Space sequestration below ground in old-growth spruce-beech forests – signs for facilitation?

Directory of Open Access Journals (Sweden)

Andreas eBolte

2013-08-01

Full Text Available Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤ 2 mm by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1 spruce as a central tree, (2 spruce as competitor, (3 beech as a central tree, and (4 beech as competitor. Mean values of life fine root attributes like biomass (FRB, length (FRL, and root area index (RAI were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA, asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

Ground penetrating radar system and method for detecting an object on or below a ground surface

NARCIS (Netherlands)

De Jongth, R.; Yarovoy, A.; Schukin, A.

2001-01-01

Ground penetrating radar system for detecting objects (17) on or below a ground surface (18), comprising at least one transmit antenna (13) having a first foot print (14) at the ground surface, at least one receive antenna (15) having a second foot print (16) at the ground surface, and processing

POLICY FRAMEWORK FOR UTILIZATION AND CONSERVATION OF BELOW-GROUND BIODIVERSITY IN KENYA

Directory of Open Access Journals (Sweden)

Celline Achieng

2009-10-01

Full Text Available The reasons for the lack of inclusion of below-ground biodiversity in the Kenyan policy and legal framework were sought. Gaps were identified in the relevant sectoral policies and laws in regard to the domestication of the Convention on Biological Diversity (CBD. Below -ground biodiversity had no specific schedule in any of the sectoral laws. Most sectoral laws were particular about the larger biodiversity and soils but had no mention of below-ground biodiversity. Material Transfer Agreements and Material Acquisition Agreements that are regarded as tools of domestication of the CBD to guide transfers, exchanges and acquisition of soil organisms lacked a regulating policy. The lack of regulating policy could be attributed to the delay in approval of draft regulations by the Ministry of Environment while the lack of inclusion of below-ground biodiversity in Kenya’s legal and policy framework could be as a result of lack of awareness and appreciation among stakeholders.

High yielding biomass genotypes of willow (Salix spp.) show differences in below ground biomass allocation

International Nuclear Information System (INIS)

Cunniff, Jennifer; Purdy, Sarah J.; Barraclough, Tim J.P.; Castle, March; Maddison, Anne L.; Jones, Laurence E.; Shield, Ian F.; Gregory, Andrew S.; Karp, Angela

2015-01-01

Willows (Salix spp.) grown as short rotation coppice (SRC) are viewed as a sustainable source of biomass with a positive greenhouse gas (GHG) balance due to their potential to fix and accumulate carbon (C) below ground. However, exploiting this potential has been limited by the paucity of data available on below ground biomass allocation and the extent to which it varies between genotypes. Furthermore, it is likely that allocation can be altered considerably by environment. To investigate the role of genotype and environment on allocation, four willow genotypes were grown at two replicated field sites in southeast England and west Wales, UK. Above and below ground biomass was intensively measured over two two-year rotations. Significant genotypic differences in biomass allocation were identified, with below ground allocation differing by up to 10% between genotypes. Importantly, the genotype with the highest below ground biomass also had the highest above ground yield. Furthermore, leaf area was found to be a good predictor of below ground biomass. Growth environment significantly impacted allocation; the willow genotypes grown in west Wales had up to 94% more biomass below ground by the end of the second rotation. A single investigation into fine roots showed the same pattern with double the volume of fine roots present. This greater below ground allocation may be attributed primarily to higher wind speeds, plus differences in humidity and soil characteristics. These results demonstrate that the capacity exists to breed plants with both high yields and high potential for C accumulation. - Highlights: • SRC willows are a source of biomass and act as carbon (C) sinks. • Biomass allocation was measured in 4 willow genotypes grown in two UK field sites. • The greatest yielding genotype had the greatest below ground biomass at both sites. • Below ground biomass allocation differed by up to 10% between genotypes and 94% between sites. • Environment e.g. wind

Effects of above-ground plant species composition and diversity on the diversity of soil-borne microorganisms

NARCIS (Netherlands)

Kowalchuk, G.A.; Buma, D.S; De Boer, W.; Klinkhamer, P.G.L.; Van Veen, J.A.

2002-01-01

A coupling of above-ground plant diversity and below-ground microbial diversity has been implied in studies dedicated to assessing the role of macrophyte diversity on the stability, resilience, and functioning of ecosystems. Indeed, above-ground plant communities have long been assumed to drive

UV-B-mediated changes on below-ground communities associated with the roots of Acer saccharum

International Nuclear Information System (INIS)

Klironomos, J.N.; Allen, M.F.

1995-01-01

1. Little is known about how exposure to UV-B radiation affects rhizosphere microbes. Rhizosphere organisms are fed primarily by root-derived substrates and fulfil functions such as mineralization, immobilization, decomposition, pathogeneity and improvement of plant nutrition; they form the base of the below-ground food web. 2. In this study, we exposed Sugar Maple (Acer saccharum) seedlings to UV-B radiation in order to determine if UV-B influences the activities of mycorrhizal and non-mycorrhizal fungi, bacteria and microbe-feeding arthropods in the rhizosphere. 3. Below-ground organisms are greatly affected by UV-B radiation. Overall, carbon-flow in the plant soil system was shifted from a mutualistic-closed, mycorrhizal-dominated system to an opportunist-open, saprobe/pathogen-dominated one. (author)

A below-ground herbivore shapes root defensive chemistry in natural plant populations

OpenAIRE

Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Th?o; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

2016-01-01

Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root ...

Review on the effects of toxicants on freshwater ecosystem functions

International Nuclear Information System (INIS)

Peters, K.; Bundschuh, M.; Schäfer, R.B.

2013-01-01

We reviewed 122 peer-reviewed studies on the effects of organic toxicants and heavy metals on three fundamental ecosystem functions in freshwater ecosystems, i.e. leaf litter breakdown, primary production and community respiration. From each study meeting the inclusion criteria, the concentration resulting in a reduction of at least 20% in an ecosystem function was standardized based on median effect concentrations of standard test organisms (i.e. algae and daphnids). For pesticides, more than one third of observations indicated reductions in ecosystem functions at concentrations that are assumed being protective in regulation. Moreover, the reduction in leaf litter breakdown was more pronounced in the presence of invertebrate decomposers compared to studies where only microorganisms were involved in this function. High variability within and between studies hampered the derivation of a concentration–effect relationship. Hence, if ecosystem functions are to be included as protection goal in chemical risk assessment standardized methods are required. -- Highlights: •Quantitative review of 122 studies on effects of toxicants on ecosystem functions. •Variation between studies hampered derivation of concentration–effect relationships. •Adverse effects of pesticide were observed below thresholds corresponding to regulation. •Effects on leaf breakdown were greater when invertebrates were involved. -- Concentrations assumed as protective in chemical regulation cause adverse effects in three fundamental ecosystem functions

Ecosystem-scale fluxes in seminatural Pyrenean grasslands: role of annual dynamics of plant functional types

Science.gov (United States)

Altimir, Nuria; Ibañez, Mercedes; Elbers, Jan; Rota, Cristina; Arias, Claudia; Carrara, Arnaud; Nogues, Salvador; Sebastia, Maria-Teresa

2013-04-01

The net ecosystem exchange (NEE) and the annual C balance of a site are in general modulated by light, temperature and availability of water and other resources to the plants. In grasslands, NEE is expected to depend strongly on the vegetation with a relationship that can be summarized by the above-ground biomass, its amount and dynamics. Any factor controlling the amount of green biomass is expected to have a strong impact on the short-term NEE, such as amount of solar radiation, water availability and grazing pressure. These controls are modulated differently depending on the plant functional type enduring them. Furthermore, as different guilds follow different functional strategies for optimization of the resources, they also present different patterns of change in their capacities such as photosynthetic fixation, belowground C allocation, and C loss via respiration. We examined these relationships at several semi-natural pastures to determine how the seasonal distribution of plant functional types is detected in the short-term ecosystem exchange and what role it plays. We have looked into these patterns to determine the general variation of key processes and whether different temporal patterns arise between different guilds. The study sites are in the Pyrenees, on the mountain pastures of La Bertolina, Alinyà, and Castellar at 1300, 1700, 1900 m a.s.l. respectively. We performed ecosystem-scale flux measurements by means of micrometeorologial stations combined with a thorough description of the vegetation including below- and above-ground biomass and leaf area as well as monitoring of natural abundance of C isotopes, discriminated by plant functional types. We present here the results of the study.

Combined effects of agrochemicals and ecosystem services on crop yield across Europe.

Science.gov (United States)

Gagic, Vesna; Kleijn, David; Báldi, András; Boros, Gergely; Jørgensen, Helene Bracht; Elek, Zoltán; Garratt, Michael P D; de Groot, G Arjen; Hedlund, Katarina; Kovács-Hostyánszki, Anikó; Marini, Lorenzo; Martin, Emily; Pevere, Ines; Potts, Simon G; Redlich, Sarah; Senapathi, Deepa; Steffan-Dewenter, Ingolf; Świtek, Stanislaw; Smith, Henrik G; Takács, Viktória; Tryjanowski, Piotr; van der Putten, Wim H; van Gils, Stijn; Bommarco, Riccardo

2017-11-01

Simultaneously enhancing ecosystem services provided by biodiversity below and above ground is recommended to reduce dependence on chemical pesticides and mineral fertilisers in agriculture. However, consequences for crop yield have been poorly evaluated. Above ground, increased landscape complexity is assumed to enhance biological pest control, whereas below ground, soil organic carbon is a proxy for several yield-supporting services. In a field experiment replicated in 114 fields across Europe, we found that fertilisation had the strongest positive effect on yield, but hindered simultaneous harnessing of below- and above-ground ecosystem services. We furthermore show that enhancing natural enemies and pest control through increasing landscape complexity can prove disappointing in fields with low soil services or in intensively cropped regions. Thus, understanding ecological interdependences between land use, ecosystem services and yield is necessary to promote more environmentally friendly farming by identifying situations where ecosystem services are maximised and agrochemical inputs can be reduced. © 2017 John Wiley & Sons Ltd/CNRS.

Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

International Nuclear Information System (INIS)

Jones, M.L.M.; Hodges, G.; Mills, G.

2010-01-01

Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha -1 yr -1 . Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

Effects of above- and below-ground competition from shrubs on photosynthesis, transpiration and growth in Quercus robur L

Science.gov (United States)

Anna M. Jensen; Magnus Lof; Emile S. Gardiner

2011-01-01

For a tree seedling to successfully establish in dense shrubbery, it must maintain function under heterogeneous resource availability. We evaluated leaf-level acclimation in photosynthetic capacity, seedling-level transpiration, and seedling morphology and growth to gain an understanding of the effects of above- and below-ground competition on Quercus robur seedlings....

Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

International Nuclear Information System (INIS)

Chen, Hao; Li, Dejun; Gurmesa, Geshere A.; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

2015-01-01

Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. - Highlights: • Meta-analysis was used to address the effects of N addition on C cycle. • N addition caused an large decease in belowground plant C pool. • N-rich and N-limited ecosystems had different responses to N addition. - N addition caused a large decrease in below-ground plant C pool.

Exposure to radon in dwellings below the ground level in the area of Zagreb

International Nuclear Information System (INIS)

Lokobauer, N.; Franic, Z.; Sokolovic, E.; Petroci, L.; Sencar, J.; Lokner, V.

1998-01-01

Radon measurements were carried out in 44 dwellings at 22 locations in the area of Zagreb with the aim of establishing possible differences in radon levels between dwellings located below ground level, and those on higher floors. The measurements were performed using a Honeywell professional radon monitor both during the spring/summer and the autumn/winter seasons. Significant differences were found: for dwellings below ground level, the average annual radon activity concentration was 57±20 Bqm -3 ; for those on higher floors the value was 35±15 Bqm -3 . (A.K.)

THE EFFECT OF OZONE ON BELOW-GROUND CARBON ALLOCATION IN WHEAT

Science.gov (United States)

Short term 14CO2 pulse and chase experiments were conducted in order to investigate the effect ozone on below-ground carbon allocation in spring wheat seedlings (Triticum aestivumL. ?ANZA'). Wheat seedlings were grown in a sand-hydroponic system and exposed to either high ozone ...

Effect of ecosystems substitutions and CO2 increase of the atmosphere on the microbial ecosystems of forests

International Nuclear Information System (INIS)

Martin, F.

2007-01-01

Biological diversity is often exclusively considered at the level of plants and animals, whereas the bulk of global biodiversity is in fact at the microbial level. Although it is clear that the ecology of our planet is driven by microbial ecosystems, we are severely hampered by our limited understanding of the diversity and function of such microbial ecosystems. In the present project, teams in the disciplines of geochemistry, soil microbiology, genomics and ecosystem processes are assembled to study the relationship between environmental change, land use changes, biodiversity, and functioning of forest ecosystems. The network has a strong focus on developing and applying biochemical and genotyping methodologies to address key scientific issues in soil microbial ecology. These include assessing the impact of environmental- and land use changes on microbial diversity and function and exploring the evolutionary and mechanistic links between biological diversity and ecosystem function. In the present study, we have shown that: (1) The native mixed forest showed the highest microbial diversity (2) The mono specific plantations of tree species (e.g., oak, beech, pine, spruce) strikingly alter genetic and functional diversities of soil bacterial and fungal species. (3) Bacterial denitrification rates were dramatically modified by the planted species. Only by taking into account the impact of forest management on below-ground microbial diversity can one hope to get a full ecosystem-based understanding, and this must be addressed via modelling in order to provide relevant and useful information for conservation and policy making. (author)

Changes in ground beetle assemblages above and below the treeline of the Dolomites after almost 30 years (1980/2009).

Science.gov (United States)

Pizzolotto, Roberto; Gobbi, Mauro; Brandmayr, Pietro

2014-04-01

Very little is known about the changes of ground beetle assemblages in the last few decades in the Alps, and different responses to climate change of animal populations living above and below the treeline have not been estimated yet. This study focuses on an altitudinal habitat sequence from subalpine spruce forest to alpine grassland in a low disturbance area of the southeastern Dolomites in Italy, the Paneveggio Regional Park. We compared the ground beetle (Carabidae) populations sampled in 1980 in six stands below and above the treeline (1650-2250 m a.s.l.) with those sampled in the same sites almost 30 years later (2008/9). Quantitative data (species richness and abundance) have been compared by means of several diversity indexes and with a new index, the Index of Rank-abundance Change (IRC). Our work shows that species richness and abundance have changed after almost 30 years as a consequence of local extinctions, uphill increment of abundance and uphill shift of distribution range. The overall species number dropped from 36 to 27, while in the sites above the treeline, species richness and abundance changed more than in the forest sites. Two microtherm characteristic species of the pioneer cushion grass mats, Nebria germari and Trechus dolomitanus, became extinct or showed strong abundance reduction. In Nardetum pastures, several hygrophilic species disappeared, and xerophilic zoophytophagous elements raised their population density. In forest ecosystems, the precipitation reduction caused deep soil texture and watering changes, driving a transformation from Sphagnum-rich (peaty) to humus-rich soil, and as a consequence, soil invertebrate biomass strongly increased and thermophilic carabids enriched the species structure. In three decades, Carabid assemblages changed consistently with the hypothesis that climate change is one of the main factors triggering natural environment modifications. Furthermore, the level of human disturbance could enhance the

Mind the Roots: Phenotyping Below-Ground Crop Diversity and Its Influence on Final Yield

Science.gov (United States)

Nieters, C.; Guadagno, C. R.; Lemli, S.; Hosseini, A.; Ewers, B. E.

2017-12-01

Changes in global climate patterns and water regimes are having profound impacts on worldwide crop production. An ever-growing population paired with increasing temperatures and unpredictable periods of severe drought call for accurate modeling of future crop yield. Although novel approaches are being developed in high-throughput, above-ground image phenotyping, the below-ground plant system is still poorly phenotyped. Collection of plant root morphology and hydraulics are needed to inform mathematical models to reliably estimate yields of crops grown in sub-optimal conditions. We used Brassica rapa to inform our model as it is a globally cultivated crop with several functionally diverse cultivars. Specifically, we use 7 different accessions from oilseed (R500 and Yellow Sarson), leafy type (Pac choi and Chinese cabbage), a vegetable turnip, and two Wisconsin Fast Plants (Imb211 and Fast Plant self-compatible), which have shorter life cycles and potentially large differences in allocation to roots. Bi-weekly, we harvested above and below-ground biomass to compare the varieties in terms of carbon allocation throughout their life cycle. Using WinRhizo software, we analyzed root system length and surface area to compare and contrast root morphology among cultivars. Our results confirm that root structural characteristics are crucial to explain plant water use and carbon allocation. The root:shoot ratio reveals a significant (p physiological traits such as gas exchange, chlorophyll content, and chlorophyll a fluorescence. A thorough analysis of the root system will clarify carbon dynamics and hydraulics at the whole-plant level, improving final yield predictions.

Ontogenetic functional diversity: size structure of a keystone predator drives functioning of a complex ecosystem.

Science.gov (United States)

Rudolf, Volker H W; Rasmussen, Nick L

2013-05-01

functional roles are dynamic and will change with shifts in the stage structure of the species. In general this emphasizes the importance of accounting for functional diversity below the species level to predict how natural and anthropogenic changes alter the functioning of natural ecosystems.

No consistent effect of plant species richness on resistance to simulated climate change for above- or below-ground processes in managed grasslands.

Science.gov (United States)

Dormann, Carsten F; von Riedmatten, Lars; Scherer-Lorenzen, Michael

2017-06-17

Species richness affects processes and functions in many ecosystems. Since management of temperate grasslands is directly affecting species composition and richness, it can indirectly govern how systems respond to fluctuations in environmental conditions. Our aim in this study was to investigate whether species richness in managed grasslands can buffer the effects of drought and warming manipulations and hence increase the resistance to climate change. We established 45 plots in three regions across Germany, each with three different management regimes (pasture, meadow and mown pasture). We manipulated spring warming using open-top chambers and summer drought using rain-out shelters for 4 weeks. Measurements of species richness, above- and below-ground biomass and soil carbon and nitrogen concentrations showed significant but inconsistent differences among regions, managements and manipulations. We detected a three-way interaction between species richness, management and region, indicating that our study design was sensitive enough to detect even intricate effects. We could not detect a pervasive effect of species richness on biomass differences between treatments and controls, indicating that a combination of spring warming and summer drought effects on grassland systems are not consistently moderated by species richness. We attribute this to the relatively high number of species even at low richness levels, which already provides the complementarity required for positive biodiversity-ecosystem functioning relationships. A review of the literature also indicates that climate manipulations largely fail to show richness-buffering, while natural experiments do, suggesting that such manipulations are milder than reality or incur treatment artefacts.

Dynamics of radon-222 near below ground surface

International Nuclear Information System (INIS)

Fukui, Masami; Katsurayama, Kousuke; Nishimura, Susumu.

1986-01-01

The concentrations and variation of 222 Rn were investigated both in unconfined groundwater and in the aerated zone to obtain information as to the behavior of Rn close to ground surface. The Rn concentrations in unconfined groundwater near the surface were depletive by the extent of about 50 % compared with that of lower part in a borehole, then the continuous extraction of groundwater causes pronounced increase of the concentration. The method, which monitors continuously the Rn concentration in such surroundings, was developed, where the unconfined groundwater extracted was injected into another borehole and sprayed gas was measured using an ionization chamber. The read-out values of this system well followed the variation of concentrations caused by the meteorological parameter, especially infiltrating water. The increase of 222 Rn concentration in the aerated zone above the water level was clearly observed following the ascendant of groundwater level caused by the infiltrating water, whereas the change of concentration in soil air just below the ground surface obeyed mainly to the wetness of soil and unconfined groundwater level rather than atmospheric pressure. (author)

Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis.

Science.gov (United States)

Chen, Hao; Li, Dejun; Gurmesa, Geshere A; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

2015-11-01

Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ecosystem functional response across precipitation extremes in a sagebrush steppe.

Science.gov (United States)

Tredennick, Andrew T; Kleinhesselink, Andrew R; Taylor, J Bret; Adler, Peter B

2018-01-01

Precipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes over the long-term may shift with precipitation means and variances. Long-term changes in ecosystem functional response could reflect compensatory changes in species composition or species reaching physiological thresholds at extreme precipitation levels. We conducted a five year precipitation manipulation experiment in a sagebrush steppe ecosystem in Idaho, United States. We used drought and irrigation treatments (approximately 50% decrease/increase) to investigate whether ecosystem functional response remains consistent under sustained high or low precipitation. We recorded data on aboveground net primary productivity (ANPP), species abundance, and soil moisture. We fit a generalized linear mixed effects model to determine if the relationship between ANPP and soil moisture differed among treatments. We used nonmetric multidimensional scaling to quantify community composition over the five years. Ecosystem functional response, defined as the relationship between soil moisture and ANPP, was similar among irrigation and control treatments, but the drought treatment had a greater slope than the control treatment. However, all estimates for the effect of soil moisture on ANPP overlapped zero, indicating the relationship is weak and uncertain regardless of treatment. There was also large spatial variation in ANPP within-years, which contributes to the uncertainty of the soil moisture effect. Plant community composition was remarkably stable over the course of the experiment and did not differ among treatments. Despite some evidence that ecosystem functional response became more sensitive under sustained drought conditions, the response

Plants as green phones: Novel insights into plant-mediated communication between below- and above-ground insects.

Science.gov (United States)

Soler, Roxina; Harvey, Jeffrey A; Bezemer, T Martijn; Stuefer, Josef F

2008-08-01

Plants can act as vertical communication channels or 'green phones' linking soil-dwelling insects and insects in the aboveground ecosystem. When root-feeding insects attack a plant, the direct defense system of the shoot is activated, leading to an accumulation of phytotoxins in the leaves. The protection of the plant shoot elicited by root damage can impair the survival, growth and development of aboveground insect herbivores, thereby creating plant-based functional links between soil-dwelling insects and insects that develop in the aboveground ecosystem. The interactions between spatially separated insects below- and aboveground are not restricted to root and foliar plant-feeding insects, but can be extended to higher trophic levels such as insect parasitoids. Here we discuss some implications of plants acting as communication channels or 'green phones' between root and foliar-feeding insects and their parasitoids, focusing on recent findings that plants attacked by root-feeding insects are significantly less attractive for the parasitoids of foliar-feeding insects.

A below-ground herbivore shapes root defensive chemistry in natural plant populations.

Science.gov (United States)

Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

2016-03-30

Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. © 2016 The Author(s).

Tropical Andean ecosystems and the need to keep warming limits below a +1.5°C threshold

Science.gov (United States)

Ruiz-Carrascal, D.; Herzog, S. K.; Guitierrez Lagoueyte, M. E.; Gonzalez-Duque, D.; Cuevas-Moreno, J.; del Valle, J. I.; Andreu-Hayles, L.; Herrera, D. A.; Martínez, R.

2017-12-01

Long-term climate change and rapid land-use change are synergistically threatening the integrity and functioning of tropical Andean ecosystems. The main goal of our research was to integrate climate change projections, biodiversity data and anthropogenically driven ecosystem disruption assessments to quantify the vulnerability of Andean ecosystems and species to global change at a local scale. We merged discernible trends in local quality-controlled weather station data with reanalysis data, as well as with historical and prospective simulation outputs of five well-known GCMs to assess a long-term context for the analysis of climate change exposure (temperature severity intervals). Individual, medium-term, multi-member GCM simulations included: altitude-corrected 2046-2065 (IPCC-AR4) climate change scenarios for the A1B emission scenario; and spatially-downscaled 2040-2069 (IPCC-AR5) projections for the RCP4.5. Previous studies reported mean annual temperature anomaly intervals that resulted in exceedingly high thresholds: the lowest severity interval ( +2.71°C). The least severe interval extended up to the threshold widely recognized as `dangerous' climate change, thereby leading to an underestimation of the true vulnerability of Andean species. Our analyses suggest that temperature anomalies for the full extent of the tropical Andes will likely range from low ( +2.61°C), exceeding the threshold of 'natural' climate variability (+1.78°C). Our results suggest that most species that were used as proxies of ecosystem vulnerabilities will likely experience overall low-to-medium-to-high temperature increases. Since many of them have potentially high sensitivity to such long-term changes, Andean species will likely experience greatly increases in vulnerability. The already-disrupted Andean ecosystems will suffer a further climatic stress, which will worsen the well-known detrimental synergies between climate and land-use changes. There is an imperative need to

Climate, soil and plant functional types as drivers of global fine-root trait variation

NARCIS (Netherlands)

Freschet, Grégoire T.; Valverde-Barrantes, Oscar J.; Tucker, Caroline M.; Craine, Joseph M.; McCormack, M. Luke; Violle, Cyrille; Fort, Florian; Blackwood, Christopher B.; Urban-Mead, Katherine R.; Iversen, Colleen M.; Bonis, Anne; Comas, Louise H.; Cornelissen, Johannes H.C.; Dong, Ming; Guo, Dali; Hobbie, Sarah E.; Holdaway, Robert J.; Kembel, Steven W.; Makita, Naoki; Onipchenko, Vladimir G.; Picon-Cochard, Catherine; Reich, Peter B.; de la Riva, Enrique G.; Smith, Stuart W.; Soudzilovskaia, Nadejda A.; Tjoelker, Mark G.; Wardle, David A.; Roumet, Catherine

2017-01-01

Ecosystem functioning relies heavily on below-ground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and

Supplementing forest ecosystem health projects on the ground

Science.gov (United States)

Cathy Barbouletos; Lynette Z. Morelan

1995-01-01

Understanding the functions and processes of ecosystems is critical before implementing forest ecosystem health projects on the landscape. Silvicultural treatments such as thinning, prescribed fire, and reforestation can simulate disturbance regimes and landscape patterns that have regulated forest ecosystems for centuries. As land managers we need to understand these...

Biodiversity and Resilience of Ecosystem Functions.

Science.gov (United States)

Oliver, Tom H; Heard, Matthew S; Isaac, Nick J B; Roy, David B; Procter, Deborah; Eigenbrod, Felix; Freckleton, Rob; Hector, Andy; Orme, C David L; Petchey, Owen L; Proença, Vânia; Raffaelli, David; Suttle, K Blake; Mace, Georgina M; Martín-López, Berta; Woodcock, Ben A; Bullock, James M

2015-11-01

Accelerating rates of environmental change and the continued loss of global biodiversity threaten functions and services delivered by ecosystems. Much ecosystem monitoring and management is focused on the provision of ecosystem functions and services under current environmental conditions, yet this could lead to inappropriate management guidance and undervaluation of the importance of biodiversity. The maintenance of ecosystem functions and services under substantial predicted future environmental change (i.e., their 'resilience') is crucial. Here we identify a range of mechanisms underpinning the resilience of ecosystem functions across three ecological scales. Although potentially less important in the short term, biodiversity, encompassing variation from within species to across landscapes, may be crucial for the longer-term resilience of ecosystem functions and the services that they underpin. Copyright © 2015 Elsevier Ltd. All rights reserved.

Combined effects of agrochemicals and ecosystem services on crop yield across Europe

NARCIS (Netherlands)

Gagic, Vesna; Kleijn, David; Báldi, András; Boros, Gergely; Jørgensen, Helene Bracht; Elek, Zoltán; Garratt, Michael P. D.; de Groot, G. Arjen; Hedlund, Katarina; Kovács- Hostyánszki, Anikó; Marini, Lorenzo; Martin, Emily; Pevere, Ines; Potts, Simon G.; Redlich, Sarah; Senapathi, Deepa; Steffan-Dewenter, Ingolf; Świtek, Stanislaw; Smith, Henrik G.; Takács, Viktória; Tryjanowski, Piotr; van der Putten, Wim H.; van Gils, Stijn; Bommarco, Riccardo

2017-01-01

Simultaneously enhancing ecosystem services provided by biodiversity below and above ground is recommended to reduce dependence on chemical pesticides and mineral fertilisers in agriculture. However, consequences for crop yield have been poorly evaluated. Above ground, increased landscape complexity

Mapping Above- and Below-Ground Carbon Pools in Boreal Forests: The Case for Airborne Lidar.

Science.gov (United States)

Kristensen, Terje; Næsset, Erik; Ohlson, Mikael; Bolstad, Paul V; Kolka, Randall

2015-01-01

A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and spatial distribution of C pools within and among multilayered Norway spruce (Picea abies) stands. Predictor variables from lidar derived metrics delivered precise models of above- and below-ground tree C, which comprised the largest C pool in our study stands. We also found evidence that lidar canopy data correlated well with the variation in field layer C stock, consisting mainly of ericaceous dwarf shrubs and herbaceous plants. However, lidar metrics derived directly from understory echoes did not yield significant models. Furthermore, our results indicate that the variation in both the mosses and soil organic layer C stock plots appears less influenced by differences in stand structure properties than topographical gradients. By using topographical models from lidar ground returns we were able to establish a strong correlation between lidar data and the organic layer C stock at a stand level. Increasing the topographical resolution from plot averages (~2000 m2) towards individual grid cells (1 m2) did not yield consistent models. Our study demonstrates a connection between the size and distribution of different forest C pools and models derived from airborne lidar data, providing a foundation for future research concerning the use of lidar for assessing and monitoring boreal forest C.

Below- and above-ground effects of deadwood and termites in plantation forests

Science.gov (United States)

Michael D. Ulyshen; Richard Shefferson; Scott Horn; Melanie K. Taylor; Bryana Bush; Cavell Brownie; Sebastian Seibold; Michael S. Strickland

2017-01-01

Deadwood is an important legacy structure in managed forests, providing continuity in shelter and resource availability for many organisms and acting as a vehicle by which nutrients can be passed from one stand to the next following a harvest. Despite existing at the interface between below- and above-ground systems, however, much remains unknown about the role woody...

The roots of diversity: below ground species richness and rooting distributions in a tropical forest revealed by DNA barcodes and inverse modeling.

Directory of Open Access Journals (Sweden)

F Andrew Jones

Full Text Available Plants interact with each other, nutrients, and microbial communities in soils through extensive root networks. Understanding these below ground interactions has been difficult in natural systems, particularly those with high plant species diversity where morphological identification of fine roots is difficult. We combine DNA-based root identification with a DNA barcode database and above ground stem locations in a floristically diverse lowland tropical wet forest on Barro Colorado Island, Panama, where all trees and lianas >1 cm diameter have been mapped to investigate richness patterns below ground and model rooting distributions.DNA barcode loci, particularly the cpDNA locus trnH-psba, can be used to identify fine and small coarse roots to species. We recovered 33 species of roots from 117 fragments sequenced from 12 soil cores. Despite limited sampling, we recovered a high proportion of the known species in the focal hectare, representing approximately 14% of the measured woody plant richness. This high value is emphasized by the fact that we would need to sample on average 13 m(2 at the seedling layer and 45 m(2 for woody plants >1 cm diameter to obtain the same number of species above ground. Results from inverse models parameterized with the locations and sizes of adults and the species identifications of roots and sampling locations indicates a high potential for distal underground interactions among plants.DNA barcoding techniques coupled with modeling approaches should be broadly applicable to studying root distributions in any mapped vegetation plot. We discuss the implications of our results and outline how second-generation sequencing technology and environmental sampling can be combined to increase our understanding of how root distributions influence the potential for plant interactions in natural ecosystems.

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning.

Science.gov (United States)

He, Zhili; Zhang, Ping; Wu, Linwei; Rocha, Andrea M; Tu, Qichao; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D; Wu, Liyou; Yang, Yunfeng; Elias, Dwayne A; Watson, David B; Adams, Michael W W; Fields, Matthew W; Alm, Eric J; Hazen, Terry C; Adams, Paul D; Arkin, Adam P; Zhou, Jizhong

2018-02-20

Contamination from anthropogenic activities has significantly impacted Earth's biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly ( P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. IMPORTANCE Disentangling the relationships between biodiversity and ecosystem functioning is an important but poorly understood topic in ecology. Predicting ecosystem functioning on the basis of biodiversity is even more difficult, particularly with microbial biomarkers. As an exploratory effort, this study used key microbial functional genes as biomarkers to provide predictive understanding of environmental contamination and ecosystem functioning. The results indicated that the overall functional gene richness/diversity decreased as uranium increased in groundwater, while specific key microbial guilds increased significantly as

Links between plant litter chemistry, species diversity, and below-ground ecosystem function

OpenAIRE

Meier, Courtney L.; Bowman, William D.

2008-01-01

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics...

EnviroAtlas - Below Ground Live Tree Biomass Carbon Storage for the Conterminous United States- Forested

Data.gov (United States)

U.S. Environmental Protection Agency — This EnviroAtlas dataset includes the average below ground live tree root dry biomass estimate for the Watershed Boundary Dataset (WBD) 12-digit Hydrologic Unit...

Successful range-expanding plants experience less above-ground and below-ground enemy impact.

Science.gov (United States)

Engelkes, Tim; Morriën, Elly; Verhoeven, Koen J F; Bezemer, T Martijn; Biere, Arjen; Harvey, Jeffrey A; McIntyre, Lauren M; Tamis, Wil L M; van der Putten, Wim H

2008-12-18

Many species are currently moving to higher latitudes and altitudes. However, little is known about the factors that influence the future performance of range-expanding species in their new habitats. Here we show that range-expanding plant species from a riverine area were better defended against shoot and root enemies than were related native plant species growing in the same area. We grew fifteen plant species with and without non-coevolved polyphagous locusts and cosmopolitan, polyphagous aphids. Contrary to our expectations, the locusts performed more poorly on the range-expanding plant species than on the congeneric native plant species, whereas the aphids showed no difference. The shoot herbivores reduced the biomass of the native plants more than they did that of the congeneric range expanders. Also, the range-expanding plants developed fewer pathogenic effects in their root-zone soil than did the related native species. Current predictions forecast biodiversity loss due to limitations in the ability of species to adjust to climate warming conditions in their range. Our results strongly suggest that the plants that shift ranges towards higher latitudes and altitudes may include potential invaders, as the successful range expanders may experience less control by above-ground or below-ground enemies than the natives.

Towards a Stochastic Predictive Understanding of Ecosystem Functioning and Resilience to Environmental Changes

Science.gov (United States)

Pappas, C.

2017-12-01

Terrestrial ecosystem processes respond differently to hydrometeorological variability across timescales, and so does our scientific understanding of the underlying mechanisms. Process-based modeling of ecosystem functioning is therefore challenging, especially when long-term predictions are envisioned. Here we analyze the statistical properties of hydrometeorological and ecosystem variability, i.e., the variability of ecosystem process related to vegetation carbon dynamics, from hourly to decadal timescales. 23 extra-tropical forest sites, covering different climatic zones and vegetation characteristics, are examined. Micrometeorological and reanalysis data of precipitation, air temperature, shortwave radiation and vapor pressure deficit are used to describe hydrometeorological variability. Ecosystem variability is quantified using long-term eddy covariance flux data of hourly net ecosystem exchange of CO2 between land surface and atmosphere, monthly remote sensing vegetation indices, annual tree-ring widths and above-ground biomass increment estimates. We find that across sites and timescales ecosystem variability is confined within a hydrometeorological envelope that describes the range of variability of the available resources, i.e., water and energy. Furthermore, ecosystem variability demonstrates long-term persistence, highlighting ecological memory and slow ecosystem recovery rates after disturbances. We derive an analytical model, combining deterministic harmonics and stochastic processes, that represents major mechanisms and uncertainties and mimics the observed pattern of hydrometeorological and ecosystem variability. This stochastic framework offers a parsimonious and mathematically tractable approach for modelling ecosystem functioning and for understanding its response and resilience to environmental changes. Furthermore, this framework reflects well the observed ecological memory, an inherent property of ecosystem functioning that is currently not

Trophic interactions, ecosystem structure and function in the southern Yellow Sea

Science.gov (United States)

Lin, Qun; Jin, Xianshi; Zhang, Bo

2013-01-01

The southern Yellow Sea is an important fishing ground, providing abundant fishery resources. However, overfishing and climate change have caused a decline in the resource and damaged the ecosystem. We developed an ecosystem model to analyze the trophic interactions and ecosystem structure and function to guide sustainable development of the ecosystem. A trophic mass-balance model of the southern Yellow Sea during 2000-2001 was constructed using Ecopath with Ecosim software. We defined 22 important functional groups and studied their diet composition. The trophic levels of fish, shrimp, crabs, and cephalopods were between 2.78 and 4.39, and the mean trophic level of the fisheries was 3.24. The trophic flows within the food web occurred primarily in the lower trophic levels. The mean trophic transfer efficiency was 8.1%, of which 7.1% was from primary producers and 9.3% was from detritus within the ecosystem. The transfer efficiency between trophic levels II to III to IV to V to >V was 5.0%, 5.7%, 18.5%, and 19.7%-20.4%, respectively. Of the total flow, phytoplankton contributed 61% and detritus contributed 39%. Fishing is defined as a top predator within the ecosystem, and has a negative impact on most commercial species. Moreover, the ecosystem had a high gross efficiency of the fishery and a high value of primary production required to sustain the fishery. Together, our data suggest there is high fishing pressure in the southern Yellow Sea. Based on analysis of Odum's ecological parameters, this ecosystem was at an immature stage. Our results provide some insights into the structure and development of this ecosystem.

Ecosystem Functions across Trophic Levels Are Linked to Functional and Phylogenetic Diversity

Science.gov (United States)

Thompson, Patrick L.; Davies, T. Jonathan; Gonzalez, Andrew

2015-01-01

In experimental systems, it has been shown that biodiversity indices based on traits or phylogeny can outperform species richness as predictors of plant ecosystem function. However, it is unclear whether this pattern extends to the function of food webs in natural ecosystems. Here we tested whether zooplankton functional and phylogenetic diversity explains the functioning of 23 natural pond communities. We used two measures of ecosystem function: (1) zooplankton community biomass and (2) phytoplankton abundance (Chl a). We tested for diversity-ecosystem function relationships within and across trophic levels. We found a strong correlation between zooplankton diversity and ecosystem function, whereas local environmental conditions were less important. Further, the positive diversity-ecosystem function relationships were more pronounced for measures of functional and phylogenetic diversity than for species richness. Zooplankton and phytoplankton biomass were best predicted by different indices, suggesting that the two functions are dependent upon different aspects of diversity. Zooplankton community biomass was best predicted by zooplankton trait-based functional richness, while phytoplankton abundance was best predicted by zooplankton phylogenetic diversity. Our results suggest that the positive relationship between diversity and ecosystem function can extend across trophic levels in natural environments, and that greater insight into variation in ecosystem function can be gained by combining functional and phylogenetic diversity measures. PMID:25693188

Impacts of Jatropha-based biodiesel production on above and below-ground carbon stocks: A case study from Mozambique

International Nuclear Information System (INIS)

Vang Rasmussen, Laura; Rasmussen, Kjeld; Bech Bruun, Thilde

2012-01-01

The need to mitigate climate change makes production of liquid biofuels a high priority. Substituting fossil fuels by biodiesel produced from Jatropha curcas has gained widespread attention as Jatropha cultivation is claimed to offer green house gas emission reductions. Farmers respond worldwide to this increasing demand by converting forests into Jatropha, but whether Jatropha-based biodiesel offers carbon savings depends on the carbon emissions that occur when land use is changed to Jatropha. This paper provides an impact assessment of a small-scale Jatropha project in Cabo Delgado, Mozambique. The paper outlines the estimated impacts on above and below-ground carbon stocks when land use is changed to increase Jatropha production. The results show that expansion of Jatropha production will most likely lead to the conversion of miombo forest areas to Jatropha, which implies a reduction in above and below-ground carbon stocks. The carbon debts created by the land use change can be repaid by replacing fossil fuels with Jatropha-based biodiesel. A repayment time of almost two centuries is found with optimistic estimates of the carbon debt, while the use of pessimistic values results in a repayment time that approaches the millennium. - Highlights: ► Demands for biofuels make production of Jatropha-based biodiesel a priority. ► Farmers in Northern Mozambique are likely to convert un-logged miombo to Jatropha. ► Converting miombo to Jatropha creates reductions in above and below-ground carbon. ► It takes 187–966 years to repay emissions from above and below-ground carbon stocks.

Root herbivory indirectly affects above- and below-ground community members and directly reduces plant performance

NARCIS (Netherlands)

Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.

2015-01-01

There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

Science.gov (United States)

Zhang, Ping; Wu, Linwei; Rocha, Andrea M.; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D.; Wu, Liyou; Watson, David B.; Adams, Michael W. W.; Alm, Eric J.; Adams, Paul D.; Arkin, Adam P.

2018-01-01

ABSTRACT Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly (P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. PMID:29463661

Effect of ecosystems substitutions and CO{sub 2} increase of the atmosphere on the microbial ecosystems of forests; Effet de substitutions d'essence et de l'augmentation en CO{sub 2} de l'atmosphere sur les communautes microbiennes intervenant dans le fonctionnement d'un ecosysteme forestier

Energy Technology Data Exchange (ETDEWEB)

Martin, F

2007-07-01

Biological diversity is often exclusively considered at the level of plants and animals, whereas the bulk of global biodiversity is in fact at the microbial level. Although it is clear that the ecology of our planet is driven by microbial ecosystems, we are severely hampered by our limited understanding of the diversity and function of such microbial ecosystems. In the present project, teams in the disciplines of geochemistry, soil microbiology, genomics and ecosystem processes are assembled to study the relationship between environmental change, land use changes, biodiversity, and functioning of forest ecosystems. The network has a strong focus on developing and applying biochemical and genotyping methodologies to address key scientific issues in soil microbial ecology. These include assessing the impact of environmental- and land use changes on microbial diversity and function and exploring the evolutionary and mechanistic links between biological diversity and ecosystem function. In the present study, we have shown that: (1) The native mixed forest showed the highest microbial diversity (2) The mono specific plantations of tree species (e.g., oak, beech, pine, spruce) strikingly alter genetic and functional diversities of soil bacterial and fungal species. (3) Bacterial denitrification rates were dramatically modified by the planted species. Only by taking into account the impact of forest management on below-ground microbial diversity can one hope to get a full ecosystem-based understanding, and this must be addressed via modelling in order to provide relevant and useful information for conservation and policy making. (author)

Distributional (in)congruence of biodiversity-ecosystem functioning

NARCIS (Netherlands)

Mulder, C.; Boit, A.; Mori, S.; Vonk, J.A.; Dyer, S.D.; Faggiano, L.; Geisen, S.; González, A.L.; Kaspari, M.; Lavorel, S.; Marquet, P.A.; Rossberg, A.G.; Sterner, R.W.; Voigt, W.; Wall, D.H.

2012-01-01

The majority of research on biodiversity-ecosystem functioning in laboratories has concentrated on a few traits, but there is increasing evidence from the field that functional diversity controls ecosystem functioning more often than does species number. Given the importance of traits as predictors

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

Directory of Open Access Journals (Sweden)

Zhili He

2018-02-01

Full Text Available Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN, representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5 increased significantly (P < 0.05 as uranium or nitrate increased, and their changes could be used to successfully predict uranium and nitrate contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning.

Effects of red-backed salamanders on ecosystem functions.

Directory of Open Access Journals (Sweden)

Daniel J Hocking

Full Text Available Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp. likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2 plots and small-scale enclosures (2 m(2 where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2. In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders. Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

Effects of red-backed salamanders on ecosystem functions.

Science.gov (United States)

Hocking, Daniel J; Babbitt, Kimberly J

2014-01-01

Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp.) likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus) on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2) plots) and small-scale enclosures (2 m(2)) where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2)). In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders). Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

Integrating community assembly and biodiversity to better understand ecosystem function: the Community Assembly and the Functioning of Ecosystems (CAFE) approach.

Science.gov (United States)

Bannar-Martin, Katherine H; Kremer, Colin T; Ernest, S K Morgan; Leibold, Mathew A; Auge, Harald; Chase, Jonathan; Declerck, Steven A J; Eisenhauer, Nico; Harpole, Stanley; Hillebrand, Helmut; Isbell, Forest; Koffel, Thomas; Larsen, Stefano; Narwani, Anita; Petermann, Jana S; Roscher, Christiane; Cabral, Juliano Sarmento; Supp, Sarah R

2018-02-01

The research of a generation of ecologists was catalysed by the recognition that the number and identity of species in communities influences the functioning of ecosystems. The relationship between biodiversity and ecosystem functioning (BEF) is most often examined by controlling species richness and randomising community composition. In natural systems, biodiversity changes are often part of a bigger community assembly dynamic. Therefore, focusing on community assembly and the functioning of ecosystems (CAFE), by integrating both species richness and composition through species gains, losses and changes in abundance, will better reveal how community changes affect ecosystem function. We synthesise the BEF and CAFE perspectives using an ecological application of the Price equation, which partitions the contributions of richness and composition to function. Using empirical examples, we show how the CAFE approach reveals important contributions of composition to function. These examples show how changes in species richness and composition driven by environmental perturbations can work in concert or antagonistically to influence ecosystem function. Considering how communities change in an integrative fashion, rather than focusing on one axis of community structure at a time, will improve our ability to anticipate and predict changes in ecosystem function. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

β-Diversity, Community Assembly, and Ecosystem Functioning.

Science.gov (United States)

Mori, Akira S; Isbell, Forest; Seidl, Rupert

2018-05-25

Evidence is increasing for positive effects of α-diversity on ecosystem functioning. We highlight here the crucial role of β-diversity - a hitherto underexplored facet of biodiversity - for a better process-level understanding of biodiversity change and its consequences for ecosystems. A focus on β-diversity has the potential to improve predictions of natural and anthropogenic influences on diversity and ecosystem functioning. However, linking the causes and consequences of biodiversity change is complex because species assemblages in nature are shaped by many factors simultaneously, including disturbance, environmental heterogeneity, deterministic niche factors, and stochasticity. Because variability and change are ubiquitous in ecosystems, acknowledging these inherent properties of nature is an essential step for further advancing scientific knowledge of biodiversity-ecosystem functioning in theory and practice. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Functional Responses and Resilience of Boreal Forest Ecosystem after Reduction of Deer Density

Science.gov (United States)

Bachand, Marianne; Pellerin, Stéphanie; Moretti, Marco; Aubin, Isabelle; Tremblay, Jean-Pierre; Côté, Steeve D.; Poulin, Monique

2014-01-01

The functional trait-based approach is increasingly used to predict responses of ecological communities to disturbances, but most studies target a single taxonomic group. Here, we assessed the resilience of a forest ecosystem to an overabundant herbivore population by assessing changes in 19 functional traits for plant, 13 traits for ground beetle and 16 traits for songbird communities after six years of controlled browsing on Anticosti Island (Quebec, Canada). Our results indicated that plants were more responsive to 6 years of reduced browsing pressure than ground beetles and songbirds. However, co-inertia analysis revealed that ground beetle communities responded in a similar way than plant communities with stronger relationships between plant and ground beetle traits at reduced deer density, a pattern not detected between plant and songbird. High deer density favored plants species that reproduce vegetatively and with abiotic pollination and seed dispersal, traits implying little interaction with animal. On the other hand, traits found at reduced deer density mostly involved trophic interaction. For example, plants in this treatment had fleshy fruits and large seeds dispersed by birds or other animals whereas ground beetle species were carnivorous. Overall, our results suggest that plant communities recovered some functional components to overabundant herbivore populations, since most traits associated with undisturbed forests were reestablished after six years of deer reduction. The re-establishment of functional plant communities with traits involving trophic interaction induces changes in the ground-beetle trait community, but forest structure remains likely insufficiently heterogeneous to shift the songbird trait community within six years. PMID:24587362

Functional responses and resilience of boreal forest ecosystem after reduction of deer density.

Directory of Open Access Journals (Sweden)

Marianne Bachand

Full Text Available The functional trait-based approach is increasingly used to predict responses of ecological communities to disturbances, but most studies target a single taxonomic group. Here, we assessed the resilience of a forest ecosystem to an overabundant herbivore population by assessing changes in 19 functional traits for plant, 13 traits for ground beetle and 16 traits for songbird communities after six years of controlled browsing on Anticosti Island (Quebec, Canada. Our results indicated that plants were more responsive to 6 years of reduced browsing pressure than ground beetles and songbirds. However, co-inertia analysis revealed that ground beetle communities responded in a similar way than plant communities with stronger relationships between plant and ground beetle traits at reduced deer density, a pattern not detected between plant and songbird. High deer density favored plants species that reproduce vegetatively and with abiotic pollination and seed dispersal, traits implying little interaction with animal. On the other hand, traits found at reduced deer density mostly involved trophic interaction. For example, plants in this treatment had fleshy fruits and large seeds dispersed by birds or other animals whereas ground beetle species were carnivorous. Overall, our results suggest that plant communities recovered some functional components to overabundant herbivore populations, since most traits associated with undisturbed forests were reestablished after six years of deer reduction. The re-establishment of functional plant communities with traits involving trophic interaction induces changes in the ground-beetle trait community, but forest structure remains likely insufficiently heterogeneous to shift the songbird trait community within six years.

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...

Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host-parasite interactions.

Science.gov (United States)

Tao, Leiling; Gowler, Camden D; Ahmad, Aamina; Hunter, Mark D; de Roode, Jacobus C

2015-10-22

Host-parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host-parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host-parasite systems. © 2015 The Author(s).

Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host–parasite interactions

Science.gov (United States)

Tao, Leiling; Gowler, Camden D.; Ahmad, Aamina; Hunter, Mark D.; de Roode, Jacobus C.

2015-01-01

Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems. PMID:26468247

Plant species and functional group combinations affect green roof ecosystem functions.

Science.gov (United States)

Lundholm, Jeremy; Macivor, J Scott; Macdougall, Zachary; Ranalli, Melissa

2010-03-12

Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green

ABOVE AND BELOW GROUND INTERACTIONS IN THE AGROFORESTAL ASSOCIATION 'RED CEDAR-PERSIAN LIME-CHAYA'

Directory of Open Access Journals (Sweden)

Jesús Mao Estanislao Aguilar-Luna

2011-05-01

Full Text Available Above and below ground interactions were analyzed in the agroforestal association 'red cedar-Persian lime-chaya', to know the initial optimum planting density (PD, in Quintana Roo, Mexico. Red cedar and Persian lime were placed in a 'Nelder' circle of 3154 m2 which consisted of 20 concentric circles alternating red cedars and Persian limes to 1.50 m apart and 10 plants per circle; chaya rectangular frame was set at 1.50 x 3.00 m, superimposed on the 'Nelder' circle. Defined eight PD 2602 to 3772 pl·ha-1 with 10 repetitions, to evaluate the length of main root (LMR, radical exploration range (RER, below ground interaction (BGI, plant height (PH, crown diameter (CD, above ground interaction (AGI and soil fertility (SF. The growth intraspecific he present statistical difference (P≤0.05 when moving from one PD to another PD, while the growth interespecific manifested different growth habit. The agroforestal association propitious in soil decreased phosphorous ±2 %, and increases organic matter ±14 % and nitrogen ±10 % on all PD. The BGI was increased in direct relation with the PD, reaching its highest value (64±5.8 % to 3772 pl·ha-1; the AGI also increased in direct relation with the PD, its highest value (52±3.1 % went to 3772 pl·ha-1; therefore, to higher PD increased BGI and AGI, at 20 months after planting.

Is the energy density of the ground state of the sine-Gordon model unbounded from below for β2 > 8π?

International Nuclear Information System (INIS)

Faber, M; Ivanov, A N

2003-01-01

We discuss Coleman's theorem concerning the energy density of the ground state of the sine-Gordon model proved in Coleman S (1975 Phys. Rev. D 11 2088). According to this theorem the energy density of the ground state of the sine-Gordon model should be unbounded from below for coupling constants β 2 > 8π. The consequence of this theorem would be the non-existence of the quantum ground state of the sine-Gordon model for β 2 > 8π. We show that the energy density of the ground state in the sine-Gordon model is bounded from below even for β 2 > 8π. This result is discussed in relation to Coleman's theorem (Coleman S 1973 Commun. Math. Phys. 31 259), particle mass spectra and soliton-soliton scattering in the sine-Gordon model

Leaf bacterial diversity mediates plant diversity and ecosystem function relationships.

Science.gov (United States)

Laforest-Lapointe, Isabelle; Paquette, Alain; Messier, Christian; Kembel, Steven W

2017-06-01

Research on biodiversity and ecosystem functioning has demonstrated links between plant diversity and ecosystem functions such as productivity. At other trophic levels, the plant microbiome has been shown to influence host plant fitness and function, and host-associated microbes have been proposed to influence ecosystem function through their role in defining the extended phenotype of host organisms However, the importance of the plant microbiome for ecosystem function has not been quantified in the context of the known importance of plant diversity and traits. Here, using a tree biodiversity-ecosystem functioning experiment, we provide strong support for the hypothesis that leaf bacterial diversity is positively linked to ecosystem productivity, even after accounting for the role of plant diversity. Our results also show that host species identity, functional identity and functional diversity are the main determinants of leaf bacterial community structure and diversity. Our study provides evidence of a positive correlation between plant-associated microbial diversity and terrestrial ecosystem productivity, and a new mechanism by which models of biodiversity-ecosystem functioning relationships can be improved.

Rare species support vulnerable functions in high-diversity ecosystems.

Science.gov (United States)

Mouillot, David; Bellwood, David R; Baraloto, Christopher; Chave, Jerome; Galzin, Rene; Harmelin-Vivien, Mireille; Kulbicki, Michel; Lavergne, Sebastien; Lavorel, Sandra; Mouquet, Nicolas; Paine, C E Timothy; Renaud, Julien; Thuiller, Wilfried

2013-01-01

Around the world, the human-induced collapses of populations and species have triggered a sixth mass extinction crisis, with rare species often being the first to disappear. Although the role of species diversity in the maintenance of ecosystem processes has been widely investigated, the role of rare species remains controversial. A critical issue is whether common species insure against the loss of functions supported by rare species. This issue is even more critical in species-rich ecosystems where high functional redundancy among species is likely and where it is thus often assumed that ecosystem functioning is buffered against species loss. Here, using extensive datasets of species occurrences and functional traits from three highly diverse ecosystems (846 coral reef fishes, 2,979 alpine plants, and 662 tropical trees), we demonstrate that the most distinct combinations of traits are supported predominantly by rare species both in terms of local abundance and regional occupancy. Moreover, species that have low functional redundancy and are likely to support the most vulnerable functions, with no other species carrying similar combinations of traits, are rarer than expected by chance in all three ecosystems. For instance, 63% and 98% of fish species that are likely to support highly vulnerable functions in coral reef ecosystems are locally and regionally rare, respectively. For alpine plants, 32% and 89% of such species are locally and regionally rare, respectively. Remarkably, 47% of fish species and 55% of tropical tree species that are likely to support highly vulnerable functions have only one individual per sample on average. Our results emphasize the importance of rare species conservation, even in highly diverse ecosystems, which are thought to exhibit high functional redundancy. Rare species offer more than aesthetic, cultural, or taxonomic diversity value; they disproportionately increase the potential breadth of functions provided by ecosystems across

Functional traits in agriculture: agrobiodiversity and ecosystem services.

Science.gov (United States)

Wood, Stephen A; Karp, Daniel S; DeClerck, Fabrice; Kremen, Claire; Naeem, Shahid; Palm, Cheryl A

2015-09-01

Functional trait research has led to greater understanding of the impacts of biodiversity in ecosystems. Yet, functional trait approaches have not been widely applied to agroecosystems and understanding of the importance of agrobiodiversity remains limited to a few ecosystem processes and services. To improve this understanding, we argue here for a functional trait approach to agroecology that adopts recent advances in trait research for multitrophic and spatially heterogeneous ecosystems. We suggest that trait values should be measured across environmental conditions and agricultural management regimes to predict how ecosystem services vary with farm practices and environment. This knowledge should be used to develop management strategies that can be easily implemented by farmers to manage agriculture to provide multiple ecosystem services. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis.

Science.gov (United States)

Yue, Kai; Peng, Yan; Peng, Changhui; Yang, Wanqin; Peng, Xin; Wu, Fuzhong

2016-01-27

Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition.

Application of remote sensing data for measuring freshwater ecosystems changes below the Zeya dam in the Russian Far East

Science.gov (United States)

Nikitina, Oxana I.; Bazarov, Kirill Y.; Egidarev, Evgeny G.

2018-06-01

The large Zeya hydropower dam is located on the Zeya River, the largest left-bank tributary of the Amur-Heilong River in Russia. The dam had been constructed by 1980 and its operation has significantly transformed the flow regime of the Zeya River. The flow regulation has reduced the magnitude of periodic flooding of the floodplain areas located downstream from the Zeya dam and disrupted habitats of flora and fauna. An estimation of the transformation of the freshwater ecosystems is required to develop measures necessary either to maintain or restore disrupted ecosystems. Application of remote sensing methods allows measuring characteristics of the ecosystem's components. Two sections of a floodplain below the Zeya dam were considered for analysis in order to detect changes in objects at each site during the comparison of remote data from 1969/1971 and 2016.

Rare species support vulnerable functions in high-diversity ecosystems.

Directory of Open Access Journals (Sweden)

David Mouillot

Full Text Available Around the world, the human-induced collapses of populations and species have triggered a sixth mass extinction crisis, with rare species often being the first to disappear. Although the role of species diversity in the maintenance of ecosystem processes has been widely investigated, the role of rare species remains controversial. A critical issue is whether common species insure against the loss of functions supported by rare species. This issue is even more critical in species-rich ecosystems where high functional redundancy among species is likely and where it is thus often assumed that ecosystem functioning is buffered against species loss. Here, using extensive datasets of species occurrences and functional traits from three highly diverse ecosystems (846 coral reef fishes, 2,979 alpine plants, and 662 tropical trees, we demonstrate that the most distinct combinations of traits are supported predominantly by rare species both in terms of local abundance and regional occupancy. Moreover, species that have low functional redundancy and are likely to support the most vulnerable functions, with no other species carrying similar combinations of traits, are rarer than expected by chance in all three ecosystems. For instance, 63% and 98% of fish species that are likely to support highly vulnerable functions in coral reef ecosystems are locally and regionally rare, respectively. For alpine plants, 32% and 89% of such species are locally and regionally rare, respectively. Remarkably, 47% of fish species and 55% of tropical tree species that are likely to support highly vulnerable functions have only one individual per sample on average. Our results emphasize the importance of rare species conservation, even in highly diverse ecosystems, which are thought to exhibit high functional redundancy. Rare species offer more than aesthetic, cultural, or taxonomic diversity value; they disproportionately increase the potential breadth of functions provided by

Integrating community assembly and biodiversity to better understand ecosystem function: the Community Assembly and the Functioning of Ecosystems (CAFE) approach

NARCIS (Netherlands)

Bannar-Martin, K.; Kremer, C.; Ernest, S.K. Morgan; Leibold, M.; Auge, H.; Chase, J.; Declerck, S.A.J.; Eisenhauer, Nico; Harpole, W.S.; Hillebrand, H.; Isbell, F.; Koffel, T.; Larsen, S.; Narwani, A.; Petermann, J.; Roscher, C.; Sarmento Cabral, J.; Supp, S.

2018-01-01

The research of a generation of ecologists was catalysed by the recognition that the number and identity of species in communities influences the functioning of ecosystems. The relationship between biodiversity and ecosystem functioning (BEF) is most often examined by controlling species richness

Grazing management that regenerates ecosystem function and ...

African Journals Online (AJOL)

Grazing management that regenerates ecosystem function and grazingland ... in ecosystem improvement, productivity, soil carbon and fertility, water-holding ... for sufficient time to produce resource improvement, sound animal production, and ...

Linking Ecosystem Services Benefit Transfer Databases and Ecosystem Services Production Function Libraries

Science.gov (United States)

The quantification or estimation of the economic and non-economic values of ecosystem services can be done from a number of distinct approaches. For example, practitioners may use ecosystem services production function models (ESPFMs) for a particular location, or alternatively, ...

Thermal regulation of functional groups in running water ecosystems. Progress report, 1974--1975

International Nuclear Information System (INIS)

Cummins, K.W.; Klug, M.J.

1975-01-01

Upper and lower thermal limits and temperature dependent growth were determined for a number of organisms (or populations) representing various functional groups of stream ecosystems (microconsumers, producers, and macroconsumers, shredders, collectors, scrapers, and predators). Although temperature functions as an overall control parameter, organic substrate (microconsumers) and inorganic nutrients (microconsumers and producers), light (producers) and food quality (macroconsumers) can modify thermal responses. Stream microorganisms typically grow below their thermal optima, community composition being determined by those that can manage the maximum growth at a given temperature utilizing a given organic substrate. Producers in first to third order streams are generally light limited (although nutrient availability is also important). Food quality, primarily a function of microbial biomass in the case of detritivores. can compensate for temperature dependent growth in non-predator macroinvertebrate functional groups. (U.S.)

Functional ecomorphology: Feedbacks between form and function in fluvial landscape ecosystems

Science.gov (United States)

Fisher, Stuart G.; Heffernan, James B.; Sponseller, Ryan A.; Welter, Jill R.

2007-09-01

The relationship between form and function has been a central organizing principle in biology throughout its history as a formal science. This concept has been relevant from molecules to organisms but loses meaning at population and community levels where study targets are abstract collectives and assemblages. Ecosystems include organisms and abiotic factors but ecosystem ecology too has developed until recently without a strong spatially explicit reference. Landscape ecology provides an opportunity to once again anneal form and function and to consider reciprocal causation between them. This ecomorphologic view can be applied at a variety of ecologically relevant scales and consists of an investigation of how geomorphology provides a structural template that shapes, and is shaped by ecological processes. Running water ecosystems illustrate several principles governing the interaction of landscape form and ecological function subsumed by the concept of "Functional Ecomorphology". Particularly lucrative are ecosystem-level interactions between geologic form and biogeochemical processes integrated by hydrologic flowpaths. While the utility of a flowpath-based approach is most apparent in streams, spatially explicit biogeochemical processing pervades all landscapes and may be of general ecological application.

A COMPARATIVE ANALYSIS OF SPECIES COMPOSITION OF GROUND BEETLES OF COASTAL AND ISLAND ECOSYSTEMS OF THE WESTERN CASPIAN

Directory of Open Access Journals (Sweden)

G. M. Abdurakhmanov

2011-01-01

Full Text Available For the first time studied the species composition of ground beetles of coastal and island ecosystems of the Western Caspian. The article provides a comparative analysis of species composition of ground beetles and adjacent areas.

Biodiversity of arbuscular mycorrhizal fungi and ecosystem function.

Science.gov (United States)

Powell, Jeff R; Rillig, Matthias C

2018-03-30

Contents Summary I. pathways of influence and pervasiveness of effects II. AM fungal richness effects on ecosystem functions III. Other dimensions of biodiversity IV. Back to basics - primary axes of niche differentiation by AM fungi V. Functional diversity of AM fungi - a role for biological stoichiometry? VI. Past, novel and future ecosystems VII. Opportunities and the way forward Acknowledgements References SUMMARY: Arbuscular mycorrhizal (AM) fungi play important functional roles in ecosystems, including the uptake and transfer of nutrients, modification of the physical soil environment and alteration of plant interactions with other biota. Several studies have demonstrated the potential for variation in AM fungal diversity to also affect ecosystem functioning, mainly via effects on primary productivity. Diversity in these studies is usually characterized in terms of the number of species, unique evolutionary lineages or complementary mycorrhizal traits, as well as the ability of plants to discriminate among AM fungi in space and time. However, the emergent outcomes of these relationships are usually indirect, and thus context dependent, and difficult to predict with certainty. Here, we advocate a fungal-centric view of AM fungal biodiversity-ecosystem function relationships that focuses on the direct and specific links between AM fungal fitness and consequences for their roles in ecosystems, especially highlighting functional diversity in hyphal resource economics. We conclude by arguing that an understanding of AM fungal functional diversity is fundamental to determine whether AM fungi have a role in the exploitation of marginal/novel environments (whether past, present or future) and highlight avenues for future research. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Multi-functional landscapes in semi arid environments: implications for biodiversity and ecosystem services

CSIR Research Space (South Africa)

O'Farrell, PJ

2010-06-01

Full Text Available assessment with an ecosystem service assessment. Stakeholder engagement and expert consultation focussed our investigations on surface water, ground water, grazing and tourism as the key services in this region. The key ecosystem services and service hotspots...

Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China

DEFF Research Database (Denmark)

Chen, Hao; Li, Dejun; Gurmesa, Geshere Abdisa

2015-01-01

Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling...... and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle....

Regional zooplankton dispersal provides spatial insurance for ecosystem function.

Science.gov (United States)

Symons, Celia C; Arnott, Shelley E

2013-05-01

Changing environmental conditions are affecting diversity and ecosystem function globally. Theory suggests that dispersal from a regional species pool may buffer against changes in local community diversity and ecosystem function after a disturbance through the establishment of functionally redundant tolerant species. The spatial insurance provided by dispersal may decrease through time after environmental change as the local community monopolizes resources and reduces community invasibility. To test for evidence of the spatial insurance hypothesis and to determine the role dispersal timing plays in this response we conducted a field experiment using crustacean zooplankton communities in a subarctic region that is expected to be highly impacted by climate change - Churchill, Canada. Three experiments were conducted where nutrients, salt, and dispersal were manipulated. The three experiments differed in time-since-disturbance that the dispersers were added. We found that coarse measures of diversity (i.e. species richness, evenness, and Shannon-Weiner diversity) were generally resistant to large magnitude disturbances, and that dispersal had the most impact on diversity when dispersers were added shortly after disturbance. Ecosystem functioning (chl-a) was degraded in disturbed communities, but dispersal recovered ecosystem function to undisturbed levels. This spatial insurance for ecosystem function was mediated through changes in community composition and the relative abundance of functional groups. Results suggest that regional diversity and habitat connectivity will be important in the future to maintain ecosystem function by introducing functionally redundant species to promote compensatory dynamics. © 2012 Blackwell Publishing Ltd.

Functional redundancy and food web functioning in linuron-exposed ecosystems

Energy Technology Data Exchange (ETDEWEB)

De Laender, F., E-mail: frederik.delaender@ugent.be [Laboratory of Environmental Toxicity and Aquatic Ecology, Ghent University, Plateaustraat 22, 9000 Ghent (Belgium); Van den Brink, P.J., E-mail: Paul.vandenBrink@wur.nl [Department of Aquatic Ecology and Water Quality Management, Wageningen University, PO Box 47, 6700 AA Wageningen (Netherlands); Janssen, C.R., E-mail: colin.janssen@ugent.be [Laboratory of Environmental Toxicity and Aquatic Ecology, Ghent University, Plateaustraat 22, 9000 Ghent (Belgium)

2011-10-15

An extensive data set describing effects of the herbicide linuron on macrophyte-dominated microcosms was analysed with a food web model to assess effects on ecosystem functioning. We showed that sensitive phytoplankton and periphyton groups in the diets of heterotrophs were gradually replaced by more tolerant phytoplankton species as linuron concentrations increased. This diet shift - showing redundancy among phytoplankton species - allowed heterotrophs to maintain their functions in the contaminated microcosms. On an ecosystem level, total gross primary production was up to hundred times lower in the treated microcosms but the uptake of dissolved organic carbon by bacteria and mixotrophs was less sensitive. Food web efficiency was not consistently lower in the treated microcosms. We conclude that linuron predominantly affected the macrophytes but did not alter the overall functioning of the surrounding planktonic food web. Therefore, a risk assessment that protects macrophyte growth also protects the functioning of macrophyte-dominated microcosms. - Highlights: > Food web modelling reveals the functional response of species and ecosystem to linuron. > Primary production was more sensitive to linuron than bacterial production. > Linuron replaced sensitive phytoplankton by tolerant phytoplankton in heterotrophs' diets. > Linuron did not change the functioning of heterotrophs. - Food web modelling reveals functional redundancy of the planktonic community in microcosms treated with linuron.

Functional redundancy and food web functioning in linuron-exposed ecosystems

International Nuclear Information System (INIS)

De Laender, F.; Van den Brink, P.J.; Janssen, C.R.

2011-01-01

An extensive data set describing effects of the herbicide linuron on macrophyte-dominated microcosms was analysed with a food web model to assess effects on ecosystem functioning. We showed that sensitive phytoplankton and periphyton groups in the diets of heterotrophs were gradually replaced by more tolerant phytoplankton species as linuron concentrations increased. This diet shift - showing redundancy among phytoplankton species - allowed heterotrophs to maintain their functions in the contaminated microcosms. On an ecosystem level, total gross primary production was up to hundred times lower in the treated microcosms but the uptake of dissolved organic carbon by bacteria and mixotrophs was less sensitive. Food web efficiency was not consistently lower in the treated microcosms. We conclude that linuron predominantly affected the macrophytes but did not alter the overall functioning of the surrounding planktonic food web. Therefore, a risk assessment that protects macrophyte growth also protects the functioning of macrophyte-dominated microcosms. - Highlights: → Food web modelling reveals the functional response of species and ecosystem to linuron. → Primary production was more sensitive to linuron than bacterial production. → Linuron replaced sensitive phytoplankton by tolerant phytoplankton in heterotrophs' diets. → Linuron did not change the functioning of heterotrophs. - Food web modelling reveals functional redundancy of the planktonic community in microcosms treated with linuron.

Speciation below ground: Tempo and mode of diversification in a radiation of endogean ground beetles.

Science.gov (United States)

Andújar, Carmelo; Pérez-González, Sergio; Arribas, Paula; Zaballos, Juan P; Vogler, Alfried P; Ribera, Ignacio

2017-11-01

Dispersal is a critical factor determining the spatial scale of speciation, which is constrained by the ecological characteristics and distribution of a species' habitat and the intrinsic traits of species. Endogean taxa are strongly affected by the unique qualities of the below-ground environment and its effect on dispersal, and contrasting reports indicate either high dispersal capabilities favoured by small body size and mediated by passive mechanisms, or low dispersal due to restricted movement and confinement inside the soil. We studied a species-rich endogean ground beetle lineage, Typhlocharina, including three genera and more than 60 species, as a model for the evolutionary biology of dispersal and speciation in the deep soil. A time-calibrated molecular phylogeny generated from >400 individuals was used to delimit candidate species, to study the accumulation of lineages through space and time by species-area-age relationships and to determine the geographical structure of the diversification using the relationship between phylogenetic and geographic distances across the phylogeny. Our results indicated a small spatial scale of speciation in Typhlocharina and low dispersal capacity combined with sporadic long distance, presumably passive dispersal events that fuelled the speciation process. Analysis of lineage growth within Typhlocharina revealed a richness plateau correlated with the range of distribution of lineages, suggesting a long-term species richness equilibrium mediated by density dependence through limits of habitat availability. The interplay of area- and age-dependent processes ruling the lineage diversification in Typhlocharina may serve as a general model for the evolution of high species diversity in endogean mesofauna. © 2017 John Wiley & Sons Ltd.

Epiphyte-cover on seagrass (Zostera marina L. leaves impedes plant performance and radial O2 loss from the below-ground tissue

Directory of Open Access Journals (Sweden)

Kasper Elgetti Brodersen

2015-08-01

Full Text Available The O2 budget of seagrasses is a complex interaction between several sources and sinks, which is strongly regulated by light availability and mass transfer over the diffusive boundary layer (DBL surrounding the plant. Epiphyte growth on leaves may thus strongly affect the O2 availability of the seagrass plant and its capability to aerate its rhizosphere as a defence against plant toxins.We used electrochemical and fiber-optic microsensors to quantify the O2 flux, DBL and light microclimate around leaves with and without filamentous algal epiphytes. We also quantified the below-ground radial O2 loss from roots (~1 mm from the root-apex to elucidate how this below-ground oxic microzone was affected by the presence of epiphytes.Epiphyte-cover on seagrass leaves (~21% areal cover resulted in reduced light quality and quantity for photosynthesis, thus leading to reduced plant fitness. A ~4 times thicker diffusive boundary layer around leaves with epiphyte-cover impeded gas (and nutrient exchange with the surrounding water-column and thus the amount of O2 passively diffusing into the leaves in darkness. During light exposure of the leaves, radial oxygen loss from the below-ground tissue was ~2 times higher from plants without epiphyte-cover. In contrast, no O2 was detectable at the surface of the root-cap tissue of plants with epiphyte-cover during darkness, leaving the plants more susceptible to sulphide intrusion.Epiphyte growth on seagrass leaves thus negatively affects the light climate and O2 uptake in darkness, hampering the plants performance and thereby reducing the oxidation capability of its below-ground tissue.

Maximum entropy models of ecosystem functioning

International Nuclear Information System (INIS)

Bertram, Jason

2014-01-01

Using organism-level traits to deduce community-level relationships is a fundamental problem in theoretical ecology. This problem parallels the physical one of using particle properties to deduce macroscopic thermodynamic laws, which was successfully achieved with the development of statistical physics. Drawing on this parallel, theoretical ecologists from Lotka onwards have attempted to construct statistical mechanistic theories of ecosystem functioning. Jaynes’ broader interpretation of statistical mechanics, which hinges on the entropy maximisation algorithm (MaxEnt), is of central importance here because the classical foundations of statistical physics do not have clear ecological analogues (e.g. phase space, dynamical invariants). However, models based on the information theoretic interpretation of MaxEnt are difficult to interpret ecologically. Here I give a broad discussion of statistical mechanical models of ecosystem functioning and the application of MaxEnt in these models. Emphasising the sample frequency interpretation of MaxEnt, I show that MaxEnt can be used to construct models of ecosystem functioning which are statistical mechanical in the traditional sense using a savanna plant ecology model as an example

Maximum entropy models of ecosystem functioning

Energy Technology Data Exchange (ETDEWEB)

Bertram, Jason, E-mail: jason.bertram@anu.edu.au [Research School of Biology, The Australian National University, Canberra ACT 0200 (Australia)

2014-12-05

Using organism-level traits to deduce community-level relationships is a fundamental problem in theoretical ecology. This problem parallels the physical one of using particle properties to deduce macroscopic thermodynamic laws, which was successfully achieved with the development of statistical physics. Drawing on this parallel, theoretical ecologists from Lotka onwards have attempted to construct statistical mechanistic theories of ecosystem functioning. Jaynes’ broader interpretation of statistical mechanics, which hinges on the entropy maximisation algorithm (MaxEnt), is of central importance here because the classical foundations of statistical physics do not have clear ecological analogues (e.g. phase space, dynamical invariants). However, models based on the information theoretic interpretation of MaxEnt are difficult to interpret ecologically. Here I give a broad discussion of statistical mechanical models of ecosystem functioning and the application of MaxEnt in these models. Emphasising the sample frequency interpretation of MaxEnt, I show that MaxEnt can be used to construct models of ecosystem functioning which are statistical mechanical in the traditional sense using a savanna plant ecology model as an example.

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.

Effects of declining oak vitality on ecosystem functions: Lessons from a Spanish oak woodland

Science.gov (United States)

López-Sánchez, Aida; Bareth, Georg; Bolten, Andreas; Linstädter, Anja

2017-04-01

characteristics such as the received radiation of the hydrological year, slope, aspect, soil depth, grazing offtake, as well as the cover of bare ground and litter. The geo-morphological data comes from a high resolution UAV generated digital elevation model. We used GLMMs and LMMs to assess effects of tree health on ecosystem functions, statistically controlling for plots' variable environmental conditions. We found ANPP to be higher in intercanopy habitats and beneath trees with a low vigor or crown density. In contrast, highly vigorous trees increased legume biomass and grass biomass. Responses of other ecosystem functions were mostly not significant, although a lower diversity was found under trees with intermediate vigor. In the case of MEFHI, we assume that positive and negative responses have partly masked each other. Our results underline that a NOD-related decline in tree vitality has complex effects on ecosystem functions. For example, it increases forage quantity but decreases forage quality. Ecosystem functions under trees with a low vigor were in most cases similar to those in adjacent open habitats, showing that the presence of vigorous (i.e. old and vital) trees is critical for maintaining ecosystem functions on a landscape level. Keywords: NODs, dehesa, ANNP, decomposition, herb diversity, habitat degradation

Carbon sequestration capacity in a semiarid ecosystem: A carbon balance approach

International Nuclear Information System (INIS)

Almagro, M.; Lopez, J.; Boix-Fayos, C.; Albaladejo, J.; Martinez-Mena, M.

2009-01-01

Here, we used two C balance approaches to estimate total below ground C allocation (TBCA) in three representative land uses in a Mediterranean ecosystem (late-successional forest, abandoned agricultural field, rainfed olive grove). Our objectives were: 1) to asses the response of TBCA and its components to changes in land use; 2) to evaluate how soil water erosion and changes in C stored in roots, soil and litter layer altered our estimates of TBCA; 3) to determine annual net ecosystem productivity, and examine C allocation patterns at each land use. (Author) 4 refs.

Quantifying effects of biodiversity on ecosystem functioning across times and places†

Science.gov (United States)

Isbell, Forest; Cowles, Jane; Dee, Laura E.; Loreau, Michel; Reich, Peter B.; Gonzalez, Andrew; Hector, Andy; Schmid, Bernhard

2018-01-01

Biodiversity loss decreases ecosystem functioning at the local scales at which species interact, but it remains unclear how biodiversity loss affects ecosystem functioning at the larger scales of space and time that are most relevant to biodiversity conservation and policy. Theory predicts that additional insurance effects of biodiversity on ecosystem functioning could emerge across time and space if species respond asynchronously to environmental variation and if species become increasingly dominant when and where they are most productive. Even if only a few dominant species maintain ecosystem functioning within a particular time and place, ecosystem functioning may be enhanced by many different species across many times and places (β-diversity). Here, we develop and apply a new approach to estimate these previously unquantified insurance effects of biodiversity on ecosystem functioning that arise due to species turnover across times and places. In a long-term (18-year) grassland plant diversity experiment, we find that total insurance effects are positive in sign and substantial in magnitude, amounting to 19% of the net biodiversity effect, mostly due to temporal insurance effects. Species loss can therefore reduce ecosystem functioning both locally and by eliminating species that would otherwise enhance ecosystem functioning across temporally fluctuating and spatially heterogeneous environments. PMID:29493062

Structural and functional loss in restored wetland ecosystems.

Directory of Open Access Journals (Sweden)

David Moreno-Mateos

2012-01-01

Full Text Available Wetlands are among the most productive and economically valuable ecosystems in the world. However, because of human activities, over half of the wetland ecosystems existing in North America, Europe, Australia, and China in the early 20th century have been lost. Ecological restoration to recover critical ecosystem services has been widely attempted, but the degree of actual recovery of ecosystem functioning and structure from these efforts remains uncertain. Our results from a meta-analysis of 621 wetland sites from throughout the world show that even a century after restoration efforts, biological structure (driven mostly by plant assemblages, and biogeochemical functioning (driven primarily by the storage of carbon in wetland soils, remained on average 26% and 23% lower, respectively, than in reference sites. Either recovery has been very slow, or postdisturbance systems have moved towards alternative states that differ from reference conditions. We also found significant effects of environmental settings on the rate and degree of recovery. Large wetland areas (>100 ha and wetlands restored in warm (temperate and tropical climates recovered more rapidly than smaller wetlands and wetlands restored in cold climates. Also, wetlands experiencing more (riverine and tidal hydrologic exchange recovered more rapidly than depressional wetlands. Restoration performance is limited: current restoration practice fails to recover original levels of wetland ecosystem functions, even after many decades. If restoration as currently practiced is used to justify further degradation, global loss of wetland ecosystem function and structure will spread.

New insights into the ground thermal regime of talus slopes with permafrost below the timberline

Science.gov (United States)

Schwindt, Daniel; Kneisel, Christof

2013-04-01

In the central Alps permafrost can be expected above 2400 m a.s.l., at altitudes where mean annual air temperatures are below -1° C. However, isolated permafrost occurrences are present in north-exposed talus slopes, far below the timberline, where mean annual air temperatures are positive. Driving factors are assumed to be a low income of solar radiation, a thick organic layer with high insulation capacities as well as the thermally induced chimney effect (Wakonigg, 1996). Investigated are three talus slopes with permafrost in the Swiss Alps that differ with regard to elevation level, talus material, humus characteristics and vegetation composition as well as the mean annual air temperatures. Aim is to achieve a deeper understanding of the factors determining the site-specific thermal regime, as well as the spatially limited and temporally highly variable permafrost occurrences in vegetated talus slopes. Focus is not solely on the question of why permafrost exists at these sites, but also why permafrost does not exist in the immediate surroundings. To detect the temporal variability and spatial heterogeneity of the permafrost occurrences, electrical resistivity tomography monitoring, seismic refraction tomography monitoring, and quasi-3D ERT were applied. To determine the ground thermal regime, air-, ground surface-, and humus temperatures, as well as temperatures within vents of the chimneys were recorded. Furthermore, humus characteristics (thickness, -temperature and -moisture) were mapped in permafrost-affected slope areas and in the immediate surroundings. To test the correlation between solar radiation, permafrost distribution, and humus/vegetation composition, digital elevation models were used to calculate the income of solar radiation. The areal extent of the permafrost bodies coincide precisely with slope sections where the organic layer is thickest, a consistent moss cover is present, and where temperatures at the transition between humus layer and

Bacterial biodiversity-ecosystem functioning relations are modified by environmental complexity.

Science.gov (United States)

Langenheder, Silke; Bulling, Mark T; Solan, Martin; Prosser, James I

2010-05-26

With the recognition that environmental change resulting from anthropogenic activities is causing a global decline in biodiversity, much attention has been devoted to understanding how changes in biodiversity may alter levels of ecosystem functioning. Although environmental complexity has long been recognised as a major driving force in evolutionary processes, it has only recently been incorporated into biodiversity-ecosystem functioning investigations. Environmental complexity is expected to strengthen the positive effect of species richness on ecosystem functioning, mainly because it leads to stronger complementarity effects, such as resource partitioning and facilitative interactions among species when the number of available resource increases. Here we implemented an experiment to test the combined effect of species richness and environmental complexity, more specifically, resource richness on ecosystem functioning over time. We show, using all possible combinations of species within a bacterial community consisting of six species, and all possible combinations of three substrates, that diversity-functioning (metabolic activity) relationships change over time from linear to saturated. This was probably caused by a combination of limited complementarity effects and negative interactions among competing species as the experiment progressed. Even though species richness and resource richness both enhanced ecosystem functioning, they did so independently from each other. Instead there were complex interactions between particular species and substrate combinations. Our study shows clearly that both species richness and environmental complexity increase ecosystem functioning. The finding that there was no direct interaction between these two factors, but that instead rather complex interactions between combinations of certain species and resources underlie positive biodiversity ecosystem functioning relationships, suggests that detailed knowledge of how individual

Bacterial biodiversity-ecosystem functioning relations are modified by environmental complexity.

Directory of Open Access Journals (Sweden)

Silke Langenheder

Full Text Available BACKGROUND: With the recognition that environmental change resulting from anthropogenic activities is causing a global decline in biodiversity, much attention has been devoted to understanding how changes in biodiversity may alter levels of ecosystem functioning. Although environmental complexity has long been recognised as a major driving force in evolutionary processes, it has only recently been incorporated into biodiversity-ecosystem functioning investigations. Environmental complexity is expected to strengthen the positive effect of species richness on ecosystem functioning, mainly because it leads to stronger complementarity effects, such as resource partitioning and facilitative interactions among species when the number of available resource increases. METHODOLOGY/PRINCIPAL FINDINGS: Here we implemented an experiment to test the combined effect of species richness and environmental complexity, more specifically, resource richness on ecosystem functioning over time. We show, using all possible combinations of species within a bacterial community consisting of six species, and all possible combinations of three substrates, that diversity-functioning (metabolic activity relationships change over time from linear to saturated. This was probably caused by a combination of limited complementarity effects and negative interactions among competing species as the experiment progressed. Even though species richness and resource richness both enhanced ecosystem functioning, they did so independently from each other. Instead there were complex interactions between particular species and substrate combinations. CONCLUSIONS/SIGNIFICANCE: Our study shows clearly that both species richness and environmental complexity increase ecosystem functioning. The finding that there was no direct interaction between these two factors, but that instead rather complex interactions between combinations of certain species and resources underlie positive biodiversity

Carbon transfer from photosynthesis to below ground fine root/hyphae respiration in Quercus serrata using stable carbon isotope pulse labeling

Science.gov (United States)

Dannoura, M.; Kominami, Y.; Takanashi, S.; Takahashi, K.

2013-12-01

Studying carbon allocation in trees is a key to better understand belowground carbon cycle and its response to climate change. Tracing 13C in tree and soil compartments after pulse labeling is one of powerful tool to study the fate of carbon in forest ecosystems. This experiment was conducted in Yamashiro experimental forest, Kyoto, Japan. Annual mean temperature and precipitation from 1994 to 2009 are 15.5 ° C and 1,388 mm respectively. The branch pulse labeling were done 7 times in 2011 using same branch of Quercus serrata (H:11.7 m, DBH; 33.7 cm) to see seasonal variations of carbon velocity. Whole crown labeling of Quercus serrata (H:9 m, DBH; 13.7 cm) was done in 2012 to study carbon allocation and to especially focus on belowground carbon flux until to the hyphae respiration. Pure 13CO2 (99.9%) was injected to the labeling chamber which was set to branch or crown. Then, after one hour of branch labeling and 3.5 hour for crown labeling, the chamber was opened. Trunk respiration chambers, fine root chambers and hyphae chambers were set to the target tree to trace labeled carbon in the CO2 efflux. 41 μm mesh was used to exclude ingrowth of roots into hyphae chambers. The results show that the velocity of carbon through the tree varied seasonally, with higher velocity in summer than autumn, averaging 0.47 m h-1. Half-lives of labeled carbon in autotrophic respiration were similar above and below ground during the growing season, but they were twice longer in trunk than in root in autumn. From the whole crown labeling done end of growing season, the 13CO2 signal was observed 25 hours after labeling in trunk chamber and 34-37.7 hours after labeling in fine root and hyphae respiration almost simultaneously. Half-lives of 13 was longer in trunk than below ground. Trunk respiration was still using labelled carbon during winter suggesting that winter trunk respiration is partly fueled by carbon stored in the trunk at the end of the growing season.

Cowpea N rhizodeposition and its below-ground transfer to a co-existing and to a subsequent millet crop on a sandy soil of the Sudano-Sahelian eco-zone

DEFF Research Database (Denmark)

Laberge, Guillaume; Haussmann, Bettina I.G.; Ambus, Per

2011-01-01

Nitrogen (N) rhizodeposition by cowpea (Vigna unguiculata (L.) Walp) is potentially a large N source in cropping systems of Sub-Saharan Africa. A field experiment was conducted to measure cowpea N rhizodeposition under the conditions of the Sudano-Sahelian zone using direct 15N labelling techniques...... to trace the amount of deposition and its transfer to associated and subsequent crops. Half of the total cowpea crop N was located below-ground at plant maturity, which exceeded 20 kg N ha−1 when intercropped with millet. Only 15% of the below-ground cowpea N was recovered in roots, while 85% was found...... in the rhizodeposited pools. The experiment demonstrated that direct below-ground N transfer occurred from cowpea to millet in intercrop at a rate of 2 kg N ha−1 over the growing season. Forty percent of the 25 kg below-ground N that the cowpea crop left at harvest were identifiable in the top 0.30 m soil...

Ecosystem functioning is enveloped by hydrometeorological variability.

Science.gov (United States)

Pappas, Christoforos; Mahecha, Miguel D; Frank, David C; Babst, Flurin; Koutsoyiannis, Demetris

2017-09-01

Terrestrial ecosystem processes, and the associated vegetation carbon dynamics, respond differently to hydrometeorological variability across timescales, and so does our scientific understanding of the underlying mechanisms. Long-term variability of the terrestrial carbon cycle is not yet well constrained and the resulting climate-biosphere feedbacks are highly uncertain. Here we present a comprehensive overview of hydrometeorological and ecosystem variability from hourly to decadal timescales integrating multiple in situ and remote-sensing datasets characterizing extra-tropical forest sites. We find that ecosystem variability at all sites is confined within a hydrometeorological envelope across sites and timescales. Furthermore, ecosystem variability demonstrates long-term persistence, highlighting ecological memory and slow ecosystem recovery rates after disturbances. However, simulation results with state-of-the-art process-based models do not reflect this long-term persistent behaviour in ecosystem functioning. Accordingly, we develop a cross-time-scale stochastic framework that captures hydrometeorological and ecosystem variability. Our analysis offers a perspective for terrestrial ecosystem modelling and paves the way for new model-data integration opportunities in Earth system sciences.

Functional complexity and ecosystem stability: an experimental approach

Energy Technology Data Exchange (ETDEWEB)

Van Voris, P.; O' Neill, R.V.; Shugart, H.H.; Emanuel, W.R.

1978-01-01

The complexity-stability hypothesis was experimentally tested using intact terrestrial microcosms. Functional complexity was defined as the number and significance of component interactions (i.e., population interactions, physical-chemical reactions, biological turnover rates) influenced by nonlinearities, feedbacks, and time delays. It was postulated that functional complexity could be nondestructively measured through analysis of a signal generated from the system. Power spectral analysis of hourly CO/sub 2/ efflux, from eleven old-field microcosms, was analyzed for the number of low frequency peaks and used to rank the functional complexity of each system. Ranking of ecosystem stability was based on the capacity of the system to retain essential nutrients and was measured by net loss of Ca after the system was stressed. Rank correlation supported the hypothesis that increasing ecosystem functional complexity leads to increasing ecosystem stability. The results indicated that complex functional dynamics can serve to stabilize the system. The results also demonstrated that microcosms are useful tools for system-level investigations.

Diverse effects of invasive ecosystem engineers on marine biodiversity and ecosystem functions: A global review and meta-analysis.

Science.gov (United States)

Guy-Haim, Tamar; Lyons, Devin A; Kotta, Jonne; Ojaveer, Henn; Queirós, Ana M; Chatzinikolaou, Eva; Arvanitidis, Christos; Como, Serena; Magni, Paolo; Blight, Andrew J; Orav-Kotta, Helen; Somerfield, Paul J; Crowe, Tasman P; Rilov, Gil

2018-03-01

Invasive ecosystem engineers (IEE) are potentially one of the most influential types of biological invaders. They are expected to have extensive ecological impacts by altering the physical-chemical structure of ecosystems, thereby changing the rules of existence for a broad range of resident biota. To test the generality of this expectation, we used a global systematic review and meta-analysis to examine IEE effects on the abundance of individual species and communities, biodiversity (using several indices) and ecosystem functions, focusing on marine and estuarine environments. We found that IEE had a significant effect (positive and negative) in most studies testing impacts on individual species, but the overall (cumulative) effect size was small and negative. Many individual studies showed strong IEE effects on community abundance and diversity, but the direction of effects was variable, leading to statistically non-significant overall effects in most categories. In contrast, there was a strong overall effect on most ecosystem functions we examined. IEE negatively affected metabolic functions and primary production, but positively affected nutrient flux, sedimentation and decomposition. We use the results to develop a conceptual model by highlighting pathways whereby IEE impact communities and ecosystem functions, and identify several sources of research bias in the IEE-related invasion literature. Only a few of the studies simultaneously quantified IEE effects on community/diversity and ecosystem functions. Therefore, understanding how IEE may alter biodiversity-ecosystem function relationships should be a primary focus of future studies of invasion biology. Moreover, the clear effects of IEE on ecosystem functions detected in our study suggest that scientists and environmental managers ought to examine how the effects of IEE might be manifested in the services that marine ecosystems provide to humans. © 2017 John Wiley & Sons Ltd.

Can above-ground ecosystem services compensate for reduced fertilizer input and soil organic matter in annual crops?

NARCIS (Netherlands)

van Gils, Stijn; van der Putten, Wim H; Kleijn, David

2016-01-01

1.Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure, and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop

Can above-ground ecosystem services compensate for reduced fertilizer input and soil organic matter in annual crops?

NARCIS (Netherlands)

Gils, van S.H.; Putten, van der W.H.; Kleijn, D.

2016-01-01

1.Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop

Declining resilience of ecosystem functions under biodiversity loss.

Science.gov (United States)

Oliver, Tom H; Isaac, Nick J B; August, Tom A; Woodcock, Ben A; Roy, David B; Bullock, James M

2015-12-08

The composition of species communities is changing rapidly through drivers such as habitat loss and climate change, with potentially serious consequences for the resilience of ecosystem functions on which humans depend. To assess such changes in resilience, we analyse trends in the frequency of species in Great Britain that provide key ecosystem functions--specifically decomposition, carbon sequestration, pollination, pest control and cultural values. For 4,424 species over four decades, there have been significant net declines among animal species that provide pollination, pest control and cultural values. Groups providing decomposition and carbon sequestration remain relatively stable, as fewer species are in decline and these are offset by large numbers of new arrivals into Great Britain. While there is general concern about degradation of a wide range of ecosystem functions, our results suggest actions should focus on particular functions for which there is evidence of substantial erosion of their resilience.

Examination of Below-Ground Structure and Soil Respiration Rates of Stable and Deteriorating Salt Marshes in Jamaica Bay (NY)

Science.gov (United States)

CAT scan imaging is currently being used to examine below-ground peat and root structure in cores collected from salt marshes of Jamaica Bay, part of the Gateway National Recreation Area (NY). CAT scans or Computer-Aided Tomography scans use X-ray equipment to produce multiple i...

Changes in ground beetle assemblages above and below the treeline of the Dolomites after almost 30 years (1980/2009)

OpenAIRE

Pizzolotto, Roberto; Gobbi, Mauro; Brandmayr, Pietro

2014-01-01

Very little is known about the changes of ground beetle assemblages in the last few decades in the Alps, and different responses to climate change of animal populations living above and below the treeline have not been estimated yet. This study focuses on an altitudinal habitat sequence from subalpine spruce forest to alpine grassland in a low disturbance area of the southeastern Dolomites in Italy, the Paneveggio Regional Park. We compared the ground beetle (Carabidae) populations sampled in...

Competitive responses of seedlings and understory plants in longleaf pine woodlands: separating canopy influences above and below ground

Science.gov (United States)

Stephen D. Pecot; Robert J. Mitchell; Brian J. Palik; Barry Moser; J. Kevin Hiers

2007-01-01

A trenching study was used to investigate above- and below-ground competition in a longleaf pine (Pinus palustris P. Mill.) woodland. Trenched and nontrenched plots were replicated in the woodland matrix, at gap edges, and in gap centers representing a range of overstory stocking. One-half of each plot received a herbicide treatment to remove the...

Above- and below-ground competition in high and low irradiance: tree seedling responses to a competing liana Byttneria grandifolia

NARCIS (Netherlands)

Chen, J.Y.; Bongers, F.; Cao, K.F.; Cai, Z.Q.

2008-01-01

Abstract: In tropical forests, trees compete not only with other trees, but also with lianas, which may limit tree growth and regeneration. Liana effects may depend on the availability of above- and below-ground resources and differ between tree species. We conducted a shade house experiment to test

Soil ecosystem functioning under climate change: plant species and community effects

Energy Technology Data Exchange (ETDEWEB)

Kardol, Paul [ORNL; Cregger, Melissa [ORNL; Campany, Courtney E [ORNL; Classen, Aimee T [ORNL

2010-01-01

Feedbacks of terrestrial ecosystems to climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the microbial communities that feed on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and water availability. Specifically, we collected soils at the plot level (plant community soils), and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: 1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activities, and soil nematodes. Multiple climate change factors can interact to shape ecosystems, but in this case, those interactions were largely driven by changes in water availability. 2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning and this impact was not obvious when looking at plant community soils. Climate change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. In sum, these results indicate that accurate assessments of climate change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate change-induced shifts in plant community composition will likely modify or counteract the direct

Unearthing belowground bud banks in fire-prone ecosystems.

Science.gov (United States)

Pausas, Juli G; Lamont, Byron B; Paula, Susana; Appezzato-da-Glória, Beatriz; Fidelis, Alessandra

2018-03-01

Despite long-time awareness of the importance of the location of buds in plant biology, research on belowground bud banks has been scant. Terms such as lignotuber, xylopodium and sobole, all referring to belowground bud-bearing structures, are used inconsistently in the literature. Because soil efficiently insulates meristems from the heat of fire, concealing buds below ground provides fitness benefits in fire-prone ecosystems. Thus, in these ecosystems, there is a remarkable diversity of bud-bearing structures. There are at least six locations where belowground buds are stored: roots, root crown, rhizomes, woody burls, fleshy swellings and belowground caudexes. These support many morphologically distinct organs. Given their history and function, these organs may be divided into three groups: those that originated in the early history of plants and that currently are widespread (bud-bearing roots and root crowns); those that also originated early and have spread mainly among ferns and monocots (nonwoody rhizomes and a wide range of fleshy underground swellings); and those that originated later in history and are strictly tied to fire-prone ecosystems (woody rhizomes, lignotubers and xylopodia). Recognizing the diversity of belowground bud banks is the starting point for understanding the many evolutionary pathways available for responding to severe recurrent disturbances. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Functional approach in estimation of cultural ecosystem services of recreational areas

Science.gov (United States)

Sautkin, I. S.; Rogova, T. V.

2018-01-01

The article is devoted to the identification and analysis of cultural ecosystem services of recreational areas from the different forest plant functional groups in the suburbs of Kazan. The study explored two cultural ecosystem services supplied by forest plants by linking these services to different plant functional traits. Information on the functional traits of 76 plants occurring in the forest ecosystems of the investigated area was collected from reference books on the biological characteristics of plant species. Analysis of these species and traits with the Ward clustering method yielded four functional groups with different potentials for delivering ecosystem services. The results show that the contribution of species diversity to services can be characterized through the functional traits of plants. This proves that there is a stable relationship between biodiversity and the quality and quantity of ecosystem services. The proposed method can be extended to other types of services (regulating and supporting). The analysis can be used in the socio-economic assessment of natural ecosystems for recreation and other uses.

Plant functional types in Earth system models: past experiences and future directions for application of dynamic vegetation models in high-latitude ecosystems.

Science.gov (United States)

Wullschleger, Stan D; Epstein, Howard E; Box, Elgene O; Euskirchen, Eugénie S; Goswami, Santonu; Iversen, Colleen M; Kattge, Jens; Norby, Richard J; van Bodegom, Peter M; Xu, Xiaofeng

2014-07-01

Earth system models describe the physical, chemical and biological processes that govern our global climate. While it is difficult to single out one component as being more important than another in these sophisticated models, terrestrial vegetation is a critical player in the biogeochemical and biophysical dynamics of the Earth system. There is much debate, however, as to how plant diversity and function should be represented in these models. Plant functional types (PFTs) have been adopted by modellers to represent broad groupings of plant species that share similar characteristics (e.g. growth form) and roles (e.g. photosynthetic pathway) in ecosystem function. In this review, the PFT concept is traced from its origin in the early 1800s to its current use in regional and global dynamic vegetation models (DVMs). Special attention is given to the representation and parameterization of PFTs and to validation and benchmarking of predicted patterns of vegetation distribution in high-latitude ecosystems. These ecosystems are sensitive to changing climate and thus provide a useful test case for model-based simulations of past, current and future distribution of vegetation. Models that incorporate the PFT concept predict many of the emerging patterns of vegetation change in tundra and boreal forests, given known processes of tree mortality, treeline migration and shrub expansion. However, representation of above- and especially below-ground traits for specific PFTs continues to be problematic. Potential solutions include developing trait databases and replacing fixed parameters for PFTs with formulations based on trait co-variance and empirical trait-environment relationships. Surprisingly, despite being important to land-atmosphere interactions of carbon, water and energy, PFTs such as moss and lichen are largely absent from DVMs. Close collaboration among those involved in modelling with the disciplines of taxonomy, biogeography, ecology and remote sensing will be

An ecosystem carbon database for Canadian forests

Energy Technology Data Exchange (ETDEWEB)

Shaw, C.H.; Bhatti, J.S.; Sabourin, K.J.

2005-07-01

The forest ecosystem carbon database (FECD) is a compilation of data from more than 700 plots from different forest ecosystems in Canada. It includes more than 60 variables for site, stand and soil characteristics. It is intended for large-scale modelers and analysts working with the carbon budget and dynamics of forest ecosystems, particularly those interested in the response of forest carbon stocks and fluxes to changes in climate and site characteristics. The database includes totals for organic and mineral soil horizons for each plot along with total soil carbon content, tree biomass carbon content by component and total ecosystem carbon content. It is complete for site description information, soil chemistry, stand-level estimates of live tree biomass and carbon components and their totals. Soil carbon content by horizon was also included. The compilation targeted data collected at single points in space, where above ground and below ground carbon levels were measured simultaneously. It was noted that one of the important information gaps lies in the fact that no data was available for the natural disturbance or management histories of the stands where the plots were located. Estimates did not include detrital carbon or root biomass, which can influence the estimates for total ecosystem carbon in some forest types. The preliminary analysis reveals that ecozones can be grouped according to low and high average total biomass carbon content. The groups correlate to ecozones with low and high average total ecosystem carbon. Mineral soil carbon within each group contributes the highest proportion of carbon to the average total ecosystem carbon. It is correlated with a gradient in ecozone climate from cold and dry to warm and wet. 42 refs., 13 tabs., 16 figs.

Explaining plant-soil diversity in Alpine ecosystems: more than just time since ecosystem succession started

Science.gov (United States)

Lane, Stuart; Baetz, Nico; Borgeaud, Laure; Verrecchia, Eric; Vittoz, Pascal

2014-05-01

Ecosystem succession in Alpine environments has been a focus of research for many decades. Following from the classic ideas of Jenny (1941, 1961), following perturbation, an ecosystem (flora, fauna and soil) should evolve as a function of time at a rate conditioned by external variables (relief, climate, geology). More recently, biogeomorphologists have focused upon the notion of co-evolution of geomorphic processes with ecosystems over very short through to very long (evolutionary) time-scales. Alpine environments have been a particular focus of models of co-evolution, as a means of understanding the rate of plant colonization of previously glaciated terrain. However, work in this field has tended to adopt an over simplified view of the relationship between perturbation and succession, including: how the landform and ecosystem itself conditions the impact of a perturbation to create a complex spatial impact; and how perturbations are not simply ecosystem destroyers but can be a significant source of ecosystem resources. What this means is that at the within landform scale, there may well be a complex and dynamic topographic and sedimentological template that co-evolves with the development of soil, flora and fauna. In this paper, we present and test conceptual models for such co-evolution for an Alpine alluvial fan and an Alpine piedmont braided river. We combine detailed floristic inventory with soil inventory, survey of edaphic variables above and below ground (e.g. vertical and lateral sedimentological structure, using electrical resistance tomography) and the analysis of historical aerial imagery. The floristic inventory shows the existence of a suite of distinct plant communities within each landform. Time since last perturbation is not a useful explanatory variable of the spatial distribution of these communities because: (1) perturbation impacts are spatially variable, as conditioned by the extent distribution of topographic, edaphic and ecological

Heavy metal concentrations in ground beetles, leaf litter, and soil of a forest ecosystem.

Science.gov (United States)

Jelaska, Lucija Serić; Blanusa, Maja; Durbesić, Paula; Jelaska, Sven D

2007-01-01

The objective of this study was to quantify the relationships between heavy metal concentrations in soil, leaf litter, and ground beetles at four sampling sites of a forest ecosystem in Medvednica Nature Park, Croatia. Ground beetles were sampled by pitfall trapping. Specimens were dry-ashed and soil and beetle samples digested with nitric acid. Lead, cadmium, copper, zinc, manganese, and iron were analyzed using atomic absorption spectrometry. Statistically significant differences between plots were found for lead, cadmium, and iron in ground beetles. Correlations between ground beetles and soil or leaf litter were positive for lead and cadmium concentrations and negative for iron concentration. Differences in species metal concentrations were recorded. Higher concentrations of all studied metals were found in female beetles. However, a significant difference between sexes was found only for manganese. Significant differences in species metal concentrations were found for species that differ in feeding strategies and age based on breeding season and emergence of young adults.

Alpine ecosystems

Science.gov (United States)

P.W. Rundel; C.I. Millar

2016-01-01

Alpine ecosystems are typically defined as those areas occurring above treeline, while recognizing that alpine ecosystems at a local scale may be found below this boundary for reasons including geology, geomorphology, and microclimate. The lower limit of the alpine ecosystems, the climatic treeline, varies with latitude across California, ranging from about 3500 m in...

Spatial Assessment of Forest Ecosystem Functions and Services using Human Relating Factors for SDG

Science.gov (United States)

Song, C.; Lee, W. K.; Jeon, S. W.; Kim, T.; Lim, C. H.

2015-12-01

Application of ecosystem service concept in environmental related decision making could be numerical and objective standard for policy maker between preserving and developing perspective of environment. However, pursuing maximum benefit from natural capital through ecosystem services caused failure by losing ecosystem functions through its trade-offs. Therefore, difference between ecosystem functions and services were demonstrated and would apply human relating perspectives. Assessment results of ecosystem functions and services can be divided 3 parts. Tree growth per year set as the ecosystem function factor and indicated through so called pure function map. After that, relating functions can be driven such as water conservation, air pollutant purification, climate change regulation, and timber production. Overall process and amount are numerically quantified. These functional results can be transferred to ecosystem services by multiplying economic unit value, so function reflecting service maps can be generated. On the other hand, above services, to implement more reliable human demand, human reflecting service maps are also be developed. As the validation, quantified ecosystem functions are compared with former results through pixel based analysis. Three maps are compared, and through comparing difference between ecosystem function and services and inversed trends in function based and human based service are analysed. In this study, we could find differences in PF, FRS, and HRS in relation to based ecosystem conditions. This study suggests that the differences in PF, FRS, and HRS should be understood in the decision making process for sustainable management of ecosystem services. Although the analysis is based on in sort existing process separation, it is important to consider the possibility of different usage of ecosystem function assessment results and ecosystem service assessment results in SDG policy making. Furthermore, process based functional approach

Indicators of ecosystem function identify alternate states in the sagebrush steppe.

Science.gov (United States)

Kachergis, Emily; Rocca, Monique E; Fernandez-Gimenez, Maria E

2011-10-01

Models of ecosystem change that incorporate nonlinear dynamics and thresholds, such as state-and-transition models (STMs), are increasingly popular tools for land management decision-making. However, few models are based on systematic collection and documentation of ecological data, and of these, most rely solely on structural indicators (species composition) to identify states and transitions. As STMs are adopted as an assessment framework throughout the United States, finding effective and efficient ways to create data-driven models that integrate ecosystem function and structure is vital. This study aims to (1) evaluate the utility of functional indicators (indicators of rangeland health, IRH) as proxies for more difficult ecosystem function measurements and (2) create a data-driven STM for the sagebrush steppe of Colorado, USA, that incorporates both ecosystem structure and function. We sampled soils, plant communities, and IRH at 41 plots with similar clayey soils but different site histories to identify potential states and infer the effects of management practices and disturbances on transitions. We found that many IRH were correlated with quantitative measures of functional indicators, suggesting that the IRH can be used to approximate ecosystem function. In addition to a reference state that functions as expected for this soil type, we identified four biotically and functionally distinct potential states, consistent with the theoretical concept of alternate states. Three potential states were related to management practices (chemical and mechanical shrub treatments and seeding history) while one was related only to ecosystem processes (erosion). IRH and potential states were also related to environmental variation (slope, soil texture), suggesting that there are environmental factors within areas with similar soils that affect ecosystem dynamics and should be noted within STMs. Our approach generated an objective, data-driven model of ecosystem dynamics

Ecosystem Vulnerability Review: Proposal of an Interdisciplinary Ecosystem Assessment Approach

Science.gov (United States)

Weißhuhn, Peter; Müller, Felix; Wiggering, Hubert

2018-06-01

To safeguard the sustainable use of ecosystems and their services, early detection of potentially damaging changes in functional capabilities is needed. To support a proper ecosystem management, the analysis of an ecosystem's vulnerability provide information on its weaknesses as well as on its capacity to recover after suffering an impact. However, the application of the vulnerability concept to ecosystems is still an emerging topic. After providing background on the vulnerability concept, we summarize existing ecosystem vulnerability research on the basis of a systematic literature review with a special focus on ecosystem type, disciplinary background, and more detailed definition of the ecosystem vulnerability components. Using the Web of ScienceTM Core Collection, we overviewed the literature from 1991 onwards but used the 5 years from 2011 to 2015 for an in-depth analysis, including 129 articles. We found that ecosystem vulnerability analysis has been applied most notably in conservation biology, climate change research, and ecological risk assessments, pinpointing a limited spreading across the environmental sciences. It occurred primarily within marine and freshwater ecosystems. To avoid confusion, we recommend using the unambiguous term ecosystem vulnerability rather than ecological, environmental, population, or community vulnerability. Further, common ground has been identified, on which to define the ecosystem vulnerability components exposure, sensitivity, and adaptive capacity. We propose a framework for ecosystem assessments that coherently connects the concepts of vulnerability, resilience, and adaptability as different ecosystem responses. A short outlook on the possible operationalization of the concept by ecosystem vulnerabilty indices, and a conclusion section complete the review.

Rising tides, cumulative impacts and cascading changes to estuarine ecosystem functions.

Science.gov (United States)

O'Meara, Theresa A; Hillman, Jenny R; Thrush, Simon F

2017-08-31

In coastal ecosystems, climate change affects multiple environmental factors, yet most predictive models are based on simple cause-and-effect relationships. Multiple stressor scenarios are difficult to predict because they can create a ripple effect through networked ecosystem functions. Estuarine ecosystem function relies on an interconnected network of physical and biological processes. Estuarine habitats play critical roles in service provision and represent global hotspots for organic matter processing, nutrient cycling and primary production. Within these systems, we predicted functional changes in the impacts of land-based stressors, mediated by changing light climate and sediment permeability. Our in-situ field experiment manipulated sea level, nutrient supply, and mud content. We used these stressors to determine how interacting environmental stressors influence ecosystem function and compared results with data collected along elevation gradients to substitute space for time. We show non-linear, multi-stressor effects deconstruct networks governing ecosystem function. Sea level rise altered nutrient processing and impacted broader estuarine services ameliorating nutrient and sediment pollution. Our experiment demonstrates how the relationships between nutrient processing and biological/physical controls degrade with environmental stress. Our results emphasise the importance of moving beyond simple physically-forced relationships to assess consequences of climate change in the context of ecosystem interactions and multiple stressors.

Biodiversity and ecosystem functioning in evolving food webs.

Science.gov (United States)

Allhoff, K T; Drossel, B

2016-05-19

We use computer simulations in order to study the interplay between biodiversity and ecosystem functioning (BEF) during both the formation and the ongoing evolution of large food webs. A species in our model is characterized by its own body mass, its preferred prey body mass and the width of its potential prey body mass spectrum. On an ecological time scale, population dynamics determines which species are viable and which ones go extinct. On an evolutionary time scale, new species emerge as modifications of existing ones. The network structure thus emerges and evolves in a self-organized manner. We analyse the relation between functional diversity and five community level measures of ecosystem functioning. These are the metabolic loss of the predator community, the total biomasses of the basal and the predator community, and the consumption rates on the basal community and within the predator community. Clear BEF relations are observed during the initial build-up of the networks, or when parameters are varied, causing bottom-up or top-down effects. However, ecosystem functioning measures fluctuate only very little during long-term evolution under constant environmental conditions, despite changes in functional diversity. This result supports the hypothesis that trophic cascades are weaker in more complex food webs. © 2016 The Author(s).

Intertemporal Choice of Marine Ecosystem Exploitation

DEFF Research Database (Denmark)

Ravn-Jonsen, Lars

Management, however, requires models that can link the ecosystem level to the operation level, so this paper examines an ecosystem production model and shows that it is suitable for applying ground rent theory. This model is the simplest possible that incorporates the principles of size as the main......, it is probably detrimental from an economic point of view. The marine ecosystem therefore requires an ecosystem management for economic reasons; in this context, models like the one presented here can serve as useful planning tools....... determinant of the predator--prey interaction, the inclusion of mass balance in the predator--prey allocation, and mortality and somatic growth as consequences of the predator--prey allocation. The model needs to be parameterized for the specific ecosystem and the price and cost functions must be established...

Asynchrony among local communities stabilises ecosystem function of metacommunities

DEFF Research Database (Denmark)

Wilcox, Kevin R.; Tredennick, Andrew T.; Koerner, Sally E.

2017-01-01

Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities...

Extinction order and altered community structure rapidly disrupt ecosystem functioning.

Science.gov (United States)

Larsen, Trond H; Williams, Neal M; Kremen, Claire

2005-05-01

By causing extinctions and altering community structure, anthropogenic disturbances can disrupt processes that maintain ecosystem integrity. However, the relationship between community structure and ecosystem functioning in natural systems is poorly understood. Here we show that habitat loss appeared to disrupt ecosystem functioning by affecting extinction order, species richness and abundance. We studied pollination by bees in a mosaic of agricultural and natural habitats in California and dung burial by dung beetles on recently created islands in Venezuela. We found that large-bodied bee and beetle species tended to be both most extinction-prone and most functionally efficient, contributing to rapid functional loss. Simulations confirmed that extinction order led to greater disruption of function than predicted by random species loss. Total abundance declined with richness and also appeared to contribute to loss of function. We demonstrate conceptually and empirically how the non-random response of communities to disturbance can have unexpectedly large functional consequences.

Data from: Can above-ground ecosystem services compensate for reduced fertilizer input and soil organic matter in annual crops?

NARCIS (Netherlands)

Gils, van S.H.; Putten, van der W.H.; Kleijn, D.

2016-01-01

Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure, and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop yield. We

Assessment of erecting nuclear power plants below ground in an open building pit

International Nuclear Information System (INIS)

Kroeger, W.; Altes, J.; Bongartz, R.; David, P.H.; Escherich, K.H.; Kasper, K.; Koschmieder, D.; Roethig, K.D.; Schwarzer, K.; Wolters, J.

1978-01-01

The technical feasibility, costs and safety potential of siting a nuclear power plant below ground level have been assessed. The reference plant was a 1,300 MWsub(e) PWR and the siting was based on a 'cut-and-cover' design in soil. The 'cut-and-cover' design enhances the safety potential of the site both with regard to extreme internal accidents and to external impacts inclusive of hostile attack. The measures required to 'harden' the site against these extreme conditions do not cancel each other. The realization of the safety potential is strongly dependent on the reliability of the closure equipment on routes to the atmosphere. These closures represent the remaining vulnerable feature of the design, as all other release paths are through soil which prevents any immediate danger to the public. The concepts considered include partial or complete lowering of the reactor. The thickness of the coverage depends on the degree of protection required and is typically between 8 and 13 m. The essential systems of the above-ground design are unchanged and therefore prior experience and existing designs can be applied. The concepts appear to be technically feasible including, in particular, the large pits and the additional closures; the technical difficulties, however, should not be underestimated. The depth of lowering does not determine the gain in safety because a well designed coverage can act as natural soil. Partial lowering, in fact, appears to be the more economic method. According to the degree of protection and the variations of design, the concepts would cost between 8 and 14% more than the capital cost of an equivalent above-ground plant. The construction time would be extended by 1.4 years for the concepts investigated. (orig./HP) [de

Similar below-ground carbon cycling dynamics but contrasting modes of nitrogen cycling between arbuscular mycorrhizal and ectomycorrhizal forests.

Science.gov (United States)

Lin, Guigang; McCormack, M Luke; Ma, Chengen; Guo, Dali

2017-02-01

Compared with ectomycorrhizal (ECM) forests, arbuscular mycorrhizal (AM) forests are hypothesized to have higher carbon (C) cycling rates and a more open nitrogen (N) cycle. To test this hypothesis, we synthesized 645 observations, including 22 variables related to below-ground C and N dynamics from 100 sites, where AM and ECM forests co-occurred at the same site. Leaf litter quality was lower in ECM than in AM trees, leading to greater forest floor C stocks in ECM forests. By contrast, AM forests had significantly higher mineral soil C concentrations, and this result was strongly mediated by plant traits and climate. No significant differences were found between AM and ECM forests in C fluxes and labile C concentrations. Furthermore, inorganic N concentrations, net N mineralization and nitrification rates were all higher in AM than in ECM forests, indicating 'mineral' N economy in AM but 'organic' N economy in ECM trees. AM and ECM forests show systematic differences in mineral vs organic N cycling, and thus mycorrhizal type may be useful in predicting how different tree species respond to multiple environmental change factors. By contrast, mycorrhizal type alone cannot reliably predict below-ground C dynamics without considering plant traits and climate. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Biodiversity as a solution to mitigate climate change impacts on the functioning of forest ecosystems.

Science.gov (United States)

Hisano, Masumi; Searle, Eric B; Chen, Han Y H

2018-02-01

Forest ecosystems are critical to mitigating greenhouse gas emissions through carbon sequestration. However, climate change has affected forest ecosystem functioning in both negative and positive ways, and has led to shifts in species/functional diversity and losses in plant species diversity which may impair the positive effects of diversity on ecosystem functioning. Biodiversity may mitigate climate change impacts on (I) biodiversity itself, as more-diverse systems could be more resilient to climate change impacts, and (II) ecosystem functioning through the positive relationship between diversity and ecosystem functioning. By surveying the literature, we examined how climate change has affected forest ecosystem functioning and plant diversity. Based on the biodiversity effects on ecosystem functioning (B→EF), we specifically address the potential for biodiversity to mitigate climate change impacts on forest ecosystem functioning. For this purpose, we formulate a concept whereby biodiversity may reduce the negative impacts or enhance the positive impacts of climate change on ecosystem functioning. Further B→EF studies on climate change in natural forests are encouraged to elucidate how biodiversity might influence ecosystem functioning. This may be achieved through the detailed scrutiny of large spatial/long temporal scale data sets, such as long-term forest inventories. Forest management strategies based on B→EF have strong potential for augmenting the effectiveness of the roles of forests in the mitigation of climate change impacts on ecosystem functioning. © 2017 Cambridge Philosophical Society.

Organism-Sediment Interactions Govern Post-Hypoxia Recovery of Ecosystem Functioning

Science.gov (United States)

Van Colen, Carl; Rossi, Francesca; Montserrat, Francesc; Andersson, Maria G. I.; Gribsholt, Britta; Herman, Peter M. J.; Degraer, Steven; Vincx, Magda; Ysebaert, Tom; Middelburg, Jack J.

2012-01-01

Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning. PMID:23185440

Above- and below-ground responses of Calamagrostis purpurea to UV-B radiation and elevated CO{sub 2} under phosphorus limitation

Energy Technology Data Exchange (ETDEWEB)

Bussell, J.S.; Gwynn-Jones, D.; Griffith, G.W.; Scullion, J. (Aberystwyth Univ., IBERS, Wales (United Kingdom))

2012-08-15

UV-B radiation and elevated CO{sub 2} may impact rhizosphere processes through altered below-ground plant resource allocation and root exudation, changes that may have implications for nutrient acquisition. As nutrients limit plant growth in many habitats, their supply may dictate plant response under elevated CO{sub 2}. This study investigated UV-B exposure and elevated CO{sub 2} effects, including interactions, on plant growth, tissue chemistry and rooting responses relating to P acquisition. The sub-arctic grass Calamagrostis purpurea was subjected to UV-B (0 or 3.04 kJ m-2day-1) and CO{sub 2} (ambient 380 or 650 ppmv) treatments in a factorial glasshouse experiment, with sparingly soluble P (0 or 0.152 mg P per plant as FePO{sub 4}) a further factor. It was hypothesized that UV-B exposure and elevated CO{sub 2} would change plant resource allocation, with CO{sub 2} mitigating adverse responses to UV-B exposure and aiding P uptake. Plant biomass and morphology, tissue composition and rhizosphere leachate properties were measured. UV-B directly affected chemical composition of shoots and interacted with CO{sub 2} to give a greater root biomass. Elevated CO{sub 2} altered the composition of both shoots and roots and increased shoot biomass and secondary root length, while leachate pH decreased. Below-ground responses to CO{sub 2} did not affect P acquisition although P limitation progressively reduced leachate pH and increased secondary root length. Although direct plant growth, foliar composition and below-ground nutrient acquisition responses were dominated by CO{sub 2} treatments, UV-B modified these CO{sub 2} responses significantly. These interactions have implications for plant responses to future atmospheric conditions. (Author)

Use of ground-based radiometers for L-Band Freeze/Thaw retrieval in a boreal forest site

Science.gov (United States)

Roy, A.; Sonnentag, O.; Derksen, C.; Toose, P.; Pappas, C.; Mavrovic, A.; El Amine, M.; Royer, A.; Berg, A. A.; Rowlandson, T. L.; Barr, A.; Black, T. A.

2017-12-01

The boreal forest is the second largest land biome in the world and thus plays a major role in the global and regional climate systems. The extent, timing and duration of the seasonal freeze/thaw (F/T) state influences vegetation developmental stages (phenology) and, consequently, constitutes an important control on how boreal forest ecosystems exchange carbon, water and energy with the atmosphere. Recently, new L-Band satellite-derived F/T information has become available. However, disentangling the seasonally differing contributions from forest overstory and understory vegetation, and the ground surface to the satellite signal remains challenging. Here we present results from an ongoing campaign with two L-Band surface-based radiometers (SBR) installed on a micrometeorological tower at the Southern Old Black Spruce site (53.99°N / 105.12°W) in central Saskatchewan. One radiometer unit is installed on top of the tower viewing the multi-layer vegetation canopy from above. A second radiometer unit is installed within the multi-layer canopy, viewing the understory and the ground surface only. The objectives of our study are to (i) disentangle the L-Band F/T signal contribution of boreal forest overstory from the combined understory and ground surface contribution, and (ii) link the L-Band F/T signal to related boreal forest structural and functional characteristics. Analysis of these radiometer measurements made from September to November 2016 shows that when the ground surface is thawed, the main contributor to both radiometer signals is soil moisture. The Pearson correlation coefficient between brightness temperature (TB) at vertical polarization (V-pol) and soil permittivity is 0.79 for the radiometer above the canopy and 0.74 for the radiometer below the canopy. Under cold conditions when the soil was thawed (snow insulation) and the trees were frozen (below 0°C), TB at V-pol is negatively correlated with tree permittivity. The freezing tree contribution to

Global meta-analysis of leaf area index in wetlands indicates uncertainties in understanding of their ecosystem function

Science.gov (United States)

Dronova, I.; Taddeo, S.; Foster, K.

2017-12-01

Projecting ecosystem responses to global change relies on the accurate understanding of properties governing their functions in different environments. An important variable in models of ecosystem function is canopy leaf area index (LAI; leaf area per unit ground area) declared as one of the Essential Climate Variables in the Global Climate Observing System and extensively measured in terrestrial landscapes. However, wetlands have been largely under-represented in these efforts, which globally limits understanding of their contribution to carbon sequestration, climate regulation and resilience to natural and anthropogenic disturbances. This study provides a global synthesis of >350 wetland-specific LAI observations from 182 studies and compares LAI among wetland ecosystem and vegetation types, biomes and measurement approaches. Results indicate that most wetland types and even individual locations show a substantial local dispersion of LAI values (average coefficient of variation 65%) due to heterogeneity of environmental properties and vegetation composition. Such variation indicates that mean LAI values may not sufficiently represent complex wetland environments, and the use of this index in ecosystem function models needs to incorporate within-site variation in canopy properties. Mean LAI did not significantly differ between direct and indirect measurement methods on a pooled global sample; however, within some of the specific biomes and wetland types significant contrasts between these approaches were detected. These contrasts highlight unique aspects of wetland vegetation physiology and canopy structure affecting measurement principles that need to be considered in generalizing canopy properties in ecosystem models. Finally, efforts to assess wetland LAI using remote sensing strongly indicate the promise of this technology for cost-effective regional-scale modeling of canopy properties similar to terrestrial systems. However, such efforts urgently require more

Alternative states of a semiarid grassland ecosystem: implications for ecosystem services

Science.gov (United States)

Miller, Mark E.; Belote, R. Travis; Bowker, Matthew A.; Garman, Steven L.

2011-01-01

Ecosystems can shift between alternative states characterized by persistent differences in structure, function, and capacity to provide ecosystem services valued by society. We examined empirical evidence for alternative states in a semiarid grassland ecosystem where topographic complexity and contrasting management regimes have led to spatial variations in levels of livestock grazing. Using an inventory data set, we found that plots (n = 72) cluster into three groups corresponding to generalized alternative states identified in an a priori conceptual model. One cluster (biocrust) is notable for high coverage of a biological soil crust functional group in addition to vascular plants. Another (grass-bare) lacks biological crust but retains perennial grasses at levels similar to the biocrust cluster. A third (annualized-bare) is dominated by invasive annual plants. Occurrence of grass-bare and annualized-bare conditions in areas where livestock have been excluded for over 30 years demonstrates the persistence of these states. Significant differences among all three clusters were found for percent bare ground, percent total live cover, and functional group richness. Using data for vegetation structure and soil erodibility, we also found large among-cluster differences in average levels of dust emissions predicted by a wind-erosion model. Predicted emissions were highest for the annualized-bare cluster and lowest for the biocrust cluster, which was characterized by zero or minimal emissions even under conditions of extreme wind. Results illustrate potential trade-offs among ecosystem services including livestock production, soil retention, carbon storage, and biodiversity conservation. Improved understanding of these trade-offs may assist ecosystem managers when evaluating alternative management strategies.

Marine biodiversity-ecosystem functions under uncertain environmental futures.

Science.gov (United States)

Bulling, Mark T; Hicks, Natalie; Murray, Leigh; Paterson, David M; Raffaelli, Dave; White, Piran C L; Solan, Martin

2010-07-12

Anthropogenic activity is currently leading to dramatic transformations of ecosystems and losses of biodiversity. The recognition that these ecosystems provide services that are essential for human well-being has led to a major interest in the forms of the biodiversity-ecosystem functioning relationship. However, there is a lack of studies examining the impact of climate change on these relationships and it remains unclear how multiple climatic drivers may affect levels of ecosystem functioning. Here, we examine the roles of two important climate change variables, temperature and concentration of atmospheric carbon dioxide, on the relationship between invertebrate species richness and nutrient release in a model benthic estuarine system. We found a positive relationship between invertebrate species richness and the levels of release of NH(4)-N into the water column, but no effect of species richness on the release of PO(4)-P. Higher temperatures and greater concentrations of atmospheric carbon dioxide had a negative impact on nutrient release. Importantly, we found significant interactions between the climate variables, indicating that reliably predicting the effects of future climate change will not be straightforward as multiple drivers are unlikely to have purely additive effects, resulting in increased levels of uncertainty.

Marine biodiversity–ecosystem functions under uncertain environmental futures

Science.gov (United States)

Bulling, Mark T.; Hicks, Natalie; Murray, Leigh; Paterson, David M.; Raffaelli, Dave; White, Piran C. L.; Solan, Martin

2010-01-01

Anthropogenic activity is currently leading to dramatic transformations of ecosystems and losses of biodiversity. The recognition that these ecosystems provide services that are essential for human well-being has led to a major interest in the forms of the biodiversity–ecosystem functioning relationship. However, there is a lack of studies examining the impact of climate change on these relationships and it remains unclear how multiple climatic drivers may affect levels of ecosystem functioning. Here, we examine the roles of two important climate change variables, temperature and concentration of atmospheric carbon dioxide, on the relationship between invertebrate species richness and nutrient release in a model benthic estuarine system. We found a positive relationship between invertebrate species richness and the levels of release of NH4-N into the water column, but no effect of species richness on the release of PO4-P. Higher temperatures and greater concentrations of atmospheric carbon dioxide had a negative impact on nutrient release. Importantly, we found significant interactions between the climate variables, indicating that reliably predicting the effects of future climate change will not be straightforward as multiple drivers are unlikely to have purely additive effects, resulting in increased levels of uncertainty. PMID:20513718

Consequences of increasing hypoxic disturbance on benthic communities and ecosystem functioning.

Directory of Open Access Journals (Sweden)

Anna Villnäs

Full Text Available Disturbance-mediated species loss has prompted research considering how ecosystem functions are changed when biota is impaired. However, there is still limited empirical evidence from natural environments evaluating the direct and indirect (i.e. via biota effects of disturbance on ecosystem functioning. Oxygen deficiency is a widespread threat to coastal and estuarine communities. While the negative impacts of hypoxia on benthic communities are well known, few studies have assessed in situ how benthic communities subjected to different degrees of hypoxic stress alter their contribution to ecosystem functioning. We studied changes in sediment ecosystem function (i.e. oxygen and nutrient fluxes across the sediment water-interface by artificially inducing hypoxia of different durations (0, 3, 7 and 48 days in a subtidal sandy habitat. Benthic chamber incubations were used for measuring responses in sediment oxygen and nutrient fluxes. Changes in benthic species richness, structure and traits were quantified, while stress-induced behavioral changes were documented by observing bivalve reburial rates. The initial change in faunal behavior was followed by non-linear degradation in benthic parameters (abundance, biomass, bioturbation potential, gradually impairing the structural and functional composition of the benthic community. In terms of ecosystem function, the increasing duration of hypoxia altered sediment oxygen consumption and enhanced sediment effluxes of NH(4(+ and dissolved Si. Although effluxes of PO(4(3- were not altered significantly, changes were observed in sediment PO(4(3- sorption capability. The duration of hypoxia (i.e. number of days of stress explained a minor part of the changes in ecosystem function. Instead, the benthic community and disturbance-driven changes within the benthos explained a larger proportion of the variability in sediment oxygen- and nutrient fluxes. Our results emphasize that the level of stress to the

Ground Monitoring Neotropical Dry Forests: A Sensor Network for Forest and Microclimate Dynamics in Semi-Arid Environments (Enviro-Net°)

Science.gov (United States)

Rankine, C. J.; Sánchez-Azofeifa, G.

2011-12-01

In the face of unprecedented global change driven by anthropogenic pressure on natural systems it has become imperative to monitor and better understand potential shifts in ecosystem functioning and services from local to global scales. The utilization of automated sensors technologies offers numerous advantages over traditional on-site ecosystem surveying techniques and, as a result, sensor networks are becoming a powerful tool in environmental monitoring programs. Tropical forests, renowned for their biodiversity, are important regulators of land-atmosphere fluxes yet the seasonally dry tropical forests, which account for 40% of forested ecosystems in the American tropics, have been severely degraded over the past several decades and not much is known of their capacity to recover. With less than 1% of these forests protected, our ability to monitor the dynamics and quantify changes in the remaining primary and recovering secondary tropical dry forests is vital to understanding mechanisms of ecosystem stress responses and climate feedback with respect to annual productivity and desertification processes in the tropics. The remote sensing component of the Tropi-Dry: Human and Biophysical Dimensions of Tropical Dry Forests in the Americas research network supports a network of long-term tropical ecosystem monitoring platforms which focus on the dynamics of seasonally dry tropical forests in the Americas. With over 25 sensor station deployments operating across a latitudinal gradient in Mexico, Costa Rica, Brazil, and Argentina continuously collecting hyper-temporal sensory input based on standardized deployment parameters, this monitoring system is unique among tropical environments. Technologies used in the network include optical canopy phenology towers, understory wireless sensing networks, above and below ground microclimate stations, and digital cameras. Sensory data streams are uploaded to a cyber-infrastructure initiative, denominated Enviro-Net°, for data

The Catena Concept Revisited: Spatial Optimization of Ecohydrologic Form and Function

Science.gov (United States)

Band, L. E.; Hwang, T.

2009-05-01

Over the past two decades, empirical evidence and theory have been developed that suggest that plot scale ecosystem properties such as canopy density and root depth evolve towards a state that maximizes resource use and net primary productivity. We generalize this concept from the plot scale to the catchment by examining canopy density as a function of available energy, water and nutrients connected along hydrologic flowpaths. We use a combination of field measurement, signal processing and distributed simulation to identify emergent optimal ecohydrologic patterns in a set of Long Term Ecological Research sites reflecting the interactions between catchment geomorphic, soil, climate and ecosystem processes. Results to date reveal interesting adjustments of above and below ground canopy structure and physiologic function with water and nutrient availability that indicate the tendency to develop landscape scale optimization, beyond that achieved at individual plots, of net primary productivity and water use efficiency.

Ecosystem Functions Connecting Contributions from Ecosystem Services to Human Wellbeing in a Mangrove System in Northern Taiwan.

Science.gov (United States)

Hsieh, Hwey-Lian; Lin, Hsing-Juh; Shih, Shang-Shu; Chen, Chang-Po

2015-06-09

The present study examined a mangrove ecosystem in northern Taiwan to determine how the various components of ecosystem function, ecosystem services and human wellbeing are connected. The overall contributions of mangrove services to specific components of human wellbeing were also assessed. A network was developed and evaluated by an expert panel consisting of hydrologists, ecologists, and experts in the field of culture, landscape or architecture. The results showed that supporting habitats was the most important function to human wellbeing, while water quality, habitable climate, air quality, recreational opportunities, and knowledge systems were services that were strongly linked to human welfare. Security of continuous supply of services appeared to be the key to a comfortable life. From a bottom-up and top-down perspective, knowledge systems (a service) were most supported by ecosystem functions, while the security of continuous supply of services (wellbeing) had affected the most services. In addition, the overall benefits of mangrove services to human prosperity concentrated on mental health, security of continuous supply of services, and physical health.

Ecosystem Functions Connecting Contributions from Ecosystem Services to Human Wellbeing in a Mangrove System in Northern Taiwan

Directory of Open Access Journals (Sweden)

Hwey-Lian Hsieh

2015-06-01

Full Text Available The present study examined a mangrove ecosystem in northern Taiwan to determine how the various components of ecosystem function, ecosystem services and human wellbeing are connected. The overall contributions of mangrove services to specific components of human wellbeing were also assessed. A network was developed and evaluated by an expert panel consisting of hydrologists, ecologists, and experts in the field of culture, landscape or architecture. The results showed that supporting habitats was the most important function to human wellbeing, while water quality, habitable climate, air quality, recreational opportunities, and knowledge systems were services that were strongly linked to human welfare. Security of continuous supply of services appeared to be the key to a comfortable life. From a bottom-up and top-down perspective, knowledge systems (a service were most supported by ecosystem functions, while the security of continuous supply of services (wellbeing had affected the most services. In addition, the overall benefits of mangrove services to human prosperity concentrated on mental health, security of continuous supply of services, and physical health.

Ecosystem function and biodiversity on coral reefs

OpenAIRE

Ogden, J.; Done, T.; Salvat, B.

1994-01-01

The article highlights a workshop held in Key West, Florida in November 1993 attended by a group of 35 international scientists where topics of ecosystem function and biodiversity on coral reefs were discussed.

The Unilateral Below Elbow Test: a function test for children with unilateral congenital below elbow deficiency.

Science.gov (United States)

Bagley, Anita M; Molitor, Fred; Wagner, Lisa V; Tomhave, Wendy; James, Michelle A

2006-07-01

The Unilateral Below Elbow Test (UBET) was developed to evaluate function in bimanual activities for both the prosthesis wearer and non-wearer. Nine tasks were chosen for each of four age-specific categories defined by development stages of hand function (2-4y, 5-7y, 8-10y, and 11-21y). Two scales, Completion of Task and Method of Use, were designed to rate performance. To measure reliability, four occupational therapists scored samples of videotaped UBET performances. For Completion of Task, an interval scale, agreement in scoring was measured with interclass correlation coefficients (ICC; n=9; five females, four males). For Method of Use, a nominal scale, chance-adjusted association was calculated with Cohen's kappa coefficients (interobserver n=198; 111 females, 87 males; intraobserver n=93; 56 females, 37 males). For Completion of Task, the average ICC was 0.87 for the prosthesis-on condition, and 0.85 for the prosthesis-off condition. ICCs exceeded 0.80 for eight out of nine tasks for the two older age groups, but for only five out of nine tasks in the younger age groups. Higher inter- and intraobserver kappa coefficients for Method of Use resulted when scoring children with their prostheses on versus off. The oldest age group had lower kappa values than the other three groups. The UBET is recommended for the functional evaluation of Completion of Task in children with unilateral congenital below elbow deficiency with and without their prostheses. Method of Use scoring can evaluate individuals for directed therapy interventions or prosthetic training.

Realizing ecosystem services: wetland hydrologic function along a gradient of ecosystem condition.

Science.gov (United States)

McLaughlin, Daniel L; Cohen, Matthew J

2013-10-01

Wetlands provide numerous ecosystem services, from habitat provision to pollutant removal, floodwater storage, and microclimate regulation. Delivery of particular services relies on specific ecological functions, and thus to varying degree on wetland ecological condition, commonly quantified as departure from minimally impacted reference sites. Condition assessments are widely adopted as regulatory indicators of ecosystem function, and for some services (e.g., habitat) links between condition and function are often direct. For others, however, links are more tenuous, and using condition alone to enumerate ecosystem value (e.g., for compensatory mitigation) may underestimate important services. Hydrologic function affects many services cited in support of wetland protection both directly (floodwater retention, microclimate regulation) and indirectly (biogeochemical cycling, pollutant removal). We investigated links between condition and hydrologic function to test the hypothesis, embedded in regulatory assessment of wetland value, that condition predicts function. Condition was assessed using rapid and intensive approaches, including Florida's official wetland assessment tool, in 11 isolated forested wetlands in north Florida (USA) spanning a land use intensity gradient. Hydrologic function was assessed using hydrologic regime (mean, variance, and rates of change of water depth), and measurements of groundwater exchange and evapotranspiration (ET). Despite a wide range in condition, no systematic variation in hydrologic regime was observed; indeed reference sites spanned the full range of variation. In contrast, ET was affected by land use, with higher rates in intensive (agriculture and urban) landscapes in response to higher leaf area. ET determines latent heat exchange, which regulates microclimate, a valuable service in urban heat islands. Higher ET also indicates higher productivity and thus carbon cycling. Groundwater exchange regularly reversed flow direction

Mapping ecosystem functions and services in Eastern Europe using global-scale data sets

NARCIS (Netherlands)

Schulp, C.J.E.; Alkemade, R.; Klein Goldewijk, K.; Petz, K.

2012-01-01

To assess future interactions between the environment and human well-being, spatially explicit ecosystem service models are needed. Currently available models mainly focus on provisioning services and do not distinguish changes in the functioning of the ecosystem (Ecosystem Functions – ESFs) and

Production dynamics of fine roots in beech forests: possible mechanism of resource allocation between above- and below-ground production

Science.gov (United States)

Nakahata, R.; Osawa, A.; Naramoto, M.; Mizunaga, H.; Sato, M.

2017-12-01

The masting phenomenon that seed production has large annual variation with spatial synchrony appears generally in beeches. Therefore, net primary production and carbon allocation mechanism in beech forests may differ among several years in relation to annual variation of seed production. On the other hand, fine roots play key roles in carbon dynamics and nutrient and water acquisition of an ecosystem. Evaluation of fine root dynamics is essential to understand long-term dynamics of production in forest ecosystems. Moreover, the influence of mast seeding on resource allocation should be clarified in such beech forests. The aim of this study is to clarify possible relationships between the patterns of above- and below-ground production in relation to the masting events using observation data of litter fall and fine root dynamics. We applied the litter trap method and a minirhizotron method in a cool-temperate natural forest dominated by beech (Fagus crenata Blume). Ten litter traps were set from 2008 to 2016, then annual leaf and seed production were estimated. Four minirhizotron tubes were buried in Aug. 2008 and soil profiles were scanned monthly until Nov. 2016 during the periods of no snow covering. The scanned soil profiles were analyzed for calculating fine root production using the WinRHIZO Tron software. In the present study site, rich production of mast seeding occurred biennially and fine root production showed various seasonal patterns. There was no significant correlation between seed production and annual fine root production in the same year. However, seed production had a positive correlation with fine root production in autumn in the previous year and indicated a negative correlation with that in autumn in the current year. These results indicate that higher fine root production has led to increased nutrient acquisition, which resulted in rich seed production in the next year. It is also suppressed after the masting events due to shortage in

Ecosystem engineering by invasive exotic beavers reduces in-stream diversity and enhances ecosystem function in Cape Horn, Chile.

Science.gov (United States)

Anderson, Christopher B; Rosemond, Amy D

2007-11-01

Species invasions are of global significance, but predicting their impacts can be difficult. Introduced ecosystem engineers, however, provide an opportunity to test the underlying mechanisms that may be common to all invasive engineers and link relationships between changes in diversity and ecosystem function, thereby providing explanatory power for observed ecological patterns. Here we test specific predictions for an invasive ecosystem engineer by quantifying the impacts of habitat and resource modifications caused by North American beavers (Castor canadensis) on aquatic macroinvertebrate community structure and stream ecosystem function in the Cape Horn Biosphere Reserve, Chile. We compared responses to beavers in three habitat types: (1) forested (unimpacted) stream reaches, (2) beaver ponds, and (3) sites immediately downstream of beaver dams in four streams. We found that beaver engineering in ponds created taxonomically simplified, but more productive, benthic macroinvertebrate assemblages. Specifically, macroinvertebrate richness, diversity and number of functional feeding groups were reduced by half, while abundance, biomass and secondary production increased three- to fivefold in beaver ponds compared to forested sites. Reaches downstream of beaver ponds were very similar to natural forested sections. Beaver invasion effects on both community and ecosystem parameters occurred predominantly via increased retention of fine particulate organic matter, which was associated with reduced macroinvertebrate richness and diversity (via homogenization of benthic microhabitat) and increased macroinvertebrate biomass and production (via greater food availability). Beaver modifications to macroinvertebrate community structure were largely confined to ponds, but increased benthic production in beaver-modified habitats adds to energy retention and flow for the entire stream ecosystem. Furthermore, the effects of beavers on taxa richness (negative) and measures of

Function of Wildfire-Deposited Pyrogenic Carbon in Terrestrial Ecosystems

Directory of Open Access Journals (Sweden)

Melissa R. A. Pingree

2017-08-01

Full Text Available Fire is an important driver of change in most forest, savannah, and prairie ecosystems and fire-altered organic matter, or pyrogenic carbon (PyC, conveys numerous functions in soils of fire-maintained terrestrial ecosystems. Although an exceptional number of recent review articles and books have addressed agricultural soil application of charcoal or biochar, few reviews have addressed the functional role of naturally formed PyC in fire-maintained ecosystems. Recent advances in molecular spectroscopic techniques have helped strengthen our understanding of PyC as a ubiquitous, complex material that is capable of altering soil chemical, physical, and biological properties and processes. The uniquely recalcitrant nature of PyC in soils is partly a result of its stable C = C double-bonded, graphene-like structure and C-rich, N-poor composition. This attribute allows it to persist in soils for hundreds to thousands of years and represent net ecosystem C sequestration in fire-maintained ecosystems. The rapid formation of PyC during wildfire or anthropogenic fire events short-circuits the normally tortuous pathway of recalcitrant soil C formation. Existing literature also suggests that PyC provides an essential role in the cycling of certain nutrients, greatly extending the timeframe by which fires influence soil processes and facilitating recovery in ecosystems where organic matter inputs are low and post-fire surface soil bacterial and fungal activity is reduced. The high surface area of PyC allows for the adsorption a broad spectrum of organic compounds that directly or indirectly influence microbial processes after fire events. Adsorption capacity and microsite conditions created by PyC yields a “charosphere” effect in soil with heightened microbial activity in the vicinity of PyC. In this mini-review, we explore the function of PyC in natural and semi-natural settings, provide a mechanistic approach to understanding these functions, and examine

Ecosystem Functions Connecting Contributions from Ecosystem Services to Human Wellbeing in a Mangrove System in Northern Taiwan

OpenAIRE

Hsieh, Hwey-Lian; Lin, Hsing-Juh; Shih, Shang-Shu; Chen, Chang-Po

2015-01-01

The present study examined a mangrove ecosystem in northern Taiwan to determine how the various components of ecosystem function, ecosystem services and human wellbeing are connected. The overall contributions of mangrove services to specific components of human wellbeing were also assessed. A network was developed and evaluated by an expert panel consisting of hydrologists, ecologists, and experts in the field of culture, landscape or architecture. The results showed that supporting habitats...

Continental-scale effects of nutrient pollution on stream ecosystem functioning.

Science.gov (United States)

Woodward, Guy; Gessner, Mark O; Giller, Paul S; Gulis, Vladislav; Hladyz, Sally; Lecerf, Antoine; Malmqvist, Björn; McKie, Brendan G; Tiegs, Scott D; Cariss, Helen; Dobson, Mike; Elosegi, Arturo; Ferreira, Verónica; Graça, Manuel A S; Fleituch, Tadeusz; Lacoursière, Jean O; Nistorescu, Marius; Pozo, Jesús; Risnoveanu, Geta; Schindler, Markus; Vadineanu, Angheluta; Vought, Lena B-M; Chauvet, Eric

2012-06-15

Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

An experimental framework to identify community functional components driving ecosystem processes and services delivery

Czech Academy of Sciences Publication Activity Database

Dias, A. T. C.; Berg, M. P.; de Bello, Francesco; Oosten, A. R. V.; Bílá, Karolína; Morreti, M.

2013-01-01

Roč. 101, č. 1 (2013), s. 29-37 ISSN 0022-0477 R&D Projects: GA ČR GAP505/12/1296 Institutional support: RVO:67985939 ; RVO:67179843 Keywords : CWM * ecosystem functioning * ecosystem processes * ecosystem services * functional divergence * functional diversity * functional evenness * functional richness * mass ratio hypothesis * Rao index Subject RIV: EH - Ecology, Behaviour; EF - Botanics (BU-J) Impact factor: 5.694, year: 2013

Leaf and fine root carbon stocks and turnover are coupled across Arctic ecosystems.

Science.gov (United States)

Sloan, Victoria L; Fletcher, Benjamin J; Press, Malcolm C; Williams, Mathew; Phoenix, Gareth K

2013-12-01

Estimates of vegetation carbon pools and their turnover rates are central to understanding and modelling ecosystem responses to climate change and their feedbacks to climate. In the Arctic, a region containing globally important stores of soil carbon, and where the most rapid climate change is expected over the coming century, plant communities have on average sixfold more biomass below ground than above ground, but knowledge of the root carbon pool sizes and turnover rates is limited. Here, we show that across eight plant communities, there is a significant positive relationship between leaf and fine root turnover rates (r(2) = 0.68, P turnover rates of both leaf (r(2) = 0.63, P community scale. These ecological relationships not only demonstrate close links between above and below-ground plant carbon dynamics but also allow plant carbon pool sizes and their turnover rates to be predicted from the single readily quantifiable (and remotely sensed) parameter of LAI, including the possibility of estimating root data from satellites. © 2013 John Wiley & Sons Ltd.

Ecosystem Function: Cyanobacteria Solutions, A Missed Opportunity?

Science.gov (United States)

Stream and wetland riparian functions integrate the relationships between species, their habitats and fostering ecosystem resilience, which is critical to resilience – i.e., ensuring long-term sustainability. These relationships are dependent on the drivers of ecological functio...

Above- and below-ground effects of plant diversity depend on species origin

DEFF Research Database (Denmark)

Kuebbing, Sara E.; Classen, Aimee Taylor; Sanders, Nate

2015-01-01

-interaction models to describe how species' interactions influenced diversity-productivity relationships. Communities with more species had higher total biomass than did monoculture communities, but native and nonnative communities diverged in root : shoot ratios and the mechanism responsible for increased......Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired...... native and nonnative plant communities in a glasshouse experiment to test diversity-productivity relationships and responsible mechanisms (i.e. selection or complementarity effects). Additionally, we tested how productivity and associated mechanisms influenced seedling establishment. We used diversity...

Contrasting land uses in Mediterranean agro-silvo-pastoral systems generated patchy diversity patterns of vascular plants and below-ground microorganisms.

Science.gov (United States)

Bagella, Simonetta; Filigheddu, Rossella; Caria, Maria Carmela; Girlanda, Mariangela; Roggero, Pier Paolo

2014-12-01

The aims of this paper were (i) to define how contrasting land uses affected plant biodiversity in Mediterranean agro-silvo-pastoral-systems across a gradient of disturbance regimes: cork oak forests, secondary grasslands, hay crops, grass covered vineyards, tilled vineyards; (ii) to determine whether these patterns mirrored those of below-ground microorganisms and whether the components of γ-diversity followed a similar model. The disturbance regimes affected plant assemblage composition. Species richness decreased with increasing land use intensity, the Shannon index showed the highest values in grasslands and hay crops. Plant assemblage composition patterns mirrored those of Basidiomycota and Ascomycota. Richness in Basidiomycota, denitrifying bacteria and microbial biomass showed the same trend as that observed for vascular plant richness. The Shannon index pattern of below-ground microorganisms was different from that of plants. The plant γ-diversity component model weakly mirrored those of Ascomycota. Patchy diversity patterns suggest that the maintenance of contrasting land uses associated with different productions typical of agro-silvo-pastoral-systems can guarantee the conservation of biodiversity. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

[Assessment on the changing conditions of ecosystems in key ecological function zones in China].

Science.gov (United States)

Huang, Lin; Cao, Wei; Wu, Dan; Gong, Guo-li; Zhao, Guo-song

2015-09-01

In this paper, the dynamics of ecosystem macrostructure, qualities and core services during 2000 and 2010 were analyzed for the key ecological function zones of China, which were classified into four types of water conservation, soil conservation, wind prevention and sand fixation, and biodiversity maintenance. In the water conservation ecological function zones, the areas of forest and grassland ecosystems were decreased whereas water bodies and wetland were increased in the past 11 years, and the water conservation volume of forest, grassland and wetland ecosystems increased by 2.9%. This region needs to reverse the decreasing trends of forest and grassland ecosystems. In the soil conservation ecological function zones, the area of farmland ecosystem was decreased, and the areas of forest, grassland, water bodies and wetland ecosystems were increased. The total amount of the soil erosion was reduced by 28.2%, however, the soil conservation amount of ecosystems increased by 38.1%. In the wind prevention and sand fixation ecological function zones, the areas of grassland, water bodies and wetland ecosystems were decreased, but forest and farmland ecosystems were increased. The unit amount of the soil. wind erosion was reduced and the sand fixation amount of ecosystems increased lightly. In this kind of region that is located in arid and semiarid areas, ecological conservation needs to reduce farmland area and give priority to the protection of the original ecological system. In the biodiversity maintenance ecological function zones, the areas of grassland and desert ecosystems were decreased and other types were increased. The human disturbances showed a weakly upward trend and needs to be reduced. The key ecological function zones should be aimed at the core services and the protecting objects, to assess quantitatively on the effectiveness of ecosystem conservation and improvement.

Continental-Scale Effects of Nutrient Pollution on Stream Ecosystem Functioning

OpenAIRE

Woodward , Guy; Gessner , Mark O.; Giller , Paul S.; Gulis , Vladislav; Hladyz , Sally; Lecerf , Antoine; Malmqvist , Björn; McKie , Brendan G.; Tiegs , Scott D.; Cariss , Helen; Dobson , Mike; Elosegi , Arturo; Ferreira , Veronica; Graça , Manuel A. S.; Fleituch , Tadeusz

2012-01-01

International audience; Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 100...

Dosimetry of Rn-222 in the air in environments located above and below ground level

International Nuclear Information System (INIS)

Cazula, Camila Dias

2015-01-01

Exposure of the general population to ionizing radiation comes mainly from natural sources. The main contribution is due to inhalation of radon (Rn-222), a gas that occurs naturally (UNSCEAR, 2000). The Rn-222 concentration in the environment is controlled by factors such as soil permeability and water content, the weather variability, materials used in the foundation and the usual positive pressure differential between the soil and the internal environment. Studies indicate that the concentration of radon shows a wide variation in the basement, ground floor and upper floors of buildings. The objective of this study is to determine radon levels in basements, ground floor and floors above ground level, at a university in the city of Sao Paulo and in one residential building in the city of Peruibe. Rn-222 measurements were performed using the method with nuclear track of solid state detectors (CR-39). The studied environments present Rn-222 concentration well below the values recommended by the International Commission on Radiological Protection, published in the 2009 document, of 300 Bq/m 3 for homes and 1000 Bq/m 3 for the workplace. In the residential building, the concentration of Ra-266, Th-232 and K-40 in the materials used in the building construction was also analyzed, by gamma spectrometry. The effective total dose for the resident due to external exposure was 0.8 mSv y -1 , lower than the annual dose limit for the general public of 1 mSv y -1 . (author)

Towards an integration of biodiversity-ecosystem functioning and food web theory to evaluate relationships between multiple ecosystem services

NARCIS (Netherlands)

Hines, Jes; van der Putten, W.H.; De Deyn, G.B.; Wagg, Cameron; Voigt, Winfried; Mulder, Christian; Weisser, Wolfgang W.; Engel, Jan; Melian, Carlos; Scheu, Stefan; Birkhofer, Klaus; Ebeling, Anne; Scherber, Christoph; Eisenhauer, Nico

2015-01-01

Ecosystem responses to changes in species diversity are often studied individually. However, changes in species diversity can simultaneously influence multiple interdependent ecosystem functions. Therefore, an important challenge is to determine when and how changes in species diversity that

Consequences of tropical land use for multitrophic biodiversity and ecosystem functioning.

Science.gov (United States)

Barnes, Andrew D; Jochum, Malte; Mumme, Steffen; Haneda, Noor Farikhah; Farajallah, Achmad; Widarto, Tri Heru; Brose, Ulrich

2014-10-28

Our knowledge about land-use impacts on biodiversity and ecosystem functioning is mostly limited to single trophic levels, leaving us uncertain about whole-community biodiversity-ecosystem functioning relationships. We analyse consequences of the globally important land-use transformation from tropical forests to oil palm plantations. Species diversity, density and biomass of invertebrate communities suffer at least 45% decreases from rainforest to oil palm. Combining metabolic and food-web theory, we calculate annual energy fluxes to model impacts of land-use intensification on multitrophic ecosystem functioning. We demonstrate a 51% reduction in energy fluxes from forest to oil palm communities. Species loss clearly explains variation in energy fluxes; however, this relationship depends on land-use systems and functional feeding guilds, whereby predators are the most heavily affected. Biodiversity decline from forest to oil palm is thus accompanied by even stronger reductions in functionality, threatening to severely limit the functional resilience of communities to cope with future global changes.

Seal carrion is a predictable resource for coastal ecosystems

Science.gov (United States)

Quaggiotto, Maria-Martina; Barton, Philip S.; Morris, Christopher D.; Moss, Simon E. W.; Pomeroy, Patrick P.; McCafferty, Dominic J.; Bailey, David M.

2018-04-01

The timing, magnitude, and spatial distribution of resource inputs can have large effects on dependent organisms. Few studies have examined the predictability of such resources and no standard ecological measure of predictability exists. We examined the potential predictability of carrion resources provided by one of the UK's largest grey seal (Halichoerus grypus) colonies, on the Isle of May, Scotland. We used aerial (11 years) and ground surveys (3 years) to quantify the variability in time, space, quantity (kg), and quality (MJ) of seal carrion during the seal pupping season. We then compared the potential predictability of seal carrion to other periodic changes in food availability in nature. An average of 6893 kg of carrion •yr-1 corresponding to 110.5 × 103 MJ yr-1 was released for potential scavengers as placentae and dead animals. A fifth of the total biomass from dead seals was consumed by the end of the pupping season, mostly by avian scavengers. The spatial distribution of carcasses was similar across years, and 28% of the area containing >10 carcasses ha-1 was shared among all years. Relative standard errors (RSE) in space, time, quantity, and quality of carrion were all below 34%. This is similar to other allochthonous-dependent ecosystems, such as those affected by migratory salmon, and indicates high predictability of seal carrion as a resource. Our study illustrates how to quantify predictability in carrion, which is of general relevance to ecosystems that are dependent on this resource. We also highlight the importance of carrion to marine coastal ecosystems, where it sustains avian scavengers thus affecting ecosystem structure and function.

Nitrogen Dynamics in European Forest Ecosystems: Considerations regarding Anthropogenic Nitrogen Depositions

OpenAIRE

Agren, G.I.; Kauppi, P.

1983-01-01

This study deals with the nutrient cycle of forest ecosystems over large geographic regions in Europe as affected by nitrogen deposition. The view is taken that the nitrogen cycle of a forest ecosystem has a maximum capacity for circulating nitrogen. Two different cases are defined: case (1) in which the nutrient cycle functions below its maximum capacity, and case (2) in which the circulation operates at the maximum level.

Effects of biodiversity on ecosystem functioning: a consensus of current knowledge

Science.gov (United States)

Hooper, D.U.; Chapin, F. S.; Ewel, J.J.; Hector, A.; Inchausti, P.; Lavorel, S.; Lawton, J.H.; Lodge, D.M.; Loreau, M.; Naeem, S.; Schmid, B.; SetSlS, H.; Symstad, A.J.; Vandermeer, J.; Wardle, D.A.

2005-01-01

Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth's biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services they provide to humanity. Ecological experiments, observations, and theoretical developments show that ecosystem properties depend greatly on biodiversity in terms of the functional characteristics of organisms present in the ecosystem and the distribution and abundance of those organisms over space and time. Species effects act in concert with the effects of climate, resource availability, and disturbance regimes in influencing ecosystem properties. Human activities can modify all of the above factors; here we focus on modification of these biotic controls.The scientific community has come to a broad consensus on many aspects of the relationship between biodiversity and ecosystem functioning, including many points relevant to management of ecosystems. Further progress will require integration of knowledge about biotic and abiotic controls on ecosystem properties, how ecological communities are structured, and the forces driving species extinctions and invasions. To strengthen links to policy and management, we also need to integrate our ecological knowledge with understanding of the social and economic constraints of potential management practices. Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth's ecosystems and the diverse biota they contain.Based on our review of the scientific literature, we are certain of the following conclusions:1) Species' functional characteristics strongly influence ecosystem properties. Functional characteristics operate in a variety of contexts

Riparian ecosystems and buffers - multiscale structure, function, and management: introduction

Science.gov (United States)

Kathleen A. Dwire; Richard R. Lowrance

2006-01-01

Given the importance of issues related to improved understanding and management of riparian ecosystems and buffers, the American Water Resources Association (AWRA) sponsored a Summer Specialty Conference in June 2004 at Olympic Valley, California, entitled 'Riparian Ecosystems and Buffers: Multiscale Structure, Function, and Management.' The primary objective...

A rapid method for landscape assessment of carbon storage and ecosystem function in moss and lichen ground layers

Science.gov (United States)

Sarah Jovan; Robert J. Smith; Juan C. Benavides; Michael Amacher; Bruce McCune

2015-01-01

Mat-forming ‘‘ground layers’’ of mosses and lichens often have functional impacts disproportionate to their biomass, and are responsible for sequestering one-third of the world’s terrestrial carbon as they regulate water tables, cool soils and inhibit microbial decomposition. Without reliable assessment tools, the potential effects of climate and land use changes on...

Long-term development of above- and below-ground carbon stocks following land-use change in subalpine ecosystems of the Swiss National Park

Science.gov (United States)

Anita C. Risch; Martin F. Jurgensen; Deborah S. Page-Dumroese; Otto Wildi; Martin Schultz

2008-01-01

Vegetation changes following agricultural land abandonment at high elevation - which is frequent in Europe - could have a major impact on carbon (C) sequestration. However, most information on the effects of vegetation changes on ecosystem C stocks originates from low-elevation studies on reforestation or early successional forests, and little is known about how these...

Ecosystem classification, Chapter 2

Science.gov (United States)

M.J. Robin-Abbott; L.H. Pardo

2011-01-01

The ecosystem classification in this report is based on the ecoregions developed through the Commission for Environmental Cooperation (CEC) for North America (CEC 1997). Only ecosystems that occur in the United States are included. CEC ecoregions are described, with slight modifications, below (CEC 1997) and shown in Figures 2.1 and 2.2. We chose this ecosystem...

Bird functional diversity decreases with time since disturbance: Does patchy prescribed fire enhance ecosystem function?.

Science.gov (United States)

Sitters, Holly; Di Stefano, Julian; Christie, Fiona; Swan, Matthew; York, Alan

2016-01-01

Animal species diversity is often associated with time since disturbance, but the effects of disturbances such as fire on functional diversity are unknown. Functional diversity measures the range, abundance, and distribution of trait values in a community, and links changes in species composition with the consequences for ecosystem function. Improved understanding of the relationship between time since fire (TSF) and functional diversity is critical given that the frequency of both prescribed fire and wildfire is expected to increase. To address this knowledge gap, we examined responses of avian functional diversity to TSF and two direct measures of environmental heterogeneity, plant diversity, and structural heterogeneity. We surveyed birds across a 70-year chronosequence spanning four vegetation types in southeast Australia. Six bird functional traits were used to derive four functional diversity indices (richness, evenness, divergence, and dispersion) and the effects of TSF, plant diversity and structural heterogeneity on species richness and the functional diversity indices were examined using mixed models. We used a regression tree method to identify traits associated with species more common in young vegetation. Functional richness and dispersion were negatively associated with TSF in all vegetation types, suggesting that recent prescribed fire generates heterogeneous vegetation and provides greater opportunities for resource partitioning. Species richness was not significantly associated with TSF, and is probably an unreliable surrogate for functional diversity in fire-prone systems. A positive, relationship between functional evenness and structural heterogeneity was comnon to all vegetation types, suggesting that fine-scale (tens of meters) structural variation can enhance ecosystem function. Species more common in young vegetation were primarily linked by their specialist diets, indicating that ecosystem services such as seed dispersal and insect control

Biodiversity, ecosystem functions and services in environmental risk assessment: introduction to the special issue.

Science.gov (United States)

Schäfer, Ralf B

2012-01-15

This Special Issue focuses on the questions if and how biodiversity, ecosystem functions and resulting services could be incorporated into the Ecological Risk Assessment (ERA). Therefore, three articles provide a framework for the integration of ecosystem services into ERA of soils, sediments and pesticides. Further articles demonstrate ways how stakeholders can be integrated into an ecosystem service-based ERA for soils and describe how the current monitoring could be adapted to new assessment endpoints that are directly linked to ecosystem services. Case studies show that the current ERA may not be protective for biodiversity, ecosystem functions and resulting services and that both pesticides and salinity currently adversely affect ecosystem functions in the field. Moreover, ecological models can be used for prediction of new protection goals and could finally support their implementation into the ERA. Overall, the Special Issue stresses the urgent need to enhance current procedures of ERA if biodiversity, ecosystem functions and resulting services are to be protected. Copyright © 2011 Elsevier B.V. All rights reserved.

Some remarks on the functions of European coastal ecosystems

NARCIS (Netherlands)

van der Maarel, E

2003-01-01

Amongst the various functions of European coastal ecosystems the information functions are by far the most important. Information is provided mainly through the various aspects of biodiversity: taxon diversity, genetic diversity, community (P) diversity, phylogentic distinctiveness, rarity and

Human impacts in African savannas are mediated by plant functional traits.

Science.gov (United States)

Osborne, Colin P; Charles-Dominique, Tristan; Stevens, Nicola; Bond, William J; Midgley, Guy; Lehmann, Caroline E R

2018-05-28

Tropical savannas have a ground cover dominated by C 4 grasses, with fire and herbivory constraining woody cover below a rainfall-based potential. The savanna biome covers 50% of the African continent, encompassing diverse ecosystems that include densely wooded Miombo woodlands and Serengeti grasslands with scattered trees. African savannas provide water, grazing and browsing, food and fuel for tens of millions of people, and have a unique biodiversity that supports wildlife tourism. However, human impacts are causing widespread and accelerating degradation of savannas. The primary threats are land cover-change and transformation, landscape fragmentation that disrupts herbivore communities and fire regimes, climate change and rising atmospheric CO 2 . The interactions among these threats are poorly understood, with unknown consequences for ecosystem health and human livelihoods. We argue that the unique combinations of plant functional traits characterizing the major floristic assemblages of African savannas make them differentially susceptible and resilient to anthropogenic drivers of ecosystem change. Research must address how this functional diversity among African savannas differentially influences their vulnerability to global change and elucidate the mechanisms responsible. This knowledge will permit appropriate management strategies to be developed to maintain ecosystem integrity, biodiversity and livelihoods. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

Using ecological production functions to link ecological processes to ecosystem services.

Science.gov (United States)

Ecological production functions (EPFs) link ecosystems, stressors, and management actions to ecosystem services (ES) production. Although EPFs are acknowledged as being essential to improve environmental management, their use in ecological risk assessment has received relatively ...

Same pattern, different mechanism: Locking onto the role of key species in seafloor ecosystem process.

Science.gov (United States)

Woodin, Sarah Ann; Volkenborn, Nils; Pilditch, Conrad A; Lohrer, Andrew M; Wethey, David S; Hewitt, Judi E; Thrush, Simon F

2016-05-27

Seafloor biodiversity is a key mediator of ecosystem functioning, but its role is often excluded from global budgets or simplified to black boxes in models. New techniques allow quantification of the behavior of animals living below the sediment surface and assessment of the ecosystem consequences of complex interactions, yielding a better understanding of the role of seafloor animals in affecting key processes like primary productivity. Combining predictions based on natural history, behavior of key benthic species and environmental context allow assessment of differences in functioning and process, even when the measured ecosystem property in different systems is similar. Data from three sedimentary systems in New Zealand illustrate this. Analysis of the behaviors of the infaunal ecosystem engineers in each system revealed three very different mechanisms driving ecosystem function: density and excretion, sediment turnover and surface rugosity, and hydraulic activities and porewater bioadvection. Integrative metrics of ecosystem function in some cases differentiate among the systems (gross primary production) and in others do not (photosynthetic efficiency). Analyses based on behaviors and activities revealed important ecosystem functional differences and can dramatically improve our ability to model the impact of stressors on ecosystem and global processes.

Re-introducing environmental change drivers in biodiversity-ecosystem functioning research

Science.gov (United States)

De Laender, Frederik; Rohr, Jason R.; Ashauer, Roman; Baird, Donald J.; Berger, Uta; Eisenhauer, Nico; Grimm, Volker; Hommen, Udo; Maltby, Lorraine; Meliàn, Carlos J.; Pomati, Francesco; Roessink, Ivo; Radchuk, Viktoriia; Van den Brink, Paul J.

2016-01-01

For the past 20 years, research on biodiversity and ecosystem functioning (B-EF) has only implicitly considered the underlying role of environmental change. We illustrate that explicitly re-introducing environmental change drivers in B-EF research is needed to predict the functioning of ecosystems facing changes in biodiversity. Next, we show how this reintroduction improves experimental control over community composition and structure, which helps to obtain mechanistic insight about how multiple aspects of biodiversity relate to function, and how biodiversity and function relate in food-webs. We also highlight challenges for the proposed re-introduction, and suggest analyses and experiments to better understand how random biodiversity changes, as studied by classic approaches in B-EF research, contribute to the shifts in function that follow environmental change. PMID:27742415

Biodiversity and ecosystem functioning in dynamic landscapes

Science.gov (United States)

Brose, Ulrich; Hillebrand, Helmut

2016-01-01

The relationship between biodiversity and ecosystem functioning (BEF) and its consequence for ecosystem services has predominantly been studied by controlled, short-term and small-scale experiments under standardized environmental conditions and constant community compositions. However, changes in biodiversity occur in real-world ecosystems with varying environments and a dynamic community composition. In this theme issue, we present novel research on BEF in such dynamic communities. The contributions are organized in three sections on BEF relationships in (i) multi-trophic diversity, (ii) non-equilibrium biodiversity under disturbance and varying environmental conditions, and (iii) large spatial and long temporal scales. The first section shows that multi-trophic BEF relationships often appear idiosyncratic, while accounting for species traits enables a predictive understanding. Future BEF research on complex communities needs to include ecological theory that is based on first principles of species-averaged body masses, stoichiometry and effects of environmental conditions such as temperature. The second section illustrates that disturbance and varying environments have direct as well as indirect (via changes in species richness, community composition and species' traits) effects on BEF relationships. Fluctuations in biodiversity (species richness, community composition and also trait dominance within species) can severely modify BEF relationships. The third section demonstrates that BEF at larger spatial scales is driven by different variables. While species richness per se and community biomass are most important, species identity effects and community composition are less important than at small scales. Across long temporal scales, mass extinctions represent severe changes in biodiversity with mixed effects on ecosystem functions. Together, the contributions of this theme issue identify new research frontiers and answer some open questions on BEF relationships

Integrating the provision of ecosystem services and trawl fisheries for the management of the marine environment.

Science.gov (United States)

Muntadas, Alba; de Juan, Silvia; Demestre, Montserrat

2015-02-15

The species interaction and their biological traits (BT) determine the function of benthic communities and, hence, the delivery of ecosystem services. Therefore, disturbance of benthic communities by trawling may compromise ecosystem service delivery, including fisheries' catches. In this work, we explore 1) the impact of trawling activities on benthic functional components (after the BTA approach) and 2) how trawling impact may affect the ecosystem services delivered by benthic communities. To this aim, we assessed the provision of ecosystem services by adopting the concept of Ecosystem Service Providers (ESP), i.e. ecological units that perform ecosystem functions that will ultimately deliver ecosystem services. We studied thirteen sites subjected to different levels of fishing effort in the Mediterranean. From a range of environmental variables included in the study, we found ESPs to be mainly affected by fishing effort and grain size. Our results suggested that habitat type has significant effects on the distribution of ESPs and this natural variability influences ESP response to trawling at a specific site. In order to summarize the complex relationships between human uses, ecosystem components and the demand for ecosystem services in trawling grounds, we adapted a DPSIR (Drivers-Pressures-State Change-Impact-Response) framework to the study area, emphasizing the role of society as Drivers of change and actors demanding management Responses. This integrative framework aims to inform managers about the interactions between all the elements involved in the management of trawling grounds, highlighting the need for an integrated approach in order to ensure ecosystem service provision. Copyright © 2014 Elsevier B.V. All rights reserved.

Disproportionate Declines in Ground-Foraging Insectivorous Birds after Mistletoe Removal.

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David M Watson

Full Text Available Insectivorous birds have been recognized as disproportionately sensitive to land-use intensification and habitat loss, with those species feeding primarily on the ground exhibiting some of the most dramatic declines. Altered litter inputs and availability of epigeic arthropods have been suggested to underlie reduced abundances and shrinking distributions but direct evidence is lacking. I used a patch-scale removal experiment in southern Australia to evaluate whether ground-feeding insectivores are especially vulnerable to altered litter-fall. Building on work demonstrating the importance of mistletoe litter to nutrient dynamics, litter was reduced by removing mistletoe (Loranthaceae from one set of eucalypt woodlands, responses of birds three years after mistletoe removal compared with otherwise similar control woodlands containing mistletoe. Despite not feeding on mistletoes directly, insectivores exhibited the greatest response to mistletoe removal. Among woodland residents, ground-foraging insectivores showed the most dramatic response; treatment woodlands losing an average of 37.4% of their pre-treatment species richness. Once these 19 species of ground-foraging insectivores were excluded, remaining woodland species showed no significant effect of mistletoe removal. This response reflects greater initial losses in treatment woodlands during the study (which coincided with a severe drought and double the number of species returning to control woodlands (where mistletoe numbers and litter were not manipulated post-drought. These findings support the productivity-based explanation of declining insectivores, suggesting diminished litter-fall reduced habitat quality for these birds via decreased availability of their preferred prey. In addition to altered prey availability, interactions between litter-fall and epigeic arthropods exemplify the importance of below-ground / above-ground linkages driving ecosystem function.

Plant functional traits and diversity in sand dune ecosystems across different biogeographic regions

Science.gov (United States)

Mahdavi, P.; Bergmeier, E.

2016-07-01

Plant species of a functional group respond similarly to environmental pressures and may be expected to act similarly on ecosystem processes and habitat properties. However, feasibility and applicability of functional groups in ecosystems across very different climatic regions have not yet been studied. In our approach we specified the functional groups in sand dune ecosystems of the Mediterranean, Hyrcanian and Irano-Turanian phytogeographic regions. We examined whether functional groups are more influenced by region or rather by habitat characteristics, and identified trait syndromes associated with common habitat types in sand dunes (mobile dunes, stabilized dunes, salt marshes, semi-wet sands, disturbed habitats). A database of 14 traits, 309 species and 314 relevés was examined and trait-species, trait-plot and species-plot matrices were built. Cluster analysis revealed similar plant functional groups in sand dune ecosystems across regions of very different species composition and climate. Specifically, our study showed that plant traits in sand dune ecosystems are grouped reflecting habitat affiliation rather than region and species pool. Environmental factors and constraints such as sand mobility, soil salinity, water availability, nutrient status and disturbance are more important for the occurrence and distribution of plant functional groups than regional belonging. Each habitat is shown to be equipped with specific functional groups and can be described by specific sets of traits. In restoration ecology the completeness of functional groups and traits in a site may serve as a guideline for maintaining or restoring the habitat.

A comparative study on nutrient cycling in wet heathland ecosystems : II. Litter decomposition and nutrient mineralization.

Science.gov (United States)

Berendse, Frank; Bobbink, Roland; Rouwenhorst, Gerrit

1989-03-01

The concept of the relative nutrient requirement (L n ) that was introduced in the first paper of this series is used to analyse the effects of the dominant plant population on nutrient cycling and nutrient mineralization in wet heathland ecosystems. A distinction is made between the effect that the dominant plant species has on (1) the distribution of nutrients over the plant biomass and the soil compartment of the ecosystem and (2) the recirculation rate of nutrients. The first effect of the dominant plant species can be calculated on the basis of the δ/k ratio (which is the ratio of the relative mortality to the decomposition constant). The second effect can be analysed using the relative nutrient requirement (L n ). The mass loss and the changes in the amounts of N and P in decomposing above-ground and below-ground litter produced by Erica tetralix and Molinia caerulea were measured over three years. The rates of mass loss from both above-ground and below-ground litter of Molinia were higher than those from Erica litter. After an initial leaching phase, litter showed either a net release or a net immobilization of nitrogen or phosphorus that depended on the initial concentrations of these nutrients. At the same sites, mineralization of nitrogen and phosphorus were measured for two years both in communities dominated by Molinia and in communities dominated by Erica. There were no clear differences in the nitrogen mineralization, but in one of the two years, phosphate mineralization in the Molinia-community was significantly higher. On the basis of the theory that was developed, mineralization rates and ratios between amounts of nutrients in plant biomass and in the soil were calculated on the basis of parameters that were independently measured. There was a reasonable agreement between predicted and measured values in the Erica-communities. In the Molinia-communities there were large differences between calculated and measured values, which was explained by the

Endangered species management and ecosystem restoration: Finding the common ground

Science.gov (United States)

Casazza, Michael L.; Overton, Cory T.; Bui, Thuy-Vy D.; Hull, Joshua M.; Albertson, Joy D.; Bloom, Valary K.; Bobzien, Steven; McBroom, Jennifer; Latta, Marilyn; Olofson, Peggy; Rohmer, Tobias M.; Schwarzbach, Steven E.; Strong, Donald R.; Grijalva, Erik; Wood, Julian K.; Skalos, Shannon; Takekawa, John Y.

2016-01-01

Management actions to protect endangered species and conserve ecosystem function may not always be in precise alignment. Efforts to recover the California Ridgway’s Rail (Rallus obsoletus obsoletus; hereafter, California rail), a federally and state-listed species, and restoration of tidal marsh ecosystems in the San Francisco Bay estuary provide a prime example of habitat restoration that has conflicted with species conservation. On the brink of extinction from habitat loss and degradation, and non-native predators in the 1990s, California rail populations responded positively to introduction of a non-native plant, Atlantic cordgrass (Spartina alterniflora). California rail populations were in substantial decline when the non-native Spartina was initially introduced as part of efforts to recover tidal marshes. Subsequent hybridization with the native Pacific cordgrass (Spartina foliosa) boosted California rail populations by providing greater cover and increased habitat area. The hybrid cordgrass (S. alterniflora × S. foliosa) readily invaded tidal mudflats and channels, and both crowded out native tidal marsh plants and increased sediment accretion in the marsh plain. This resulted in modification of tidal marsh geomorphology, hydrology, productivity, and species composition. Our results show that denser California rail populations occur in invasive Spartina than in native Spartina in San Francisco Bay. Herbicide treatment between 2005 and 2012 removed invasive Spartina from open intertidal mud and preserved foraging habitat for shorebirds. However, removal of invasive Spartina caused substantial decreases in California rail populations. Unknown facets of California rail ecology, undesirable interim stages of tidal marsh restoration, and competing management objectives among stakeholders resulted in management planning for endangered species or ecosystem restoration that favored one goal over the other. We have examined this perceived conflict and propose

Endangered species management and ecosystem restoration: finding the common ground

Directory of Open Access Journals (Sweden)

Michael L. Casazza

2016-03-01

Full Text Available Management actions to protect endangered species and conserve ecosystem function may not always be in precise alignment. Efforts to recover the California Ridgway's Rail (Rallus obsoletus obsoletus; hereafter, California rail, a federally and state-listed species, and restoration of tidal marsh ecosystems in the San Francisco Bay estuary provide a prime example of habitat restoration that has conflicted with species conservation. On the brink of extinction from habitat loss and degradation, and non-native predators in the 1990s, California rail populations responded positively to introduction of a non-native plant, Atlantic cordgrass (Spartina alterniflora. California rail populations were in substantial decline when the non-native Spartina was initially introduced as part of efforts to recover tidal marshes. Subsequent hybridization with the native Pacific cordgrass (Spartina foliosa boosted California rail populations by providing greater cover and increased habitat area. The hybrid cordgrass (S. alterniflora à - S. foliosa readily invaded tidal mudflats and channels, and both crowded out native tidal marsh plants and increased sediment accretion in the marsh plain. This resulted in modification of tidal marsh geomorphology, hydrology, productivity, and species composition. Our results show that denser California rail populations occur in invasive Spartina than in native Spartina in San Francisco Bay. Herbicide treatment between 2005 and 2012 removed invasive Spartina from open intertidal mud and preserved foraging habitat for shorebirds. However, removal of invasive Spartina caused substantial decreases in California rail populations. Unknown facets of California rail ecology, undesirable interim stages of tidal marsh restoration, and competing management objectives among stakeholders resulted in management planning for endangered species or ecosystem restoration that favored one goal over the other. We have examined this perceived conflict

Chapter Four : Towards an Integration of Biodiversity–Ecosystem Functioning and Food Web Theory to Evaluate Relationships between Multiple Ecosystem Services

NARCIS (Netherlands)

Hines, J.; Putten, van der W.H.; Deyn, de G.B.; Wagg, C.; Voigt, W.; Mulder, C.; Weisser, W.W.; Engel, J.; Melian, C.; Scheu, S.; Birkhofer, K.; Ebeling, A.; Scherber, C.; Eisenhauer, N.

2015-01-01

Ecosystem responses to changes in species diversity are often studied individually. However, changes in species diversity can simultaneously influence multiple interdependent ecosystem functions. Therefore, an important challenge is to determine when and how changes in species diversity that

Current uses of ground penetrating radar in groundwater-dependent ecosystems research.

Science.gov (United States)

Paz, Catarina; Alcalá, Francisco J; Carvalho, Jorge M; Ribeiro, Luís

2017-10-01

Ground penetrating radar (GPR) is a high-resolution technique widely used in shallow groundwater prospecting. This makes GPR ideal to characterize the hydrogeological functioning of groundwater-dependent ecosystems (GDE). This paper reviews current uses of GPR in GDE research through the construction of a database comprising 91 worldwide GPR case studies selected from the literature and classified according to (1) geological environments favouring GDE; (2) hydrogeological research interests; and (3) field technical and (4) hydrogeological conditions of the survey. The database analysis showed that inland alluvial, colluvial, and glacial formations were the most widely covered geological environments. Water-table depth was the most repeated research interest. By contrast, weathered-marl and crystalline-rock environments as well as the delineation of salinity interfaces in coastal and inland areas were less studied. Despite that shallow groundwater propitiated GDE in almost all the GPR case studies compiled, only one case expressly addressed GDE research. Common ranges of prospecting depth, water-table depth, and volumetric water content deduced by GPR and other techniques were identified. Antenna frequency of 100MHz and the common offset acquisition technique predominated in the database. Most of GPR case studies were in 30-50° N temperate latitudes, mainly in Europe and North America. Eight original radargrams were selected from several GPR profiles performed in 2014 and 2015 to document database classes and identified gaps, as well as to define experimental ranges of operability in GDE environments. The results contribute to the design of proper GPR surveys in GDE research. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling Water and Nutrient Transport through the Soil-Root-Canopy Continuum: Explicitly Linking the Below- and Above-Ground Processes

Science.gov (United States)

Kumar, P.; Quijano, J. C.; Drewry, D.

2010-12-01

Vegetation roots provide a fundamental link between the below ground water and nutrient dynamics and above ground canopy processes such as photosynthesis, evapotranspiration and energy balance. The “hydraulic architecture” of roots, consisting of the structural organization of the root system and the flow properties of the conduits (xylem) as well as interfaces with the soil and the above ground canopy, affect stomatal conductance thereby directly linking them to the transpiration. Roots serve as preferential pathways for the movement of moisture from wet to dry soil layers during the night, both from upper soil layer to deeper layers during the wet season (‘hydraulic descent’) and vice-versa (‘hydraulic lift’) as determined by the moisture gradients. The conductivities of transport through the root system are significantly, often orders of magnitude, larger than that of the surrounding soil resulting in movement of soil-moisture at rates that are substantially larger than that through the soil. This phenomenon is called hydraulic redistribution (HR). The ability of the deep-rooted vegetation to “bank” the water through hydraulic descent during wet periods for utilization during dry periods provides them with a competitive advantage. However, during periods of hydraulic lift these deep-rooted trees may facilitate the growth of understory vegetation where the understory scavenges the hydraulically lifted soil water. In other words, understory vegetation with relatively shallow root systems have access to the banked deep-water reservoir. These inter-dependent root systems have a significant influence on water cycle and ecosystem productivity. HR induced available moisture may support rhizosphere microbial and mycorrhizal fungi activities and enable utilization of heterogeneously distributed water and nutrient resources To capture this complex inter-dependent nutrient and water transport through the soil-root-canopy continuum we present modeling

Nine endangered taxa, one recovering ecosystem: Identifying common ground for recovery on Santa Cruz Island, California

Science.gov (United States)

McEachern, A. Kathryn; Wilken, Dieter H.

2011-01-01

It is not uncommon to have several rare and listed taxa occupying habitats in one landscape or management area where conservation amounts to defense against the possibility of further loss. It is uncommon and extremely exciting, however, to have several listed taxa occupying one island that is managed cooperatively for conservation and recovery. On Santa Cruz Island, the largest of the northern California island group in the Santa Barbara Channel, we have a golden opportunity to marry ecological knowledge and institutional "good will" in a field test of holistic rare plant conservation. Here, the last feral livestock have been removed, active weed control is underway, and management is focused on understanding and demonstrating system response to conservation management. Yet funding limitations still exist and we need to plan the most fiscally conservative and marketable approach to rare plant restoration. We still experience the tension between desirable quick results and the ecological pace of system recovery. Therefore, our research has focused on identifying fundamental constraints on species recovery at individual, demographic, habitat, and ecosystem levels, and then developing suites of actions that might be taken across taxa and landscapes. At the same time, we seek a performance middle ground that balances an institutional need for quick demonstration of hands-on positive results with a contrasting approach that allows ecosystem recovery to facilitate species recovery in the long term. We find that constraints vary across breeding systems, life-histories, and island locations. We take a hybrid approach in which we identify several actions that we can take now to enhance population size or habitat occupancy for some taxa by active restoration, while allowing others to recover at the pace of ecosystem change. We make our recommendations on the basis of data we have collected over the last decade, so that management is firmly grounded in ecological observation.

Analysis of the soil food web structure under grass and grass clover

NARCIS (Netherlands)

Eekeren, van N.J.M.; Smeding, F.W.; Vries, de F.T.; Bloem, J.

2006-01-01

The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil

Disturbance, Functional Diversity and Ecosystem Processes: Does Species Identity Matter?

OpenAIRE

Emrick III, Verl Roy

2013-01-01

The role of disturbance is widely recognized as a fundamental driver of ecological organization from individual species to entire landscapes. Anthropogenic disturbances from military training provide a unique opportunity to examine effects of disturbance on vegetation dynamics, physicochemical soil properties, and ecosystem processes. Additionally, plant functional diversity has been suggested as the key to ecosystem processes such as productivity and nutrient dynamics. I investigated how dis...

Balance matters : N:P stoichiometry and plant diversity in grassland ecosystems

NARCIS (Netherlands)

Fujita, Y.

2010-01-01

Eutrophication of Nitrogen (N) and Phosphorus (P) is threatening the functioning and biodiversity of grassland ecosystems. A well known effect of eutrophication on grasslands is an increase of above-ground productivity, which intensifies light competition and allows only a few competitive species to

Shifts of community composition and population density substantially affect ecosystem function despite invariant richness

NARCIS (Netherlands)

Spaak, Jurg W.; Baert, Jan M.; Baird, Donald J.; Eisenhauer, Nico; Maltby, Lorraine; Pomati, Francesco; Radchuk, Viktoriia; Rohr, Jason R.; Brink, van den Paul J.; Laender, De Frederik

2017-01-01

There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community

Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

Science.gov (United States)

Mestdagh, Sebastiaan; Bagaço, Leila; Braeckman, Ulrike; Ysebaert, Tom; De Smet, Bart; Moens, Tom; Van Colen, Carl

2018-05-01

Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater-bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the

Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

Directory of Open Access Journals (Sweden)

S. Mestdagh

2018-05-01

Full Text Available Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC. An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands. The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our

Climatological Implications of Deep-Rooting in Water-Limited Ecosystems

Science.gov (United States)

Amenu, G. G.; Kumar, P.

2005-12-01

In vegetated ecosystems, plants are the primary channels that connect the soil with the atmosphere (through water, energy, carbon, and nutrient cycles), with plant roots controlling the below-ground dynamics. Recently, several observational evidences are emerging which suggests the existence of plant roots much deeper in the soil/rock profile than the depth usually perceived in existing hydroclimatological and hydroecological models. In this study, using land surface model, we assess the effects of vegetation deep-rooting on (a) moisture and temperature redistribution in the soil profile, (b) energy flux partitioning at the land surface, and (c) net primary productivity of vegetated ecosystems. Three sites characterized by different vegetation, soil, and climate (all located in arid to sub-humid regions of the United States) were studied. The sites include the Mogollon Rim in Arizona, the Edwards Plateau in Texas, and the Southern Piedmont in Georgia. Soil depths of up to 10 m are investigated. Results of this modeling effort and its implications for climatological modeling will be presented.

Partitioning inter annual variability in net ecosystem exchange between climatic variability and functional change

International Nuclear Information System (INIS)

Hui, D.; Luo, Y.; Katul, G.

2003-01-01

Inter annual variability in net ecosystem exchange of carbon is investigated using a homogeneity-of-slopes model to identify the function change contributing to inter annual variability, net ecosystem carbon exchange, and night-time ecosystem respiration. Results of employing this statistical approach to a data set collected at the Duke Forest AmeriFlux site from August 1997 to December 2001 are discussed. The results demonstrate that it is feasible to partition the variation in ecosystem carbon fluxes into direct effects of seasonal and inter annual climatic variability and functional change. 51 refs., 4 tabs., 5 figs

Environmental and Human Controls of Ecosystem Functional Diversity in Temperate South America

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Domingo Alcaraz-Segura

2013-01-01

Full Text Available The regional controls of biodiversity patterns have been traditionally evaluated using structural and compositional components at the species level, but evaluation of the functional component at the ecosystem level is still scarce. During the last decades, the role of ecosystem functioning in management and conservation has increased. Our aim was to use satellite-derived Ecosystem Functional Types (EFTs, patches of the land-surface with similar carbon gain dynamics to characterize the regional patterns of ecosystem functional diversity and to evaluate the environmental and human controls that determine EFT richness across natural and human-modified systems in temperate South America. The EFT identification was based on three descriptors of carbon gain dynamics derived from seasonal curves of the MODIS Enhanced Vegetation Index (EVI: annual mean (surrogate of primary production, seasonal coefficient of variation (indicator of seasonality and date of maximum EVI (descriptor of phenology. As observed for species richness in the southern hemisphere, water availability, not energy, emerged as the main climatic driver of EFT richness in natural areas of temperate South America. In anthropogenic areas, the role of both water and energy decreased and increasing human intervention increased richness at low levels of human influence, but decreased richness at high levels of human influence.

Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China, 2004-2010.

Science.gov (United States)

Zhang, Xinyu; Xu, Zhiwei; Sun, Xiaomin; Dong, Wenyi; Ballantine, Deborah

2013-05-01

The nitrate-nitrogen (NO3(-)-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations, representing typical agro- and forest ecosystems, were assessed using monitoring data collected between 2004 and 2010. Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater, and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made. Results indicated that most of the NO3(-)-N concentrations in groundwater from the agro- and forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard: Quality Standard for Ground Water (ecosystems (4.1 +/- 0.33 mg/L) than in forest ecosystems (0.5 +/- 0.04 mg/L). NO3(-)-N concentrations were relatively higher (> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems. These elevated concentrations occurred mainly in the Ansai, Yucheng, Linze, Fukang, Akesu, and Cele field sites, which were located in arid and semi-arid areas where irrigation rates are high. We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.

Identifying priority areas for ecosystem service management in South African grasslands.

Science.gov (United States)

Egoh, Benis N; Reyers, Belinda; Rouget, Mathieu; Richardson, David M

2011-06-01

Grasslands provide many ecosystem services required to support human well-being and are home to a diverse fauna and flora. Degradation of grasslands due to agriculture and other forms of land use threaten biodiversity and ecosystem services. Various efforts are underway around the world to stem these declines. The Grassland Programme in South Africa is one such initiative and is aimed at safeguarding both biodiversity and ecosystem services. As part of this developing programme, we identified spatial priority areas for ecosystem services, tested the effect of different target levels of ecosystem services used to identify priority areas, and evaluated whether biodiversity priority areas can be aligned with those for ecosystem services. We mapped five ecosystem services (below ground carbon storage, surface water supply, water flow regulation, soil accumulation and soil retention) and identified priority areas for individual ecosystem services and for all five services at the scale of quaternary catchments. Planning for individual ecosystem services showed that, depending on the ecosystem service of interest, between 4% and 13% of the grassland biome was required to conserve at least 40% of the soil and water services. Thirty-four percent of the biome was needed to conserve 40% of the carbon service in the grassland. Priority areas identified for five ecosystem services under three target levels (20%, 40%, 60% of the total amount) showed that between 17% and 56% of the grassland biome was needed to conserve these ecosystem services. There was moderate to high overlap between priority areas selected for ecosystem services and already-identified terrestrial and freshwater biodiversity priority areas. This level of overlap coupled with low irreplaceability values obtained when planning for individual ecosystem services makes it possible to combine biodiversity and ecosystem services in one plan using systematic conservation planning. Copyright © 2011 Elsevier Ltd. All

Microbes as engines of ecosystem function: when does community structure enhance predictions of ecosystem processes?

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Emily B. Graham

2016-02-01

Full Text Available Microorganisms are vital in mediating the earth’s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: ‘When do we need to understand microbial community structure to accurately predict function?’ We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.

The warm dark matter halo mass function below the cut-off scale

Science.gov (United States)

Angulo, Raul E.; Hahn, Oliver; Abel, Tom

2013-10-01

Warm dark matter (WDM) cosmologies are a viable alternative to the cold dark matter (CDM) scenario. Unfortunately, an accurate scrutiny of the WDM predictions with N-body simulations has proven difficult due to numerical artefacts. Here, we report on cosmological simulations that, for the first time, are devoid of those problems, and thus are able to accurately resolve the WDM halo mass function well below the cut-off. We discover a complex picture, with perturbations at different evolutionary stages populating different ranges in the halo mass function. On the smallest mass scales we can resolve, identified objects are typically centres of filaments that are starting to collapse. On intermediate mass scales, objects typically correspond to fluctuations that have collapsed and are in the process of relaxation, whereas the high-mass end is dominated by objects similar to haloes identified in CDM simulations. We then explicitly show how the formation of low-mass haloes is suppressed, which translates into a strong cut-off in the halo mass function. This disfavours some analytic formulations that predict a halo mass function that would extend well below the free streaming mass. We argue for a more detailed exploration of the formation of the smallest structures expected to form in a given cosmology, which, we foresee, will advance our overall understanding of structure formation.

Global biodiversity, stoichiometry and ecosystem function responses to human-induced C-N-P imbalances.

Science.gov (United States)

Carnicer, Jofre; Sardans, Jordi; Stefanescu, Constantí; Ubach, Andreu; Bartrons, Mireia; Asensio, Dolores; Peñuelas, Josep

2015-01-01

Global change analyses usually consider biodiversity as a global asset that needs to be preserved. Biodiversity is frequently analysed mainly as a response variable affected by diverse environmental drivers. However, recent studies highlight that gradients of biodiversity are associated with gradual changes in the distribution of key dominant functional groups characterized by distinctive traits and stoichiometry, which in turn often define the rates of ecosystem processes and nutrient cycling. Moreover, pervasive links have been reported between biodiversity, food web structure, ecosystem function and species stoichiometry. Here we review current global stoichiometric gradients and how future distributional shifts in key functional groups may in turn influence basic ecosystem functions (production, nutrient cycling, decomposition) and therefore could exert a feedback effect on stoichiometric gradients. The C-N-P stoichiometry of most primary producers (phytoplankton, algae, plants) has been linked to functional trait continua (i.e. to major axes of phenotypic variation observed in inter-specific analyses of multiple traits). In contrast, the C-N-P stoichiometry of higher-level consumers remains less precisely quantified in many taxonomic groups. We show that significant links are observed between trait continua across trophic levels. In spite of recent advances, the future reciprocal feedbacks between key functional groups, biodiversity and ecosystem functions remain largely uncertain. The reported evidence, however, highlights the key role of stoichiometric traits and suggests the need of a progressive shift towards an ecosystemic and stoichiometric perspective in global biodiversity analyses. Copyright © 2014 Elsevier GmbH. All rights reserved.

Biological factors of natural and artificial ecosystems stable (unstable) functioning

Science.gov (United States)

Pechurkin, Nikolai S.

The problem of sustainable development of humanity on Earth and the problem of supporting human life in space have the same scientific and methodological bases. The key to solve both problems is a long term maintenance of balanced material cycle. As a whole, natural or artificial ecosystems are to be more closed than open, but their elements (links of systems) are to be substantially open in interactions with each other. Prolonged stable interactions of different links have to have unique joint results - closed material cycling or biotic turnover. It is necessary to include, at least, three types of main links into any system to support real material cycling: producers, consumers, reducers. Producer links are now under studies in many laboratories. It is evident that the higher productivity of link, the lower link stability. Especially, it concerns with parasite impact to plants. As usual, artificial ecosystems are more simple (incomplete) than natural ecosystems, sometimes, they have not enough links for prolonged stable functioning. For example, life support system for space flight can be incomplete in consumer link, having only some crew persons, instead of interacting populations of consumers. As for reducer link, it is necessary to "organize" a special coordinated work of microbial biocenoses to fulfill proper cycling. Possible evolution of links, their self development is a matter of special attention for the maintenance of prolonged stable functioning. It's the most danger for systems with populations of quickly reproducing, so-called, R - strategists, according to symbols of logistic equation. From another side, quick reproduction of R - strategists is able to increase artificial ecosystems and their links functioning. After some damages of system, R - strategist's link can be quickly "self repaired" up to level of normal functioning. Some experimental data of this kind and mathematical models are to be discussed in the paper. This work is supported by

A review of the ecosystem functions in oil palm plantations, using forests as a reference system.

Science.gov (United States)

Dislich, Claudia; Keyel, Alexander C; Salecker, Jan; Kisel, Yael; Meyer, Katrin M; Auliya, Mark; Barnes, Andrew D; Corre, Marife D; Darras, Kevin; Faust, Heiko; Hess, Bastian; Klasen, Stephan; Knohl, Alexander; Kreft, Holger; Meijide, Ana; Nurdiansyah, Fuad; Otten, Fenna; Pe'er, Guy; Steinebach, Stefanie; Tarigan, Suria; Tölle, Merja H; Tscharntke, Teja; Wiegand, Kerstin

2017-08-01

Oil palm plantations have expanded rapidly in recent decades. This large-scale land-use change has had great ecological, economic, and social impacts on both the areas converted to oil palm and their surroundings. However, research on the impacts of oil palm cultivation is scattered and patchy, and no clear overview exists. We address this gap through a systematic and comprehensive literature review of all ecosystem functions in oil palm plantations, including several (genetic, medicinal and ornamental resources, information functions) not included in previous systematic reviews. We compare ecosystem functions in oil palm plantations to those in forests, as the conversion of forest to oil palm is prevalent in the tropics. We find that oil palm plantations generally have reduced ecosystem functioning compared to forests: 11 out of 14 ecosystem functions show a net decrease in level of function. Some functions show decreases with potentially irreversible global impacts (e.g. reductions in gas and climate regulation, habitat and nursery functions, genetic resources, medicinal resources, and information functions). The most serious impacts occur when forest is cleared to establish new plantations, and immediately afterwards, especially on peat soils. To variable degrees, specific plantation management measures can prevent or reduce losses of some ecosystem functions (e.g. avoid illegal land clearing via fire, avoid draining of peat, use of integrated pest management, use of cover crops, mulch, and compost) and we highlight synergistic mitigation measures that can improve multiple ecosystem functions simultaneously. The only ecosystem function which increases in oil palm plantations is, unsurprisingly, the production of marketable goods. Our review highlights numerous research gaps. In particular, there are significant gaps with respect to socio-cultural information functions. Further, there is a need for more empirical data on the importance of spatial and temporal

Microbial ecology of fermentative hydrogen producing bioprocesses: useful insights for driving the ecosystem function.

Science.gov (United States)

Cabrol, Lea; Marone, Antonella; Tapia-Venegas, Estela; Steyer, Jean-Philippe; Ruiz-Filippi, Gonzalo; Trably, Eric

2017-03-01

One of the most important biotechnological challenges is to develop environment friendly technologies to produce new sources of energy. Microbial production of biohydrogen through dark fermentation, by conversion of residual biomass, is an attractive solution for short-term development of bioH2 producing processes. Efficient biohydrogen production relies on complex mixed communities working in tight interaction. Species composition and functional traits are of crucial importance to maintain the ecosystem service. The analysis of microbial community revealed a wide phylogenetic diversity that contributes in different-and still mostly unclear-ways to hydrogen production. Bridging this gap of knowledge between microbial ecology features and ecosystem functionality is essential to optimize the bioprocess and develop strategies toward a maximization of the efficiency and stability of substrate conversion. The aim of this review is to provide a comprehensive overview of the most up-to-date biodata available and discuss the main microbial community features of biohydrogen engineered ecosystems, with a special emphasis on the crucial role of interactions and the relationships between species composition and ecosystem service. The elucidation of intricate relationships between community structure and ecosystem function would make possible to drive ecosystems toward an improved functionality on the basis of microbial ecology principles. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The estimate of ecological risk for ground ecosystems in case of nuclear power plant failures

International Nuclear Information System (INIS)

Kremlenkov, D.Y.; Kremlenkov, M.Y.

2003-01-01

Full text: The stochastic nature of radiation damage generates a need of forecasting information about possible consequences for environment and people. In this article it is given the estimate of probable damage to forest-and agricultural ecosystems from radionuclide emergency pollution in case of nuclear plant failures (for early emergency period). This estimate is based on radio-ecological risk conception which provide with the application of radioactive substances distribution models in atmosphere, as were calculation of absorbent radiation dose in critical ecosystem groups-calculation of probable area of lost ecosystems has been done by using the program written in Pascal. The quantitative estimate of environmental loss has been conducted for diverse classes of atmospheric stability. The value of ecological dose range (ELD) to coniferous forest is 30 Gy, deciduous forest - 300 Gy, agricultural crop - 60 Gy. The value of minimum ecological dose range (MELD) for all ecosystems is 10 Gy. In dose spread from MELD to ELD the ecological damage is proportional to absorbed dose. The ecological damage to ground ecosystems caused by cesium-137 and strontium-90 emergency pollution is primarily depended on the scale of radionuclide emergency pollution as well as weather conditions and radio-stability of critical vegetal ecosystem groups. On the assumption of a dose spread from MELD to ELD, ecological risk defined in probable ecosystem's destruction area is estimated: for cesium-137 pollution about 2 % of coniferous forest and from 4 to 9 % of deciduous forest; for strontium-90 pollution from 2 to 4 % of agricultural crop. As the scale of cesium-137 emergency pollution rise from 10 4 to 10 5 Cu the probable damage determined in ecosystem's destruction area increase 12-19 times to coniferous forest ecosystem and 15-36 times to deciduous forest according to weather conditions. The probable damage to coniferous and deciduous forest rise 11-17 times in proportion as the scale

Spatial pattern enhances ecosystem functioning in an African savanna.

Directory of Open Access Journals (Sweden)

Robert M Pringle

2010-05-01

Full Text Available The finding that regular spatial patterns can emerge in nature from local interactions between organisms has prompted a search for the ecological importance of these patterns. Theoretical models have predicted that patterning may have positive emergent effects on fundamental ecosystem functions, such as productivity. We provide empirical support for this prediction. In dryland ecosystems, termite mounds are often hotspots of plant growth (primary productivity. Using detailed observations and manipulative experiments in an African savanna, we show that these mounds are also local hotspots of animal abundance (secondary and tertiary productivity: insect abundance and biomass decreased with distance from the nearest termite mound, as did the abundance, biomass, and reproductive output of insect-eating predators. Null-model analyses indicated that at the landscape scale, the evenly spaced distribution of termite mounds produced dramatically greater abundance, biomass, and reproductive output of consumers across trophic levels than would be obtained in landscapes with randomly distributed mounds. These emergent properties of spatial pattern arose because the average distance from an arbitrarily chosen point to the nearest feature in a landscape is minimized in landscapes where the features are hyper-dispersed (i.e., uniformly spaced. This suggests that the linkage between patterning and ecosystem functioning will be common to systems spanning the range of human management intensities. The centrality of spatial pattern to system-wide biomass accumulation underscores the need to conserve pattern-generating organisms and mechanisms, and to incorporate landscape patterning in efforts to restore degraded habitats and maximize the delivery of ecosystem services.

Spatial pattern enhances ecosystem functioning in an African savanna.

Science.gov (United States)

Pringle, Robert M; Doak, Daniel F; Brody, Alison K; Jocqué, Rudy; Palmer, Todd M

2010-05-25

The finding that regular spatial patterns can emerge in nature from local interactions between organisms has prompted a search for the ecological importance of these patterns. Theoretical models have predicted that patterning may have positive emergent effects on fundamental ecosystem functions, such as productivity. We provide empirical support for this prediction. In dryland ecosystems, termite mounds are often hotspots of plant growth (primary productivity). Using detailed observations and manipulative experiments in an African savanna, we show that these mounds are also local hotspots of animal abundance (secondary and tertiary productivity): insect abundance and biomass decreased with distance from the nearest termite mound, as did the abundance, biomass, and reproductive output of insect-eating predators. Null-model analyses indicated that at the landscape scale, the evenly spaced distribution of termite mounds produced dramatically greater abundance, biomass, and reproductive output of consumers across trophic levels than would be obtained in landscapes with randomly distributed mounds. These emergent properties of spatial pattern arose because the average distance from an arbitrarily chosen point to the nearest feature in a landscape is minimized in landscapes where the features are hyper-dispersed (i.e., uniformly spaced). This suggests that the linkage between patterning and ecosystem functioning will be common to systems spanning the range of human management intensities. The centrality of spatial pattern to system-wide biomass accumulation underscores the need to conserve pattern-generating organisms and mechanisms, and to incorporate landscape patterning in efforts to restore degraded habitats and maximize the delivery of ecosystem services.

Recommendations to the NRC for review criteria for alternative methods of low-level radioactive waste disposal: Task 2a, Below-ground vaults

International Nuclear Information System (INIS)

Denson, R.H.; Bennett, R.D.; Wamsley, R.M.; Bean, D.L.; Ainsworth, D.L.

1987-12-01

The US Army Engineer Waterways Experiment Station (WES) and the US Army Engineer Division, Huntsville (HNDED) have developed general design criteria and specific design review criteria for the below-ground vault (BGV) alternative method of low-level radioactive waste (LLW) disposal. A BGV is a reinforced concrete vault (floor, walls, and roof) placed underground below the frost line, and above the water table, surrounded by filter blanket and drainage zones and covered with a low permeability earth layer and top soil with vegetation. Eight major review criteria categories have been developed ranging from the loads imposed on the BGV structure through material quality and durability considerations. Specific design review criteria have been developed in detail for seven of the eight major categories. 59 refs., 14 figs., 2 tabs

Linking benthic biodiversity to the functioning of coastal ecosystems subjected to river runoff (NW Mediterranean

Directory of Open Access Journals (Sweden)

Harmelin–Vivien, M. L.

2009-12-01

Full Text Available Continental particulate organic matter (POM plays a major role in the functioning of coastal marine ecosystems as a disturbance as well as an input of nutrients. Relationships linking continental inputs from the Rhone River to biodiversity of the coastal benthic ecosystem and fishery production were investigated in the Golfe du Lion (NW Mediterranean Sea. Macrobenthic community diversity decreased when continen¬tal inputs of organic matter increased, whereas ecosystem production, measured by common sole (Solea solea fishery yields in the area, increased. Decreases in macrobenthic diversity were mainly related to an increasing abundance of species with specific functional traits, particularly deposit-feeding polychaetes. The decrease in macrobenthic diversity did not result in a decrease, but an increase in ecosystem production, as it enhanced the transfer of continental POM into marine food webs. The present study showed that it is necessary to consider functional traits of species, direct and indirect links between species, and feedback loops to understand the effects of biodiversity on ecosystem functioning and productivity.

Application of macrobenthos functional groups to estimate the ecosystem health in a semi-enclosed bay.

Science.gov (United States)

Peng, Shitao; Zhou, Ran; Qin, Xuebo; Shi, Honghua; Ding, Dewen

2013-09-15

In this study, the functional group concept was first applied to evaluate the ecosystem health of Bohai Bay. Macrobenthos functional groups were defined according to feeding types and divided into five groups: a carnivorous group (CA), omnivorous group (OM), planktivorous group (PL), herbivorous group (HE), and detritivorous group (DE). Groups CA, DE, OM, and PL were identified, but the HE group was absent from Bohai Bay. Group DE was dominant during the study periods. The ecosystem health was assessed using a functional group evenness index. The functional group evenness values of most sampling stations were less than 0.40, indicating that the ecosystem health was deteriorated in Bohai Bay. Such deterioration could be attributed to land reclamation, industrial and sewage effluents, oil pollution, and hypersaline water discharge. This study demonstrates that the functional group concept can be applied to ecosystem health assessment in a semi-enclosed bay. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of Plant Functional Group Loss on Soil Microbial Community and Litter Decomposition in a Steppe Vegetation.

Science.gov (United States)

Xiao, Chunwang; Zhou, Yong; Su, Jiaqi; Yang, Fan

2017-01-01

Globally, many terrestrial ecosystems are experiencing a rapid loss of biodiversity. Continued improvements in our understanding of interrelationships between plant diversity and soil microbes are critical to address the concern over the consequences of the decline in biodiversity on ecosystem functioning and services. By removing forbs, or grasses, or, to an extreme scenario, both forbs and grasses in a steppe vegetation in Inner Mongolia, we studied how plant functional group (PFG) loss affects soil microbial community composition using phospholipid fatty acid analysis (PLFA) and litter decomposition using a litter-bag method. PFG loss significantly decreased above- and below-ground plant biomass, soil microbial biomass carbon (SMBC) and nitrogen (SMBN), but had no effect on the ratio of SMBC to SMBN. Although the ratio of fungal to bacterial PLFAs remained unaffected, PFG loss significantly reduced the amount of bacterial, fungal, and total PLFAs. PFG loss decreased litter monthly mass loss and decay constant, and such decrease was significant when both forbs and grasses were removed. Our results provide robust evidence that PFG loss in grassland ecosystem can lead to a rapid response of soil microbial activity which may affect litter decomposition and soil nutrient cycling, suggesting that the assessment of plant-microbe interactions in soils is an integral component of ecosystem response to biodiversity loss.

Elevation alters ecosystem properties across temperate treelines globally

Science.gov (United States)

Mayor, Jordan R.; Sanders, Nathan J.; Classen, Aimée T.; Bardgett, Richard D.; Clément, Jean-Christophe; Fajardo, Alex; Lavorel, Sandra; Sundqvist, Maja K.; Bahn, Michael; Chisholm, Chelsea; Cieraad, Ellen; Gedalof, Ze'Ev; Grigulis, Karl; Kudo, Gaku; Oberski, Daniel L.; Wardle, David A.

2017-01-01

Temperature is a primary driver of the distribution of biodiversity as well as of ecosystem boundaries. Declining temperature with increasing elevation in montane systems has long been recognized as a major factor shaping plant community biodiversity, metabolic processes, and ecosystem dynamics. Elevational gradients, as thermoclines, also enable prediction of long-term ecological responses to climate warming. One of the most striking manifestations of increasing elevation is the abrupt transitions from forest to treeless alpine tundra. However, whether there are globally consistent above- and belowground responses to these transitions remains an open question. To disentangle the direct and indirect effects of temperature on ecosystem properties, here we evaluate replicate treeline ecotones in seven temperate regions of the world. We find that declining temperatures with increasing elevation did not affect tree leaf nutrient concentrations, but did reduce ground-layer community-weighted plant nitrogen, leading to the strong stoichiometric convergence of ground-layer plant community nitrogen to phosphorus ratios across all regions. Further, elevation-driven changes in plant nutrients were associated with changes in soil organic matter content and quality (carbon to nitrogen ratios) and microbial properties. Combined, our identification of direct and indirect temperature controls over plant communities and soil properties in seven contrasting regions suggests that future warming may disrupt the functional properties of montane ecosystems, particularly where plant community reorganization outpaces treeline advance.

How lichens impact on terrestrial community and ecosystem properties.

Science.gov (United States)

Asplund, Johan; Wardle, David A

2017-08-01

Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include

Microbial communities, processes and functions in acid mine drainage ecosystems.

Science.gov (United States)

Chen, Lin-xing; Huang, Li-nan; Méndez-García, Celia; Kuang, Jia-liang; Hua, Zheng-shuang; Liu, Jun; Shu, Wen-sheng

2016-04-01

Acid mine drainage (AMD) is generated from the oxidative dissolution of metal sulfides when water and oxygen are available largely due to human mining activities. This process can be accelerated by indigenous microorganisms. In the last several decades, culture-dependent researches have uncovered and validated the roles of AMD microorganisms in metal sulfides oxidation and acid generation processes, and culture-independent studies have largely revealed the diversity and metabolic potentials and activities of AMD communities, leading towards a full understanding of the microbial diversity, functions and interactions in AMD ecosystems. This review describes the diversity of microorganisms and their functions in AMD ecosystems, and discusses their biotechnological applications in biomining and AMD bioremediation according to their capabilities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Global Human Footprint on the Linkage between Biodiversity and Ecosystem Functioning in Reef Fishes

Science.gov (United States)

Mora, Camilo; Aburto-Oropeza, Octavio; Ayala Bocos, Arturo; Ayotte, Paula M.; Banks, Stuart; Bauman, Andrew G.; Beger, Maria; Bessudo, Sandra; Booth, David J.; Brokovich, Eran; Brooks, Andrew; Chabanet, Pascale; Cinner, Joshua E.; Cortés, Jorge; Cruz-Motta, Juan J.; Cupul Magaña, Amilcar; DeMartini, Edward E.; Edgar, Graham J.; Feary, David A.; Ferse, Sebastian C. A.; Friedlander, Alan M.; Gaston, Kevin J.; Gough, Charlotte; Graham, Nicholas A. J.; Green, Alison; Guzman, Hector; Hardt, Marah; Kulbicki, Michel; Letourneur, Yves; López Pérez, Andres; Loreau, Michel; Loya, Yossi; Martinez, Camilo; Mascareñas-Osorio, Ismael; Morove, Tau; Nadon, Marc-Olivier; Nakamura, Yohei; Paredes, Gustavo; Polunin, Nicholas V. C.; Pratchett, Morgan S.; Reyes Bonilla, Héctor; Rivera, Fernando; Sala, Enric; Sandin, Stuart A.; Soler, German; Stuart-Smith, Rick; Tessier, Emmanuel; Tittensor, Derek P.; Tupper, Mark; Usseglio, Paolo; Vigliola, Laurent; Wantiez, Laurent; Williams, Ivor; Wilson, Shaun K.; Zapata, Fernando A.

2011-01-01

Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas. PMID:21483714

Green function iterative solution of ground state wave function for Yukawa potential

International Nuclear Information System (INIS)

Zhang Zhao

2003-01-01

The newly developed single trajectory quadrature method is applied to solve central potentials. First, based on the series expansion method an exact analytic solution of the ground state for Hulthen potential and an approximate solution for Yukawa potential are obtained respectively. Second, the newly developed iterative method based on Green function defined by quadratures along the single trajectory is applied to solve Yukawa potential using the Coulomb solution and Hulthen solution as the trial functions respectively. The results show that a more proper choice of the trial function will give a better convergence. To further improve the convergence the iterative method is combined with the variational method to solve the ground state wave function for Yukawa potential, using variational solutions of the Coulomb and Hulthen potentials as the trial functions. The results give much better convergence. Finally, the obtained critical screen coefficient is applied to discuss the dissociate temperature of J/ψ in high temperature QGP

Non-invasive monitoring of below ground cassava storage root bulking by ground penetrating radar technology

Science.gov (United States)

Ruiz Vera, U. M.; Larson, T. H.; Mwakanyamale, K. E.; Grennan, A. K.; Souza, A. P.; Ort, D. R.; Balikian, R. J.

2017-12-01

Agriculture needs a new technological revolution to be able to meet the food demands, to overcome weather and natural hazards events, and to monitor better crop productivity. Advanced technologies used in other fields have recently been applied in agriculture. Thus, imagine instrumentation has been applied to phenotype above-ground biomass and predict yield. However, the capability to monitor belowground biomass is still limited. There are some existing technologies available, for example the ground penetrating radar (GPR) which has been used widely in the area of geology and civil engineering to detect different kind of formations under the ground without the disruption of the soil. GPR technology has been used also to monitor tree roots but as yet not crop roots. Some limitation are that the GPR cannot discern roots smaller than 2 cm in diameter, but it make it feasible for application in tuber crops like Cassava since harvest diameter is greater than 4 cm. The objective of this research is to test the availability to use GPR technology to monitor the growth of cassava roots by testing this technique in the greenhouse and in the field. So far, results from the greenhouse suggest that GPR can detect mature roots of cassava and this data could be used to predict biomass.

Seasonal & Daily Amazon Column CO2 & CO Observations from Ground & Space Used to Evaluate Tropical Ecosystem Models

Science.gov (United States)

Dubey, M. K.; Parker, H. A.; Wennberg, P. O.; Wunch, D.; Jacobson, A. R.; Kawa, S. R.; Keppel-Aleks, G.; Basu, S.; O'Dell, C.; Frankenberg, C.; Michalak, A. M.; Baker, D. F.; Christofferson, B.; Restrepo-Coupe, N.; Saleska, S. R.; De Araujo, A. C.; Miller, J. B.

2016-12-01

The Amazon basin stores 150-200 PgC, exchanges 18 PgC with the atmosphere every year and has taken up 0.42-0.65 PgC/y over the past two decades. Despite its global significance, the response of the tropical carbon cycle to climate variability and change is ill constrained as evidenced by the large negative and positive feedbacks in future climate simulations. The complex interplay of radiation, water and ecosystem phenology remains unresolved in current tropical ecosystem models. We use high frequency regional scale TCCON observations of column CO2, CO and CH4 near Manaus, Brazil that began in October 2014 to understand the aforementioned interplay of processes in regulating biosphere-atmosphere exchange. We observe a robust daily column CO2 uptake of about 2 ppm (4 ppm to 0.5 ppm) over 8 hours and evaluate how it changes as we transition to the dry season. Back-trajectory calculations show that the daily CO2 uptake footprint is terrestrial and influenced by the heterogeneity of the Amazon rain forests. The column CO falls from above 120 ppb to below 80 ppb as we transition from the biomass burning to wet seasons. The daily mean column CO2 rises by 3 ppm from October through June. Removal of biomass burning, secular CO2 increase and variations from transport (by Carbon tracker simulations) implies an increase of 2.3 ppm results from tropical biospheric processes (respiration and photosynthesis). This is consistent with ground-based remote sensing and eddy flux observations that indicate that leaf development and demography drives the tropical carbon cycle in regions that are not water limited and is not considered in current models. We compare our observations with output from 7 CO2 inversion transport models with assimilated meteorology and find that while 5 models reproduce the CO2 seasonal cycle all of them under predict the daily drawdown of CO2 by a factor of 3. This indicates that the CO2 flux partitioning between photosynthesis and respiration is incorrect

Impacts of elevated atmospheric CO2 on forest trees and forest ecosystems: knowledge gaps

International Nuclear Information System (INIS)

Karnosky, D.F.

2003-06-01

Atmospheric CO 2 is rising rapidly, and options for slowing the CO 2 rise are politically charged as they largely require reductions in industrial CO 2 emissions for most developed countries. As forests cover some 43% of the Earth's surface, account for some 70% of terrestrial net primary production (NPP), and are being bartered for carbon mitigation, it is critically important that we continue to reduce the uncertainties about the impacts of elevated atmospheric CO 2 on forest tree growth, productivity, and forest ecosystem function. In this paper, 1 review knowledge gaps and research needs on the effects of elevated atmospheric CO 2 on forest above- and below-ground growth and productivity, carbon sequestration, nutrient cycling, water relations, wood quality, phonology, community dynamics and biodiversity, antioxidants and stress tolerance, interactions with air pollutants, heterotrophic interactions, and ecosystem functioning. Finally, 1 discuss research needs regarding modelling of the impacts of elevated atmospheric CO 2 on forests. Even though there has been a tremendous amount of research done with elevated CO 2 and forest trees, it remains difficult to predict future forest growth and productivity under elevated atmospheric CO 2 . Likewise, it is not easy to predict how forest ecosystem processes will respond to enriched CO 2 . The more we study the impacts of increasing CO 2 , the more we realize that tree and forest responses are yet largely uncertain due to differences in responsiveness by species, genotype, and functional group, and the complex interactions of elevated atmospheric CO 2 with soil fertility, drought, pests, and co-occurring atmospheric pollutants such as nitrogen deposition and O 3 . Furthermore, it is impossible to predict ecosystem-level responses based on short-term studies of young trees grown without interacting stresses and in small spaces without the element of competition. Long-term studies using free-air CO 2 enrichment (FACE

Seafloor ecosystem functioning: the importance of organic matter priming

NARCIS (Netherlands)

Van Nugteren, P.; Moodley, L.; Brummer, G.J.; Heip, C.H.R.; Herman, P.M.J.; Middelburg, J.J.

2009-01-01

Organic matter (OM) remineralization may be considered a key function of the benthic compartment of marine ecosystems and in this study we investigated if the input of labile organic carbon alters mineralization of indigenous sediment OM (OM priming). Using 13C-enriched diatoms as labile tracer

Mammalian engineers drive soil microbial communities and ecosystem functions across a disturbance gradient.

Science.gov (United States)

Eldridge, David J; Delgado-Baquerizo, Manuel; Woodhouse, Jason N; Neilan, Brett A

2016-11-01

The effects of mammalian ecosystem engineers on soil microbial communities and ecosystem functions in terrestrial ecosystems are poorly known. Disturbance from livestock has been widely reported to reduce soil function, but disturbance by animals that forage in the soil may partially offset these negative effects of livestock, directly and/or indirectly by shifting the composition and diversity of soil microbial communities. Understanding the role of disturbance from livestock and ecosystem engineers in driving soil microbes and functions is essential for formulating sustainable ecosystem management and conservation policies. We compared soil bacterial community composition and enzyme concentrations within four microsites: foraging pits of two vertebrates, the indigenous short-beaked echidna (Tachyglossus aculeatus) and the exotic European rabbit (Oryctolagus cuniculus), and surface and subsurface soils along a gradient in grazing-induced disturbance in an arid woodland. Microbial community composition varied little across the disturbance gradient, but there were substantial differences among the four microsites. Echidna pits supported a lower relative abundance of Acidobacteria and Cyanobacteria, but a higher relative abundance of Proteobacteria than rabbit pits and surface microsites. Moreover, these microsite differences varied with disturbance. Rabbit pits had a similar profile to the subsoil or the surface soils under moderate and high, but not low disturbance. Overall, echidna foraging pits had the greatest positive effect on function, assessed as mean enzyme concentrations, but rabbits had the least. The positive effects of echidna foraging on function were indirectly driven via microbial community composition. In particular, increasing activity was positively associated with increasing relative abundance of Proteobacteria, but decreasing Acidobacteria. Our study suggests that soil disturbance by animals may offset, to some degree, the oft-reported negative

Delayed responses of an Arctic ecosystem to an extremely dry summer: impacts on net ecosystem exchange and vegetation functioning

Science.gov (United States)

Zona, D.; Lipson, D. A.; Richards, J. H.; Phoenix, G. K.; Liljedahl, A. K.; Ueyama, M.; Sturtevant, C. S.; Oechel, W. C.

2013-12-01

The importance and mode of action of extreme events on the global carbon budget are inadequately understood. This includes the differential impact of extreme events on various ecosystem components, lag effects, recovery times, and compensatory processes. Summer 2007 in Barrow, Arctic Alaska, experienced unusually high air temperatures (fifth warmest over a 65 yr period) and record low precipitation (lowest over a 65 yr period). These abnormal conditions resulted in strongly reduced net Sphagnum CO2 uptake, but no effect neither on vascular plant development nor on net ecosystem exchange (NEE) from this arctic tundra ecosystem. Gross primary production (GPP) and ecosystem respiration (Reco) were both generally greater during most of this extreme summer. Cumulative ecosystem C uptake in 2007 was similar to the previous summers, showing the capacity of the ecosystem to compensate in its net ecosystem exchange (NEE) despite the impact on other functions and structure such as substantial necrosis of the Sphagnum layer. Surprisingly, the lowest ecosystem C uptake (2005-2009) was observed during the 2008 summer, i.e the year directly following the extremely summer. In 2008, cumulative C uptake was ∼70% lower than prior years. This reduction cannot solely be attributed to mosses, which typically contribute with ∼40% - of the entire ecosystem C uptake. The minimum summer cumulative C uptake in 2008 suggests that the entire ecosystem experienced difficulty readjusting to more typical weather after experiencing exceptionally warm and dry conditions. Importantly, the return to a substantial cumulative C uptake occurred two summers after the extreme event, which suggest a high resilience of this tundra ecosystem. Overall, these results show a highly complex response of the C uptake and its sub-components to atypically dry conditions. The impact of multiple extreme events still awaits further investigation.

Derivation of the RPA (Random Phase Approximation) Equation of ATDDFT (Adiabatic Time Dependent Density Functional Ground State Response Theory) from an Excited State Variational Approach Based on the Ground State Functional.

Science.gov (United States)

Ziegler, Tom; Krykunov, Mykhaylo; Autschbach, Jochen

2014-09-09

The random phase approximation (RPA) equation of adiabatic time dependent density functional ground state response theory (ATDDFT) has been used extensively in studies of excited states. It extracts information about excited states from frequency dependent ground state response properties and avoids, thus, in an elegant way, direct Kohn-Sham calculations on excited states in accordance with the status of DFT as a ground state theory. Thus, excitation energies can be found as resonance poles of frequency dependent ground state polarizability from the eigenvalues of the RPA equation. ATDDFT is approximate in that it makes use of a frequency independent energy kernel derived from the ground state functional. It is shown in this study that one can derive the RPA equation of ATDDFT from a purely variational approach in which stationary states above the ground state are located using our constricted variational DFT (CV-DFT) method and the ground state functional. Thus, locating stationary states above the ground state due to one-electron excitations with a ground state functional is completely equivalent to solving the RPA equation of TDDFT employing the same functional. The present study is an extension of a previous work in which we demonstrated the equivalence between ATDDFT and CV-DFT within the Tamm-Dancoff approximation.

Biodiversity-ecosystem functioning relationships in long-term time series and palaeoecological records: deep sea as a test bed.

Science.gov (United States)

Yasuhara, Moriaki; Doi, Hideyuki; Wei, Chih-Lin; Danovaro, Roberto; Myhre, Sarah E

2016-05-19

The link between biodiversity and ecosystem functioning (BEF) over long temporal scales is poorly understood. Here, we investigate biological monitoring and palaeoecological records on decadal, centennial and millennial time scales from a BEF framework by using deep sea, soft-sediment environments as a test bed. Results generally show positive BEF relationships, in agreement with BEF studies based on present-day spatial analyses and short-term manipulative experiments. However, the deep-sea BEF relationship is much noisier across longer time scales compared with modern observational studies. We also demonstrate with palaeoecological time-series data that a larger species pool does not enhance ecosystem stability through time, whereas higher abundance as an indicator of higher ecosystem functioning may enhance ecosystem stability. These results suggest that BEF relationships are potentially time scale-dependent. Environmental impacts on biodiversity and ecosystem functioning may be much stronger than biodiversity impacts on ecosystem functioning at long, decadal-millennial, time scales. Longer time scale perspectives, including palaeoecological and ecosystem monitoring data, are critical for predicting future BEF relationships on a rapidly changing planet. © 2016 The Author(s).

The Sphagnum microbiome supports bog ecosystem functioning under extreme conditions.

Science.gov (United States)

Bragina, Anastasia; Oberauner-Wappis, Lisa; Zachow, Christin; Halwachs, Bettina; Thallinger, Gerhard G; Müller, Henry; Berg, Gabriele

2014-09-01

Sphagnum-dominated bogs represent a unique yet widely distributed type of terrestrial ecosystem and strongly contribute to global biosphere functioning. Sphagnum is colonized by highly diverse microbial communities, but less is known about their function. We identified a high functional diversity within the Sphagnum microbiome applying an Illumina-based metagenomic approach followed by de novo assembly and MG-RAST annotation. An interenvironmental comparison revealed that the Sphagnum microbiome harbours specific genetic features that distinguish it significantly from microbiomes of higher plants and peat soils. The differential traits especially support ecosystem functioning by a symbiotic lifestyle under poikilohydric and ombrotrophic conditions. To realise a plasticity-stability balance, we found abundant subsystems responsible to cope with oxidative and drought stresses, to exchange (mobile) genetic elements, and genes that encode for resistance to detrimental environmental factors, repair and self-controlling mechanisms. Multiple microbe-microbe and plant-microbe interactions were also found to play a crucial role as indicated by diverse genes necessary for biofilm formation, interaction via quorum sensing and nutrient exchange. A high proportion of genes involved in nitrogen cycle and recycling of organic material supported the role of bacteria for nutrient supply. 16S rDNA analysis indicated a higher structural diversity than that which had been previously detected using PCR-dependent techniques. Altogether, the diverse Sphagnum microbiome has the ability to support the life of the host plant and the entire ecosystem under changing environmental conditions. Beyond this, the moss microbiome presents a promising bio-resource for environmental biotechnology - with respect to novel enzymes or stress-protecting bacteria. © 2014 John Wiley & Sons Ltd.

Coupling Fine-Scale Root and Canopy Structure Using Ground-Based Remote Sensing

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Brady S. Hardiman

2017-02-01

Full Text Available Ecosystem physical structure, defined by the quantity and spatial distribution of biomass, influences a range of ecosystem functions. Remote sensing tools permit the non-destructive characterization of canopy and root features, potentially providing opportunities to link above- and belowground structure at fine spatial resolution in functionally meaningful ways. To test this possibility, we employed ground-based portable canopy LiDAR (PCL and ground penetrating radar (GPR along co-located transects in forested sites spanning multiple stages of ecosystem development and, consequently, of structural complexity. We examined canopy and root structural data for coherence (i.e., correlation in the frequency of spatial variation at multiple spatial scales ≤10 m within each site using wavelet analysis. Forest sites varied substantially in vertical canopy and root structure, with leaf area index and root mass more becoming even vertically as forests aged. In all sites, above- and belowground structure, characterized as mean maximum canopy height and root mass, exhibited significant coherence at a scale of 3.5–4 m, and results suggest that the scale of coherence may increase with stand age. Our findings demonstrate that canopy and root structure are linked at characteristic spatial scales, which provides the basis to optimize scales of observation. Our study highlights the potential, and limitations, for fusing LiDAR and radar technologies to quantitatively couple above- and belowground ecosystem structure.

Berlengas Biosphere Reserve - Plan for the assessment of ecosystem services and functions

Directory of Open Access Journals (Sweden)

Sergio Miguel Leandro

2014-05-01

Full Text Available The project Berlengas Biosphere Reserve - Plan for the Assessment of Ecosystem Services and Functions arises from the need to identify and assess ecosystem services, promoting sustainable uses of the services in the Reserve. The high degradation rate currently observed in the natural systems, thus reducing the level and quality of ecosystem services, is reflected in a negative effect on environmental quality, human well-being and in some economic activities. Thus, it becomes inevitable to promote the need to convey the importance of these services to society. It is also essential to contribute to the development of innovative and environmentally sustainable practices which will maintain the functioning of the local ecosystem and the sustainability of the services. Thus, the main goals of this project are i to identify and analyse the impacts and dependencies on ecosystem services in the Reserve; ii to analyse the trends of the priority services, iii to identify the risks and opportunities associated with these services; iv to evaluate their value and ultimately iv to disseminate the results improving conservation and management. Based on the results to be obtained through the evaluation and maintenance of these services it is expected an improvement on the environment in the region and the development of efficient mechanisms for the management of resources. Started in February 2014, over the past 3 months much research has already been conducted, with emphasis for the identification of services and opportunities in the Reserve. Ecosystem services in Berlengas can range from simply providing essential goods or support (e.g. fish to cultural services (e.g. field trips, diving. Work is also being done to develop, define and optimize the methods to assess ecosystems services trends and values.

Transfer factor of caesium-137 in natural and agricultural grass ecosystems in the area of Plavsk radioactive spot, Russia

Energy Technology Data Exchange (ETDEWEB)

Paramonova, Tatiana A.; Machaeva, Ekaterina N. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Lomonosov Moscow State University, 119234 Moscow (Russian Federation); Belyaev, Vladimir R. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Lomonosov Moscow State University, 119234 Moscow (Russian Federation)

2014-07-01

Root uptake and translocation of ¹³⁷Cs from soil to plant is the key for estimation of general ecological situation and land use on radioactive contaminated territories. There are numerous researches concerning the relationship between the level of the radionuclide presence in soils and its accumulation in vegetation that usually describes as transfer factor (TF) for ¹³⁷Cs (the ratio of the specific ¹³⁷Cs activity in the plant tissue and the soil). But in most cases only edible organs or above-ground parts of plants are taken into account in evaluating TF. It is reasonable from the standpoint of practical use, but does not provide accurate information in the study of ¹³⁷Cs biogeochemical cycle features. The study of the ¹³⁷Cs root uptake from the radioactive contaminated chernozem soil and its distribution between above-ground and below-ground fractions of grass vegetation was conducted in the natural conditions on the territory of Plavsk radioactive spot (Tula region, Russia)~25 years after Chernobyl accident. The main crops of field rotation in this landscape (wheat, barley, potatoes, rape, maize) which occupy watersheds and slopes with arable chernozems contaminated at a level 460-670 Bq/kg (170-220 kBq/m²) and natural grassland ecosystems which occupy lower parts of slopes and flood plains with dry and wet meadows contaminated at a level 620-710 Bq/kg (210-250 kBq/m²) were examined. Total accumulation of ¹³⁷Cs in vegetation strongly depends on the level of soil radioactive contamination (correlation coefficient 0.87). So specific ¹³⁷Cs activity in vegetation of meadows (103-160 Bq/kg) in general more than one in agricultural crops (9-92 Bq/kg). Other reason may be the predominance of perennial herbs in natural meadows whereas agricultural systems contain annual crops. The values of ¹³⁷Cs TF in the studied ecosystems vary within a relatively narrow range: from 0.01 (rape) to 0.20 (wet meadow), that confirms the discrimination of

Ground-state densities from the Rayleigh-Ritz variation principle and from density-functional theory.

Science.gov (United States)

Kvaal, Simen; Helgaker, Trygve

2015-11-14

The relationship between the densities of ground-state wave functions (i.e., the minimizers of the Rayleigh-Ritz variation principle) and the ground-state densities in density-functional theory (i.e., the minimizers of the Hohenberg-Kohn variation principle) is studied within the framework of convex conjugation, in a generic setting covering molecular systems, solid-state systems, and more. Having introduced admissible density functionals as functionals that produce the exact ground-state energy for a given external potential by minimizing over densities in the Hohenberg-Kohn variation principle, necessary and sufficient conditions on such functionals are established to ensure that the Rayleigh-Ritz ground-state densities and the Hohenberg-Kohn ground-state densities are identical. We apply the results to molecular systems in the Born-Oppenheimer approximation. For any given potential v ∈ L(3/2)(ℝ(3)) + L(∞)(ℝ(3)), we establish a one-to-one correspondence between the mixed ground-state densities of the Rayleigh-Ritz variation principle and the mixed ground-state densities of the Hohenberg-Kohn variation principle when the Lieb density-matrix constrained-search universal density functional is taken as the admissible functional. A similar one-to-one correspondence is established between the pure ground-state densities of the Rayleigh-Ritz variation principle and the pure ground-state densities obtained using the Hohenberg-Kohn variation principle with the Levy-Lieb pure-state constrained-search functional. In other words, all physical ground-state densities (pure or mixed) are recovered with these functionals and no false densities (i.e., minimizing densities that are not physical) exist. The importance of topology (i.e., choice of Banach space of densities and potentials) is emphasized and illustrated. The relevance of these results for current-density-functional theory is examined.

Quantifying the pedo-ecohydrological structure and function of degraded, grassland ecosystems

Science.gov (United States)

Brazier, Richard E.

2015-04-01

Grassland ecosystems cover significant areas of the terrestrial land mass, across a range of geoclimates, from arctic tundra, through temperate and semi-arid landscapes. In very few locations, such grasslands may be termed 'pristine' in that they remain undamaged by human activities and resilient to changing climates. In far more cases, grasslands are being degraded, often irreversibly so, with significant implications for a number of ecosystem services related to water resources, soil quality, nutrient cycles, and therefore both global food and water security. This paper draws upon empirical research that has been undertaken over the last decade to characterise a range of different grasslands in terms of soil properties, vegetation structure and geomorphology and to understand how these structures or patterns might interact or control how the grassland ecosystems function. Particular emphasis is placed upon quantifying fluxes of water, within and from grasslands, but also fluxes of sediment, via the processes of soil erosion and finally fluxes of the macronutrients Nitrogen, Phosphorus and Carbon from the landscape to surface waters. Data are presented from semi-arid grasslands, which are subject to severe encroachment by woody species, temperate upland grasslands that have been 'improved' via drainage to support grazing, temperate lowland grasslands, that are unimproved (Culm or Rhôs pastures) and finally intensively managed grasslands in temperate regions, that have been significantly modified via land management practices to improve productivity. It is hypothesised that, once degraded, the structure and function of these very diverse grassland ecosystems follows the same negative trajectory, resulting in depleted soil depths, nutrient storage capacities and therefore reduced plant growth and long-term carbon sequestration. Results demonstrate that similar, but highly complex and non-linear responses to perturbation of the ecosystem are observed, regardless of

Linking Soil Microbial Ecology to Ecosystem Functioning in Integrated Crop-Livestock Systems

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Enhanced soil stability, nutrient cycling and C sequestration potential are important ecosystem functions driven by soil microbial processes and are directly influenced by agricultural management. Integrated crop-livestock agroecosystems (ICL) can enhance these functions via high-residue returning c...

Partitioning CO₂ fluxes with isotopologue measurements and modeling to understand mechanisms of forest carbon sequestration

Energy Technology Data Exchange (ETDEWEB)

Saleska, Scott [Univ. of Arizona, Tucson, AZ (United States). Dept. of Ecology and Evolutionary Biology; Davidson, Eric [Woods Hole Research Center, Falmouth, MA (United States); Finzi, Adrien [Boston Univ., MA (United States). Dept. of Biology; Wehr, Richard [Univ. of Arizona, Tucson, AZ (United States); Moorcroft, Paul [Harvard Univ., Cambridge, MA (United States). Dept. of Organismic and Evolutionary Biology

2016-01-28

This project combines automated in situ observations of the isotopologues of CO₂ with root observations, novel experimental manipulations of below ground processes, and isotope-enabled ecosystem modeling to investigate mechanisms of below- vs. above ground carbon sequestration at the Harvard Forest Environmental Measurements Site (EMS). The proposed objectives, which have now been largely accomplished, include: (A) Partitioning of net ecosystem CO2 exchange (NEE) into photosynthesis and respiration using long-term continuous observations of the isotopic composition of NEE, and analysis of their dynamics; (B) Investigation of the influence of vegetation phenology on the timing and magnitude of carbon allocated below ground using measurements of root growth and indices of below ground autotrophic vs. heterotrophic respiration (via trenched plots andisotope measurements); (C) Testing whether plant allocation of carbon below ground stimulates the microbial decomposition of soil organic matter, using in situ rhizosphere simulation experiments wherein realistic quantities of artificial isotopically-labeled exudates are released into the soil; and (D) Synthesis and interpretation of the above data using the Ecosystem Demography Model 2 (ED2).

Mapping Ecosystem Services

OpenAIRE

Georgiev,Teodor; Burkhard,Benjamin; Maes,Joachim

2017-01-01

Ecosystem services are the contributions of ecosystem structure and function (in combination with other inputs) to human well-being. That means, humankind is strongly dependent on well-functioning ecosystems and natural capital that are the base for a constant flow of ecosystem services from nature to society. Therefore ecosystem services have the potential to become a major tool for policy and decision making on global, national, regional and local scales. Possible applications are manifold:...

Understanding the value of plant diversity for ecosystem functioning through niche theory

Science.gov (United States)

Isbell, Forest; Purves, Drew W.; Loreau, Michel

2016-01-01

Biodiversity experiments have generated robust empirical results supporting the hypothesis that ecosystems function better when they contain more species. Given that ecosystems provide services that are valued by humans, this inevitably suggests that the loss of species from natural ecosystems could diminish their value. This raises two important questions. First, will experimental results translate into the real world, where species are being lost at an alarming rate? And second, what are the benefits and pitfalls of such valuation exercises? We argue that the empirical results obtained in experiments are entirely consistent with well-established theories of species coexistence. We then examine the current body of work through the lens of niche theory and highlight where closer links with theory could open up opportunities for future research. We argue that niche theory predicts that diversity–functioning relationships are likely to be stronger (and require more species) in the field than in simplified experimental settings. However, we caution that while many of the biological processes that promote coexistence can also generate diversity–function relationships, there is no simple mapping between the two. This implies that valuation exercises need to proceed with care. PMID:27928043

Linking hydrology, ecosystem function, and livelihood sustainability in African papyrus wetlands using a Bayesian Network Model

Science.gov (United States)

van Dam, A.; Gettel, G. M.; Kipkemboi, J.; Rahman, M. M.

2011-12-01

Papyrus wetlands in East Africa provide ecosystem services supporting the livelihoods of millions but are rapidly degrading due to economic development. For ecosystem conservation, an integrated understanding of the natural and social processes driving ecosystem change is needed. This research focuses on integrating the causal relationships between hydrology, ecosystem function, and livelihood sustainability in Nyando wetland, western Kenya. Livelihood sustainability is based on ecosystem services that include plant and animal harvest for building material and food, conversion of wetlands to crop and grazing land, water supply, and water quality regulation. Specific objectives were: to integrate studies of hydrology, ecology, and livelihood activities using a Bayesian Network (BN) model and include stakeholder involvement in model development. The BN model (Netica 4.16) had 35 nodes with seven decision nodes describing demography, economy, papyrus market, and rainfall, and two target nodes describing ecosystem function (defined by groundwater recharge, nutrient and sediment retention, and biodiversity) and livelihood sustainability (drinking water supply, crop production, livestock production, and papyrus yield). The conditional probability tables were populated using results of ecohydrological and socio-economic field work and consultations with stakeholders. The model was evaluated for an average year with decision node probabilities set according to data from research, expert opinion, and stakeholders' views. Then, scenarios for dry and wet seasons and for economic development (low population growth and unemployment) and policy development (more awareness of wetland value) were evaluated. In an average year, the probability for maintaining a "good" level of sediment and nutrient retention functions, groundwater recharge, and biodiversity was about 60%. ("Good" is defined by expert opinion based on ongoing field research.) In the dry season, the probability was

Using the CARDAMOM framework to retrieve global terrestrial ecosystem functioning properties

Science.gov (United States)

Exbrayat, Jean-François; Bloom, A. Anthony; Smallman, T. Luke; van der Velde, Ivar R.; Feng, Liang; Williams, Mathew

2016-04-01

Terrestrial ecosystems act as a sink for anthropogenic emissions of fossil-fuel and thereby partially offset the ongoing global warming. However, recent model benchmarking and intercomparison studies have highlighted the non-trivial uncertainties that exist in our understanding of key ecosystem properties like plant carbon allocation and residence times. It leads to worrisome differences in terrestrial carbon stocks simulated by Earth system models, and their evolution in a warming future. In this presentation we attempt to provide global insights on these properties by merging an ecosystem model with remotely-sensed global observations of leaf area and biomass through a data-assimilation system: the CARbon Data MOdel fraMework (CARDAMOM). CARDAMOM relies on a Markov Chain Monte Carlo algorithm to retrieve confidence intervals of model parameters that regulate ecosystem properties independently of any prior land-cover information. The MCMC method thereby enables an explicit representation of the uncertainty in land-atmosphere fluxes and the evolution of terrestrial carbon stocks through time. Global experiments are performed for the first decade of the 21st century using a 1°×1° spatial resolution. Relationships emerge globally between key ecosystem properties. For example, our analyses indicate that leaf lifespan and leaf mass per area are highly correlated. Furthermore, there exists a latitudinal gradient in allocation patterns: high latitude ecosystems allocate more carbon to photosynthetic carbon (leaves) while plants invest more carbon in their structural parts (wood and root) in the wet tropics. Overall, the spatial distribution of these ecosystem properties does not correspond to usual land-cover maps and are also partially correlated with disturbance regimes. For example, fire-prone ecosystems present statistically significant higher values of carbon use efficiency than less disturbed ecosystems experiencing similar climatic conditions. These results

Transforming Ecosystems: When, Where, and How to Restore Contaminated Sites

Science.gov (United States)

Rohr, Jason R; Farag, Aïda M; Cadotte, Marc W; Clements, William H; Smith, James R; Ulrich, Cheryl P; Woods, Richard

2016-01-01

Chemical contamination has impaired ecosystems, reducing biodiversity and the provisioning of functions and services. This has spurred a movement to restore contaminated ecosystems and develop and implement national and international regulations that require it. Nevertheless, ecological restoration remains a young and rapidly growing discipline and its intersection with toxicology is even more nascent and underdeveloped. Consequently, we provide guidance to scientists and practitioners on when, where, and how to restore contaminated ecosystems. Although restoration has many benefits, it also can be expensive, and in many cases systems can recover without human intervention. Hence, the first question we address is: “When should we restore contaminated ecosystems?” Second, we provide suggestions on what to restore—biodiversity, functions, services, all 3, or something else—and where to restore given expected changes to habitats driven by global climate change. Finally, we provide guidance on how to restore contaminated ecosystems. To do this, we analyze critical aspects of the literature dealing with the ecology of restoring contaminated ecosystems. Additionally, we review approaches for translating the science of restoration to on-the-ground actions, which includes discussions of market incentives and the finances of restoration, stakeholder outreach and governance models for ecosystem restoration, and working with contractors to implement restoration plans. By explicitly considering the mechanisms and strategies that maximize the success of the restoration of contaminated sites, we hope that our synthesis serves to increase and improve collaborations between restoration ecologists and ecotoxicologists and set a roadmap for the restoration of contaminated ecosystems. PMID:26033665

Artificial Light at Night Affects Organism Flux across Ecosystem Boundaries and Drives Community Structure in the Recipient Ecosystem

Directory of Open Access Journals (Sweden)

Alessandro Manfrin

2017-10-01

Full Text Available Artificial light at night (ALAN is a widespread alteration of the natural environment that can affect the functioning of ecosystems. ALAN can change the movement patterns of freshwater animals that move into the adjacent riparian and terrestrial ecosystems, but the implications for local riparian consumers that rely on these subsidies are still unexplored. We conducted a 2-year field experiment to quantify changes of freshwater-terrestrial linkages by installing streetlights in a previously light-naïve riparian area adjacent to an agricultural drainage ditch. We compared the abundance and community composition of emerging aquatic insects, flying insects, and ground-dwelling arthropods with an unlit control site. Comparisons were made within and between years using two-way generalized least squares (GLS model and a BACI design (Before-After Control-Impact. Aquatic insect emergence, the proportion of flying insects that were aquatic in origin, and the total abundance of flying insects all increased in the ALAN-illuminated area. The abundance of several night-active ground-dwelling predators (Pachygnatha clercki, Trochosa sp., Opiliones increased under ALAN and their activity was extended into the day. Conversely, the abundance of nocturnal ground beetles (Carabidae decreased under ALAN. The changes in composition of riparian predator and scavenger communities suggest that the increase in aquatic-to-terrestrial subsidy flux may cascade through the riparian food web. The work is among the first studies to experimentally manipulate ALAN using a large-scale field experiment, and provides evidence that ALAN can affect processes that link adjacent ecosystems. Given the large number of streetlights that are installed along shorelines of freshwater bodies throughout the globe, the effects could be widespread and represent an underestimated source of impairment for both aquatic and riparian systems.

Ground-based grasslands data to support remote sensing and ecosystem modeling of terrestrial primary production

Science.gov (United States)

Olson, R. J.; Scurlock, J. M. O.; Turner, R. S.; Jennings, S. V.

1995-01-01

Estimating terrestrial net primary production (NPP) using remote-sensing tools and ecosystem models requires adequate ground-based measurements for calibration, parameterization, and validation. These data needs were strongly endorsed at a recent meeting of ecosystem modelers organized by the International Geosphere-Biosphere Program's (IGBP's) Data and Information System (DIS) and its Global Analysis, Interpretation, and Modelling (GAIM) Task Force. To meet these needs, a multinational, multiagency project is being coordinated by the IGBP DIS to compile existing NPP data from field sites and to regionalize NPP point estimates to various-sized grid cells. Progress at Oak Ridge National Laboratory (ORNL) on compiling NPP data for grasslands as part of the IGBP DIS data initiative is described. Site data and associated documentation from diverse field studies are being acquired for selected grasslands and are being reviewed for completeness, consistency, and adequacy of documentation, including a description of sampling methods. Data are being compiled in a database with spatial, temporal, and thematic characteristics relevant to remote sensing and global modeling. NPP data are available from the ORNL Distributed Active Archive Center (DAAC) for biogeochemical dynamics. The ORNL DAAC is part of the Earth Observing System Data and Information System, of the US National Aeronautics and Space Administration.

Ground-based grasslands data to support remote sensing and ecosystem modeling of terrestrial primary production

Energy Technology Data Exchange (ETDEWEB)

Olson, R.J.; Turner, R.S. [Oak Ridge National Lab., TN (United States); Scurlock, J.M.O. [King`s College London, (England); Jennings, S.V. [Tennessee Univ., Knoxville, TN (United States)

1995-12-31

Estimating terrestrial net primary production (NPP) using remote- sensing tools and ecosystem models requires adequate ground-based measurements for calibration, parameterization, and validation. These data needs were strongly endorsed at a recent meeting of ecosystem modelers organized by the International Geosphere-Biosphere Programme`s (IGBP`s) Data and Information System (DIS) and its Global Analysis, Interpretation, and Modelling (GAIM) Task Force. To meet these needs, a multinational, multiagency project is being coordinated by the IGBP DIS to compile existing NPP data from field sites and to regionalize NPP point estimates to various-sized grid cells. Progress at Oak Ridge National Laboratory (ORNL) on compiling NPP data for grasslands as part of the IGBP DIS data initiative is described. Site data and associated documentation from diverse field studies are being acquired for selected grasslands and are being reviewed for completeness, consistency, and adequacy of documentation, including a description of sampling methods. Data are being compiled in a database with spatial, temporal, and thematic characteristics relevant to remote sensing and global modeling. NPP data are available from the ORNL Distributed Active Archive Center (DAAC) for biogeochemical dynamics. The ORNL DAAC is part of the Earth Observing System Data and Information System, of the US National Aeronautics and Space Administration.

Ab initio calculation atomics ground state wave function for interactions Ion- Atom

International Nuclear Information System (INIS)

Shojaee, F.; Bolori zadeh, M. A.

2007-01-01

Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.

Exponential Decline of Deep-Sea Ecosystem Functioning Linked to Benthic Biodiversity Loss

OpenAIRE

Danovaro, Roberto; Gambi, Cristina; Dell'Anno, Antonio; Corinaldesi, Cinzia; Fraschetti, Simonetta; Vanreusel, Ann; Vincx, Magda; Gooday, Andrew J.

2008-01-01

BackgroundRecent investigations suggest that biodiversity loss might impair the functioning and sustainability of ecosystems. Although deep-sea ecosystems are the most extensive on Earth, represent the largest reservoir of biomass, and host a large proportion of undiscovered biodiversity, the data needed to evaluate the consequences of biodiversity loss on the ocean floor are completely lacking.ResultsHere, we present a global-scale study based on 116 deep-sea sites that relates benthic biodi...

Topographic Controls on Southern California Ecosystem Function and Post-fire Recovery: a Satellite and Near-surface Remote Sensing Approach

Science.gov (United States)

Azzari, George

Southern Californian wildfires can influence climate in a variety of ways, including changes in surface albedo, emission of greenhouse gases and aerosols, and the production of tropospheric ozone. Ecosystem post-fire recovery plays a key role in determining the strength, duration, and relative importance of these climate forcing agents. Southern California's ecosystems vary markedly with topography, creating sharp transitions with elevation, aspect, and slope. Little is known about the ways topography influences ecosystem properties and function, particularly in the context of post-fire recovery. We combined images from the USGS satellite Landsat 5 with flux tower measurements to analyze pre- and post-fire albedo and carbon exchanged by Southern California's ecosystems in the Santa Ana Mountains. We reduced the sources of external variability in Landsat images using several correction methods for topographic and bidirectional effects. We used time series of corrected images to infer the Net Ecosystem Exchange and surface albedo, and calculated the radiative forcing due to CO2 emissions and albedo changes. We analyzed the patterns of recovery and radiative forcing on north- and south-facing slopes, stratified by vegetation classes including grassland, coastal sage scrub, chaparral, and evergreen oak forest. We found that topography strongly influenced post-fire recovery and radiative forcing. Field observations are often limited by the difficulty of collecting ground validation data. Current instrumentation networks do not provide adequate spatial resolution for landscape-level analysis. The deployment of consumer-market technology could reduce the cost of near-surface measurements, allowing the installation of finer-scale instrument networks. We tested the performance of the Microsoft Kinect sensor for measuring vegetation structure. We used Kinect to acquire 3D vegetation point clouds in the field, and used these data to compute plant height, crown diameter, and

Using landscape limnology to classify freshwater ecosystems for multi-ecosystem management and conservation

Science.gov (United States)

Soranno, Patricia A.; Cheruvelil, Kendra Spence; Webster, Katherine E.; Bremigan, Mary T.; Wagner, Tyler; Stow, Craig A.

2010-01-01

Governmental entities are responsible for managing and conserving large numbers of lake, river, and wetland ecosystems that can be addressed only rarely on a case-by-case basis. We present a system for predictive classification modeling, grounded in the theoretical foundation of landscape limnology, that creates a tractable number of ecosystem classes to which management actions may be tailored. We demonstrate our system by applying two types of predictive classification modeling approaches to develop nutrient criteria for eutrophication management in 1998 north temperate lakes. Our predictive classification system promotes the effective management of multiple ecosystems across broad geographic scales by explicitly connecting management and conservation goals to the classification modeling approach, considering multiple spatial scales as drivers of ecosystem dynamics, and acknowledging the hierarchical structure of freshwater ecosystems. Such a system is critical for adaptive management of complex mosaics of freshwater ecosystems and for balancing competing needs for ecosystem services in a changing world.

Modelling global nitrogen export to ground and surface water from natural ecosystems: impact of N deposition, climate, and CO2 concentration

Science.gov (United States)

Braakhekke, Maarten; Rebel, Karin; Dekker, Stefan; van Beek, Rens; Bierkens, Marc; Smith, Ben; Wassen, Martin

2015-04-01

For large regions in the world strong increases in atmospheric nitrogen (N) deposition are predicted as a result of emissions from fossil fuel combustion and food production. This will cause many previously N limited ecosystems to become N saturated, leading to increased export to ground and surface water and negative impacts on the environment and human health. However, precise N export fluxes are difficult to predict. Due to its strong link to carbon, N in vegetation and soil is also determined by productivity, as affected by rising atmospheric CO2 concentration and temperature, and denitrification. Furthermore, the N concentration of water delivered to streams depends strongly on local hydrological conditions. We aim to study how N delivery to ground and surface water is affected by changes in environmental factors. To this end we are developing a global dynamic modelling system that integrates representations of N cycling in vegetation and soil, and N delivery to ground and surface water. This will be achieved by coupling the dynamic global vegetation model LPJ-GUESS, which includes representations of N cycling, as well as croplands and pasture, to the global water balance model PCR-GLOBWB, which simulates surface runoff, interflow, groundwater recharge, and baseflow. This coupling will allow us to trace N across different systems and estimate the input of N into the riverine system which can be used as input for river biogeochemical models. We will present large scale estimates of N leaching and transport to ground and surface water for natural ecosystems in different biomes, based on a loose coupling of the two models. Furthermore, by means of a factorial model experiment we will explore how these fluxes are influenced by N deposition, temperature, and CO2 concentration.

Taking a closer look: disentangling effects of functional diversity on ecosystem functions with a trait-based model across hierarchy and time.

Science.gov (United States)

Holzwarth, Frédéric; Rüger, Nadja; Wirth, Christian

2015-03-01

Biodiversity and ecosystem functioning (BEF) research has progressed from the detection of relationships to elucidating their drivers and underlying mechanisms. In this context, replacing taxonomic predictors by trait-based measures of functional composition (FC)-bridging functions of species and of ecosystems-is a widely used approach. The inherent challenge of trait-based approaches is the multi-faceted, dynamic and hierarchical nature of trait influence: (i) traits may act via different facets of their distribution in a community, (ii) their influence may change over time and (iii) traits may influence processes at different levels of the natural hierarchy of organization. Here, we made use of the forest ecosystem model 'LPJ-GUESS' parametrized with empirical trait data, which creates output of individual performance, community assembly, stand-level states and processes. To address the three challenges, we resolved the dynamics of the top-level ecosystem function 'annual biomass change' hierarchically into its various component processes (growth, leaf and root turnover, recruitment and mortality) and states (stand structures, water stress) and traced the influence of different facets of FC along this hierarchy in a path analysis. We found an independent influence of functional richness, dissimilarity and identity on ecosystem states and processes and hence biomass change. Biodiversity effects were only positive during early succession and later turned negative. Unexpectedly, resource acquisition (growth, recruitment) and conservation (mortality, turnover) played an equally important role throughout the succession. These results add to a mechanistic understanding of biodiversity effects and place a caveat on simplistic approaches omitting hierarchical levels when analysing BEF relationships. They support the view that BEF relationships experience dramatic shifts over successional time that should be acknowledged in mechanistic theories.

Ecosystem Services and Potential Utilization of of Urban Typha angustifolia Wetlands of across Metropolitan Bangkok, Thailand

Science.gov (United States)

Sritrairat, S.

2014-12-01

Over half the world's 7.2 billion population are living in urban habitats. While these cities only occupy 2% of the world's surface, the ecological footprint by these cities combined is far greater than that of the other 98% of the world. Bangkok, Thailand has experienced this rapid urbanization that has resulted in various environmental problems, including pollution, land subsidence, and flooding. Major flooding in 2011 has raised awareness about the importance of restoring ecosystem services in urban space to cope up with the forecasted extreme climatic conditions. Finding localized flooding, carbon and pollution mitigation methods will be important to cities. Upland reforestration has been proposed as a way to decrease these anthropogenic and climate change impacts. However, there is also a large area of wetlands in Bangkok with possibly high ecosystem services that have not been quantified. This study measure above ground and below ground carbon accumulation in wide-spread Typha angustifolia wetlands as an untapped source of ecosystem services that are worth projected. These wetlands are typically viewed as wasteland and are not being protected. We examined carbon and heavy metals (Pb, Zn, Cu) pools in 7 wetlands across Bangkok with various environmental settings--from industrialized zone, to residential area, farms, and protected urban green space. The results indicate recent peat accumulation layer by these wetlands at high rate. Heavy concentration are found near contaminant source such as industries and farms. Combined with their ability to buffer storms and being habitats for wildlife, these wetlands have important values in increasing ecosystem services in urban space and should be considered for protection.

The role of ants, birds and bats for ecosystem functions and yield in oil palm plantations.

Science.gov (United States)

Denmead, Lisa H; Darras, Kevin; Clough, Yann; Diaz, Patrick; Grass, Ingo; Hoffmann, Munir P; Nurdiansyah, Fuad; Fardiansah, Rico; Tscharntke, Teja

2017-07-01

One of the world's most important and rapidly expanding crops, oil palm, is associated with low levels of biodiversity. Changes in predator communities might alter ecosystem services and subsequently sustainable management but these links have received little attention to date. Here, for the first time, we manipulated ant and flying vertebrate (birds and bats) access to oil palms in six smallholder plantations in Sumatra (Indonesia) and measured effects on arthropod communities, related ecosystem functions (herbivory, predation, decomposition and pollination) and crop yield. Arthropod predators increased in response to reductions in ant and bird access, but the overall effect of experimental manipulations on ecosystem functions was minimal. Similarly, effects on yield were not significant. We conclude that ecosystem functions and productivity in oil palm are, under current levels of low pest pressure and large pollinator populations, robust to large reductions of major predators. © 2017 by the Ecological Society of America.

Predicting richness effects on ecosystem function in natural communities

DEFF Research Database (Denmark)

Dangles, Olivier; Crespo-Pérez, Verónica; Andino, Patricio

2011-01-01

rates in the field, although water discharge may also play a role locally. We also examined the relative contribution of the three most abundant shredders on decomposition rates by manipulating shredder richness and community composition in a field experiment. Transgressive overyielding was detected....... Despite the increased complexity of experimental and theoretical studies on the biodiversity-ecosystem functioning (B-EF) relationship, a major challenge is to demonstrate whether the observed importance of biodiversity in controlled experimental systems also persists in nature. Due...... to their structural simplicity and their low levels of human impacts, extreme species-poor ecosystems may provide new insights into B-EF relationships in natural systems. We address this issue using shredder invertebrate communities and organic matter decomposition rates in 24 high-altitude (3200-3900 m) Neotropical...

Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

Science.gov (United States)

Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

2015-01-01

Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

Directory of Open Access Journals (Sweden)

Pablo Rodríguez-Lozano

Full Text Available Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1 leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2 triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel, conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

Responses of plant community composition and biomass production to warming and nitrogen deposition in a temperate meadow ecosystem.

Science.gov (United States)

Zhang, Tao; Guo, Rui; Gao, Song; Guo, Jixun; Sun, Wei

2015-01-01

Climate change has profound influences on plant community composition and ecosystem functions. However, its effects on plant community composition and biomass production are not well understood. A four-year field experiment was conducted to examine the effects of warming, nitrogen (N) addition, and their interactions on plant community composition and biomass production in a temperate meadow ecosystem in northeast China. Experimental warming had no significant effect on plant species richness, evenness, and diversity, while N addition highly reduced the species richness and diversity. Warming tended to reduce the importance value of graminoid species but increased the value of forbs, while N addition had the opposite effect. Warming tended to increase the belowground biomass, but had an opposite tendency to decrease the aboveground biomass. The influences of warming on aboveground production were dependent upon precipitation. Experimental warming had little effect on aboveground biomass in the years with higher precipitation, but significantly suppressed aboveground biomass in dry years. Our results suggest that warming had indirect effects on plant production via its effect on the water availability. Nitrogen addition significantly increased above- and below-ground production, suggesting that N is one of the most important limiting factors determining plant productivity in the studied meadow steppe. Significant interactive effects of warming plus N addition on belowground biomass were also detected. Our observations revealed that environmental changes (warming and N deposition) play significant roles in regulating plant community composition and biomass production in temperate meadow steppe ecosystem in northeast China.

Land use intensification alters ecosystem multifunctionality via loss of biodiversity and changes to functional composition

OpenAIRE

Allan, Eric; Manning, Pete; et al

2015-01-01

Global change, especially land-use intensification, affects human well-being by impacting the deliv-ery of multiple ecosystem services (multifunctionality). However, whether biodiversity loss is amajor component of global change effects on multifunctionality in real-world ecosystems, as inexperimental ones, remains unclear. Therefore, we assessed biodiversity, functional compositionand 14 ecosystem services on 150 agricultural grasslands differing in land-use intensity. We alsointroduce five mu...

Land use intensification alters ecosystem multifunctionality via loss of biodiversity and changes to functional composition.

OpenAIRE

Allan Eric; Manning Pete; Alt Fabian; Binkenstein Julia; Blaser Stefan; Blüthgen Nico; Böhm Stefan; Grassein Fabrice; Hölzel Norbert; Klaus Valentin H.; Kleinebecker Till; Morrys Elisabeth Kathryn; Oelmann Yvonne; Prati Daniel; Renner Sven C.

2015-01-01

Abstract Global change, especially land?use intensification, affects human well?being by impacting the delivery of multiple ecosystem services (multifunctionality). However, whether biodiversity loss is a major component of global change effects on multifunctionality in real?world ecosystems, as in experimental ones, remains unclear. Therefore, we assessed biodiversity, functional composition and 14 ecosystem services on 150 agricultural grasslands differing in land?use intensity. We also int...

Dryland ecosystem responses to precipitation extremes and wildfire at a long-term rainfall manipulation experiment

Science.gov (United States)

Brown, R. F.; Collins, S. L.

2017-12-01

Climate is becoming increasingly more variable due to global environmental change, which is evidenced by fewer, but more extreme precipitation events, changes in precipitation seasonality, and longer, higher severity droughts. These changes, combined with a rising incidence of wildfire, have the potential to strongly impact net primary production (NPP) and key biogeochemical cycles, particularly in dryland ecosystems where NPP is sequentially limited by water and nutrient availability. Here we utilize a ten-year dataset from an ongoing long-term field experiment established in 2007 in which we experimentally altered monsoon rainfall variability to examine how our manipulations, along with naturally occurring events, affect NPP and associated biogeochemical cycles in a semi-arid grassland in central New Mexico, USA. Using long-term regional averages, we identified extremely wet monsoon years (242.8 mm, 2013), and extremely dry monsoon years (86.0 mm, 2011; 80.0 mm, 2015) and water years (117.0 mm, 2011). We examined how changes in precipitation variability and extreme events affected ecosystem processes and function particularly in the context of ecosystem recovery following a 2009 wildfire. Response variables included above- and below-ground plant biomass (ANPP & BNPP) and abundance, soil nitrogen availability, and soil CO2 efflux. Mean ANPP ranged from 3.6 g m-2 in 2011 to 254.5 g m-2 in 2013, while BNPP ranged from 23.5 g m-2 in 2015 to 194.2 g m-2 in 2013, demonstrating NPP in our semi-arid grassland is directly linked to extremes in both seasonal and annual precipitation. We also show increased nitrogen deposition positively affects NPP in unburned grassland, but has no significant impact on NPP post-fire except during extremely wet monsoon years. While soil respiration rates reflect lower ANPP post-fire, patterns in CO2 efflux have not been shown to change significantly in that efflux is greatest following large precipitation events preceded by longer drying

Ground-state properties of third-row elements with nonlocal density functionals

International Nuclear Information System (INIS)

Bagno, P.; Jepsen, O.; Gunnarsson, O.

1989-01-01

The cohesive energy, the lattice parameter, and the bulk modulus of third-row elements are calculated using the Langreth-Mehl-Hu (LMH), the Perdew-Wang (PW), and the gradient expansion functionals. The PW functional is found to give somewhat better results than the LMH functional and both are found to typically remove half the errors in the local-spin-density (LSD) approximation, while the gradient expansion gives worse results than the local-density approximation. For Fe both the LMH and PW functionals correctly predict a ferromagnetic bcc ground state, while the LSD approximation and the gradient expansion predict a nonmagnetic fcc ground state

Forest ecosystems functioning of and conducting of forestry in the zones of absolute alienation

International Nuclear Information System (INIS)

Yirklyienko, S.P.; Buzun, V.O.; Dmitrenko, O.G.; Turchak, F.M.

2001-01-01

The main regularities of forest ecosystems functioning in the zone of absolute alienation were shown. The radio contamination mozaicity of forest ecosystems was underlined. Regularities of 137 Cs accumulation in the wood of the main arboreous species were analyzed. The detailed measures of forestry conducting and forests rehabilitation were proposed

Relative effects of precipitation variability and warming on tallgrass prairie ecosystem function

Directory of Open Access Journals (Sweden)

P. A. Fay

2011-10-01

Full Text Available Precipitation and temperature drive many aspects of terrestrial ecosystem function. Climate change scenarios predict increasing precipitation variability and temperature, and long term experiments are required to evaluate the ecosystem consequences of interannual climate variation, increased growing season (intra-annual rainfall variability, and warming. We present results from an experiment applying increased growing season rainfall variability and year round warming in native tallgrass prairie. During ten years of study, total growing season rainfall varied 2-fold, and we found ~50–200% interannual variability in plant growth and aboveground net primary productivity (ANPP, leaf carbon assimilation (A_CO2, and soil CO₂ efflux (J_CO2 despite only ~40% variation in mean volumetric soil water content (0–15 cm, Θ₁₅. Interannual variation in soil moisture was thus amplified in most measures of ecosystem response. Differences between years in Θ₁₅ explained the greatest portion (14–52% of the variation in these processes. Experimentally increased intra-annual season rainfall variability doubled the amplitude of intra-annual soil moisture variation and reduced Θ₁₅ by 15%, causing most ecosystem processes to decrease 8–40% in some or all years with increased rainfall variability compared to ambient rainfall timing, suggesting reduced ecosystem rainfall use efficiency. Warming treatments increased soil temperature at 5 cm depth, particularly during spring, fall, and winter. Warming advanced canopy green up in spring, increased winter J_CO2, and reduced summer J_CO2 and forb ANPP, suggesting that the effects of warming differed in cooler versus warmer parts of the year. We conclude that (1 major ecosystem processes in this grassland may be substantially altered by predicted changes in

Finding common ground for biodiversity and ecosystem services

CSIR Research Space (South Africa)

Reyers, B

2012-05-01

Full Text Available Recently, some members of the conservation community have used ecosystem services as a strategy to conserve biodiversity. Others in the community have criticized this strategy as a distraction from the mission of biodiversity conservation...

Diversity and abundance of dung beetles (Coleoptera: Scaraebidae) at several different ecosystem functions in Peninsular Malaysia

Science.gov (United States)

Din, Abdullah Muhaimin Mohammad; Yaakop, Salmah; Hazmi, Izfa Riza

2015-09-01

Dung beetles has known for its bioindicator characteristic. Sensitive towards forest disturbance, dung beetles population and diversity will be less in disturbed and modified area. The objective of this study is to evaluate the diversity and distribution of dung beetles in different type of ecosystems in Peninsular Malaysia. Fifteen baited pitfall traps aligned in three transects were used in this study. Samples were collected after 24 h and repeated three time collections and identified afterwards. Two ecosystem types were selected, which are forested and agricultural ecosystem (livestock and plantation). A total of 4249 individuals, 47 species, in 11 genera was successfully collected from all localities. The H' index for Fraser Hill, Langkawi, Bangi Reserve Forest, Selangor (HSB), Sungkai Reserve Forest, Perak (SRF), Chini Lake, Bera Lake, chicken farm, goat farm, Longan plantation, and palm oil plantation were 1.58, 1.74, 2.17, 2.63, 1.80, 1.52, 1.63, 0.46, 0.00 and 1.98 respectively.Forest ecosystem, SRF shows the highest abundance (1486 individuals) and diversity, while for agricultural ecosystem,palm oil plantation shows the highest with 273 individuals and 16 species. Based onDetrended Correspondence Analysis (DCA) shows two groups that separate forest ecosystem with the agricultural ecosystem, with palm oil is the nearest to the forest. Palm oil ecosystem can sustain a dung beetles population due to the area can provide the requirements for the dung beetles to survive, such as food which comes from local domestic cows, shade from sunlight provide by the palm oil trees, and ground cover from small plants and shrubs.Even though modified ecosystem should have lower diversity of dung beetles, but some factors must be measured as well in order to have a better point of view.

Towards an ecologically grounded functional practice in rehabilitation.

Science.gov (United States)

Vaz, Daniela Virgínia; Silva, Paula Lanna; Mancini, Marisa Cotta; Carello, Claudia; Kinsella-Shaw, Jeffrey

2017-04-01

According to the International Classification of Functioning, Disability and Health, effective rehabilitation requires interventions that go beyond minimizing pathological conditions and associated symptoms. The scope of practice must include promoting an individual's activity within relevant contexts. We argue that best practice requires decisions that are not only evidence-based but also theory-based. Perception and action theories are essential for interpreting evidence and clinical phenomena as well as for developing new interventions. It is our contention that rehabilitation goals can best be achieved if inspired by the ecological approach to perception and action, an approach that focuses on the dynamics of interacting constraints of performer, task and environment. This contrasts with organism-limited motor control theories that have important influence in clinical practice. Parallels between such theories and the medical model of care highlight their fundamental inconsistency with the current understanding of functioning. We contend that incorporating ecological principles into rehabilitation research and practice can help advance our understanding of the complexity of action and provide better grounding for the development of effective functional practice. Implications and initial suggestions for an ecologically grounded functional practice are outlined. Copyright © 2017 Elsevier B.V. All rights reserved.

Tree-Based Ecosystem Approaches (TBEAs as Multi-Functional Land Management Strategies—Evidence from Rwanda

Directory of Open Access Journals (Sweden)

Miyuki Iiyama

2018-04-01

Full Text Available Densely populated rural areas in the East African Highlands have faced significant intensification challenges under extreme population pressure on their land and ecosystems. Sustainable agricultural intensification, in the context of increasing cropping intensities, is a prerequisite for deliberate land management strategies that deliver multiple ecosystem goods (food, energy, income sources, etc. and services (especially improving soil conditions on the same land, as well as system resilience, if adopted at scale. Tree based ecosystem approaches (TBEAs are among such multi-functional land management strategies. Knowledge on the multi-functionality of TBEAs and on their scaling up, however, remains severely limited due to several methodological challenges. This study aims at offering an analytical perspective to view multi-functional TBEAs as an integral part of sustainable agricultural intensification. The study proposes a conceptual framework to guide the analysis of socio-economic data and applies it to cross-site analysis of TBEAs in extremely densely populated Rwanda. Heterogeneous TBEAs were identified across Rwanda’s different agro-ecological zones to meet locally-specific smallholders’ needs for a set of ecosystem goods and services on the same land. The sustained adoption of TBEAs would be guaranteed if farmers subjectively recognize their compatibility and synergy with sustainable intensification of existing farming systems, supported by favorable institutional conditions.

Evaluation of mangrove ecosystem service functions of Ximen Island Marine Specially Protected Areas in Yueqing Bay, China

Science.gov (United States)

Wang, D. G.; Sun, L.; Tan, Y. H.; Shi, A. Q.; Cheng, J.

2017-08-01

Taking the mangrove ecosystem of Ximen Island National Marine Specially Protected Areas as the research object, the ecological service value of the mangrove forest was evaluated and analyzed using a market value method, an ecological value method and a carbon tax method. The results showed that the ecosystem service value of the mangrove forest on Ximen Island is worth a total of 16,104,000 CNY/a. Among the value of individual ecosystem services, the direct value of material production function and leisure function reached 1,385,000 CNY/a, with a ratio of 8.6%. The indirect value of disturbance regulation, gas regulation, water purification, habitat function and culture research reached 14,719,000 CNY/a, with a ratio of 91.4%. Among the above sub-items, the proportion of disturbance regulation value, habitat function value and cultural research function value reached 78.8%, which reflects the important scientific value and ecological value of the Ximen Island mangrove ecosystem, especially its vital importance in providing a habitat for birds and playing a role in disaster prevention and mitigation.

Impacts of discarded plastic bags on marine assemblages and ecosystem functioning.

Science.gov (United States)

Green, Dannielle Senga; Boots, Bas; Blockley, David James; Rocha, Carlos; Thompson, Richard

2015-05-05

The accumulation of plastic debris is a global environmental problem due to its durability, persistence, and abundance. Although effects of plastic debris on individual marine organisms, particularly mammals and birds, have been extensively documented (e.g., entanglement and choking), very little is known about effects on assemblages and consequences for ecosystem functioning. In Europe, around 40% of the plastic items produced are utilized as single-use packaging, which rapidly accumulate in waste management facilities and as litter in the environment. A range of biodegradable plastics have been developed with the aspiration of reducing the persistence of litter; however, their impacts on marine assemblages or ecosystem functioning have never been evaluated. A field experiment was conducted to assess the impact of conventional and biodegradable plastic carrier bags as litter on benthic macro- and meio-faunal assemblages and biogeochemical processes (primary productivity, redox condition, organic matter content, and pore-water nutrients) on an intertidal shore near Dublin, Ireland. After 9 weeks, the presence of either type of bag created anoxic conditions within the sediment along with reduced primary productivity and organic matter and significantly lower abundances of infaunal invertebrates. This indicates that both conventional and biodegradable bags can rapidly alter marine assemblages and the ecosystem services they provide.

Interactive effects of climate change and biodiversity loss on ecosystem functioning.

Science.gov (United States)

Pires, Aliny P F; Srivastava, Diane S; Marino, Nicholas A C; MacDonald, A Andrew M; Figueiredo-Barros, Marcos Paulo; Farjalla, Vinicius F

2018-05-01

Climate change and biodiversity loss are expected to simultaneously affect ecosystems, however research on how each driver mediates the effect of the other has been limited in scope. The multiple stressor framework emphasizes non-additive effects, but biodiversity may also buffer the effects of climate change, and climate change may alter which mechanisms underlie biodiversity-function relationships. Here, we performed an experiment using tank bromeliad ecosystems to test the various ways that rainfall changes and litter diversity may jointly determine ecological processes. Litter diversity and rainfall changes interactively affected multiple functions, but how depends on the process measured. High litter diversity buffered the effects of altered rainfall on detritivore communities, evidence of insurance against impacts of climate change. Altered rainfall affected the mechanisms by which litter diversity influenced decomposition, reducing the importance of complementary attributes of species (complementarity effects), and resulting in an increasing dependence on the maintenance of specific species (dominance effects). Finally, altered rainfall conditions prevented litter diversity from fueling methanogenesis, because such changes in rainfall reduced microbial activity by 58%. Together, these results demonstrate that the effects of climate change and biodiversity loss on ecosystems cannot be understood in isolation and interactions between these stressors can be multifaceted. © 2018 by the Ecological Society of America.

Ecosystem development after mangrove wetland creation: plant-soil change across a 20-year chronosequence

Science.gov (United States)

Osland, Michael J.; Spivak, Amanda C.; Nestlerode, Janet A.; Lessmann, Jeannine M.; Almario, Alejandro E.; Heitmuller, Paul T.; Russell, Marc J.; Krauss, Ken W.; Alvarez, Federico; Dantin, Darrin D.; Harvey, James E.; From, Andrew S.; Cormier, Nicole; Stagg, Camille L.

2012-01-01

Mangrove wetland restoration and creation efforts are increasingly proposed as mechanisms to compensate for mangrove wetland losses. However, ecosystem development and functional equivalence in restored and created mangrove wetlands are poorly understood. We compared a 20-year chronosequence of created tidal wetland sites in Tampa Bay, Florida (USA) to natural reference mangrove wetlands. Across the chronosequence, our sites represent the succession from salt marsh to mangrove forest communities. Our results identify important soil and plant structural differences between the created and natural reference wetland sites; however, they also depict a positive developmental trajectory for the created wetland sites that reflects tightly coupled plant-soil development. Because upland soils and/or dredge spoils were used to create the new mangrove habitats, the soils at younger created sites and at lower depths (10-30 cm) had higher bulk densities, higher sand content, lower soil organic matter (SOM), lower total carbon (TC), and lower total nitrogen (TN) than did natural reference wetland soils. However, in the upper soil layer (0-10 cm), SOM, TC, and TN increased with created wetland site age simultaneously with mangrove forest growth. The rate of created wetland soil C accumulation was comparable to literature values for natural mangrove wetlands. Notably, the time to equivalence for the upper soil layer of created mangrove wetlands appears to be faster than for many other wetland ecosystem types. Collectively, our findings characterize the rate and trajectory of above- and below-ground changes associated with ecosystem development in created mangrove wetlands; this is valuable information for environmental managers planning to sustain existing mangrove wetlands or mitigate for mangrove wetland losses.

Measurement of changes in marine benthic ecosystem function following physical disturbance by dredging

OpenAIRE

Wan Hussin, Wan Mohd Rauhan

2012-01-01

Measuring the impact of physical disturbance on macrofaunal communities and sediment composition is important given the increased demand for the exploitation and disturbance of marine ecosystems. The aim of the present investigation was to provide a comprehensive study about the extent to which the disturbance (especially aggregate dredging) may affect benthic ecosystem function. The first part of the thesis concerns a field investigation of the impacts of dredging on the be...

Mycorrhizal symbioses of Salix repens : diversity and functional significance

NARCIS (Netherlands)

Heijden, van der E.W.

2000-01-01

This thesis investigates the significance of different mycorrhizal fungi, belonging to different functional types (arbuscular mycorrhiza-AM and ectomycorrhiza-EcM), in Salix repens . A comparison between above-ground and below-ground observations on ectomycorrhizal

Faunal impact on vegetation structure and ecosystem function in mangrove forests

DEFF Research Database (Denmark)

Cannicci, S.; Burrows, Damien; Fratini, Sara

2008-01-01

The last 20 years witnessed a real paradigm shift concerning the impact of biotic factors on ecosystem functions as well as on vegetation structure of mangrove forests. Before this small scientific revolution took place, structural aspects of mangrove forests were viewed to be the result of abiotic...... processes acting from the bottom-up, while, at ecosystem level, the outwelling hypothesis stated that mangroves primary production was removed via tidal action and carried to adjacent nearshore ecosystems where it fuelled detrital based food-webs. The sesarmid crabs were the first macrofaunal taxon...... to be considered a main actor in mangrove structuring processes, thanks to a number of studies carried out in the Indo-Pacific forests in the late 1970s and early 1980s. Following these classical papers, a number of studies on Sesarmidae feeding and burrowing ecology were carried out, which leave no doubts about...

Synergy of extreme drought and shrub invasion reduce ecosystem functioning and resilience in water-limited climates

Science.gov (United States)

Caldeira, Maria C.; Lecomte, Xavier; David, Teresa S.; Pinto, Joaquim G.; Bugalho, Miguel N.; Werner, Christiane

2015-10-01

Extreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme events. Using a manipulative shrub removal experiment and the co-occurrence of an extreme drought event (2011/2012) in a Mediterranean woodland, we show that native shrub invasion and extreme drought synergistically reduced ecosystem transpiration and the resilience of key-stone oak tree species. Ecosystem transpiration was dominated by the water use of the invasive shrub Cistus ladanifer, which further increased after the extreme drought event. Meanwhile, the transpiration of key-stone tree species decreased, indicating a competitive advantage in favour of the invader. Our results suggest that in Mediterranean-type climates the invasion of water spending species and projected recurrent extreme drought events may synergistically cause critical drought tolerance thresholds of key-stone tree species to be surpassed, corroborating observed higher tree mortality in the invaded ecosystems. Ultimately, this may shift seasonally water limited ecosystems into less desirable alternative states dominated by water spending invasive shrubs.

Effects of a large scale nitrogen and phosphorous fertilization on the ecosystem functioning of a Mediterranean tree-grass ecosystem

Science.gov (United States)

Migliavacca, Mirco; El Madany, Tarek; Perez-Priego, Oscar; Carrara, Arnaud; Hammer, Tiana; Henkel, Kathin; Kolle, Olaf; Luo, Yunpeng; Moreno, Gerardo; Morris, Kendalynn; Nair, Richard; Schrumpf, Marion; Wutzler, Thomas; Reichstein, Markus

2017-04-01

Recent studies have shown how human induced N/P imbalances affect essential ecosystem processes, and might be particularly important in water-limited ecosystems. In this contribution we will present results from an ecosystem scale nutrient manipulation experiment on a Mediterranean tree-grass ecosystem (Majadas del Tietar, Spain). Specifically, we will show how ecosystem functioning (e.g. light use efficiency, water use efficiency - WUE, albedo) changes as consequence of N and NP fertilization. A cluster of eddy covariance (EC) flux towers has been set up beside a long-term EC site (Control site) to measured high temporal resolution C and water fluxes between the ecosystem and the atmosphere. The sites were selected in a way to have similar pre-treatment conditions. Two out of three EC footprint areas (18 Ha) were fertilized with N and NP at the beginning of 2015 and 2016. To interpret the variations in C and water fluxes measured with the EC systems we monitored spatial and temporal variations in phenology, plant traits, species richness, and tree transpiration by using sap-flow meters, digital repeat photography, as well as soil sampling. The results show a consistent increase ( 15% compared to the Control site) in net ecosystem production (NEP) observed both in the N and the NP treatments. An increase of evapotranspiration (ET) of about 15% and 10% is observed in the N and NP site, respectively, indicating an increase of WUE in the NP treatment. The partitioning of the NEP into its gross components, the gross primary production (GPP) and the total ecosystem respiration (TER), show that the fertilization stimulated more GPP rather than TER, increasing therefore the capability of the ecosystem to act as carbon sink. The effects of fertilization are pronounced in spring and autumn and negligible in summer. This indicates that grass reacted much more than trees to N and NP addition. An increase of greenness and also an earlier green-up of grass in the N and NP sites

X-ray study of residual stress distribution of ground ceramics

International Nuclear Information System (INIS)

Sakaida, Yoshihisa; Tanaka, Keisuke; Ikuhara, Yuichi; Suzuki, Kenzi.

1997-01-01

The residual stress distribution of ground ceramics was determined from the eigen strain existing in the ground surface. The eigen strain of ground ceramics was tensile, and exponentially decreased with the distance from the surface. The residual stress distribution is given as a superposition of an exponential function of compression and a linear function. It is found that the actual residual stress distribution can be approximated by a compressive exponential function because the magnitude of tensile residual stress is negligibly small compared to the compressive residual stress. In the experiments, the diffraction angle was measured on ground silicon nitride for a wide range of sin 2 ψ using the glancing incidence X-ray diffraction technique. A strong nonlinearity was found in the 2θ-sin 2 ψ diagram at very high ψ-angles. From the analysis of nonlinearity, the residual stress distribution was determined. The residual stress distribution of silicon nitride coincided with the distribution calculated from the eigen strain distribution. Transmission electron microscopy was used to clarify the origin of generation of the residual stress. Both strain contrasts and microcracks were observed below the ground surface ; straight dislocations were also observed within silicon nitride grains near the ground surface. (author)

Aspects of the carbon cycle in terrestrial ecosystems of Northeastern Smaaland

Energy Technology Data Exchange (ETDEWEB)

Tagesson, Torbern [Lund Univ., Geobiosphere Science Centre (Sweden). Physical Geography and Ecosystems Analysis

2006-02-15

Boreal and temperate ecosystems of the northern hemisphere are important for the future development of global climate. In this study, the carbon cycle has been studied in a pine forest, a meadow, a spruce forest and two deciduous forests in the Simpevarp investigation area in southern Sweden (57 deg 5 min N, 34 deg 55 min E). Ground respiration and ground Gross Primary Production (GPP) has been measured three times during spring 2004 with the closed chamber technique. Soil temperature, soil moisture and Photosynthetically Active Radiation (PAR) were also measured. An exponential regression with ground respiration against soil temperature was used to extrapolate respiration over spring 2004. A logarithmic regression with ground GPP against PAR was used to extrapolate GPP in meadow over spring 2004. Ground respiration is affected by soil temperature in all ecosystems but pine, but still it only explains a small part of the variation in respiration and this indicates that other abiotic factors also have an influence. Soil moisture affects respiration in spruce and one of the deciduous ecosystems. A comparison between measured and extrapolated ground respiration indicated that soil temperature could be used to extrapolate ground respiration. PAR is the main factor influencing GPP in all ecosystems but pine, still it could not be used to extrapolate GPP in meadow since too few measurements were done and they were from different periods of spring. Soil moisture did not have any significant effect on GPP. A Dynamic Global Vegetation Model, a DGVM called LPJ-GUESS, was downscaled to the Simpevarp investigation area. The downscaled DGVM was evaluated against measured respiration and soil organic acids for all five ecosystems. In meadow, it was evaluated against Net Primary Production, NPP. For the forest ecosystems, it was evaluated against tree layer carbon pools. The evaluation indicated that the DGVM is reasonably well downscaled to the Simpevarp investigation area and

Aspects of the carbon cycle in terrestrial ecosystems of Northeastern Smaaland

International Nuclear Information System (INIS)

Tagesson, Torbern

2006-02-01

Boreal and temperate ecosystems of the northern hemisphere are important for the future development of global climate. In this study, the carbon cycle has been studied in a pine forest, a meadow, a spruce forest and two deciduous forests in the Simpevarp investigation area in southern Sweden (57 deg 5 min N, 34 deg 55 min E). Ground respiration and ground Gross Primary Production (GPP) has been measured three times during spring 2004 with the closed chamber technique. Soil temperature, soil moisture and Photosynthetically Active Radiation (PAR) were also measured. An exponential regression with ground respiration against soil temperature was used to extrapolate respiration over spring 2004. A logarithmic regression with ground GPP against PAR was used to extrapolate GPP in meadow over spring 2004. Ground respiration is affected by soil temperature in all ecosystems but pine, but still it only explains a small part of the variation in respiration and this indicates that other abiotic factors also have an influence. Soil moisture affects respiration in spruce and one of the deciduous ecosystems. A comparison between measured and extrapolated ground respiration indicated that soil temperature could be used to extrapolate ground respiration. PAR is the main factor influencing GPP in all ecosystems but pine, still it could not be used to extrapolate GPP in meadow since too few measurements were done and they were from different periods of spring. Soil moisture did not have any significant effect on GPP. A Dynamic Global Vegetation Model, a DGVM called LPJ-GUESS, was downscaled to the Simpevarp investigation area. The downscaled DGVM was evaluated against measured respiration and soil organic acids for all five ecosystems. In meadow, it was evaluated against Net Primary Production, NPP. For the forest ecosystems, it was evaluated against tree layer carbon pools. The evaluation indicated that the DGVM is reasonably well downscaled to the Simpevarp investigation area and

Global biogeographical pattern of ecosystem functional types derived from earth observation data

DEFF Research Database (Denmark)

Ivits, Eva; Cherlet, Michael; Horion, Stéphanie Marie Anne F

2013-01-01

correspondence of the EFTs to global climate and also to land use classification. The results show the great potential of Earth Observation derived parameters for the quantification of ecosystem functional dynamics and for providing reference status information for future assessments of ecosystem changes........ The association of the EFTs with existing climate and land cover classifications was demonstrated via Detrended Correspondence Analysis (DCA). The ordination indicated good description of the global environmental gradient by the EFTs, supporting the understanding of phenological and productivity dynamics...... of global ecosystems. Climatic constraints of vegetation growth explained 50% of variation in the phenological data along the EFTs showing that part of the variation in the global phenological gradient is not climate related but is unique to the Earth Observation derived variables. DCA demonstrated good...

Exploring the Red Sea seasonal ecosystem functioning using a three-dimensional biophysical model

KAUST Repository

Triantafyllou, G.; Yao, F.; Petihakis, G.; Tsiaras, K. P.; Raitsos, D. E.; Hoteit, Ibrahim

2014-01-01

The Red Sea exhibits complex hydrodynamic and biogeochemical dynamics, which vary both in time and space. These dynamics have been explored through the development and application of a 3-D ecosystem model. The simulation system comprises two off-line coupled submodels: the MIT General Circulation Model (MITgcm) and the European Regional Seas Ecosystem Model (ERSEM), both adapted for the Red Sea. The results from an annual simulation under climatological forcing are presented. Simulation results are in good agreement with satellite and in situ data illustrating the role of the physical processes in determining the evolution and variability of the Red Sea ecosystem. The model was able to reproduce the main features of the Red Sea ecosystem functioning, including the exchange with the Gulf of Aden, which is a major driving mechanism for the whole Red Sea ecosystem and the winter overturning taking place in the north. Some model limitations, mainly related to the dynamics of the extended reef system located in the southern part of the Red Sea, which is not currently represented in the model, still need to be addressed.

Exploring the Red Sea seasonal ecosystem functioning using a three-dimensional biophysical model

KAUST Repository

Triantafyllou, G.

2014-03-01

The Red Sea exhibits complex hydrodynamic and biogeochemical dynamics, which vary both in time and space. These dynamics have been explored through the development and application of a 3-D ecosystem model. The simulation system comprises two off-line coupled submodels: the MIT General Circulation Model (MITgcm) and the European Regional Seas Ecosystem Model (ERSEM), both adapted for the Red Sea. The results from an annual simulation under climatological forcing are presented. Simulation results are in good agreement with satellite and in situ data illustrating the role of the physical processes in determining the evolution and variability of the Red Sea ecosystem. The model was able to reproduce the main features of the Red Sea ecosystem functioning, including the exchange with the Gulf of Aden, which is a major driving mechanism for the whole Red Sea ecosystem and the winter overturning taking place in the north. Some model limitations, mainly related to the dynamics of the extended reef system located in the southern part of the Red Sea, which is not currently represented in the model, still need to be addressed.

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

DEFF Research Database (Denmark)

Babst, Flurin; Bouriaud, Olivier; Papale, Dario

2014-01-01

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...

Ground-water temperature of the Wyoming quadrangle in central Delaware : with application to ground-water-source heat pumps

Science.gov (United States)

Hodges, Arthur L.

1982-01-01

Ground-water temperature was measured during a one-year period (1980-81) in 20 wells in the Wyoming Quadrangle in central Delaware. Data from thermistors set at fixed depths in two wells were collected twice each week, and vertical temperature profiles of the remaining 18 wells were made monthly. Ground-water temperature at 8 feet below land surface in well Jc55-1 ranged from 45.0 degrees F in February to 70.1 degrees F in September. Temperature at 35 feet below land surface in the same well reached a minimum of 56.0 degrees F in August, and a maximum of 57.8 degrees F in February. Average annual temperature of ground water at 25 feet below land surface in all wells ranged from 54.6 degrees F to 57.8 degrees F. Variations of average temperature probably reflect the presence or absence of forestation in the recharge areas of the wells. Ground-water-source heat pumps supplied with water from wells 30 or more feet below land surface will operate more efficiently in both heating and cooling modes than those supplied with water from shallower depths. (USGS)

Positive plant diversity-soil stability relationships are mediated through roots in the Songnen Grassland: Chronosequence evidence

Science.gov (United States)

Liang-Jun Hu; Ping Li; Qinfeng Guo

2013-01-01

Living plant diversity (excluding the litter issue) may affect below-ground properties and processes, which is critical to obtaining an integrated biodiversity-ecosystem functioning theory. However, related patterns and underlying mechanisms have rarely been examined, especially lacking long-term evidence. We conducted a factorial crossed sample survey to examine the...

A stable isotopic view on lianas' and trees' below ground competition for water

Science.gov (United States)

De Deurwaerder, Hannes; Hervé-Fernández, Pedro; Stahl, Clément; Bonal, Damien; Burban, Benoît; Petronelli, Pascal; Boeckx, Pascal; Verbeeck, Hans

2017-04-01

Various studies highlight an increase in liana abundance and biomass in the neotropics in the last decades. To date, the reason why this growth form expresses this trend is still unclear. One of the proposed hypotheses ascribes tropical lianas, in comparison to tropical trees, of being able to adapt better to increased drought conditions resulting from climate change. Moreover, lianas presumably have a deeper root system, providing access to deeper soil layers less susceptible for dehydration during drought events. A dual stable water isotopic approach (δ18O and δ2H) enables studying vegetation below ground competition and in combination with Bayesian mixing models can provide insight in the fractional contribution of distinct soil layer depths. In this perspective, precipitation (bulk and through fall), bulk soil (at different depths), stream and xylem water of both lianas and trees were sampled between October 7-13, 2015. The study focusses on two distinct plots differing in soil texture (sand and clay), localized in close vicinity of the Guyana flux tower at Paracou (French Guyana). Our study highlights the erroneous of the deep tap root hypothesis and provides new insights in water and nutrient competition between tropical lianas and trees during dry season. Lianas isotopic signature is enriched compared to those of trees. This can be linked to water source depth and soil seasonal replenishment. Moreover, liana displaying a very active soil surface root activity, efficiently capturing the low amount of dry season precipitation, while trees show to tap the deeper and less drought susceptible soil layers. A strategy, which not only results in a spatial niche separation in the underground competition for water, but it also provides lianas with a definite advantage in nutrient competition.

The functional value of Caribbean coral reef, seagrass and mangrove habitats to ecosystem processes.

Science.gov (United States)

Harborne, Alastair R; Mumby, Peter J; Micheli, Fiorenza; Perry, Christopher T; Dahlgren, Craig P; Holmes, Katherine E; Brumbaugh, Daniel R

2006-01-01

Caribbean coral reef habitats, seagrass beds and mangroves provide important goods and services both individually and through functional linkages. A range of anthropogenic factors are threatening the ecological and economic importance of these habitats and it is vital to understand how ecosystem processes vary across seascapes. A greater understanding of processes will facilitate further insight into the effects of disturbances and assist with assessing management options. Despite the need to study processes across whole seascapes, few spatially explicit ecosystem-scale assessments exist. We review the empirical literature to examine the role of different habitat types for a range of processes. The importance of each of 10 generic habitats to each process is defined as its "functional value" (none, low, medium or high), quantitatively derived from published data wherever possible and summarised in a single figure. This summary represents the first time the importance of habitats across an entire Caribbean seascape has been assessed for a range of processes. Furthermore, we review the susceptibility of each habitat to disturbances to investigate spatial patterns that might affect functional values. Habitat types are considered at the scale discriminated by remotely-sensed imagery and we envisage that functional values can be combined with habitat maps to provide spatially explicit information on processes across ecosystems. We provide examples of mapping the functional values of habitats for populations of three commercially important species. The resulting data layers were then used to generate seascape-scale assessments of "hot spots" of functional value that might be considered priorities for conservation. We also provide an example of how the literature reviewed here can be used to parameterise a habitat-specific model investigating reef resilience under different scenarios of herbivory. Finally, we use multidimensional scaling to provide a basic analysis of the

Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier.

Science.gov (United States)

Horion, Stéphanie; Prishchepov, Alexander V; Verbesselt, Jan; de Beurs, Kirsten; Tagesson, Torbern; Fensholt, Rasmus

2016-08-01

The collapse of the Soviet Union in 1991 has been a turning point in the World history that left a unique footprint on the Northern Eurasian ecosystems. Conducting large scale mapping of environmental change and separating between naturogenic and anthropogenic drivers is a difficult endeavor in such highly complex systems. In this research a piece-wise linear regression method was used for breakpoint detection in Rain-Use Efficiency (RUE) time series and a classification of ecosystem response types was produced. Supported by earth observation data, field data, and expert knowledge, this study provides empirical evidence regarding the occurrence of drastic changes in RUE (assessment of the timing, the direction and the significance of these changes) in Northern Eurasian ecosystems between 1982 and 2011. About 36% of the study area (3.4 million km(2) ) showed significant (P agricultural land abandonment. Our study also showed that recurrent droughts deeply affected vegetation productivity throughout the observation period, with a general worsening of the drought conditions in recent years. Moreover, recent human-induced turning points in ecosystem functioning were detected and attributed to ongoing recultivation and change in irrigation practices in the Volgograd region, and to increased salinization and increased grazing intensity around Lake Balkhash. The ecosystem-state assessment method introduced here proved to be a valuable support that highlighted hotspots of potentially altered ecosystems and allowed for disentangling human from climatic disturbances. © 2016 John Wiley & Sons Ltd.

Land-use choices follow profitability at the expense of ecological functions in Indonesian smallholder landscapes.

Science.gov (United States)

Clough, Yann; Krishna, Vijesh V; Corre, Marife D; Darras, Kevin; Denmead, Lisa H; Meijide, Ana; Moser, Stefan; Musshoff, Oliver; Steinebach, Stefanie; Veldkamp, Edzo; Allen, Kara; Barnes, Andrew D; Breidenbach, Natalie; Brose, Ulrich; Buchori, Damayanti; Daniel, Rolf; Finkeldey, Reiner; Harahap, Idham; Hertel, Dietrich; Holtkamp, A Mareike; Hörandl, Elvira; Irawan, Bambang; Jaya, I Nengah Surati; Jochum, Malte; Klarner, Bernhard; Knohl, Alexander; Kotowska, Martyna M; Krashevska, Valentyna; Kreft, Holger; Kurniawan, Syahrul; Leuschner, Christoph; Maraun, Mark; Melati, Dian Nuraini; Opfermann, Nicole; Pérez-Cruzado, César; Prabowo, Walesa Edho; Rembold, Katja; Rizali, Akhmad; Rubiana, Ratna; Schneider, Dominik; Tjitrosoedirdjo, Sri Sudarmiyati; Tjoa, Aiyen; Tscharntke, Teja; Scheu, Stefan

2016-10-11

Smallholder-dominated agricultural mosaic landscapes are highlighted as model production systems that deliver both economic and ecological goods in tropical agricultural landscapes, but trade-offs underlying current land-use dynamics are poorly known. Here, using the most comprehensive quantification of land-use change and associated bundles of ecosystem functions, services and economic benefits to date, we show that Indonesian smallholders predominantly choose farm portfolios with high economic productivity but low ecological value. The more profitable oil palm and rubber monocultures replace forests and agroforests critical for maintaining above- and below-ground ecological functions and the diversity of most taxa. Between the monocultures, the higher economic performance of oil palm over rubber comes with the reliance on fertilizer inputs and with increased nutrient leaching losses. Strategies to achieve an ecological-economic balance and a sustainable management of tropical smallholder landscapes must be prioritized to avoid further environmental degradation.

Land-use choices follow profitability at the expense of ecological functions in Indonesian smallholder landscapes

Science.gov (United States)

Clough, Yann; Krishna, Vijesh V.; Corre, Marife D.; Darras, Kevin; Denmead, Lisa H.; Meijide, Ana; Moser, Stefan; Musshoff, Oliver; Steinebach, Stefanie; Veldkamp, Edzo; Allen, Kara; Barnes, Andrew D.; Breidenbach, Natalie; Brose, Ulrich; Buchori, Damayanti; Daniel, Rolf; Finkeldey, Reiner; Harahap, Idham; Hertel, Dietrich; Holtkamp, A. Mareike; Hörandl, Elvira; Irawan, Bambang; Jaya, I. Nengah Surati; Jochum, Malte; Klarner, Bernhard; Knohl, Alexander; Kotowska, Martyna M.; Krashevska, Valentyna; Kreft, Holger; Kurniawan, Syahrul; Leuschner, Christoph; Maraun, Mark; Melati, Dian Nuraini; Opfermann, Nicole; Pérez-Cruzado, César; Prabowo, Walesa Edho; Rembold, Katja; Rizali, Akhmad; Rubiana, Ratna; Schneider, Dominik; Tjitrosoedirdjo, Sri Sudarmiyati; Tjoa, Aiyen; Tscharntke, Teja; Scheu, Stefan

2016-10-01

Smallholder-dominated agricultural mosaic landscapes are highlighted as model production systems that deliver both economic and ecological goods in tropical agricultural landscapes, but trade-offs underlying current land-use dynamics are poorly known. Here, using the most comprehensive quantification of land-use change and associated bundles of ecosystem functions, services and economic benefits to date, we show that Indonesian smallholders predominantly choose farm portfolios with high economic productivity but low ecological value. The more profitable oil palm and rubber monocultures replace forests and agroforests critical for maintaining above- and below-ground ecological functions and the diversity of most taxa. Between the monocultures, the higher economic performance of oil palm over rubber comes with the reliance on fertilizer inputs and with increased nutrient leaching losses. Strategies to achieve an ecological-economic balance and a sustainable management of tropical smallholder landscapes must be prioritized to avoid further environmental degradation.

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. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

A new method for large-scale assessment of change in ecosystem functioning in relation to land degradation

Science.gov (United States)

Horion, Stephanie; Ivits, Eva; Verzandvoort, Simone; Fensholt, Rasmus

2017-04-01

Ongoing pressures on European land are manifold with extreme climate events and non-sustainable use of land resources being amongst the most important drivers altering the functioning of the ecosystems. The protection and conservation of European natural capital is one of the key objectives of the 7th Environmental Action Plan (EAP). The EAP stipulates that European land must be managed in a sustainable way by 2020 and the UN Sustainable development goals define a Land Degradation Neutral world as one of the targets. This implies that land degradation (LD) assessment of European ecosystems must be performed repeatedly allowing for the assessment of the current state of LD as well as changes compared to a baseline adopted by the UNCCD for the objective of land degradation neutrality. However, scientifically robust methods are still lacking for large-scale assessment of LD and repeated consistent mapping of the state of terrestrial ecosystems. Historical land degradation assessments based on various methods exist, but methods are generally non-replicable or difficult to apply at continental scale (Allan et al. 2007). The current lack of research methods applicable at large spatial scales is notably caused by the non-robust definition of LD, the scarcity of field data on LD, as well as the complex inter-play of the processes driving LD (Vogt et al., 2011). Moreover, the link between LD and changes in land use (how land use changes relates to change in vegetation productivity and ecosystem functioning) is not straightforward. In this study we used the segmented trend method developed by Horion et al. (2016) for large-scale systematic assessment of hotspots of change in ecosystem functioning in relation to LD. This method alleviates shortcomings of widely used linear trend model that does not account for abrupt change, nor adequately captures the actual changes in ecosystem functioning (de Jong et al. 2013; Horion et al. 2016). Here we present a new methodology for

Detecting forest cover and ecosystem service change using ...

African Journals Online (AJOL)

Natural forests in Uganda have experienced both spatial and temporal modifications from different drivers which need to be monitored to assess the impacts of such changes on ecosystems and prevent related risks of reduction in ecosystem service benefits. Ground investigations may be complex because of dual ...

Biodiversity and Ecosystem Functioning: Exploring Principles of Ecology with Agricultural Plants

Science.gov (United States)

Ruesink, Jennifer; O'Connor, Eileen; Sparks, Grace

2006-01-01

To date, little of the ecological research on biological diversity and ecosystem functioning has been carried out in agricultural systems, despite the fact that agriculture is a major contributor to loss of native habitats and species. However, agricultural research has demonstrated that polycultures of multiple crop species can have higher total…

The resilience and functional role of moss in boreal and arctic ecosystems

Science.gov (United States)

Turetsky, M.; Bond-Lamberty, B.; Euskirchen, E.S.; Talbot, J. J.; Frolking, S.; McGuire, A.D.; Tuittila, E.S.

2012-01-01

Mosses in northern ecosystems are ubiquitous components of plant communities, and strongly influence nutrient, carbon and water cycling. We use literature review, synthesis and model simulations to explore the role of mosses in ecological stability and resilience. Moss community responses to disturbance showed all possible responses (increases, decreases, no change) within most disturbance categories. Simulations from two process-based models suggest that northern ecosystems would need to experience extreme perturbation before mosses were eliminated. But simulations with two other models suggest that loss of moss will reduce soil carbon accumulation primarily by influencing decomposition rates and soil nitrogen availability. It seems clear that mosses need to be incorporated into models as one or more plant functional types, but more empirical work is needed to determine how to best aggregate species. We highlight several issues that have not been adequately explored in moss communities, such as functional redundancy and singularity, relationships between response and effect traits, and parameter vs conceptual uncertainty in models. Mosses play an important role in several ecosystem processes that play out over centuries – permafrost formation and thaw, peat accumulation, development of microtopography – and there is a need for studies that increase our understanding of slow, long-term dynamical processes.

The resilience and functional role of moss in boreal and arctic ecosystems.

Science.gov (United States)

Turetsky, M R; Bond-Lamberty, B; Euskirchen, E; Talbot, J; Frolking, S; McGuire, A D; Tuittila, E-S

2012-10-01

Mosses in northern ecosystems are ubiquitous components of plant communities, and strongly influence nutrient, carbon and water cycling. We use literature review, synthesis and model simulations to explore the role of mosses in ecological stability and resilience. Moss community responses to disturbance showed all possible responses (increases, decreases, no change) within most disturbance categories. Simulations from two process-based models suggest that northern ecosystems would need to experience extreme perturbation before mosses were eliminated. But simulations with two other models suggest that loss of moss will reduce soil carbon accumulation primarily by influencing decomposition rates and soil nitrogen availability. It seems clear that mosses need to be incorporated into models as one or more plant functional types, but more empirical work is needed to determine how to best aggregate species. We highlight several issues that have not been adequately explored in moss communities, such as functional redundancy and singularity, relationships between response and effect traits, and parameter vs conceptual uncertainty in models. Mosses play an important role in several ecosystem processes that play out over centuries - permafrost formation and thaw, peat accumulation, development of microtopography - and there is a need for studies that increase our understanding of slow, long-term dynamical processes. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Soil "ecosystem" services and natural capital: Critical appraisal of research on uncertain ground

Directory of Open Access Journals (Sweden)

Philippe C. Baveye

2016-06-01

Full Text Available Over the last few years, considerable attention has been devoted in the scientific literature and in the media to the concept of ecosystem services of soils. The monetary valuation of these services, demanded by many governments and international agencies, is often depicted as a necessary condition for the preservation of the natural capital that soils represent. This focus on soil services is framed in the context of a general interest in ecosystem services that allegedly started in 1997, and took off in earnest after 2005. The careful analysis of the literature proposed in this article shows that, in fact, interest in the multifunctionality of soils emerged already in the mid-60s, at a time when hundreds of researchers worldwide were trying, and largely failing, to figure out how to put price tags meaningfully on nature's services. Soil scientists, since, have tried to better understand various functions/services of soils, as well as their possible relation with key soil characteristics, like biodiversity. They have also tried to make progress on the challenging quantification of soil functions/services. However, researchers have shown very little interest in monetary valuation, undoubtedly in part because it is not clear what economic and financial markets might do with prices of soil functions/services, even if we could somehow come up with such numbers, and because there is no assurance at all, based on neoclassical economic theory, that markets would manage soil resources optimally. Instead of monetary valuation, focus in the literature has been put on decision-making methods, like Multi-Criteria Decision Analysis (MCDA and Bayesian Belief Networks (BBN, which do not require the systematic monetization of soil functions/services and easily accommodate deliberative approaches involving a variety of stakeholders. A prerequisite to progress in such public deliberations is that participants be very cognizant of the extreme relevance of soils

Effects on the function of Arctic ecosystems in the short- and long-term perspectives.

Science.gov (United States)

Callaghan, Terry V; Björn, Lars Olof; Chernov, Yuri; Chapin, Terry; Christensen, Torben R; Huntley, Brian; Ims, Rolf A; Johansson, Margareta; Jolly, Dyanna; Jonasson, Sven; Matveyeva, Nadya; Panikov, Nicolai; Oechel, Walter; Shaver, Gus

2004-11-01

Historically, the function of Arctic ecosystems in terms of cycles of nutrients and carbon has led to low levels of primary production and exchanges of energy, water and greenhouse gases have led to low local and regional cooling. Sequestration of carbon from atmospheric CO2, in extensive, cold organic soils and the high albedo from low, snow-covered vegetation have had impacts on regional climate. However, many aspects of the functioning of Arctic ecosystems are sensitive to changes in climate and its impacts on biodiversity. The current Arctic climate results in slow rates of organic matter decomposition. Arctic ecosystems therefore tend to accumulate organic matter and elements despite low inputs. As a result, soil-available elements like nitrogen and phosphorus are key limitations to increases in carbon fixation and further biomass and organic matter accumulation. Climate warming is expected to increase carbon and element turnover, particularly in soils, which may lead to initial losses of elements but eventual, slow recovery. Individual species and species diversity have clear impacts on element inputs and retention in Arctic ecosystems. Effects of increased CO2 and UV-B on whole ecosystems, on the other hand, are likely to be small although effects on plant tissue chemisty, decomposition and nitrogen fixation may become important in the long-term. Cycling of carbon in trace gas form is mainly as CO2 and CH4. Most carbon loss is in the form of CO2, produced by both plants and soil biota. Carbon emissions as methane from wet and moist tundra ecosystems are about 5% of emissions as CO2 and are responsive to warming in the absence of any other changes. Winter processes and vegetation type also affect CH4 emissions as well as exchanges of energy between biosphere and atmosphere. Arctic ecosystems exhibit the largest seasonal changes in energy exchange of any terrestrial ecosystem because of the large changes in albedo from late winter, when snow reflects most

Complex effects of ecosystem engineer loss on benthic ecosystem response to detrital macroalgae

NARCIS (Netherlands)

Rossi, F.; Gribsholt, B.; Gazeau, F.; Di Santo, V.; Middelburg, J.J.

2013-01-01

Ecosystem engineers change abiotic conditions, community assembly and ecosystem functioning. Consequently, their loss may modify thresholds of ecosystem response to disturbance and undermine ecosystem stability. This study investigates how loss of the bioturbating lugworm Arenicola marina modifies

Complex Effects of Ecosystem Engineer Loss on Benthic Ecosystem Response to Detrital Macroalgae

NARCIS (Netherlands)

Rossi, F.; Gribsholt, B.; Gazeau, F.; Di Santo, V.; Middelburg, J.J.

2013-01-01

Ecosystem engineers change abiotic conditions, community assembly and ecosystem functioning. Consequently, their loss may modify thresholds of ecosystem response to disturbance and undermine ecosystem stability. This study investigates how loss of the bioturbating lugworm Arenicola marina modifies

Too big or too narrow? Disturbance characteristics determine the functional resilience in virtual microbial ecosystems

Science.gov (United States)

König, Sara; Firle, Anouk-Letizia; Koehnke, Merlin; Banitz, Thomas; Frank, Karin

2017-04-01

In general ecology, there is an ongoing debate about the influence of fragmentation on extinction thresholds. Whether this influence is positive or negative depends on the considered type of fragmentation: whereas habitat fragmentation often has a negative influence on population extinction thresholds, spatially fragmented disturbances are observed to have mostly positive effects on the extinction probability. Besides preventing population extinction, in soil systems ecology we are interested in analyzing how ecosystem functions are maintained despite disturbance events. Here, we analyzed the influence of disturbance size and fragmentation on the functional resilience of a microbial soil ecosystem. As soil is a highly heterogeneous environment exposed to disturbances of different spatial configurations, the identification of critical disturbance characteristics for maintaining its functions is crucial. We used the numerical simulation model eColony considering bacterial growth, degradation and dispersal for analyzing the dynamic response of biodegradation examplary for an important microbial ecosystem service to disturbance events of different spatial configurations. We systematically varied the size and the degree of fragmentation of the affected area (disturbance pattern). We found that the influence of the disturbance size on functional recovery and biodegradation performance highly depends on the spatial fragmentation of the disturbance. Generally, biodegradation performance decreases with increasing clumpedness and increasing size of the affected area. After spatially correlated disturbance events, biodegradation performance decreases linear with increasing disturbance size. After spatially fragmented disturbance events, on the other hand, an increase in disturbance size has no influence on the biodegradation performance until a critical disturbance size is reached. Is the affected area bigger than this critical size, the functional performance decreases

Geology and biology of the "Sticky Grounds," shelf-margin carbonate mounds, and mesophotic ecosystem in the eastern Gulf of Mexico

Science.gov (United States)

Locker, Stanley D.; Reed, John K.; Farrington, Stephanie; Harter, Stacey; Hine, Albert C.; Dunn, Shane

2016-01-01

Shelf-margin carbonate mounds in water depths of 116–135 m in the eastern Gulf of Mexico along the central west Florida shelf were investigated using swath bathymetry, side-scan sonar, sub-bottom imaging, rock dredging, and submersible dives. These enigmatic structures, known to fisherman as the “Sticky Grounds”, trend along slope, are 5–15 m in relief with base diameters of 5–30 m, and suggest widespread potential for mesophotic reef habitat along the west Florida outer continental shelf. Possible origins are sea-level lowstand coral patch reefs, oyster reefs, or perhaps more recent post-lowstand biohermal development. Rock dredging recovered bioeroded carbonate-rock facies comprised of bored and cemented bioclastics. Rock sample components included calcified worm tubes, pelagic sediment, and oysters normally restricted to brackish nearshore areas. Several reef sites were surveyed at the Sticky Grounds during a cruise in August 2010 with the R/V Seward Johnson using the Johnson-Sea-Link II submersible to ground truth the swath-sonar maps and to quantify and characterize the benthic habitats, benthic macrofauna, fish populations, and coral/sponge cover. This study characterizes for the first time this mesophotic reef ecosystem and associated fish populations, and analyzes the interrelationships of the fish assemblages, benthic habitats and invertebrate biota. These highly eroded rock mounds provide extensive hard-bottom habitat for reef invertebrate species as well as essential fish habitat for reef fish and commercially/recreationally important fish species. The extent and significance of associated living resources with these bottom types is particularly important in light of the 2010 Deepwater Horizon oil spill in the northeastern Gulf and the proximity of the Loop Current. Mapping the distribution of these mesophotic-depth ecosystems is important for quantifying essential fish habitat and describing benthic resources. These activities can improve

Taking a closer look: disentangling effects of functional diversity on ecosystem functions with a trait-based model across hierarchy and time

Science.gov (United States)

Holzwarth, Frédéric; Rüger, Nadja; Wirth, Christian

2015-01-01

Biodiversity and ecosystem functioning (BEF) research has progressed from the detection of relationships to elucidating their drivers and underlying mechanisms. In this context, replacing taxonomic predictors by trait-based measures of functional composition (FC)—bridging functions of species and of ecosystems—is a widely used approach. The inherent challenge of trait-based approaches is the multi-faceted, dynamic and hierarchical nature of trait influence: (i) traits may act via different facets of their distribution in a community, (ii) their influence may change over time and (iii) traits may influence processes at different levels of the natural hierarchy of organization. Here, we made use of the forest ecosystem model ‘LPJ-GUESS’ parametrized with empirical trait data, which creates output of individual performance, community assembly, stand-level states and processes. To address the three challenges, we resolved the dynamics of the top-level ecosystem function ‘annual biomass change’ hierarchically into its various component processes (growth, leaf and root turnover, recruitment and mortality) and states (stand structures, water stress) and traced the influence of different facets of FC along this hierarchy in a path analysis. We found an independent influence of functional richness, dissimilarity and identity on ecosystem states and processes and hence biomass change. Biodiversity effects were only positive during early succession and later turned negative. Unexpectedly, resource acquisition (growth, recruitment) and conservation (mortality, turnover) played an equally important role throughout the succession. These results add to a mechanistic understanding of biodiversity effects and place a caveat on simplistic approaches omitting hierarchical levels when analysing BEF relationships. They support the view that BEF relationships experience dramatic shifts over successional time that should be acknowledged in mechanistic theories. PMID:26064620

Effects of drought and irrigation on ecosystem functioning in a mature Scots pine forest

Science.gov (United States)

Dobbertin, Matthias; Brunner, Ivano; Egli, Simon; Eilmann, Britta; Graf Pannatier, Eisabeth; Schleppi, Patrick; Zingg, Andreas; Rigling, Andreas

2010-05-01

Climate change is expected to increase temperature and reduce summer precipitation in Switzerland. To study the expected effects of increased drought in mature forests two different approaches are in general possible: water can be partially or completely removed from the ecosystems via above- or below-canopy roofs or water can be added to already drought-prone ecosystems. Both methods have advantages and disadvantages. In our study water was added to a mature 90-year old Scots pine (Pinus sylvestris L.) forest with a few singe pubescent oaks (Quercus pubescens Willd.), located in the valley bottom of the driest region of Switzerland (Valais). In Valais, Scots pines are declining, usually with increased mortality rates following drought years. It was therefore of special interest to study here how water addition is changing forest ecosystem functioning. The irrigation experiment started in the summer of 2003. Out of eight 0.1 ha experimental plots, four were randomly selected for irrigation, the other four left as a control. Irrigation occurred during rainless nights between April and October, doubling the annual rainfall amount from 650 to 1300 mm. Irrigation water, taken from a near-by irrigation channel, added some nutrients to the plots, but nutrients which were deficient on the site, e.g. nitrogen and phosphorus, were not altered. Tree diameter, tree height and crown width were assessed before the start of the irrigation in winter 2002/2003 and after 7 years of the experiment in 2009/2010. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Additionally, tree mortality was annually evaluated. Mycorrhizal fruit bodies were identified and counted at weekly intervals from 2003 until 2007. Root samples were taken in 2004 and 2005. In 2004 and 2005 wood formation of thirteen trees was analysed in weekly or biweekly intervals using the pinning method. These trees were felled in 2006 for stem, shoot and needle growth analysis

Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

Science.gov (United States)

Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

2015-08-11

The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

Testing the generality of above-ground biomass allometry across plant functional types at the continent scale.

Science.gov (United States)

Paul, Keryn I; Roxburgh, Stephen H; Chave, Jerome; England, Jacqueline R; Zerihun, Ayalsew; Specht, Alison; Lewis, Tom; Bennett, Lauren T; Baker, Thomas G; Adams, Mark A; Huxtable, Dan; Montagu, Kelvin D; Falster, Daniel S; Feller, Mike; Sochacki, Stan; Ritson, Peter; Bastin, Gary; Bartle, John; Wildy, Dan; Hobbs, Trevor; Larmour, John; Waterworth, Rob; Stewart, Hugh T L; Jonson, Justin; Forrester, David I; Applegate, Grahame; Mendham, Daniel; Bradford, Matt; O'Grady, Anthony; Green, Daryl; Sudmeyer, Rob; Rance, Stan J; Turner, John; Barton, Craig; Wenk, Elizabeth H; Grove, Tim; Attiwill, Peter M; Pinkard, Elizabeth; Butler, Don; Brooksbank, Kim; Spencer, Beren; Snowdon, Peter; O'Brien, Nick; Battaglia, Michael; Cameron, David M; Hamilton, Steve; McAuthur, Geoff; Sinclair, Jenny

2016-06-01

Accurate ground-based estimation of the carbon stored in terrestrial ecosystems is critical to quantifying the global carbon budget. Allometric models provide cost-effective methods for biomass prediction. But do such models vary with ecoregion or plant functional type? We compiled 15 054 measurements of individual tree or shrub biomass from across Australia to examine the generality of allometric models for above-ground biomass prediction. This provided a robust case study because Australia includes ecoregions ranging from arid shrublands to tropical rainforests, and has a rich history of biomass research, particularly in planted forests. Regardless of ecoregion, for five broad categories of plant functional type (shrubs; multistemmed trees; trees of the genus Eucalyptus and closely related genera; other trees of high wood density; and other trees of low wood density), relationships between biomass and stem diameter were generic. Simple power-law models explained 84-95% of the variation in biomass, with little improvement in model performance when other plant variables (height, bole wood density), or site characteristics (climate, age, management) were included. Predictions of stand-based biomass from allometric models of varying levels of generalization (species-specific, plant functional type) were validated using whole-plot harvest data from 17 contrasting stands (range: 9-356 Mg ha(-1) ). Losses in efficiency of prediction were <1% if generalized models were used in place of species-specific models. Furthermore, application of generalized multispecies models did not introduce significant bias in biomass prediction in 92% of the 53 species tested. Further, overall efficiency of stand-level biomass prediction was 99%, with a mean absolute prediction error of only 13%. Hence, for cost-effective prediction of biomass across a wide range of stands, we recommend use of generic allometric models based on plant functional types. Development of new species

Tradeoffs between income, biodiversity, and ecosystem functioning during tropical rainforest conversion and agroforestry intensification.

Science.gov (United States)

Steffan-Dewenter, Ingolf; Kessler, Michael; Barkmann, Jan; Bos, Merijn M; Buchori, Damayanti; Erasmi, Stefan; Faust, Heiko; Gerold, Gerhard; Glenk, Klaus; Gradstein, S Robbert; Guhardja, Edi; Harteveld, Marieke; Hertel, Dietrich; Höhn, Patrick; Kappas, Martin; Köhler, Stefan; Leuschner, Christoph; Maertens, Miet; Marggraf, Rainer; Migge-Kleian, Sonja; Mogea, Johanis; Pitopang, Ramadhaniel; Schaefer, Matthias; Schwarze, Stefan; Sporn, Simone G; Steingrebe, Andrea; Tjitrosoedirdjo, Sri S; Tjitrosoemito, Soekisman; Twele, André; Weber, Robert; Woltmann, Lars; Zeller, Manfred; Tscharntke, Teja

2007-03-20

Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by approximately 75% and species richness of forest-using species by approximately 60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by approximately 40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends.

Body condition, diet and ecosystem function of red deer (Cervus elaphus) in a fenced nature reserve

DEFF Research Database (Denmark)

Fløjgaard, Camilla; De Barba, Marta; Taberlet, Pierre

2017-01-01

is therefore relevant to increase understanding of herbivores' ecosystem function and to inform management. In this study, we focused on red deer, Cervus elaphus, in a fenced nature reserve in Denmark, where the deer are managed as ecosystem engineers to contribute to biodiversity conservation. We measured...... on variation in body condition within the population. Our findings call for the need to consider the consequences of management practices, including culling or supplemental feeding, on the outcomes of habitat restoration, and more broadly underline the importance of preserving the overall breath of herbivore...... ecosystem functions for effective biodiversity conservation....

Changes in food web structure and ecosystem functioning of a large, shallow Chinese lake during the 1950s, 1980s and 2000s

NARCIS (Netherlands)

Kong, Xiangzhen; He, Wei; Liu, Wenxiu; Yang, Bin; Xu, Fuliu; Jørgensen, Sven Erik; Mooij, W.M.

2016-01-01

Food web structure dynamics and ecosystem functioning are strongly linked, and both are indispensable in evaluating ecosystem development in lakes under multiple anthropogenic stressors. However, model-based approaches concerning the changes in food web structure and ecosystem functioning in a

Scientific Foundations for an IUCN Red List of Ecosystems

Science.gov (United States)

Keith, David A.; Rodríguez, Jon Paul; Rodríguez-Clark, Kathryn M.; Nicholson, Emily; Aapala, Kaisu; Alonso, Alfonso; Asmussen, Marianne; Bachman, Steven; Basset, Alberto; Barrow, Edmund G.; Benson, John S.; Bishop, Melanie J.; Bonifacio, Ronald; Brooks, Thomas M.; Burgman, Mark A.; Comer, Patrick; Comín, Francisco A.; Essl, Franz; Faber-Langendoen, Don; Fairweather, Peter G.; Holdaway, Robert J.; Jennings, Michael; Kingsford, Richard T.; Lester, Rebecca E.; Nally, Ralph Mac; McCarthy, Michael A.; Moat, Justin; Oliveira-Miranda, María A.; Pisanu, Phil; Poulin, Brigitte; Regan, Tracey J.; Riecken, Uwe; Spalding, Mark D.; Zambrano-Martínez, Sergio

2013-01-01

An understanding of risks to biodiversity is needed for planning action to slow current rates of decline and secure ecosystem services for future human use. Although the IUCN Red List criteria provide an effective assessment protocol for species, a standard global assessment of risks to higher levels of biodiversity is currently limited. In 2008, IUCN initiated development of risk assessment criteria to support a global Red List of ecosystems. We present a new conceptual model for ecosystem risk assessment founded on a synthesis of relevant ecological theories. To support the model, we review key elements of ecosystem definition and introduce the concept of ecosystem collapse, an analogue of species extinction. The model identifies four distributional and functional symptoms of ecosystem risk as a basis for assessment criteria: A) rates of decline in ecosystem distribution; B) restricted distributions with continuing declines or threats; C) rates of environmental (abiotic) degradation; and D) rates of disruption to biotic processes. A fifth criterion, E) quantitative estimates of the risk of ecosystem collapse, enables integrated assessment of multiple processes and provides a conceptual anchor for the other criteria. We present the theoretical rationale for the construction and interpretation of each criterion. The assessment protocol and threat categories mirror those of the IUCN Red List of species. A trial of the protocol on terrestrial, subterranean, freshwater and marine ecosystems from around the world shows that its concepts are workable and its outcomes are robust, that required data are available, and that results are consistent with assessments carried out by local experts and authorities. The new protocol provides a consistent, practical and theoretically grounded framework for establishing a systematic Red List of the world’s ecosystems. This will complement the Red List of species and strengthen global capacity to report on and monitor the status of

Scientific foundations for an IUCN Red List of ecosystems.

Directory of Open Access Journals (Sweden)

David A Keith

Full Text Available An understanding of risks to biodiversity is needed for planning action to slow current rates of decline and secure ecosystem services for future human use. Although the IUCN Red List criteria provide an effective assessment protocol for species, a standard global assessment of risks to higher levels of biodiversity is currently limited. In 2008, IUCN initiated development of risk assessment criteria to support a global Red List of ecosystems. We present a new conceptual model for ecosystem risk assessment founded on a synthesis of relevant ecological theories. To support the model, we review key elements of ecosystem definition and introduce the concept of ecosystem collapse, an analogue of species extinction. The model identifies four distributional and functional symptoms of ecosystem risk as a basis for assessment criteria: A rates of decline in ecosystem distribution; B restricted distributions with continuing declines or threats; C rates of environmental (abiotic degradation; and D rates of disruption to biotic processes. A fifth criterion, E quantitative estimates of the risk of ecosystem collapse, enables integrated assessment of multiple processes and provides a conceptual anchor for the other criteria. We present the theoretical rationale for the construction and interpretation of each criterion. The assessment protocol and threat categories mirror those of the IUCN Red List of species. A trial of the protocol on terrestrial, subterranean, freshwater and marine ecosystems from around the world shows that its concepts are workable and its outcomes are robust, that required data are available, and that results are consistent with assessments carried out by local experts and authorities. The new protocol provides a consistent, practical and theoretically grounded framework for establishing a systematic Red List of the world's ecosystems. This will complement the Red List of species and strengthen global capacity to report on and monitor

Integrating landscape system and meta-ecosystem frameworks to advance the understanding of ecosystem function in heterogeneous landscapes: An analysis on the carbon fluxes in the Northern Highlands Lake District (NHLD) of Wisconsin and Michigan.

Science.gov (United States)

Yang, Haile; Chen, Jiakuan

2018-01-01

The successful integration of ecosystem ecology with landscape ecology would be conducive to understanding how landscapes function. There have been several attempts at this, with two main approaches: (1) an ecosystem-based approach, such as the meta-ecosystem framework and (2) a landscape-based approach, such as the landscape system framework. These two frameworks are currently disconnected. To integrate these two frameworks, we introduce a protocol, and then demonstrate application of the protocol using a case study. The protocol includes four steps: 1) delineating landscape systems; 2) classifying landscape systems; 3) adjusting landscape systems to meta-ecosystems and 4) integrating landscape system and meta-ecosystem frameworks through meta-ecosystems. The case study is the analyzing of the carbon fluxes in the Northern Highlands Lake District (NHLD) of Wisconsin and Michigan using this protocol. The application of this protocol revealed that one could follow this protocol to construct a meta-ecosystem and analyze it using the integrative framework of landscape system and meta-ecosystem frameworks. That is, one could (1) appropriately describe and analyze the spatial heterogeneity of the meta-ecosystem; (2) understand the emergent properties arising from spatial coupling of local ecosystems in the meta-ecosystem. In conclusion, this protocol is a useful approach for integrating the meta-ecosystem framework and the landscape system framework, which advances the describing and analyzing of the spatial heterogeneity and ecosystem function of interconnected ecosystems.

Role of small mammals in ecosystems

International Nuclear Information System (INIS)

Golley, F.B.

1978-01-01

Small mammals are one of the groups commonly studied as an ecological unit in ecosystem analysis; the aggregation being justified on taxonomic or methodological grounds. Since small mammals include animals with habits of herbivory, omnivory, and carnivory, nocturnal and diurnal habits, living in a great variety of habitats, and adapted to conditions of life such as burrowing and flight, the collection is a diverse taxonomic aggregation and an unusually bad ecological grouping. For ecosystem analysis, groupings of organisms that have evolved in common with each other in the community seem more reasonable than aggregations based on taxonomic grounds. The depth of the problem is made clear when we examine the record and find that there are almost no studies of energy and material flow in terrestrial food chains. It is incredible that almost every study of a population considers that population as a receiver and donor of energy and materials acting independently. It would appear that aggregation of food chains into ecosystem components might be more fruitful than aggregation of independent populations

Surface-based GPR underestimates below-stump root biomass

Science.gov (United States)

John R. Butnor; Lisa J. Samuelson; Thomas A. Stokes; Kurt H. Johnsen; Peter H. Anderson; Carlos A. Gonzalez-Benecke

2016-01-01

Aims While lateral root mass is readily detectable with ground penetrating radar (GPR), the roots beneath a tree (below-stump) and overlapping lateral roots near large trees are problematic for surface-based antennas operated in reflection mode. We sought to determine if tree size (DBH) effects GPR root detection proximal to longleaf pine (Pinus palustris Mill) and if...

Changes in biodiversity and ecosystem function during the restoration of a tropical forest in south China

Institute of Scientific and Technical Information of China (English)

REN Hai; LI ZhiAn; SHEN WeiJun; YU ZuoYue; PENG ShaoLin; LIAO ChongHui; DING MingMao; WU JianGuo

2007-01-01

Tropical forests continue to vanish rapidly, but few long-term studies have ever examined if and how the lost forests can be restored. Based on a 45-year restoration study in south China, we found that a tropical rain forest, once completely destroyed, could not recover naturally without deliberate restoration efforts. We identified two kinds of thresholds that must be overcome with human ameliorative measures before the ecosystem was able to recover. The first threshold was imposed primarily by extreme physical conditions such as exceedingly high surface temperature and impoverished soil, while the second was characterized by a critical level of biodiversity and a landscape context that accommodates dispersal and colonization processes. Our three treatment catchments (un-restored barren land, single-species plantation, and mixed-forest stand) exhibited dramatically different changes in biodiversity and ecosystem functioning over 4 decades. The mixed forest, having the highest level of biodiversity and ecosystem functioning, possesses several major properties of tropical rain forest.These findings may have important implications for the restoration of many severely degraded or lost tropical forest ecosystems.

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.

The role of recurrent disturbances for ecosystem multifunctionality.

Science.gov (United States)

Villnäs, Anna; Norkko, Joanna; Hietanen, Susanna; Josefson, Alf B; Lukkari, Kaarina; Norkko, Alf

2013-10-01

Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in response to repetitive pulse disturbances. The degradation in overall ecosystem functioning was, however, evident at an earlier stage than for single ecosystem functions and was induced after a short pulse of hypoxia (i.e., three days), which likely reduced ecosystem resistance to further hypoxic perturbations. The increasing number of repeated pulse disturbances gradually moved the system closer to a press response. In addition to the disturbance regime, the changes in benthic trait composition as well as habitat heterogeneity were important for explaining the variability in overall ecosystem functioning. Our results suggest that disturbance-induced responses across multiple ecosystem functions can serve as a warning signal for losses of the adaptive capacity of an ecosystem, and might at an early stage provide information to managers and policy makers when remediation efforts should be initiated.

Species-Specific Effects on Ecosystem Functioning Can Be Altered by Interspecific Interactions.

Science.gov (United States)

Clare, David S; Spencer, Matthew; Robinson, Leonie A; Frid, Christopher L J

2016-01-01

Biological assemblages are constantly undergoing change, with species being introduced, extirpated and experiencing shifts in their densities. Theory and experimentation suggest that the impacts of such change on ecosystem functioning should be predictable based on the biological traits of the species involved. However, interspecific interactions could alter how species affect functioning, with the strength and sign of interactions potentially depending on environmental context (e.g. homogenous vs. heterogeneous conditions) and the function considered. Here, we assessed how concurrent changes to the densities of two common marine benthic invertebrates, Corophium volutator and Hediste diversicolor, affected the ecological functions of organic matter consumption and benthic-pelagic nutrient flux. Complementary experiments were conducted within homogenous laboratory microcosms and naturally heterogeneous field plots. When the densities of the species were increased within microcosms, interspecific interactions enhanced effects on organic matter consumption and reduced effects on nutrient flux. Trait-based predictions of how each species would affect functioning were only consistently supported when the density of the other species was low. In field plots, increasing the density of either species had a positive effect on organic matter consumption (with no significant interspecific interactions) but no effect on nutrient flux. Our results indicate that species-specific effects on ecosystem functioning can be altered by interspecific interactions, which can be either facilitative (positive) or antagonistic (negative) depending on the function considered. The impacts of biodiversity change may therefore not be predictable based solely on the biological traits of the species involved. Possible explanations for why interactions were detected in microcosms but not in the field are discussed.

Species-Specific Effects on Ecosystem Functioning Can Be Altered by Interspecific Interactions.

Directory of Open Access Journals (Sweden)

David S Clare

Full Text Available Biological assemblages are constantly undergoing change, with species being introduced, extirpated and experiencing shifts in their densities. Theory and experimentation suggest that the impacts of such change on ecosystem functioning should be predictable based on the biological traits of the species involved. However, interspecific interactions could alter how species affect functioning, with the strength and sign of interactions potentially depending on environmental context (e.g. homogenous vs. heterogeneous conditions and the function considered. Here, we assessed how concurrent changes to the densities of two common marine benthic invertebrates, Corophium volutator and Hediste diversicolor, affected the ecological functions of organic matter consumption and benthic-pelagic nutrient flux. Complementary experiments were conducted within homogenous laboratory microcosms and naturally heterogeneous field plots. When the densities of the species were increased within microcosms, interspecific interactions enhanced effects on organic matter consumption and reduced effects on nutrient flux. Trait-based predictions of how each species would affect functioning were only consistently supported when the density of the other species was low. In field plots, increasing the density of either species had a positive effect on organic matter consumption (with no significant interspecific interactions but no effect on nutrient flux. Our results indicate that species-specific effects on ecosystem functioning can be altered by interspecific interactions, which can be either facilitative (positive or antagonistic (negative depending on the function considered. The impacts of biodiversity change may therefore not be predictable based solely on the biological traits of the species involved. Possible explanations for why interactions were detected in microcosms but not in the field are discussed.

The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world.

Science.gov (United States)

Griffiths, Jennifer R; Kadin, Martina; Nascimento, Francisco J A; Tamelander, Tobias; Törnroos, Anna; Bonaglia, Stefano; Bonsdorff, Erik; Brüchert, Volker; Gårdmark, Anna; Järnström, Marie; Kotta, Jonne; Lindegren, Martin; Nordström, Marie C; Norkko, Alf; Olsson, Jens; Weigel, Benjamin; Žydelis, Ramunas; Blenckner, Thorsten; Niiranen, Susa; Winder, Monika

2017-06-01

Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems, and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure and function are strongly affected by anthropogenic pressures; however, there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic-pelagic coupling processes (e.g., nutrient exchange and sedimentation of organic material) are to some extent quantifiable, but the magnitude and variability of biological processes are rarely assessed, preventing quantitative comparisons. Changing oxygen conditions will continue to have widespread effects on the processes that govern inorganic and organic matter exchange among habitats while climate change and nutrient load reductions may have large effects on organic matter sedimentation. Many biological processes (predation, bioturbation) are expected to be sensitive to anthropogenic drivers, but the outcomes for ecosystem function are largely unknown. We emphasize how improved empirical and experimental understanding of benthic-pelagic coupling processes and their variability are necessary to inform models that can quantify the feedbacks among processes and ecosystem responses to a changing world. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

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. PMID:27828969

Defining ecosystem assets for natural capital accounting

Science.gov (United States)

Hein, Lars; Bagstad, Kenneth J.; 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.

Predicting Plant-Accessible Water in the Critical Zone: Mountain Ecosystems in a Mediterranean Climate

Science.gov (United States)

Klos, P. Z.; Goulden, M.; Riebe, C. S.; Tague, C.; O'Geen, A. T.; Flinchum, B. A.; Safeeq, M.; Conklin, M. H.; Hart, S. C.; Asefaw Berhe, A.; Hartsough, P. C.; Holbrook, S.; Bales, R. C.

2017-12-01

Enhanced understanding of subsurface water storage, and the below-ground architecture and processes that create it, will advance our ability to predict how the impacts of climate change - including drought, forest mortality, wildland fire, and strained water security - will take form in the decades to come. Previous research has examined the importance of plant-accessible water in soil, but in upland landscapes within Mediterranean climates the soil is often only the upper extent of subsurface water storage. We draw insights from both this previous research and a case study of the Southern Sierra Critical Zone Observatory to: define attributes of subsurface storage, review observed patterns in its distribution, highlight nested methods for its estimation across scales, and showcase the fundamental processes controlling its formation. We observe that forest ecosystems at our sites subsist on lasting plant-accessible stores of subsurface water during the summer dry period and during multi-year droughts. This indicates that trees in these forest ecosystems are rooted deeply in the weathered, highly porous saprolite, which reaches up to 10-20 m beneath the surface. This confirms the importance of large volumes of subsurface water in supporting ecosystem resistance to climate and landscape change across a range of spatiotemporal scales. This research enhances the ability to predict the extent of deep subsurface storage across landscapes; aiding in the advancement of both critical zone science and the management of natural resources emanating from similar mountain ecosystems worldwide.

Ecosystem services: developing sustainable management paradigms based on wetland functions and processes

Science.gov (United States)

Euliss, Ned H.; Mushet, David M.; Smith, Loren M.; Conner, William H.; Burkett, Virginia R.; Wilcox, Douglas A.; Hester, Mark W.; Zheng, Haochi

2013-01-01

In the late nineteenth century and twentieth century, there was considerable interest and activity to develop the United States for agricultural, mining, and many other purposes to improve the quality of human life standards and prosperity. Most of the work to support this development was focused along disciplinary lines with little attention focused on ecosystem service trade-offs or synergisms, especially those that transcended boundaries of scientific disciplines and specific interest groups. Concurrently, human population size has increased substantially and its use of ecosystem services has increased more than five-fold over just the past century. Consequently, the contemporary landscape has been highly modified for human use, leaving behind a fragmented landscape where basic ecosystem functions and processes have been broadly altered. Over this period, climate change also interacted with other anthropogenic effects, resulting in modern environmental problems having a complexity that is without historical precedent. The challenge before the scientific community is to develop new science paradigms that integrate relevant scientific disciplines to properly frame and evaluate modern environmental problems in a systems-type approach to better inform the decision-making process. Wetland science is a relatively new discipline that grew out of the conservation movement of the early twentieth century. In the United States, most of the conservation attention in the earlier days was on wildlife, but a growing human awareness of the importance of the environment led to the passage of the National Environmental Policy Act in 1969. Concurrently, there was a broadening interest in conservation science, and the scientific study of wetlands gradually gained acceptance as a scientific discipline. Pioneering wetland scientists became formally organized when they formed The Society of Wetland Scientists in 1980 and established a publication outlet to share wetland research

Dynamics of arbuscular mycorrhizal fungal community structure and functioning along a nitrogen enrichment gradient in an alpine meadow ecosystem.

Science.gov (United States)

Jiang, Shengjing; Liu, Yongjun; Luo, Jiajia; Qin, Mingsen; Johnson, Nancy Collins; Öpik, Maarja; Vasar, Martti; Chai, Yuxing; Zhou, Xiaolong; Mao, Lin; Du, Guozhen; An, Lizhe; Feng, Huyuan

2018-03-30

Nitrogen (N) availability is increasing dramatically in many ecosystems, but the influence of elevated N on the functioning of arbuscular mycorrhizal (AM) fungi in natural ecosystems is not well understood. We measured AM fungal community structure and mycorrhizal function simultaneously across an experimental N addition gradient in an alpine meadow that is limited by N but not by phosphorus (P). AM fungal communities at both whole-plant-community (mixed roots) and single-plant-species (Elymus nutans roots) scales were described using pyro-sequencing, and the mycorrhizal functioning was quantified using a mycorrhizal-suppression treatment in the field (whole-plant-community scale) and a glasshouse inoculation experiment (single-plant-species scale). Nitrogen enrichment progressively reduced AM fungal abundance, changed AM fungal community composition, and shifted mycorrhizal functioning towards parasitism at both whole-plant-community and E. nutans scales. N-induced shifts in AM fungal community composition were tightly linked to soil N availability and/or plant species richness, whereas the shifts in mycorrhizal function were associated with the communities of specific AM fungal lineages. The observed changes in both AM fungal community structure and functioning across an N enrichment gradient highlight that N enrichment of ecosystems that are not P-limited can induce parasitic mycorrhizal functioning and influence plant community structure and ecosystem sustainability. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Exact ground-state correlation functions of one-dimenisonal strongly correlated electron models with resonating-valence-bond ground state

International Nuclear Information System (INIS)

Yamanaka, Masanori; Honjo, Shinsuke; Kohmoto, Mahito

1996-01-01

We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing

Ecosystem carbon density and allocation across a chronosequence of longleaf pine forests.

Science.gov (United States)

Samuelson, Lisa J; Stokes, Thomas A; Butnor, John R; Johnsen, Kurt H; Gonzalez-Benecke, Carlos A; Martin, Timothy A; Cropper, Wendell P; Anderson, Pete H; Ramirez, Michael R; Lewis, John C

2017-01-01

Forests can partially offset greenhouse gas emissions and contribute to climate change mitigation, mainly through increases in live biomass. We quantified carbon (C) density in 20 managed longleaf pine (Pinus palustris Mill.) forests ranging in age from 5 to 118 years located across the southeastern United States and estimated above- and belowground C trajectories. Ecosystem C stock (all pools including soil C) and aboveground live tree C increased nonlinearly with stand age and the modeled asymptotic maxima were 168 Mg C/ha and 80 Mg C/ha, respectively. Accumulation of ecosystem C with stand age was driven mainly by increases in aboveground live tree C, which ranged from ecosystem C. Live root C (sum of below-stump C, ground penetrating radar measurement of lateral root C, and live fine root C) increased with stand age and represented 4-22% of ecosystem C. Soil C was related to site index, but not to stand age, and made up 39-92% of ecosystem C. Live understory C, forest floor C, downed dead wood C, and standing dead wood C were small fractions of ecosystem C in these frequently burned stands. Stand age and site index accounted for 76% of the variation in ecosystem C among stands. The mean root-to-shoot ratio calculated as the average across all stands (excluding the grass-stage stand) was 0.54 (standard deviation of 0.19) and higher than reports for other conifers. Long-term accumulation of live tree C, combined with the larger role of belowground accumulation of lateral root C than in other forest types, indicates a role of longleaf pine forests in providing disturbance-resistant C storage that can balance the more rapid C accumulation and C removal associated with more intensively managed forests. Although other managed southern pine systems sequester more C over the short-term, we suggest that longleaf pine forests can play a meaningful role in regional forest C management. © 2016 by the Ecological Society of America.

Ambient Noise Green's Function Simulation of Long-Period Ground Motions for Reverse Faulting

Science.gov (United States)

Miyake, H.; Beroza, G. C.

2009-12-01

Long-time correlation of ambient seismic noise has been demonstrated as a useful tool for strong ground motion prediction [Prieto and Beroza, 2008]. An important advantage of ambient noise Green's functions is that they can be used for ground motion simulation without resorting to either complex 3-D velocity structure to develop theoretical Green’s functions, or aftershock records for empirical Green’s function analysis. The station-to-station approach inherent to ambient noise Green’s functions imposes some limits to its application, since they are band-limited, applied at the surface, and for a single force. We explore the applicability of this method to strong motion prediction using the 2007 Chuetsu-oki, Japan, earthquake (Mw 6.6, depth = 9 km), which excited long-period ground motions in and around the Kanto basin almost 200 km from the epicenter. We test the performance of ambient noise Green's function for long-period ground motion simulation. We use three components of F-net broadband data at KZK station, which is located near the source region, as a virtual source, and three components of six F-net stations in and around the Kanto basin to calculate the response. An advantage to applying this approach in Japan is that ambient-noise sources are active in diverse directions. The dominant period of the ambient noise for the F-net datasets is mostly 7 s over the year, and amplitudes are largest in winter. This period matches the dominant periods of the Kanto and Niigata basins. For the 9 components of the ambient noise Green’s functions, we have confirmed long-period components corresponding to Love wave and Rayleigh waves that can be used for simulation of the 2007 Chuetsu-oki earthquake. The relative amplitudes, phases, and durations of the ambient noise Green’s functions at the F-net stations in and around the Kanto basin respect to F-net KZK station are fairly well matched with those of the observed ground motions for the 2007 Chuetsu

Dimensions of ecosystem theory

International Nuclear Information System (INIS)

O'Neill, R.V.; Reichle, D.E.

1979-01-01

Various dimensions of ecosystem structure and behavior that seem to develop from the ubiquitous phenomena of system growth and persistence were studied. While growth and persistence attributes of ecosystems may appear to be simplistic phenomena upon which to base a comprehensive ecosystem theory, these same attributes have been fundamental to the theoretical development of other biological disciplines. These attributes were explored at a hierarchical level in a self-organizing system, and adaptive system strategies that result were analyzed. Previously developed causative relations (Reichle et al., 1975c) were examined, their theoretical implications expounded upon, and the assumptions tested with data from a variety of forest types. The conclusions are not a theory in themselves, but a state of organization of concepts contributing towards a unifying theory, along the lines promulgated by Bray (1958). The inferences drawn rely heavily upon data from forested ecosystems of the world, and have yet to be validated against data from a much more diverse range of ecosystem types. Not all of the interpretations are logically tight - there is room for other explanations, which it is hoped will provide fruitful grounds for further speculation

Context-Specific Trophic and Functional Ecology of Fishes of Small Stream Ecosystems in the Ouachita National Forest

Science.gov (United States)

William J. Matthews; A. Maria Miller-Lemke; Melvin L. Warren; Donna Cobb; Jeffery G. Stewart; Betty Crump; Frances P. Gelwick

2004-01-01

Abstract - Fish play diverse and important roles in stream ecosystems, but details about ecosystem effects are poorly known for many freshwater fish species. A requisite first step to understanding functional roles of individual species is information on their trophic ecology in the context of particular environmental settings. Stomach contents were...

Faunal impact on vegetation structure and ecosystem function in mangrove forests: A review

DEFF Research Database (Denmark)

Cannicci, S.; Burows, D.; Fratini, S.

2008-01-01

The last 20 years witnessed a real paradigm shift concerning the impact of biotic factors on ecosystem functions as well as on vegetation structure of mangrove forests. Before this small scientific revolution took place, structural aspects of mangrove forests were viewed to be the result of abiotic...... processes acting from the bottom-up, while, at ecosystem level, the outwelling hypothesis stated that mangroves primary production was removed via tidal action and carried to adjacent nearshore ecosystems where it fuelled detrital based food-webs. The sesarmid crabs were the first macrofaunal taxon...... to be considered a main actor in mangrove structuring processes, thanks to a number of studies carried out in the Indo-Pacific forests in the late 1970s and early 1980s. Following these classical papers, a number of studies on Sesarmidae feeding and burrowing ecology were carried out, which leave no doubts about...

Linking the spatial patterns of organisms and abiotic factors to ecosystem function and management: insights from semi-arid environments

Directory of Open Access Journals (Sweden)

F. T. Maestre

2006-12-01

Full Text Available Numerous theoretical and modeling studies have demonstrated the ecological significance of the spatial patterning of organisms on ecosystem functioning and dynamics. However, there is a paucity of empirical evidence that quantitatively shows how changes in the spatial patterns of the organisms forming biotic communities are directly related to ecosystem structure and functioning. In this article, I review a series of experiments and observational studies conducted in semi-arid environments from Spain (degraded calcareous shrubland, steppes dominated by Stipa tenacissima, and gypsum shrublands to: 1 evaluate whether the spatial patterns of the dominant biotic elements in the community are linked to ecosystem structure and functioning, and 2 test if these patterns, and those of abiotic factors, can be used to improve ecosystem restoration. In the semiarid steppes we found a significant positive relationship between the spatial pattern of the perennial plant community and: i the water status of S. tenacissima and ii perennial species richness and diversity. Experimental plantings conducted in these steppes showed that S. tenacissima facilitated the establishment of shrub seedlings, albeit the magnitude and direction of this effect was dependent on rainfall conditions during the first yr after planting. In the gypsum shrubland, a significant, direct relationship between the spatial pattern of the biological soil crusts and surrogates of ecosystem functioning (soil bulk density and respiration was found. In a degraded shrubland with very low vegetation cover, the survival of an introduced population of the shrub Pistacia lentiscus showed marked spatial patterns, which were related to the spatial patterns of soil properties such as soil compaction and sand content. These results provide empirical evidence on the importance of spatial patterns for maintaining ecosystem structure and functioning in semi-arid ecosystems

Development of a data driven process-based model for remote sensing of terrestrial ecosystem productivity, evapotranspiration, and above-ground biomass

Science.gov (United States)

El Masri, Bassil

2011-12-01

Modeling terrestrial ecosystem functions and structure has been a subject of increasing interest because of the importance of the terrestrial carbon cycle in global carbon budget and climate change. In this study, satellite data were used to estimate gross primary production (GPP), evapotranspiration (ET) for two deciduous forests: Morgan Monroe State forest (MMSF) in Indiana and Harvard forest in Massachusetts. Also, above-ground biomass (AGB) was estimated for the MMSF and the Howland forest (mixed forest) in Maine. Surface reflectance and temperature, vegetation indices, soil moisture, tree height and canopy area derived from the Moderate Resolution Imagining Spectroradiometer (MODIS), the Advanced Microwave Scanning Radiometer (AMRS-E), LIDAR, and aerial imagery respectively, were used for this purpose. These variables along with others derived from remotely sensed data were used as inputs variables to process-based models which estimated GPP and ET and to a regression model which estimated AGB. The process-based models were BIOME-BGC and the Penman-Monteith equation. Measured values for the carbon and water fluxes obtained from the Eddy covariance flux tower were compared to the modeled GPP and ET. The data driven methods produced good estimation of GPP and ET with an average root mean square error (RMSE) of 0.17 molC/m2 and 0.40 mm/day, respectively for the MMSF and the Harvard forest. In addition, allometric data for the MMSF were used to develop the regression model relating AGB with stem volume. The performance of the AGB regression model was compared to site measurements using remotely sensed data for the MMSF and the Howland forest where the model AGB RMSE ranged between 2.92--3.30 Kg C/m2. Sensitivity analysis revealed that improvement in maintenance respiration estimation and remotely sensed maximum photosynthetic activity as well as accurate estimate of canopy resistance will result in improved GPP and ET predictions. Moreover, AGB estimates were

Calibration of two complex ecosystem models with different likelihood functions

Science.gov (United States)

Hidy, Dóra; Haszpra, László; Pintér, Krisztina; Nagy, Zoltán; Barcza, Zoltán

2014-05-01

The biosphere is a sensitive carbon reservoir. Terrestrial ecosystems were approximately carbon neutral during the past centuries, but they became net carbon sinks due to climate change induced environmental change and associated CO2 fertilization effect of the atmosphere. Model studies and measurements indicate that the biospheric carbon sink can saturate in the future due to ongoing climate change which can act as a positive feedback. Robustness of carbon cycle models is a key issue when trying to choose the appropriate model for decision support. The input parameters of the process-based models are decisive regarding the model output. At the same time there are several input parameters for which accurate values are hard to obtain directly from experiments or no local measurements are available. Due to the uncertainty associated with the unknown model parameters significant bias can be experienced if the model is used to simulate the carbon and nitrogen cycle components of different ecosystems. In order to improve model performance the unknown model parameters has to be estimated. We developed a multi-objective, two-step calibration method based on Bayesian approach in order to estimate the unknown parameters of PaSim and Biome-BGC models. Biome-BGC and PaSim are a widely used biogeochemical models that simulate the storage and flux of water, carbon, and nitrogen between the ecosystem and the atmosphere, and within the components of the terrestrial ecosystems (in this research the developed version of Biome-BGC is used which is referred as BBGC MuSo). Both models were calibrated regardless the simulated processes and type of model parameters. The calibration procedure is based on the comparison of measured data with simulated results via calculating a likelihood function (degree of goodness-of-fit between simulated and measured data). In our research different likelihood function formulations were used in order to examine the effect of the different model

Structure, functioning, and cumulative stressors of Mediterranean deep-sea ecosystems

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Tecchio, Samuele; Coll, Marta; Sardà, Francisco

2015-06-01

Environmental stressors, such as climate fluctuations, and anthropogenic stressors, such as fishing, are of major concern for the management of deep-sea ecosystems. Deep-water habitats are limited by primary productivity and are mainly dependent on the vertical input of organic matter from the surface. Global change over the latest decades is imparting variations in primary productivity levels across oceans, and thus it has an impact on the amount of organic matter landing on the deep seafloor. In addition, anthropogenic impacts are now reaching the deep ocean. The Mediterranean Sea, the largest enclosed basin on the planet, is not an exception. However, ecosystem-level studies of response to varying food input and anthropogenic stressors on deep-sea ecosystems are still scant. We present here a comparative ecological network analysis of three food webs of the deep Mediterranean Sea, with contrasting trophic structure. After modelling the flows of these food webs with the Ecopath with Ecosim approach, we compared indicators of network structure and functioning. We then developed temporal dynamic simulations varying the organic matter input to evaluate its potential effect. Results show that, following the west-to-east gradient in the Mediterranean Sea of marine snow input, organic matter recycling increases, net production decreases to negative values and trophic organisation is overall reduced. The levels of food-web activity followed the gradient of organic matter availability at the seafloor, confirming that deep-water ecosystems directly depend on marine snow and are therefore influenced by variations of energy input, such as climate-driven changes. In addition, simulations of varying marine snow arrival at the seafloor, combined with the hypothesis of a possible fishery expansion on the lower continental slope in the western basin, evidence that the trawling fishery may pose an impact which could be an order of magnitude stronger than a climate

Power and limitation of soil properties as predictors of rangeland health and ecosystem functioning in a Northern mixed-grass prairie[Abstract

Science.gov (United States)

Soil properties are thought to affect rangeland ecosystem functioning (e.g. primary productivity, hydrology), and thus soil variables that are consistently correlated with key ecosystem functions may be general indicators of rangeland health. We summarize results from several studies in mixed-grass...

Fine Scale ANUClimate Data for Ecosystem Modeling and Assessment of Plant Functional Types

Science.gov (United States)

Hutchinson, M. F.; Kesteven, J. L.; Xu, T.; Evans, B. J.; Togashi, H. F.; Stein, J. L.

2015-12-01

High resolution spatially extended values of climate variables play a central role in the assessment of climate and projected future climate in ecosystem modeling. The ground based meteorological network remains a key resource for deriving these spatially extended climate variables. We report on the production, and applications, of new anomaly based fine scale spatial interpolations of key climate variables at daily and monthly time scale, across the Australian continent. The methods incorporate several innovations that have significantly improved spatial predictive accuracy, as well as providing a platform for the incorporation of additional remotely sensed data. The interpolated climate data are supporting many continent-wide ecosystem modeling applications and are playing a key role in testing optimality hypotheses associated with plant functional types (PFTs). The accuracy, and robustness to data error, of anomaly-based interpolation has been enhanced by incorporating physical process aspects of the different climate variables and employing robust statistical methods implemented in the ANUSPLIN package. New regression procedures have also been developed to estimate "background" monthly climate normals from all stations with minimal records to substantially increase the density of supporting spatial networks. Monthly mean temperature interpolation has been enhanced by incorporating process based coastal effects that have reduced predictive error by around 10%. Overall errors in interpolated monthly temperature fields are around 25% less than errors reported by an earlier study. For monthly and daily precipitation, a new anomaly structure has been devised to take account of the skewness in precipitation data and the large proportion of zero values that present significant challenges to standard interpolation methods. The many applications include continent-wide Gross Primary Production modeling and assessing constraints on light and water use efficiency derived

Effects of ice storm on forest ecosystem of southern China in 2008 Shaoqiang Wang1, Lei Zhou1, Weimin Ju2, Kun Huang1 1Key Lab of Ecosystem Network Observation and Modeling, Institute of Geographical Sciences and Natural Resources Research, Beijing, 10010

Science.gov (United States)

Wang, Shaoqiang

2014-05-01

Evidence is mounting that an increase in extreme climate events has begun to occur worldwide during the recent decades, which affect biosphere function and biodiversity. Ecosystems returned to its original structures and functions to maintain its sustainability, which was closely dependent on ecosystem resilience. Understanding the resilience and recovery capacity of ecosystem to extreme climate events is essential to predicting future ecosystem responses to climate change. Given the overwhelming importance of this region in the overall carbon cycle of forest ecosystems in China, south China suffered a destructive ice storm in 2008. In this study, we used the number of freezing day and a process-based model (Boreal Ecosystem Productivity Simulator, BEPS) to characterize the spatial distribution of ice storm region in southeastern China and explore the impacts on carbon cycle of forest ecosystem over the past decade. The ecosystem variables, i.e. Net primary productivity (NPP), Evapotranspiration (ET), and Water use efficiency (WUE, the ratio of NPP to ET) from the outputs of BEPS models were used to detect the resistance and resilience of forest ecosystem in southern China. The pattern of ice storm-induced forest productivity widespread decline was closely related to the number of freezing day during the ice storm period. The NPP of forest area suffered heavy ice storm returned to normal status after five months with high temperature and ample moisture, indicated a high resilience of subtropical forest in China. The long-term changes of forest WUE remain stable, behaving an inherent sensitivity of ecosystem to extreme climate events. In addition, ground visits suggested that the recovery of forest productivity was attributed to rapid growth of understory. Understanding the variability and recovery threshold of ecosystem following extreme climate events help us to better simulate and predict the variability of ecosystem structure and function under current and

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...

Are there links between responses of soil microbes and ecosystem functioning to elevated CO2, N deposition and warming? A global perspective.

Science.gov (United States)

García-Palacios, Pablo; Vandegehuchte, Martijn L; Shaw, E Ashley; Dam, Marie; Post, Keith H; Ramirez, Kelly S; Sylvain, Zachary A; de Tomasel, Cecilia Milano; Wall, Diana H

2015-04-01

In recent years, there has been an increase in research to understand how global changes' impacts on soil biota translate into altered ecosystem functioning. However, results vary between global change effects, soil taxa, and ecosystem processes studied, and a synthesis of relationships is lacking. Therefore, here we initiate such a synthesis to assess whether the effect size of global change drivers (elevated CO2, N deposition, and warming) on soil microbial abundance is related with the effect size of these drivers on ecosystem functioning (plant biomass, soil C cycle, and soil N cycle) using meta-analysis and structural equation modeling. For N deposition and warming, the global change effect size on soil microbes was positively associated with the global change effect size on ecosystem functioning, and these relationships were consistent across taxa and ecosystem processes. However, for elevated CO2, such links were more taxon and ecosystem process specific. For example, fungal abundance responses to elevated CO2 were positively correlated with those of plant biomass but negatively with those of the N cycle. Our results go beyond previous assessments of the sensitivity of soil microbes and ecosystem processes to global change, and demonstrate the existence of general links between the responses of soil microbial abundance and ecosystem functioning. Further we identify critical areas for future research, specifically altered precipitation, soil fauna, soil community composition, and litter decomposition, that are need to better quantify the ecosystem consequences of global change impacts on soil biodiversity. © 2014 John Wiley & Sons Ltd.

The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world

DEFF Research Database (Denmark)

Griffiths, Jennifer R.; Kadin, Martina; Nascimento, Francisco J. A.

2017-01-01

and function is strongly affected by anthropogenic pressures, however there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling...... processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study, and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic......Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure...

The meaning of functional trait composition of food webs for ecosystem functioning.

Science.gov (United States)

Gravel, Dominique; Albouy, Camille; Thuiller, Wilfried

2016-05-19

There is a growing interest in using trait-based approaches to characterize the functional structure of animal communities. Quantitative methods have been derived mostly for plant ecology, but it is now common to characterize the functional composition of various systems such as soils, coral reefs, pelagic food webs or terrestrial vertebrate communities. With the ever-increasing availability of distribution and trait data, a quantitative method to represent the different roles of animals in a community promise to find generalities that will facilitate cross-system comparisons. There is, however, currently no theory relating the functional composition of food webs to their dynamics and properties. The intuitive interpretation that more functional diversity leads to higher resource exploitation and better ecosystem functioning was brought from plant ecology and does not apply readily to food webs. Here we appraise whether there are interpretable metrics to describe the functional composition of food webs that could foster a better understanding of their structure and functioning. We first distinguish the various roles that traits have on food web topology, resource extraction (bottom-up effects), trophic regulation (top-down effects), and the ability to keep energy and materials within the community. We then discuss positive effects of functional trait diversity on food webs, such as niche construction and bottom-up effects. We follow with a discussion on the negative effects of functional diversity, such as enhanced competition (both exploitation and apparent) and top-down control. Our review reveals that most of our current understanding of the impact of functional trait diversity on food web properties and functioning comes from an over-simplistic representation of network structure with well-defined levels. We, therefore, conclude with propositions for new research avenues for both theoreticians and empiricists. © 2016 The Author(s).

Impact of soil moisture deficit on ecosystem function across the United States

Science.gov (United States)

Susan Moran; Morgan Ross; Mallory Burns

2016-01-01

The cumulative effect of recent prolonged warm drought on regional ecosystem function is still uncertain. Large regions of the United States are experiencing new hydroclimatic conditions with extreme variability in climate drivers such as total precipitation, precipitation patterns (e.g., storm size, intensity and frequency), and seasonal temperatures.

Effect of land use change on ecosystem function of dung beetles: experimental evidence from Wallacea Region in Sulawesi, Indonesia

Directory of Open Access Journals (Sweden)

SHAHABUDDIN

2011-07-01

Full Text Available Shahabuddin (2011 Effect of land use change on ecosystem function of dung beetles: experimental evidence from Wallacea Region in Sulawesi, Indonesia. Biodiversitas 12: 177-181. The deforestation of tropical forests and their subsequent conversion to human-dominated land-use systems is one of the most significant causes of biodiversity loss. However clear understanding of the links between ecological functions and biodiversity is needed to evaluate and predict the true environmental consequences of human activities. This study provided experimental evidence comparing ecosystem function of dung beetles across a land use gradient ranging from natural tropical forest and agroforestry systems to open cultivated areas in Central Sulawesi. Therefore, standardized dung pats were exposed at each land-use type to assess dung removal and parasite suppression activity by dung beetles. The results showed that ecosystem function of dung beetles especially dung burial activity were remarkably disrupted by land use changes from natural forest to open agricultural area. Dung beetles presence enhanced about 53% of the total dung removed and reduced about 83% and 63% of fly population and species number respectively, indicating a pronounce contribution of dung beetles in our ecosystem.

Resuscitation of the rare biosphere contributes to pulses of ecosystem activity

Directory of Open Access Journals (Sweden)

Zach eAanderud

2015-01-01

Full Text Available Dormancy is a life history trait that may have important implications for linking microbial communities to the functioning of natural and managed ecosystems. Rapid changes in environmental cues may resuscitate dormant bacteria and create pulses of ecosystem activity. In this study, we used heavy-water (H218O stable isotope probing (SIP to identify fast-growing bacteria that were associated with pulses of trace gases (CO2, CH4, and N2O from different ecosystems (agricultural site, grassland, deciduous forest, and coniferous forest following a soil-rewetting event. Irrespective of ecosystem type, a large fraction (69 - 74% of the bacteria that responded to rewetting were below detection limits in the dry soils. Based on the recovery of sequences, in just a few days, hundreds of rare taxa increased in abundance and in some cases became dominant members of the rewetted communities, especially bacteria belonging to the Sphingomonadaceae, Comamonadaceae, and Oxalobacteraceae. Resuscitation led to dynamic shifts in the rank abundance of taxa that caused previously rare bacteria to comprise nearly 60% of the sequences that were recovered in rewetted communities. This rapid turnover of the bacterial community corresponded with a 5 20 fold increase in the net production of CO2 and up to a 150% reduction in the net production of CH4 from rewetted soils. Results from our study demonstrate that the rare biosphere may account for a large and dynamic fraction of a community that is important for the maintenance of bacterial biodiversity. Moreover, our findings suggest that the resuscitation of rare taxa from seed banks contribute to ecosystem functioning.

The role of recurrent disturbances for ecosystem multifunctionality

OpenAIRE

Villnäs, Anna; Norkko, Joanna; Hietanen, Susanna; Josefson, Alf; Lukkari, Kaarina; Norkko, Alf

2013-01-01

Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in respons...

Belowground dynamics in mangrove ecosystems

Science.gov (United States)

McKee, Karen L.

2004-01-01

Mangrove ecosystems are tropical/subtropical communities of primarily tree species that grow in the intertidal zone. These tidal communities are important coastal ecosystems that are valued for a variety of ecological and societal goods and services (fig. 1). Mangrove wetlands are important filters of materials moving between the land and sea, trapping sediment, nutrients, and pollutants in runoff from uplands and preventing their direct introduction into sensitive marine ecosystems such as seagrass beds and coral reefs. Mangroves serve as nursery grounds and refuge for a variety of organisms and are consequently vital to the biological productivity of coastal waters. Furthermore, because mangroves are highly resilient to disturbances such as hurricanes, they represent a self-sustaining, protective barrier for human populations living in the coastal zone. Mangrove ecosystems also contribute to shoreline stabilization through consolidation of unstable mineral sediments and peat formation. In order to help conserve mangrove ecoystems, scientists with the United States Geological Survey (USGS) at the National Wetlands Research Center are working to more fully understand the dynamics that impact these vital ecosystems.

From Ecosystem-Scale to Litter Biochemistry: Controls on Carbon Sequestration in Coastal Wetlands of the Western Gulf of Mexico

Science.gov (United States)

Louchouarn, P.; Kaiser, K.; Norwood, M. J.; Sterne, A. M. E.; Armitage, A. R.; HighField, W.; Brody, S.

2015-12-01

Landscape-level shifts in plant species distribution and abundance can fundamentally change the structure and services of an ecosystem. Such shifts are occurring within mangrove-marsh ecotones of the U.S., where over the last few decades, relatively mild winters have led to mangrove expansion into areas previously occupied by salt marsh plants. Here we present the synthesis of 3 years of multidisciplinary work to quantify ecosystem shifts at the regional scale, along the entire Texas (USA) coast of the western Gulf of Mexico, and transcribe these shifts into carbon (C) sequestration mass balances. We classified Landsat-5 Thematic Mapper images using artificial neural networks to quantify shifts in areal coverage of black mangrove (Avicennia germinans) and salt marsh (Spartina alterniflora and other grass and forb species) over 20 years across the Texas Gulf coast. Between 1990 and 2010, mangrove area expanded by 74% (+16 km2). Concurrently, salt marsh area experienced a net loss of 24% (-78 km2). Most of that loss was due to conversion to tidal flats or water, likely a result of relative sea level rise, with only 6% attributable to mangrove expansion. Although relative carbon load (per surface area) are statistically larger for mangrove wetlands, total C loads are larger for salt marsh wetlands due to their greater aerial coverage. The entire loss of above ground C (~7.0·109 g), was offset by salt marsh expansion (2.0·109 g) and mangrove expansion (5.6·109 g) over the study period. Concurrently, the net loss in salt marsh coverage led to a loss in below ground C accumulation capacity of 2.0·109 g/yr, whereas the net expansion of mangrove wetlands led to an added below ground C accumulation capacity of 0.4·109 g/yr. Biomarker data show that neutral carbohydrates and lignin contributed 30-70% and 10-40% of total C, respectively, in plant litter and surface sediments. Sharp declines of carbohydrate yields with depth occur parallel to increases in lignin

Functional Role of Native and Invasive Filter-Feeders, and the Effect of Parasites: Learning from Hypersaline Ecosystems.

Science.gov (United States)

Sánchez, Marta I; Paredes, Irene; Lebouvier, Marion; Green, Andy J

2016-01-01

Filter-feeding organisms are often keystone species with a major influence on the dynamics of aquatic ecosystems. Studies of filtering rates in such taxa are therefore vital in order to understand ecosystem functioning and the impact of natural and anthropogenic stressors such as parasites, climate warming and invasive species. Brine shrimps Artemia spp. are the dominant grazers in hypersaline systems and are a good example of such keystone taxa. Hypersaline ecosystems are relatively simplified environments compared with much more complex freshwater and marine ecosystems, making them suitable model systems to address these questions. The aim of this study was to compare feeding rates at different salinities and temperatures between clonal A. parthenogenetica (native to Eurasia and Africa) and the invasive American brine shrimp A. franciscana, which is excluding native Artemia from many localities. We considered how differences observed in laboratory experiments upscale at the ecosystem level across both spatial and temporal scales (as indicated by chlorophyll-a concentration and turbidity). In laboratory experiments, feeding rates increased at higher temperatures and salinities in both Artemia species and sexes, whilst A. franciscana consistently fed at higher rates. A field study of temporal dynamics revealed significantly higher concentrations of chlorophyll-a in sites occupied by A. parthenogenetica, supporting our experimental findings. Artemia parthenogenetica density and biomass were negatively correlated with chlorophyll-a concentration at the spatial scale. We also tested the effect of cestode parasites, which are highly prevalent in native Artemia but much rarer in the invasive species. The cestodes Flamingolepis liguloides and Anomotaenia tringae decreased feeding rates in native Artemia, whilst Confluaria podicipina had no significant effect. Total parasite prevalence was positively correlated with turbidity. Overall, parasites are likely to reduce

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...... organisational levels. Emergence caused by constraints at both the component and system levels gives rise to phenomena that can create links between the ecosystem and operational levels. To create these links, the ecosystem's functional elements must be grouped according to their functionality, ignoring any...

Microbial Communities in the Vertical Atmosphere: Effects of Urbanization and the Natural Environment in Four North American Ecosystems

Science.gov (United States)

Docherty, K. M.; Lemmer, K. M.; Domingue, K. D.; Spring, A.; Kerber, T. V.; Mooney, M. M.

2017-12-01

Airborne transport of microbial communities is a key component of the global ecosystem because it serves as a mechanism for dispersing microbial life between all surface habitats on the planet. However, most of our understanding of airborne microbial distribution is derived from samples collected near the ground. Little is understood about how the vertical layers of the air may act as a habitat filter or how local terrestrial ecosystems contribute to a vast airborne microbial seedbank. Specifically, urbanization may fundamentally alter the terrestrial sources of airborne microbial biodiversity. To address this question, we conducted airborne sampling at minimally disturbed natural sites and paired urban sites in 4 different North American ecosystems: shortgrass steppe, desert scrub, eastern deciduous forest, and northern mesic forest. All natural area sites were co-located with NEON/Ameriflux tower sites collecting atmospheric data. We developed an airborne sampling platform that uses tethered helikites at 3 replicate locations within each ecosystem to launch remote-controlled sampler payloads. We designed sampler payloads to collect airborne bacteria and fungi from 150, 30 and 2 m above the ground. Payload requirements included: ability to be disinfected and remain contaminant-free during transport, remote open/close functionality, payload weight under 6 lbs and automated collection of weather data. After sampling for 6 hours at each location, we extracted DNA collected by the samplers. We also extracted DNA from soil and plant samples collected from each location, and characterized ground vegetation. We conducted bacterial 16S amplicon-based sequencing using Mi-Seq and sequence analysis using QIIME. We used ArcGIS to determine percent land use coverage. Our results demonstrate that terrestrial ecosystem type is the most important factor contributing to differences in airborne bacterial community composition, and that communities differed by ecosystem. The

Body condition, diet and ecosystem function of red deer (Cervus elaphus in a fenced nature reserve

Directory of Open Access Journals (Sweden)

Camilla Fløjgaard

2017-07-01

Full Text Available Body condition, as a sign of animal welfare, is of management concern in rewilding projects where fenced animals are subject to winter starvation, which may conflict with animal welfare legislation. Investigating the relationship between body condition, age, sex, diet quality and diet composition is therefore relevant to increase understanding of herbivores' ecosystem function and to inform management. In this study, we focused on red deer, Cervus elaphus, in a fenced nature reserve in Denmark, where the deer are managed as ecosystem engineers to contribute to biodiversity conservation. We measured body mass and body size of 91 culled red deer, and determined diet composition using DNA metabarcoding and diet quality using fecal nitrogen on 246 fecal samples. We found that body condition was predicted by age and diet composition, but not diet quality. We also found that individuals of different body condition had different diets, i.e., the fecal samples of red deer in poorer body condition contained significantly more Ericaceae sequences than red deer in good body condition. This may imply that certain functions of red deer in ecosystems, such as regeneration of heather by grazing, may depend on variation in body condition within the population. Our findings call for the need to consider the consequences of management practices, including culling or supplemental feeding, on the outcomes of habitat restoration, and more broadly underline the importance of preserving the overall breath of herbivore ecosystem functions for effective biodiversity conservation.

Impacts of Woody Invader Dillenia suffruticosa (Griff. Martelli on Physio-chemical Properties of Soil and, Below and Above Ground Flora

Directory of Open Access Journals (Sweden)

B.A.K. Wickramathilake

2014-01-01

Full Text Available Dillenia suffruticosa (Griffith Martelli, that spreads fast in low-lying areas in wet zone of Sri Lanka is currently listed as a nationally important Invasive Alien Species that deserves attention in ecological studies. Thus, impact of this woody invader on physical, chemical properties of soil and below and above ground flora was investigated. Five sampling sites were identified along a distance of 46km from Avissawella to Ratnapura. At each site, two adjacent plots [1m x10m each for D. suffruticosa present (D+ and absent (D-] were outlined. Physical and chemical soil parameters, microbial biomass and number of bacterial colonies in soil were determined using standard procedures and compared between D+ and D- by ANOVA using SPSS. Rate of decomposition of D. suffruticosa leaves was also determined using the litter bag technique at 35% and 50% moisture levels. Above ground plant species richness in sample stands was compared using Jaccard and Sorenson diversity indices.  Decomposition of D. suffruticosa leaves was slow, but occurred at a more or less similar rate irrespective of moisture content of soil. Particle size distribution in D+ soil showed a much higher percentage of large soil particles.  Higher % porosity in D+ sites was a clear indication that the soil was aerated.  The pH was significantly lower for D+ than D- thus developing acidic soils whereas conductivity has been significantly high making soil further stressed. The significant drop in Cation Exchange Capacity (CEC in D+ soil was a remarkable finding to be concerned with as it correlated with fertility of soil. Significantly higher values of phosphates reported in D+ soil support the idea that plant invaders are capable to increase phosphates in soil. Higher biomass values recorded for D+ sites together with higher number of bacterial colonies could be related to the unexpectedly recorded higher Organic Carbon. Both  the  Jaccard  and  Sorenson   indices indicated  that

Radiological risk assessment of U(nat) in the ground water around Jaduguda uranium mining complex

International Nuclear Information System (INIS)

Sethy, N.K.; Jha, V.N.; Shukla, A.K.; Tripathi, R.M.; Puranik, V.D.

2010-01-01

Uranium is present naturally in earth crust and hence at trace level in ground water, sea water, building materials etc. Naturally occurring radionuclide originating from industrial activities, metal mining and waste depository may contribute to the nearby ground water by radionuclide migration. Ground water ecosystem surrounding the uranium processing facility at Jaduguda has been studied for natural uranium distribution. In the present study, the drinking water sources at various distance zone (with in 1.6 km, 1.6-5 km and > 5km) covering all directions around the waste depository (tailings pond) have been investigated for uranium content. Evaluation of intake, ingestion dose and subsequent risk for population residing around the tailings pond has been carried out. Annual intake of uranium through drinking water for members of public residing around the uranium complex is found to be in the range of 41.8 - 44.4 Bq.y -1 . The intake and ingestion dose is appreciably low ( -1 ) which is far below the WHO recommended level of 100 Sv.y -1 . The life time radiological risk due to uranium natural in drinking water is insignificant and found to be of the order of 10 -6 . (author)

The Building Blocks of Life Move from Ground to Tree to Animal and Back to Ground

Science.gov (United States)

Davidson, E. A.

2015-12-01

I generally use combinations of big words to describe my science, such as biogeochemistry, ecosystem ecology, nutrient cycling, stoichiometry, tropical deforestation, land-use change, agricultural intensification, eutrophication, greenhouse gas emissions, and sustainable development. I didn't expect to use any of these words, but I was surprised that I couldn't use some others that seem simple enough to me, such as farm, plant, soil, and forest. I landed on "building blocks" as my metaphor for the forms of carbon, nitrogen, phosphorus, and other elements that I study as they cycle through and among ecosystems. I study what makes trees and other kinds of life grow. We all know that they need the sun and that they take up water from the ground, but what else do trees need from the ground? What do animals that eat leaves and wood get from the trees? Just as we need building blocks to grow our bodies, trees and animals also need building blocks for growing their bodies. Trees get part of their building blocks from the ground and animals get theirs from what they eat. When animals poop and when leaves fall, some of their building blocks return to the ground. When they die, their building blocks also go back to the ground. I also study what happens to the ground, the water, and the air when we cut down trees, kill or shoo away the animals, and make fields to grow our food. Can we grow enough food and still keep the ground, water, and air clean? I think the answer is yes, but it will take better understanding of how all of those building blocks fit together and move around, from ground to tree to animal and back to ground.

Regional analysis of ground and above-ground climate

Science.gov (United States)

1981-12-01

The regional suitability of underground construction as a climate control technique is discussed with reference to (1) a bioclimatic analysis of long term weather data for 29 locations in the United States to determine appropriate above ground climate control techniques, (2) a data base of synthesized ground temperatures for the coterminous United States, and (3) monthly dew point ground temperature comparisons for identifying the relative likelihood of condensation from one region to another. It is concluded that the suitability of Earth tempering as a practice and of specific Earth sheltered design stereotypes varies geographically; while the subsurface almost always provides a thermal advantage on its own terms when compared to above ground climatic data, it can, nonetheless, compromise the effectiveness of other, regionally more important climate control techniques. Reviews of above and below ground climate mapping schemes related to human comfort and architectural design, and detailed description of a theoretical model of ground temperature, heat flow, and heat storage in the ground are included. Strategies of passive climate control are presented in a discussion of the building bioclimatic analysis procedure which has been applied in a computer analysis of 30 years of weather data for each of 20 locations in the United States.

Regional analysis of ground and above-ground climate

Energy Technology Data Exchange (ETDEWEB)

1981-12-01

The regional suitability of underground construction as a climate control technique is discussed with reference to (1) a bioclimatic analysis of long-term weather data for 29 locations in the United States to determine appropriate above ground climate control techniques, (2) a data base of synthesized ground temperatures for the coterminous United States, and (3) monthly dew point ground temperature comparisons for identifying the relative likelihood of condensation from one region to another. It is concluded that the suitability of earth tempering as a practice and of specific earth-sheltered design stereotypes varies geographically; while the subsurface almost always provides a thermal advantage on its own terms when compared to above ground climatic data, it can, nonetheless, compromise the effectiveness of other, regionally more important climate control techniques. Also contained in the report are reviews of above and below ground climate mapping schemes related to human comfort and architectural design, and detailed description of a theoretical model of ground temperature, heat flow, and heat storage in the ground. Strategies of passive climate control are presented in a discussion of the building bioclimatic analysis procedure which has been applied in a computer analysis of 30 years of weather data for each of 29 locations in the United States.

Ecosystem Services : In Nordic Freshwater Management

DEFF Research Database (Denmark)

Magnussen, Kristin; Hasler, Berit; Zandersen, Marianne

Human wellbeing is dependent upon and benefit from ecosystem services which are delivered by well-functioning ecosystems. Ecosystem services can be mapped and assessed consistently within an ecosystem service framework. This project aims to explore the use and usefulness of the ecosystem service ...

Remote sensing of Essential Biodiversity Variables: new measurements linking ecosystem structure, function and composition

Science.gov (United States)

Schimel, D.; Pavlick, R.; Stavros, E. N.; Townsend, P. A.; Ustin, S.; Thompson, D. R.

2017-12-01

Remote sensing can inform a wide variety of essential biodiversity variables, including measurements that define primary productivity, forest structure, biome distribution, plant communities, land use-land cover change and climate drivers of change. Emerging remote sensing technologies can add significantly to remote sensing of EBVs, providing new, large scale insights on plant and habitat diversity itself, as well as causes and consequences of biodiversity change. All current biodiversity assessments identify major data gaps, with insufficient coverage in critical regions, limited observations to monitor change over time, with very limited revisit of sample locations, as well as taxon-specific biased biases. Remote sensing cannot fill many of the gaps in global biodiversity observations, but spectroscopic measurements in terrestrial and marine environments can aid in assessing plant/phytoplankton functional diversity and efficiently reveal patterns in space, as well as changes over time, and, by making use of chlorophyll fluorescence, reveal associated patterns in photosynthesis. LIDAR and RADAR measurements quantify ecosystem structure, and can precisely define changes due to growth, disturbance and land use. Current satellite-based EBVs have taken advantage of the extraordinary time series from LANDSAT and MODIS, but new measurements more directly reveal ecosystem structure, function and composition. We will present results from pre-space airborne studies showing the synergistic ability of a suite of new remote observation techniques to quantify biodiversity and ecosystem function and show how it changes during major disturbance events.

Peatland Bryophytes in a Changing Environment : Ecophysiological Traits and Ecosystem Function

OpenAIRE

Granath, Gustaf

2012-01-01

Peatlands are peat forming ecosystems in which not fully decomposed plant material builds up the soil. The sequestration of carbon into peat is mainly associated with the bryophyte genus Sphagnum (peat mosses), which dominate and literally form most peatlands. The responses of Sphagnum to environmental change help us to understand peatland development and function and to predict future changes in a rapidly changing world. In this thesis, the overarching aim was to use ecophysiological traits ...

Protected area certificates: gaining ground for better ecosystem protection?

Science.gov (United States)

Segerstedt, Anna; Grote, Ulrike

2015-06-01

Protected areas are vital to sustain a number of ecosystem services. Yet, many protected areas are underfinanced and lack management effectiveness. Protected area certificates have been suggested as a way to resolve these problems. This instrument would allow land managers to certify an area if it meets certain conservation criteria. The certificates could then be sold on an international market, for example to companies and any consumers that are interested in environmental protection. Some pilot initiatives have been launched, yet little is known about future demand and features of protected area certificates. To fill this knowledge gap, we conduct a choice experiment with close to 400 long-distance tourists from Germany as a potential group of buyers. Our results indicate that the respondents have the highest willingness to pay for certificates that conserve sensitive ecosystems and in addition to this lead to poverty reduction and safeguard water resources. For other attributes such as a greenhouse gas reduction, the preferences are less significant. Overall, the results are rather homogenous irrespective of where the protected areas are located. These insights are important for the future design and marketing of protected area certificates.

Model evaluation of seepage from uranium tailings disposal above and below the water table

International Nuclear Information System (INIS)

Nelson, R.W.; Meyer, P.R.; Oberlander, P.L.; Sneider, S.C.; Mayer, D.W.; Reisenauer, A.E.

1983-03-01

Model simulations identify the rate and amount of leachate released to the environment if disposed uranium mill tailings come into contact with ground water or if seepage from tailings reaches ground water. In this study, simulations of disposal above and below the water table, with various methods of leachate control, were compared. Three leachate control methods were used in the comparisons: clay bottom liners; stub-sidewall clay liners; and tailings drains with sumps, with the effluent pumped back from the sumps. The best leachate control for both above and below the water table is a combination of the three methods. The combined methods intercept up to 80% of the leachate volume in pits above the water table and intercept essentially all of the leachate in pits below the water table. Effluent pumping, however, requires continuous energy costs and an alternative method of disposal for the leachate that cannot be reused as makeup water in the mill process. Without the drains or effluent pumping, the clay bottom liners have little advantage in terms of the total volume of leachate lost. The clay liners do reduce the rate of leachate flow to the ground water, but the flow continues for a longer time. The buffering, sorption, and chemical reactions of the leachate passing directly through the liner are also advantages of the liner

Predicting ecosystem vulnerability to biodiversity loss from community composition.

Science.gov (United States)

Heilpern, Sebastian A; Weeks, Brian C; Naeem, Shahid

2018-05-01

Ecosystems vary widely in their responses to biodiversity change, with some losing function dramatically while others are highly resilient. However, generalizations about how species- and community-level properties determine these divergent ecosystem responses have been elusive because potential sources of variation (e.g., trophic structure, compensation, functional trait diversity) are rarely evaluated in conjunction. Ecosystem vulnerability, or the likely change in ecosystem function following biodiversity change, is influenced by two types of species traits: response traits that determine species' individual sensitivities to environmental change, and effect traits that determine a species' contribution to ecosystem function. Here we extend the response-effect trait framework to quantify ecosystem vulnerability and show how trophic structure, within-trait variance, and among-trait covariance affect ecosystem vulnerability by linking extinction order and functional compensation. Using in silico trait-based simulations we found that ecosystem vulnerability increased when response and effect traits positively covaried, but this increase was attenuated by decreasing trait variance. Contrary to expectations, in these communities, both functional diversity and trophic structure increased ecosystem vulnerability. In contrast, ecosystem functions were resilient when response and effect traits covaried negatively, and variance had a positive effect on resiliency. Our results suggest that although biodiversity loss is often associated with decreases in ecosystem functions, such effects are conditional on trophic structure, and the variation within and covariation among response and effect traits. Taken together, these three factors can predict when ecosystems are poised to lose or gain function with ongoing biodiversity change. © 2018 by the Ecological Society of America.

Incorporating ecosystem function concept in environmental planning and decision making by means of multi-criteria evaluation: the case-study of Kalloni, Lesbos, Greece.

Science.gov (United States)

Oikonomou, Vera; Dimitrakopoulos, Panayiotis G; Troumbis, Andreas Y

2011-01-01

Nature provides life-support services which do not merely constitute the basis for ecosystem integrity but also benefit human societies. The importance of such multiple outputs is often ignored or underestimated in environmental planning and decision making. The economic valuation of ecosystem functions or services has been widely used to make these benefits economically visible and thus address this deficiency. Alternatively, the relative importance of the components of ecosystem value can be identified and compared by means of multi-criteria evaluation. Hereupon, this article proposes a conceptual framework that couples ecosystem function analysis, multi criteria evaluation and social research methodologies for introducing an ecosystem function-based planning and management approach. The framework consists of five steps providing the structure of a participative decision making process which is then tested and ratified, by applying the discrete multi-criteria method NAIADE, in the Kalloni Natura 2000 site, on Lesbos, Greece. Three scenarios were developed and evaluated with regard to their impacts on the different types of ecosystem functions and the social actors' value judgements. A conflict analysis permitted the better elaboration of the different views, outlining the coalitions formed in the local community and shaping the way towards reaching a consensus.

Quantifying confidence in density functional theory predictions of magnetic ground states

Science.gov (United States)

Houchins, Gregory; Viswanathan, Venkatasubramanian

2017-10-01

Density functional theory (DFT) simulations, at the generalized gradient approximation (GGA) level, are being routinely used for material discovery based on high-throughput descriptor-based searches. The success of descriptor-based material design relies on eliminating bad candidates and keeping good candidates for further investigation. While DFT has been widely successfully for the former, oftentimes good candidates are lost due to the uncertainty associated with the DFT-predicted material properties. Uncertainty associated with DFT predictions has gained prominence and has led to the development of exchange correlation functionals that have built-in error estimation capability. In this work, we demonstrate the use of built-in error estimation capabilities within the BEEF-vdW exchange correlation functional for quantifying the uncertainty associated with the magnetic ground state of solids. We demonstrate this approach by calculating the uncertainty estimate for the energy difference between the different magnetic states of solids and compare them against a range of GGA exchange correlation functionals as is done in many first-principles calculations of materials. We show that this estimate reasonably bounds the range of values obtained with the different GGA functionals. The estimate is determined as a postprocessing step and thus provides a computationally robust and systematic approach to estimating uncertainty associated with predictions of magnetic ground states. We define a confidence value (c-value) that incorporates all calculated magnetic states in order to quantify the concurrence of the prediction at the GGA level and argue that predictions of magnetic ground states from GGA level DFT is incomplete without an accompanying c-value. We demonstrate the utility of this method using a case study of Li-ion and Na-ion cathode materials and the c-value metric correctly identifies that GGA-level DFT will have low predictability for NaFePO4F . Further, there

Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

Science.gov (United States)

Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

2013-01-01

Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

Science.gov (United States)

Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

2013-01-01

Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

Directory of Open Access Journals (Sweden)

Rachel L Vannette

2013-09-01

Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

Declining plant nitrogen supply and carbon accumulation in ageing primary boreal forest ecosystems

Science.gov (United States)

Högberg, Mona N.; Yarwood, Stephanie A.; Trumbore, Susan; Högberg, Peter

2016-04-01

Boreal forest soils are commonly characterized by a low plant nitrogen (N) supply. A high tree below-ground allocation of carbon (C) to roots and soil microorganisms in response to the shortage of N may lead to high microbial immobilisation of N, thus aggravating the N limitation. We studied the N supply at a Swedish boreal forest ecosystem chronosequence created by new land rising out of the sea due to iso-static rebound. The youngest soils develop with meadows by the coast, followed by a zone of dinitrogen fixing alder trees, and primary boreal conifer forest on ground up to 560 years old. With increasing ecosystem age, the proportion of microbial C out of the total soil C pool from the youngest to the oldest coniferous ecosystem was constant (c. 1-1.5%), whereas immobilised N (microbial N out of total soil N) increased and approached the levels commonly observed in similar boreal coniferous forests (c. 6-7 %), whereas gross N mineralization declined. Simultaneously, plant foliar N % decreased and the natural abundance of N-15 in the soil increased. More specifically, the difference in N-15 between plant foliage and soil increased, which is related to greater retention of N-15 relative to N-14 by ectomycorrhizal fungi as N is taken up from the soil and some N is transferred to the plant host. In the conifer forest, where these changes were greatest, we found increased fungal biomass in the F- and H-horizons of the mor-layer, in which ectomycorrhizal fungi are known to dominate (the uppermost horizon with litter and moss is dominated by saprotrophic fungi). Hence, we propose that the decreasing N supply to the plants and the subsequent decline in plant production in ageing boreal forests is linked to high tree belowground C allocation to C limited ectomycorrhizal fungi (and other soil microorganisms), a strong sink for available soil N. Data on organic matter C-14 suggested that the largest input of recently fixed plant C occurred in the younger coniferous forest

Influence of benthic macrofauna community shifts on ecosystem functioning in shallow estuaries

Directory of Open Access Journals (Sweden)

Erik eKristensen

2014-09-01

Full Text Available We identify how ecosystem functioning in shallow estuaries is affected by shifts in benthic fauna communities. We use the shallow estuary, Odense Fjord, Denmark, as a case study to test our hypotheses that (1 shifts in benthic fauna composition and species functional traits affect biogeochemical cycling with cascading effects on ecological functioning, which may (2 modulate pelagic primary productivity with feedbacks to the benthic system. Odense Fjord is suitable because it experienced dramatic shifts in benthic fauna community structure from 1998 to 2008. We focused on infaunal species with emphasis on three dominating burrow-dwelling polychaetes: the native Nereis (Hediste diversicolor and Arenicola marina, and the invasive Marenzelleria viridis. The impact of functional traits in the form of particle reworking and ventilation on biogeochemical cycles, i.e. sediment metabolism and nutrient dynamics, was determined from literature data. Historical records of summer nutrient levels in the water column of the inner Odense Fjord show elevated concentrations of NH4+ and NO3- (DIN during the years 2004-2006, exactly when the N. diversicolor population declined and A. marina and M. viridis populations expanded dramatically. In support of our first hypothesis, we show that excess NH4+ delivery from the benthic system during the A. marina and M. viridis expansion period enriched the overlying water in DIN and stimulated phytoplankton concentration. The altered benthic-pelagic coupling and stimulated pelagic production may, in support of our second hypothesis, have feedback to the benthic system by changing the deposition of organic material. We therefore advice to identify the exact functional traits of the species involved in a community shift before studying its impact on ecosystem functioning. We also suggest studying benthic community shifts in shallow environments to obtain knowledge about the drivers and controls before exploring deep

The resilience and functional role of moss in boreal and arctic ecosystems

Energy Technology Data Exchange (ETDEWEB)

Turetsky, Merritt; Bond-Lamberty, Benjamin; Euskirchen, Eugenie S.; Talbot, Julie; Frolking, Steve; McGuire, A. David; Tuittila, Eeva-Stiina

2012-08-24

Mosses in boreal and arctic ecosystems are ubiquitous components of plant communities, represent an important component of plant diversity, and strongly influence the cycling of water, nutrients, energy and carbon. Here we use a literature review and synthesis as well as model simulations to explore the role of moss in ecological stability and resilience. Our literature review of moss community responses to disturbance showed all possible responses (increases, decreases, no change) within most disturbance categories in boreal and arctic regions. Our modeling simulations suggest that loss of moss within northern plant communities will reduce soil carbon accumulation primarily by influencing decomposition rates and soil nitrogen availability. While two models (HPM and STM-TEM) showed a significant effect of moss removal, results from the Biome-BGC and DVM-TEM models suggest that northern, moss-rich ecosystems would need to experience extreme perturbation before mosses were eliminated. We highlight a number of issues that have not been adequately explored in moss communities, such as functional redundancy and singularity, relationships between response and effect traits, phenotypical plasticity in traits, and whether the effects of moss on ecosystem processes scale with local abundance. We also suggest that as more models explore issues related to ecological resilience, issues related to both parameter and conceptual uncertainty should be addressed: are the models more limited by uncertainty in the parameterization of the processes included or by what is not represented in the model at all? It seems clear from our review that mosses need to be incorporated into models as one or more plant functional types, but more empirical work is needed to determine how to best aggregate species.

Predicting ecosystem functioning from plant traits: Results from a multi-scale ecophsiological modeling approach

NARCIS (Netherlands)

Wijk, van M.T.

2007-01-01

Ecosystem functioning is the result of processes working at a hierarchy of scales. The representation of these processes in a model that is mathematically tractable and ecologically meaningful is a big challenge. In this paper I describe an individual based model (PLACO¿PLAnt COmpetition) that

Changes in food web structure and ecosystem functioning of a large, shallow Chinese lake during the 1950s, 1980s and 2000s

DEFF Research Database (Denmark)

Kong, Xiangzhen; He, Wei; Liu, Wenxiu

2016-01-01

that hydrological regulation may play a significant role in driving all of these changes in Lake Chaohu in addition to eutrophication and intensive fishery. Overall, we strongly advocate the identification of a threshold in abundance of zooplanktivorous fish, an integrated strategy for future ecological restoration......Food web structure dynamics and ecosystem functioning are strongly linked, and both are indispensable in evaluating ecosystem development in lakes under multiple anthropogenic stressors. However, model-based approaches concerning the changes in food web structure and ecosystem functioning...... validated by the stable isotope-determined trophic level (TL) for each functional group, which indicated an acceptable model performance. Over time, we observed a collapse of the food web toward a simplified structure and decreasing biodiversity and trophic interactions. The lake ecosystem was approaching...

A morphometric analysis of vegetation patterns in dryland ecosystems

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Mander, Luke; Dekker, Stefan C.; Li, Mao; Mio, Washington; Punyasena, Surangi W.; Lenton, Timothy M.

2017-02-01

Vegetation in dryland ecosystems often forms remarkable spatial patterns. These range from regular bands of vegetation alternating with bare ground, to vegetated spots and labyrinths, to regular gaps of bare ground within an otherwise continuous expanse of vegetation. It has been suggested that spotted vegetation patterns could indicate that collapse into a bare ground state is imminent, and the morphology of spatial vegetation patterns, therefore, represents a potentially valuable source of information on the proximity of regime shifts in dryland ecosystems. In this paper, we have developed quantitative methods to characterize the morphology of spatial patterns in dryland vegetation. Our approach is based on algorithmic techniques that have been used to classify pollen grains on the basis of textural patterning, and involves constructing feature vectors to quantify the shapes formed by vegetation patterns. We have analysed images of patterned vegetation produced by a computational model and a small set of satellite images from South Kordofan (South Sudan), which illustrates that our methods are applicable to both simulated and real-world data. Our approach provides a means of quantifying patterns that are frequently described using qualitative terminology, and could be used to classify vegetation patterns in large-scale satellite surveys of dryland ecosystems.

Relationships between Plant Diversity and the Abundance and α-Diversity of Predatory Ground Beetles (Coleoptera: Carabidae) in a Mature Asian Temperate Forest Ecosystem

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Zou, Yi; Sang, Weiguo; Bai, Fan; Axmacher, Jan Christoph

2013-01-01

A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems. PMID:24376582

Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae) in a mature Asian temperate forest ecosystem.

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Zou, Yi; Sang, Weiguo; Bai, Fan; Axmacher, Jan Christoph

2013-01-01

A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.

Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae in a mature Asian temperate forest ecosystem.

Directory of Open Access Journals (Sweden)

Yi Zou

Full Text Available A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.

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

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Green, Robert O.; Rogez, Francois; Green, Rob; Ungar, Steve; Knox, Robert; Asner, Greg; Muller-Karger, Frank; Bissett, Paul; Chekalyuk, Alex; Dierssen, Heidi;

Desertification, salinization, and biotic homogenization in a dryland river ecosystem

Science.gov (United States)

Miyazono, S.; Patino, Reynaldo; Taylor, C.M.

2015-01-01

This study determined long-term changes in fish assemblages, river discharge, salinity, and local precipitation, and examined hydrological drivers of biotic homogenization in a dryland river ecosystem, the Trans-Pecos region of the Rio Grande/Rio Bravo del Norte (USA/Mexico). Historical (1977-1989) and current (2010-2011) fish assemblages were analyzed by rarefaction analysis (species richness), nonmetric multidimensional scaling (composition/variability), multiresponse permutation procedures (composition), and paired t-test (variability). Trends in hydrological conditions (1970s-2010s) were examined by Kendall tau and quantile regression, and associations between streamfiow and specific conductance (salinity) by generalized linear models. Since the 1970s, species richness and variability of fish assemblages decreased in the Rio Grande below the confluence with the Rio Conchos (Mexico), a major tributary, but not above it. There was increased representation of lower-flow/higher-salinity tolerant species, thus making fish communities below the confluence taxonomically and functionally more homogeneous to those above it. Unlike findings elsewhere, this biotic homogenization was due primarily to changes in the relative abundances of native species. While Rio Conchos discharge was > 2-fold higher than Rio Grande discharge above their confluence, Rio Conchos discharge decreased during the study period causing Rio Grande discharge below the confluence to also decrease. Rio Conchos salinity is lower than Rio Grande salinity above their confluence and, as Rio Conchos discharge decreased, it caused Rio Grande salinity below the confluence to increase (reduced dilution). Trends in discharge did not correspond to trends in precipitation except at extreme-high (90th quantile) levels. In conclusion, decreasing discharge from the Rio Conchos has led to decreasing flow and increasing salinity in the Rio Grande below the confluence. This spatially uneven desertification and

Detecting ecosystem performance anomalies for land management in the upper colorado river basin using satellite observations, climate data, and ecosystem models

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Gu, Yingxin; Wylie, B.K.

2010-01-01

This study identifies areas with ecosystem performance anomalies (EPA) within the Upper Colorado River Basin (UCRB) during 2005-2007 using satellite observations, climate data, and ecosystem models. The final EPA maps with 250-m spatial resolution were categorized as normal performance, underperformance, and overperformance (observed performance relative to weather-based predictions) at the 90% level of confidence. The EPA maps were validated using "percentage of bare soil" ground observations. The validation results at locations with comparable site potential showed that regions identified as persistently underperforming (overperforming) tended to have a higher (lower) percentage of bare soil, suggesting that our preliminary EPA maps are reliable and agree with ground-based observations. The 3-year (2005-2007) persistent EPA map from this study provides the first quantitative evaluation of ecosystem performance anomalies within the UCRB and will help the Bureau of Land Management (BLM) identify potentially degraded lands. Results from this study can be used as a prototype by BLM and other land managers for making optimal land management decisions. ?? 2010 by the authors.

Bee community as a source of energy in the production of food, honey-plants in the ecosystem of Croatian Forests' hunting grounds.

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Tucak, Zvonimir; Beuk, Darko; Jumić, Vlado; Tusek, Tatjana; Vladimir-Knezević, Sanda; Tolusić, Zdravko; Skrivanko, Mario; Konjarović, Anastazija; Aladić, Krunoslav; Cupurdija, Edita

2009-12-01

In addition to the process of photosynthesis, the bee community is the main source of energy in food production, honey-plants used by game and people in the hunting grounds ecosystem. It is a well-known fact that thousands of plant species depend on the presence of bee communities (pollination, fertilization). In this paper we studied the presence of the bee community in the hunting grounds of Croatian Forests, and their influence on the number of game (wild pigs), as well as the quality of honey, honey plants in the hunting grounds used by people and game. We established the total number of game (wild boars). The honey quality parameters were determined using the Harmonised methods of the European Honey (Bogdanov et al., 1997) and the pollen analysis by were conducted according to Harmonised methods of melissopalynology (Von der Ohe et al., 2004). Research results indicate that the presence of the bee community influences the number of wild boars from 3-18%, and the quality of honey is in line with the European and world standards. The SAS/STAT package was used for the statistical analysis (SAS Institute Inc., 2000). The significance of the differences among the groups was determined by Duncan test.

Diversity-interaction modeling: estimating contributions of species identities and interactions to ecosystem function

DEFF Research Database (Denmark)

Kirwan, L; Connolly, J; Finn, J A

2009-01-01

to the roles of evenness, functional groups, and functional redundancy. These more parsimonious descriptions can be especially useful in identifying general diversity-function relationships in communities with large numbers of species. We provide an example of the application of the modeling framework......We develop a modeling framework that estimates the effects of species identity and diversity on ecosystem function and permits prediction of the diversity-function relationship across different types of community composition. Rather than just measure an overall effect of diversity, we separately....... These models describe community-level performance and thus do not require separate measurement of the performance of individual species. This flexible modeling approach can be tailored to test many hypotheses in biodiversity research and can suggest the interaction mechanisms that may be acting....

Ground Water and Climate Change

Science.gov (United States)

Taylor, Richard G.; Scanlon, Bridget; Doell, Petra; Rodell, Matt; van Beek, Rens; Wada, Yoshihide; Longuevergne, Laurent; Leblanc, Marc; Famiglietti, James S.; Edmunds, Mike;

Restoring ecosystem functions and services by overcoming soil threats - The case of Mt. Hekla area in Iceland

Science.gov (United States)

Thorsson, Johann; Petursdottir, Thorunn

2015-04-01

Soils are one of the main fundamental bodies of terrestrial ecosystems. Soil functions contribute substantially to the ecosystem services humans and all other living beings depend on. Current soil threats are in most cases related to anthropogenic impacts and derived environmental pressures. For instance, overexploitation has in many cases damaged ecosystem resilience, affected current equilibrium and caused severe soil degradation. The resulting dysfunctional ecosystems are incapable of providing necessary ecosystem services. In such cases ecosystem restoration is necessary to restore ecosystem functions and ecological succession. The Mt. Hekla area in Iceland is an example of land suffering from accelerated erosion amplified by anthropogenic impacts. The area is 900 km2 located in South Iceland in the vicinity of the volcano Mt. Hekla. Today over 40% of the area is classified as eroded but historical documents indicate that vast part of the area were fertile and vegetated at the time of settlement, 1100 years ago; hence was able to withstand the geological disturbances occurring prior to the arrival of man as is obvious from the pristine woody patches still remaining. Severe soil degradation followed the large-scale deforestation and overgrazing that took place within the area. The initial land degradation event is considered to have occurred in the 11th century, but has been ongoing since then in several episodes. The Þjórsá glacial river flows through the area and carries enormous amounts of sediments every year. After the deforestation, the ecosystem resilience was damaged and the land left exposed to the elements. Eventually large scale wind erosion started, followed with water erosion and increased impact of freeze-thaw processes. The Soil Conservation Service of Iceland started working in the area in the early 20th century and land reclamation operations have been ongoing until this day. Considerable successes have been made as is manifested in the fact

Bryophytes and Organic layers Control Uptake of Airborne Nitrogen in Low-N Environments

Science.gov (United States)

Bähring, Alexandra; Fichtner, Andreas; Friedrich, Uta; von Oheimb, Goddert; Härdtle, Werner

2017-01-01

The effects of atmospheric nitrogen (N) deposition on ecosystem functioning largely depend on the retention of N in different ecosystem compartments, but accumulation and partitioning processes have rarely been quantified in long-term field experiments. In the present study we analysed for the first time decadal-scale flows and allocation patterns of N in a heathland ecosystem that has been subject to airborne N inputs over decades. Using a long-term 15N tracer experiment, we quantified N retention and flows to and between ecosystem compartments (above-ground/below-ground vascular biomass, moss layer, soil horizons, leachate). After 9 years, about 60% of the added 15N-tracer remained in the N cycle of the ecosystem. The moss layer proved to be a crucial link between incoming N and its allocation to different ecosystem compartments (in terms of a short-term capture, but long-term release function). However, about 50% of the 15N captured and released by the moss layer was not compensated for by a corresponding increase in recovery rates in any other compartment, probably due to denitrification losses from the moss layer in the case of water saturation after rain events. The O-horizon proved to be the most important long-term sink for added 15N, as reflected by an increase in recovery rates from 18 to 40% within 8 years. Less than 2.1% of 15N were recovered in the podzol-B-horizon, suggesting that only negligible amounts of N were withdrawn from the N cycle of the ecosystem. Moreover, 15N recovery was low in the dwarf shrub above-ground biomass (account for cumulative effects of N additions into ecosystems. PMID:29375589

Consumer-driven nutrient dynamics in freshwater ecosystems: from individuals to ecosystems.

Science.gov (United States)

Atkinson, Carla L; Capps, Krista A; Rugenski, Amanda T; Vanni, Michael J

2017-11-01

The role of animals in modulating nutrient cycling [hereafter, consumer-driven nutrient dynamics (CND)] has been accepted as an important influence on both community structure and ecosystem function in aquatic systems. Yet there is great variability in the influence of CND across species and ecosystems, and the causes of this variation are not well understood. Here, we review and synthesize the mechanisms behind CND in fresh waters. We reviewed 131 articles on CND published between 1973 and 1 June 2015. The rate of new publications in CND has increased from 1.4 papers per year during 1973-2002 to 7.3 per year during 2003-2015. The majority of investigations are in North America with many concentrating on fish. More recent studies have focused on animal-mediated nutrient excretion rates relative to nutrient demand and indirect impacts (e.g. decomposition). We identified several mechanisms that influence CND across levels of biological organization. Factors affecting the stoichiometric plasticity of consumers, including body size, feeding history and ontogeny, play an important role in determining the impact of individual consumers on nutrient dynamics and underlie the stoichiometry of CND across time and space. The abiotic characteristics of an ecosystem affect the net impact of consumers on ecosystem processes by influencing consumer metabolic processes (e.g. consumption and excretion/egestion rates), non-CND supply of nutrients and ecosystem nutrient demand. Furthermore, the transformation and transport of elements by populations and communities of consumers also influences the flow of energy and nutrients across ecosystem boundaries. This review highlights that shifts in community composition or biomass of consumers and eco-evolutionary underpinnings can have strong effects on the functional role of consumers in ecosystem processes, yet these are relatively unexplored aspects of CND. Future research should evaluate the value of using species traits and abiotic

An Indicator for ecosystem externalities in fishing

DEFF Research Database (Denmark)

Ravn-Jonsen, Lars; Andersen, Ken Haste; Vestergaard, Niels

Ecosystem externalities arise when one use of an ecosystem affects its other uses through the production functions of the ecosystem.We use simulations from a size-spectrum ecosystem model to investigate the ecosystem externality created by fishing of multiple species. The model is based upon...

The biodiversity-dependent ecosystem service debt.

Science.gov (United States)

Isbell, Forest; Tilman, David; Polasky, Stephen; Loreau, Michel

2015-02-01

Habitat destruction is driving biodiversity loss in remaining ecosystems, and ecosystem functioning and services often directly depend on biodiversity. Thus, biodiversity loss is likely creating an ecosystem service debt: a gradual loss of biodiversity-dependent benefits that people obtain from remaining fragments of natural ecosystems. Here, we develop an approach for quantifying ecosystem service debts, and illustrate its use to estimate how one anthropogenic driver, habitat destruction, could indirectly diminish one ecosystem service, carbon storage, by creating an extinction debt. We estimate that c. 2-21 Pg C could be gradually emitted globally in remaining ecosystem fragments because of plant species loss caused by nearby habitat destruction. The wide range for this estimate reflects substantial uncertainties in how many plant species will be lost, how much species loss will impact ecosystem functioning and whether plant species loss will decrease soil carbon. Our exploratory analysis suggests that biodiversity-dependent ecosystem service debts can be globally substantial, even when locally small, if they occur diffusely across vast areas of remaining ecosystems. There is substantial value in conserving not only the quantity (area), but also the quality (biodiversity) of natural ecosystems for the sustainable provision of ecosystem services. © 2014 John Wiley & Sons Ltd/CNRS.

The estimation ecological risk for ground ecosystems in case of nuclear power plant failures

International Nuclear Information System (INIS)

Kremlenkov, D.Yu.; Kremlenkov, M.Yu.

2004-01-01

The results of probabilistic estimation of the damage for forest and agricultural ecosystems connected with cesium-137 and strontium-90 release during hypothetical accidents at NPPs are analyzed. The concept of radioecological risk including application of the models for radioactivity transport in atmosphere and calculation of of absorbed doses in ecosystem critical groups is used for the analysis. It is proved that the probable ecological damage expressed in terms of ecosystem destruction area depends on the scale of accidental radioisotope releases, meteorological conditions and radiation resistance of critical groups in plant associations. The conclusion is made that ecological risks expressed in the form of probable area of ecosystem destruction in the zone where dose loads lay in the range from minimal ecologically significant limit up to ecologically significant limit amount to 4-9% for conifers contaminated with cesium-137 and to 2-4% for agricultural crops contaminated with strontium-90 [ru

Determination of many-electron basis functions for a quantum Hall ground state using Schur polynomials

Science.gov (United States)

Mandal, Sudhansu S.; Mukherjee, Sutirtha; Ray, Koushik

2018-03-01

A method for determining the ground state of a planar interacting many-electron system in a magnetic field perpendicular to the plane is described. The ground state wave-function is expressed as a linear combination of a set of basis functions. Given only the flux and the number of electrons describing an incompressible state, we use the combinatorics of partitioning the flux among the electrons to derive the basis wave-functions as linear combinations of Schur polynomials. The procedure ensures that the basis wave-functions form representations of the angular momentum algebra. We exemplify the method by deriving the basis functions for the 5/2 quantum Hall state with a few particles. We find that one of the basis functions is precisely the Moore-Read Pfaffian wave function.

Does species richness affect fine root biomass and production in young forest plantations?

Science.gov (United States)

Domisch, Timo; Finér, Leena; Dawud, Seid Muhie; Vesterdal, Lars; Raulund-Rasmussen, Karsten

2015-02-01

Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this could be that these stands were still young, and canopy closure had not always taken place, i.e. a situation where above- or below-ground competition did not yet exist. Another reason could be that the rooting traits of the tree species did not differ sufficiently to support niche differentiation. Our results suggested that functional group identity (i.e. conifers vs. broadleaved species) can be more important for below-ground biomass and production than the species richness itself, as conifers seemed to be more competitive in colonising the soil volume, compared to broadleaved species.

Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

Science.gov (United States)

Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

2017-12-01

Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Classical many-particle systems with unique disordered ground states

Science.gov (United States)

Zhang, G.; Stillinger, F. H.; Torquato, S.

2017-10-01

Classical ground states (global energy-minimizing configurations) of many-particle systems are typically unique crystalline structures, implying zero enumeration entropy of distinct patterns (aside from trivial symmetry operations). By contrast, the few previously known disordered classical ground states of many-particle systems are all high-entropy (highly degenerate) states. Here we show computationally that our recently proposed "perfect-glass" many-particle model [Sci. Rep. 6, 36963 (2016), 10.1038/srep36963] possesses disordered classical ground states with a zero entropy: a highly counterintuitive situation . For all of the system sizes, parameters, and space dimensions that we have numerically investigated, the disordered ground states are unique such that they can always be superposed onto each other or their mirror image. At low energies, the density of states obtained from simulations matches those calculated from the harmonic approximation near a single ground state, further confirming ground-state uniqueness. Our discovery provides singular examples in which entropy and disorder are at odds with one another. The zero-entropy ground states provide a unique perspective on the celebrated Kauzmann-entropy crisis in which the extrapolated entropy of a supercooled liquid drops below that of the crystal. We expect that our disordered unique patterns to be of value in fields beyond glass physics, including applications in cryptography as pseudorandom functions with tunable computational complexity.

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