination chamber for 68 days and then transferred to a greenhouse for another 67 days. We collected a total of 45 fish species and 1014 individuals which produced a total amount of 32 g of fresh fecal mass and 11 seedlings. We were able to identify six seedlings: two Banara arguta, two Steinchisma laxa, one Hymenachne amplexicaulis and one Luziola sp.. The fish species that produced samples with seedlings were Astyanax assuncionensis, Metynnis mola, Plesiolebias glaucopterus, Acestrorhyncus pantaneiro and Anadoras wendelli. With the exception of B. arguta the remaining plant species and all fish species were not known to be associated with the seed dispersal process of these plants. We found a ratio of 0.435 seedlings.g-1 of fresh fecal material, which is 100 times higher than the amount of seedlings encountered in fresh soil mass (92,974 grams) in seed bank studies conducted in the same study area. In particular, Astyanax assuncionensis and Metynnis mola were among the most frequent and most abundant fish taxa in the area. Together with the high seed concentration in the fish fecal material, this evidence allows us to conclude that such fish species may play an important role in seed dispersal in the herbaceous plants of the Pantanal.

  11. Effects of sowing native herbaceous species on the post-fire recovery in a heathland

    Science.gov (United States)

    Fernández-Abascal, I.; Tárrega, R.; Luis-Calabuig, E.; Marcos, E.

    2003-07-01

    Erica australis heathlands in León province (NW Spain) have high resilience to disturbances and their post-fire recovery is very fast. The risk of soil erosion is high in the first few months after fire. The aim of this study is to investigate the effects on post-fire succession of sowing grass ( Agrostis capillaris and Festuca rubra) and legume ( Lotus corniculatus) seeds in a heathland burned by a summer wildfire, and to determine the most suitable native herbaceous species combination for protecting the soil in the first few phases of recovery. Fifteen permanent 4 m 2 plots are established in the burned area; four treatments and a control (unsown) are applied, each with three replicates. Three similar unburned plots are also considered (unburned control). Total cover is significantly higher in the sown plots in relation to the control in the first few months after sowing, but there are no differences after 18 months. Lotus corniculatus appears only in the first year and has no effect on the total cover. F. rubra appears earlier than Agrostis capillaris, but decreases significantly in cover after 18 months. Shrub species have the highest cover in the control plots and the lowest in the Agrostis plots. The correspondence analysis shows that the trend for vegetation in all plots reaches similar species composition by the time of final sampling. The last sampling of sown plots shows greater similarity to the control plots than the sampling of these plots within the first year. The fast initial growth of F. rubra, together with its decrease and subsequent low cover from the second year, make it more preferable than Agrostis capillaris for purposes of soil protection. However, additional research, both species- and site-specific, is necessary, as different responses due to different post-fire conditions and pre-fire species composition can have important implications on community dynamics.

  12. Anatomical and biochemical analysis reveal the role of anthocyanins in flower coloration of herbaceous peony.

    Science.gov (United States)

    Zhao, Da-Qiu; Wei, Meng-Ran; Liu, Ding; Tao, Jun

    2016-05-01

    Herbaceous peony (Paeonia lactiflora Pall.) is particularly appreciated because of its elegant and gorgeous flower color, but little is known about the underlying mechanisms of flower coloration. In this study, three P. lactiflora cultivars 'Xuefeng', 'Fenyulou' and 'Dahonglou' with white, pink and red flower were selected as the materials. Their anatomical structures, cell sap pH and metal elements were investigated, and the colored pigment mainly distributed in palisade mesophyll was only found in 'Fenyulou' and 'Dahonglou', and their shape of epidermal cells, cell sap pH and metal elements were not the key factors deciding phenotype color. Moreover, the qualitative and quantitative analysis of flavonoids were performed, their total anthocyanin, anthoxanthin and flavonoid contents were decreased during flower development, and only anthocyanin content in 'Dahonglou' was always higher than that in 'Xuefeng' and 'Fenyulou'. Subsequently, three anthocyanin compositions were found, and peonidin 3,5-di-O-glucoside (Pn3G5G) was identified as the main anthocyanin composition. In addition, the full-length of flavonol synthase gene (FLS) was isolated with the GenBank accession number KM259902, and the expression patterns of eight flavonoid biosynthetic genes showed that only PlDFR and PlANS basically had the highest levels in 'Dahonglou' and the lowest levels in 'Xuefeng', and they basically displayed a descended trend during flower development especially PlDFR, suggesting that these two genes might play a key role in the anthocyanin biosynthesis which resulted in the shift from white to pink and red in flowers. These results would contribute to understand the underlying molecular mechanisms of flower coloration in P. lactiflora.

  13. Herbaceous crops and trees can provide bioenergy needs in humid Lower South, USA

    Energy Technology Data Exchange (ETDEWEB)

    Prine, G.M.; Rockwood, D.L. [University of Florida, Gainesville, FL (United States)

    1999-07-01

    The Humid Lower South (HLS) can be a leading producer of bioenergy. It has adequate land area, long warm growing season, high rainfall and a subtropical climate which allows production of a number of tropical perennial grasses, the tropical tree legume leucaena, and short rotation woody trees. The vegetatively propagated tall grasses, sugarcane and energy cane (Saccarhum sp.), elephantgrass (Pennisetum purpureum) and erianthus (Erianthus arundenaceum), all have high linear growth rates of 17 to 27 g m{sup -2} d{sup -1} for 140 to 196 days or longer. Dry matter yields of 20 to 60 Mg ha{sup -1} yr{sup -1} are possible depending on crop, location, season, soils, management and climate. The seed propagated switch grass (Panicum virgatum) offers sustainable dry biomass production of 15 to 22 Mg ha{sup -1} yr{sup -1}. Tall castor bean (Ricinus communis) has produced two-year-old dry stem yield of 65 Mg ha{sup -.} Leucaena (Leucaena sp.) has an annual or multiple season woody stem production with potential dry matter annual yields of 19 to 31 Mg ha{sup -1}. Besides these herbaceous crops the vast natural forests can be supplemented by short rotation woody crops having potential yields of 15-35 dry Mg ha{sup -1} yr{sup -l}. The northern portion of HLS can grow short rotation cottonwood (Populus deltoides) and slash pine (Pinus elliottii) on many soils. Eucalyptus species can be grown in peninsular Florida. Culture of the bioenergy crops is enhanced by application of sewage sludge and waste waters. Industries can take advantage of various mixtures of these available high-biomass-yielding crops for energy use. (author)

  14. Transformation of Digital Ecosystems

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Hedman, Jonas

    2014-01-01

    In digital ecosystems, the fusion relation between business and technology means that the decision of technical compatibility of the offering is also the decision of how to position the firm relative to the coopetive relations that characterize business ecosystems. In this article we develop...... the Digital Ecosystem Technology Transformation (DETT) framework for explaining technology-based transformation of digital ecosystems by integrating theories of business and technology ecosystems. The framework depicts ecosystem transformation as distributed and emergent from micro-, meso-, and macro- level...... coopetition. The DETT framework consists an alternative to the existing explanations of digital ecosystem transformation as the rational management of one central actor balancing ecosystem tensions. We illustrate the use of the framework by a case study of transformation in the digital payment ecosystem...

  15. The Global Ecosystem Dynamics Investigation

    Science.gov (United States)

    Dubayah, R.; Goetz, S. J.; Blair, J. B.; Fatoyinbo, T. E.; Hansen, M.; Healey, S. P.; Hofton, M. A.; Hurtt, G. C.; Kellner, J.; Luthcke, S. B.; Swatantran, A.

    2014-12-01

    Spaceborne lidar has been identified as a key technology by the international ecosystem science community because it enables accurate estimates of canopy structure and biomass and forms the basis for fusion approaches that extend the capabilities of existing and planned radar missions, such as the NASA-ISRO SAR and the ESA BIOMASS mission. The Global Ecosystems Dynamics Investigation Lidar (GEDI Lidar) was recently selected by NASA's Earth Ventures Instrument (EVI) program. From its vantage point on the International Space Station, GEDI Lidar provides high-resolution observations of forest vertical structure and addresses three, core science questions: What is the aboveground carbon balance of the land surface? What role will the land surface play in mitigating atmospheric CO2 in the coming decades? How does ecosystem structure affect habitat quality and biodiversity? GEDI informs these science questions by making billions of lidar waveform observations of canopy structure over its nominal one year mission length. The instrument uses three laser transmitters to produce 14 parallel tracks of 25 m footprints. These canopy measurements are then used to measure biomass and in fusion with radar and other remote sensing data to quantify changes in biomass resulting from disturbance and recovery. GEDI further marries ecosystem structure from lidar with ecosystem modeling to predict the sequestration potential of existing forests and to evaluate the impact of policy-driven afforestation and reforestation actions on sequestering additional carbon. Lastly, GEDI's observations of ecosystem structure provide a mapping of critical habitat metrics at the fine scales required for understanding the patterns, processes, and controls on biodiversity and habitat quality. The selection of GEDI Lidar, when combined with the rapid advancement of new radar missions and the availability of long-term land cover archives from passive optical sensors, ushers in an exciting new era of land

  16. Reduced herbivory during simulated ENSO rainy events increases native herbaceous plants in semiarid Chile

    NARCIS (Netherlands)

    Manrique, R.; Gutierrez, J.R.; Holmgren, M.; Squeo, F.A.

    2007-01-01

    El Niño Southern Oscillation (ENSO) events have profound consequences for the dynamics of terrestrial ecosystems. Since increased climate variability is expected to favour the invasive success of exotic species, we conducted a field experiment to study the effects that simulated rainy ENSO events in

  17. Spatial and temporal variation in invertebrate consumer diets in forested and herbaceous wetlands

    Science.gov (United States)

    Alani N. Taylor; Darold P. Batzer

    2010-01-01

    Macroinvertebrates have important functional roles in wetland ecosystems, but these roles are not always well understood. This study assessed which foods invertebrate consumers assimilate within a set of wetland habitats. During 2006 and 2007, non-Tanypodinae chironomid larvae and select crustaceans (Crangonyx amphipods, Caecidotea isopods, Simocephalus cladocerans)...

  18. 浅析广州万亩果园草本水生植物种植技术%Analysis of Planting Technology for Herbaceous Aquatic Plant in Wan Mu Orchard in Guangzhou

    Institute of Scientific and Technical Information of China (English)

    严建辉

    2013-01-01

    随着城市湿地公园对水体景观的设计运用越来越多,草本水生植物的种植施工标准也越来越高。目前园林草本水生植物在施工上存在忽略常水位线、种植密度不合理、忽视最佳施工时间和后期养护等诸多问题,文章以广州市海珠区万亩果园湿地公园为例,针对以上问题深入探讨湿地公园中草本水生植物的种植技术措施。%With the raise using of design of urban water landscape, the planting standards in technical levels of herbaceous aquatic plants are getting higher and higher in wetland park. There are lots of problems about herbaceous aquatic plants planting, such as ignoring watermark, planting density, construction time and maintenance in garden. Wan Mu Orchard which is a wetland park in Haizhu district is taked as an example in this article and some measures are proposed according to technical problems of herbal aquatic plants cultivation technology in the Wetland Park.

  19. FWS Ecosystem Regions

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Digital ecosystem information portraying the location and boundaries of the ecosystems. The Service originally chose the U.S. Geological Survey's Hydrologic Unit Map...

  20. Coral reefs - Specialized ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.

    This paper discusses briefly some aspects that characterize and differentiate coral reef ecosystems from other tropical marine ecosystems. A brief account on the resources that are extractable from coral reefs, their susceptibility to natural...

  1. Compound-specific δ15N amino acid measurements in littoral mussels in the California upwelling ecosystem: a new approach to generating baseline δ15N Isoscapes for coastal ecosystems.

    Science.gov (United States)

    Vokhshoori, Natasha L; McCarthy, Matthew D

    2014-01-01

    We explored δ(15)N compound-specific amino acid isotope data (CSI-AA) in filter-feeding intertidal mussels (Mytilus californianus) as a new approach to construct integrated isoscapes of coastal primary production. We examined spatial δ(15)N gradients in the California Upwelling Ecosystem (CUE), determining bulk δ(15)N values of mussel tissue from 28 sites between Port Orford, Oregon and La Jolla, California, and applying CSI-AA at selected sites to decouple trophic effects from isotopic values at the base of the food web. Bulk δ(15)N values showed a strong linear trend with latitude, increasing from North to South (from ∼ 7‰ to ∼ 12‰, R(2) = 0.759). In contrast, CSI-AA trophic position estimates showed no correlation with latitude. The δ(15)N trend is therefore most consistent with a baseline δ(15)N gradient, likely due to the mixing of two source waters: low δ(15)N nitrate from the southward flowing surface California Current, and the northward transport of the California Undercurrent (CUC), with (15)N-enriched nitrate. This interpretation is strongly supported by a similar linear gradient in δ(15)N values of phenylalanine (δ(15)NPhe), the best AA proxy for baseline δ(15)N values. We hypothesize δ(15)N(Phe) values in intertidal mussels can approximate annual integrated δ(15)N values of coastal phytoplankton primary production. We therefore used δ(15)N(Phe) values to generate the first compound-specific nitrogen isoscape for the coastal Northeast Pacific, which indicates a remarkably linear gradient in coastal primary production δ(15)N values. We propose that δ(15)N(Phe) isoscapes derived from filter feeders can directly characterize baseline δ(15)N values across major biochemical provinces, with potential applications for understanding migratory and feeding patterns of top predators, monitoring effects of climate change, and study of paleo- archives.

  2. Compound-specific δ15N amino acid measurements in littoral mussels in the California upwelling ecosystem: a new approach to generating baseline δ15N Isoscapes for coastal ecosystems.

    Directory of Open Access Journals (Sweden)

    Natasha L Vokhshoori

    Full Text Available We explored δ(15N compound-specific amino acid isotope data (CSI-AA in filter-feeding intertidal mussels (Mytilus californianus as a new approach to construct integrated isoscapes of coastal primary production. We examined spatial δ(15N gradients in the California Upwelling Ecosystem (CUE, determining bulk δ(15N values of mussel tissue from 28 sites between Port Orford, Oregon and La Jolla, California, and applying CSI-AA at selected sites to decouple trophic effects from isotopic values at the base of the food web. Bulk δ(15N values showed a strong linear trend with latitude, increasing from North to South (from ∼ 7‰ to ∼ 12‰, R(2 = 0.759. In contrast, CSI-AA trophic position estimates showed no correlation with latitude. The δ(15N trend is therefore most consistent with a baseline δ(15N gradient, likely due to the mixing of two source waters: low δ(15N nitrate from the southward flowing surface California Current, and the northward transport of the California Undercurrent (CUC, with (15N-enriched nitrate. This interpretation is strongly supported by a similar linear gradient in δ(15N values of phenylalanine (δ(15NPhe, the best AA proxy for baseline δ(15N values. We hypothesize δ(15N(Phe values in intertidal mussels can approximate annual integrated δ(15N values of coastal phytoplankton primary production. We therefore used δ(15N(Phe values to generate the first compound-specific nitrogen isoscape for the coastal Northeast Pacific, which indicates a remarkably linear gradient in coastal primary production δ(15N values. We propose that δ(15N(Phe isoscapes derived from filter feeders can directly characterize baseline δ(15N values across major biochemical provinces, with potential applications for understanding migratory and feeding patterns of top predators, monitoring effects of climate change, and study of paleo- archives.

  3. The Measurement and Analysis on the Level of the Coordinated Development of Innovation Ecosystem in Tianjin%天津市创新生态系统协调发展水平测度与评价

    Institute of Scientific and Technical Information of China (English)

    胡彪; 付业腾

    2015-01-01

    This paper applies the measurement model of the degree of coordinated development to measure and evaluate the coordination degree of the innovation ecosystem in Tianjin. The evidence shows: from 2002 to 2013, the overall level of the degree of coordinated development of the innovation ecosystem in Tianjin is not high; to improve the order degree of ecological flow subsystem has become the main task for the coordinated development of innovation ecosystem in Tianjin.%运用协调发展度测量模型对天津市创新生态系统协调水平进行测度与评价。实证表明:2002-2013年天津市创新生态系统协调发展度总体水平不高,提高生态流子系统有序度成为天津市创新生态系统协调发展的重要任务。

  4. Global Ecosystem Restoration Index

    DEFF Research Database (Denmark)

    Fernandez, Miguel; Garcia, Monica; Fernandez, Nestor

    2015-01-01

    The Global ecosystem restoration index (GERI) is a composite index that integrates structural and functional aspects of the ecosystem restoration process. These elements are evaluated through a window that looks into a baseline for degraded ecosystems with the objective to assess restoration...

  5. Rights to ecosystem services

    NARCIS (Netherlands)

    Davidson, M.

    2014-01-01

    Ecosystem services are the benefits people obtain from ecosystems. Many of these services are provided outside the borders of the land where they are produced; this article investigates who is entitled to these non-excludable ecosystem services from two libertarian perspectives. Taking a

  6. Towards ecosystem accounting

    NARCIS (Netherlands)

    Duku, C.; Rathjens, H.; Zwart, S.J.; Hein, L.

    2015-01-01

    Ecosystem accounting is an emerging field that aims to provide a consistent approach to analysing environment-economy interactions. One of the specific features of ecosystem accounting is the distinction between the capacity and the flow of ecosystem services. Ecohydrological modelling to support

  7. Soil formation on reddish-brown calcareous till under herbaceous vegetation during forty years

    Directory of Open Access Journals (Sweden)

    Reintam, Loit

    2007-06-01

    Full Text Available A special experiment was established in 1963 and initiated in 1964 at Eerika, Tartu County, Estonia (58°22¢ N, 26°36¢ E to study pedogenesis and its continuous development under grass-herbaceous vegetation on reddish-brown calcareous till which was practically free from organic carbon (0.6 g kg–1 and nitrogen (0.2 g kg–1. The results of the study of three earlier decades have been discussed earlier. This paper deals with the processes of synchronous production and soil formation as well as with pedogenetic activity during the fourth decade of the experiment and during the total period of 40 years. An intensive humus-accumulative process, wavy and cyclic in intensity, has continued, accompanied by the breakdown of skeletal carbonates, partial leaching of products, formation and accumulation of amorphous and crystalline nonsiliceous products of weathering, progress of argillization in situ, and slight lessivage of fine silt and clay within the thin top of enriched humus solum. Net accumulation of organic carbon and nitrogen was obtained by nearly equivalent amounts of humifiable issues of the production process. As these are temporally dynamic, the temporal periodicity of mineralization and humification relationships is also characteristic of synchronous pedogenesis. The low C : N ratio indicates an excellent quality of the humus formed since the beginning of primary soil formation. Against the background of the decadewise dynamic fulvicity of the humus and evident decrease in its total solubility, the transformation of Ca-humates into humins and the formation of R2O3-humic-fulvic complexes at the expense of RO-humic-fulvic complexes already during the third decade were ascertained. Intensification of the bonds of the humic-fulvic complexes with inactive sesquioxides and clay minerals and decrease in the amount of fulvic acids in the interlayeral structure of clay progressed during the fourth decade. Due to the weathering of sand fractions

  8. The factors controlling species density in herbaceous plant communities: An assessment

    Science.gov (United States)

    Grace, J.B.

    1999-01-01

    This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of

  9. Reproductive allocation and output in herbaceous annuals of the genera Polygonum, Ipomoea, and Cassia in elevated CO[sub 2] environments

    Energy Technology Data Exchange (ETDEWEB)

    Farnsworth, E.J.; Bazzaz, F.A. (Harvard Univ., Cambridge, MA (United States))

    1994-06-01

    In assessing the capacity of plants to adapt to rapidly changing global climate, we must elucidate the impacts of elevated carbon dioxide on reproduction, fitness and evolution. We investigated how elevated CO[sub 2] influenced reproduction and growth of plants exhibiting a range of floral displays, the implications of shifts in allocation for fitness in these species, and whether related taxa would show similar patterns of response. Three herbaceous, annual species each of the genera Polygonum, Ipomoea, and Cassia were grown under 350 or 700 ppm CO[sub 2]. Vegetative growth and reproductive output were non-destructively measured throughout the full life span, and biomass calibrated with a subsample harvest at first flowering. Viability and germination studies of seed progeny were conducted to more precisely characterize fitness. Timecourse and numbers of floral buds, flowers, unripe and abscised fruits differed between CO[sub 2] treatments. Genera differed significantly in their phenological responses to elevated CO[sub 2], Polygonum and Cassia species (but not Ipomoea) showed accelerated, enhanced reproduction. Elevated CO[sub 2] ameliorated trade-offs between vegetative and floral production. However, seed [open quotes]quality[close quotes] and fitness were not always directly correlated with quantity produced. Species within general responded more consistently to CO[sub 2], indicating that phylogeny and life form may be general predictors of performance under global change.

  10. Effects of Ontogeny on δ13C of Plant- and Soil-Respired CO2 and on Respiratory Carbon Fractionation in C3 Herbaceous Species.

    Directory of Open Access Journals (Sweden)

    Yann Salmon

    Full Text Available Knowledge gaps regarding potential ontogeny and plant species identity effects on carbon isotope fractionation might lead to misinterpretations of carbon isotope composition (δ13C of respired CO2, a widely-used integrator of environmental conditions. In monospecific mesocosms grown under controlled conditions, the δ13C of C pools and fluxes and leaf ecophysiological parameters of seven herbaceous species belonging to three functional groups (crops, forage grasses and legumes were investigated at three ontogenetic stages of their vegetative cycle (young foliage, maximum growth rate, early senescence. Ontogeny-related changes in δ13C of leaf- and soil-respired CO2 and 13C/12C fractionation in respiration (ΔR were species-dependent and up to 7‰, a magnitude similar to that commonly measured in response to environmental factors. At plant and soil levels, changes in δ13C of respired CO2 and ΔR with ontogeny were related to changes in plant physiological status, likely through ontogeny-driven changes in the C sink to source strength ratio in the aboveground plant compartment. Our data further showed that lower ΔR values (i.e. respired CO2 relatively less depleted in 13C were observed with decreasing net assimilation. Our findings highlight the importance of accounting for ontogenetic stage and plant community composition in ecological studies using stable carbon isotopes.

  11. Stable oxygen isotope analysis reveal vegetation influence on soil water movement and ecosystem water fluxes in a semi-arid oak woodland

    Science.gov (United States)

    Piayda, Arndt; Dubbert, Maren; Werner, Christiane; Cuntz, Matthias

    2015-04-01

    Mechanistically disentangling the role and function of vegetation within the hydrological cycle is one of the key questions in the interdisciplinary field of ecohydrology. The presence of vegetation can have various impacts on soil water relations: transpiration of active vegetation causes great water losses, rainfall is intercepted, soil evaporation can be reduced and infiltration, hydraulic redistribution and translatory flow might be altered. In drylands, covering around 40% of the global land surface, the carbon cycle is closely coupled to water availability due to (seasonal) droughts. Specifically savannah type ecosystems, which cover large areas worldwide, are, due to their bi-layered structure, very suitable to study the effects of distinct vegetation types on the ecosystem water cycle. Oxygen isotope signatures (δ18O) have been used to partition ecosystem evapotranspiration (ET ) because of the distinct isotopic compositions of water transpired by leaves relative to soil evaporated vapor. Recent developments in laser spectroscopy enable measurements of δ18O in the vapor phase with high temporal resolution in the field and bear a novel opportunity to trace water movement within the ecosystem. In the present study, the effects of distinct vegetation layers (i.e. trees and herbaceous vegetation) on soil water infiltration and redistribution as well as ecosystem water fluxes in a Mediterranean cork-oak woodland are disentangled. An irrigation experiment was carried out using δ18O labeled water to quantify the distinct effects of trees and herbaceous vegetation on 1) infiltration and redistribution of water in the soil profile and 2) to disentangle the effects of tree cover on the contribution of unproductive soil evaporation and understory transpiration to total ET . First results proof that stable δ18O isotopes measured onsite with laser spectroscopy is a valuable tool to trace water movement in the soil showing a much higher sensitivity than common TDR

  12. Relating a Spectral Index from MODIS and Tower-based Measurements to Ecosystem Light Use Efficiency for a Fluxnet-Canada Coniferous Forest

    Science.gov (United States)

    Middleton, Elizabeth M.; Cheng, Yen-Ben; Hilker, Thomas; Huemmrich, Karl F.; Black, T. Andrew; Krishnan, Praveena; Coops, Nicholas C.

    2008-01-01

    As part of the North American Carbon Program effort to quantify the terrestrial carbon budget of North America, we have been examining the possibility of retrieving ecosystem light use efficiency (LUE, the carbon sequestered per unit photosynthetically active radiation) directly from satellite observations. Our novel approach has been to compare LUE derived from tower fluxes with LUE estimated using spectral indices computed from MODIS satellite observations over forests in the Fluxnet-Canada Research Network, using the MODIS narrow ocean bands acquired over land. We matched carbon flux data collected around the time of the MODIS mid-day overpass for over one hundred relatively clear days in five years (2001-2006) from a mature Douglas fir forest in British Columbia. We also examined hyperspectral reflectance data collected diurnally from the tower in conjunction with the eddy correlation fluxes and meteorological measurements made throughout the 2006 growing season at this site. The tower-based flux data provided an opportunity to examine diurnal and seasonal LUE processes and their relationship to spectral indices at the scale of the forest stand. We evaluated LUE in conjunction with the Photochemical Reflectance Index (PRI), a normalized difference spectral index that uses 531 nm and a reference band to capture responses to high light induced stress afforded by the xanthophyll cycle. Canopy structure information, retrieved from airborne laser scanning radar (LiDAR) observations, was used to partition the forest canopy into sunlit and shaded fractions throughout the day, on numerous days during 2006. At each observation period throughout a day, the PRI was examined for the sunlit, shaded, and intermediate canopy segments defined by their instantaneous position relative to the solar principal plane (SPP). The sunlit sector was associated with the illumination "hotspot" (the reflectance backscatter maximum), the shaded sector with the "cold or dark spot" (the

  13. Operationalizing ecosystem-based adaptation: harnessing ecosystem services to buffer communities against climate change

    Directory of Open Access Journals (Sweden)

    Christine Wamsler

    2016-03-01

    Full Text Available Ecosystem-based approaches for climate change adaptation are promoted at international, national, and local levels by both scholars and practitioners. However, local planning practices that support these approaches are scattered, and measures are neither systematically implemented nor comprehensively reviewed. Against this background, this paper advances the operationalization of ecosystem-based adaptation by improving our knowledge of how ecosystem-based approaches can be considered in local planning (operational governance level. We review current research on ecosystem services in urban areas and examine four Swedish coastal municipalities to identify the key characteristics of both implemented and planned measures that support ecosystem-based adaptation. The results show that many of the measures that have been implemented focus on biodiversity rather than climate change adaptation, which is an important factor in only around half of all measures. Furthermore, existing measures are limited in their focus regarding the ecological structures and the ecosystem services they support, and the hazards and risk factors they address. We conclude that a more comprehensive approach to sustainable ecosystem-based adaptation planning and its systematic mainstreaming is required. Our framework for the analysis of ecosystem-based adaptation measures proved to be useful in identifying how ecosystem-related matters are addressed in current practice and strategic planning, and in providing knowledge on how ecosystem-based adaptation can further be considered in urban planning practice. Such a systematic analysis framework can reveal the ecological structures, related ecosystem services, and risk-reducing approaches that are missing and why. This informs the discussion about why specific measures are not considered and provides pathways for alternate measures/designs, related operations, and policy processes at different scales that can foster sustainable

  14. Ecosystem services in ECOCLIM

    DEFF Research Database (Denmark)

    Sørensen, Lise Lotte; Boegh, Eva; Bendtsen, J;

    that actions initiated to reduce anthropogenic GHG emissions are sustainable and not destructive to existing ecosystem services. Therefore it is important to address i.e. land use change in relation to the regulating services of the ecosystems, such as carbon sequestration and climate regulation. At present...... a thorough understanding of the ecosystem processes controlling the uptake or emissions of GHG is fundamental. Here we present ECOCLIM in the context of ecosystem services and the experimental studies within ECOCLIM which will lead to an enhanced understanding of Danish ecosystems....

  15. Reviewing the health of software ecosystems – a conceptual framework proposal

    DEFF Research Database (Denmark)

    Manikas, Konstantinos; Hansen, Klaus Marius

    2013-01-01

    and evaluate health. In this work, we review the literature related to the concept of software ecosystem health and the literature that inspired the software ecosystem health literature (a total of 23 papers) and (i) identify that the main source of inspiration is the health of business ecosystems while also......The health of a software ecosystem is an indication of how well the ecosystem is functioning. The measurement of health can point to issues that need to be addressed in the ecosystem and areas for the ecosystem to improve. However, the software ecosystem field lacks an applicable way to measure...... influenced by theories from natural ecosystems and open source, (ii) identify two areas where software ecosystems differ from business and natural ecosystems, and (iii) propose a conceptual framework for defining and measuring the health of software ecosystems....

  16. Fishing for ecosystem services.

    Science.gov (United States)

    Pope, Kevin L; Pegg, Mark A; Cole, Nicholas W; Siddons, Stephen F; Fedele, Alexis D; Harmon, Brian S; Ruskamp, Ryan L; Turner, Dylan R; Uerling, Caleb C

    2016-12-01

    Ecosystems are commonly exploited and manipulated to maximize certain human benefits. Such changes can degrade systems, leading to cascading negative effects that may be initially undetected, yet ultimately result in a reduction, or complete loss, of certain valuable ecosystem services. Ecosystem-based management is intended to maintain ecosystem quality and minimize the risk of irreversible change to natural assemblages of species and to ecosystem processes while obtaining and maintaining long-term socioeconomic benefits. We discuss policy decisions in fishery management related to commonly manipulated environments with a focus on influences to ecosystem services. By focusing on broader scales, managing for ecosystem services, and taking a more proactive approach, we expect sustainable, quality fisheries that are resilient to future disturbances. To that end, we contend that: (1) management always involves tradeoffs; (2) explicit management of fisheries for ecosystem services could facilitate a transition from reactive to proactive management; and (3) adaptive co-management is a process that could enhance management for ecosystem services. We propose adaptive co-management with an ecosystem service framework where actions are implemented within ecosystem boundaries, rather than political boundaries, through strong interjurisdictional relationships. Published by Elsevier Ltd.

  17. Fishing for ecosystem services

    Science.gov (United States)

    Pope, Kevin L.; Pegg, Mark A.; Cole, Nicholas W.; Siddons, Stephen F.; Fedele, Alexis D.; Harmon, Brian S.; Ruskamp, Ryan L.; Turner, Dylan R.; Uerling, Caleb C.

    2016-01-01

    Ecosystems are commonly exploited and manipulated to maximize certain human benefits. Such changes can degrade systems, leading to cascading negative effects that may be initially undetected, yet ultimately result in a reduction, or complete loss, of certain valuable ecosystem services. Ecosystem-based management is intended to maintain ecosystem quality and minimize the risk of irreversible change to natural assemblages of species and to ecosystem processes while obtaining and maintaining long-term socioeconomic benefits. We discuss policy decisions in fishery management related to commonly manipulated environments with a focus on influences to ecosystem services. By focusing on broader scales, managing for ecosystem services, and taking a more proactive approach, we expect sustainable, quality fisheries that are resilient to future disturbances. To that end, we contend that: (1) management always involves tradeoffs; (2) explicit management of fisheries for ecosystem services could facilitate a transition from reactive to proactive management; and (3) adaptive co-management is a process that could enhance management for ecosystem services. We propose adaptive co-management with an ecosystem service framework where actions are implemented within ecosystem boundaries, rather than political boundaries, through strong interjurisdictional relationships.

  18. Influence Factors of Forest Ecosystem Carbon Sequestration and Its Regulation Measurements in Jiangxi Province%森林生态系统碳汇影响因子及其江西省调控措施

    Institute of Scientific and Technical Information of China (English)

    张秋根; 张扬建; 熊辉

    2015-01-01

    森林生态系统由于自身强大光合作用而成为陆地生态系统中最为重要的碳库,但自然因素和人为因素的干扰会影响森林生态系统的碳汇功能的稳定性,甚至导致森林生态系统碳收支能力下降并转变为碳"源".从气候因子、地形因子、土壤因子、生物因子和人为因子等方面概述了影响森林生态系统碳汇的影响因子. 结合江西省森林现状,从科学利用自然条件、优化调整森林结构、加强森林封育保护、提升森林经营水平、提高现有森林质量5个方面提出了提高江西省森林生态系统碳汇功能的调控措施.%Forest ecosystem is the most important carbon library in the terrestrial ecosystem because of its stronger photosynthesis,but the change of the natural factors and human factors will affect the stability of forest ecosystem carbon sequestration. Even the carbon balance ability of a few forest eco-systems become to fall and turn into the carbon source. The influence factors of forest ecosystem car-bon sequestration were overviewed including climate factors, terrain factors, soil factors, biological factors and human factors. Combined with the present situation of forest in Jiangxi province,the regu-lation measurements were put forward to improve the carbon sequestration function for forest ecosys-tem in Jiangxi province,which including scientific use of natural conditions,optimization and adjust-ment forest structure,strengthening forest nurture and protection,enhancing forest management level and improving the quality of existing forest.

  19. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these...

  20. Response of the herbaceous layer to snow variability at the south margin of the Gurbantonggut Desert of China%古尔班通古特沙漠南缘草本层对积雪变化的响应

    Institute of Scientific and Technical Information of China (English)

    范连连; 马健; 吴林峰; 徐贵青; 李彦; 唐立松

    2012-01-01

    thickness affects the ecological and physiological traits of the herbaceous layer in a typical arid zone. Methods We used five treatments of snow thickness (0, 50%, 100%, 150% and 200%), and natural snow thickness (100%) was the control. We investigated species number, coverage, density and height of plants in 1 m × 1 m quadrats and used the harvest method to measure aboveground biomass of both the herbaceous layer and the dominant species (Nepeta micrantha).Important findings Seedling density of the herbaceous layer was positively correlated with the amount of snow, but average height was negatively correlated with it. Also, total aboveground biomass and number of species showed no significant differences among treatments. Plant height and aboveground biomass of the individual dominants were negatively correlated with the amount of snow. For other species in the layer, the average height was also negatively correlated with the snow thickness. The number of seeds germinating and the abundance of herbaceous plants increased with the amount of snow, but species richness was not influenced by snow thickness. Our results suggested that although melted snow is the main water source for herbaceous plants, they have developed a strong buffering capacity against variation in the snow thickness. Therefore, species diversity and net primary productivity of the herbaceous layer can be stable even under strong variation of snow accumulation.

  1. Spatial variation in the structure and composition of the herbaceous community in a semiarid region of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    KA. Silva

    Full Text Available In the arid and semiarid environments of the world, microhabitats serve as models for the structure of vegetation communities. The goal of this study was to identify differences in the structures of the herbaceous communities growing on a crystalline substrate and those growing on a sedimentary substrate in a semiarid region of northeastern Brazil. One hundred 1 × 1 m plots were established in each area for quantitative sampling, with 69 species recorded in the crystalline area and 76 in the sedimentary area. The average plant density was higher in the sedimentary area, and average diameters and heights were greater in the crystalline area. The families and species with a high Importance Value Index (IVI and a high Mixed Ecological Value Index (MEVI differed between the areas. Of the species with high densities, only four were found in both areas. Shannon-Weiner diversity index values in the crystalline (2.96 nats/ind.-1 and sedimentary (2.89 nats/ind.-1 areas were similar. Evenness values on both substrates were also similar (0.72 and 0.71 in the crystalline and sedimentary areas, respectively. This study shows that variations in plant establishment conditions between crystalline and sedimentary areas in a semiarid region of northeastern Brazil should be considered as structure-modeling factors for the herbaceous community.

  2. Effect of aerotechnogenic emissions on the content of heavy metals in herbaceous plants of the Lower Don region

    Science.gov (United States)

    Minkina, T. M.; Mandzhieva, S. S.; Chaplygin, V. A.; Motuzova, G. V.; Burachevskaya, M. V.; Bauer, T. V.; Sushkova, S. N.; Nevidomskaya, D. G.

    2017-06-01

    The effect of soil properties and distance from the source of technogenic emission on the input of Pb, Zn, Cd, Cu, Mn, Cr, and Ni into daisy family plants ( Asteraceae) has been studied. It has been found that the high level of anthropogenic load related to the atmospheric emissions from the Novocherkassk power plant (NPP) favors the accumulation of heavy metals (HMs) in herbaceous plants. Contamination with Pb, Cd, Cr, and Ni is revealed in plants growing near the NPP. The main factors affecting the distribution of HMs in the above- and underground organs of plants include individual physiological features of plant species controlling the barrier functions of different plant organs. Ambrosia artemisiifolia L., Artemisia austriaca Pall. ex. Wild. Jack., and Tanacetum vulgare L. are accumulators of HMs. The resistance of herbaceous plants to pollution has been determined from the acropetal coefficient and actual biogeochemical mobility of HMs. Ambrosia artemisiifolia L. is most resistant to contamination with Mn; Achillea nobilis L. is most resistant to Pb, Ni, and Cd; Cichorium intybus L. is most resistant to Zn and Cu.

  3. Trophic relations of Opatrum sabulosum (Coleoptera, Tenebrionidae with leaves of cultivated and uncultivated species of herbaceous plants under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Viktor Brygadyrenko

    2015-02-01

    Full Text Available We carried out a quantitative assessment of the consumption of herbaceous plants by Opatrum sabulosum (Linnaeus, 1761 – a highly significant agricultural pest species. We researched the feeding preferences of this pest species with respect to 33 uncultivated and 22 cultivated plant species. This species of darkling beetle feeds on many uncultivated plant species, including those with hairy leaves and bitter milky sap, such as Scabiosa ucrainca (5.21 mg/specimen/24 hours, Euphorbia virgata (3.45, Solanum nigrum (3.32, Centauria scabiosa (2.47, Lamium album (2.41, Aristolochia clematitis (1.76, Chenopodium album (1.73, Arctium lappa (1.51, Asperula odorata (1.20. A high rate of leaf consumption is also characteristic for cultivated species, for example, Perilla nankinensis (5.05 mg/specimen/24 hours, Lycopersicon esculentum (3.75, Tropaeolum majus (3.29, Nicotiana tabacum (2.66, Rumex acetosa (1.96, Beta vulgaris (1.27. O. sabulosum is capable of feeding on plants which are poisonous to cattle. This species of darkling beetle consumes 95.5% of the cultivated and 48.5% of the uncultivated herbaceous plants researched.

  4. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China): MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory-derived NO emission from soil samples

    Science.gov (United States)

    Mamtimin, B.; Behrendt, T.; Badawy, M. M.; Wagner, T.; Qi, Y.; Wu, Z.; Meixner, F. X.

    2015-01-01

    We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis centre, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i) soil moisture and (ii) soil temperature of Milan oasis (iii) different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert) were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol Transport) was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three-dimensional (3-D) NO concentrations (30 m horizontal resolution) have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modelled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration) of measured and simulated slant (as well as vertical) NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory-derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2) to the size of an entire agricultural

  5. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China): MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory derived NO emission from soil samples

    Science.gov (United States)

    Mamtimin, B.; Behrendt, T.; Badawy, M. M.; Wagner, T.; Qi, Y.; Wu, Z.; Meixner, F. X.

    2014-07-01

    We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW-China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis center, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i) soil moisture and (ii) soil temperature of Milan oasis' (iii) different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert) were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol-Transport) was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three dimensional NO concentrations (30 m horizontal resolution) have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modeled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration) of measured and simulated slant (as well as vertical) NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2) to the size of an entire agricultural

  6. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China: MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory derived NO emission from soil samples

    Directory of Open Access Journals (Sweden)

    B. Mamtimin

    2014-07-01

    Full Text Available We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW-China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis center, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i soil moisture and (ii soil temperature of Milan oasis' (iii different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol-Transport was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three dimensional NO concentrations (30 m horizontal resolution have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modeled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration of measured and simulated slant (as well as vertical NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2 to the size of an entire

  7. On the estimate of the transpiration in Mediterranean heterogeneous ecosystems with the coupled use of eddy covariance and sap flow techniques.

    Science.gov (United States)

    Corona, Roberto; Curreli, Matteo; Montaldo, Nicola; Oren, Ram

    2013-04-01

    Mediterranean ecosystems are commonly heterogeneous savanna-like ecosystems, with contrasting plant functional types (PFT) competing for the water use. Mediterranean regions suffer water scarcity due to the dry climate conditions. In semi-arid regions evapotranspiration (ET) is the leading loss term of the root-zone water budget with a yearly magnitude that may be roughly equal to the precipitation. Despite the attention these ecosystems are receiving, a general lack of knowledge persists about the estimate of ET and the relationship between ET and the plant survival strategies for the different PFTs under water stress. During the dry summers these water-limited heterogeneous ecosystems are mainly characterized by a simple dual PFT-landscapes with strong-resistant woody vegetation and bare soil since grass died. In these conditions due to the low signal of the land surface fluxes captured by the sonic anemometer and gas analyzer the widely used eddy covariance may fail and its ET estimate is not robust enough. In these conditions the use of the sap flow technique may have a key role, because theoretically it provides a direct estimate of the woody vegetation transpiration. Through the coupled use of the sap flow sensor observations, a 2D foot print model of the eddy covariance tower and high resolution satellite images for the estimate of the foot print land cover map, the eddy covariance measurements can be correctly interpreted, and ET components (bare soil evaporation and woody vegetation transpiration) can be separated. The case study is at the Orroli site in Sardinia (Italy). The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and cork oaks, different shrubs and herbaceous species. An extensive field campaign started in 2004. Land-surface fluxes and CO2 fluxes are estimated by an eddy covariance technique based micrometeorological tower. Soil moisture profiles were also continuously estimated using water

  8. Fire alters ecosystem carbon and nutrients but not plant nutrient stoichiometry or composition in tropical savanna.

    Science.gov (United States)

    Pellegrini, Adam F A; Hedin, Lars O; Staver, A Carla; Govender, Navashni

    2015-05-01

    Fire and nutrients interact to influence the global distribution and dynamics of the savanna biome, but the results of these interactions are both complex and poorly known. A critical but unresolved question is whether short-term losses of carbon and nutrients caused by fire can trigger long-term and potentially compensatory responses in the nutrient stoichiometry of plants, or in the abundance of dinitrogen-fixing trees. There is disagreement in the literature about the potential role of fire on savanna nutrients, and, in turn, on plant stoichiometry and composition. A major limitation has been the lack of fire manipulations over time scales sufficiently long for these interactions to emerge. We use a 58-year, replicated, large-scale, fire manipulation experiment in Kruger National Park (South Africa) in savanna to quantify the effect of fire on (1) distributions of carbon, nitrogen, and phosphorus at the ecosystem scale; (2) carbon: nitrogen: phosphorus stoichiometry of above- and belowground tissues of plant species; and (3) abundance of plant functional groups including nitrogen fixers. Our results show dramatic effects of fire on the relative distribution of nutrients in soils, but that individual plant stoichiometry and plant community composition remained unexpectedly resilient. Moreover, measures of nutrients and carbon stable isotopes allowed us to discount the role of tree cover change in favor of the turnover of herbaceous biomass as the primary mechanism that mediates a transition from low to high 'soil carbon and nutrients in the absence of fire. We conclude that, in contrast to extra-tropical grasslands or closed-canopy forests, vegetation in the savanna biome may be uniquely adapted to nutrient losses caused by recurring fire.

  9. Growing season variability of net ecosystem CO2 exchange and evapotranspiration of a sphagnum mire in the broad-leaved forest zone of European Russia

    Science.gov (United States)

    Olchev, A.; Volkova, E.; Karataeva, T.; Novenko, E.

    2013-09-01

    The spatial and temporal variability of net ecosystem exchange (NEE) of CO2 and evapotranspiration (ET) of a karst-hole sphagnum peat mire situated at the boundary between broad-leaved and forest-steppe zones in the central part of European Russia in the Tula region was described using results from field measurements. NEE and ET were measured using a portable measuring system consisting of a transparent ventilated chamber combined with an infrared CO2/H2O analyzer, LI-840A (Li-Cor, USA) along a transect from the southern peripheral part of the mire to its center under sunny clear-sky weather conditions in the period from May to September of 2012 and in May 2013. The results of the field measurements showed significant spatial and temporal variability of NEE and ET that was mainly influenced by incoming solar radiation and ground water level. The seasonal patterns of NEE and ET within the mire were quite different. During the entire growing season the central part of the mire was a sink of CO2 for the atmosphere. NEE reached maximal values in June-July (-6.8 ± 4.2 μmol m-2 s-1). The southern peripheral part of the mire, due to strong shading by the surrounding forest, was a sink of CO2 for the atmosphere in June-July only. ET reached maximal values in the well-lighted central parts of the mire in May (0.34 ± 0.20 mm h-1) mainly because of high air and surface temperatures and the very wet upper peat horizon and sphagnum moss. Herbaceous species made the maximum contribution to the total gross primary production (GPP) in both the central and the peripheral parts of the mire. The contribution of sphagnum to the total GPP of these plant communities was relatively small and ranged on sunny days of July-August from -1.1 ± 1.1 mgC g-1 of dry weight (DW) per hour in the peripheral zone of the mire to -0.6 ± 0.2 mgC g-1 DW h-1 at the mire center. The sphagnum layer made the maximum contribution to total ET at the mire center (0.25 ± 0.10 mm h-1) and the herbaceous

  10. The Multifaceted Aspects of Ecosystem Integrity

    Directory of Open Access Journals (Sweden)

    Simon A. Levin

    1997-06-01

    Full Text Available The need to reduce human impacts on ecosystems creates pressure for adequate response, but the rush to solutions fosters the oversimplification of such notions as sustainable development and ecosystem health. Hence, it favors the tendency to ignore the complexity of natural systems. In this paper, after a brief analysis of the use and abuse of the notion of ecosystem health, we address the problem of a sound definition of ecosystem integrity, critically review the different methodological and conceptual approaches to the management of natural resources, and sketch the practical implications stemming from their implementation. We show thatthere are merits and limitations in different definitions of ecosystem integrity, for each acknowledges different aspects of ecosystem structure and functioning and reflects the subjective perspectives of humans on the value, importance, and role of biological diversity. This evaluation is based on a brief sketch of the links among biodiversity, ecosystem functioning and resilience, and a description of the problems that arise in distinguishing between natural and anthropogenic disturbance. We also emphasize the difficulty of assessing the economic value of species and habitats and the need to use adaptive management policies to deal with uncertainty and ecosystem complexity. In conclusion, while acknowledging that environmental legislation requires objective statements on ecosystem status and trends, we stress that the notion of ecological integrity is so complex that its measure cannot be expressed through a single indicator, but rather requires a set of indicators at different spatial, temporal, and hierarchical levels of ecosystem organization. Ecosystem integrity is not an absolute, monolithic concept. The existence of different sets of values regarding biological diversity and environmental risks must be explicitly accounted for and incorporated in the decision process, rather than ignored or averaged out.

  11. Managed island ecosystems

    Science.gov (United States)

    McEachern, Kathryn; Atwater, Tanya; Collins, Paul W.; Faulkner, Kate R.; Richards, Daniel V.

    2016-01-01

    This long-anticipated reference and sourcebook for California’s remarkable ecological abundance provides an integrated assessment of each major ecosystem type—its distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of California’s ecological patterns and the history of the state’s various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the state’s ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of California’s environment and curious naturalists.

  12. Sensors for observing ecosystem status

    Directory of Open Access Journals (Sweden)

    S. Kröger

    2009-04-01

    Full Text Available This paper aims to review the availability and application of sensors for observing marine ecosystem status. It gives a broad overview of important ecosystem variables to be investigated, such as biogeochemical cycles, primary and secondary production, species distribution, animal movements, habitats and pollutants. Some relevant legislative drivers are listed, as they provide one context in which ecosystem studies are undertaken. In addition to literature cited within the text the paper contains some useful web links to assist the reader in making an informed instrument choice, as the authors feel that the topic is so broad, it is impossible to discuss all relevant systems or to provide appropriate detail for those discussed. This is therefore an introduction to how and why ecosystem status is currently observed, what variables are quantified, from what platforms, using remote sensing or in-situ measurements, and gives examples of useful sensor based tools. Starting with those presently available, to those under development and also highlighting sensors not yet realised but desirable for future studies.

  13. Sensors for observing ecosystem status

    Directory of Open Access Journals (Sweden)

    S. Kröger

    2009-11-01

    Full Text Available This paper aims to review the availability and application of sensors for observing marine ecosystem status. It gives a broad overview of important ecosystem variables to be investigated, such as biogeochemical cycles, primary and secondary production, species distribution, animal movements, habitats and pollutants. Some relevant legislative drivers are listed, as they provide one context in which ecosystem studies are undertaken. In addition to literature cited within the text the paper contains some useful web links to assist the reader in making an informed instrument choice, as the authors feel that the topic is so broad, it is impossible to discuss all relevant systems or to provide appropriate detail for those discussed. It is therefore an introduction to how and why ecosystem status is currently observed, what variables are quantified, from what platforms, using remote sensing or in-situ measurements, and gives examples of useful sensor based tools. Starting with those presently available, to those under development and also highlighting sensors not yet realised but desirable for future studies.

  14. BUSINESS ECOSYSTEMS VS BUSINESS DIGITAL ECOSYSTEMS

    Directory of Open Access Journals (Sweden)

    Marinela Lazarica

    2006-05-01

    Full Text Available E-business is often described as the small organisations’ gateway to global business and markets. The adoption of Internet-based technologies for e-business is a continuous process, with sequential steps of evolution. The latter step in the adoption of Internet-based technologies for business, where the business services and the software components are supported by a pervasive software environment, which shows an evolutionary and self-organising behaviour are named digital business ecosystems. The digital business ecosystems are characterized by intelligent software components and services, knowledge transfer, interactive training frameworks and integration of business processes and e-government models.

  15. [Assessing forest ecosystem health I. Model, method, and index system].

    Science.gov (United States)

    Chen, Gao; Dai, Limin; Ji, Lanzhu; Deng, Hongbing; Hao, Zhanqing; Wang, Qingli

    2004-10-01

    Ecosystem health assessment is one of the main researches and urgent tasks of ecosystem science in 21st century. An operational definition on ecosystem health and an all-sided, simple, easy operational and standard index system, which are the foundation of assessment on ecosystem health, are necessary in obtaining a simple and applicable assessment theory and method of ecosystem health. Taking the Korean pine and broadleaved mixed forest ecosystem as an example, an originally creative idea on ecosystem health was put forward in this paper based on the idea of mode ecosystem set and the idea of forest ecosystem health, together with its assessment. This creative idea can help understand what ecosystem health is. Finally, a formula was deduced based on a new effective health assessment method--health distance (HD), which is the first time to be brought forward in China. At the same time, aiming at it's characteristics by status understanding and material health questions, a health index system of Korean pine and broadleaved mixed forest ecosystem was put forward in this paper, which is a compound ecosystem based on the compound properties of nature, economy and society. It is concrete enough to measure sub-index, so it is the foundation to assess ecosystem health of Korean pine and broadleaved mixed forest in next researches.

  16. Funding and stimulation mechanisms of the wetlands` ecosystem services conservation

    Directory of Open Access Journals (Sweden)

    N.V. Degtyar

    2013-12-01

    Full Text Available The aim of the article. The aim of the article is to study the problems of funding conservation of wetlands ecosystem services and search of organizational and economic management tools of ecosystem services, which can be implemented in Ukraine. The results of the analysis. Summary of world practice implementation of organizational and economic management tools, based on payments for wetlands ecosystem services, determine the following basic principles of their formation: 1 enter into an agreement with stakeholders payment for ecosystem services on a voluntary basis; 2 payment perform beneficiaries of ecosystem services; 3 payments are made directly to providers of ecosystem services; 4 ecosystem value should prevail over the market interests of the ecosystem services provider; 5 payment is usually carried out by a wetland ecosystem services, although, in some cases, for receiving payments may be to force a certain way of land use, etc. The author generalized and systematized modern tools that are used to manage wetlands ecosystem services. Therefore, the author proposed to allocate financial and organizational tools of ecosystem services management into separate groups. Moreover, financial instruments can be divided into public and private (or voluntary. The government funding instruments primarily include national (local target program and budget, reduced taxes, duties and tariffs, government guarantees of financial transactions of wetland ecosystem services and securitization, joint financing, credit and deposit activities on wetland ecosystem services, etc. Conclusions and directions of further researches. In Ukraine the formation of organizational and economic tools of wetlands ecosystem services managing which is based primarily on a system of payments for ecosystem services needs to take into account the following measures: conducting thorough strategic research and applied ecological, economic and other sectorial studies, conducting

  17. On the Karst Ecosystem

    Institute of Scientific and Technical Information of China (English)

    袁道先

    2001-01-01

    In this paper the author gives a definition of the karst ecosystem and discusses the characteristics of the karst environment and karst ecosystem and the relationship between life and the karst environment. Finally he clarifies the structure, driving force and functions of the karst system.``

  18. Ecosystem Impacts of Woody Encroachment In Texas: A Spatial Analysis Using AVIRIS

    Science.gov (United States)

    Martin, Roberta E.; Asner, Gregory P.

    2004-01-01

    Woody encroachment, the increase of woody plant density relative to herbaceous vegetation, has been documented in drylands of Texas as well as worldwide (Archer 1994, Harrington and Harman 1995, Moleele et al. 2002). Over-grazing, fire suppression and climate change are implicated in the shift from open grasslands to ecosystems now populated by trees and shrubs (Scholes and Archer 1997, Archer et al. 2001), such as Prosopis glandulosa var. glandulosa (honey mesquite) in north Texas (Teague et al. 1997, Ansley et al. 2001, Asner et al. 2003a). Several studies have examined changes in ecosystem properties accompanying woody vegetation encroachment in the Southwest U.S., with research focused on increases in plant and soil carbon (C) and nitrogen (N) stores (Hoffman and Jackson 2000, Asner et al. 2003a), isotopic shifts in these pools (Boutton 1999, Archer et al. 2001), and increases in N cycling rates (Rundel et al. 1982, Hibbard et al. 2001). However, little is known regarding the impact of woody encroachment on N trace gas emissions from dryland regions such as Texas. NOx is produced in the soil during the processes of nitrification and denitrification (Firestone and Davidson 1989). The total N efflux from soils is most directly influenced by the internal cycling of N, which at a regionalscale, is controlled by the inputs and availability of N from vegetation via litterfall and subsequent decomposition (Robertson et al. 1989). Although plot-scale studies are critical to understanding controls over N oxide emissions, regionalization of the measurements is impeded by spatial variation in the factors contributing most to N cycling processes: soil properties (affecting soil moisture regimes and N stocks) and vegetation cover (affecting litter inputs and N uptake). While broad patterns in ecosystem structure and vegetation composition co-vary with general patterns of trace gas emissions (Matson 1997), there is no easily measured index of N availability that can be

  19. Effect of atmospheric CO 2 enrichment on rubisco content in herbaceous species from high and low altitude

    Science.gov (United States)

    Sage, Rowan F.; Schäppi, Bernd; Körner, Christian

    Atmospheric CO 2 enrichment reduces Rubisco content in many species grown in controlled environments; however, relatively few studies have examined CO 2 effects on Rubisco content of plants grown in their natural habitat. We examined the response of Rubisco content to atmospheric CO 2 enrichment (600-680 μmol mol -1 in place of ppm) in 5 herbaceous species growing in a low altitude grassland (550 m) near Basel, Switzerland, and 3 herbaceous species from Swiss alpine grassland at 2470 m. At low elevation, the dominant grass Bromus erectus and the subdominant dicot Sanquisorba minor exhibited 20% to 25% reduction of Rubisco content following high CO 2 exposure; no CO 2 effect was observed in the subdominants Carex flacca, Lotus corniculatus and Trifolium repens. At the Alpine site, the subdominant grass Poa alpina maintained 27% less Rubisco content when grown at high CO 2 while the co-dominant forb Leontodon helveticus had 19% less Rubisco in high CO 2. Rubisco content was unaffected in the tundra dominant Carex curvula. Because the degree of Rubisco modulation was similar between high and low elevation sites, it does not appear that differences in local partial pressure of CO 2 (altitude) or differences in stress in general induce different patterns of modulation of photosynthetic capacity in response to high CO 2. In addition, the degree of Rubisco reduction (<30%) was less than might be indicated by the low biomass response to CO 2 enrichment previously observed at these sites. Thus, plants in Swiss lowland and alpine grassland appear to maintain greater Rubisco concentration and photosynthetic capacity than whole plants can effectively exploit in terms of harvestable biomass.

  20. Ecosystem Viable Yields

    CERN Document Server

    De Lara, Michel; Oliveros-Ramos, Ricardo; Tam, Jorge

    2011-01-01

    The World Summit on Sustainable Development (Johannesburg, 2002) encouraged the application of the ecosystem approach by 2010. However, at the same Summit, the signatory States undertook to restore and exploit their stocks at maximum sustainable yield (MSY), a concept and practice without ecosystemic dimension, since MSY is computed species by species, on the basis of a monospecific model. Acknowledging this gap, we propose a definition of "ecosystem viable yields" (EVY) as yields compatible i) with biological viability levels for all time and ii) with an ecosystem dynamics. To the difference of MSY, this notion is not based on equilibrium, but on viability theory, which offers advantages for robustness. For a generic class of multispecies models with harvesting, we provide explicit expressions for the EVY. We apply our approach to the anchovy--hake couple in the Peruvian upwelling ecosystem between the years 1971 and 1981.

  1. Restoring a disappearing ecosystem: the Longleaf Pine Savanna.

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Timothy B. [USFS; Miller, Karl V. [University of Georgia; Park, Noreen

    2013-05-01

    Longleaf pine (Pinus palustris) savannas of the southeastern United States contain some of the worlds most diverse plant communities, along with a unique complement of wildlife. Their traditionally open canopy structure and rich understory of grasses and herbs were critical to their vigor. However, a long history of land-use practices such as logging, farming, and fire exclusion have reduced this once-widespread ecosystem to only 3 percent of its original range. At six longleaf pine plantations in South Carolina, Tim Harrington with the Pacific Northwest Research Station and collaborators with the Southern Research Station used various treatments (including prescribed burns, tree thinning, and herbicide applications) to alter the forest structure and tracked how successful each one was in advancing savanna restoration over a 14-year period. They found that typical planting densities for wood production in plantations create dense understory shade that excludes many native herbaceous species important to savannas and associated wildlife. The scientists found that although tree thinning alone did not result in sustained gains, a combination of controlled burning, thinning, and herbicide treatments to reduce woody plants was an effective strategy for recovering the savanna ecosystem. The scientists also found that these efforts must be repeated periodically for enduring benefits.

  2. Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.

    Science.gov (United States)

    Fortier, Julien; Truax, Benoit; Gagnon, Daniel; Lambert, France

    2015-05-01

    In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the

  3. INTERACTIONS BETWEEN THE HERBACEOUS AND SHRUBBY-ARBOREAL COMPONENTS IN A SEMIARID REGION IN THE NORTHEAST OF BRAZIL: COMPETITION OR FACILITATION?

    Directory of Open Access Journals (Sweden)

    KLEBER ANDRADE DA SILVA

    2015-01-01

    Full Text Available Under conditions of high stress, interactions between species can be positive. Islands of perennial vegetation can improve the conditions of the understory and facilitate the establishment of herbaceous plants. The hypothesis of this study is that islands of perennial vegetation in an area of caatinga harbor, a greater richness, diversity and density of herbaceous plants, and that individuals reach a greater height and diameter than in open spaces. The study was conducted in Petrolândia, Pernambuco, Brazil. Twenty-seven plots were installed in the center of the islands, 38 at the edge of the islands (in a total of 38 islands and 35 in the open spaces. A total of 51 species were recorded in the center and 55 on the edge of the islands and 48 in the open spaces. The mean richness of the open spaces was lower than on the islands. The diversity was greater in the center of the island and became less on the edge of the island and in the open spaces. The mean density was lower in the open spaces than on the islands. The mean density at the edge of the islands was greater than in the center of the islands. There was no difference in mean diameter of herbaceous plants. The mean height of the individuals was higher in the center of the islands. The herbaceous community growing on the islands exhibited higher richness, diversity, density and height than in open spaces. Thus, islands of perennial vegetation facilitate the establishment of herbaceous species.

  4. Ecosystem approach in education

    Science.gov (United States)

    Nabiullin, Iskander

    2017-04-01

    Environmental education is a base for sustainable development. Therefore, in our school we pay great attention to environmental education. Environmental education in our school is based on ecosystem approach. What is an ecosystem approach? Ecosystem is a fundamental concept of ecology. Living organisms and their non-living environments interact with each other as a system, and the biosphere planet functions as a global ecosystem. Therefore, it is necessary for children to understand relationships in ecosystems, and we have to develop systems thinking in our students. Ecosystem approach and systems thinking should help us to solve global environmental problems. How do we implement the ecosystem approach? Students must understand that our biosphere functions as a single ecosystem and even small changes can lead to environmental disasters. Even the disappearance of one plant or animal species can lead to irreversible consequences. So in the classroom we learn the importance of each living organism for the nature. We pay special attention to endangered species, which are listed in the Red Data List. Kids are doing projects about these organisms, make videos, print brochures and newspapers. Fieldwork also plays an important role for ecosystem approach. Every summer, we go out for expeditions to study species of plants and animals listed in the Red Data List of Tatarstan. In class, students often write essays on behalf of any endangered species of plants or animals, this also helps them to understand the importance of each living organism in nature. Each spring we organise a festival of environmental projects among students. Groups of 4-5 students work on a solution of environmental problems, such as water, air or soil pollution, waste recycling, the loss of biodiversity, etc. Participants shoot a clip about their project, print brochures. Furthermore, some of the students participate in national and international scientific Olympiads with their projects. In addition to

  5. Quantum and Ecosystem Entropies

    Directory of Open Access Journals (Sweden)

    A. D. Kirwan

    2008-06-01

    Full Text Available Ecosystems and quantum gases share a number of superficial similarities including enormous numbers of interacting elements and the fundamental role of energy in such interactions. A theory for the synthesis of data and prediction of new phenomena is well established in quantum statistical mechanics. The premise of this paper is that the reason a comparable unifying theory has not emerged in ecology is that a proper role for entropy has yet to be assigned. To this end, a phase space entropy model of ecosystems is developed. Specification of an ecosystem phase space cell size based on microbial mass, length, and time scales gives an ecosystem uncertainty parameter only about three orders of magnitude larger than Planck’s constant. Ecosystem equilibria is specified by conservation of biomass and total metabolic energy, along with the principle of maximum entropy at equilibria. Both Bose - Einstein and Fermi - Dirac equilibrium conditions arise in ecosystems applications. The paper concludes with a discussion of some broader aspects of an ecosystem phase space.

  6. Exposure of northern leopard frogs in the Green Bay ecosystem to polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans is measured by direct chemistry but not hepatic ethoxyresorufin-O-deethylase activity

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y.W.; Karasov, W.H.; Patnode, K.A.; Jefcoate, C.R.

    1999-10-01

    The authors measured concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in northern leopard frogs collected from the Green Bay ecosystem and explored the catalytic activity of hepatic cytochrome P450-associated monooxygenase (P450 enzyme) as a biomarker for exposure to aryl hydrocarbon receptor (AhR) agonists. The two hypotheses tested were PCH concentrations in northern leopard frogs would be positively correlated with sediment polychlorinated hydrocarbon (PCH) levels in wetland habitats along a contamination gradient and hepatic ethoxyresorufin-O-deethylase (EROD) activity of northern leopard frogs, which is presumably mediated by aryl hydrocarbon receptor (AhR), would be positively correlated with PCH concentrations in frog carcasses from different collection sites. In 1994 and 1995, frogs from seven sites along the lower Fox River and Green Bay, USA, were assayed for hepatic EROD activities and whole carcass concentrations of PCBs, PCDDs, and PCDFs. Tissue total PCB concentrations ranging from 3 to 154 ng/g were significantly correlated with sediment PCB levels. Only one PCDD and two PCDFs at concentrations of 6 to 8 pg/g were found in the frogs collected with frog body weight and was similar among sites except for Peter's Marsh. No significant correlation was found between EROD activity and carcass PCB concentration. This result was consistent with the fact that the frogs collected from the Green Bay ecosystem had relatively low PCB concentrations compared with what was required for induction in the laboratory.

  7. Spatial and temporal variability of ground and satellite column measurements of NO2 and O3 over the Atlantic Ocean during the Deposition of Atmospheric Nitrogen to Coastal Ecosystems Experiment

    Science.gov (United States)

    Martins, Douglas K.; Najjar, Raymond G.; Tzortziou, Maria; Abuhassan, Nader; Thompson, Anne M.; Kollonige, Debra E.

    2016-12-01

    In situ measurements of O3 and nitrogen oxides (NO + NO2 ≡ NOx) and remote sensing measurements of total column NO2 and O3 were collected on a ship in the North Atlantic Ocean as part of the Deposition of Atmospheric Nitrogen to Coastal Ecosystems (DANCE) campaign in July-August 2014, 100 km east of the mid-Atlantic United States. Relatively clean conditions for both surface in situ mixing ratio and total column O3 and NO2 measurements were observed throughout the campaign. Increased surface and column NO2 and O3 amounts were observed when a terrestrial air mass was advected over the study region. Relative to ship-based total column measurements using a Pandora over the entire study, satellite measurements overestimated total column NO2 under these relatively clean atmospheric conditions over offshore waters by an average of 16%. Differences are most likely due to proximity, or lack thereof, to surface emissions; spatial averaging due to the field of view of the satellite instrument; and the lack of sensitivity of satellite measurements to the surface concentrations of pollutants. Total column O3 measurements from the shipboard Pandora showed good correlation with the satellite measurements (r = 0.96), but satellite measurements were 3% systematically higher than the ship measurements, in agreement with previous studies. Derived values of boundary layer height using the surface in situ and total column measurements of NO2 are much lower than modeled and satellite-retrieved boundary layer heights, which highlight the differences in the vertical distribution between terrestrial and marine environments.

  8. Application of the 15N gas-flux method for measuring in situ N2 and N2O fluxes due to denitrification in natural and semi-natural terrestrial ecosystems and comparison with the acetylene inhibition technique

    Science.gov (United States)

    Sgouridis, Fotis; Stott, Andrew; Ullah, Sami

    2016-03-01

    Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. 15N tracer approaches can provide in situ measurements of both N2 and N2O simultaneously, but their use has been limited to fertilized agro-ecosystems due to the need for large 15N additions in order to detect 15N2 production against the high atmospheric N2. For 15N-N2 analyses, we have used an "in-house" laboratory designed and manufactured N2 preparation instrument which can be interfaced to any commercial continuous flow isotope ratio mass spectrometer (CF-IRMS). The N2 prep unit has gas purification steps and a copper-based reduction furnace, and allows the analysis of small gas injection volumes (4 µL) for 15N-N2 analysis. For the analysis of N2O, an automated Tracegas Preconcentrator (Isoprime Ltd) coupled to an IRMS was used to measure the 15N-N2O (4 mL gas injection volume). Consequently, the coefficient of variation for the determination of isotope ratios for N2 in air and in standard N2O (0.5 ppm) was better than 0.5 %. The 15N gas-flux method was adapted for application in natural and semi-natural land use types (peatlands, forests, and grasslands) by lowering the 15N tracer application rate to 0.04-0.5 kg 15N ha-1. The minimum detectable flux rates were 4 µg N m-2 h-1 and 0.2 ng N m-2 h-1 for the N2 and N2O fluxes respectively. Total denitrification rates measured by the acetylene inhibition technique in the same land use types correlated (r = 0.58) with the denitrification rates measured under the 15N gas-flux method, but were underestimated by a factor of 4, and this was partially attributed to the incomplete inhibition of N2O reduction to N2, under a relatively high soil moisture content, and/or the catalytic NO decomposition in the presence of acetylene. Even though relatively robust for in situ denitrification measurements, methodological

  9. Current ecosystem processes in steppe near Lake Baikal

    Science.gov (United States)

    Vanteeva, Julia

    2015-04-01

    The steppes and forest steppes complexes of Priol'khonie at the Lake Baikal (southern Siberia, Russia) were studied in this research. Recreational activity has a significant impact on the Priol'khonie region. During soviet time this area was actively used for agriculture. Nowadays, this territory is the part of Pribaikalskyi National Park and special protection is needed. As the landscapes satisfy different human demands there are many land-management conflicts. The specific climate and soil conditions and human activity lead to erosion processes on study area. Sediment loads are transferred into the Lake Baikal and cause water pollution. Consequently, vegetation cover and phytomass play an important role for regulating hydrological processes in the ecosystems. The process of phytomass formation and its proactive role playing on sedimentation and mitigate silt detaching by rill and inter-rill erosion are considered in the research as important indicators of the ecosystem functions for steppe landscapes. These indicators were studied for the different land cover types identified on the area because the study area has a large variety of steppe and forest steppe complexes, differing in the form of relief, soil types, vegetation species composition and degree of land degradation. The fieldwork was conducted in the study area in the July and August of 2013. Thirty-two experimental sites (10 x 10 m) which characterized different types of ecosystem were established. The level of landscape degradation was estimated. The method of clipping was used for the valuation of above-ground herbaceous phytomass. The phytomass of tree stands was calculated using the volume-conversion rates for forest-steppe complexes. For the quantification of transferred silt by inter-rill erosion in different conditions (vegetation, slope, soil type, anthropogenic load) a portable rainfall simulator was created with taking into account the characteristics of the study area. The aboveground

  10. Application of the 15N-Gas Flux method for measuring in situ N2 and N2O fluxes due to denitrification in natural and semi-natural terrestrial ecosystems and comparison with the acetylene inhibition technique

    Science.gov (United States)

    Sgouridis, F.; Ullah, S.; Stott, A.

    2015-08-01

    Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. 15N tracer approaches can provide in situ measurements of both N2 and N2O simultaneously, but their use has been limited to fertilised agro-ecosystems due to the need for large 15N additions in order to detect 15N2 production against the high atmospheric N2. For 15N-N2 analyses, we have used an "in house" laboratory designed and manufactured N2 preparation instrument which can be interfaced to any commercial continuous flow isotope ratio mass spectrometer (CF-IRMS). The N2 prep unit has gas purification steps, a copper based reduction furnace, and allows the analysis of small gas injection volumes (4 μL) for 15N-N2 analysis. For the analysis of N2O, an automated Tracegas Pre-concentrator (Isoprime Ltd) coupled to an IRMS was used to measure the 15N-N2O (4 mL gas injection volume). Consequently, the coefficient of variation for the determination of isotope ratios for N2 in air and in standard N2O (0.5 ppm) was better than 0.5 %. The 15N Gas-Flux method was adapted for application in natural and semi-natural land use types (peatlands, forests and grasslands) by lowering the 15N tracer application rate to 0.04-0.5 kg 15N ha-1. For our chamber design (volume / surface = 8:1) and a 20 h incubation period, the minimum detectable flux rates were 4 μg N m-2 h-1 and 0.2 ng N m-2 h-1 for the N2 and N2O fluxes respectively. The N2 flux ranged between 2.4 and 416.6 μg N m-2 h-1, and the grassland soils showed on average 3 and 14 times higher denitrification rates than the woodland and organic soils respectively. The N2O flux was on average 20 to 200 times lower than the N2 flux, while the denitrification product ratio (N2O/N2 + N2O) was low, ranging between 0.03 and 13 %. Total denitrification rates measured by the acetylene inhibition technique under the same field conditions

  11. Application of the 15N-Gas Flux method for measuring in situ N2 and N2O fluxes due to denitrification in natural and semi-natural terrestrial ecosystems and comparison with the acetylene inhibition technique

    Directory of Open Access Journals (Sweden)

    F. Sgouridis

    2015-08-01

    Full Text Available Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. 15N tracer approaches can provide in situ measurements of both N2 and N2O simultaneously, but their use has been limited to fertilised agro-ecosystems due to the need for large 15N additions in order to detect 15N2 production against the high atmospheric N2. For 15N-N2 analyses, we have used an "in house" laboratory designed and manufactured N2 preparation instrument which can be interfaced to any commercial continuous flow isotope ratio mass spectrometer (CF-IRMS. The N2 prep unit has gas purification steps, a copper based reduction furnace, and allows the analysis of small gas injection volumes (4 μL for 15N-N2 analysis. For the analysis of N2O, an automated Tracegas Pre-concentrator (Isoprime Ltd coupled to an IRMS was used to measure the 15N-N2O (4 mL gas injection volume. Consequently, the coefficient of variation for the determination of isotope ratios for N2 in air and in standard N2O (0.5 ppm was better than 0.5 %. The 15N Gas-Flux method was adapted for application in natural and semi-natural land use types (peatlands, forests and grasslands by lowering the 15N tracer application rate to 0.04–0.5 kg 15N ha−1. For our chamber design (volume / surface = 8:1 and a 20 h incubation period, the minimum detectable flux rates were 4 μg N m−2 h−1 and 0.2 ng N m−2 h−1 for the N2 and N2O fluxes respectively. The N2 flux ranged between 2.4 and 416.6 μg N m−2 h−1, and the grassland soils showed on average 3 and 14 times higher denitrification rates than the woodland and organic soils respectively. The N2O flux was on average 20 to 200 times lower than the N2 flux, while the denitrification product ratio (N2O/N2 + N2O was low, ranging between 0.03 and 13 %. Total denitrification rates measured by the acetylene inhibition technique

  12. Revisiting software ecosystems research

    DEFF Research Database (Denmark)

    Manikas, Konstantinos

    2016-01-01

    ‘Software ecosystems’ is argued to first appear as a concept more than 10 years ago and software ecosystem research started to take off in 2010. We conduct a systematic literature study, based on the most extensive literature review in the field up to date, with two primarily aims: (a) to provide...... an updated overview of the field and (b) to document evolution in the field. In total, we analyze 231 papers from 2007 until 2014 and provide an overview of the research in software ecosystems. Our analysis reveals a field that is rapidly growing both in volume and empirical focus while becoming more mature...... from evolving. We propose means for future research and the community to address them. Finally, our analysis shapes the view of the field having evolved outside the existing definitions of software ecosystems and thus propose the update of the definition of software ecosystems....

  13. Chinese Ecosystem Research Network

    Institute of Scientific and Technical Information of China (English)

    Huang Tieqing; Liu Jian; Chen Panqin; Fu Bojie

    2002-01-01

    The article analyzes the development of the Chinese Ecosystem Research Network, and its mission, mandate, and management mechanisms, with examples of research, demonstration and consultation for policy-setting.

  14. Formation of Service Ecosystems

    DEFF Research Database (Denmark)

    Jonas, Julia M.; Sörhammar, David; Satzger, Gerhard

    Purpose: Researchers in several different academic disciplines (such as marketing, information systems, and organization) have focused on investigating service and business ecosystems (e.g. Lusch and Nambisan, 2015; Gawer and Cusumano, 2014; Kude et al. 2012). We reviewed 69 papers in service...... – i.e. the “birth phase” (Moore, 2009) of a service ecosystem. This paper, therefore, aims to explore how the somewhat “magic” processes of service ecosystem formation that are being taken for granted actually occur. Methodology/Approach: Building on a review of core elements in the definitions...... proposition; a value proposition (e.g., a business opportunity or a business idea) may form the starting point for actors to collaborate and integrate resources in order realize the value proposition. The initiator of a service ecosystem could for example be an actor (Mark Zuckerberg), resources (website...

  15. Total Ecosystem Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Total ecosystem carbon includes above- and below-ground live plant components (such as leaf, branch, stem and root), dead biomass (such as standing dead wood, down...

  16. Potential for Hybrid Poplar Riparian Buffers to Provide Ecosystem Services in Three Watersheds with Contrasting Agricultural Land Use

    Directory of Open Access Journals (Sweden)

    Julien Fortier

    2016-02-01

    Full Text Available In temperate agricultural watersheds, the rehabilitation of tree vegetation in degraded riparian zones can provide many ecosystem services. This study evaluated ecosystem service provision potential following the conversion of non-managed herbaceous buffers to hybrid poplar (Populus spp. buffers in three watersheds (555–771 km2 of southern Québec (Canada, with contrasting agricultural land uses. To extrapolate services at the watershed level, total stream length where hybrid poplars could be established was calculated using GIS data from hydrological and land cover maps. After nine years, a 100% replacement of herbaceous buffers by hybrid poplar buffers along farm streams could lead to the production of 5280–76,151 tons of whole tree (stems + branches biomass, which could heat 0.5–6.5 ha of greenhouses for nine years, with the potential of displacing 2–29 million litres of fuel oil. Alternatively, the production of 3887–56,135 tons of stem biomass (fuelwood could heat 55–794 new farmhouses or 40–577 old farmhouses for nine years. Producing fuelwood in buffers rather than in farm woodlots could create forest conservation opportunities on 300–4553 ha. Replacing all herbaceous buffers by poplar buffers could provide potential storage of 2984–42,132 t C, 29–442 t N and 3–56 t P in plant biomass, if woody biomass is not harvested. The greatest potential for services provision was in the Pike River watershed where agriculture is the dominant land use. A review of the potential services of poplar buffers is made, and guidelines for managing services and disservices are provided.

  17. Thermal Remote Sensing and the Thermodynamics of Ecosystem Development

    Science.gov (United States)

    Luvall, Jeffrey C.; Rickman, Doug.; Fraser, Roydon F.

    2013-01-01

    Thermal remote sensing can provide environmental measuring tools with capabilities for measuring ecosystem development and integrity. Recent advances in applying principles of nonequilibrium thermodynamics to ecology provide fundamental insights into energy partitioning in ecosystems. Ecosystems are nonequilibrium systems, open to material and energy flows, which grow and develop structures and processes to increase energy degradation. More developed terrestrial ecosystems will be more effective at dissipating the solar gradient (degrading its exergy content) and can be measured by the effective surface temperature of the ecosystem on a landscape scale. Ecosystems are viewed as open thermodynamic systems with a large gradient impressed on them by the exergy flux from the sun. Ecosystems, according to the restated second law, develop in ways that systematically increases their ability to degrade the incoming solar exergy, hence negating it's ability to set up even larger gradients. Thus it should be expected that more mature ecosystems degrade the exergy they capture more completely than a less developed ecosystem. The degree to which incoming solar exergy is degraded is a function of the surface temperature of the ecosystem. If a group of ecosystems receives the same amount of incoming radiation, we would expect that the most mature ecosystem would reradiate its energy at the lowest quality level and thus would have the lowest surface temperature (coldest black body temperature). Initial development work was done using NASA's airborne Thermal Infrared Multispectral Scanner (TIMS) followed by the use of a multispectral visible and thermal scanner- Airborne Thermal and Land Applications Sensor (ATLAS). Luvall and his coworkers have documented ecosystem energy budgets, including tropical forests, midlatitude varied ecosystems, and semiarid ecosystems. These data show that under similar environmental conditions (air temperature, relative humidity, winds, and solar

  18. Towards an Ecosystem Approach to Cheese Microbiology.

    Science.gov (United States)

    Wolfe, Benjamin E; Dutton, Rachel J

    2013-10-01

    Cheese is an ideal environment to serve as a model for the behavior of microbes in complex communities and at the same time allow detailed genetic analysis. Linking organisms, and their genes, to their role in the environment becomes possible in the case of cheese since cheese microbial communities have been "in culture" for thousands of years, with the knowledge of how to grow these organisms passed down by generations of cheesemakers. Recent reviews have described several emerging approaches to link molecular systems biology to ecosystem-scale processes, known as ecosystems biology. These approaches integrate massive datasets now available through high-throughput sequencing technologies with measurements of ecosystem properties. High-throughput datasets uncover the "parts list" (e.g., the species and all the genes within each species) of an ecosystem as well as the molecular basis of interactions within this parts list. Novel computational frameworks make it possible to link species and their interactions to ecosystem properties. Applying these approaches across multiple temporal and spatial scales makes it possible to understand how changes in the parts lists over space and time lead to changes in ecosystems processes. By manipulating the species present within model systems, we can test hypotheses related to the role of microbes in ecosystem function. Due to the tractability of cheese microbial communities, we have the opportunity to use an ecosystems biology approach from the scale of individual microbial cells within a cheese to replicated cheese microbial communities across continents. Using cheese as a model microbial ecosystem can provide a way to answer important questions concerning the form, function, and evolution of microbial communities.

  19. Hydromorphological restoration stimulates river ecosystem metabolism

    Science.gov (United States)

    Kupilas, Benjamin; Hering, Daniel; Lorenz, Armin W.; Knuth, Christoph; Gücker, Björn

    2017-04-01

    Both ecosystem structure and functioning determine ecosystem status and are important for the provision of goods and services to society. However, there is a paucity of research that couples functional measures with assessments of ecosystem structure. In mid-sized and large rivers, effects of restoration on key ecosystem processes, such as ecosystem metabolism, have rarely been addressed and remain poorly understood. We compared three reaches of the third-order, gravel-bed river Ruhr in Germany: two reaches restored with moderate (R1) and substantial effort (R2) and one upstream degraded reach (D). Hydromorphology, habitat composition, and hydrodynamics were assessed. We estimated gross primary production (GPP) and ecosystem respiration (ER) using the one-station open-channel diel dissolved oxygen change method over a 50-day period at the end of each reach. Moreover, we estimated metabolic rates of the combined restored reaches (R1 + R2) using the two-station open-channel method. Values for hydromorphological variables increased with restoration intensity (D macrophyte cover of total wetted area was highest in R2 and lowest in R1, with intermediate values in D. Station R2 had higher average GPP and ER than R1 and D. The combined restored reaches R1 + R2 also exhibited higher GPP and ER than the degraded upstream river (station D). Restoration increased river autotrophy, as indicated by elevated GPP : ER, and net ecosystem production (NEP) of restored reaches. Temporal patterns of ER closely mirrored those of GPP, pointing to the importance of autochthonous production for ecosystem functioning. In conclusion, high reach-scale restoration effort had considerable effects on river hydrodynamics and ecosystem functioning, which were mainly related to massive stands of macrophytes. High rates of metabolism and the occurrence of dense macrophyte stands may increase the assimilation of dissolved nutrients and the sedimentation of particulate nutrients, thereby positively

  20. Measurement of ecotone width between agro-ecosystem and forest ecosystems after Grain for Green Program%退耕还林工程影响下农林生态系统生态交错带的宽度测定

    Institute of Scientific and Technical Information of China (English)

    王婷; 欧晓昆; 张志明; 柳小康; 王丽; 孙振华; 何彪; 李峰

    2012-01-01

    生态交错带宽度的测定是定量研究其生态过程的基础,研究利用移动分割窗技术,对退耕还林工程影响下的山地农业生态系统和森林生态系统间的生态交错带宽度进行测定.首先以对生态交错带生物多样性分布趋势有较好体现的4个多样性指数(物种丰富度、Cody指数、群落相异性系数(βJ和βS))和能体现群落本质特征的重要值为指标,取平方欧氏距离(SED)和Bray-Curtis系数(PD)为距离系数,采用移动分割窗技术分析比较.结果表明,物种丰富度,群落相异性系数βJ和βS曲线趋势具有很好的重合性,同质区间也体现得较为明显,说明这3个指标生态学意义明显,有较高的实用价值;与PD相比,SED函数划分的结果要好.然后选取物种丰富度、群落相异性系数βJ和βS作为指标以及SED作为距离系数对交错带的宽度进行测定.撂荒地-云南松林交错带位置约在样带序列25~36 m处,宽度为9 m,属于急变型交错带.%To measure the eco-tone width is fundamental to the quantitative study on the ecological processes of eco-tone.In this study,Moving Split-Window Technique(MSWT) was used to measure the eco-tone width between mountain agro-ecosystem and forest ecosystem.Four indices(Species richness,Cody,Dissimilarity coefficient and Important value) had been selected,which could reflect the change of species biodiversity in eco-tone transect gradients.In addition,Squared Euclidean distance(SED) was better than Bray-Curtis percent dissimilarity(PD) for quantifying the change of species biodiversity in the eco-tone of agricultural-forest ecosystem.The results showed that the species richness was consistent with issimilarity coefficients in the eco-tone transect.It was also indicated that the width of eco-tone of agricultural-forest ecosystems was a sharp type which spanned about 9 m.

  1. Predicting Ecosystem-scale CO2 Fluxes and Vegetation Biophysical Parameters of a Subalpine Grassland with Continuous Canopy Hyperspectral Reflectance Measurements.

    Science.gov (United States)

    Sakowska, K.; Vescovo, L.; Marcolla, B.; Cavagna, M.; Zampedri, R.; Gianelle, D.

    2015-12-01

    in grassland ecosystem and further upscaling of the observations.

  2. Relationship between the herbaceous and woody vegetation caracteristics and biological soil crusts distribution in fallow and rangeland across a latitudinal gradient in Sahelian Western Niger

    Science.gov (United States)

    Malam Issa, O.; Hiernaux, P.; Kalilou, A.; Rajot, J. L.; Languille, J.

    2012-04-01

    Biological soil crusts (BSC) are common soil feature in the Sahel, in Western Niger. They occur in association with various types of physical soil crusts in fallow, rangeland and 'tiger bush' biomes (landscape with a typical pattern consisting of alternating dense thicket bands composed of shrubs and small trees, and bare soil bands). Despite their widespread occurrence, little research has focussed on the spatial extent of microbiotic soil crusts at regional scale in Sahel. Moreover, little is known about the interrelations between the occurrence of those crusts and the characteristics of the vegetation. In this paper, field data on the distribution of biological soil crusts and some characteristics (cover, composition, mass) of herbaceous and woody vegetation co-occurring in fallows and rangelands are presented and analysed. The study was performed in ten sites selected in Western Niger along a south-north climatic gradient between 650 to 300 mm of annual rainfall. The soil surfaces features, specifically physical and biological soil crusts, were surveyed twice in july-october 2009 and October-november 2011. The second survey combined the assessment of soil surfaces features with systematic observations of vegetation. Herbaceous cover, mass and species composition were assessed by stratified sampling along a 200 meter axis. PCQ distance method was used to characterise the density, cover and species composition of the woody plant population. The extends of BSC observed in the 10 sites in 2011 are in the same order as those observed in 2009, i.e. ranging between 4 and 59% in 2009 vs 1.5 and 48 % in 2011. The results showed a significant increase of BSC coverage with increasing annual rainfall towards the south of the gradient. The actual cover of herbaceous vegetation, taking the extends of bare soil patches in account, averages 14.2 % over the different sites. Similarly to BSC repartition, a slight increase of herbaceous cover is observed from the northern dryer

  3. Comparison of ecosystem water flux measured with the Eddy covariance- and the direct xylem sap flux method in a mountainous forest

    Energy Technology Data Exchange (ETDEWEB)

    Stefanicki, G.; Geissbuehler, P.; Siegwolf, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The Eddy covariance technique allows to measure different components of turbulent air fluxes, including the flow of water vapour. Sap flux measurements determine directly the water flow in tree stems. We compared the water flux just above the crowns of trees in a forest by the technique of Eddy covariance and the water flux by the xylem sap flux method. These two completely different approaches showed a good qualitative correspondence. The correlation coefficient is 0.8. With an estimation of the crown diameter of the measured tree we also find a very good quantitative agreement. (author) 3 figs., 5 refs.

  4. Advances in research of function and valuation of ecosystem services

    Institute of Scientific and Technical Information of China (English)

    Li Liu; Qi Feng

    2015-01-01

    It is widely accepted that there is an economic progress beyond the Gross Domestic Product (GDP), while global GDP has increased more than three-fold since 1950, whereas ecosystems have been largely occupied and depleted. Since the 1990s, emphasis has focused on function and valuation of ecosystem services, which is rarely treated as a market issue. This paper reviews recent developments on measures to evaluate and assess ecosystem services, while elucidating the function of ecosystem services. On the one hand, functions of ecosystem services are subdivided into several items such as gas reg-ulation, water regulation, soil and nutrient recycling. Also, there exist intellectually guided functions of ecosystem services, such as culture and recreation. On the other hand, ecosystems can be viewed as a supplier in the trade between human beings and natural resources such that all resources can be labeled and quantified.

  5. A Two-Step Strategy for Developing Cultivated Pastures in China that Offer the Advantages of Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Haibin Chen

    2016-04-01

    Full Text Available Based on a site experiment on a typical steppe of Inner Mongolia, the short term effects on aboveground biomass, soil water content, soil organic carbon, and soil total nitrogen of four cultivated pastures (CPs with different compositions of herbaceous species were examined and compared to those of adjacent, natural grassland (NG enclosed simultaneously. All CPs produced significantly higher aboveground biomass than did the NG after two years of establishment, and the mixed culture of Agropyron cristatum (A. cristatum and Medicago sativa (M. sativa produced the highest (312.39% higher than the NG. Without irrigation, soil water content in the 10–20 cm soil layer was also found to be significantly higher in the CPs than in the NG, especially for the mixed cultures of A. cristatum and M. sativa, A. cristatum, M. sativa and Lolium perenne (L. perenne, by 184.25% and 125.97%, respectively. The improvements in soil organic carbon and soil total nitrogen in CPs were less obvious and mixed, with different species compositions showing significant increases at different depths. The experimental results suggested that, with carefully selected species compositions and proper farming measures, CPs could have a positive effect on some of the pathways that generate ecosystem services, at least in the short term. We also analyzed the underlying institutional and socioeconomic causes of China’s underdevelopment of CPs, and proposed a two-step development strategy. The first is to promote rain-fed CPs on small-hold farms, which require relatively low inputs in fertilizers and labor. The second is to promote large-scale operations, which will require significantly more inputs in land, irrigation, fertilizers, and machinery.

  6. Response diversity determines the resilience of ecosystems to environmental change.

    Science.gov (United States)

    Mori, Akira S; Furukawa, Takuya; Sasaki, Takehiro

    2013-05-01

    A growing body of evidence highlights the importance of biodiversity for ecosystem stability and the maintenance of optimal ecosystem functionality. Conservation measures are thus essential to safeguard the ecosystem services that biodiversity provides and human society needs. Current anthropogenic threats may lead to detrimental (and perhaps irreversible) ecosystem degradation, providing strong motivation to evaluate the response of ecological communities to various anthropogenic pressures. In particular, ecosystem functions that sustain key ecosystem services should be identified and prioritized for conservation action. Traditional diversity measures (e.g. 'species richness') may not adequately capture the aspects of biodiversity most relevant to ecosystem stability and functionality, but several new concepts may be more appropriate. These include 'response diversity', describing the variation of responses to environmental change among species of a particular community. Response diversity may also be a key determinant of ecosystem resilience in the face of anthropogenic pressures and environmental uncertainty. However, current understanding of response diversity is poor, and we see an urgent need to disentangle the conceptual strands that pervade studies of the relationship between biodiversity and ecosystem functioning. Our review clarifies the links between response diversity and the maintenance of ecosystem functionality by focusing on the insurance hypothesis of biodiversity and the concept of functional redundancy. We provide a conceptual model to describe how loss of response diversity may cause ecosystem degradation through decreased ecosystem resilience. We explicitly explain how response diversity contributes to functional compensation and to spatio-temporal complementarity among species, leading to long-term maintenance of ecosystem multifunctionality. Recent quantitative studies suggest that traditional diversity measures may often be uncoupled from

  7. 三峡工程对水环境与水生态的影响及保护对策%Impacts of Three Gorges Project on water environment and aquatic ecosystem and protective measures

    Institute of Scientific and Technical Information of China (English)

    邹家祥; 翟红娟

    2016-01-01

    介绍三峡工程水环境与水生态现状,分析三峡工程对库区及坝下水文情势、水质、库区及支流富营养化等水环境的影响,以及工程运行对水生态系统、饵料生物、鱼类及珍稀水生动物等水生态的影响,提出优化水库调度、加强城镇生活污水处理、工业废水防治、农村面源治理、饮用水源地保护等水环境保护对策,以及开展栖息地保护、物种保护、人工增殖放流、生态调度等水生生态保护对策。%This paper introduces the water environmental and aquatic ecological status of the Three Gorges Project. The impacts of the project on the aquatic environment, involving hydrological regimes, water quality, reservoir eutrophication, and water blooms in the tributaries, are analyzed. The project ’ s impacts on aquatic ecology, including the aquatic ecosystem, food organisms, fish species, and rare aquatic animals, are also analyzed. Several measures are proposed to protect the water environment, including optimization of reservoir regulation, urban sewage treatment, industrial waste water control, rural non-point source pollution control, and drinking water source protection. For the protection of the aquatic ecosystem, some measures are put forward, including habitat conservation, species conservation, artificial enhancement and release of fish, and ecological reservoir regulation.

  8. Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model.

    Science.gov (United States)

    Harfoot, Michael B J; Newbold, Tim; Tittensor, Derek P; Emmott, Stephen; Hutton, Jon; Lyutsarev, Vassily; Smith, Matthew J; Scharlemann, Jörn P W; Purves, Drew W

    2014-04-01

    Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures.

  9. Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model.

    Directory of Open Access Journals (Sweden)

    Michael B J Harfoot

    2014-04-01

    Full Text Available Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude across the globe led to emergent properties at individual (e.g., growth rate, community (e.g., biomass turnover rates, ecosystem (e.g., trophic pyramids, and macroecological scales (e.g., global patterns of trophic structure that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures.

  10. Effect of A Nitrogen-Fixing Actinorhizal Shrub on Herbaceous Vegetation in A Mixed Conifer Forest of Central Himalaya

    Directory of Open Access Journals (Sweden)

    Kiran Bargali

    2015-12-01

    Full Text Available In this study, we examined the effect of a nitrogen-fixing shrub Coriaria nepalensis Wall on herb species composition, diversity and biomass. The effect was measured in terms of species richness, diversity and biomass of herb species in three sites varying in Coriaria density viz. site 1 (low Coriaria density; 20 ha-1, site-2 (medium Coriaria density; 120 ha-1 and site-3 (high Coriaria density 190 ha-1. Species richness was minimum at Site-1 (16 species, and maximum at site-2 (27 species. G. aparine dominated site-1 and Arthraxon sp dominated site-2 and 3. The individual herb density ranged between 0.40 - 42.40 m-2, and total herb density ranged between 138- 170.4 m-2 and was maximum at site-2. Value for species richness (27 and Shannon Index (3.72 was highest for medium Coriaria density site and lowest for low Coriaria density site. Simpson Index ranged between 0.11 and 0.14 and was lowest for site-2(medium Coriaria density indicating that at this the dominance was shared by many species. Along the gradient of Coriaria density, maximum biomass was recorded at site-3 with highest Coriaria density and lowest at site-2 with medium Coriaria density. This may be due to the symbiotic nitrogen fixing ability of Coriaria that improve the habitat quality. The facilitative effect of C. nepalensis in terms of soil amelioration and herb growth can be used to regenerate degraded forest ecosystems.

  11. The Amazon Tall Tower Observatory (ATTO in the remote Amazon Basin: overview of first results from ecosystem ecology, meteorology, trace gas, and aerosol measurements

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2015-04-01

    Full Text Available The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It already has been changed significantly by human activities, and more pervasive change is expected to occur in the next decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at 5 to 8 different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity. Aerosol optical, microphysical, and chemical measurements are made above the canopy as well as in the canopy space. They include light scattering and absorption, aerosol fluorescence, number and volume size distributions, chemical

  12. The concurrent use of novel soil surface microclimate measurements to evaluate CO2 pulses in biocrusted interspaces in a cool desert ecosystem

    Science.gov (United States)

    Tucker, Colin; McHugh, Theresa A.; Howell, Armin; Gill, Richard; Weber, Bettina; Belnap, Jayne; Grote, Ed; Reed, Sasha C.

    2017-01-01

    Carbon cycling associated with biological soil crusts, which occupy interspaces between vascular plants in drylands globally, may be an important part of the coupled climate-carbon cycle of the Earth system. A major challenge to understanding CO2 fluxes in these systems is that much of the biotic and biogeochemical activity occurs in the upper few mm of the soil surface layer (i.e., the ‘mantle of fertility’), which exhibits highly dynamic and difficult to measure temperature and moisture fluctuations. Here, we report a multi-sensor approach to simultaneously measuring temperature and moisture of this biocrust surface layer (0–2 mm), and the deeper soil profile, concurrent with automated measurement of surface soil CO2effluxes. Our results illuminate robust relationships between biocrust water content and field CO2 pulses that have previously been difficult to detect and explain. All observed CO2 pulses over the measurement period corresponded to surface wetting events, including when the wetting events did not penetrate into the soil below the biocrust layer (0–2 mm). The variability of temperature and moisture of the biocrust surface layer was much greater than even in the 0–5 cm layer of the soil beneath the biocrust, or deeper in the soil profile. We therefore suggest that coupling surface measurements of biocrust moisture and temperature to automated CO2flux measurements may greatly improve our understanding of the climatic sensitivity of carbon cycling in biocrusted interspaces in our study region, and that this method may be globally relevant and applicable.

  13. Efficiency of natural self-purification of ecosystems vs. countermeasures applied at the East-Ural Radioactive Trace (EURT)

    Science.gov (United States)

    Molchanova, I.; Pozolotina, V.; Mikhailovskaya, L.; Antonova, E.

    2012-04-01

    accumulation of the radionuclides within bank area of the lakes. Analysis of the radionuclides depth distribution in the soil profiles across the watershed area showed about 80-87% of Sr-90 and Cs-137 in account to their total contents are retained in the upper humus layer (0-30 cm). The radionuclides are distributed more or less evenly in the soils of accumulative plots of landscape. Some countermeasures were taken around the EURT's territory in order to create relatively safe conditions for human habitation, to reduce the background radiation and intake of the radionuclides in the herbaceous plants. One of them is undercutting contaminated layer for a depth of the soil profile. The success of this measure was provided by heavy-loam of the soil texture. Last research of these plots has shown the maximum contamination is still shifted out of the root layer. As a result the first link of the food chain presented by herbaceous vegetation showed significantly lower level of the radionuclides accumulation in comparison to the non reclaimed areas. Another countermeasure connected with removal and disposal of the soil surface layer was used in the resettled villages. In this case, the stock of radionuclides in the soil was shown to be twice lower comparing to the contiguous non reclaimed areas. This fact particularly indicates positive changes occurred in ecosystems around the resettled villages. Thus, the countermeasures developed around the EURT should be considered as successful and effective for achievement of the main task focused on complex improvement of the radiation conditions across the EURT. These countermeasures will be effective in other contaminated areas having the similar characteristics of the soils, landscapes and climate.

  14. Characteristics of the herbaceous layer in preferred grazing areas of six herbivore species in the south-eastern Kruger National Park

    Directory of Open Access Journals (Sweden)

    J.J. Wentzel

    1991-09-01

    Full Text Available The phytomass and species composition of the herbaceous layer in preferred grazing areas of zebra Equus burchellii, buffalo Syncerus caffer, waterbuck Kobus ellipsiprymnus, blue wildebeest Connochaetes taurinus, impala Aepyceros melampus and warthog Phacochoerusaethiopicus were investigated within the south-eastern portion of the Kruger National Park. The percentage frequency of herbaceous plants in Decreaser and Increaser categories, as determined by their reaction to different intensities of grazing, was established. The preferred grazing areas of the relevant herbivore species were compared in terms of phytomass, contribution of the Decreaser and Increaser categories, veld condition and degree of utilisation. The grazing areas of buffalo and zebra showed less utilisation than those of the other herbivore species. Warthog and impala were associated with over-utilised areas. It is clear that localised over-utilisation is an integral part of the natural grazing mosaic and should be managed as such in large African conservation areas.

  15. Accounting for ecosystem assets using remote sensing in the Colombian Orinoco River basin lowlands

    Science.gov (United States)

    Vargas, Leonardo; Hein, Lars; Remme, Roy P.

    2016-10-01

    In many parts of the world, ecosystems change compromises the supply of ecosystem services (ES). Better ecosystem management requires detailed and structured information. Ecosystem accounting has been developed as an information system for ecosystems, using concepts and valuation approaches that are aligned with the System of National Accounts (SNA). The SNA is used to store and analyse economic data, and the alignment of ecosystem accounts with the SNA facilitates the integrated analysis of economic and ecological aspects of ecosystem use. Ecosystem accounting requires detailed spatial information at aggregated scales. The objective of this paper is to explore how remote sensing images can be used to analyse ecosystems using an accounting approach in the Orinoco river basin. We assessed ecosystem assets in terms of extent, condition and capacity to supply ES. We focus on four specific ES: grasslands grazed by cattle, timber and oil palm harvest, and carbon sequestration. We link ES with six ecosystem assets; savannahs, woody grasslands, mixed agro-ecosystems, very dense forests, dense forest and oil palm plantations. We used remote sensing vegetation, surface temperature and productivity indexes to measure ecosystem assets. We found that remote sensing is a powerful tool to estimate ecosystem extent. The enhanced vegetation index can be used to assess ecosystems condition, and net primary productivity can be used for the assessment of ecosystem assets capacity to supply ES. Integrating remote sensing and ecological information facilitates efficient monitoring of ecosystem assets, in particular in data poor contexts.

  16. Burned Area Detection in the Ecosystem Transition Zone Using MODIS Data%利用MODIS影像提取火烧迹地方法的研究

    Institute of Scientific and Technical Information of China (English)

    肖潇; 冯险峰; 孙庆龄

    2016-01-01

    火烧迹地监测不仅可以反映火灾对生态系统的影响情况及损失信息,还能为全球碳循环研究提供重要的数据支持.本文利用MODIS地表反射率产品(MOD09A1)的近红外和短波红外波段构建的归一化燃烧率指数(NBR),计算前后2期影像的NBR差值,并在光谱指数差分法的基础上,结合MODIS植被数据产品(MOD44B)提供的植被覆盖度信息,设置规则提取火烧迹地.本文选择西伯利亚地区东南部的林地、草地、农田等不同生态系统的交界地带作为实验区,利用本文算法提取该区域的火烧迹地.实验结果表明:(1)本文算法的火烧迹地提取效果较好,优于MODIS火烧迹地产品(MCD45A1),kappa系数由0.70提高到0.75;(2)利用林木覆盖度、草本覆盖度数据,可以减少误判,提高火烧迹地提取的精度,kappa系数分别由0.69、0.73都提高到0.75.%Fires belong to one of the main disturbance factors and play an important role in various ecosystems. Burned area detec-tion not only indicates the impact of fires on ecosystems, but also provides a scientific support for the global carbon cycle studies. Traditional burned scar area detection approach mainly depends on ground survey and measurements, which still has several de-fects, such as the heavy workload, high cost, low efficiency, and poor timeliness etc. By applying remote sensing technology to map the burned area can produce burn scar information with greater spatial and temporal scale and effectively avoid the above-men-tioned problems. Currently, many methods aiming to map the burned area on remote sensing images have been developed, and vari-ous global burned area products which provide the consistent assessments of fire activity at the global scale are also available;how-ever, the efficiency of their performances differs within various ecosystems. In this study, we developed an algorithm to map the burned scar area in an ecosystem transition zone by using the Moderate

  17. Plasmodesmatal Dynamics in Both Woody Poplar and Herbaceous Winter Wheat Under Controlled Short Day and in Field Winter Period

    Institute of Scientific and Technical Information of China (English)

    JIANLing-Cheng; WANGHong

    2004-01-01

    Electron microscopic observation revealed that poplar (Populus deltoides Marsh.) and winterwheat ( Triticum aestivum L. cv. Seward 80004) plasmodesmatal structures significantly changed undershort day (SD, 8 h light) and in winter period, and such changes differed also noticeably between these twowoody and herbaceous plants. Under long day (LD, 16 h light), many plasmodesmata with strong stainappeared in the cell wall of both poplar apical buds and winter wheat young leaf tissues, and connections ofcytoplasmic endoplasmic reticulum (ER) with the ER in some plasmodesmata were observed. In addition,the typical “neck type” plasmodesmata were observed in winter wheat young leaf tissues, and their centraldesmotubules (appressed-ER) could be clearly identified. Under SD, many poplar plasmodesmata showedonly a partial structure in the cell wall and appeared to be discontinued; some plasmodesmata swelled in themid-wall, forming the cavity, and no appressed-ER appeared, in winter wheat, however, no noticeablealterations of plasmodesmata occurred, and the plasmodesmatal structure essentially remained the sameas it was under LD. In winter period, poplar plasmodesmata had a similar morphology as those observedunder SD, however, winter wheat manifested at least two types of significant plasmodesmatal alterations:one plugged by electron-dense materials and the other of reduced neck region compared to those underLD. The above dynamic difference of the two species plasmodesmata under SD and winter period revealedthe difference of their dormancy development under those environmental conditions.

  18. Environmental factors influencing soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient in subarctic tundra (Abisko, Sweden).

    Science.gov (United States)

    Tsyganov, Andrey N; Milbau, Ann; Beyens, Louis

    2013-05-01

    Shifts in community composition of soil protozoa in response to climate change may substantially influence microbial activity and thereby decomposition processes. However, effects of climate and vegetation on soil protozoa remain poorly understood. We studied the distribution of soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient (from below the treeline at 500 m to the mid-alpine region at 900 m a.s.l.) in subarctic tundra. To explain patterns in abundance, species diversity and assemblage composition of testate amoebae, a data set of microclimate and soil chemical characteristics was collected. Both elevation and vegetation influenced the assemblage composition of testate amoebae. The variation was regulated by interactive effects of summer soil moisture, winter soil temperature, soil pH and nitrate ion concentrations. Besides, soil moisture regulated non-linear patterns in species richness across the gradient. This is the first study showing the effects of winter soil temperatures on species composition of soil protozoa. The effects could be explained by specific adaptations of testate amoebae such as frost-resistant cysts allowing them to survive low winter temperatures. We conclude that the microclimate and soil chemical characteristics are the main drivers of changes in protozoan assemblage composition in response to elevation and vegetation.

  19. Diversity and distribution patterns of root-associated fungi on herbaceous plants in alpine meadows of southwestern China.

    Science.gov (United States)

    Gao, Qian; Yang, Zhu L

    2016-01-01

    The diversity of root-associated fungi associated with four ectomycorrhizal herbaceous species, Kobresia capillifolia, Carex parva, Polygonum macrophyllum and Potentilla fallens, collected in three sites of alpine meadows in southwestern China, was estimated based on internal transcribed spacer (ITS) rDNA sequence analysis of root tips. Three hundred seventy-seven fungal sequences sorted to 154 operational taxonomical units (sequence similarity of ≥ 97% across the ITS) were obtained from the four plant species across all three sites. Similar taxa (in GenBank with ≥ 97% similarity) were not found in GenBank and/or UNITE for most of the OTUs. Ectomycorrhiz a made up 64% of the fungi operational taxonomic units (OTUs), endophytes constituted 4% and the other 33% were unidentified root-associated fungi. Fungal OTUs were represented by 57% basidiomycetes and 43% ascomycetes. Inocybe, Tomentella/Thelophora, Sebacina, Hebeloma, Pezizomycotina, Cenococcum geophilum complex, Cortinarius, Lactarius and Helotiales were OTU-rich fungal lineages. Across the sites and host species the root-associated fungal communities generally exhibited low host and site specificity but high host and sampling site preference. Collectively our study revealed noteworthy diversity and endemism of root-associated fungi of alpine plants in this global biodiversity hotspot.

  20. Digital Gene Expression Analysis to Screen Disease Resistance-Relevant Genes from Leaves of Herbaceous Peony (Paeonia lactiflora Pall. Infected by Botrytis cinerea.

    Directory of Open Access Journals (Sweden)

    Saijie Gong

    Full Text Available Herbaceous peony (Paeonia lactiflora Pall. is a well-known traditional flower in China and is widely used for landscaping and garden greening due to its high ornamental value. However, disease spots usually appear after the flowering of the plant and may result in the withering of the plant in severe cases. This study examined the disease incidence in an herbaceous peony field in the Yangzhou region, Jiangsu Province. Based on morphological characteristics and molecular data, the disease in this area was identified as a gray mold caused by Botrytis cinerea. Based on previously obtained transcriptome data, eight libraries generated from two herbaceous peony cultivars 'Zifengyu' and 'Dafugui' with different susceptibilities to the disease were then analyzed using digital gene expression profiling (DGE. Thousands of differentially expressed genes (DEGs were screened by comparing the eight samples, and these genes were annotated using the Gene ontology (GO and Kyoto encyclopedia of genes and genomes (KEGG database. The pathways related to plant-pathogen interaction, secondary metabolism synthesis and antioxidant system were concentrated, and 51, 76, and 13 disease resistance-relevant candidate genes were identified, respectively. The expression patterns of these candidate genes differed between the two cultivars: their expression of the disease-resistant cultivar 'Zifengyu' sharply increased during the early stages of infection, while it was relatively subdued in the disease-sensitive cultivar 'Dafugui'. A selection of ten candidate genes was evaluated by quantitative real-time PCR (qRT-PCR to validate the DGE data. These results revealed the transcriptional changes that took place during the interaction of herbaceous peony with B. cinerea, providing insight into the molecular mechanisms of host resistance to gray mold.

  1. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    Science.gov (United States)

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith Marcoe

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  2. Mapping cultural ecosystem services:

    DEFF Research Database (Denmark)

    Paracchini, Maria Luisa; Zulian, Grazia; Kopperoinen, Leena

    2014-01-01

    is required to address the issue, since by definition cultural services (encompassing physical, intellectual, spiritual interactions with biota) need to be analysed from multiple perspectives (i.e. ecological, social, behavioural). A second reason is the lack of data for large-scale assessments, as detailed......Research on ecosystem services mapping and valuing has increased significantly in recent years. However, compared to provisioning and regulating services, cultural ecosystem services have not yet been fully integrated into operational frameworks. One reason for this is that transdisciplinarity...... surveys are a main source of information. Among cultural ecosystem services, assessment of outdoor recreation can be based on a large pool of literature developed mostly in social and medical science, and landscape and ecology studies. This paper presents a methodology to include recreation...

  3. Nutrient budget in ecosystems

    Science.gov (United States)

    Titlyanova, A. A.

    2007-12-01

    Methods to calculate nutrient budgets in forest and grassland ecosystems are analyzed on the basis of a large number of published materials and original data. New estimates of the belowground production in forest ecosystems with due account for the growth of fine roots are suggested. Nutrient retranslocation from senescent plant tissues to growing plant tissues and nutrient leaching from the forest canopy are discussed. The budgets of major nutrients (N, P, K, and Ca) in tundra, forest, and steppe ecosystems are calculated. Nutrient cycles in two forest ecosystems—a coniferous stand dominated by Picea abies and a broad-leaved stand dominated by Quercus robur—are analyzed in detail. It is shown that the more intensive turnover of nutrients in the oak stand is also characterized by a more closed character of the nutrient cycles.

  4. Evaluation of HOx sources and cycling using measurement-constrained model calculations in a 2-methyl-3-butene-2-ol (MBO and monoterpene (MT dominated ecosystem

    Directory of Open Access Journals (Sweden)

    S. B. Henry

    2013-02-01

    Full Text Available We present a detailed analysis of OH observations from the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-ROCS (Rocky Mountain Organic Carbon Study 2010 field campaign at the Manitou Forest Observatory (MFO, which is a 2-methyl-3-butene-2-ol (MBO and monoterpene (MT dominated forest environment. A comprehensive suite of measurements was used to constrain primary production of OH via ozone photolysis, OH recycling from HO2, and OH chemical loss rates, in order to estimate the steady-state concentration of OH. In addition, the University of Washington Chemical Model (UWCM was used to evaluate the performance of a near-explicit chemical mechanism. The diurnal cycle in OH from the steady-state calculations is in good agreement with measurement. A comparison between the photolytic production rates and the recycling rates from the HO2 + NO reaction shows that recycling rates are ~20 times faster than the photolytic OH production rates from ozone. Thus, we find that direct measurement of the recycling rates and the OH loss rates can provide accurate predictions of OH concentrations. More importantly, we also conclude that a conventional OH recycling pathway (HO2 + NO can explain the observed OH levels in this non-isoprene environment. This is in contrast to observations in isoprene-dominated regions, where investigators have observed significant underestimation of OH and have speculated that unknown sources of OH are responsible. The highly-constrained UWCM calculation under-predicts observed HO2 by as much as a factor of 8. As HO2 maintains oxidation capacity by recycling to OH, UWCM underestimates observed OH by as much as a factor of 4. When the UWCM calculation is constrained by measured HO2, model calculated OH is in better agreement with the observed OH levels. Conversely, constraining the model to observed OH only slightly reduces the model-measurement HO2 discrepancy, implying unknown HO2

  5. Catastrophic shifts in ecosystems

    Science.gov (United States)

    Scheffer, Marten; Carpenter, Steve; Foley, Jonathan A.; Folke, Carl; Walker, Brian

    2001-10-01

    All ecosystems are exposed to gradual changes in climate, nutrient loading, habitat fragmentation or biotic exploitation. Nature is usually assumed to respond to gradual change in a smooth way. However, studies on lakes, coral reefs, oceans, forests and arid lands have shown that smooth change can be interrupted by sudden drastic switches to a contrasting state. Although diverse events can trigger such shifts, recent studies show that a loss of resilience usually paves the way for a switch to an alternative state. This suggests that strategies for sustainable management of such ecosystems should focus on maintaining resilience.

  6. Bioenergetics in ecosystems

    Science.gov (United States)

    Madenjian, Charles P.; Farrell, Anthony P.

    2011-01-01

    A bioenergetics model for a fish can be defined as a quantitative description of the fish’s energy budget. Bioenergetics modeling can be applied to a fish population in a lake, river, or ocean to estimate the annual consumption of food by the fish population; such applications have proved to be useful in managing fisheries. In addition, bioenergetics models have been used to better understand fish growth and consumption in ecosystems, to determine the importance of the role of fish in cycling nutrients within ecosystems, and to identify the important factors regulating contaminant accumulation in fish from lakes, rivers, and oceans.

  7. Assessing the transferability of ecosystem service production estimates and functions

    Science.gov (United States)

    Estimates of ecosystem service (ES) production, and their responses to stressors or policy actions, may be obtained by direct measurement, other empirical studies, or modeling. Direct measurement is costly and often impractical, and thus many studies transfer ES production estim...

  8. The Dynamics of Growing Herbaceous Plants in the Soil Contaminated with Sodium Formiate

    Directory of Open Access Journals (Sweden)

    Agnė Kazlauskienė

    2011-02-01

    Full Text Available Salts are most frequently used for road maintenance in cold seasons in Lithuania. In case the use of salts is mandatory, the proposal is to apply as small amounts as possible following the norms of use. Using alternative de-icing salts and agents, such as formiates is recommended. Formiates can be applied with the aim to reduce road sliperness and as a preventive measure of de-icing road paving. These substances are efficient, environment-friendly and have no corrosive effect. The article presents physicochemical and toxicological characteristics of the above introduced materials.Article in Lithuanian

  9. Integrating est.of ecosystem respiration from eddy covariance towers with automated measures of soil respiration: Exam. the dvlpt. and influence of hysteresis in soil respiratory fluxes along a woody plant gradient 2026

    Science.gov (United States)

    The physiognomic shift in ecosystem structure from a grassland to a woodland may alter the sensitivity of CO2 exchange to variations in growing-season temperatures and precipitation inputs. One large component of ecosystem flux is the efflux of CO2 from the soil (soil respiration, Rsoil), which is ...

  10. Influence of tree species on the herbaceous understory and soil chemical characteristics in a silvopastoral system in semi-arid northeastern Brazil

    Directory of Open Access Journals (Sweden)

    R. S. C. Menezes

    1999-12-01

    Full Text Available Studies from some semi-arid regions of the world have shown the beneficial effect of trees in silvopastoral systems, by promoting the formation of resource islands and increasing the sustainability of the system. No data are available in this respect for tree species of common occurrence in semi-arid Northeastern Brazil. In the present study, conducted in the summer of 1996, three tree species (Zyziphus joazeiro, Spondias tuberosa and Prosopis juliflora: found within Cenchrus ciliaris pastures were selected to evaluate differences on herbaceous understory and soil chemical characteristics between samples taken under the tree canopy and in open grass areas. Transects extending from the tree trunk to open grass areas were established, and soil (0-15 cm and herbaceous understory (standing live biomass in 1 m² plots samples were taken at 0, 25, 50, 100, 150 and 200% of the average canopy radius (average radius was 6.6 ± 0.5, 4.5 ± 0.5, and 5.3 ± 0.8 m for Z. joazeiro, P. juliflora, and S. tuberosa , respectively. Higher levels of soil C, N, P, Ca, Mg, K, and Na were found under the canopies of Z. joazeiro and P. juliflora: trees, as compared to open grass areas. Only soil Mg organic P were higher under the canopies of S. tuberosa trees, as compared to open grass areas. Herbaceous understory biomass was significantly lower under the canopy of S. tuberosa and P. juliflora trees (107 and 96 g m-2, respectively relatively to open grass areas (145 and 194 g m-2. No herbaceous biomass differences were found between Z. joazeiro canopies and open grass areas (107 and 87 g m-2, respectively. Among the three tree species studied, Z. joazeiro was the one that presented the greatest potential for use in a silvopastoral system at the study site, since it had a larger nutrient stock in the soil without negatively affecting herbaceous understory biomass, relatively to open grass areas.

  11. The spatial distribution of exoenzyme activities across the soil micro-landscape, as measured in micro- and macro-aggregates, and ecosystem processes

    DEFF Research Database (Denmark)

    Kim, Haryun; Nunan, Naoise; Dechesne, Arnaud

    2015-01-01

    The spatial ecology of soil microbial communities and their functioning is an understudied aspect of soil microbial ecology. Much of our understanding of the spatial organisation of microbial communities has been obtained at scales that are inappropriate for identifying how microbial functioning...... structure was also measured in soil aggregates. All the EEA exhibited scale-invariant spatial clustering. The extent of spatial clustering varied significantly among EEA, suggesting that microbial communities employ different spatial strategies when foraging for different elements. The dispersed...... of spatial clustering of EEA and the overall intensity of the EEA was identified in the two loamy soils, indicating that the microscale spatial ecology of microbial activity may have a significant impact on biogeochemical cycles. No relationship was found between microbial community structure and EEA...

  12. Allometry and development in herbaceous plants: functional responses of meristem allocation to light and nutrient availability.

    Science.gov (United States)

    Bonser, Stephen P; Aarssen, Lonnie W

    2003-03-01

    We examined the relationship between meristem allocation and plant size for four annual plant species: Arabidopsis thaliana, Arenaria serphyllifolia, Brassica rapa, and Chaenorrhinum minus. Gradients of light and nutrient availability were used to obtain a range of plant sizes for each of these species. Relative allocation to reproductive, inactive, and growth meristems were used to measure reproductive effort, apical dominance, and branching intensity, respectively. We measured allocation to each of these three meristem fates at weekly intervals throughout development and at final developmental stage. At all developmental stages reproductive effort and branching intensity tended to increase with increasing plant size (i.e., due to increasing resource availability) and apical dominance tended to decrease with increasing plant size. We interpret these responses as a strategy for plants to maximize fitness across a range of environments. In addition, significant differences in meristem response among species may be important in defining the range of habitats in which a species can exist and may help explain patterns of species competition and coexistence in habitats with variable resource availability.

  13. Management Strategy Evaluation Applied to Coral Reef Ecosystems in Support of Ecosystem-Based Management.

    Science.gov (United States)

    Weijerman, Mariska; Fulton, Elizabeth A; Brainard, Russell E

    2016-01-01

    Ecosystem modelling is increasingly used to explore ecosystem-level effects of changing environmental conditions and management actions. For coral reefs there has been increasing interest in recent decades in the use of ecosystem models for evaluating the effects of fishing and the efficacy of marine protected areas. However, ecosystem models that integrate physical forcings, biogeochemical and ecological dynamics, and human induced perturbations are still underdeveloped. We applied an ecosystem model (Atlantis) to the coral reef ecosystem of Guam using a suite of management scenarios prioritized in consultation with local resource managers to review the effects of each scenario on performance measures related to the ecosystem, the reef-fish fishery (e.g., fish landings) and coral habitat. Comparing tradeoffs across the selected scenarios showed that each scenario performed best for at least one of the selected performance indicators. The integrated 'full regulation' scenario outperformed other scenarios with four out of the six performance metrics at the cost of reef-fish landings. This model application quantifies the socio-ecological costs and benefits of alternative management scenarios. When the effects of climate change were taken into account, several scenarios performed equally well, but none prevented a collapse in coral biomass over the next few decades assuming a business-as-usual greenhouse gas emissions scenario.

  14. Management Strategy Evaluation Applied to Coral Reef Ecosystems in Support of Ecosystem-Based Management.

    Directory of Open Access Journals (Sweden)

    Mariska Weijerman

    Full Text Available Ecosystem modelling is increasingly used to explore ecosystem-level effects of changing environmental conditions and management actions. For coral reefs there has been increasing interest in recent decades in the use of ecosystem models for evaluating the effects of fishing and the efficacy of marine protected areas. However, ecosystem models that integrate physical forcings, biogeochemical and ecological dynamics, and human induced perturbations are still underdeveloped. We applied an ecosystem model (Atlantis to the coral reef ecosystem of Guam using a suite of management scenarios prioritized in consultation with local resource managers to review the effects of each scenario on performance measures related to the ecosystem, the reef-fish fishery (e.g., fish landings and coral habitat. Comparing tradeoffs across the selected scenarios showed that each scenario performed best for at least one of the selected performance indicators. The integrated 'full regulation' scenario outperformed other scenarios with four out of the six performance metrics at the cost of reef-fish landings. This model application quantifies the socio-ecological costs and benefits of alternative management scenarios. When the effects of climate change were taken into account, several scenarios performed equally well, but none prevented a collapse in coral biomass over the next few decades assuming a business-as-usual greenhouse gas emissions scenario.

  15. Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan.

    Science.gov (United States)

    Li, Longhui; Chen, Xi; van der Tol, Christiaan; Luo, Geping; Su, Zhongbo

    2014-01-01

    Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia.

  16. Governing ecosystem services

    NARCIS (Netherlands)

    Verburg, René; Selnes, Trond; Verweij, Pita

    2016-01-01

    The TEEB approach to the use of ecosystem services has found its way to policy as a means to biodiversity conservation and greening of the economy. In this paper we analysed the uptake of the TEEB approach at national and local levels by applying a framework that revolves around the problem, appr

  17. Shelf-sea ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, J J

    1980-01-01

    An analysis of the food chain dynamics of the Oregon, Alaskan, and New York shelves is made with respect to differences in physical forcing of these ecosystems. The world's shelves are 10% of the area of the ocean, yield 99% of the world's fish catch, and may be a major sink in the global CO/sub 2/ budget.

  18. Environmental Impacts - Coastal Ecosystems

    NARCIS (Netherlands)

    Bakker, J.P.; Baas, Andreas C.W.; Bartholdy, Jesper; Jones, Laurence; Ruessink, B.G.; Temmerman, Stijn; van de Pol, Martijn

    2016-01-01

    This chapter examines the impacts of climate change on the natural coastal ecosystems in the North Sea region. These comprise sandy shores and dunes and salt marshes in estuaries and along the coast. The chapter starts by describing the characteristic geomorphological features of these systems and t

  19. Governance of Ecosystem Services

    NARCIS (Netherlands)

    Primmer, Eeva; Jokinen, Pekka; Blicharska, Malgorzata; Barton, David N.; Bugter, Rob; Potschin, Marion

    2015-01-01

    Biodiversity conservation policies justified with science and intrinsic value arguments have produced disappointing outcomes, and the need for conservation is now being additionally justified with the concept of ecosystem services. However, little, if any empirical attention is paid to ways in wh

  20. Partitioning ecosystems for sustainability.

    Science.gov (United States)

    Murray, Martyn G

    2016-03-01

    Decline in the abundance of renewable natural resources (RNRs) coupled with increasing demands of an expanding human population will greatly intensify competition for Earth's natural resources during this century, yet curiously, analytical approaches to the management of productive ecosystems (ecological theory of wildlife harvesting, tragedy of the commons, green economics, and bioeconomics) give only peripheral attention to the driving influence of competition on resource exploitation. Here, I apply resource competition theory (RCT) to the exploitation of RNRs and derive four general policies in support of their sustainable and equitable use: (1) regulate resource extraction technology to avoid damage to the resource base; (2) increase efficiency of resource use and reduce waste at every step in the resource supply chain and distribution network; (3) partition ecosystems with the harvesting niche as the basic organizing principle for sustainable management of natural resources by multiple users; and (4) increase negative feedback between consumer and resource to bring about long-term sustainable use. A simple policy framework demonstrates how RCT integrates with other elements of sustainability science to better manage productive ecosystems. Several problem areas of RNR management are discussed in the light of RCT, including tragedy of the commons, overharvesting, resource collapse, bycatch, single species quotas, and simplification of ecosystems.

  1. Biocomplexity in Mangrove Ecosystems

    Science.gov (United States)

    Feller, I. C.; Lovelock, C. E.; Berger, U.; McKee, K. L.; Joye, S. B.; Ball, M. C.

    2010-01-01

    Mangroves are an ecological assemblage of trees and shrubs adapted to grow in intertidal environments along tropical coasts. Despite repeated demonstration of their economic and societal value, more than 50% of the world's mangroves have been destroyed, 35% in the past two decades to aquaculture and coastal development, altered hydrology, sea-level rise, and nutrient overenrichment. Variations in the structure and function of mangrove ecosystems have generally been described solely on the basis of a hierarchical classification of the physical characteristics of the intertidal environment, including climate, geomorphology, topography, and hydrology. Here, we use the concept of emergent properties at multiple levels within a hierarchical framework to review how the interplay between specialized adaptations and extreme trait plasticity that characterizes mangroves and intertidal environments gives rise to the biocomplexity that distinguishes mangrove ecosystems. The traits that allow mangroves to tolerate variable salinity, flooding, and nutrient availability influence ecosystem processes and ultimately the services they provide. We conclude that an integrated research strategy using emergent properties in empirical and theoretical studies provides a holistic approach for understanding and managing mangrove ecosystems.

  2. The Aerosol, Clouds and Ecosystem (ACE) Mission

    Science.gov (United States)

    Schoeberl, M.; Remer, L.; Kahn, R.; Starr, D.; Hildebrand, P.; Colarco, P.; Diner, D.; Vane, D.; Im, E.; Behrenfeld, M.; Stephens, G.; Maring, H.; Bontempi, P.; Martins, J. V.

    2008-12-01

    The Aerosol, Clouds and Ecosystem (ACE) Mission is a second tier Decadal Survey mission designed to characterize the role of aerosols in climate forcing, especially their impact on precipitation and cloud formation. ACE also includes ocean biosphere measurements (chlorophyll and dissolved organic materials) which will be greatly improved by simultaneous measurements of aerosols. The nominal ACE payload includes lidar and multiangle spectropolarimetric polarimetric measurements of aerosols, radar measurements of clouds and multi-band spectrometer for the measurement of ocean ecosystems. An enhancement to ACE payload under consideration includes µ-wave radiometer measurements of cloud ice and water outside the nadir path of the radar/lidar beams. This talk will cover ACE instrument and science options, updates on the science team definition activity and science potential.

  3. [Urban ecosystem services: A review].

    Science.gov (United States)

    Mao, Qi-zheng; Huang, Gan-lin; Wu, Jian-guo

    2015-04-01

    Maintaining and improving ecosystem services in urban areas and human well-being are essential for sustainable development and therefore constitute an important topic in urban ecology. Here we reviewed studies on ecosystem services in urban areas. Based on the concept and classification of urban ecosystem services, we summarized characteristics of urban ecosystem services, including the human domination, high demand of ecosystem services in urban areas, spatial heterogeneity and temporal dynamics of ecosystem services supply and demand in urban areas, multi-services of urban green infrastructures, the socio-economic dimension of ecosystem services supply and ecosystem disservices in urban areas. Among different urban ecosystem services, the regulating service and cultural service are particularly indispensable to benefit human health. We pointed out that tradeoffs among different types of ecosystem services mostly occur between supportive service and cultural service, as well as regulating service and cultural service. In particular, we emphasized the relationship between landscape design (i.e. green infrastructure) and ecosystem services supply. Finally, we discussed current gaps to link urban ecosystem services studies to landscape design and management and pointed out several directions for future research in urban ecosystem services.

  4. The United States' Next Generation of Atmospheric Composition and Coastal Ecosystem Measurements: NASA's Geostationary Coastal and Air Pollution Events (GEO-CAPE) Mission

    Science.gov (United States)

    Fishman, J.; Iraci, Laura T.; Al-Saddi, J.; Chance, K.; Chavez, F.; Chin, M.; Coble, P.; Davis, C.; DiGiacomo, P. M.; Edwards, D.; Eldering, A.; Goes, J.; Herman, J.; Hu, C.; Jacob, D. J.; Jordan, C.; Kawa, S. R.; Key, R.; Liu, X.; Lohrenz, S.; Mannino, A.; Natraj, V.; Neil, D.; Neu, J.; Newchurch, M.; Pickering, K.; Salisbury, J.; Sosik, H.; Subramaniam, A.; Tzortziou, M; Wang, J.; Wang, M.

    2012-01-01

    The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission was recommended by the National Research Council's (NRC's) Earth Science Decadal Survey to measure tropospheric trace gases and aerosols and coastal ocean phytoplankton, water quality, and biogeochemistry from geostationary orbit, providing continuous observations within the field of view. To fulfill the mandate and address the challenge put forth by the NRC, two GEO-CAPE Science Working Groups (SWGs), representing the atmospheric composition and ocean color disciplines, have developed realistic science objectives using input drawn from several community workshops. The GEO-CAPE mission will take advantage of this revolutionary advance in temporal frequency for both of these disciplines. Multiple observations per day are required to explore the physical, chemical, and dynamical processes that determine tropospheric composition and air quality over spatial scales ranging from urban to continental, and over temporal scales ranging from diurnal to seasonal. Likewise, high-frequency satellite observations are critical to studying and quantifying biological, chemical, and physical processes within the coastal ocean. These observations are to be achieved from a vantage point near 95deg-100degW, providing a complete view of North America as well as the adjacent oceans. The SWGs have also endorsed the concept of phased implementation using commercial satellites to reduce mission risk and cost. GEO-CAPE will join the global constellation of geostationary atmospheric chemistry and coastal ocean color sensors planned to be in orbit in the 2020 time frame.

  5. Rooting of herbaceous minicuttings of passion fruit/ Enraizamento de miniestacas herbáceas de maracujazeiro amarelo

    Directory of Open Access Journals (Sweden)

    Rudival Faquim

    2007-08-01

    Full Text Available The objective of this work was to evaluate the effect of the basal cut, leaf presence and the treament with a root suspension in the rooting of herbaceous minicuttings of yellow passion fruit. The experiment was realized in a greenhouse using minicuttings with 8 cm of lenght and two nodes, collected from yellow passion fruit seedlings. The longitudinal basal cut in the minicuttings was done until the basal node. The leaves were removed or a half of a single leaf was maintained in the apical node. The minicuttings were treated with a root suspension in water in three concentrations (0, 100 e 200 g L-1. After 58 days, the rooting percentage, the number of roots and the root dry matter produced per minicutting were determined. The entirely randomized experimental design was used in a factorial esqueme (2 x 2 x 3 with three replications. The propagation of the yellow passion fruit by herbaceous minicuttings was viable and the presence of the half of a single leaf in the apical node give a higher production of number and dry matter of roots. The basal cut was only a little favourable to the production of roots and the treatment with a root suspension did not present a benefit to the plant propagation.Este trabalho objetivou avaliar a influência do corte basal, da presença da folha e do tratamento com suspensão de raízes no enraizamento de miniestacas herbáceas de maracujazeiro amarelo. O experimento foi conduzido em casa de vegetação com miniestacas de 8 cm de comprimento e dois nós, obtidas de mudas de maracujazeiro. O corte longitudinal na base das estacas foi feito até o nó basal. Foram retiradas as folhas ou mantida a metade da folha do nó apical. As miniestacas foram tratadas com suspensão de raízes mais água nas concentrações de 0, 100 e 200 g L-1. Após 58 dias, determinou-se a porcentagem de estacas enraizadas, o número de raízes emitidas e a massa seca de raízes por estaca. O delineamento experimental utilizado foi o

  6. Does Biodiversity-Ecosystem Function Literature Neglect Tropical Ecosystems?

    Science.gov (United States)

    Clarke, David A; York, Paul H; Rasheed, Michael A; Northfield, Tobin D

    2017-05-01

    Current evidence suggests that there is a positive relationship between biodiversity and ecosystem functioning, but few studies have addressed tropical ecosystems where the highest levels of biodiversity occur. We develop two hypotheses for the implications of generalizing from temperate studies to tropical ecosystems, and discuss the need for more tropical research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. How to construct the statistic network? An association network of herbaceous

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2012-06-01

    Full Text Available In present study I defined a new type of network, the statistic network. The statistic network is a weighted and non-deterministic network. In the statistic network, a connection value, i.e., connection weight, represents connection strength and connection likelihood between two nodes and its absolute value falls in the interval (0,1]. The connection value is expressed as a statistical measure such as correlation coefficient, association coefficient, or Jaccard coefficient, etc. In addition, all connections of the statistic network can be statistically tested for their validity. A connection is true if the connection value is statistically significant. If all connection values of a node are not statistically significant, it is an isolated node. An isolated node has not any connection to other nodes in the statistic network. Positive and negative connection values denote distinct connectiontypes (positive or negative association or interaction. In the statistic network, two nodes with the greater connection value will show more similar trend in the change of their states. At any time we can obtain a sample network of the statistic network. A sample network is a non-weighted and deterministic network. Thestatistic network, in particular the plant association network that constructed from field sampling, is mostly an information network. Most of the interspecific relationships in plant community are competition and cooperation. Therefore in comparison to animal networks, the methodology of statistic network is moresuitable to construct plant association networks. Some conclusions were drawn from this study: (1 in the plant association network, most connections are weak and positive interactions. The association network constructed from Spearman rank correlation has most connections and isolated taxa are fewer. From net linear correlation,linear correlation, to Spearman rank correlation, the practical number of connections and connectance in the

  8. The influence of the Amazonian floodplain ecosystems on the trace element dynamics of the Amazon River mainstem (Brazil).

    Science.gov (United States)

    Viers, Jérôme; Barroux, Guénaël; Pinelli, Marcello; Seyler, Patrick; Oliva, Priscia; Dupré, Bernard; Boaventura, Geraldo Resende

    2005-03-01

    The purpose of this paper is to forecast the role of riverine wetlands in the transfer of trace elements. One of the largest riverine wetlands in the world is the floodplain (várzea) of the Amazon River and its tributaries (Junk and Piedade, 1997). The central Amazon wetlands are constituted by a complex network of lakes and floodplains, named várzeas, that extend over more than 300,000 km2 (Junk, W.J., The Amazon floodplain--a sink or source for organic carbon? In Transport of Carbon and Minerals in Major World Rivers, edited by E.T. Degens, S. Kempe, R. Herrera, SCOPE/UNEP; 267-283, 1985.) and are among the most productive ecosystems in the world due to the regular enrichment in nutrients by river waters In order to understand if the adjacent floodplain of Amazon River have a significant influence on the trace element concentrations and fluxes of the mainstem, the concentrations of selected elements (i.e., Al, Mn, Fe, Co, Cu, Mo, Rb, Sr, Ba, and U) have been measured in the Amazon River water (Manacapuru Station, Amazonas State, Brazil) and in lake waters and plants (leaves) from a várzea(Ilha de Marchantaria, Amazonas State, Brazil) during different periods of the hydrological cycle. Four plant species (two perennial species: Pseudobombax munguba and Salix humboldtiana, and two annual herbaceous plants: Echinochloa polystachya and Eichhornia crassipes) were selected to represent the ecological functioning of the site. Time series obtained for dissolved Mn and Cu (<0.20 microm) in Amazon River water could not be explained by tributary mixing or instream processes only. Therefore, the contribution of the waters transiting the floodplains should be considered. These results suggest that the chemical composition of the waters draining these floodplains is controlled by reactions occurring at sediment-water and plant-water interfaces. Trace elements concentrations in the plants (leaves) vary strongly with hydrological seasonality. Based on the concentration data

  9. Taxonomic distinctness of demersal fishes of the California current: moving beyond simple measures of diversity for marine ecosystem-based management.

    Directory of Open Access Journals (Sweden)

    Nick Tolimieri

    Full Text Available BACKGROUND: Large-scale patterns or trends in species diversity have long interested ecologists. The classic pattern is for diversity (e.g., species richness to decrease with increasing latitude. Taxonomic distinctness is a diversity measure based on the relatedness of the species within a sample. Here we examined patterns of taxonomic distinctness in relation to latitude (ca. 32-48 degrees N and depth (ca. 50-1220 m for demersal fishes on the continental shelf and slope of the US Pacific coast. METHODOLOGY/PRINCIPAL FINDINGS: Both average taxonomic distinctness (AvTD and variation in taxonomic distinctness (VarTD changed with latitude and depth. AvTD was highest at approximately 500 m and lowest at around 200 m bottom depth. Latitudinal trends in AvTD were somewhat weaker and were depth-specific. AvTD increased with latitude on the shelf (50-150 m but tended to decrease with latitude at deeper depths. Variation in taxonomic distinctness (VarTD was highest around 300 m. As with AvTD, latitudinal trends in VarTD were depth-specific. On the shelf (50-150 m, VarTD increased with latitude, while in deeper areas the patterns were more complex. Closer inspection of the data showed that the number and distribution of species within the class Chondrichthyes were the primary drivers of the overall patterns seen in AvTD and VarTD, while the relatedness and distribution of species in the order Scorpaeniformes appeared to cause the relatively low observed values of AvTD at around 200 m. CONCLUSIONS/SIGNIFICANCE: These trends contrast to some extent the patterns seen in earlier studies for species richness and evenness in demersal fishes along this coast and add to our understanding of diversity of the demersal fishes of the California Current.

  10. Ecosystem Services in the Water-Energy-Food Nexus

    Directory of Open Access Journals (Sweden)

    Bekchanov Maksud

    2015-01-01

    Full Text Available Given their substantial societal benefits, such as supporting economic activities and providing better livelihoods in rural areas, ecosystem services should gain higher importance in water-food-energy nexus debates. Yet, not all values from ecosystems are quantifiable, data is often not adequate and methods of measuring these values are not sound. This situation challenges researchers and water managers to improve research tools and give adequate attention to ecosystem services by implementing interdisciplinary approaches and integrated management of ecosystems and their services.

  11. Occurrence of different phytoplasma infections in wild herbaceous dicots growing in vineyards affected by bois noir in Tuscany (Italy

    Directory of Open Access Journals (Sweden)

    Guido MARCHI

    2015-12-01

    Full Text Available Wild herbaceous dicotyledonous plants (dicots showing symptoms ascribable to phytoplasma disorders were found to be widely distributed in organic vineyards in central Tuscany (Italy affected by bois noir, a grapevine yellows disease caused by “Candidatus Phytoplasma solani”. In 2010 symptomatic dicots were tentatively identified to species level and the incidence of symptoms estimated in two selected vineyards in the province of Florence. Incidence ranged from 2 to 77%, and was not related to the relative abundance of hosts since very common species as well as relatively rare ones were consistently found to be symptomatic. PCR indexing and 16S rRNA sequence analyses indicated that two phytoplasmas co-existed in the vineyards: “Ca. P. solani”, infecting the root systems of 17 taxa, and a phytoplasma closely related to “Ca. P. phoenicium”, infecting 11 taxa, and occasionally co-infecting the same plant. Regardless of the high frequency of both pathogens in the vineyards, only “Ca. P. solani” could be detected in the grapevines. Population screening by means of tuf sequence analyses revealed the presence of only the tuf-b “Ca. P. solani” type both in dicot hosts and grapevine. This supports current notions of bois noir epidemiology, indicating that some infected dicots act as sources of “Ca. P. solani” inoculum whereas others are dead-end hosts. When the same specimens were screened by sequence analysis of the vmp1 gene, evidence was found that different phytoplasma genotypes may be predominant in grapevines and dicots.

  12. Recovery dynamics and invasibility of herbaceous plant communities after exposure to fifty-year climate extremes in different seasons

    Directory of Open Access Journals (Sweden)

    F. E. Dreesen

    2013-10-01

    Full Text Available Disturbance events such as climatic extremes may enhance the invasibility of plant communities, through the creation of gaps and the associated local increase in available resources. In this study, experimental herbaceous communities consisting of three species were subjected to 50 yr extreme drought and/or heat events, in spring, summer or autumn. In the year of the induced extremes, species mortality and end-of-season biomass were examined. In two subsequent years without further disturbances, establishment of new species was recorded. The drought and drought + heat extremes in summer and autumn induced greater plant mortality compared with the heat extremes in those seasons and compared with all extremes applied in spring, in all three originally planted species. Recovery in terms of biomass towards the end of the growing season, however, was species-specific. The dominant species, the nitrogen fixer Trifolium repens, recovered poorly from the drought and drought + heat extremes which governed the community response. Community biomass, which was heavily affected by the drought and especially by the drought + heat events in summer and autumn, reached control values already one year later. Invasibility was increased in the communities that underwent the drought + heat extremes in the first year following the extreme events, but no longer in the second year. During the two years of invasion, the community composition changed, but independently of the type and impact of the extreme event. In short, the extreme climate events greatly affected the survival and productivity of the species, modified the species composition and dominance patterns, and increased the invasibility of our plant communities. However, none of these community properties seemed to be affected in the long term, as the induced responses faded out after one or two years.

  13. Rhizobium cauense sp. nov., isolated from root nodules of the herbaceous legume Kummerowia stipulacea grown in campus lawn soil.

    Science.gov (United States)

    Liu, Tian Yan; Li, Ying; Liu, Xiao Xiao; Sui, Xin Hua; Zhang, Xiao Xia; Wang, En Tao; Chen, Wen Xin; Chen, Wen Feng; Puławska, Joanna

    2012-10-01

    Three bacterial isolates (CCBAU 101002(T), CCBAU 101000 and CCBAU 101001) originating from root nodules of the herbaceous legume Kummerowia stipulacea grown in the campus lawn of China Agricultural University were characterized with a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence analysis showed that the isolates shared 99.85-99.92% sequence similarities and had the highest similarities to the type strains of Rhizobium mesoamericanum (99.31%), R. endophyticum (98.54%), R. tibeticum (98.38%) and R. grahamii (98.23%). Sequence similarity of four concatenated housekeeping genes (atpD, glnII, recA and rpoB) between CCBAU 101002(T) and its closest neighbor (R. grahamii) was 92.05%. DNA-DNA hybridization values between strain CCBAU 101002(T) and the four type strains of the most closely related Rhizobium species were less than 28.4±0.8%. The G+C mol% of the genomic DNA for strain CCBAU 101002(T) was 58.5% (Tm). The major respiratory quinone was ubiquinone (Q-10). Summed feature 8 (18:1ω7cis/18:1ω6cis) and 16:0 were the predominant fatty acids. Strain CCBAU 101002(T) contained phosphatidylcholine and phosphatidylethanolamine as major polar lipids, and phosphatidylglycerol and cardiolipin as minor ones. No glycolipid was detected. Unlike other strains, this novel species could utilize dulcite or sodium pyruvate as sole carbon sources and it was resistant to 2% (w/v) NaCl. On the basis of the polyphasic study, a new species Rhizobium cauense sp. nov. is proposed, with CCBAU 101002(T) (=LMG 26832(T)=HAMBI 3288(T)) as the type strain.

  14. Hyperaccumulation of Pb, Zn and Cd in herbaceous grown on lead-zinc mining area in Yunnan, China.

    Science.gov (United States)

    Yanqun, Zu; Yuan, Li; Jianjun, Chen; Haiyan, Chen; Li, Qin; Schvartz, Christian

    2005-07-01

    A field survey of herbaceous growing on lead-zinc mining area in Yunnan, China were conducted to identify species accumulating exceptionally large concentrations of Pb, Zn and Cd in shoots. In total, 220 plant samples of 129 species of 50 families and 220 soil samples in which the plants were growing were collected. According to accumulation concentration in plant shoots and the concentration time levels compared to plants from non-polluted environments, 21 plant samples of 16 species were chosen as best-performing specimens, 11 plant samples of 10 species for Pb, 5 plant samples of 4 species for Zn and 5 plant samples of 5 species for Cd. Sonchus asper (L.) Hill in Qilinkeng had hyperaccumulation capacity to Pb and Zn. Corydalis pterygopetala Franch in Paomaping had hyperaccumulation capacity to Zn and Cd. All 5 Cd hyperaccumulators came from Lanping lead-zinc mining area. Out of 11 Pb hyperaccumulators, 7 came from Minbingying of Huice lead-zinc mining area. The average of the concentration time levels compared to plants from non-polluted environments were higher than 10 times in all plant samples, the concentration time levels changed from 203 times to 620 times for Pb, from 50 times to 70 times for Zn and from 145 times to 330 times for Cd. Out of 21 plant samples, translocation factor changed from 0.35 to 1.90, only translocation factor of 7 plant samples were higher than 1. Enrichment coefficients of all samples were lower than 1. These plant species were primarily heavy metal hyperaccumulator, and will be used in phytoremediation of the metallic pollutants in soils after further research in accumulation mechanism.

  15. Identification of miRNAs Responsive to Botrytis cinerea in Herbaceous Peony (Paeonia lactiflora Pall. by High-Throughput Sequencing

    Directory of Open Access Journals (Sweden)

    Daqiu Zhao

    2015-09-01

    Full Text Available Herbaceous peony (Paeonia lactiflora Pall., one of the world’s most important ornamental plants, is highly susceptible to Botrytis cinerea, and improving resistance to this pathogenic fungus is a problem yet to be solved. MicroRNAs (miRNAs play an essential role in resistance to B. cinerea, but until now, no studies have been reported concerning miRNAs induction in P. lactiflora. Here, we constructed and sequenced two small RNA (sRNA libraries from two B. cinerea-infected P. lactiflora cultivars (“Zifengyu” and “Dafugui” with significantly different levels of resistance to B. cinerea, using the Illumina HiSeq 2000 platform. From the raw reads generated, 4,592,881 and 5,809,796 sRNAs were obtained, and 280 and 306 miRNAs were identified from “Zifengyu” and “Dafugui”, respectively. A total of 237 conserved and 7 novel sequences of miRNAs were differentially expressed between the two cultivars, and we predicted and annotated their potential target genes. Subsequently, 7 differentially expressed candidate miRNAs were screened according to their target genes annotated in KEGG pathways, and the expression patterns of miRNAs and corresponding target genes were elucidated. We found that miR5254, miR165a-3p, miR3897-3p and miR6450a might be involved in the P. lactiflora response to B. cinerea infection. These results provide insight into the molecular mechanisms responsible for resistance to B. cinerea in P. lactiflora.

  16. Continuous monitoring reveals multiple controls on ecosystem metabolism in a suburban stream.

    Science.gov (United States)

    Ecosystem metabolism is an important mechanism for nutrient retention in streams, yet few high studies have investigated temporal patterns in gross primary production (GPP) and ecosystem respiration (ER) using high frequency measurements. This is a potentially important oversig...

  17. A spatial assessment of ecosystem services in Europe - Phase II

    DEFF Research Database (Denmark)

    Maes, Joachim; Hauck, Jennifer; Paracchini,, Maria Luisa

    Mainstreaming ecosystem services in EU decision making processes requires a solid conceptual and methodological framework for mapping and assessing ecosystem services that serve the multiple objectives addressed by policies. The PRESS-2 study (PEER Research on Ecosystem Service – Phase 2) provides...... such an analytical framework which enables the operationalization of the present scientific knowledge base of environmental data and models for application by the EU and Member States for mapping and assessment of ecosystem services. This study was structured along three strands of work: policy and scenario analysis......, mapping and valuation. Linking the maps of ecosystem service supply to monetary valuation allowed an analysis of the expected impact of policy measures on benefits derived from ecosystem services. The recreation case, which Marianne participated in, presents evidence that millions of people visited...

  18. Plant functional traits predict green roof ecosystem services.

    Science.gov (United States)

    Lundholm, Jeremy; Tran, Stephanie; Gebert, Luke

    2015-02-17

    Plants make important contributions to the services provided by engineered ecosystems such as green roofs. Ecologists use plant species traits as generic predictors of geographical distribution, interactions with other species, and ecosystem functioning, but this approach has been little used to optimize engineered ecosystems. Four plant species traits (height, individual leaf area, specific leaf area, and leaf dry matter content) were evaluated as predictors of ecosystem properties and services in a modular green roof system planted with 21 species. Six indicators of ecosystem services, incorporating thermal, hydrological, water quality, and carbon sequestration functions, were predicted by the four plant traits directly or indirectly via their effects on aggregate ecosystem properties, including canopy density and albedo. Species average height and specific leaf area were the most useful traits, predicting several services via effects on canopy density or growth rate. This study demonstrates that easily measured plant traits can be used to select species to optimize green roof performance across multiple key services.

  19. A spatial assessment of ecosystem services in Europe - Phase II

    DEFF Research Database (Denmark)

    Maes, Joachim; Hauck, Jennifer; Paracchini,, Maria Luisa

    , mapping and valuation. Linking the maps of ecosystem service supply to monetary valuation allowed an analysis of the expected impact of policy measures on benefits derived from ecosystem services. The recreation case, which Marianne participated in, presents evidence that millions of people visited......Mainstreaming ecosystem services in EU decision making processes requires a solid conceptual and methodological framework for mapping and assessing ecosystem services that serve the multiple objectives addressed by policies. The PRESS-2 study (PEER Research on Ecosystem Service – Phase 2) provides...... such an analytical framework which enables the operationalization of the present scientific knowledge base of environmental data and models for application by the EU and Member States for mapping and assessment of ecosystem services. This study was structured along three strands of work: policy and scenario analysis...

  20. Economic viewpoints on ecosystem services

    NARCIS (Netherlands)

    Silvis, H.J.; Heide, van der C.M.

    2013-01-01

    to help determine the different values of ecosystems. Ecosystem services are usually divided into four categories: provisioning services, regulating services, cultural services and habitat services (previously denoted as supporting services). This overview highlights economic theories about

  1. Economic viewpoints on ecosystem services

    NARCIS (Netherlands)

    Silvis, H.J.; Heide, van der C.M.

    2013-01-01

    to help determine the different values of ecosystems. Ecosystem services are usually divided into four categories: provisioning services, regulating services, cultural services and habitat services (previously denoted as supporting services). This overview highlights economic theories about ecosyste

  2. The herbaceous landlord: integrating the effects of symbiont consortia within a single host.

    Science.gov (United States)

    Vandegrift, Roo; Roy, Bitty A; Pfeifer-Meister, Laurel; Johnson, Bart R; Bridgham, Scott D

    2015-01-01

    Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC) by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.

  3. The herbaceous landlord: integrating the effects of symbiont consortia within a single host

    Directory of Open Access Journals (Sweden)

    Roo Vandegrift

    2015-11-01

    Full Text Available Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF and dark septate endophytes (DSE in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.

  4. Distributive justice in the international regulation of global ecosystem services

    NARCIS (Netherlands)

    Davidson, M.D.

    2012-01-01

    Incentive measures can internalize the external benefits of ecosystem services or, conversely, the external costs of service losses. In the last decade, preliminary steps have been taken in this direction in the form of voluntary payments for ecosystem services. Much larger financial flows may be re

  5. Economic Valuation Tools and their Applications to Ecosystem Services

    Science.gov (United States)

    Many of the ecosystem services that people value are not normally bought and sold; yet, this does not mean they have no measurable economic value. Economists have developed a set of approaches and tools for valuing the full range of both market and “non-market” ecosystem goods an...

  6. Estimation of evapotranspiration over the terrestrial ecosystems in China

    Science.gov (United States)

    Xianglan Li; Shunlin Liang; Wenping Yuan; Guirui Yu; Xiao Cheng; Yang Chen; Tianbao Zhao; Jinming Feng; Zhuguo Ma; Mingguo Ma; Shaomin Liu; Jiquan Chen; Changliang Shao; Shenggong Li; Xudong Zhang; Zhiqiang Zhang; Ge Sun; Shiping Chen; Takeshi Ohta; Andrej Varlagin; Akira Miyata; Kentaro Takagi; Nobuko Saiqusa; Tomomichi Kato

    2014-01-01

    Quantifying regional evapotranspiration (ET) and environmental constraints are particularly important for understanding water and carbon cycles of terrestrial ecosystems. However, a large uncertainty in the regional estimation of ET still remains for the terrestrial ecosystems in China. This study used ET measurements of 34 eddy covariance sites within China and...

  7. Distributive justice in the international regulation of global ecosystem services

    NARCIS (Netherlands)

    Davidson, M.D.

    2012-01-01

    Incentive measures can internalize the external benefits of ecosystem services or, conversely, the external costs of service losses. In the last decade, preliminary steps have been taken in this direction in the form of voluntary payments for ecosystem services. Much larger financial flows may be

  8. Using Radiocarbon to Test Models of Ecosystem Carbon Cycling

    Science.gov (United States)

    Trumbore, S.; Lin, H.; Randerson, J.

    2007-05-01

    The radiocarbon content of carbon stored in and respired by ecosystems provides a direct measure of ecosystem carbon dynamics that can be directly compared to model predictions. Because carbon cycles through ecosystems on a variety of timescales, the mean age of C in standing biomass and soil organic matter pools is older than the mean age of microbially respired carbon. In turn, each pathway for C transit through ecosystems my respond differently to edaphic conditions; for example, soil organic matter mean age is controlled by factors affecting stabilization of C on very long timescales, such as mineralogy, while a factor like litter quality that effects decomposition rates reflects vegetation and climate characteristics. We compare the radiocarbon signature of heterotrophically respired CO2 across a number of ecosystems with models predicted using the CASA ecosystem model. The major controls of microbially respired CO2 from ecosystems include the residence time of C in living plant pools (i.e. the age of C in litter inputs to soil) and factors that control decomposition rates (litter quality and climate). Major differences between model and measured values at low latitudes are related to how woody debris pools are treated differently in models and measurements. The time lag between photosynthesis and respiration is a key ecosystem property that defines its potential to store or release carbon given variations in annual net primary production. Radiocarbon provides a rare case where models can be directly compared with measurements to provide a test of this parameter.

  9. Benefits of investing in ecosystem restoration

    NARCIS (Netherlands)

    Groot, de R.S.; Blignaut, J.; Ploeg, van der S.; Aronson, J.; Elmqvist, T.; Farley, J.

    2013-01-01

    Measures aimed at conservation or restoration of ecosystems are often seen as net-cost projects by governments and businesses because they are based on incomplete and often faulty cost-benefit analyses. After screening over 200 studies, we examined the costs (94 studies) and benefits (225 studies) o

  10. Benefits of investing in ecosystem restoration.

    Science.gov (United States)

    DE Groot, Rudolf S; Blignaut, James; VAN DER Ploeg, Sander; Aronson, James; Elmqvist, Thomas; Farley, Joshua

    2013-12-01

    Measures aimed at conservation or restoration of ecosystems are often seen as net-cost projects by governments and businesses because they are based on incomplete and often faulty cost-benefit analyses. After screening over 200 studies, we examined the costs (94 studies) and benefits (225 studies) of ecosystem restoration projects that had sufficient reliable data in 9 different biomes ranging from coral reefs to tropical forests. Costs included capital investment and maintenance of the restoration project, and benefits were based on the monetary value of the total bundle of ecosystem services provided by the restored ecosystem. Assuming restoration is always imperfect and benefits attain only 75% of the maximum value of the reference systems over 20 years, we calculated the net present value at the social discount rates of 2% and 8%. We also conducted 2 threshold cum sensitivity analyses. Benefit-cost ratios ranged from about 0.05:1 (coral reefs and coastal systems, worst-case scenario) to as much as 35:1 (grasslands, best-case scenario). Our results provide only partial estimates of benefits at one point in time and reflect the lower limit of the welfare benefits of ecosystem restoration because both scarcity of and demand for ecosystem services is increasing and new benefits of natural ecosystems and biological diversity are being discovered. Nonetheless, when accounting for even the incomplete range of known benefits through the use of static estimates that fail to capture rising values, the majority of the restoration projects we analyzed provided net benefits and should be considered not only as profitable but also as high-yielding investments. Beneficios de Invertir en la Restauración de Ecosistemas.

  11. Investigating Ecosystems in a Biobottle

    Science.gov (United States)

    Breene, Arnica; Gilewski, Donna

    2008-01-01

    Biobottles are miniature ecosystems made from 2-liter plastic soda bottles. They allow students to explore how organisms in an ecosystem are connected to each other, examine how biotic and abiotic factors influence plant and animal growth and development, and discover how important biodiversity is to an ecosystem. This activity was inspired by an…

  12. The Coevolution of Digital Ecosystems

    Science.gov (United States)

    SungYong, Um

    2016-01-01

    Digital ecosystems are one of the most important strategic issues in the current digital economy. Digital ecosystems are dynamic and generative. They evolve as new firms join and as heterogeneous systems are integrated into other systems. These features digital ecosystems determine economic and technological success in the competition among…

  13. Ecosystems in the Learning Environment

    Science.gov (United States)

    Louviere, Gregory

    2011-01-01

    Habitats, ecology and evolution are a few of the many metaphors commonly associated with the domain of biological ecosystems. Surprisingly, these and other similar biological metaphors are proving to be equally associated with a phenomenon known as digital ecosystems. Digital ecosystems make a direct connection between biological properties and…

  14. Ecosystems in the Learning Environment

    Science.gov (United States)

    Louviere, Gregory

    2011-01-01

    Habitats, ecology and evolution are a few of the many metaphors commonly associated with the domain of biological ecosystems. Surprisingly, these and other similar biological metaphors are proving to be equally associated with a phenomenon known as digital ecosystems. Digital ecosystems make a direct connection between biological properties and…

  15. The Coevolution of Digital Ecosystems

    Science.gov (United States)

    SungYong, Um

    2016-01-01

    Digital ecosystems are one of the most important strategic issues in the current digital economy. Digital ecosystems are dynamic and generative. They evolve as new firms join and as heterogeneous systems are integrated into other systems. These features digital ecosystems determine economic and technological success in the competition among…

  16. Investigating Ecosystems in a Biobottle

    Science.gov (United States)

    Breene, Arnica; Gilewski, Donna

    2008-01-01

    Biobottles are miniature ecosystems made from 2-liter plastic soda bottles. They allow students to explore how organisms in an ecosystem are connected to each other, examine how biotic and abiotic factors influence plant and animal growth and development, and discover how important biodiversity is to an ecosystem. This activity was inspired by an…

  17. Forecasting sagebrush ecosystem components and greater sage-grouse habitat for 2050: learning from past climate patterns and Landsat imagery to predict the future

    Science.gov (United States)

    Homer, Collin G.; Xian, George Z.; Aldridge, Cameron L.; Meyer, Debra K.; Loveland, Thomas R.; O'Donnell, Michael S.

    2015-01-01

    Sagebrush (Artemisia spp.) ecosystems constitute the largest single North American shrub ecosystem and provide vital ecological, hydrological, biological, agricultural, and recreational ecosystem services. Disturbances have altered and reduced this ecosystem historically, but climate change may ultimately represent the greatest future risk. Improved ways to quantify, monitor, and predict climate-driven gradual change in this ecosystem is vital to its future management. We examined the annual change of Daymet precipitation (daily gridded climate data) and five remote sensing ecosystem sagebrush vegetation and soil components (bare ground, herbaceous, litter, sagebrush, and shrub) from 1984 to 2011 in southwestern Wyoming. Bare ground displayed an increasing trend in abundance over time, and herbaceous, litter, shrub, and sagebrush showed a decreasing trend. Total precipitation amounts show a downward trend during the same period. We established statistically significant correlations between each sagebrush component and historical precipitation records using a simple least squares linear regression. Using the historical relationship between sagebrush component abundance and precipitation in a linear model, we forecasted the abundance of the sagebrush components in 2050 using Intergovernmental Panel on Climate Change (IPCC) precipitation scenarios A1B and A2. Bare ground was the only component that increased under both future scenarios, with a net increase of 48.98 km2 (1.1%) across the study area under the A1B scenario and 41.15 km2 (0.9%) under the A2 scenario. The remaining components decreased under both future scenarios: litter had the highest net reductions with 49.82 km2 (4.1%) under A1B and 50.8 km2 (4.2%) under A2, and herbaceous had the smallest net reductions with 39.95 km2 (3.8%) under A1B and 40.59 km2 (3.3%) under A2. We applied the 2050 forecast sagebrush component values to contemporary (circa 2006) greater sage-grouse (Centrocercus

  18. Estimating vegetation dryness to optimize fire risk assessment with spot vegetation satellite data in savanna ecosystems

    Science.gov (United States)

    Verbesselt, J.; Somers, B.; Lhermitte, S.; van Aardt, J.; Jonckheere, I.; Coppin, P.

    2005-10-01

    The lack of information on vegetation dryness prior to the use of fire as a management tool often leads to a significant deterioration of the savanna ecosystem. This paper therefore evaluated the capacity of SPOT VEGETATION time-series to monitor the vegetation dryness (i.e., vegetation moisture content per vegetation amount) in order to optimize fire risk assessment in the savanna ecosystem of Kruger National Park in South Africa. The integrated Relative Vegetation Index approach (iRVI) to quantify the amount of herbaceous biomass at the end of the rain season and the Accumulated Relative Normalized Difference vegetation index decrement (ARND) related to vegetation moisture content were selected. The iRVI and ARND related to vegetation amount and moisture content, respectively, were combined in order to monitor vegetation dryness and optimize fire risk assessment in the savanna ecosystems. In situ fire activity data was used to evaluate the significance of the iRVI and ARND to monitor vegetation dryness for fire risk assessment. Results from the binary logistic regression analysis confirmed that the assessment of fire risk was optimized by integration of both the vegetation quantity (iRVI) and vegetation moisture content (ARND) as statistically significant explanatory variables. Consequently, the integrated use of both iRVI and ARND to monitor vegetation dryness provides a more suitable tool for fire management and suppression compared to other traditional satellite-based fire risk assessment methods, only related to vegetation moisture content.

  19. Payment for ecosystem services

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Oddershede, Jakob Stoktoft; Pedersen, Anders Branth;

    Research question: Northern Europe experiences an increasingly wet climate, leading to more frequent and severe fluvial flood events. Ecosystem-based Adaptation (EbA) is becoming recognised as a valuable yet under-utilised means to alleviating negative effects of a changing climate. This however...... that would allow the local municipality to periodically flood farmland in order to avoid or limit urban flooding from Storåen. The experiment aims to estimate the costs of getting farmers to participate in the scheme, which would represent (some of) the costs of reducing climate change problems in the town...... and based on individual negotiation would on average require a yearly payment of 309euro/ha. Significance for practical solutions: This type of analysis investigates attitudes and preferences of land owners, which are essential when dealing with Ecosystem-based Adaptation. Past experience shows that without...

  20. Stress in ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Jerneloev, A.; Wahlgren, U.

    1981-03-01

    A stress concept which relates to energy flows through eco-systems is suggested. The concept is introduced after discussion of observed phenomena. The need of quantifying of responses to external pressure is printed out. The efficiency of the systems may be defined as the degree of utilization of the available energy, and such factors may used for definitions of stress. The concepts are visualized in terms of quantities obtained from simple Lotka-Volterra-type equations.

  1. Marine Ecosystem Services

    DEFF Research Database (Denmark)

    Hasler, Berit; Ahtiainen, Heini; Hasselström, Linus

    MARECOS (Marine Ecosystem Services) er et tværfagligt studie, der har haft til formål at tilvejebringe information vedrørende kortlægning og værdisætning af økosystemtjenester, som kan anvendes i forbindelse med udformning af regulering på det marine område såvel nationalt, som regionalt og...

  2. Marine Ecosystem Services

    DEFF Research Database (Denmark)

    Hasler, Berit; Ahtiainen, Heini; Hasselström, Linus

    MARECOS (Marine Ecosystem Services) er et tværfagligt studie, der har haft til formål at tilvejebringe information vedrørende kortlægning og værdisætning af økosystemtjenester, som kan anvendes i forbindelse med udformning af regulering på det marine område såvel nationalt, som regionalt og inter...

  3. Sagebrush Ecosystems Under Fire

    Energy Technology Data Exchange (ETDEWEB)

    Downs, Janelle L.

    2014-12-30

    Since settlement of the western United States began, sagebrush (Artemisia L. spp.) ecosystems have decreased both in quantity and quality. Originally encompassing up to 150 million acres in the West, the “interminable fields” of sage described by early explorers (Fremont 1845) have been degraded and often eliminated by conversion to agriculture, urbanization, livestock grazing, invasion by alien plants, and alteration of wildfire cycles (Hann et al. 1997; West 1999). More than half of the original sagebrush steppe ecosystems in Washington have been converted to agriculture and many of the remaining stands of sagebrush are degraded by invasion of exotic annuals such as cheatgrass (Bromus tectorum L.). Today, sagebrush ecosystems are considered to be one of the most imperiled in the United States (Noss, LeRoe and Scott 1995), and more than 350 sagebrush-associated plants and animals have been identified as species of conservation concern (Suring et al. 2005; Wisdom et al. 2005). The increasing frequency of wildfire in sagebrush-dominated landscapes is one of the greatest threats to these habitats and also presents one of the most difficult to control.

  4. Ecosystem Management. A Management View

    DEFF Research Database (Denmark)

    Ravn-Jonsen, Lars

    The need for management of the marine ecosystem using a broad perspective has been recommended under a variety of names. This paper uses the term Ecosystem Management, which is seen as a convergence between the ecological idea of an organisational hierarchy and the idea of strategic planning...... with a planning hierarchy---with the ecosystem being the strategic planning level. Management planning requires, in order to establish a quantifiable means and ends chain, that the goals at the ecosystem level can be linked to operational levels; ecosystem properties must therefore be reducible to lower...

  5. Impact of Point and Non-point Source Pollution on Coral Reef Ecosystems In Mamala Bay, Oahu, Hawaii based on Water Quality Measurements and Benthic Surveys in 1993-1994 (NODC Accession 0001172)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The effects of both point and non-point sources of pollution on coral reef ecosystems in Mamala Bay were studied at three levels of biological organization; the...

  6. Soil compaction related to grazing and its effects on herbaceous roots frequency and soil organic matter content in rangelands of SW Spain

    Science.gov (United States)

    Pulido, Manuel; Schnabel, Susanne; Francisco Lavado Contador, Joaquín; Miralles Mellado, Isabel

    2016-04-01

    Rangelands in SW Spain occupy a total surface area of approximately 6 million ha and constitute the most representative extensive ranching system of the Iberian Peninsula gathering more than 13 million livestock heads. They are characterised by an herbaceous layer, mostly composed of therophytic species, with a disperse tree cover, mainly holm oak and cork oak (Quercus ilex rotundifolia and Q. suber), interspersed with shrubs in many places. This type of land system is of ancient origin and experienced frequent changes in land use in the past, since agricultural, livestock and forestry activities have coexisted within the same farms. In recent decades, livestock farming has become dominant due, in part, to the subsidies of the Common Agriculture Policy. Since Spain joined the European Union in 1986 until the year 2000, the number of domestic animals doubled, particularly cattle, and consequently animal stocking rates have increased on average from 0.40 AU ha-1 up to 0.70 AU ha-1. This increase in animal stocking rates, along with a progressive substitution of cattle instead of sheep in many farms, has led to the occurrence of land degradation processes such as the reduction of grass cover or soil compaction in heavily grazed areas. Previous research has evidenced higher values of soil bulk density and resistance to penetration as well as larger bare surface areas in spring in fenced areas with animal stocking rates above 1 AU ha-1. However, a better understanding of how increasing bulk density or resistance to penetration influence the frequency of herbaceous roots and how a reduction in the frequency of roots affects soil organic matter content in rangelands is still unknown. Therefore, the main goal of this study was to determine possible relationships between the frequencies of herbaceous roots and soil organic matter content in order to unders