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Sample records for grassland biome electronic

  1. Description of the Grassland Biome Project

    CSIR Research Space (South Africa)

    Mentis, MT

    1982-10-01

    Full Text Available The objectives, organization and research programme of the Grassland Biome Project are described against a background of the biome's ecological characteristics and environmental problems. Four principal research topics wil 1 be focused upon: (i...

  2. Terrestrial ecology. Comprehensive study of the grassland biome

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Terrestrial ecology and grassland biome studies are designed to characterize the biota of the Hanford Reservation, elucidate seasonal dynamics of plant productivity, decomposition and mineral behavior patterns of important plant communities, and, to study the response of these communities to important natural environmental stresses, such as weather, wildfire and man-induced alterations of communities (influenced by grazing cattle and severe mechanical disturbance of the soil, such as affected by plowing or burial of waste materials or construction activities). A detailed account of the important findings of a 5-yr study is currently being prepared by the terrestrial ecology section staff for publication as a contribution to the International Biological Program Grassland Biome project

  3. FIFE data analysis: Testing BIOME-BGC predictions for grasslands

    Science.gov (United States)

    Hunt, E. Raymond, Jr.

    1994-01-01

    The First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) was conducted in a 15 km by 15 km research area located 8 km south of Manhattan, Kansas. The site consists primarily of native tallgrass prairie mixed with gallery oak forests and croplands. The objectives of FIFE are to better understand the role of biology in controlling the interactions between the land and the atmosphere, and to determine the value of remotely sensed data for estimating climatological parameters. The goals of FIFE are twofold: the upscale integration of models, and algorithm development for satellite remote sensing. The specific objectives of the field campaigns carried out in 1987 and 1989 were the simultaneous acquisition of satellite, atmospheric, and surface data; and the understanding of the processes controlling surface energy and mass exchange. Collected data were used to study the dynamics of various ecosystem processes (photosynthesis, evaporation and transpiration, autotrophic and heterotrophic respiration, etc.). Modelling terrestrial ecosystems at scales larger than that of a homogeneous plot led to the development of simple, generalized models of biogeochemical cycles that can be accurately applied to different biomes through the use of remotely sensed data. A model was developed called BIOME-BGC (for BioGeochemical Cycles) from a coniferous forest ecosystem model, FOREST-BGC, where a biome is considered a combination of a life forms in a specified climate. A predominately C4-photosynthetic grassland is probably the most different from a coniferous forest possible, hence the FIFE site was an excellent study area for testing BIOME-BGC. The transition from an essentially one-dimensional calculation to three-dimensional, landscape scale simulations requires the introduction of such factors as meteorology, climatology, and geomorphology. By using remotely sensed geographic information data for important model inputs, process

  4. NDVI and meteorological data as indicators of the Pampa biome natural grasslands growth

    Directory of Open Access Journals (Sweden)

    Denise Cybis Fontana

    2018-04-01

    Full Text Available ABSTRACT The present study aimed to characterize the dynamics of NDVI and meteorological conditions, relating both to the annual dynamics of biomass accumulation in natural pastures of the Pampa biome as a way of subsidizing growth modeling. Forage accumulation rate data from a long-term experiment, NDVI data from the MODIS images, and meteorological data measured at the surface were used. We verify that the agrometeorological element associated to the accumulation of forage in the natural grasslands is different according to the season, which is typical of the subtropical climate. Winter is the critical season for livestock production due to the lower forage accumulation rate and lower values of NDVI, conditioned by the decrease of solar radiation and air temperature. In the summer, the limiting factor to forage accumulation is the hydric condition. It was also verified that the variability in the growth of grasslands can be associated with the ENSO phenomenon, being the El Niño favorable and the La Niña unfavorable, especially in the spring-summer period. Considering the verified associations, spectral indices combined with agrometeorological elements are recommended to the adjustment of models of forage accumulation in the Pampa biome natural grasslands.

  5. The Use of Fire Radiative Power to Estimate the Biomass Consumption Coefficient for Temperate Grasslands in the Atlantic Forest Biome

    Directory of Open Access Journals (Sweden)

    Bibiana Salvador Cabral da Costa

    Full Text Available Abstract Every year, many active fire spots are identified in the satellite images of the southern Brazilian grasslands in the Atlantic Forest biome and Pampa biome. Fire Radiative Power (FRP is a technique that uses remotely sensed data to quantify burned biomass. FRP measures the radiant energy released per time unit by burning vegetation. This study aims to use satellite and field data to estimate the biomass consumption rate and the biomass consumption coefficient for the southern Brazilian grasslands. Three fire points were identified in satellite FRP products. These data were combined with field data, collected through literature review, to calculate the biomass consumption coefficient. The type of vegetation is an important variable in the estimation of the biomass consumption coefficient. The biomass consumption rate was estimated to be 2.237 kg s-1 for the southern Brazilian grasslands in Atlantic Forest biome, and the biomass consumption coefficient was estimated to be 0.242 kg MJ-1.

  6. Temporal profiles of vegetation indices for characterizing grazing intensity on natural grasslands in Pampa biome

    Directory of Open Access Journals (Sweden)

    Amanda Heemann Junges

    2016-08-01

    Full Text Available ABSTRACT The Pampa biome is an important ecosystem in Brazil that is highly relevant to livestock production. The objective of this study was to analyze the potential use of vegetation indices to discriminate grazing intensities on natural grasslands in the Pampa biome. Moderate Resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI and Enhanced Vegetation Index (EVI images from Jan to Dec, 2000 to 2013 series, were analyzed for natural grassland experimental units managed under high (forage allowance of 5 ± 2 % live weight – LW, moderate (13 ± 5 % LW and low grazing intensity (19 ± 7 % LW. Regardless of intensity, the temporal profiles showed lower NDVI and EVI during winter, increased values in spring because of summer species regrowth, slightly decreased values in summer, especially in years when there is a water deficit, and increased values in the fall associated with the beginning of winter forage development. The average temporal profiles of moderate grazing intensity exhibited greater vegetation index values compared with low and high grazing intensities. The temporal profiles of less vegetation index were associated with lower green biomass accumulation caused by the negative impact of stocking rates on the leaf area index under high grazing intensity and a floristic composition with a predominance of tussocks under low grazing intensity. Vegetation indices can be used for distinguishing moderate grazing intensity from low and high intensities. The average EVI values can discriminate moderate grazing intensity during any season, and the NDVI values can discriminate moderate grazing intensity during spring and winter.

  7. Modeling the grazing effect on dry grassland carbon cycling with modified Biome-BGC grazing model

    Science.gov (United States)

    Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao

    2014-05-01

    Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC grazing model, we modeled carbon dynamics in Xinjiang for grasslands that varied in grazing intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of grazing on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when grazing intensity was lower than 0.40 head/ha. Grazing resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, grazing decreased vegetation C stock, while an increasing trend was observed with low grazing intensity. The soil C increased significantly (17%) with long-term grazing, while the soil C stock exhibited a steady trend without grazing. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the grazing systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how grazing impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past

  8. Ornamental Eudicotyledons from grasslands of Pampa biome in Rio Grande do Sul

    Directory of Open Access Journals (Sweden)

    Ana De Araújo Carrion

    2012-10-01

    Full Text Available The present study aims at investigating the group of Eudicotyledons native plants with ornamental potential of grasslands from the Pampa biome in the south of Brazil. The Pampa presents a high level of biodiversity; however, it requires studies related to the richness of vascular plants and its biological and ecological knowledge. The purpose of this work is to elaborate a preliminary inventory of this group of plants, analyzing the ornamental potential of each specie and indicating those that could be considered as being priorities for the purpose of sustainable use with this objective. Some grassland species were selected through the search for information in herbarium registers, national and international works about decorative plants, floristic surveys, besides the authors´ practical knowledge. Some parameters and values were associated, aiming at reducing the subjectivity of the choice. The survey resulted in a list of 177 species distributed in 36 families and 101 genera. Among these species, ten presented high ornamental potential. These data show that the richness of the grassland native ornamental flora is high, even though its use is poorly known. The use of these plants, if in a sustainable manner, can produce economic and ecological benefits.

  9. Biomes.

    Science.gov (United States)

    Web Feet K-8, 2001

    2001-01-01

    This annotated subject guide to Web sites and additional resources focuses on biomes. Specifies age levels for resources that include Web sites, CD-ROMs and software, videos, books, audios, and magazines; includes professional resources; and presents a relevant class activity. (LRW)

  10. Water balance in paired watersheds with eucalyptus and degraded grassland in Pampa biome

    Science.gov (United States)

    Rangelands of the Pampa biome, which cover regions of Argentina, Uruguay and Brazil (176,496 km2 – 2.07% of Brazilian territory and 63% of Rio Grande do Sul State territory, southern region of Brazil) in South America (total area of 750,000 km2), are being substituted by crops and commercial eucalyp...

  11. Guide to the literature on research in the grassland biome of South Africa

    CSIR Research Space (South Africa)

    Tainton, MN

    1984-12-01

    Full Text Available the development of an understanding of how these communities can best be managed to ensure their sustained producti¬vity, or indeed to increase their productivity. This publication serves to highlight the main work which has been undertaken in this biome...

  12. The southern Brazilian grassland biome: soil carbon stocks, fluxes of greenhouse gases and some options for mitigation.

    Science.gov (United States)

    Pillar, V D; Tornquist, C G; Bayer, C

    2012-08-01

    The southern Brazilian grassland biome contains highly diverse natural ecosystems that have been used for centuries for grazing livestock and that also provide other important environmental services. Here we outline the main factors controlling ecosystem processes, review and discuss the available data on soil carbon stocks and greenhouse gases emissions from soils, and suggest opportunities for mitigation of climatic change. The research on carbon and greenhouse gases emissions in these ecosystems is recent and the results are still fragmented. The available data indicate that the southern Brazilian natural grassland ecosystems under adequate management contain important stocks of organic carbon in the soil, and therefore their conservation is relevant for the mitigation of climate change. Furthermore, these ecosystems show a great and rapid loss of soil organic carbon when converted to crops based on conventional tillage practices. However, in the already converted areas there is potential to mitigate greenhouse gas emissions by using cropping systems based on no soil tillage and cover-crops, and the effect is mainly related to the potential of these crop systems to accumulate soil organic carbon in the soil at rates that surpass the increased soil nitrous oxide emissions. Further modelling with these results associated with geographic information systems could generate regional estimates of carbon balance.

  13. Are There Consistent Grazing Indicators in Drylands? Testing Plant Functional Types of Various Complexity in South Africa’s Grassland and Savanna Biomes

    Science.gov (United States)

    Linstädter, Anja; Schellberg, Jürgen; Brüser, Katharina; Moreno García, Cristian A.; Oomen, Roelof J.; du Preez, Chris C.; Ruppert, Jan C.; Ewert, Frank

    2014-01-01

    Despite our growing knowledge on plants’ functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa’s grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be

  14. Are there consistent grazing indicators in Drylands? Testing plant functional types of various complexity in South Africa's Grassland and Savanna Biomes.

    Directory of Open Access Journals (Sweden)

    Anja Linstädter

    Full Text Available Despite our growing knowledge on plants' functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa's grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs. Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses and two-trait PFTs (e.g. perennial grasses performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may

  15. Are there consistent grazing indicators in Drylands? Testing plant functional types of various complexity in South Africa's Grassland and Savanna Biomes.

    Science.gov (United States)

    Linstädter, Anja; Schellberg, Jürgen; Brüser, Katharina; Moreno García, Cristian A; Oomen, Roelof J; du Preez, Chris C; Ruppert, Jan C; Ewert, Frank

    2014-01-01

    Despite our growing knowledge on plants' functional responses to grazing, there is no consensus if an optimum level of functional aggregation exists for detecting grazing effects in drylands. With a comparative approach we searched for plant functional types (PFTs) with a consistent response to grazing across two areas differing in climatic aridity, situated in South Africa's grassland and savanna biomes. We aggregated herbaceous species into PFTs, using hierarchical combinations of traits (from single- to three-trait PFTs). Traits relate to life history, growth form and leaf width. We first confirmed that soil and grazing gradients were largely independent from each other, and then searched in each biome for PFTs with a sensitive response to grazing, avoiding confounding with soil conditions. We found no response consistency, but biome-specific optimum aggregation levels. Three-trait PFTs (e.g. broad-leaved perennial grasses) and two-trait PFTs (e.g. perennial grasses) performed best as indicators of grazing effects in the semi-arid grassland and in the arid savanna biome, respectively. Some PFTs increased with grazing pressure in the grassland, but decreased in the savanna. We applied biome-specific grazing indicators to evaluate if differences in grazing management related to land tenure (communal versus freehold) had effects on vegetation. Tenure effects were small, which we mainly attributed to large variability in grazing pressure across farms. We conclude that the striking lack of generalizable PFT responses to grazing is due to a convergence of aridity and grazing effects, and unlikely to be overcome by more refined classification approaches. Hence, PFTs with an opposite response to grazing in the two biomes rather have a unimodal response along a gradient of additive forces of aridity and grazing. The study advocates for hierarchical trait combinations to identify localized indicator sets for grazing effects. Its methodological approach may also be useful

  16. New phytotoxic diterpenoids from Vellozia gigantea (Velloziaceae), an endemic neotropical plant living in the endangered Brazilian biome Rupestrian grasslands

    Science.gov (United States)

    Vellozia gigantea is a rare, ancient and endemic neotropical plant present in the Brazilian Rupestrian grasslands. The dichloromethane extract of V. gigantea adventitious roots was phytotoxic against Lactuca sativa, Agrostis stolonifera and Lemna paucicostata, and showed larvicidal activity against ...

  17. The role of psychological factors in the adoption of improved natural grassland by Brazilian cattle farmers in Biome Pampa

    NARCIS (Netherlands)

    Rossi Borges, J.A.

    2015-01-01

    The objective of the research was to explore factors determining cattle farmers' intention to adopt improved natural grassland in Brazil. The research was carried out in the state of Rio Grande do Sul, in the south of Brazil.

  18. Satellite mapping of surface biophysical parameters at the biome scale over the North American grasslands: A case study

    Science.gov (United States)

    Wylie, B.K.; Meyer, D.J.; Tieszen, L.L.; Mannel, S.

    2002-01-01

    Quantification of biophysical parameters is needed by terrestrial process modeling and other applications. A study testing the role of multispectral data for monitoring biophysical parameters was conducted over a network of grassland field sites in the Great Plains of North America. Grassland biophysical parameters [leaf area index (LAI), fraction of absorbed photosynthetically active radiation (fPAR), and biomass] and their relationships with ground radiometer normalized difference vegetation index (NDVI) were established in this study (r2=.66–.85) from data collected across the central and northern Great Plains in 1995. These spectral/biophysical relationships were compared to 1996 field data from the Tallgrass Prairie Preserve in northeastern Oklahoma and showed no consistent biases, with most regression estimates falling within the respective 95% confidence intervals. Biophysical parameters were estimated for 21 “ground pixels” (grids) at the Tallgrass Prairie Preserve in 1996, representing three grazing/burning treatments. Each grid was 30×30 m in size and was systematically sampled with ground radiometer readings. The radiometric measurements were then converted to biophysical parameters and spatially interpolated using geostatistical kriging. Grid-based biophysical parameters were monitored through the growing season and regressed against Landsat Thematic Mapper (TM) NDVI (r2=.92–.94). These regression equations were used to estimate biophysical parameters for grassland TM pixels over the Tallgrass Prairie Preserve in 1996. This method maintained consistent regression development and prediction scales and attempted to minimize scaling problems associated with mixed land cover pixels. A method for scaling Landsat biophysical parameters to coarser resolution satellite data sets (1 km2) was also investigated.

  19. New Pesticidal Diterpenoids from Vellozia gigantea (Velloziaceae, an Endemic Neotropical Plant Living in the Endangered Brazilian Biome Rupestrian Grasslands

    Directory of Open Access Journals (Sweden)

    Mariana C. Ferreira

    2017-01-01

    Full Text Available Vellozia gigantea is a rare, ancient, and endemic neotropical plant present in the Brazilian Rupestrian grasslands. The dichloromethane extract of V. gigantea adventitious roots was phytotoxic against Lactuca sativa, Agrostis stolonifera, and Lemna paucicostata, and showed larvicidal activity against Aedes aegypti. Phytotoxicity bioassay-directed fractionation of the extract revealed one new isopimaradiene, 8(9,15-isopimaradien-1,3,7,11-tetraone, and three new cleistanthane diterpenoids, 7-oxo-8,11,13-cleistanthatrien-3-ol, 3,20-epoxy-7-oxo-8,11,13-cleistanthatrien-3-ol, and 20-nor-3,7-dioxo-1,8,11,13-cleistanthatetraen-10-ol. These new structures are proposed based on interpretation of 1H, 13C, COSY, NOESY, HSQC, and HMBC NMR data. 8(9,15-isopimaradien-1,3,7,11-tetraone was especially phytotoxic with an IC50 value (30 μM comparable to those of commercial herbicides clomazone, EPTC, and naptalam. In addition, 7-oxo-8,11,13-cleistanthatrien-3-ol provided 100% mortality at a concentration of 125 ppm against one-day-old Ae. aegypti larvae. Our results show that ancient and unique plants, like the endangered narrowly endemic neotropical species V. gigantea present in the Rupestrian grasslands, should also be protected because they can be sources of new bioactive compounds.

  20. A spatial implementation of the BIOME-BGC to model grassland GPP production and water budgets in the Ecuadorian Andean Region

    Science.gov (United States)

    Minaya, Veronica; Corzo, Gerald; van der Kwast, Johannes; Mynett, Arthur

    2016-04-01

    Many terrestrial biogeochemistry process models have been applied around the world at different scales and for a large range of ecosystems. Grasslands, and in particular the ones located in the Andean Region are essential ecosystems that sustain important ecological processes; however, just a few efforts have been made to estimate the gross primary production (GPP) and the hydrological budgets for this specific ecosystem along an altitudinal gradient. A previous study, which is one of the few available in the region, considered the heterogeneity of the main properties of the páramo vegetation and showed significant differences in plant functional types, site/soil parameters and daily meteorology. This study extends the work above mentioned and uses spatio-temporal analysis of the BIOME-BGC model results. This was done to simulate the GPP and the water fluxes in space and time, by applying altitudinal analysis. The catchment located at the southwestern slope of the Antisana volcano in Ecuador was selected as a representative area of the Andean páramos and its hydrological importance as one of the main sources of a water supply reservoir in the region. An accurate estimation of temporal changes in GPP in the region is important for carbon budget assessments, evaluation of the impact of climate change and biomass productivity. This complex and yet interesting problem was integrated by the ecosystem process model BIOME-BGC, the results were evaluated and associated to the land cover map where the growth forms of vegetation were identified. The responses of GPP and the water fluxes were not only dependent on the environmental drivers but also on the ecophysiology and the site specific parameters. The model estimated that the GPP at lower elevations doubles the amount estimated at higher elevations, which might have a large implication during extrapolations at larger spatio-temporal scales. The outcomes of the stand hydrological processes demonstrated a wrong

  1. Disturbance maintains alternative biome states.

    Science.gov (United States)

    Dantas, Vinícius de L; Hirota, Marina; Oliveira, Rafael S; Pausas, Juli G

    2016-01-01

    Understanding the mechanisms controlling the distribution of biomes remains a challenge. Although tropical biome distribution has traditionally been explained by climate and soil, contrasting vegetation types often occur as mosaics with sharp boundaries under very similar environmental conditions. While evidence suggests that these biomes are alternative states, empirical broad-scale support to this hypothesis is still lacking. Using community-level field data and a novel resource-niche overlap approach, we show that, for a wide range of environmental conditions, fire feedbacks maintain savannas and forests as alternative biome states in both the Neotropics and the Afrotropics. In addition, wooded grasslands and savannas occurred as alternative grassy states in the Afrotropics, depending on the relative importance of fire and herbivory feedbacks. These results are consistent with landscape scale evidence and suggest that disturbance is a general factor driving and maintaining alternative biome states and vegetation mosaics in the tropics. © 2015 John Wiley & Sons Ltd/CNRS.

  2. Changes in forest productivity across Alaska consistent with biome shift

    Science.gov (United States)

    Peter S.A. Beck; Glenn P. Juday; Claire Alix; Valerie A. Barber; Stephen E. Winslow; Emily E. Sousa; Patricia Heiser; James D. Herriges; Scott J. Goetz

    2011-01-01

    Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest...

  3. Monitoring in South African grasslands

    CSIR Research Space (South Africa)

    Mentis, MT

    1984-12-01

    Full Text Available The main purpose of this document is to propose how ecological monitoring might be developed in the Grassland Biome of South Africa. Monitoring is defined as the maintenance of regular surveillance to test the null hypothesis of no change...

  4. Changes in forest productivity across Alaska consistent with biome shift.

    Science.gov (United States)

    Beck, Pieter S A; Juday, Glenn P; Alix, Claire; Barber, Valerie A; Winslow, Stephen E; Sousa, Emily E; Heiser, Patricia; Herriges, James D; Goetz, Scott J

    2011-04-01

    Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline. © 2011 Blackwell Publishing Ltd/CNRS.

  5. Grassland Sustainability

    Science.gov (United States)

    Deborah U. Potter; Paulette L. Ford

    2004-01-01

    In this chapter we discuss grassland sustainability in the Southwest, grassland management for sustainability, national and local criteria and indicators of sustainable grassland ecosystems, and monitoring for sustainability at various scales. Ecological sustainability is defined as: [T]he maintenance or restoration of the composition, structure, and processes of...

  6. Dynamic vegetation modeling of tropical biomes during Heinrich events

    Science.gov (United States)

    Handiani, Dian Noor; Paul, André; Dupont, Lydie M.

    2010-05-01

    changed from warm temperate forest during the last glacial maximum to the grassland and dry shrubland, suggesting a drier climate during Heinrich event 1. In south-western Africa savanna and dry woodland changed into boreal forest and boreal-temperate forest suggesting wetter conditions. The biomes diagnosed from the control-run, were compared to the modern vegetation reconstruction of BIOME 4 (http://www.bridge.bris.ac.uk/resources/Databases/BIOMES_data). Consistent biome patterns were simulated for the tropical forests of western and south-western Africa and the grasslands of northern Africa. On the other hand, in southern Europe, where the BIOME 4 vegetation reconstruction is dominated by warm temperate and temperate forest, our model shows a strong bias towards the grassland.

  7. The Brazilian Pampa: A Fragile Biome

    Directory of Open Access Journals (Sweden)

    Valdir Marcos Stefenon

    2009-12-01

    Full Text Available Biodiversity is one of the most fundamental properties of Nature. It underpins the stability of ecosystems, provides vast bioresources for economic use, and has important cultural significance for many people. The Pampa biome, located in the southernmost state of Brazil, Rio Grande do Sul, illustrates the direct and indirect interdependence of humans and biodiversity. The Brazilian Pampa lies within the South Temperate Zone where grasslands scattered with shrubs and trees are the dominant vegetation. The soil, originating from sedimentary rocks, often has an extremely sandy texture that makes them fragile—highly prone to water and wind erosion. Human activities have converted or degraded many areas of this biome. In this review we discuss our state-of-the-art knowledge of the diversity and the major biological features of this regions and the cultural factors that have shaped it. Our aim is to contribute toward a better understanding of the current status of this special biome and to describe how the interaction between human activities and environment affects the region, highlighting the fragility of the Brazilian Pampa.

  8. Climate change in Inner Mongolia from 1955 to 2005-trends at regional, biome and local scales

    Energy Technology Data Exchange (ETDEWEB)

    Lu, N; Wilske, B; John, R; Chen, J [Department of Environmental Sciences, University of Toledo, Toledo, OH 43606 (United States); Ni, J, E-mail: nan.lu@utoledo.ed, E-mail: burkhard.wilske@utoledo.ed, E-mail: jni@ibcas.ac.c, E-mail: ranjeet.john@utoledo.ed, E-mail: jiquan.chen@utoledo.ed [Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam (Germany)

    2009-10-15

    This study investigated the climate change in Inner Mongolia based on 51 meteorological stations from 1955 to 2005. The climate data was analyzed at the regional, biome (i.e. forest, grassland and desert) and station scales, with the biome scale as our primary focus. The climate records showed trends of warmer and drier conditions in the region. The annual daily mean, maximum and minimum temperature increased whereas the diurnal temperature range (DTR) decreased. The decreasing trend of annual precipitation was not significant. However, the vapor pressure deficit (VPD) increased significantly. On the decadal scale, the warming and drying trends were more significant in the last 30 years than the preceding 20 years. The climate change varied among biomes, with more pronounced changes in the grassland and the desert biomes than in the forest biome. DTR and VPD showed the clearest inter-biome gradient from the lowest rate of change in the forest biome to the highest rate of change in the desert biome. The rates of change also showed large variations among the individual stations. Our findings correspond with the IPCC predictions that the future climate will vary significantly by location and through time, suggesting that adaptation strategies also need to be spatially viable.

  9. Climate change in Inner Mongolia from 1955 to 2005-trends at regional, biome and local scales

    International Nuclear Information System (INIS)

    Lu, N; Wilske, B; John, R; Chen, J; Ni, J

    2009-01-01

    This study investigated the climate change in Inner Mongolia based on 51 meteorological stations from 1955 to 2005. The climate data was analyzed at the regional, biome (i.e. forest, grassland and desert) and station scales, with the biome scale as our primary focus. The climate records showed trends of warmer and drier conditions in the region. The annual daily mean, maximum and minimum temperature increased whereas the diurnal temperature range (DTR) decreased. The decreasing trend of annual precipitation was not significant. However, the vapor pressure deficit (VPD) increased significantly. On the decadal scale, the warming and drying trends were more significant in the last 30 years than the preceding 20 years. The climate change varied among biomes, with more pronounced changes in the grassland and the desert biomes than in the forest biome. DTR and VPD showed the clearest inter-biome gradient from the lowest rate of change in the forest biome to the highest rate of change in the desert biome. The rates of change also showed large variations among the individual stations. Our findings correspond with the IPCC predictions that the future climate will vary significantly by location and through time, suggesting that adaptation strategies also need to be spatially viable.

  10. Biodiversity in temperate European grasslands: origin and conservation.

    OpenAIRE

    Pärtel, Meelis; Bruun, Hans Henrik; Sammul, Marek

    2005-01-01

    Northern Europe is in the forest zone, but wild megaherbivores have maintained grass-dominated vegetation here for the last 1.8 million years. Continuity of the grassland biome through glacialinterglacial cycles and connection to steppe vegetation has resulted in the evolution, immigration, and survival of a large number of grassland species. During the last millennia the effect of wild ungulates has been replaced by domestic grazers and hay making, and the persistence of grasslan...

  11. Identification of biomes affected by marginal expansion of agricultural land use induced by increased crop consumption

    DEFF Research Database (Denmark)

    Kløverpris, Jesper Hedal

    2009-01-01

    to characterise these areas. The present study ascribes so-called biomes (natural potential vegetation) to the areas affected by agricultural expansion in order to provide a basis for assessing the environmental impacts from land use in the life cycle impact assessment (LCIA). The methodology builds...... on agricultural statistics and maps of global agricultural areas and the global distribution of biomes. The application of the method is illustrated with four examples. The results indicate that agricultural expansion on land suited for crop cultivation (cultivable land) typically affects forest biomes...... or potential grassland/steppe, whereas expansion on land suited for grazing but not for crop cultivation (grazable land) typically occurs on potential shrubland or a few other biomes depending on the region. Some uncertainty applies to the results but it is concluded that it is feasible to identify biomes...

  12. The southern Brazilian grassland biome: soil carbon stocks, fluxes of greenhouse gases and some options for mitigation Campos do sul do Brasil: estoques de carbono no solo, fluxos de gases de efeito estufa e algumas opções para mitigação

    Directory of Open Access Journals (Sweden)

    VD Pillar

    2012-08-01

    Full Text Available The southern Brazilian grassland biome contains highly diverse natural ecosystems that have been used for centuries for grazing livestock and that also provide other important environmental services. Here we outline the main factors controlling ecosystem processes, review and discuss the available data on soil carbon stocks and greenhouse gases emissions from soils, and suggest opportunities for mitigation of climatic change. The research on carbon and greenhouse gases emissions in these ecosystems is recent and the results are still fragmented. The available data indicate that the southern Brazilian natural grassland ecosystems under adequate management contain important stocks of organic carbon in the soil, and therefore their conservation is relevant for the mitigation of climate change. Furthermore, these ecosystems show a great and rapid loss of soil organic carbon when converted to crops based on conventional tillage practices. However, in the already converted areas there is potential to mitigate greenhouse gas emissions by using cropping systems based on no soil tillage and cover-crops, and the effect is mainly related to the potential of these crop systems to accumulate soil organic carbon in the soil at rates that surpass the increased soil nitrous oxide emissions. Further modelling with these results associated with geographic information systems could generate regional estimates of carbon balance.Os campos do sul do Brasil são ecossistemas naturais com alta diversidade e têm sido há séculos importantes para a atividade pastoril e para outros importantes serviços ambientais. Este trabalho aponta os principais fatores que controlam os processos ecossistêmicos, revisa e discute os dados disponíveis sobre os estoques de carbono no solo e as emissões de gases de efeito estufa dos solos, e sugere oportunidades de mitigação das mudanças climáticas. A pesquisa sobre as emissões de carbono e gases de efeito estufa nos campos do

  13. Consequences of biome depletion

    International Nuclear Information System (INIS)

    Salvucci, Emiliano

    2013-01-01

    The human microbiome is an integral part of the superorganism together with their host and they have co-evolved since the early days of the existence of the human species. The modification of the microbiome as a result changes in food and social habits of human beings throughout their life history has led to the emergence of many diseases. In contrast with the Darwinian view of nature of selfishness and competence, new holistic approaches are rising. Under these views, the reconstitution of the microbiome comes out as a fundamental therapy for emerging diseases related to biome depletion.

  14. Modeling distribution of Schinus molle L. in the Brazilian Pampa: insights on vegetation dynamics and conservation of the biome

    Directory of Open Access Journals (Sweden)

    R.P.M. Lemos

    2014-12-01

    Full Text Available Natural establishment of forests in the Brazilian Pampa biome should occur due to soil, hydrology and climate conditions, although no significant forest expansion over grassland has been noticed, precluded mainly by human interference and lack of environmental management. In this study, we used niche-modeling distribution of the tree species Schinus molle L. based on climatic variables to access the vegetation dynamics of the Brazilian Pampa and to develop strategies that assure the conservation of this biome, concerning both grassland and forest formations. Here we show that a large area of the Brazilian Pampa is suitable for expansion of S. molle populations, supporting the forest expansion over grassland as a natural process in this biome. We propose that the current absence of tree species expansion over the grassland in these areas is a result of the resilience of the grassland and of human interferences through expansion of agriculture, ranching and forestry with exotic species. Therefore, conservationist actions should focus on establishing preservation unities that include forest populations and grassland, while environmental management should be applied just in farming areas with historical human interference. Such actions will respect the ecological dynamics of the Pampa and value the forest formations in this grassland-dominated environment.

  15. Evolution of the indoor biome.

    Science.gov (United States)

    Martin, Laura J; Adams, Rachel I; Bateman, Ashley; Bik, Holly M; Hawks, John; Hird, Sarah M; Hughes, David; Kembel, Steven W; Kinney, Kerry; Kolokotronis, Sergios-Orestis; Levy, Gabriel; McClain, Craig; Meadow, James F; Medina, Raul F; Mhuireach, Gwynne; Moreau, Corrie S; Munshi-South, Jason; Nichols, Lauren M; Palmer, Clare; Popova, Laura; Schal, Coby; Täubel, Martin; Trautwein, Michelle; Ugalde, Juan A; Dunn, Robert R

    2015-04-01

    Few biologists have studied the evolutionary processes at work in indoor environments. Yet indoor environments comprise approximately 0.5% of ice-free land area--an area as large as the subtropical coniferous forest biome. Here we review the emerging subfield of 'indoor biome' studies. After defining the indoor biome and tracing its deep history, we discuss some of its evolutionary dimensions. We restrict our examples to the species found in human houses--a subset of the environments constituting the indoor biome--and offer preliminary hypotheses to advance the study of indoor evolution. Studies of the indoor biome are situated at the intersection of evolutionary ecology, anthropology, architecture, and human ecology and are well suited for citizen science projects, public outreach, and large-scale international collaborations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Using the theory of planned behavior to identify key beliefs underlying Brazilian cattle farmers' intention to use improved natural grassland

    NARCIS (Netherlands)

    Rossi Borges, Joao; Tauer, Loren Willian; Oude Lansink, Alfons

    2016-01-01

    In biome Pampa, Brazil, cattle farmers have managed the natural grasslands using practices that result in overgrazing, low productivity and low farm income. In addition, farmers in the region converted natural grasslands from beef production to more profitable activities, such as cash crops. This

  17. Biomes computed from simulated climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Claussen, M.; Esch, M. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

    1994-01-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study undertaken in order to show the advantage of this biome model in diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to in simulated rainfall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are for the tropical rain forests. A potential northeast shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting chances in vegetation patterns due to a rapid climate change, the latter simulation to be taken as a prediction of chances in conditions favourable for the existence of certain biomes, not as a reduction of a future distribution of biomes. 15 refs., 8 figs., 2 tabs.

  18. Biomes computed from simulated climatologies

    Energy Technology Data Exchange (ETDEWEB)

    Claussen, W.; Esch, M.

    1992-09-01

    The biome model of Prentice et al. is used to predict global patterns of potential natural plant formations, or biomes, from climatologies simulated by ECHAM, a model used for climate simulations at the Max-Planck-Institut fuer Meteorologie. This study is undertaken in order to show the advantage of this biome model in comprehensively diagnosing the performance of a climate model and assessing effects of past and future climate changes predicted by a climate model. Good overall agreement is found between global patterns of biomes computed from observed and simulated data of present climate. But there are also major discrepancies indicated by a difference in biomes in Australia, in the Kalahari Desert, and in the Middle West of North America. These discrepancies can be traced back to failures in simulated rain fall as well as summer or winter temperatures. Global patterns of biomes computed from an ice age simulation reveal that North America, Europe, and Siberia should have been covered largely by tundra and taiga, whereas only small differences are seen for the tropical rain forests. A potential North-East shift of biomes is expected from a simulation with enhanced CO{sub 2} concentration according to the IPCC Scenario A. Little change is seen in the tropical rain forest and the Sahara. Since the biome model used is not capable of predicting changes in vegetation patterns due to a rapid climate change, the latter simulation has to be taken as a prediction of changes in conditions favorable for the existence of certain biomes, not as a prediction of a future distribution of biomes. (orig.).

  19. The deforestation story: testing for anthropogenic origins of Africa's flammable grassy biomes.

    Science.gov (United States)

    Bond, William; Zaloumis, Nicholas P

    2016-06-05

    Africa has the most extensive C4 grassy biomes of any continent. They are highly flammable accounting for greater than 70% of the world's burnt area. Much of Africa's savannas and grasslands occur in climates warm enough and wet enough to support closed forests. The combination of open grassy systems and the frequent fires they support have long been interpreted as anthropogenic artefacts caused by humans igniting frequent fires. True grasslands, it was believed, would be restricted to climates too dry or too cold to support closed woody vegetation. The idea that higher-rainfall savannas are anthropogenic and that fires are of human origin has led to initiatives to 'reforest' Africa's open grassy systems paid for by carbon credits under the assumption that the net effect of converting these system to forests would sequester carbon, reduce greenhouse gases and mitigate global warming. This paper reviews evidence for the antiquity of African grassy ecosystems and for the fires that they sustain. Africa's grassy biomes and the fires that maintain them are ancient and there is no support for the idea that humans caused large-scale deforestation. Indicators of old-growth grasslands are described. These can help distinguish secondary grasslands suitable for reforestation from ancient grasslands that should not be afforested.This article is part of the themed issue 'The interaction of fire and mankind'. © 2016 The Author(s).

  20. Description of the Karoo Biome project

    CSIR Research Space (South Africa)

    Cowling, RM

    1986-01-01

    Full Text Available The ecological characteristics and ecological problems of the karoo biome are briefly described. A conceptual basis and guidelines for the development of the Karoo Biome Project are outlined by addressing project goals, project structure...

  1. Effects of temperature and precipitation on grassland bird nesting success as mediated by patch size.

    Science.gov (United States)

    Zuckerberg, Benjamin; Ribic, Christine A; McCauley, Lisa A

    2018-02-06

    Grassland birds are declining faster than any other bird guild across North America. Shrinking ranges and population declines are attributed to widespread habitat loss and increasingly fragmented landscapes of agriculture and other land uses that are misaligned with grassland bird conservation. Concurrent with habitat loss and degradation, temperate grasslands have been disproportionally affected by climate change relative to most other terrestrial biomes. Distributions of grassland birds often correlate with gradients in climate, but few researchers have explored the consequences of weather on the demography of grassland birds inhabiting a range of grassland fragments. To do so, we modeled the effects of temperature and precipitation on nesting success rates of 12 grassland bird species inhabiting a range of grassland patches across North America (21,000 nests from 81 individual studies). Higher amounts of precipitation in the preceding year were associated with higher nesting success, but wetter conditions during the active breeding season reduced nesting success. Extremely cold or hot conditions during the early breeding season were associated with lower rates of nesting success. The direct and indirect influence of temperature and precipitation on nesting success was moderated by grassland patch size. The positive effects of precipitation in the preceding year on nesting success were strongest in relatively small grassland patches and had little effect in large patches. Conversely, warm temperatures reduced nesting success in small grassland patches but increased nesting success in large patches. Mechanisms underlying these differences may be patch-size-induced variation in microclimates and predator activity. Although the exact cause is unclear, large grassland patches, the most common metric of grassland conservation, appears to moderate the effects of weather on grassland-bird demography and could be an effective component of climate-change adaptation.

  2. Expanding the global network of protected areas to save the imperiled mediterranean biome.

    Science.gov (United States)

    Underwood, Emma C; Klausmeyer, Kirk R; Cox, Robin L; Busby, Sylvia M; Morrison, Scott A; Shaw, M Rebecca

    2009-02-01

    : Global goals established by the Convention on Biological Diversity stipulate that 10% of the world's ecological regions must be effectively conserved by 2010. To meet that goal for the mediterranean biome, at least 5% more land must be formally protected over the next few years. Although global assessments identify the mediterranean biome as a priority, without biologically meaningful analysis units, finer-resolution data, and corresponding prioritization analysis, future conservation investments could lead to more area being protected without increasing the representation of unique mediterranean ecosystems. We used standardized analysis units and six potential natural vegetation types stratified by 3 elevation zones in a global gap analysis that systematically explored conservation priorities across the mediterranean biome. The highest levels of protection were in Australia, South Africa, and California-Baja California (from 9-11%), and the lowest levels of protection were in Chile and the mediterranean Basin (biome only one of the six vegetation types--mediterranean shrubland--exceeded 10% protection. The remaining vegetation types--grassland, scrub, succulent dominated, woodland, and forest--each had biome, we identified biodiversity assemblages with 30% conversion and suggest that these assemblages be elevated to high-priority status in future conservation efforts.

  3. Terrestrial ecosystem process model Biome-BGCMuSo v4.0: summary of improvements and new modeling possibilities

    Science.gov (United States)

    Hidy, Dóra; Barcza, Zoltán; Marjanović, Hrvoje; Zorana Ostrogović Sever, Maša; Dobor, Laura; Gelybó, Györgyi; Fodor, Nándor; Pintér, Krisztina; Churkina, Galina; Running, Steven; Thornton, Peter; Bellocchi, Gianni; Haszpra, László; Horváth, Ferenc; Suyker, Andrew; Nagy, Zoltán

    2016-12-01

    The process-based biogeochemical model Biome-BGC was enhanced to improve its ability to simulate carbon, nitrogen, and water cycles of various terrestrial ecosystems under contrasting management activities. Biome-BGC version 4.1.1 was used as a base model. Improvements included addition of new modules such as the multilayer soil module, implementation of processes related to soil moisture and nitrogen balance, soil-moisture-related plant senescence, and phenological development. Vegetation management modules with annually varying options were also implemented to simulate management practices of grasslands (mowing, grazing), croplands (ploughing, fertilizer application, planting, harvesting), and forests (thinning). New carbon and nitrogen pools have been defined to simulate yield and soft stem development of herbaceous ecosystems. The model version containing all developments is referred to as Biome-BGCMuSo (Biome-BGC with multilayer soil module; in this paper, Biome-BGCMuSo v4.0 is documented). Case studies on a managed forest, cropland, and grassland are presented to demonstrate the effect of model developments on the simulation of plant growth as well as on carbon and water balance.

  4. Biosphere 2's Marsh Biome

    Science.gov (United States)

    Molnar, Jennifer; Goodridge, Kelven

    1997-01-01

    The Marsh Biome, which was modeled after the mangroves and marshes of southwest Florida, has an area of 441.2 sq m separated into three hydrologically independent sections: the Freshwater, Oligohaline and Salt Marshes. The divisions are made based on their salinity (approximately 0, 4, and 34 ppt. respectively), but they also contain different biological communities. The Freshwater and Oligohaline Marshes are mostly filled with various grasses and several trees, while the Salt Marsh houses regions of red, black, and white mangroves (Rhizophora mangle, Avicennia germinans, and Languncularia racemosa respectively). Overall, there are an estimated 80 species of plants within the biome. Water in the Salt Marsh follows a meandering stream from the algal turf scrubbers (apparatuses that clean the water of its nutrients and heavy metals while increasing dissolved oxygen levels) which have an outlet in the Salt Marsh section near sites 4 and 5 to the Fringing Red Mangrove section. The sections of the Salt Marsh are separated by walls of concrete with openings to allow the stream to flow through. Throughout this study, conducted through the months of June and July, many conditions within the biome remained fairly constant. The temperature was within a degree or two of 25 C, mostly depending on whether the sample site was in direct sunlight or shaded. The pH throughout the Salt Marsh was 8.0 +/- 0.2, and the lower salinity waters only dropped below this soon after rains. The water rdepth and dissolved oxygen varied, however, between sites.

  5. The California Valley grassland

    Science.gov (United States)

    Keeley, J.E.; Schoenherr, Allan A.

    1990-01-01

    Grasslands are distributed throughout California from Oregon to Baja California Norte and from the coast to the desert (Brown 1982) (Figure 1). This review will focus on the dominant formation in cismontane California, a community referred to as Valley Grassland (Munz 1959). Today, Valley Grassland is dominated by non-native annual grasses in genera such as Avena (wild oat), Bromus (brome grass), and Hordeum (barley), and is often referred to as the California annual grassland. On localized sites, native perennial bunchgrasses such as Stipa pultra (purple needle grass) may dominate and such sites are interpreted to be remnants of the pristine valley grassland. In northwestern California a floristically distinct formation of the Valley Grassland, known as Coast Prairie (Munz 1959) or Northern Coastal Grassland (Holland and Keil 1989) is recognized. The dominant grasses include many native perennial bunchgrasses in genera such as Agrostis, Calamagrostis, Danthonia, Deschampsia, Festuca, Koeleria and Poa (Heady et al. 1977). Non-native annuals do not dominate, but on some sites non-native perennials like Anthoxanthum odoratum may colonize the native grassland (Foin and Hektner 1986). Elevationally, California's grasslands extend from sea level to at leas 1500 m. The upper boundary is vague because montane grassland formations are commonly referred to as meadows; a community which Munz (1959) does not recognize. Holland and Keil (1989) describe the montane meadow as an azonal community; that is, a community restricted not so much to a particular climatic zone but rather controlled by substrate characteristics. They consider poor soil-drainage an over-riding factor in the development of montane meadows and, in contrast to grasslands, meadows often remain green through the summer drought. Floristically, meadows are composed of graminoids; Cyperaceae, Juncaceae, and rhizomatous grasses such as Agropyron (wheat grass). Some bunchgrasses, such as Muhlenbergia rigens, are

  6. Integrating Taxonomic, Functional and Phylogenetic Beta Diversities: Interactive Effects with the Biome and Land Use across Taxa.

    Science.gov (United States)

    Corbelli, Julian Martin; Zurita, Gustavo Andres; Filloy, Julieta; Galvis, Juan Pablo; Vespa, Natalia Isabel; Bellocq, Isabel

    2015-01-01

    The spatial distribution of species, functional traits and phylogenetic relationships at both the regional and local scales provide complementary approaches to study patterns of biodiversity and help to untangle the mechanisms driving community assembly. Few studies have simultaneously considered the taxonomic (TBD), functional (FBD) and phylogenetic (PBD) facets of beta diversity. Here we analyze the associations between TBD, FBD, and PBD with the biome (representing different regional species pools) and land use, and investigate whether TBD, FBD and PBD were correlated. In the study design we considered two widely used indicator taxa (birds and ants) from two contrasting biomes (subtropical forest and grassland) and land uses (tree plantations and cropfields) in the southern Neotropics. Non-metric multidimensional scaling showed that taxonomic, functional and phylogenetic distances were associated to biome and land use; study sites grouped into four groups on the bi-dimensional space (cropfields in forest and grassland, and tree plantations in forest and grassland), and that was consistent across beta diversity facets and taxa. Mantel and PERMANOVA tests showed that TBD, FBD and PBD were positively correlated for both bird and ant assemblages; in general, partial correlations were also significant. Some of the functional traits considered here were conserved along phylogeny. Our results will contribute to the development of sound land use planning and beta diversity conservation.

  7. Integrating Taxonomic, Functional and Phylogenetic Beta Diversities: Interactive Effects with the Biome and Land Use across Taxa

    Science.gov (United States)

    Corbelli, Julian Martin; Zurita, Gustavo Andres; Filloy, Julieta; Galvis, Juan Pablo; Vespa, Natalia Isabel; Bellocq, Isabel

    2015-01-01

    The spatial distribution of species, functional traits and phylogenetic relationships at both the regional and local scales provide complementary approaches to study patterns of biodiversity and help to untangle the mechanisms driving community assembly. Few studies have simultaneously considered the taxonomic (TBD), functional (FBD) and phylogenetic (PBD) facets of beta diversity. Here we analyze the associations between TBD, FBD, and PBD with the biome (representing different regional species pools) and land use, and investigate whether TBD, FBD and PBD were correlated. In the study design we considered two widely used indicator taxa (birds and ants) from two contrasting biomes (subtropical forest and grassland) and land uses (tree plantations and cropfields) in the southern Neotropics. Non-metric multidimensional scaling showed that taxonomic, functional and phylogenetic distances were associated to biome and land use; study sites grouped into four groups on the bi-dimensional space (cropfields in forest and grassland, and tree plantations in forest and grassland), and that was consistent across beta diversity facets and taxa. Mantel and PERMANOVA tests showed that TBD, FBD and PBD were positively correlated for both bird and ant assemblages; in general, partial correlations were also significant. Some of the functional traits considered here were conserved along phylogeny. Our results will contribute to the development of sound land use planning and beta diversity conservation. PMID:25978319

  8. Integrating Taxonomic, Functional and Phylogenetic Beta Diversities: Interactive Effects with the Biome and Land Use across Taxa.

    Directory of Open Access Journals (Sweden)

    Julian Martin Corbelli

    Full Text Available The spatial distribution of species, functional traits and phylogenetic relationships at both the regional and local scales provide complementary approaches to study patterns of biodiversity and help to untangle the mechanisms driving community assembly. Few studies have simultaneously considered the taxonomic (TBD, functional (FBD and phylogenetic (PBD facets of beta diversity. Here we analyze the associations between TBD, FBD, and PBD with the biome (representing different regional species pools and land use, and investigate whether TBD, FBD and PBD were correlated. In the study design we considered two widely used indicator taxa (birds and ants from two contrasting biomes (subtropical forest and grassland and land uses (tree plantations and cropfields in the southern Neotropics. Non-metric multidimensional scaling showed that taxonomic, functional and phylogenetic distances were associated to biome and land use; study sites grouped into four groups on the bi-dimensional space (cropfields in forest and grassland, and tree plantations in forest and grassland, and that was consistent across beta diversity facets and taxa. Mantel and PERMANOVA tests showed that TBD, FBD and PBD were positively correlated for both bird and ant assemblages; in general, partial correlations were also significant. Some of the functional traits considered here were conserved along phylogeny. Our results will contribute to the development of sound land use planning and beta diversity conservation.

  9. Phylogenetic biome conservatism on a global scale.

    Science.gov (United States)

    Crisp, Michael D; Arroyo, Mary T K; Cook, Lyn G; Gandolfo, Maria A; Jordan, Gregory J; McGlone, Matt S; Weston, Peter H; Westoby, Mark; Wilf, Peter; Linder, H Peter

    2009-04-09

    How and why organisms are distributed as they are has long intrigued evolutionary biologists. The tendency for species to retain their ancestral ecology has been demonstrated in distributions on local and regional scales, but the extent of ecological conservatism over tens of millions of years and across continents has not been assessed. Here we show that biome stasis at speciation has outweighed biome shifts by a ratio of more than 25:1, by inferring ancestral biomes for an ecologically diverse sample of more than 11,000 plant species from around the Southern Hemisphere. Stasis was also prevalent in transocean colonizations. Availability of a suitable biome could have substantially influenced which lineages establish on more than one landmass, in addition to the influence of the rarity of the dispersal events themselves. Conversely, the taxonomic composition of biomes has probably been strongly influenced by the rarity of species' transitions between biomes. This study has implications for the future because if clades have inherently limited capacity to shift biomes, then their evolutionary potential could be strongly compromised by biome contraction as climate changes.

  10. A biome-scale assessment of the impact of invasive alien plants on ecosystem services in South Africa.

    Science.gov (United States)

    van Wilgen, B W; Reyers, B; Le Maitre, D C; Richardson, D M; Schonegevel, L

    2008-12-01

    This paper reports an assessment of the current and potential impacts of invasive alien plants on selected ecosystem services in South Africa. We used data on the current and potential future distribution of 56 invasive alien plant species to estimate their impact on four services (surface water runoff, groundwater recharge, livestock production and biodiversity) in five terrestrial biomes. The estimated reductions in surface water runoff as a result of current invasions were >3000 million m(3) (about 7% of the national total), most of which is from the fynbos (shrubland) and grassland biomes; the potential reductions would be more than eight times greater if invasive alien plants were to occupy the full extent of their potential range. Impacts on groundwater recharge would be less severe, potentially amounting to approximately 1.5% of the estimated maximum reductions in surface water runoff. Reductions in grazing capacity as a result of current levels of invasion amounted to just over 1% of the potential number of livestock that could be supported. However, future impacts could increase to 71%. A 'biodiversity intactness index' (the remaining proportion of pre-modern populations) ranged from 89% to 71% for the five biomes. With the exception of the fynbos biome, current invasions have almost no impact on biodiversity intactness. Under future levels of invasion, however, these intactness values decrease to around 30% for the savanna, fynbos and grassland biomes, but to even lower values (13% and 4%) for the two karoo biomes. Thus, while the current impacts of invasive alien plants are relatively low (with the exception of those on surface water runoff), the future impacts could be very high. While the errors in these estimates are likely to be substantial, the predicted impacts are sufficiently large to suggest that there is serious cause for concern.

  11. 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

  12. Woodland expansion in South African grassy biomes based on satellite observations (1990-2013): general patterns and potential drivers.

    Science.gov (United States)

    Skowno, Andrew L; Thompson, Mark W; Hiestermann, Jens; Ripley, Brad; West, Adam G; Bond, William J

    2017-06-01

    Increases in woody plant cover in savanna grassland environments have been reported on globally for over 50 years and are generally perceived as a threat to rangeland productivity and biodiversity. Despite this, few attempts have been made to estimate the extent of woodland increase at a national scale, principally due to technical constraints such as availability of appropriate remote sensing products. In this study, we aimed to measure the extent to which woodlands have replaced grasslands in South Africa's grassy biomes. We use multiseason Landsat data in conjunction with satellite L-band radar backscatter data to estimate the extent of woodlands and grasslands in 1990 and 2013. The method employed allows for a unique, nationwide measurement of transitions between grassland and woodland classes in recent decades. We estimate that during the 23-year study period, woodlands have replaced grasslands over ~57 000 km 2 and conversely that grasslands have replaced woodlands over ~30 000 km 2 , a net increase in the extent of woodland of ~27 000 km 2 and an annual increase of 0.22%. The changes varied markedly across the country; areas receiving over 500 mm mean annual precipitation showed higher rates of woodland expansion than regions receiving 0.19% yr -1 ). The woodland change map presented here provides a unique opportunity to test the numerous models of woody plant encroachment at a national/regional scale. © 2016 John Wiley & Sons Ltd.

  13. Description of the Fynbos Biome Project

    CSIR Research Space (South Africa)

    Kruger, FJ

    1978-06-01

    Full Text Available The objectives, organization and research programme of the Fynbos Biome Project being undertaken in the south-west and southern Cape are described. The project is a cooperative multi-disciplinary study of the ecological characteristics, structure...

  14. Thresholds for boreal biome transitions.

    Science.gov (United States)

    Scheffer, Marten; Hirota, Marina; Holmgren, Milena; Van Nes, Egbert H; Chapin, F Stuart

    2012-12-26

    Although the boreal region is warming twice as fast as the global average, the way in which the vast boreal forests and tundras may respond is poorly understood. Using satellite data, we reveal marked alternative modes in the frequency distributions of boreal tree cover. At the northern end and at the dry continental southern extremes, treeless tundra and steppe, respectively, are the only possible states. However, over a broad intermediate temperature range, these treeless states coexist with boreal forest (∼75% tree cover) and with two more open woodland states (∼20% and ∼45% tree cover). Intermediate tree covers (e.g., ∼10%, ∼30%, and ∼60% tree cover) between these distinct states are relatively rare, suggesting that they may represent unstable states where the system dwells only transiently. Mechanisms for such instabilities remain to be unraveled, but our results have important implications for the anticipated response of these ecosystems to climatic change. The data reveal that boreal forest shows no gradual decline in tree cover toward its limits. Instead, our analysis suggests that it becomes less resilient in the sense that it may more easily shift into a sparse woodland or treeless state. Similarly, the relative scarcity of the intermediate ∼10% tree cover suggests that tundra may shift relatively abruptly to a more abundant tree cover. If our inferences are correct, climate change may invoke massive nonlinear shifts in boreal biomes.

  15. Temporal Changes in Coupled Vegetation Phenology and Productivity are Biome-Specific in the Northern Hemisphere

    Directory of Open Access Journals (Sweden)

    Lanhui Wang

    2017-12-01

    Full Text Available Global warming has greatly stimulated vegetation growth through both extending the growing season and promoting photosynthesis in the Northern Hemisphere (NH. Analyzing the combined dynamics of such trends can potentially improve our current understanding on changes in vegetation functioning and the complex relationship between anthropogenic and climatic drivers. This study aims to analyze the relationships (long-term trends and correlations of length of vegetation growing season (LOS and vegetation productivity assessed by the growing season NDVI integral (GSI in the NH (>30°N to study any dependency of major biomes that are characterized by different imprint from anthropogenic influence. Spatial patterns of converging/diverging trends in LOS and GSI and temporal changes in the coupling between LOS and GSI are analyzed for major biomes at hemispheric and continental scales from the third generation Global Inventory Monitoring and Modeling Studies (GIMMS Normalized Difference Vegetation Index (NDVI dataset for a 32-year period (1982–2013. A quarter area of the NH is covered by converging trends (consistent significant trends in LOS and GSI, whereas diverging trends (opposing significant trends in LOS and GSI cover about 6% of the region. Diverging trends are observed mainly in high latitudes and arid/semi-arid areas of non-forest biomes (shrublands, savannas, and grasslands, whereas forest biomes and croplands are primarily characterized by converging trends. The study shows spatially-distinct and biome-specific patterns between the continental land masses of Eurasia (EA and North America (NA. Finally, areas of high positive correlation between LOS and GSI showed to increase during the period of analysis, with areas of significant positive trends in correlation being more widespread in NA as compared to EA. The temporal changes in the coupled vegetation phenology and productivity suggest complex relationships and interactions that are induced

  16. The extent of forest in dryland biomes

    Science.gov (United States)

    Jean-Francois Bastin; Nora Berrahmouni; Alan Grainger; Danae Maniatis; Danilo Mollicone; Rebecca Moore; Chiara Patriarca; Nicolas Picard; Ben Sparrow; Elena Maria Abraham; Kamel Aloui; Ayhan Atesoglu; Fabio Attore; Caglar Bassullu; Adia Bey; Monica Garzuglia; Luis G. GarcÌa-Montero; Nikee Groot; Greg Guerin; Lars Laestadius; Andrew J. Lowe; Bako Mamane; Giulio Marchi; Paul Patterson; Marcelo Rezende; Stefano Ricci; Ignacio Salcedo; Alfonso Sanchez-Paus Diaz; Fred Stolle; Venera Surappaeva; Rene Castro

    2017-01-01

    Dryland biomes cover two-fifths of Earth’s land surface, but their forest area is poorly known. Here, we report an estimate of global forest extent in dryland biomes, based on analyzing more than 210,000 0.5-hectare sample plots through a photo-interpretation approach using large databases of satellite imagery at (i) very high spatial resolution and (ii) very high...

  17. Determining the resilience of carbon dynamics in semi-arid biomes of the Southwestern US to severe drought and altered rainfall patterns

    Science.gov (United States)

    Litvak, M. E.; Krofcheck, D. J.; Hilton, T. W.; Fox, A. M.; Osuna, J. L.

    2011-12-01

    Water is critically important for biotic processes in semi-arid ecosystems and 2011 is developing as one of the most severe drought years on record for many parts of the Southwestern US. To quantify the impact of this severe drought on regional carbon and energy balance, we need a more detailed understanding of how water limitation alters ecosystem processes across a range of semi-arid biomes. We quantified the impact of severe drought and changes in both the quantity and distribution of precipitation on ecosystem biotic structure and function across the range of biomes represented in the NM elevation gradient network (desert grassland, creosote shrubland, juniper savanna, piñon-juniper woodland, ponderosa pine forest and subalpine mixed conifer forest). We compared how daily, seasonal and annual carbon and energy balance and their components in each of these biomes respond to changes in rainfall patterns using continuous measurements of carbon, water and energy exchange and associated measurements in each of these biomes during a 5 year period (2006-2011) that included a severe drought, and large variability in both winter precipitation and the timing and intensity of the monsoon. To understand the underlying mechanisms, we used time series of radiation absorbed by vegetation, surface albedo, soil moisture storage, phenology, gross primary productivity (GPP), ecosystem respiration (Re), and WorldView-2 images acquired pre- and post-monsoon in each of these biomes. In all of the biomes except the desert grassland site, the strength and timing of both winter and monsoon precipitation are important controls over carbon and energy dynamics in this region, though we see site-specific sensitivities across the elevation gradient. Over the past 5 years, carbon dynamics in the desert grassland site appears to be decoupled from winter precipitation. In addition, carbon dynamics in disturbed grassland and pinon-juniper ecosystems were more sensitive to severe drought than

  18. Grassland Aboveground Biomass in Inner Mongolia: Dynamics (2001-2016) and Driving force

    Science.gov (United States)

    Li, F.; Zeng, Y.; Chen, J.; Wu, B.

    2017-12-01

    Plant biomass is the most critical measure of carbon stored in an ecosystem, yet it remains imprecisely modeled for many terrestrial biomes. This lack of modeling capacity for biomass and its change through time and space has impeded scientists from making headway concerning issues in the geographic and social sciences. Satellite remote sensing techniques excel at detecting changes in the Earth's surface; however, accurate estimates of biomass for the heterogeneous biome landscapes based on remote sensing techniques are few and far between, which has led to many repetitive studies. Here, we argued that our ability to assess biomass in a heterogeneous landscape using satellite remote sensing techniques would be effectively enhanced through a stratification of landscapes, i.e homogenizing landscapes. Specifically, above-ground biomass (AGB) for an extended heterogeneous grassland biome over the entirety of Inner Mongolia during the past 16 years (2001-2016) was explored using remote sensing time series data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Massive and extensive in-situ measurement AGB data and pure vegetation index (PVI) models, developed from normal remote sensing vegetation indices such as the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI), were highlighted in the accomplishment of this study. Taking into full consideration the landscape heterogeneity for the grassland biome over Inner Mongolia, we achieved a series of AGB models with high R2 (>0.85) and low RMSE ( 20.85 g/m2). The total average amount of fresh AGB for the entirety of Inner Mongolia grasslands over the past 16 years was estimated as 87 Tg with an inter-annual standard deviation of 9 Tg. Overall, the grassland AGB for Inner Mongolia increased sporadically. We found that the dynamics of AGB in the grassland biome of Inner Mongolia were substantially dominated by variation in precipitation despite the accommodation of a huge

  19. Intrinsic climate dependency of ecosystem light and water-use-efficiencies across Australian biomes

    International Nuclear Information System (INIS)

    Shi, Hao; Li, Longhui; Eamus, Derek; Cleverly, James; Huete, Alfredo; Yu, Qiang; Beringer, Jason; Van Gorsel, Eva; Hutley, Lindsay

    2014-01-01

    The sensitivity of ecosystem gross primary production (GPP) to availability of water and photosynthetically active radiation (PAR) differs among biomes. Here we investigated variations of ecosystem light-use-efficiency (eLUE: GPP/PAR) and water-use-efficiency (eWUE: GPP/evapotranspiration) among seven Australian eddy covariance sites with differing annual precipitation, species composition and temperature. Changes to both eLUE and eWUE were primarily correlated with atmospheric vapor pressure deficit (VPD) at multiple temporal scales across biomes, with minor additional correlations observed with soil moisture and temperature. The effects of leaf area index on eLUE and eWUE were also relatively weak compared to VPD, indicating an intrinsic dependency of eLUE and eWUE on climate. Additionally, eLUE and eWUE were statistically different for biomes between summer and winter, except eWUE for savannas and the grassland. These findings will improve our understanding of how light- and water-use traits in Australian ecosystems may respond to climate change. (letter)

  20. The future distribution of the savannah biome: model-based and biogeographic contingency.

    Science.gov (United States)

    Moncrieff, Glenn R; Scheiter, Simon; Langan, Liam; Trabucco, Antonio; Higgins, Steven I

    2016-09-19

    The extent of the savannah biome is expected to be profoundly altered by climatic change and increasing atmospheric CO2 concentrations. Contrasting projections are given when using different modelling approaches to estimate future distributions. Furthermore, biogeographic variation within savannahs in plant function and structure is expected to lead to divergent responses to global change. Hence the use of a single model with a single savannah tree type will likely lead to biased projections. Here we compare and contrast projections of South American, African and Australian savannah distributions from the physiologically based Thornley transport resistance statistical distribution model (TTR-SDM)-and three versions of a dynamic vegetation model (DVM) designed and parametrized separately for specific continents. We show that attempting to extrapolate any continent-specific model globally biases projections. By 2070, all DVMs generally project a decrease in the extent of savannahs at their boundary with forests, whereas the TTR-SDM projects a decrease in savannahs at their boundary with aridlands and grasslands. This difference is driven by forest and woodland expansion in response to rising atmospheric CO2 concentrations in DVMs, unaccounted for by the TTR-SDM. We suggest that the most suitable models of the savannah biome for future development are individual-based dynamic vegetation models designed for specific biogeographic regions.This article is part of the themed issue 'Tropical grassy biomes: linking ecology, human use and conservation'. © 2016 The Author(s).

  1. Modelling the impacts of reoccurring fires in tropical savannahs using Biome-BGC.

    Science.gov (United States)

    Fletcher, Charlotte; Petritsch, Richard; Pietsch, Stephan

    2010-05-01

    Fires are a dominant feature of tropical savannahs and have occurred throughout history by natural as well as human-induced means. These fires have a profound influence on the landscape in terms of flux dynamics and vegetative species composition. This study attempts to understand the impacts of fire regimes on flux dynamics and vegetation composition in savannahs using the Biome-BGC model. The Batéké Plateau, Gabon - an area of savannah grasslands in the Congo basin, serves as a case-study. To achieve model validation for savannahs, data sets from stands with differing levels of past burning are used. It is hypothesised that the field measurements from those stands with lower-levels of past burning will correlate with the Biome-BGC model output, meaning that the model is validated for the savannah excluding fire regimes. However, in reality, fire is frequent in the savannah. Data on past fire events are available from the Moderate Resolution Imaging Spectroradiometer (MODIS) to provide the fire regimes of the model. As the field data-driven measurements of the burnt stands are influenced by fire in the savannah, this will therefore result in a Biome-BGC model validated for the impacts of fire on savannah ecology. The validated model can then be used to predict the savannah's flux dynamics under the fire scenarios expected with climate and/or human impact change.

  2. Multiscale Trend Analysis for Pampa Grasslands Using Ground Data and Vegetation Sensor Imagery

    Directory of Open Access Journals (Sweden)

    Fernando C. Scottá

    2015-07-01

    Full Text Available This study aimed to evaluate changes in the aboveground net primary productivity (ANPP of grasslands in the Pampa biome by using experimental plots and changes in the spectral responses of similar vegetation communities obtained by remote sensing and to compare both datasets with meteorological variations to validate the transition scales of the datasets. Two different geographic scales were considered in this study. At the local scale, an analysis of the climate and its direct influences on grassland ANPP was performed using data from a long-term experiment. At the regional scale, the influences of climate on the grassland reflectance patterns were determined using vegetation sensor imagery data. Overall, the monthly variations of vegetation canopy growth analysed using environmental changes (air temperature, total rainfall and total evapotranspiration were similar. The results from the ANPP data and the NDVI data showed the that variations in grassland growth were similar and independent of the analysis scale, which indicated that local data and the relationships of local data with climate can be considered at the regional scale in the Pampa biome by using remote sensing.

  3. Estimates of grassland biomass and turnover time on the Tibetan Plateau

    Science.gov (United States)

    Xia, Jiangzhou; Ma, Minna; Liang, Tiangang; Wu, Chaoyang; Yang, Yuanhe; Zhang, Li; Zhang, Yangjian; Yuan, Wenping

    2018-01-01

    The grassland of the Tibetan Plateau forms a globally significant biome, which represents 6% of the world’s grasslands and 44% of China’s grasslands. However, large uncertainties remain concerning the vegetation carbon storage and turnover time in this biome. In this study, we quantified the pool size of both the aboveground and belowground biomass and turnover time of belowground biomass across the Tibetan Plateau by combining systematic measurements taken from a substantial number of surveys (i.e. 1689 sites for aboveground biomass, 174 sites for belowground biomass) with a machine learning technique (i.e. random forest, RF). Our study demonstrated that the RF model is effective tool for upscaling local biomass observations to the regional scale, and for producing continuous biomass estimates of the Tibetan Plateau. On average, the models estimated 46.57 Tg (1 Tg = 1012g) C of aboveground biomass and 363.71 Tg C of belowground biomass in the Tibetan grasslands covering an area of 1.32 × 106 km2. The turnover time of belowground biomass demonstrated large spatial heterogeneity, with a median turnover time of 4.25 years. Our results also demonstrated large differences in the biomass simulations among the major ecosystem models used for the Tibetan Plateau, largely because of inadequate model parameterization and validation. This study provides a spatially continuous measure of vegetation carbon storage and turnover time, and provides useful information for advancing ecosystem models and improving their performance.

  4. Research priorities for grassland science: the need of long term integrated experiments networks

    Directory of Open Access Journals (Sweden)

    G. Lemaire

    2007-07-01

    Full Text Available Grasslands have to be considered not only as a mean for providing foods for domestic herbivore but also as an important biome of terrestrial biosphere. This function of grasslands as an active component of our environment requires specific studies on the role and impact of this ecosystem on soil erosion and soil quality, quality and quantity of water resources, atmosphere composition and greenhouse gas emission or sequestration, biodiversity dynamics at different scales from field plot to landscape. All these functions have to be evaluated in conjunction with the function of providing animal products for increasing human population. So multifunctionality of grasslands become a new paradigm for grassland science. Environmental and biodiversity outputs require long term studies, being the long term retro-active processes within soil, vegetation and micro-organism communities in relation to changes in management programme. So grassland science needs to carry on long term integrated experimentation for studying all the environmental outputs and ecological services associated to grassland management systems.

  5. Increasing temperature reduces the coupling between available nitrogen and phosphorus in soils of Chinese grasslands

    Science.gov (United States)

    Geng, Yan; Baumann, Frank; Song, Chao; Zhang, Mi; Shi, Yue; Kühn, Peter; Scholten, Thomas; He, Jin-Sheng

    2017-03-01

    Changes in climatic conditions along geographical gradients greatly affect soil nutrient cycling processes. Yet how climate regimes such as changes in temperature influence soil nitrogen (N) and phosphorus (P) concentrations and their stoichiometry is not well understood. This study investigated the spatial pattern and variability of soil N and P availability as well as their coupling relationships at two soil layers (0-10 and 10-20 cm) along a 4000-km climate transect in two grassland biomes of China, the Inner Mongolian temperate grasslands and the Tibetan alpine grasslands. Our results found that in both grasslands, from cold to warm sites the amounts of soil total N, total P and available P all decreased. By contrast, the amount of available N was positively related to mean annual temperature in the Tibetan grasslands. Meanwhile, with increasing temperature ratio of available N to P significantly increased but the linear relationship between them was considerably reduced. Thus, increasing temperature may not only induce a stoichiometric shift but also loose the coupling between available N and P. This N-P decoupling under warmer conditions was more evident in the Tibetan alpine grasslands where P limitation might become more widespread relative to N as temperatures continue to rise.

  6. Modified Light Use Efficiency Model for Assessment of Carbon Sequestration in Grasslands of Kazakhstan: Combining Ground Biomass Data and Remote-sensing

    Science.gov (United States)

    Propastin, Pavel A.; Kappas, Martin W.; Herrmann, Stefanie M.; Tucker, Compton J.

    2012-01-01

    A modified light use efficiency (LUE) model was tested in the grasslands of central Kazakhstan in terms of its ability to characterize spatial patterns and interannual dynamics of net primary production (NPP) at a regional scale. In this model, the LUE of the grassland biome (en) was simulated from ground-based NPP measurements, absorbed photosynthetically active radiation (APAR) and meteorological observations using a new empirical approach. Using coarse-resolution satellite data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), monthly NPP was calculated from 1998 to 2008 over a large grassland region in Kazakhstan. The modelling results were verified against scaled up plot-level observations of grassland biomass and another available NPP data set derived from a field study in a similar grassland biome. The results indicated the reliability of productivity estimates produced by the model for regional monitoring of grassland NPP. The method for simulation of en suggested in this study can be used in grassland regions where no carbon flux measurements are accessible.

  7. Tropical rainforest biome of Biosphere 2. Structure, composition and results of the first 2 years of operation

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, Linda S. [Systems Ecology and Energy Analysis Program, Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL (United States); Burgess, Tony; Marino, Bruno D.V.; Wei, Yong Dan [Biosphere 2 Center, Inc. P.O. Box 689, Oracle, AZ (United States)

    1999-06-01

    The tropical rainforest biome in the Biosphere 2 mesocosm was managed with rainfall and temperature conditions to simulate a natural rainforest typical of the new world tropics. The establishment of the biome was based on the introduction of excessive numbers of species allowing self-organization of an ecologically unique rainforest. Over 282 species of plants from rainforest areas were planted within the topographically diverse rainforest biome (area of 1900 m{sup 2}, volume of 35,000 m{sup 3}), just before the Biosphere 2 closure in 1991. Approximately 61% of these species survived when counted in 1993, representing a plant species richness reduction to 172 species in 0.19 hectare. Rank order graphs show that a high diversity community resulted not unlike insular rainforests. The plants of the rainforest mesocosm, however, grew under anomalous conditions of soil (amended desert grassland soil), atmospheric composition (CO{sub 2} up to 4500 ppm by volume (ppmv)) and rainwater composition (high salinity and nutrients). Stem growth rates of a dominant canopy tree, Cecropia, were up to four times higher but had reduced diameter at breast height compared to natural counterparts. Human intervention in plant succession was also an important factor in shaping the ecology of the rainforest biome of Biosphere 2

  8. Modeling impacts of human footprint and soil variability on the potential distribution of invasive plant species in different biomes

    Science.gov (United States)

    Wan, Ji-Zhong; Wang, Chun-Jing; Yu, Fei-Hai

    2017-11-01

    Human footprint and soil variability may be important in shaping the spread of invasive plant species (IPS). However, until now, there is little knowledge on how human footprint and soil variability affect the potential distribution of IPS in different biomes. We used Maxent modeling to project the potential distribution of 29 IPS with wide distributions and long introduction histories in China based on various combinations of climatic correlates, soil characteristics and human footprint. Then, we evaluated the relative importance of each type of environmental variables (climate, soil and human footprint) as well as the difference in range and similarity of the potential distribution of IPS between different biomes. Human footprint and soil variables contributed to the prediction of the potential distribution of IPS, and different types of biomes had varying responses and degrees of impacts from the tested variables. Human footprint and soil variability had the highest tendency to increase the potential distribution of IPS in Montane Grasslands and Shrublands. We propose to integrate the assessment in impacts of human footprint and soil variability on the potential distribution of IPS in different biomes into the prevention and control of plant invasion.

  9. Grassland biodiversity can pay.

    Science.gov (United States)

    Binder, Seth; Isbell, Forest; Polasky, Stephen; Catford, Jane A; Tilman, David

    2018-04-10

    The biodiversity-ecosystem functioning (BEF) literature provides strong evidence of the biophysical basis for the potential profitability of greater diversity but does not address questions of optimal management. BEF studies typically focus on the ecosystem outputs produced by randomly assembled communities that only differ in their biodiversity levels, measured by indices such as species richness. Landholders, however, do not randomly select species to plant; they choose particular species that collectively maximize profits. As such, their interest is not in comparing the average performance of randomly assembled communities at each level of biodiversity but rather comparing the best-performing communities at each diversity level. Assessing the best-performing mixture requires detailed accounting of species' identities and relative abundances. It also requires accounting for the financial cost of individual species' seeds, and the economic value of changes in the quality, quantity, and variability of the species' collective output-something that existing multifunctionality indices fail to do. This study presents an assessment approach that integrates the relevant factors into a single, coherent framework. It uses ecological production functions to inform an economic model consistent with the utility-maximizing decisions of a potentially risk-averse private landowner. We demonstrate the salience and applicability of the framework using data from an experimental grassland to estimate production relationships for hay and carbon storage. For that case, our results suggest that even a risk-neutral, profit-maximizing landowner would favor a highly diverse mix of species, with optimal species richness falling between the low levels currently found in commercial grasslands and the high levels found in natural grasslands.

  10. Ecosystem-scale carbon monoxide exchange and partitioning across major biomes in Europe

    Science.gov (United States)

    Hammerle, Albin; Spielmann, Felix; Kitz, Florian; Ibrom, Andreas; Migliavacca, Mirco; Noe, Steffen; Kolle, Olaf; Moreno, Gerardo; Wohlfahrt, Georg

    2017-04-01

    With an average mole fraction of 100 ppb carbon monoxide (CO) plays a critical role in atmospheric chemistry and has an indirect global warming potential. While sources/sinks of CO on land at least partially cancel out each other and their magnitude is very likely lower compared to other sinks and sources, the magnitude of CO sources and sinks is highly uncertain. Thus it may be premature to neglect any direct contributions of land ecosystems to the CO budget. In addition, changes in global climate and resulting changes in global productivity may require re-evaluating older data and assumptions. One major reason for the large uncertainty is a general scarcity of empirical data. Here we present data on continuous eddy covariance measurements of CO-fluxes above different biomes in Europe in combination with soil-chamber flux measurements. Eddy covariance and soil-chamber measurements were conducted during the vegetation periods in 2015 and 2016 at a temperate grassland (AUT), a Mediterranean savanna (ESP), a temperate mixed deciduous (DEN) and a hemi-boreal forest (EST). While a clear diel pattern in ecosystem-scale CO-fluxes could be observed at the two grassland sites, with comparatively high emission rates at daytime conditions and fluxes around zero at night, no such pattern could be found for the two forest sites. Soil-chamber measurements mimicked the ecosystem-scale fluxes with CO-emissions during the day at the grassland ecosystems and slightly negative fluxes at night. Applying different treatments the influence of radiation and the availability of litter on these fluxes could be shown. Furthermore, a two-month rainout experiment revealed hardly any differences in CO soil fluxes between rainout- and control-plots at the grassland site (AUT), unless extremely dry conditions were reached.

  11. The Eurasian Dry Grassland Group (EDGG in 2016–2017

    Directory of Open Access Journals (Sweden)

    Venn Stephen

    2018-06-01

    Full Text Available This report summarizes the activities and achievements of the Eurasian Dry Grassland Group (EDGG from mid-2016 through to the end of 2017. During this period, the 13th Eurasian Grassland Conference took place in Sighişoara, Romania, and the 14th conference was held in Riga, Latvia. The 10th EDGG Field Workshop on Biodiversity patterns across a precipitation gradient in the Central Apennine mountains was conducted in the Central Apennines, Italy, this time in addition to multi-scale sampling of vascular plants, bryophytes and lichens, also including one animal group (leaf hoppers. Apart from the quarterly issues of its own electronic journal (Bulletin of the Eurasian Dry Grassland Group, EDGG also finalised five grassland-related Special Features/Issues during the past 1.5 years in the following international journals: Applied Vegetation Science, Biodiversity and Conservation, Phytocoenologia, Tuexenia and Hacquetia. Beyond that, EDGG facilitated various national and supra-national vegetationplot databases of grasslands and established its own specialised database for standardised multi-scale plot data of Palaearctic grasslands (GrassPlot.

  12. Carbon balance of renovated grasslands: input- or output-driven?

    Science.gov (United States)

    Choncubhair, Órlaith Ní; Osborne, Bruce; Lanigan, Gary

    2015-04-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. In permanent temperate grasslands, biomass production and sward quality can deteriorate over time and periodic renovation activities, involving soil tillage and reseeding, are commonly carried out to halt this decline. Long-term cultivation of agricultural land has been associated with soil aggregate degradation and reduced soil carbon storage. However, the impact of these single tillage disturbances on C cycling in grasslands is less clear. This study evaluated gaseous and dissolved organic carbon (DOC) losses following a single tillage event by subjecting grassland lysimeters with contrasting soil drainage characteristics to simulated conventional inversion or minimum tillage. Field-scale CO2 emissions after conventional tillage were also quantified and empirically modelled over short- and medium-term timeframes to delineate the ecosystem response to environmental variables. Soil moisture was the limiting determinant of ecosystem carbon release following conventional tillage. Freshly-tilled soils were associated with reduced water retention and increased sensitivity to soil moisture, which was particularly pronounced following rewetting events. Significantly elevated but ephemeral CO2 effluxes were detected in the hours following inversion ploughing, however tillage disturbance did not generate significantly enhanced C emission rates in the medium term. Equally, DOC losses were not significantly amplified by conventional tillage compared with conservative minimum tillage and were predominantly controlled by soil drainage across tillage regimes. Our results suggest that a net ecosystem source of 120 to 210 g C m-2 over an approximately two-month period was most likely a consequence of reduced productivity and C input rather than enhanced soil CO2

  13. On coupling global biome models with climate models

    International Nuclear Information System (INIS)

    Claussen, M.

    1994-01-01

    The BIOME model of Prentice et al. (1992), which predicts global vegetation patterns in equilibrium with climate, is coupled with the ECHAM climate model of the Max-Planck-Institut fuer Meteorologie, Hamburg. It is found that incorporation of the BIOME model into ECHAM, regardless at which frequency, does not enhance the simulated climate variability, expressed in terms of differences between global vegetation patterns. Strongest changes are seen only between the initial biome distribution and the biome distribution computed after the first simulation period, provided that the climate-biome model is started from a biome distribution that resembles the present-day distribution. After the first simulation period, there is no significant shrinking, expanding, or shifting of biomes. Likewise, no trend is seen in global averages of land-surface parameters and climate variables. (orig.)

  14. Woody plant encroachment of grasslands: a comparison of terrestrial and wetland settings.

    Science.gov (United States)

    Saintilan, Neil; Rogers, Kerrylee

    2015-02-01

    A global trend of woody plant encroachment of terrestrial grasslands is co-incident with woody plant encroachment of wetland in freshwater and saline intertidal settings. There are several arguments for considering tree encroachment of wetlands in the context of woody shrub encroachment of grassland biomes. In both cases, delimitation of woody shrubs at regional scales is set by temperature thresholds for poleward extent, and by aridity within temperature limits. Latitudinal expansion has been observed for terrestrial woody shrubs and mangroves, following recent warming, but most expansion and thickening has been due to the occupation of previously water-limited grassland/saltmarsh environments. Increases in atmospheric CO₂, may facilitate the recruitment of trees in terrestrial and wetland settings. Improved water relations, a mechanism that would predict higher soil moisture in grasslands and saltmarshes, and also an enhanced capacity to survive arid conditions, reinforces local mechanisms of change. The expansion of woody shrubs and mangroves provides a negative feedback on elevated atmospheric CO₂ by increasing carbon sequestration in grassland and saltmarsh, and is a significant carbon sink globally. These broad-scale vegetation shifts may represent a new stable state, reinforced by positive feedbacks between global change drivers and endogenic mechanisms of persistence in the landscape.

  15. Interpreting forest and grassland biome productivity utilizing nested scales of image resolution and biogeographical analysis

    Science.gov (United States)

    Iverson, Louis R.; Cook, Elizabeth A.; Graham, Robin L.; Olson, Jerry S.; Frank, Thomas; Ke, Ying; Treworgy, Colin; Risser, Paul G.

    1987-01-01

    This report summarizes progress made in our investigation of forest productivity assessment using TM and other biogeographical data during the third six-month period of the grant. Data acquisition and methodology hurdles are largely complete. Four study areas for which the appropriate TM and ancillary data were available are currently being intensively analyzed. Significant relationships have been found on a site by site basis to suggest that forest productivity can be qualitatively assessed using TM band values and site characteristics. Perhaps the most promising results relate TM unsupervised classes to forest productivity, with enhancement from elevation data. During the final phases of the research, multi-temporal and regional comparisons of results will be addressed, as well as the predictability of forest productivity patterns over a large region using TM data and/or TM nested within AVHRR data.

  16. Biome Is Where the Art Is

    Science.gov (United States)

    Gooden, Kelly

    2005-01-01

    The author is surprised every year when fifth-grade students react to the study of biomes as if they've never given any thought to the differences across parts of the world. Sure, they've all heard of the tropical rain forest and the desert, but it seems as though they think the rest of the world is just some undefined area with climate, animals,…

  17. Cross-biome metagenomic analyses of soil microbial communities and their functional attributes.

    Science.gov (United States)

    Fierer, Noah; Leff, Jonathan W; Adams, Byron J; Nielsen, Uffe N; Bates, Scott Thomas; Lauber, Christian L; Owens, Sarah; Gilbert, Jack A; Wall, Diana H; Caporaso, J Gregory

    2012-12-26

    For centuries ecologists have studied how the diversity and functional traits of plant and animal communities vary across biomes. In contrast, we have only just begun exploring similar questions for soil microbial communities despite soil microbes being the dominant engines of biogeochemical cycles and a major pool of living biomass in terrestrial ecosystems. We used metagenomic sequencing to compare the composition and functional attributes of 16 soil microbial communities collected from cold deserts, hot deserts, forests, grasslands, and tundra. Those communities found in plant-free cold desert soils typically had the lowest levels of functional diversity (diversity of protein-coding gene categories) and the lowest levels of phylogenetic and taxonomic diversity. Across all soils, functional beta diversity was strongly correlated with taxonomic and phylogenetic beta diversity; the desert microbial communities were clearly distinct from the nondesert communities regardless of the metric used. The desert communities had higher relative abundances of genes associated with osmoregulation and dormancy, but lower relative abundances of genes associated with nutrient cycling and the catabolism of plant-derived organic compounds. Antibiotic resistance genes were consistently threefold less abundant in the desert soils than in the nondesert soils, suggesting that abiotic conditions, not competitive interactions, are more important in shaping the desert microbial communities. As the most comprehensive survey of soil taxonomic, phylogenetic, and functional diversity to date, this study demonstrates that metagenomic approaches can be used to build a predictive understanding of how microbial diversity and function vary across terrestrial biomes.

  18. Anthropogenic Biomes of the World, Version 2: 1700

    Data.gov (United States)

    National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1700 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

  19. Anthropogenic Biomes of the World, Version 2: 1900

    Data.gov (United States)

    National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1900 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

  20. Anthropogenic Biomes of the World, Version 2: 1800

    Data.gov (United States)

    National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1800 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

  1. Anthropogenic Biomes of the World, Version 2: 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 2000 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

  2. La filatelia biomédica

    OpenAIRE

    Emilio J.A. Roldán; Claudio Zuckerberg

    2011-01-01

    La temática biomédica es un capítulo extendido de la filatelia o coleccionismo de sellos postales. Inaugura la temática la imagen de la diosa Hygeia, en un sello de la isla Nevis de 1861. Los primeros médicos retratados en una estampilla son tres constitucionalistas americanos, en un ejemplar de 1869, pero recién en 1937 aparecen médicos holandeses en reconocimiento específico de sus aportes a la salud. En la Argentina la primera estampilla que oficialmente se ocupa del tema es de 1944, en ay...

  3. La filatelia biomédica

    Directory of Open Access Journals (Sweden)

    Emilio J.A. Roldán

    2011-02-01

    Full Text Available La temática biomédica es un capítulo extendido de la filatelia o coleccionismo de sellos postales. Inaugura la temática la imagen de la diosa Hygeia, en un sello de la isla Nevis de 1861. Los primeros médicos retratados en una estampilla son tres constitucionalistas americanos, en un ejemplar de 1869, pero recién en 1937 aparecen médicos holandeses en reconocimiento específico de sus aportes a la salud. En la Argentina la primera estampilla que oficialmente se ocupa del tema es de 1944, en ayuda de las víctimas del terremoto de San Juan. Florentino Ameghino es el primer científico incluido en 1954, y en 1967 se edita un sello conmemorativo de la Dra. Cecilia Grierson. La filatelia argentina luego reconoce varios de nuestros científicos y médicos, congresos, universidades, campañas sanitarias, temas de odontología, farmacia, enfermería y otros, generando un amplio material filatélico en reconocimiento del valor social que la ciencia biomédica argentina ha logrado en el contexto propio e internacional. Posiblemente sea un científico, el Dr. Bernardo Houssay, uno de los argentinos más veces editado en distintos sellos postales de la filatelia mundial.

  4. An assessment of rehabilitation success in an African grassland using ants as bioindicators

    Directory of Open Access Journals (Sweden)

    Samantha-Leigh Jamison

    2016-09-01

    Full Text Available Many studies that evaluate rehabilitation make use of invertebrate bioindicators. Invertebrates, especially ants, make useful indicators as they are sensitive to environmental change. We compared ant assemblages in rehabilitated and control sites in the Rietvlei Nature Reserve, a protected area important for grassland conservation in South Africa. Pitfall traps were used to sample ant assemblages at six control sites and six rehabilitated sites. In addition, environmental and vegetation surveys were conducted at each site. We found that the ant assemblages differed significantly between the control and rehabilitated sites, although there was considerable overlap; the control sites supported a greater species density and higher abundance of ants than the rehabilitated sites. In total, 36 ant species were collected (control sites: 34 species; rehabilitated sites: 26 species. The environmental survey revealed that percentages of bare ground and coarse sand, as well as soil pH, differed significantly between the control and rehabilitated sites. The control and rehabilitated sites also supported significantly different plant assemblages. Three indicator ant species were identified for the control sites: Crematogaster rectinota, Crematogaster amita and Monomorium fastidium. No indicator species were identified for the rehabilitated sites. These results suggest that recovery from the previous agricultural use of the area is still incomplete and highlights the lack of research examining the success of rehabilitation in the grassland biome. Conservation implications: The present study illustrates the need for further research on rehabilitation techniques utilised in the grassland biome. This is of value as the remainder of South African grasslands are considered critically endangered.

  5. Protecting Mongolia's grassland steppes | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... windy grassland region is severely damaged, desertification can quickly set in. ... to marketing to the sound use of (grassland) resources," explains Ykhanbai, who ... is going to require improvement in the skills of researchers, adds Ykhanbai.

  6. Climate-biomes, pedo-biomes and pyro-biomes: which world view explains the tropical forest - savanna boundary in South America?

    Science.gov (United States)

    Langan, Liam; Higgins, Steven; Scheiter, Simon

    2015-04-01

    Elucidating the drivers of broad vegetation formations improves our understanding of earth system functioning. The biome, defined primarily by the dominance of a particular growth strategy, is commonly employed to group vegetation into similar units. Predicting tropical forest and savanna biome boundaries in South America has proven difficult. Process based DGVMs (Dynamic global vegetation models) are our best tool to simulate vegetation patterns, make predictions for future changes and test theory, however, many DGVMs fail to accurately simulate the spatial distribution or indeed presence of the South American savanna biome which can result in large differences in modelled ecosystem structural properties. Evidence suggests fire plays a significant role in mediating these forest and savanna biome boundaries, however, fire alone does not appear to be sufficient to predict these boundaries in South America using DGVMs hinting at the presence of one or more missing environmental factors. We hypothesise that soil depth, which affects plant available water by determining maximum storage potential and influences temporal availability, may be one of these missing environmental factors. To test our hypothesis we use a novel vegetation model, the aDGVM2. This model has been specifically designed to allow plant trait strategies, constrained by trade-offs between traits, evolve based on the abiotic and biotic conditions where the resulting community trait suites are emergent properties of model dynamics. Furthermore it considers root biomass in multiple soil layers and therefore allows the consideration of alternative rooting strategies, which in turn allows us to explore in more detail the role of soil hydraulic factors in controlling biome boundary distributions. We find that changes in soil depth, interacting with fire, affect the relative dominance of tree and grass strategies and thus the presence and spatial distribution of forest and savanna biomes in South America

  7. Appreciation of grassland functions by European stakeholders

    NARCIS (Netherlands)

    Pol, van den A.; Golinski, P.; Hennessy, D.; Huyghe, C.; Parente, G.; Peyraud, J.L.

    2014-01-01

    In order to promote sustainable and competitive ruminant production systems, the European Multisward project was aimed at improving farmer trust in grassland and grassland mixtures. A questionnaire on grassland functions was submitted in eight languages, in order to better understand the importance

  8. Montane plant environments in the Fynbos Biome

    Directory of Open Access Journals (Sweden)

    B. M. Campbell

    1983-12-01

    Full Text Available Environmental data collected at 507 plots on 22 transects, and soil analytical data from 81 of these plots, have been used to describe the plant environments of the mountains in the Fynbos Biome. Two major regional gradients are recognized: a west-east gradient and a coast-interior gradient. Of particular consequence for fynbos-environment studies is the increase in the proportion of fine soil particles from west to east. At least some aspects of soil fertility also increase towards the east. The edaphic changes are paralleled by climatic changes: chiefly a decrease in the severity of summer drought towards the east. On the coast-interior gradient a major non-climatic variable in the gradient is rock cover. High rock cover is a feature of the interior ranges. Soils with organic horizons or with E horizons are a feature on the coastal mountains, but are generally lacking on the interior mountains. The other environmental gradients recognized occur on individual transects and all include edaphic variables. The rockiness-soil depth gradient, on which an increase in rockiness is associated with a decrease in soil depth and usually a decrease in clay content, tends to occur in three situations. Firstly, it is associated with local topographic variation; the shallow, rocky soils being a feature of the steeper slopes. Secondly, it is associated with the aspect gradient; the hot, dry northern aspects having shallow, rocky, less developed soils. Thirdly, it tends to be associated with the altitude-rainfall gradient: shallower soils being found at higher altitudes. It is also at higher altitudes that higher rainfall is found. Variation in oxidizable carbon is chiefly accounted for by the altitude-rainfall gradient. Whereas at a biome-wide level, aspects of soil fertility are related to soil texture, it appears that on individual transects fertility is linked to amounts of plant remains in the soil and to rainfall. Apart from these gradients, which are

  9. Research on the Mechanism of Cross Regional Grassland Ecological Compensation

    Science.gov (United States)

    Yang, Ran; Ma, Jun

    2018-01-01

    In recent years, grassland environmental damage has become serious, and grassland resources protection task has become heavy, grassland ecological compensation has become an effective way to solve this problem; but the current grassland ecological compensation standards were low, the effect is poor. The fundamental reason is the model of administrative division destroys the integrity of grassland. Based on the analysis of the status quo of grassland compensation, this paper tries to protect the grassland integrity, breaks the administrative division restriction, implements the space regulation, constructs the framework of cross-regional grassland ecological compensation mechanism, describes its operation process. It provides new way to realize the sustainable development of the grassland environment.

  10. Using an Exploratory Internet Activity & Trivia Game to Teach Students about Biomes

    Science.gov (United States)

    Richardson, Matthew L.

    2009-01-01

    Students in life science classes need an introduction to biomes, including an introduction to the concept, key biotic and abiotic features of biomes, and geographic locations of biomes. In this activity, students in seventh- and eighth-grade science classes used a directed exploratory Internet activity to learn about biomes. The author tested…

  11. Structural characterization of vegetation in the fynbos biome

    CSIR Research Space (South Africa)

    Campbell, BM

    1981-08-01

    Full Text Available A proposed system for the standardization of descriptive terminology for structural characterization of vegetation in the Fynbos Biome is presented in tabular form. Specific applications of the system are described and illustrations of some...

  12. Forest resilience to drought varies across biomes.

    Science.gov (United States)

    Gazol, Antonio; Camarero, Jesus Julio; Vicente-Serrano, Sergio M; Sánchez-Salguero, Raúl; Gutiérrez, Emilia; de Luis, Martin; Sangüesa-Barreda, Gabriel; Novak, Klemen; Rozas, Vicente; Tíscar, Pedro A; Linares, Juan C; Martín-Hernández, Natalia; Martínez Del Castillo, Edurne; Ribas, Montse; García-González, Ignacio; Silla, Fernando; Camisón, Alvaro; Génova, Mar; Olano, José M; Longares, Luis A; Hevia, Andrea; Tomás-Burguera, Miquel; Galván, J Diego

    2018-05-01

    Forecasted increase drought frequency and severity may drive worldwide declines in forest productivity. Species-level responses to a drier world are likely to be influenced by their functional traits. Here, we analyse forest resilience to drought using an extensive network of tree-ring width data and satellite imagery. We compiled proxies of forest growth and productivity (TRWi, absolutely dated ring-width indices; NDVI, Normalized Difference Vegetation Index) for 11 tree species and 502 forests in Spain corresponding to Mediterranean, temperate, and continental biomes. Four different components of forest resilience to drought were calculated based on TRWi and NDVI data before, during, and after four major droughts (1986, 1994-1995, 1999, and 2005), and pointed out that TRWi data were more sensitive metrics of forest resilience to drought than NDVI data. Resilience was related to both drought severity and forest composition. Evergreen gymnosperms dominating semi-arid Mediterranean forests showed the lowest resistance to drought, but higher recovery than deciduous angiosperms dominating humid temperate forests. Moreover, semi-arid gymnosperm forests presented a negative temporal trend in the resistance to drought, but this pattern was absent in continental and temperate forests. Although gymnosperms in dry Mediterranean forests showed a faster recovery after drought, their recovery potential could be constrained if droughts become more frequent. Conversely, angiosperms and gymnosperms inhabiting temperate and continental sites might have problems to recover after more intense droughts since they resist drought but are less able to recover afterwards. © 2018 John Wiley & Sons Ltd.

  13. Net Biome Productivity of different land use at the sites of the Tharandt cluster

    Science.gov (United States)

    Grünwald, T.; Prescher, A.-K.; Bernhofer, Ch.

    2009-04-01

    Within the Tharandt cluster there are 5 flux monitoring sites including 3 CARBOEUROPE main sites. The CARBOEUROPE sites cover typical land use of the region (spruce [monitored since 1996], grassland [since 2003], cropland [since 2004]). For all sites estimates of the Net Biome Productivity (NBP) and its uncertainty have been derived using Net Ecosystem Productivity (NEP) based on the EC measurements and C exports and imports on an annual basis. The crop site is a small C sink (NEP of 30-110gCm-2a-1) only. The annual NEP values are dependent on the cultivated crop species (winter or summer crop). Including C export (harvest) and C import (manure spreading) lead to a considerable C source of 270-540gCm-2a-1. Organic fertilisation (C import) has a strong impact on NBP values expressed in a reduced annual net carbon source. Also, the largest interannual differences of NBP values are found at this site - mainly induced by the existence and the amount of a carbon import due to organic fertilisation. Management practices affect the NBP in a sensitive way at this crop site. Each crop shows a higher C export due to harvest than the annual NEP. To validate the calculated C equivalent using harvested grain biomass modelled NPP values are available. Uncertainty ranges of C export, C import and NBP as well as the grassland and spruce NBP (for comparison) are also stated. In general, land use and management strongly affect the annual NBP of non-forested ecosystems especially. So, this is the second main driver of the C budget besides the interannual variability in meteorological conditions and water availability with its influence on NEP, GPP and TER.

  14. Assessing MODIS GPP in Non-Forested Biomes in Water Limited Areas Using EC Tower Data

    Directory of Open Access Journals (Sweden)

    Flor Álvarez-Taboada

    2015-03-01

    Full Text Available Although shrublands, savannas and grasslands account for 37% of the world’s terrestrial area, not many studies have analysed the role of these ecosystems in the global carbon cycle at a regional scale. The MODIS Gross Primary Production (GPP product is used here to help bridge this gap. In this study, the agreement between the MODIS GPP product (GPPm and the GPP Eddy Covariance tower data (GPPec was tested for six different sites in temperate and dry climatic regions (three grasslands, two shrublands and one evergreen forest. Results of this study show that for the non-forest sites in water-limited areas, GPPm is well correlated with GPPec at annual scales (r2 = 0.77, n = 12; SEE = 149.26 g C∙m−2∙year−1, although it tends to overestimate GPP and it is less accurate in the sites with permanent water restrictions. The use of biome-specific models based on precipitation measurements at a finer spatial resolution than the Data Assimilation Office (DAO values can increase the accuracy of these estimations. The seasonal dynamics and the beginning and end of the growing season were well captured by GPPm for the sites where (i the productivity was low throughout the year or (ii the changes in the flux trend were abrupt, usually due to the restrictions in water availability. The agreement between GPPec and GPPm in non-forested sites was lower on a weekly basis than at an annual scale (0.44 ≤ r2 ≤ 0.49, but these results were improved by including meteorological data at a finer spatial scale, and soil water content and temperature measurements in the model developed to predict GPPec (0.52 ≤ r2 ≤ 0.65.

  15. On coupling global biome models with climate models

    OpenAIRE

    Claussen, M.

    1994-01-01

    The BIOME model of Prentice et al. (1992; J. Biogeogr. 19: 117-134), which predicts global vegetation patterns in equilibrium with climate, was coupled with the ECHAM climate model of the Max-Planck-Institut fiir Meteorologie, Hamburg, Germany. It was found that incorporation of the BIOME model into ECHAM, regardless at which frequency, does not enhance the simulated climate variability, expressed in terms of differences between global vegetation patterns. Strongest changes are seen only betw...

  16. Diverging responses of tropical Andean biomes under future climate conditions.

    Directory of Open Access Journals (Sweden)

    Carolina Tovar

    Full Text Available Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%-17.4%, there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar

  17. Generality of leaf trait relationships: A test across six biomes

    Energy Technology Data Exchange (ETDEWEB)

    Reich, P.B. [Univ. of Minnesota, Saint Paul, MN (United States). Dept. of Forest Resources; Ellsworth, D.S. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science; Walters, M.B. [Michigan State Univ., East Lansing, MI (United States). Dept. of Forestry; Vose, J.M. [Forest Service, Otto, NC (United States). Coweeta Hydrological Lab.; Gresham, C. [Clemson Univ., Georgetown, SC (United States). Baruch Forest Inst.; Volin, J.C. [Florida Atlantic Univ., Davie, FL (United States). Div. of Science; Bowman, W.D. [Inst. of Arctic and Alpine Research, Boulder, CO (United States). Mountain Research Station]|[Univ. of Colorado, Boulder, CO (United States). Dept. of Evolutionary, Population, and Organismic Biology

    1999-09-01

    Convergence in interspecific leaf trait relationships across diverse taxonomic groups and biomes would have important evolutionary and ecological implications. Such convergence has been hypothesized to result from trade-offs that limit the combination of plant traits for any species. Here the authors address this issue by testing for biome differences in the slope and intercept of interspecific relationships among leaf traits: longevity, net photosynthetic capacity (A{sub max}), leaf diffusive conductance (G{sub S}), specific leaf area (SLA), and nitrogen (N) status, for more than 100 species in six distinct biomes of the Americas. The six biomes were: alpine tundra-subalpine forest ecotone, cold temperate forest-prairie ecotone, montane cool temperate forest, desert shrubland, subtropical forest, and tropical rain forest. Despite large differences in climate and evolutionary history, in all biomes mass-based leaf N (N{sub mass}), SLA, G{sub S}, and A{sub max} were positively related to one another and decreased with increasing leaf life span. The relationships between pairs of leaf traits exhibited similar slopes among biomes, suggesting a predictable set of scaling relationships among key leaf morphological, chemical, and metabolic traits that are replicated globally among terrestrial ecosystems regardless of biome or vegetation type. However, the intercept (i.e., the overall elevation of regression lines) of relationships between pairs of leaf traits usually differed among biomes. With increasing aridity across sites, species had greater A{sub max} for a given level of G{sub S} and lower SLA for any given leaf life span. Using principal components analysis, most variation among species was explained by an axis related to mass-based leaf traits (A{sub max}, N, and SLA) while a second axis reflected climate, G{sub S}, and other area-based leaf traits.

  18. Combining Livestock Production Information in a Process-Based Vegetation Model to Reconstruct the History of Grassland Management

    Science.gov (United States)

    Chang, Jinfeng; Ciais, Philippe; Herrero, Mario; Havlik, Petr; Campioli, Matteo; Zhang, Xianzhou; Bai, Yongfei; Viovy, Nicolas; Joiner, Joanna; Wang, Xuhui; hide

    2016-01-01

    Grassland management type (grazed or mown) and intensity (intensive or extensive) play a crucial role in the greenhouse gas balance and surface energy budget of this biome, both at field scale and at large spatial scale. However, global gridded historical information on grassland management intensity is not available. Combining modelled grass-biomass productivity with statistics of the grass-biomass demand by livestock, we reconstruct gridded maps of grassland management intensity from 1901 to 2012. These maps include the minimum area of managed vs. maximum area of unmanaged grasslands and the fraction of mown vs. grazed area at a resolution of 0.5deg by 0.5deg. The grass-biomass demand is derived from a livestock dataset for 2000, extended to cover the period 19012012. The grass-biomass supply (i.e. forage grass from mown grassland and biomass grazed) is simulated by the process-based model ORCHIDEE-GM driven by historical climate change, risingCO2 concentration, and changes in nitrogen fertilization. The global area of managed grassland obtained in this study increases from 6.1 x 10(exp 6) km(exp 2) in 1901 to 12.3 x 10(exp 6) kmI(exp 2) in 2000, although the expansion pathway varies between different regions. ORCHIDEE-GM also simulated augmentation in global mean productivity and herbage-use efficiency over managed grassland during the 20th century, indicating a general intensification of grassland management at global scale but with regional differences. The gridded grassland management intensity maps are model dependent because they depend on modelled productivity. Thus specific attention was given to the evaluation of modelled productivity against a series of observations from site-level net primary productivity (NPP) measurements to two global satellite products of gross primary productivity (GPP) (MODIS-GPP and SIF data). Generally, ORCHIDEE-GM captures the spatial pattern, seasonal cycle, and inter-annual variability of grassland productivity at global

  19. Land-use change and soil type are drivers of fungal and archaeal communities in the Pampa biome.

    Science.gov (United States)

    Lupatini, Manoeli; Jacques, Rodrigo Josemar Seminoti; Antoniolli, Zaida Inês; Suleiman, Afnan Khalil Ahmad; Fulthorpe, Roberta R; Roesch, Luiz Fernando Würdig

    2013-02-01

    The current study aimed to test the hypothesis that both land-use change and soil type are responsible for the major changes in the fungal and archaeal community structure and functioning of the soil microbial community in Brazilian Pampa biome. Soil samples were collected at sites with different land-uses (native grassland, native forest, Eucalyptus and Acacia plantation, soybean and watermelon field) and in a typical toposequence in Pampa biome formed by Paleudult, Albaqualf and alluvial soils. The structure of soil microbial community (archaeal and fungal) was evaluated by ribosomal intergenic spacer analysis and soil functional capabilities were measured by microbial biomass carbon and metabolic quotient. We detected different patterns in microbial community driven by land-use change and soil type, showing that both factors are significant drivers of fungal and archaeal community structure and biomass and microbial activity. Fungal community structure was more affected by land-use and archaeal community was more affected by soil type. Irrespective of the land-use or soil type, a large percentage of operational taxonomic unit were shared among the soils. We accepted the hypothesis that both land-use change and soil type are drivers of archaeal and fungal community structure and soil functional capabilities. Moreover, we also suggest the existence of a soil microbial core.

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

    Science.gov (United States)

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

    2014-05-01

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

  1. Invasion of a Legume Ecosystem Engineer in a Cold Biome Alters Plant Biodiversity

    Directory of Open Access Journals (Sweden)

    Vanessa M. S. Vetter

    2018-06-01

    Full Text Available Plant ecosystem engineers are widely used to combat land degradation. However, the ability of those plants to modulate limiting abiotic and biotic resources of other species can cause damage to ecosystems in which they become invasive. Here, we use Lupinus nootkatensis as example to estimate and project the hazardous potential of nitrogen fixing herbaceous plants in a sub-polar oceanic climate. L. nootkatensis was introduced to Iceland in the 1940s to address erosion problems and foster reforestation, but subsequently became a high-latitude invader. In a local field survey, we quantified the impact of L. nootkatensis invasion at three different cover levels (0, 10–50, and 51–100% upon native plant diversity, richness, and community composition of heath-, wood-, and grasslands using a pairwise comparison design and comparisons of means. Afterward, we scaled impacts up to the ecosystem and landscape level by relating occurrences of L. nootkatensis to environmental and human-mediated variables across Iceland using a species distribution model. Plant diversity was significantly deteriorated under high lupine cover levels of the heath- and woodland, but not in the grassland. Plant species richness of the most diverse habitat, the heathland, linearly decreased with lupine cover level. The abundance of small rosettes, cushion plants, orchids, and small woody long-lived plants of the heath declined with invader presence, while the abundance of late successional species and widespread nitrophilous ruderals in wood- and grasslands increased. Distribution modeling revealed 13.3% of Iceland’s land surface area to be suitable lupine habitat. Until 2061–2080, this area will more than double and expand significantly into the Central Highlands due to human mediation and increasingly favorable climatic conditions. Species-rich habitats showed a loss of plant species diversity and richness as well as a change in community composition even in low lupine

  2. Predicting the responsiveness of soil biodiversity to deforestation: a cross-biome study.

    Science.gov (United States)

    Crowther, Thomas W; Maynard, Daniel S; Leff, Jonathan W; Oldfield, Emily E; McCulley, Rebecca L; Fierer, Noah; Bradford, Mark A

    2014-09-01

    The consequences of deforestation for aboveground biodiversity have been a scientific and political concern for decades. In contrast, despite being a dominant component of biodiversity that is essential to the functioning of ecosystems, the responses of belowground biodiversity to forest removal have received less attention. Single-site studies suggest that soil microbes can be highly responsive to forest removal, but responses are highly variable, with negligible effects in some regions. Using high throughput sequencing, we characterize the effects of deforestation on microbial communities across multiple biomes and explore what determines the vulnerability of microbial communities to this vegetative change. We reveal consistent directional trends in the microbial community response, yet the magnitude of this vegetation effect varied between sites, and was explained strongly by soil texture. In sandy sites, the difference in vegetation type caused shifts in a suite of edaphic characteristics, driving substantial differences in microbial community composition. In contrast, fine-textured soil buffered microbes against these effects and there were minimal differences between communities in forest and grassland soil. These microbial community changes were associated with distinct changes in the microbial catabolic profile, placing community changes in an ecosystem functioning context. The universal nature of these patterns allows us to predict where deforestation will have the strongest effects on soil biodiversity, and how these effects could be mitigated. © 2014 John Wiley & Sons Ltd.

  3. Soil respiration at mean annual temperature predicts annual total across vegetation types and biomes

    Directory of Open Access Journals (Sweden)

    M. Bahn

    2010-07-01

    Full Text Available Soil respiration (SR constitutes the largest flux of CO2 from terrestrial ecosystems to the atmosphere. However, there still exist considerable uncertainties as to its actual magnitude, as well as its spatial and interannual variability. Based on a reanalysis and synthesis of 80 site-years for 57 forests, plantations, savannas, shrublands and grasslands from boreal to tropical climates we present evidence that total annual SR is closely related to SR at mean annual soil temperature (SRMAT, irrespective of the type of ecosystem and biome. This is theoretically expected for non water-limited ecosystems within most of the globally occurring range of annual temperature variability and sensitivity (Q10. We further show that for seasonally dry sites where annual precipitation (P is lower than potential evapotranspiration (PET, annual SR can be predicted from wet season SRMAT corrected for a factor related to P/PET. Our finding indicates that it can be sufficient to measure SRMAT for obtaining a well constrained estimate of its annual total. This should substantially increase our capacity for assessing the spatial distribution of soil CO2 emissions across ecosystems, landscapes and regions, and thereby contribute to improving the spatial resolution of a major component of the global carbon cycle.

  4. Effects of Government Grassland Conservation Policy on Household Livelihoods and Dependence on Local Grasslands: Evidence from Inner Mongolia, China

    NARCIS (Netherlands)

    Du, Bingzhen; Zhen, Lin; Yan, Huimin; Groot, de Dolf

    2016-01-01

    Grassland degradation intensifies human-environment conflicts and adversely affects local residents’ livelihoods. To reduce grassland degradation in Inner Mongolia, China, the government has enforced (since 1998) a series of grassland conservation and management policies that restrict the use of

  5. The effects of warming and nitrogen addition on soil nitrogen cycling in a temperate grassland, northeastern China.

    Directory of Open Access Journals (Sweden)

    Lin-Na Ma

    Full Text Available Both climate warming and atmospheric nitrogen (N deposition are predicted to affect soil N cycling in terrestrial biomes over the next century. However, the interactive effects of warming and N deposition on soil N mineralization in temperate grasslands are poorly understood.A field manipulation experiment was conducted to examine the effects of warming and N addition on soil N cycling in a temperate grassland of northeastern China from 2007 to 2009. Soil samples were incubated at a constant temperature and moisture, from samples collected in the field. The results showed that both warming and N addition significantly stimulated soil net N mineralization rate and net nitrification rate. Combined warming and N addition caused an interactive effect on N mineralization, which could be explained by the relative shift of soil microbial community structure because of fungal biomass increase and strong plant uptake of added N due to warming. Irrespective of strong intra- and inter-annual variations in soil N mineralization, the responses of N mineralization to warming and N addition did not change during the three growing seasons, suggesting independence of warming and N responses of N mineralization from precipitation variations in the temperate grassland.Interactions between climate warming and N deposition on soil N cycling were significant. These findings will improve our understanding on the response of soil N cycling to the simultaneous climate change drivers in temperate grassland ecosystem.

  6. Estimating carbon flux phenology with satellite-derived land surface phenology and climate drivers for different biomes: a synthesis of AmeriFlux observations.

    Directory of Open Access Journals (Sweden)

    Wenquan Zhu

    Full Text Available Carbon Flux Phenology (CFP can affect the interannual variation in Net Ecosystem Exchange (NEE of carbon between terrestrial ecosystems and the atmosphere. In this study, we proposed a methodology to estimate CFP metrics with satellite-derived Land Surface Phenology (LSP metrics and climate drivers for 4 biomes (i.e., deciduous broadleaf forest, evergreen needleleaf forest, grasslands and croplands, using 159 site-years of NEE and climate data from 32 AmeriFlux sites and MODIS vegetation index time-series data. LSP metrics combined with optimal climate drivers can explain the variability in Start of Carbon Uptake (SCU by more than 70% and End of Carbon Uptake (ECU by more than 60%. The Root Mean Square Error (RMSE of the estimations was within 8.5 days for both SCU and ECU. The estimation performance for this methodology was primarily dependent on the optimal combination of the LSP retrieval methods, the explanatory climate drivers, the biome types, and the specific CFP metric. This methodology has a potential for allowing extrapolation of CFP metrics for biomes with a distinct and detectable seasonal cycle over large areas, based on synoptic multi-temporal optical satellite data and climate data.

  7. Modelling insights on the partition of evapotranspiration components across biomes

    Science.gov (United States)

    Fatichi, Simone; Pappas, Christoforos

    2017-04-01

    Recent studies using various methodologies have found a large variability (from 35 to 90%) in the ratio of transpiration to total evapotranspiration (denoted as T:ET) across biomes or even at the global scale. Concurrently, previous results suggest that T:ET is independent of mean precipitation and has a positive correlation with Leaf Area Index (LAI). We used the mechanistic ecohydrological model, T&C, with a refined process-based description of soil resistance and a detailed treatment of canopy biophysics and ecophysiology, to investigate T:ET across multiple biomes. Contrary to observation-based estimates, simulation results highlight a well-constrained range of mean T:ET across biomes that is also robust to perturbations of the most sensitive parameters. Simulated T:ET was confirmed to be independent of average precipitation, while it was found to be uncorrelated with LAI across biomes. Higher values of LAI increase evaporation from interception but suppress ground evaporation with the two effects largely cancelling each other in many sites. These results offer mechanistic, model-based, evidence to the ongoing research about the range of T:ET and the factors affecting its magnitude across biomes.

  8. Changes in productivity of grassland with ageing

    NARCIS (Netherlands)

    Hoogerkamp, M.

    1984-01-01

    The productivity of grassland may change greatly with ageing. Frequently, a productive ley period, occurring in the first time after (re)seeding, is followed by a period in which productivity decreases. Under conditions favourable to grassland this may be temporary. A production level

  9. A new framework for evaluating the impacts of drought on net primary productivity of grassland.

    Science.gov (United States)

    Lei, Tianjie; Wu, Jianjun; Li, Xiaohan; Geng, Guangpo; Shao, Changliang; Zhou, Hongkui; Wang, Qianfeng; Liu, Leizhen

    2015-12-01

    This paper presented a valuable framework for evaluating the impacts of droughts (single factor) on grassland ecosystems. This framework was defined as the quantitative magnitude of drought impact that unacceptable short-term and long-term effects on ecosystems may experience relative to the reference standard. Long-term effects on ecosystems may occur relative to the reference standard. Net primary productivity (NPP) was selected as the response indicator of drought to assess the quantitative impact of drought on Inner Mongolia grassland based on the Standardized Precipitation Index (SPI) and BIOME-BGC model. The framework consists of six main steps: 1) clearly defining drought scenarios, such as moderate, severe and extreme drought; 2) selecting an appropriate indicator of drought impact; 3) selecting an appropriate ecosystem model and verifying its capabilities, calibrating the bias and assessing the uncertainty; 4) assigning a level of unacceptable impact of drought on the indicator; 5) determining the response of the indicator to drought and normal weather state under global-change; and 6) investigating the unacceptable impact of drought at different spatial scales. We found NPP losses assessed using the new framework were more sensitive to drought and had higher precision than the long-term average method. Moreover, the total and average losses of NPP are different in different grassland types during the drought years from 1961-2009. NPP loss was significantly increased along a gradient of increasing drought levels. Meanwhile, NPP loss variation under the same drought level was different in different grassland types. The operational framework was particularly suited for integrative assessing the effects of different drought events and long-term droughts at multiple spatial scales, which provided essential insights for sciences and societies that must develop coping strategies for ecosystems for such events. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Effects of forest expansion on mountain grassland

    DEFF Research Database (Denmark)

    Guidi, Claudia; Magid, Jakob; Rodeghiero, Mirco

    2014-01-01

    Background and aims. Grassland abandonment followed by forest succession is the dominant land-use change in the European Alps. We studied the impact of current forest expansion on mountain grassland on changes in physical soil organic carbon (SOC) fractions along a land-use and management gradient......, focusing on changes in aggregate stability and particulate organic matter (POM). Methods. Four successional stages were investigated: managed grassland, two transitional phases in which grassland abandonment led to colonization by Picea abies (L.) Karst., and old mixed forest dominated by Fagus sylvatica L....... Results. The dimension of aggregates assessed by aggregate size fractionation tended to increase, whereas SOC allocation to stable aggregates assessed by sizedensity fractionation decreased following conversion of grassland to forest (e.g. from 81 to 59 % in the 0–5 cm layer). The amount of SOC stored...

  11. Conserving the Brazilian semiarid (Caatinga) biome under climate change

    DEFF Research Database (Denmark)

    Oliveira, Guilherme de; Bastos Araujo, Miguel; Rangel, Thiago Fernado

    2012-01-01

    to assess changes in climate suitability across individual species ranges, ensemble forecasting was used based on seven bioclimatic envelope models, three atmosphere–ocean general circulation models, and two greenhouse emission gas scenarios for 2020, 2050, and 2080. We found that most species will gain...... additional threats to the biome’s biodiversity. Here, we ask if the remnants of natural vegetation in Caatinga biome, where endemic terrestrial vertebrate species occur, are likely to retain more climatic suitability under climate change scenarios than other less pristine areas of the biome. In order......The Caatinga is a semiarid biome of the northeast of Brazil with only 1 % of its territory currently conserved. The biome’s biodiversity is highly threatened due to exposure to land conversion for agricultural and cattle ranch. Climate forecasts predict increases in aridity, which could pose...

  12. Remotely sensed phenology for mapping biomes and vegetation functional types

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2009-07-01

    Full Text Available clearly captured in Fig. 3. The majority of the pixels in the Savanna have a start of growing season in late October, midposition in February and end in June (Fig. 3). In contrast, the winter rainfall Succulent Karoo have a start of growing season... initially split the biomes based on vegetation production and then by the seasonality of growth IV - 1035 (Fig. 4). The three arid biomes (Desert, Succulent and Nama Figure 3. Frequency histograms of the mean START, midposition (MID) and END date...

  13. La prosodia como identificador biométrico

    OpenAIRE

    Farrús i Cabeceran, Mireia

    2011-01-01

    La biometría tiene como objetivo el reconocimiento de personas mediante uno o más identificadores biométricos como la voz, la cara o las huellas dactilares, entre otros. Gracias a la buena aceptación social y el poco intrusismo en los individuos, la voz ha sido, tradicionalmente, uno de los identificadores más utilizados en los sistemas biométricos. Estos sistemas de reconocimiento basados en la voz utilizan, habitualmente, características relacionadas con el espectro de la voz. No obstante, ...

  14. The role of phytophysiognomies and seasonality on the structure of ground-dwelling anuran (Amphibia) in the Pampa biome, Southern Brazil.

    Science.gov (United States)

    Maragno, Franciéle P; Santos, Tiago G; Cechin, Sonia Z

    2013-09-01

    Considering that habitat use by amphibians is related both with climate and environmental features, we tested the hypothesis that anuran assemblages found in different phytophysiognomies and in different seasons vary in structure. Additionally, we searched for species which can be indicators of habitat and seasons. The study was conducted in the Pampa biome, southern Brazil. Sampling was done through pitfall traps placed in three phytophysiognomies: grassland, ecotone grassland/forest; and forest. The seasonality factor was created by grouping months in warn and cold seasons. Sixteen species were found and the assemblages were influenced both by phytophysiognomies and climatic seasonality. In a paired comparison, the three phytophysiognomies differed in structure of assemblage from each other. Physalaemus henselii, P. riograndensis, Pseudopaludicola falcipes and Pseudis minuta were indicators of ecotone. Leptodactylus gracilis and Physalaemus biligonigerus were indicators of grassland. None species was indicator of forest. Most of the species were indicators of warm season: Elachistocleis bicolor, Leptodactylus fuscus, L. gracilis, L. latinasus, L. latrans, L. mystacinus, Physalaemus biligonigerus, P. cuvieri and Pseudis minuta. None species was indicator of cold season. We found that even for species of open areas, as Pampa, heterogeneous phytophysiognomies are important for maintaining abundance and constancy of populations of anuran.

  15. Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups.

    Science.gov (United States)

    Reich, Peter B; Walters, Michael B; Ellsworth, David S; Vose, James M; Volin, John C; Gresham, Charles; Bowman, William D

    1998-05-01

    Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (R d ) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (A max ). However, it is not known whether such scaling, if it exists, is similar among disparate biomes and plant functional types. We tested this idea by examining the interspecific relationships between R d measured at a standard temperature and leaf life-span, N, SLA and A max for 69 species from four functional groups (forbs, broad-leafed trees and shrubs, and needle-leafed conifers) in six biomes traversing the Americas: alpine tundra/subalpine forest, Colorado; cold temperate forest/grassland, Wisconsin; cool temperate forest, North Carolina; desert/shrubland, New Mexico; subtropical forest, South Carolina; and tropical rain forest, Amazonas, Venezuela. Area-based R d was positively related to area-based leaf N within functional groups and for all species pooled, but not when comparing among species within any site. At all sites, mass-based R d (R d-mass ) decreased sharply with increasing leaf life-span and was positively related to SLA and mass-based A max and leaf N (leaf N mass ). These intra-biome relationships were similar in shape and slope among sites, where in each case we compared species belonging to different plant functional groups. Significant R d-mass -N mass relationships were observed in all functional groups (pooled across sites), but the relationships differed, with higher R d at any given leaf N in functional groups (such as forbs) with higher SLA and shorter leaf life-span. Regardless of biome or functional group, R d-mass was well predicted by all combinations of leaf life-span, N mass and/or SLA (r 2 ≥ 0.79, P morphological, chemical and metabolic traits.

  16. Variability of annual CO2 exchange from Dutch grasslands

    NARCIS (Netherlands)

    Jacobs, C.M.J.; Jacobs, A.F.G.; Bosveld, F.C.; Hendriks, D.M.D.; Hensen, A.; Kroon, P.; Moors, E.J.; Nol, L.; Schrier-Uijl, A.P.; Veenendaal, E.M.

    2007-01-01

    An intercomparison is made of the Net Ecosystem Exchange of CO2, NEE, for eight Dutch grassland sites: four natural grasslands, two production grasslands and two meteorological stations within a rotational grassland region. At all sites the NEE was determined during at least 10 months per site,

  17. Satellite-based assessment of grassland yields

    Science.gov (United States)

    Grant, K.; Siegmund, R.; Wagner, M.; Hartmann, S.

    2015-04-01

    Cutting date and frequency are important parameters determining grassland yields in addition to the effects of weather, soil conditions, plant composition and fertilisation. Because accurate and area-wide data of grassland yields are currently not available, cutting frequency can be used to estimate yields. In this project, a method to detect cutting dates via surface changes in radar images is developed. The combination of this method with a grassland yield model will result in more reliable and regional-wide numbers of grassland yields. For the test-phase of the monitoring project, a study area situated southeast of Munich, Germany, was chosen due to its high density of managed grassland. For determining grassland cutting robust amplitude change detection techniques are used evaluating radar amplitude or backscatter statistics before and after the cutting event. CosmoSkyMed and Sentinel-1A data were analysed. All detected cuts were verified according to in-situ measurements recorded in a GIS database. Although the SAR systems had various acquisition geometries, the amount of detected grassland cut was quite similar. Of 154 tested grassland plots, covering in total 436 ha, 116 and 111 cuts were detected using CosmoSkyMed and Sentinel-1A radar data, respectively. Further improvement of radar data processes as well as additional analyses with higher sample number and wider land surface coverage will follow for optimisation of the method and for validation and generalisation of the results of this feasibility study. The automation of this method will than allow for an area-wide and cost efficient cutting date detection service improving grassland yield models.

  18. Karoo biome: a preliminary sythesis. Part 1 - physical environment

    CSIR Research Space (South Africa)

    Cowling, RM

    1986-01-01

    Full Text Available . It is a multi-authored publication covering a wide range of topics. This first volume summarizes what is currently known on the physical environment of the biome; namely geology, soils, climate, hydrology, geohydrology and soil erosion. Other aspects...

  19. Importance of soil-water to the Caatinga biome, Brazil

    NARCIS (Netherlands)

    Alves Rodrigues Pinheiro, Everton; Metselaar, Klaas; Jong van Lier, de Quirijn; Araújo, de José Carlos

    2016-01-01

    Northeastern Brazil is hydrologically characterized by recurrent droughts leading to a highly vulnerable natural water resource system. The region contains the Caatinga biome, covering an area of approximately 800000km2. To increase insight in water balance components for this sparsely

  20. South African Red Data Book: Plants - fynbos and Karoo biomes

    CSIR Research Space (South Africa)

    Hall, AV

    1985-01-01

    Full Text Available In this report a list is given of 1 808 rare, threatened and recently extinct plants in the fynbos and karoo biomes in the Cape Province of South Africa. The area covers the south-western and southern Cape, Namaqualand and the Karoo. Following...

  1. Climate control of terrestrial carbon exchange across biomes and continents

    Science.gov (United States)

    Chuixiang Yi; Daniel Ricciuto; Runze Li; John Wolbeck; Xiyan Xu; Mats Nilsson; John Frank; William J. Massman

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes...

  2. Climate control of terrestrial carbon exchange across biomes and continents

    Czech Academy of Sciences Publication Activity Database

    Yi, C.; Ricciuto, D.; Marek, Michal V.

    2010-01-01

    Roč. 5, č. 3 (2010), s. 034007 ISSN 1748-9326 Institutional research plan: CEZ:AV0Z60870520 Keywords : NEE * climate control * terrestrial carbon sequestration * temperature * dryness * eddy flux * biomes * photosynthesis * respiration * global carbon cycle Subject RIV: EH - Ecology, Behaviour Impact factor: 3.049, year: 2010

  3. Anthropogenic biomes: a key contribution to earth-system science

    Science.gov (United States)

    Lilian Alessa; F. Stuart Chapin

    2008-01-01

    Human activities now dominate most of the ice-free terrestrial surface. A recent article presents a classification and global map of human-influenced biomes of the world that provides a novel and potentially appropriate framework for projecting changes in earth-system dynamics.

  4. Structure of Drosophilidae Assemblage (Insecta, Diptera in Pampa Biome (São Luiz Gonzaga, RS

    Directory of Open Access Journals (Sweden)

    Jean Lucas Poppe

    2012-01-01

    Full Text Available The Brazilian Pampa (the southernmost end of the country is currently a highly modified environment because of increasing agricultural activities. In many places, only small parts of grasslands remain inside an agricultural landscape. Drosophilidae (Diptera have been widely used as a potential bioindicators to monitor the effects of anthropogenic changes in natural environments. However, the fauna of Drosophilidae in the Pampa Biome from natural and disturbed environments, still remains largely unknown. The present study represents one of the first attempts to fill this gap, showing results from monthly collections in the municipality of São Luiz Gonzaga (28º24'28"S, 54º57'39"W, in the Brazilian Pampa. A species inventory was carried out in two contrasting environments, an urban zone and a forest remnant (rural zone. In both areas banana-baited traps were used to capture adult drosophilids. The identification was made using external morphology and male terminalia. In total, 13,379 drosophilids were analyzed (rural zone: N = 8,812 and Sobs = 25; urban zone: N = 4,567 and Sobs = 16. In the present study, 16 (60% out of 26 species were found exclusively or preferentially in the forest. The period of highest richness was between the months of June to November (roughly winter and spring, and the period of lowest richness was from December to May (roughly summer and autumn. An analysis of cluster by the Coefficient of Jaccard showed that species composition slightly changes when the period of the year with higher temperatures (from January to May is compared with the period with lower temperatures (from June to October. The species abundances were also highly affected by seasonality, as revealed by the Morisita Index, since the samples clustered into similar groups in consecutive periods and in the same season, showing the seasonal preference of some species. The time component was a determinant in the diversity of the assemblage, surpassing the

  5. User's Guide to Biome Information from the United States International Biological Program (IBP). First Edition.

    Science.gov (United States)

    Hinckley, A. Dexter; Haug, Peter T.

    This publication is a guide to the biome research conducted under the International Biological Program. The guide lists biome researchers by interest and by biome as well as a central list. A site list, map, information sources section reporting abstracts, bibliographies, journals, books, evaluations, and data books are also included. Three…

  6. The effect of heterogeneous landscape dynamics on ecotone types at two convergent semi-arid biomes

    Science.gov (United States)

    Landscapes in biome transition zones consist of a mosaic of patches dominated or codominated by species from adjacent biomes. Shifts in the vegetation composition and dynamics of a biome transition zone depend upon the underlying patch dynamics of the ecotones between these dominant species. Landsca...

  7. Importance of ecotone type to landscape dynamics at biome transition zones

    Science.gov (United States)

    Landscapes in biome transition zones consist of a mosaic of patches dominated or codominated by species from adjacent biomes. Shifts in the vegetation composition and dynamics of a biome transition zone depend upon the underlying patch dynamics of the ecotones between these dominant species. Landsc...

  8. Combining in situ and laboratory measurements of soil-atmosphere carbonyl sulfide fluxes from four different biomes across Europe

    Science.gov (United States)

    Kitz, Florian; Gomez-Brandon, Maria; Hammerle, Albin; Spielmann, Felix M.; Insam, Heribert; Ibrom, Andreas; Migliavacca, Mirco; Moreno, Gerardo; Noe, Steffen M.; Wohlfahrt, Georg

    2017-04-01

    Flux partitioning, the quantification of photosynthesis and respiration, is a major uncertainty in modelling the carbon cycle and in times when robust models are needed to assess future global changes a persistent problem. A promising new approach is to derive gross primary production (GPP) from measurements of the carbonyl sulfide (COS) flux, the most abundant sulfur-containing trace gas in the atmosphere, with a mean concentration of about 500 pptv in the troposphere. This is possible because COS and CO2 enter the leaf via a similar pathway and are processed by the same enzyme (carbonic anhydrase). A prerequisite for using COS as a proxy for photosynthesis is a robust estimation of all non-leaf sources and sinks in an ecosystem. Past studies described soils either as a sink or source, depending on their properties like soil temperature and soil water content. In 2016 we conducted field campaigns in Austria (managed temperate mountain grassland), Spain (savannah), Denmark (temperate beech forest) and Estonia (hemiboreal forest) to estimate the soil-atmosphere COS fluxes under ambient conditions in different biomes. We used self-built fused silica soil chambers to avoid COS emissions from built-in materials and to assess the impact of radiation. At the grassland sites (Austria, Spain) vegetation was removed below the chambers, therefor more radiation reached the soil surface compared to natural conditions. The grassland sites were characterized by highly positive COS fluxes during daytime and COS fluxes around zero during nighttime. In contrast, the soils at the forest sites (Denmark, Estonia), characterized by less radiation on the soil surface, acted as a sink for COS. The impact of other abiotic factors, like soil water content and soil temperature, varied between the ecosystems. In addition to the field measurements soil and litter samples were taken at the study sites and used to measure COS fluxes under controlled conditions in the lab. Results from the

  9. Soil disturbance as a grassland restoration measure

    DEFF Research Database (Denmark)

    Schnoor, Tim; Bruun, Hans Henrik; Olsson, Pål Axel

    2015-01-01

    Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success...... to experimental disturbance treatments (ploughing or rotavation), and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration...

  10. Effect of land use change on methane oxidation in temperate forest and grassland soils

    Energy Technology Data Exchange (ETDEWEB)

    Ojima, D.S.; Valentine, D.W.; Mosier, A.R.; Parton, W.J.; Schimel, D.S. (Colorado State University, Fort Collins, CO (USA). Natural Resources Ecology Lab.)

    Evidence is accumulating that land use changes and other human activity during the past 100 to 200 years have contributed to decreased CH[sub 4] oxidation in the soil. Increased N additions to temperate forest soils in the northeastern United States decreased CH[sub 4] uptake by 30 to 60%, and increased N fertilization and conversion to cropland in temperate grasslands decreased CH[sub 4] uptake by 30 to 75%. Using these data, a series of calculations were made to estimate the impact of land use and management changes which have altered soil, the CH[sub 4] sink in temperate forest and grassland ecosystems. As the atmospheric mixing ratio of CH[sub 4] has increased during the past 150 y, the temperate CH[sub 4] sink has risen from approximately 8 Tg y[sup -1] to 27 Tg y[sup -1], assuming no loss of land cover to cropland conversion. The net effect of intensive land cover changes and extensive chronic disturbance (i.e., increased atmospheric N deposition) to these ecosystems have resulted in about 30% reduction in the CH[sub 4] budget even more as atmospheric CH[sub 4] concentrations increase and as a result of further disturbance to other biomes. Without accounting for this approximately 20 Tg y[sup -1] temperate soil sink, the atmospheric CH[sub 4] concentration would be increasing about 1.5 times the current rate. 39 refs., 2 figs., 1 tab.

  11. The ecological and economic consequences of changing land use in the southern Drakensberg grasslands, South Africa

    Directory of Open Access Journals (Sweden)

    JK Turpie

    2014-05-01

    Full Text Available The grassland biome of the southern Drakensberg region of South Africa is characterized by a relatively rich floral biodiversity, including a high level of endemics.  Land use in the area was traditionally dominated by livestock ranching based mainly on indigenous grassland that conserved biodiversity to some degree.  Currently however, market demands and risk factors are shifting land use in the area to a matrix of beef, cropping, dairy and particularly, towards plantation forestry.  A spreadsheet model was constructed to understand how expected land use conversion will likely influence the biodiversity, and consequently, the total economic value (TEV of the area.  Six scenarios of increasing dairy and forestry intensification were modelled that incorporated biophysical and legal constraints to development.  Results indicate that enhanced development is likely to have significant negative biodiversity impacts including the reduction of the alpha diversity of the indigenous plants in the region, a diminished local invertebrate diversity, an increase in invasions, and could also jeopardize the long term survival of the rare Wattled Crane and Oribi.  Furthermore, while the direct use value derived from agriculture and forestry increases with increasing development, its negative influence on the indirect value of water runoff, by far the greatest value of the area, is sufficient to potentially offset the benefits.  Other major direct-use, indirect-use, option and existence values are also considered.

  12. Population Genetic Structure of Cnesterodon decemmaculatus (Poeciliidae): A Freshwater Look at the Pampa Biome in Southern South America.

    Science.gov (United States)

    Ramos-Fregonezi, Aline M C; Malabarba, Luiz R; Fagundes, Nelson J R

    2017-01-01

    The Pampas is a Neotropical biome formed primarily by low altitude grasslands and encompasses the southernmost portion of Brazil, Uruguay, and part of Argentina. Despite the high level of endemism, and its significant environmental heterogeneity, Pampean species are underrepresented in phylogeographic studies, especially aquatic organisms. The Pampean hydrological system resulted from a long history of tectonism, climate, and sea level changes since the Neogene. In this study, we examined the population genetic structure of Cnesterodon decemmaculatus , a freshwater fish species that occurs throughout most of the Pampa biome. We characterized mitochondrial and autosomal genetic lineages in populations sampled from Southern Brazil and Uruguay to investigate (1) the correspondence between current drainage systems and evolutionary lineages, (2) the demographic history for each genetic lineage, and (3) the temporal depth of these lineages. Overall, we found that the major evolutionary lineages in this species are strongly related to the main Pampean drainage systems, even though stream capture events may have affected the distribution of genetic lineages among drainages. There was evidence for recent population growth in the lineages occupying drainages closest to the shore, which may indicate the effect of quaternary sea-level changes. In general, divergence time estimates among evolutionary lineages were shallow, ranging from 20,000 to 800,000 years before present, indicating a geologically recent history for this group, as previously reported in other Pampean species. A Bayesian phylogeographical reconstruction suggested that an ancestral lineage probably colonized the Uruguay River Basin, and then expanded throughout the Pampas. This evolutionary scenario may represent useful starting models for other freshwater species having a similar distribution.

  13. Scale and the isotopic record of C4 plants in pedogenic carbonate: from the biome to the rhizospere.

    Energy Technology Data Exchange (ETDEWEB)

    Monger, Dr. H Curtis [New Mexico State University, Las Cruces; Cole, David R [ORNL; Buck, Dr. Brenda [University of Nevada, Las Vegas; Gallegos, Robert [Sant fe Water Division

    2009-01-01

    The 13C/12C ratio in pedogenic carbonate (i.e., CaCO3 formed in soil) is a significant tool for investigating C4 biomes of the past. However, the paleoecological meaning of d13C values in pedogenic carbonate can change with the scale at which one considers the data. We describe studies of modern soils, fossil soils, and vegetation change in the Chihuahuan Desert of North America and elsewhere that reveal four scales important for paleoecologic interpretations. (1) At the broadest scale, the biome scale (hundreds to millions of km2), an isotopic record interpreted as C3 vegetation replacing C4 grasslands may indicate invading C3 woody shrubs instead of expanding C3 forests (a common interpretation). (2) At the landscape scale (several tens of m2 to hundreds of km2), the accuracy of scaling up paleoclimatic interpretations to a regional level is affected by the landform containing the isotopic record. (3) At the soil-profile scale (cm2 to m2), soil profiles with multiple generations of carbonate mixed together have a lower-resolution paleoecologic record than soil profiles repeatedly buried. (4) At the rhizosphere scale (lm2 to cm2), carbonate formed on roots lack the 14 17 enrichment observed at broader scales, revealing different fractionation processes at different scales. A multi-scale approach in dealing with d13C in pedogenic carbonate will increase the accuracy of paleoecologic interpretations and understanding of soil geomorphic climatic interactions that affect boundaries between C4 and C3 vegetation.

  14. Population Genetic Structure of Cnesterodon decemmaculatus (Poeciliidae: A Freshwater Look at the Pampa Biome in Southern South America

    Directory of Open Access Journals (Sweden)

    Aline M. C. Ramos-Fregonezi

    2017-12-01

    Full Text Available The Pampas is a Neotropical biome formed primarily by low altitude grasslands and encompasses the southernmost portion of Brazil, Uruguay, and part of Argentina. Despite the high level of endemism, and its significant environmental heterogeneity, Pampean species are underrepresented in phylogeographic studies, especially aquatic organisms. The Pampean hydrological system resulted from a long history of tectonism, climate, and sea level changes since the Neogene. In this study, we examined the population genetic structure of Cnesterodon decemmaculatus, a freshwater fish species that occurs throughout most of the Pampa biome. We characterized mitochondrial and autosomal genetic lineages in populations sampled from Southern Brazil and Uruguay to investigate (1 the correspondence between current drainage systems and evolutionary lineages, (2 the demographic history for each genetic lineage, and (3 the temporal depth of these lineages. Overall, we found that the major evolutionary lineages in this species are strongly related to the main Pampean drainage systems, even though stream capture events may have affected the distribution of genetic lineages among drainages. There was evidence for recent population growth in the lineages occupying drainages closest to the shore, which may indicate the effect of quaternary sea-level changes. In general, divergence time estimates among evolutionary lineages were shallow, ranging from 20,000 to 800,000 years before present, indicating a geologically recent history for this group, as previously reported in other Pampean species. A Bayesian phylogeographical reconstruction suggested that an ancestral lineage probably colonized the Uruguay River Basin, and then expanded throughout the Pampas. This evolutionary scenario may represent useful starting models for other freshwater species having a similar distribution.

  15. Scale and the isotopic record of C4 plants in pedogenic carbonate: from the biome to the rhizosphere

    Energy Technology Data Exchange (ETDEWEB)

    Monger, Dr. H Curtis [New Mexico State University, Las Cruces; Cole, David [Ohio State University; Buck, Dr. Brenda [University of Nevada, Las Vegas; Gallegos, Robert [Sant fe Water Division

    2009-01-01

    The 13C/12C ratio in pedogenic carbonate (i.e., CaCO3 formed in soil) is a significant tool for investigating C4 biomes of the past. However, the paleoecological meaning of d13C values in pedogenic carbonate can change with the scale at which one considers the data. We describe studies of modern soils, fossil soils, and vegetation change in the Chihuahuan Desert of North America and elsewhere that reveal four scales important for paleoecologic interpretations. (1) At the broadest scale, the biome scale (hundreds to millions of km2), an isotopic record interpreted as C3 vegetation replacing C4 grasslands may indicate invading C3 woody shrubs instead of expanding C3 forests (a common interpretation). (2) At the landscape scale (several tens of m2 to hundreds of km2), the accuracy of scaling up paleoclimatic interpretations to a regional level is affected by the landform containing the isotopic record. (3) At the soil-profile scale (cm2 to m2), soil profiles with multiple generations of carbonate mixed together have a lower-resolution paleoecologic record than soil profiles repeatedly buried. (4) At the rhizosphere scale (lm2 to cm2), carbonate formed on roots lack the 14 17 enrichment observed at broader scales, revealing different fractionation processes at different scales. A multi-scale approach in dealing with d13C in pedogenic carbonate will increase the accuracy of paleoecologic interpretations and understanding of soil geomorphic climatic interactions that affect boundaries between C4 and C3 vegetation.

  16. Biom stepí: Severopanonské stepi

    Czech Academy of Sciences Publication Activity Database

    Buček, A.; Lacina, Jan

    -, č. 17 (2006), s. 2-6 ISSN 1213-0699 Grant - others:EU(XE) Program Evropské unie LIFE-Nature Institutional research plan: CEZ:AV0Z30860518 Keywords : Pannonian steppe grasslands * conservation of the nature * South Moravia Subject RIV: EH - Ecology, Behaviour

  17. Land use change and ecosystem service provision in Pampas and Campos grasslands of southern South America

    Science.gov (United States)

    Modernel, P.; Rossing, W. A. H.; Corbeels, M.; Dogliotti, S.; Picasso, V.; Tittonell, P.

    2016-11-01

    New livestock production models need to simultaneously meet the increasing global demand for meat and preserve biodiversity and ecosystem services. Since the 16th century beef cattle has been produced on the Pampas and Campos native grasslands in southern South America, with only small amounts of external inputs. We synthesised 242 references from peer-reviewed and grey literature published between 1945 and mid-2015 and analysed secondary data to examine the evidence on the ecosystem services provided by this grassland biodiversity hotspot and the way they are affected by land use changes and their drivers. The analysis followed the requirements of systematic review from the PRISMA statement (Moher et al 2009 Acad. Clin. Ann. Intern. Med. 151 264-9). The Pampas and Campos provide feed for 43 million heads of cattle and 14 million sheep. The biome is habitat of 4000 native plant species, 300 species of birds, 29 species of mammals, 49 species of reptiles and 35 species of amphibians. The soils of the region stock 5% of the soil organic carbon of Latin America on 3% of its area. Driven by high prices of soybean, the soybean area increased by 210% between 2000 and 2010, at the expense of 2 million ha (5%) of native grassland, mostly in the Pampas. Intensification of livestock production was apparent in two spatially distinct forms. In subregions where cropping increased, intensification of livestock production was reflected in an increased use of grains for feed as part of feedlots. In subregions dominated by native grasslands, stocking rates increased. The review showed that land use change and grazing regimes with low forage allowances were predominantly associated with negative effects on ecosystem service provision by reducing soil organic carbon stocks and the diversity of plants, birds and mammals, and by increasing soil erosion. We found little quantitative information on changes in the ecosystem services water provision, nutrient cycling and erosion control

  18. BIOME: A browser-aware search and order system

    Science.gov (United States)

    Grubb, Jon W.; Jennings, Sarah V.; Yow, Teresa G.; Daughterty, Patricia F.

    1996-01-01

    The Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC), which is associated with NASA's Earth Observing System Data and Information System (EOSDIS), provides access to a large number of tabular and imagery datasets used in ecological and environmental research. Because of its large and diverse data holdings, the challenge for the ORNL DAAC is to help users find data of interest from the hundreds of thousands of files available at the DAAC without overwhelming them. Therefore, the ORNL DAAC developed the Biogeochemical Information Ordering Management Environment (BIOME), a search and order system for the World Wide Web (WWW). The WWW provides a new vehicle that allows a wide range of users access to the data. This paper describes the specialized attributes incorporated into BIOME that allow researchers easy access to an otherwise bewildering array of data products.

  19. Effects of grassland management on the emission of methane from grassland on peat soils

    Energy Technology Data Exchange (ETDEWEB)

    Van Dasselaar, A. [Dept. of Soil Science and Plant Nutrition, Wageningen Agricultural Univ. (Netherlands); Oenema, O. [NMI, Wageningen (Netherlands)

    1995-11-01

    Net methane (CH{sub 4}) emissions from managed grassland on peat soils in the Netherlands have been monitored with vented closed flux chambers in the period January - June 1994. Net CH{sub 4} emissions from two intensively managed grasslands were low, in general less than 0.1 mg CH{sub 4} m{sup -2} d{sup -l}. On these sites, the effect of management was negligibly small. CH{sub 4} emission from three extensively managed grasslands in a nature preserve ranged from 0 to 185 mg CH{sub 4} m{sup -2} d{sup -l}. The results presented here indicate that CH{sub 4} emissions are 2-3 orders of magnitude higher on extensively managed grasslands than on intensively managed grasslands. 2 figs., 6 refs.

  20. Effects of climate and lifeform on dry matter yield (epsilon) from simulations using BIOME BGC. [ecosystem process model for vegetation biomass production using daily absorbed photosynthetically active radiation

    Science.gov (United States)

    Hunt, E. R., Jr.; Running, Steven W.

    1992-01-01

    An ecosystem process simulation model, BIOME-BGC, is used in a sensitivity analysis to determine the factors that may cause the dry matter yield (epsilon) and annual net primary production to vary for different ecosystems. At continental scales, epsilon is strongly correlated with annual precipitation. At a single location, year-to-year variation in net primary production (NPP) and epsilon is correlated with either annual precipitation or minimum air temperatures. Simulations indicate that forests have lower epsilon than grasslands. The most sensitive parameter affecting forest epsilon is the total amount of living woody biomass, which affects NPP by increasing carbon loss by maintenance respiration. A global map of woody biomass should significantly improve estimates of global NPP using remote sensing.

  1. Parameterisation of Biome BGC to assess forest ecosystems in Africa

    Science.gov (United States)

    Gautam, Sishir; Pietsch, Stephan A.

    2010-05-01

    African forest ecosystems are an important environmental and economic resource. Several studies show that tropical forests are critical to society as economic, environmental and societal resources. Tropical forests are carbon dense and thus play a key role in climate change mitigation. Unfortunately, the response of tropical forests to environmental change is largely unknown owing to insufficient spatially extensive observations. Developing regions like Africa where records of forest management for long periods are unavailable the process-based ecosystem simulation model - BIOME BGC could be a suitable tool to explain forest ecosystem dynamics. This ecosystem simulation model uses descriptive input parameters to establish the physiology, biochemistry, structure, and allocation patterns within vegetation functional types, or biomes. Undocumented parameters for larger-resolution simulations are currently the major limitations to regional modelling in African forest ecosystems. This study was conducted to document input parameters for BIOME-BGC for major natural tropical forests in the Congo basin. Based on available literature and field measurements updated values for turnover and mortality, allometry, carbon to nitrogen ratios, allocation of plant material to labile, cellulose, and lignin pools, tree morphology and other relevant factors were assigned. Daily climate input data for the model applications were generated using the statistical weather generator MarkSim. The forest was inventoried at various sites and soil samples of corresponding stands across Gabon were collected. Carbon and nitrogen in the collected soil samples were determined from soil analysis. The observed tree volume, soil carbon and soil nitrogen were then compared with the simulated model outputs to evaluate the model performance. Furthermore, the simulation using Congo Basin specific parameters and generalised BIOME BGC parameters for tropical evergreen broadleaved tree species were also

  2. Softball Games Bring NCI and Leidos Biomed Employees Together | Poster

    Science.gov (United States)

    NCI and Leidos Biomed employees took to the fields at Nallin Pond for the third annual slow-pitch softball games on August 26. The series attracted 54 employees who were divided into four teams, Red, Blue, Gray, and White, and they were cheered on by about 40 enthusiastic spectators. In the first set of games, the Gray team defeated the Blue team, 15–8, and the White team

  3. Combining multiple ecosystem productivity measurements to constrain carbon uptake estimates in semiarid grasslands and shrublands

    Science.gov (United States)

    Maurer, G. E.; Krofcheck, D. J.; Collins, S. L.; Litvak, M. E.

    2016-12-01

    Recent observational and modeling studies have indicated that semiarid ecosystems are more dynamic contributors to the global carbon budget than once thought. Semiarid carbon fluxes, however, are generally small, with high interannual and spatial variability, which suggests that validating their global significance may depend on examining multiple productivity measures and their associated uncertainties and inconsistencies. We examined ecosystem productivity from eddy covariance (NEE), harvest (NPP), and terrestrial biome models (NEPm) at two very similar grassland sites and one creosote shrubland site in the Sevilleta National Wildlife Refuge of central New Mexico, USA. Our goal was to assess site and methodological correspondence in annual carbon uptake, patterns of interannual variability, and measurement uncertainty. One grassland site was a perennial carbon source losing 30 g C m-2 per year on average, while the other two sites were carbon sources or sinks depending on the year, with average net uptake of 5 and 25 g C m-2 per year at the grassland and shrubland site, respectively. Uncertainty values for cumulative annual NEE overlapped between the three sites in most years. When combined, aboveground and belowground annual NPP measurements were 15% higher than annual NEE values and did not confirm a loss of carbon at any site in any year. Despite differences in mean site carbon balance, year-to-year changes in cumulative annual NEE and NPP were similar at all sites with years 2010 and 2013 being favorable for carbon uptake and 2011 and 2012 being unfavorable at all sites. Modeled NEPm data for a number of nearby grid cells reproduced only a fraction of the observed range in carbon uptake and its interannual variability. These three sites are highly similar in location and climate and multiple carbon flux measurements confirm the high interannual variability in carbon flux. The exact magnitude of these fluxes, however, remains difficult to discern.

  4. Plutonium in a grassland ecosystem

    International Nuclear Information System (INIS)

    Little, C.A.

    1976-08-01

    A study was made of plutonium contamination of grassland at the Rocky Flats plant northwest of Denver, Colorado. Of interest were: the definition of major plutonium-containing ecosystem compartments; the relative amounts in those compartments; how those values related to studies done in other geographical areas; whether or not the predominant isotopes, 238 Pu and 239 Pu, behaved differently; and what mechanisms might have allowed for the observed patterns of contamination. Samples of soil, litter, vegetation, arthropods, and small mammals were collected for Pu analysis and mass determination from each of two macroplots. Small aliquots (5 g or less) were analyzed by a rapid liquid scintillation technique and by alpha spectrometry. Of the compartments sampled, greater than 99 percent of the total plutonium was contained in the soil and the concentrations were significantly inversely correlated with distance from the contamination source, depth of the sample, and particle size of the sieved soil samples. The soil data suggested that the distribution of contamination largely resulted from physical transport processes

  5. Constrained variability of modeled T:ET ratio across biomes

    Science.gov (United States)

    Fatichi, Simone; Pappas, Christoforos

    2017-07-01

    A large variability (35-90%) in the ratio of transpiration to total evapotranspiration (referred here as T:ET) across biomes or even at the global scale has been documented by a number of studies carried out with different methodologies. Previous empirical results also suggest that T:ET does not covary with mean precipitation and has a positive dependence on leaf area index (LAI). Here we use a mechanistic ecohydrological model, with a refined process-based description of evaporation from the soil surface, to investigate the variability of T:ET across biomes. Numerical results reveal a more constrained range and higher mean of T:ET (70 ± 9%, mean ± standard deviation) when compared to observation-based estimates. T:ET is confirmed to be independent from mean precipitation, while it is found to be correlated with LAI seasonally but uncorrelated across multiple sites. Larger LAI increases evaporation from interception but diminishes ground evaporation with the two effects largely compensating each other. These results offer mechanistic model-based evidence to the ongoing research about the patterns of T:ET and the factors influencing its magnitude across biomes.

  6. Preliminary Research on Grassland Fine-classification Based on MODIS

    International Nuclear Information System (INIS)

    Hu, Z W; Zhang, S; Yu, X Y; Wang, X S

    2014-01-01

    Grassland ecosystem is important for climatic regulation, maintaining the soil and water. Research on the grassland monitoring method could provide effective reference for grassland resource investigation. In this study, we used the vegetation index method for grassland classification. There are several types of climate in China. Therefore, we need to use China's Main Climate Zone Maps and divide the study region into four climate zones. Based on grassland classification system of the first nation-wide grass resource survey in China, we established a new grassland classification system which is only suitable for this research. We used MODIS images as the basic data resources, and use the expert classifier method to perform grassland classification. Based on the 1:1,000,000 Grassland Resource Map of China, we obtained the basic distribution of all the grassland types and selected 20 samples evenly distributed in each type, then used NDVI/EVI product to summarize different spectral features of different grassland types. Finally, we introduced other classification auxiliary data, such as elevation, accumulate temperature (AT), humidity index (HI) and rainfall. China's nation-wide grassland classification map is resulted by merging the grassland in different climate zone. The overall classification accuracy is 60.4%. The result indicated that expert classifier is proper for national wide grassland classification, but the classification accuracy need to be improved

  7. Some Insights on Grassland Health Assessment Based on Remote Sensing

    Directory of Open Access Journals (Sweden)

    Dandan Xu

    2015-01-01

    Full Text Available Grassland ecosystem is one of the largest ecosystems, which naturally occurs on all continents excluding Antarctica and provides both ecological and economic functions. The deterioration of natural grassland has been attracting many grassland researchers to monitor the grassland condition and dynamics for decades. Remote sensing techniques, which are advanced in dealing with the scale constraints of ecological research and provide temporal information, become a powerful approach of grassland ecosystem monitoring. So far, grassland health monitoring studies have mostly focused on different areas, for example, productivity evaluation, classification, vegetation dynamics, livestock carrying capacity, grazing intensity, natural disaster detecting, fire, climate change, coverage assessment and soil erosion. However, the grassland ecosystem is a complex system which is formed by soil, vegetation, wildlife and atmosphere. Thus, it is time to consider the grassland ecosystem as an entity synthetically and establish an integrated grassland health monitoring system to combine different aspects of the complex grassland ecosystem. In this review, current grassland health monitoring methods, including rangeland health assessment, ecosystem health assessment and grassland monitoring by remote sensing from different aspects, are discussed along with the future directions of grassland health assessment.

  8. Some insights on grassland health assessment based on remote sensing.

    Science.gov (United States)

    Xu, Dandan; Guo, Xulin

    2015-01-29

    Grassland ecosystem is one of the largest ecosystems, which naturally occurs on all continents excluding Antarctica and provides both ecological and economic functions. The deterioration of natural grassland has been attracting many grassland researchers to monitor the grassland condition and dynamics for decades. Remote sensing techniques, which are advanced in dealing with the scale constraints of ecological research and provide temporal information, become a powerful approach of grassland ecosystem monitoring. So far, grassland health monitoring studies have mostly focused on different areas, for example, productivity evaluation, classification, vegetation dynamics, livestock carrying capacity, grazing intensity, natural disaster detecting, fire, climate change, coverage assessment and soil erosion. However, the grassland ecosystem is a complex system which is formed by soil, vegetation, wildlife and atmosphere. Thus, it is time to consider the grassland ecosystem as an entity synthetically and establish an integrated grassland health monitoring system to combine different aspects of the complex grassland ecosystem. In this review, current grassland health monitoring methods, including rangeland health assessment, ecosystem health assessment and grassland monitoring by remote sensing from different aspects, are discussed along with the future directions of grassland health assessment.

  9. Importance and functions of European grasslands.

    Science.gov (United States)

    Carlier, L; De Vliegher, A; Van Cleemput, O; Boeckx, P

    2005-01-01

    The European agricultural policy is not simple and needs to accommodate also social and environmental requirements. Grassland will continue to be an important form of land use in Europe, but with increased diversity in management objectives and systems used. Besides its role as basic nutrient for herbivores and ruminants grasslands have opportunities for adding value by exploiting positive health characteristics in animal products from grassland and through the delivery of environmental benefits. In fact grasslands contribute to a high degree to the struggle against erosion and to the regularizing of water regimes, to the purification of fertilizers and pesticides and to biodiversity. Finally they have aesthetic role and recreational function as far as they provide public access that other agricultural uses do not allow. But even for grassland it is very difficult to create a good frame for its different tasks (1) the provision of forage for livestock, (2) protection and conservation of soil and water resources, (3) furnishing a habitat for wildlife, both flora and fauna and (4) contribution to the attractiveness of the landscape. Nevertheless it is the only crop, able to fulfil so many tasks and to fit so many requirements.

  10. [Research progress and trend on grassland agroecology].

    Science.gov (United States)

    Ren, Jizhou; Li, Xianglin; Hou, Fujiang

    2002-08-01

    The connotation, progress, research frontiers and developmental trend of grassland agroecology are discussed in this paper. The interface theory, structure and function, coupling and discordance, and health assessment of grassland agroecosystems were recognized as the four research frontiers of the discipline. There exist three primary interfaces in a grassland agroecosystem, i.e., vegetation-site, grassland-animal and production-management. Research into a series of the ecological processes that occurred at these interfaces is the key to revealing the features of the system behavior. There are four sections in a grassland agroecosystem, i.e., pre-plant, plant, animal and post-biotic sections. System coupling and discordance are the two important concepts to describe interactions among the production sections. System coupling among the sections can lead to system improvement by exerting the potential of system capacity. Health of an ecosystem is a reflection of its structure and function, and health assessment is a measurement of its orderliness and service value.

  11. Plutonium in a grassland ecosystem

    International Nuclear Information System (INIS)

    Little, C.A.

    1976-01-01

    This study was concerned with plutonium contamination of grassland at the U.S. Energy Research and Development Administration Rocky Flats plant northwest of Denver, Colorado. Of interest were: the definition of major plutonium-containing ecosystem compartments; the relative amounts in those compartments; how those values related to studies done in other geogrphical areas; whether or not the predominant isotopes, 238 Pu and 239 Pu, behaved differently; and what mechanisms might have allowed for the observed patterns of contamination. Samples of soil, litter, vegetation, arthropods, and small mammals were collected for plutonium analysis and mass determination from each of two macroplots. Small aliquots (5 g or less) were analyzed by a rapid liquid scintillation technique and by alpha spectrometry. Of the compartments sampled, greater than 99% of the total plutonium was contained in the soil. The concentrations of plutonium in soil were significantly inversely correlated with distance from the contamination source, depth of the sample, and particle size of the sieved soil samples. The soil data suggested that the distribution of contamination largely resulted from physical transport processes. A mechanism of agglomerated submicron plutonium oxide particles and larger (1-500 μm) host soil particles was proposed. Concentrations of Pu in litter and vegetation were inversely correlated to distance from the source and directly correlated to soil concentrations at the same location. Comparatively high concentration ratios of vegetation to soil suggested wind resuspension of contamination as an important transport mechanism. Arthropod and small mammal samples were highly skewed, kurtotic, and quite variable, having coefficients of variation (standard deviation/mean) as high as 600%. Bone Pu concentrations were lower than other tissues. Hide, GI, and lung were generally not higher in Pu than kidney, liver and muscle

  12. Distinguishing Intensity Levels of Grassland Fertilization Using Vegetation Indices

    OpenAIRE

    Jens L. Hollberg; Jürgen Schellberg

    2017-01-01

    Monitoring the reaction of grassland canopies on fertilizer application is of major importance to enable a well-adjusted management supporting a sustainable production of the grass crop. Up to date, grassland managers estimate the nutrient status and growth dynamics of grasslands by costly and time-consuming field surveys, which only provide low temporal and spatial data density. Grassland mapping using remotely-sensed Vegetation Indices (VIs) has the potential to contribute to solving these ...

  13. Bird communities and biomass yields in potential bioenergy grasslands.

    Directory of Open Access Journals (Sweden)

    Peter J Blank

    Full Text Available Demand for bioenergy is increasing, but the ecological consequences of bioenergy crop production on working lands remain unresolved. Corn is currently a dominant bioenergy crop, but perennial grasslands could produce renewable bioenergy resources and enhance biodiversity. Grassland bird populations have declined in recent decades and may particularly benefit from perennial grasslands grown for bioenergy. We asked how breeding bird community assemblages, vegetation characteristics, and biomass yields varied among three types of potential bioenergy grassland fields (grass monocultures, grass-dominated fields, and forb-dominated fields, and assessed tradeoffs between grassland biomass production and bird habitat. We also compared the bird communities in grassland fields to nearby cornfields. Cornfields had few birds compared to perennial grassland fields. Ten bird Species of Greatest Conservation Need (SGCN were observed in perennial grassland fields. Bird species richness and total bird density increased with forb cover and were greater in forb-dominated fields than grass monocultures. SGCN density declined with increasing vertical vegetation density, indicating that tall, dense grassland fields managed for maximum biomass yield would be of lesser value to imperiled grassland bird species. The proportion of grassland habitat within 1 km of study sites was positively associated with bird species richness and the density of total birds and SGCNs, suggesting that grassland bioenergy fields may be more beneficial for grassland birds if they are established near other grassland parcels. Predicted total bird density peaked below maximum biomass yields and predicted SGCN density was negatively related to biomass yields. Our results indicate that perennial grassland fields could produce bioenergy feedstocks while providing bird habitat. Bioenergy grasslands promote agricultural multifunctionality and conservation of biodiversity in working landscapes.

  14. Soil acidification and liming in grassland production and grassland soil fertility in Slovenia

    Directory of Open Access Journals (Sweden)

    Jure ČOP

    2015-12-01

    Full Text Available This paper reviews the evidences on grassland soil acidity and liming in relation to soil processes and herbage production. There is also an outline of the present state of soil acidity and acidity-related traits – contents of organic matter (OM, phosphorus (P and potassium (K in Slovene grassland. In grassland, soil acidification is an ongoing process under humid climate conditions. It is mainly driven by leaching of nutrients, net loss of cations due to retention in livestock products, use of physiologically acid fertilizers, acid rain and N2 fixation. This process is reduced by strong pH buffering capacity of the soil and by physiologically basic fertilizers. Acid grassland soils in Slovenia are widely distributed in spite of the fact that 44% of the total land has developed from a carbonate parent material. Of the 1713 grassland soil samples analysed during 2005-2007 45% were regarded as acid ones (pH < 5.5; in KCl, 57% as soils with very low P status (˂ 6 mg P2O5/100 g soil and 22% as soils with very low K status (˂ 10 mg K2O/100 soil. Increased content of soil organic matter was identified for alpine pastures (˃ 10 % OM in 44% of samples, mainly as a result of low decomposition rate. Liming of acid grassland soils did not always reflect in a higher herbage yield. The cause for this inefficiency is plant composition of grassland. Thus, many grassland plants with relatively high production potential have adapted to acid soil conditions. To illustrate the inconsistent liming effect three researches are reviewed. In the first two researches liming along with fertilizer application did not increase the yield comparing to the fertilized control while in the third research the increase amounted 26 %. Liming improves considerably botanical composition of the acid grassland (e.g. sward where Common Bent – Agrostis tenuis Sibth. – prevails and thus indirectly affects palatability and nutritive value of herbage. Grassland liming has a weak

  15. Grassland ecology and diversity (Ecologia y diversidad de pastizales)

    Science.gov (United States)

    Laurie B. Abbott

    2006-01-01

    Grasslands of the Chihuahuan Desert region are ecologically and economically important. These grasslands are valued for their rangeland, wildlife, watershed, and recreation resources. Biological diversity also raises the value of grassland communities. The potential for multiple uses within the region increases as the diversity of the resource base increases. In order...

  16. Appreciation of the functions of grasslands by Irish stakeholders

    NARCIS (Netherlands)

    Hennessy, D.; Pol-van Dasselaar, van den A.

    2014-01-01

    The European project MultiSward studied the appreciation of different functions of grasslands by European stakeholders. This paper describes the importance of grasslands for stakeholders in Ireland. Ireland currently has approximately 4.6 million ha of grassland, which is 90% of the total utilized

  17. Predation drives nesting success in moist highland grasslands: the ...

    African Journals Online (AJOL)

    By focusing on process-oriented data rather than inventory-type data, this study provides a robust understanding of the effects of agricultural management on grassland bird reproductive output in the moist highland grasslands (MHGs) of South Africa. Four-hundred and four nests of 12 grassland-breeding bird species were ...

  18. COENOLOGICAL SHIFT FOLLOWING FERTILIZATION IN MEDITERRANEAN GRASSLAND

    Directory of Open Access Journals (Sweden)

    ALESSANDRO SERAFINI SAULI

    2006-05-01

    Full Text Available In Rome both meadows of CentraI-European affinity and Mediterranean dry grasslands are presento We studied a site (Parco Regionale Urbano de] Pineto in Rome with very diverse vegetation, where species belonging to both coenologica] groups oceur. Wc fertilized a grassland with a combination of phosphorus (P and nitrogen (N. After fertilization diagDostie species of Helianthemetea guttati (Thcrophytes dccrease while species of MolinioArrhenatheretea (Hemicriptophytes increase. In a climate as that of Rome, transition between Mediterranean (with summer drought and Central European (without summer drought, nutrients availability modulates the distribution of vegetation Classes with respectively Mediterranean or Central-Europe affinities.

  19. Regional variability of grassland CO2 fluxes in Tyrol/Austria

    Science.gov (United States)

    Irschick, Christoph; Hammerle, Albin; Haslwanter, Alois; Wohlfahrt, Georg

    2010-05-01

    The FLUXNET project [1] aims at quantifying the magnitude and controls on the CO2, H2O and energy exchange of terrestrial ecosystems. Ideally, the various biomes of the Earth would be sampled in proportion to their spatial extent - in reality, however, study site selection is usually based on other (more practical) criteria so that a bias exists towards certain biomes and ecosystem types. This may be problematic because FLUXNET data are used to calibrate/parameterize models at various scales - if certain ecosystems are poorly replicated this may bias model predictions. Here we present data from a project in Tyrol/Austria where we have been investigating the CO2, H2O and energy exchange of five grassland sites during 2005-2007. The five permanent grassland sites were exposed to similar climate, but differed slightly in management. In a FLUXNET style approach, any of these sites might have been selected for making long-term flux measurements - the aim of this project was to examine the representativeness of these sites and, if evident, elucidate the causes for and controls on differences between sites. To this end we conducted continuous eddy covariance flux measurements at one (anchor) site [2, 3], and episodic, month long flux measurements at the four additional sites using a roving eddy covariance tower. These data were complemented by measurements of environmental drivers, the amount of above ground phytomass and basic data on vegetation and soil type, as well as management. Data are subject to a rigorous statistical analysis in order to quantify significant differences in the CO2, H2O and energy exchange between the sites and to identify the factors which are responsible for these differences. In the present contribution we report results on CO2 fluxes. Our major findings are that (i) site-identity of the surveyed grassland ecosystems was a significant factor for the net ecosystem CO2 exchange (NEE), somewhat less for gross primary production (GPP) and not for

  20. Application of a rule-based model to estimate mercury exchange for three background biomes in the continental United States

    Science.gov (United States)

    Hartman, J.S.; Weisberg, P.J.; Pillai, R.; Ericksen, J.A.; Kuiken, T.; Lindberg, S.E.; Zhang, H.; Rytuba, J.J.; Gustin, M.S.

    2009-01-01

    Ecosystems that have low mercury (Hg) concentrations (i.e., not enriched or impactedbygeologic or anthropogenic processes) cover most of the terrestrial surface area of the earth yet their role as a net source or sink for atmospheric Hg is uncertain. Here we use empirical data to develop a rule-based model implemented within a geographic information system framework to estimate the spatial and temporal patterns of Hg flux for semiarid deserts, grasslands, and deciduous forests representing 45% of the continental United States. This exercise provides an indication of whether these ecosystems are a net source or sink for atmospheric Hg as well as a basis for recommendation of data to collect in future field sampling campaigns. Results indicated that soil alone was a small net source of atmospheric Hg and that emitted Hg could be accounted for based on Hg input by wet deposition. When foliar assimilation and wet deposition are added to the area estimate of soil Hg flux these biomes are a sink for atmospheric Hg. ?? 2009 American Chemical Society.

  1. Use of BIOME-BGC to simulate water and carbon fluxes within Mediterranean macchia

    OpenAIRE

    Chiesi M; Chirici G; Corona P; Duce P; Salvati R; Spano D; Vaccari FP; Maselli F

    2012-01-01

    The biogeochemical model BIOME-BGC is capable to estimate the main ecophysiological processes characterising all terrestrial ecosystems. To this aim it needs to be properly adapted to reproduce the behaviour of each biome type through a calibration phase. The aim of this paper is to adapt BIOME-BGC to reproduce the evapotranspiration (ET) and photosynthesis (GPP) of Mediterranean macchia spread all over Italy. Ten different sites were selected in the Centre-South of Italy and their gross prim...

  2. Radioecological sensitivity of permanent grasslands

    International Nuclear Information System (INIS)

    Besson, Benoit

    2009-01-01

    The project 'SENSIB' of the Institute for Radiological Protection and Nuclear Safety (IRSN) aims at characterizing and classifying parameters with significant impact on the transfer of radioactive contaminants in the environment. This thesis is focused on permanent grassland areas. Its objectives are the analysis of the activity variations of two artificial radionuclides ( 137 Cs and 90 Sr) in the chain from soil to dairy products as well as the categorization of ecological and anthropogenic parameters, which determine the sensitivity of the studied area. For this study, in situ sampling is carried out in 15 farms in 3 different French regions (Charente, Puy-de-Dome and Jura). The sampling sites are chosen according to their natural variations (geology, altitude and climate) and the soil types. Additionally to the radiologic measurements, geographic, soil and vegetation data as well as data concerning cattle-rearing and cheese manufacturing processes are gathered. From the soil to the grass vegetation, 137 Cs transfer factors vary between 3 x 10-3 and 148 x 10-3 Bq kg-1 (dry weight) per Bq kg-1 (dry weight) (N = 73). Theses transfer factors are significantly higher in the Puy-de-Dome region than in the Jura region. The 137 Cs transfer factor from cattle feed to milk varies from 5.9 x 10-3 to 258 x 10-3 Bq kg-1 (fresh weight) per Bq kg-1 (dry weight) (N = 28). Statistically, it is higher in the Charente region. Finally, the 90 Sr transfer factor from milk to cheese ranges from 3.9 to 12.1. The studied site with the highest factor is the Jura (N = 25). The link between milk and dairy products is the stage with the most 137 Cs and 90 Sr transfers. A nonlinear approach based on a discretization method of the transfer factor with multiple comparison tests admits a classification of the sensitivity factors from soil to grass vegetation. We can determine 20 factors interfering in the 137 Cs transfer into the vegetation, for instance, the clay rate of the soils or a marker

  3. Sustaining the grassland sea: Regional perspectives on identifying, protecting and restoring the Sky Island region's most intact grassland valley landscapes

    Science.gov (United States)

    Gitanjali S. Bodner; Peter Warren; David Gori; Karla Sartor; Steven Bassett

    2013-01-01

    Grasslands of the Sky Islands region once covered over 13 million acres in southeastern Arizona and adjacent portions of New Mexico, Sonora, and Chihuahua. Attempts to evaluate current ecological conditions suggest that approximately two thirds of these remain as intact or restorable grassland habitat. These grasslands provide watershed services such as flood control...

  4. Evaluating fire danger in Brazilian biomes: present and future patterns

    Science.gov (United States)

    Silva, Patrícia; Bastos, Ana; DaCamara, Carlos; Libonati, Renata

    2017-04-01

    Climate change is expected to have a significant impact on fire occurrence and activity, particularly in Brazil, a region known to be fire-prone [1]. The Brazilian savanna, commonly referred to as cerrado, is a fire-adapted biome covering more than 20% of the country's total area. It presents the highest numbers of fire events, making it particularly susceptible to changes in climate. It is thus essential to understand the present fire regimes in Brazilian biomes, in order to better evaluate future patterns. The CPTEC/INPE, the Brazilian Center for Weather Forecasting and Climate Research at the Brazilian National Institute of Space Research developed a fire danger index based on the occurrence of hundreds of thousands of fire events in the main Brazilian biomes [2]: the Meteorological Fire Danger Index (MFDI). This index indicates the predisposition of vegetation to be burned on a given day, for given climate conditions preceding that day. It relies on daily values of air temperature, relative humidity, accumulated precipitation and vegetation cover. In this study we aim to access the capability of the MFDI to accurately replicate present fire conditions for different biomes, with a special focus on cerrado. To this end, we assess the link between the MFDI as calculated by three different reanalysis (ERA-Interim, NCEP/DOE Reanalysis 2 and MERRA-2) and the observed burned area. We further calculate the validated MFDI using a regional climate model, the RCA4 as forced by EC-Earth from CORDEX, to understand the ability of the model to characterize present fire danger. Finally, the need to calibrate the model to better characterize future fire danger was also evaluated. This work was developed within the framework of the Brazilian Fire-Land-Atmosphere System (BrFLAS) Project financed by the Portuguese and Brazilian science foundations, FCT and FAPESP (project references FAPESP/1389/2014 and 2014/20042-2). [1] KRAWCHUK, M.A.; MORITZ, M.A.; PARISIEN, M.A.; VAN DORN, J

  5. Grasslands feeling the heat: The effects of elevated temperatures on a subtropical grassland

    Directory of Open Access Journals (Sweden)

    Rowan D. Buhrmann

    2016-12-01

    Conclusions: OTCs can simulate realistic increases of air temperature in subtropical grasslands. Graminoids and shrubs appear to benefit from elevated temperatures whilst forbs decrease in abundance, possibly through competition and/or direct physiological effects.

  6. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity.

    Science.gov (United States)

    Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D; Jones, Edward O; Hatano, Ryusuke

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959-2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from -1.26MgCha(-1)yr(-1) in 1959-0.26 Mg Cha(-1)yr(-1) in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959-2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    International Nuclear Information System (INIS)

    Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D.; Jones, Edward O.; Hatano, Ryusuke

    2016-01-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha"−"1 yr"−"1 in 1959–0.26 Mg C ha"−"1 yr"−"1 in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate conditions. • NBP

  8. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xi, E-mail: icy124@hotmail.com [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Toma, Yo [Faculty of Agriculture, Ehime University, 3-5-7, Tarumi, Matsuyama 790-8566, Ehime (Japan); Yeluripati, Jagadeesh [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland (United Kingdom); Iwasaki, Shinya [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Bellingrath-Kimura, Sonoko D. [Leibniz Centre for Agricultural Landscape Research, Institute of Land Use Systems (Germany); Jones, Edward O. [Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London (United Kingdom); Hatano, Ryusuke [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan)

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha{sup −1} yr{sup −1} in 1959–0.26 Mg C ha{sup −1} yr{sup −1} in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate

  9. On the stability of mixed grasslands

    NARCIS (Netherlands)

    Schulte, R.P.O.

    2001-01-01

    Recent years have seen a renewed interest in the use of white clover (Trifolium repens) in grasslands, as a more sustainable alternative to fertiliser nitrogen inputs. However, mixtures of grasses and white clover have frequently been associated with unstable and hence unreliable herbage

  10. Purpose and Need for a Grassland Assessment

    Science.gov (United States)

    Deborah M. Finch; Cathy W. Dahms

    2004-01-01

    This report is volume 1 of an ecological assessment of grassland ecosystems in the Southwestern United States, and it is one of a series of planned publications addressing major ecosystems of the Southwest. The first assessment, General Technical Report RM-GTR- 295, An Assessment of Forest Ecosystem Health in the Southwest (by Dahms and Geils, technical editors,...

  11. [Spatiotemporal characteristics of MODIS NDVI in Hulunber Grassland].

    Science.gov (United States)

    Zhang, Hong-Bin; Yang, Gui-Xia; Wu, Wen-Bin; Li, Gang; Chen, Bao-Rui; Xin, Xiao-Ping

    2009-11-01

    Time-series MODIS NDVI datasets from 2000 to 2008 were used to study the spatial change trend, fluctuation degree, and occurrence time of the annual NDVImax of four typical grassland types, i.e., lowland meadow, temperate steppe, temperate meadow steppe, and upland meadow, in Hulunber Grassland. In 2000-2008, the vegetation in Hulunber Grassland presented an obvious deterioration trend. The mean annual NDVImax of the four grassland types had a great fluctuation, especially in temperate steppe where the maximum change in the mean value of annual NDVImax approximated to 50%. As for the area change of different grade grasslands, the areas with NDVImax between 0.4 and 1 accounted for about 91% of the total grassland area, which suggested the good vegetation coverage in the Grassland. However, though the areas with NDVImax values in (0.4, 0.8) showed an increasing trend, the areas with NDVImax values in (0.2, 0.4) and (0.8, 1) decreased greatly in the study period. Overall, the deteriorating grassland took up about 66.25% of the total area, and the restoring grassland took the rest. There was about 62.85% of the grassland whose NDVImax occurred between the 193rd day and the 225th day in each year, indicating that this period was the most important vegetation growth season in Hulunber Grassland.

  12. Ticks parasitizing bats (Mammalia: Chiroptera) in the Caatinga Biome, Brazil.

    Science.gov (United States)

    Luz, Hermes Ribeiro; Muñoz-Leal, Sebastián; Almeida, Juliana Cardoso de; Faccini, João Luiz Horacio; Labruna, Marcelo Bahia

    2016-01-01

    In this paper, the authors report ticks parasitizing bats from the Serra das Almas Natural Reserve (RPPN) located in the municipality of Crateús, state of Ceará, in the semiarid Caatinga biome of northeastern Brazil. The study was carried out during nine nights in the dry season (July 2012) and 10 nights in the rainy season (February 2013). Only bats of the Phyllostomidae and Mormoopidae families were parasitized by ticks. The species Artibeus planirostris and Carolia perspicillata were the most parasitized. A total of 409 larvae were collected and classified into three genera: Antricola (n = 1), Nothoaspis (n = 1) and Ornithodoros (n = 407). Four species were morphologically identified as Nothoaspis amazoniensis, Ornithodoros cavernicolous, Ornithodoros fonsecai, Ornithodoros hasei, and Ornithodoros marinkellei. Ornithodoros hasei was the most common tick associated with bats in the current study. The present study expand the distributional ranges of at least three soft ticks into the Caatinga biome, and highlight an unexpected richness of argasid ticks inhabiting this arid ecosystem.

  13. Ticks parasitizing bats (Mammalia: Chiroptera in the Caatinga Biome, Brazil

    Directory of Open Access Journals (Sweden)

    Hermes Ribeiro Luz

    Full Text Available Abstract In this paper, the authors report ticks parasitizing bats from the Serra das Almas Natural Reserve (RPPN located in the municipality of Crateús, state of Ceará, in the semiarid Caatinga biome of northeastern Brazil. The study was carried out during nine nights in the dry season (July 2012 and 10 nights in the rainy season (February 2013. Only bats of the Phyllostomidae and Mormoopidae families were parasitized by ticks. The species Artibeus planirostris and Carolia perspicillata were the most parasitized. A total of 409 larvae were collected and classified into three genera: Antricola (n = 1, Nothoaspis (n = 1 and Ornithodoros (n = 407. Four species were morphologically identified as Nothoaspis amazoniensis, Ornithodoros cavernicolous, Ornithodoros fonsecai, Ornithodoros hasei, and Ornithodoros marinkellei. Ornithodoros hasei was the most common tick associated with bats in the current study. The present study expand the distributional ranges of at least three soft ticks into the Caatinga biome, and highlight an unexpected richness of argasid ticks inhabiting this arid ecosystem.

  14. biojs-io-biom, a BioJS component for handling data in Biological Observation Matrix (BIOM format [version 2; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Markus J. Ankenbrand

    2017-01-01

    Full Text Available The Biological Observation Matrix (BIOM format is widely used to store data from high-throughput studies. It aims at increasing interoperability of bioinformatic tools that process this data. However, due to multiple versions and implementation details, working with this format can be tricky. Currently, libraries in Python, R and Perl are available, whilst such for JavaScript are lacking. Here, we present a BioJS component for parsing BIOM data in all format versions. It supports import, modification, and export via a unified interface. This module aims to facilitate the development of web applications that use BIOM data. Finally, we demonstrate its usefulness by two applications that already use this component. Availability: https://github.com/molbiodiv/biojs-io-biom, https://dx.doi.org/10.5281/zenodo.218277

  15. [Temporal and spatial heterogeneity analysis of optimal value of sensitive parameters in ecological process model: The BIOME-BGC model as an example.

    Science.gov (United States)

    Li, Yi Zhe; Zhang, Ting Long; Liu, Qiu Yu; Li, Ying

    2018-01-01

    The ecological process models are powerful tools for studying terrestrial ecosystem water and carbon cycle at present. However, there are many parameters for these models, and weather the reasonable values of these parameters were taken, have important impact on the models simulation results. In the past, the sensitivity and the optimization of model parameters were analyzed and discussed in many researches. But the temporal and spatial heterogeneity of the optimal parameters is less concerned. In this paper, the BIOME-BGC model was used as an example. In the evergreen broad-leaved forest, deciduous broad-leaved forest and C3 grassland, the sensitive parameters of the model were selected by constructing the sensitivity judgment index with two experimental sites selected under each vegetation type. The objective function was constructed by using the simulated annealing algorithm combined with the flux data to obtain the monthly optimal values of the sensitive parameters at each site. Then we constructed the temporal heterogeneity judgment index, the spatial heterogeneity judgment index and the temporal and spatial heterogeneity judgment index to quantitatively analyze the temporal and spatial heterogeneity of the optimal values of the model sensitive parameters. The results showed that the sensitivity of BIOME-BGC model parameters was different under different vegetation types, but the selected sensitive parameters were mostly consistent. The optimal values of the sensitive parameters of BIOME-BGC model mostly presented time-space heterogeneity to different degrees which varied with vegetation types. The sensitive parameters related to vegetation physiology and ecology had relatively little temporal and spatial heterogeneity while those related to environment and phenology had generally larger temporal and spatial heterogeneity. In addition, the temporal heterogeneity of the optimal values of the model sensitive parameters showed a significant linear correlation

  16. Pollen-based biome reconstruction for southern Europe and Africa 18,000 yr BP

    NARCIS (Netherlands)

    Elenga, H; Peyron, O; Bonnefille, R; Jolly, D; Cheddadi, R; Guiot, J; Andrieu, [No Value; Bottema, S; Buchet, G; de Beaulieu, JL; Hamilton, AC; Maley, J; Marchant, R; Perez-Obiol, R; Reille, M; Riollet, G; Scott, L; Straka, H; Taylor, D; Van Campo, E; Vincens, A; Laarif, F; Jonson, H

    Pollen data from 18,000 C-14 yr sp were compiled in order to reconstruct biome distributions at the last glacial maximum in southern Europe and Africa. Biome reconstructions were made using the objective biomization method applied to pollen counts using a complete list of dryland taxa wherever

  17. Factors affecting ammonium uptake in streams - an inter-biome perspective

    Science.gov (United States)

    Jackson R Webster; Partick J. Mulholland; Jennifer L. Tanks; H. Maurice Valett; Walter K. Dodds; Bruce J. Peterson; William B. Bowden; Clifford N. Dahm; Stuart Findlay; Stanley V. Gregory; Nancy B. Grimm; Stephen K. Hamilton; Sherri L. Johnson; Eugenia Marti; William H. McDowell; Judy L. Meyer; Donna D. Morrall; Steven A. Thomas; Wilfred M. Wollhem

    2003-01-01

    1. The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and...

  18. Increasing atmospheric CO2 overrides the historical legacy of multiple stable biome states in Africa.

    Science.gov (United States)

    Moncrieff, Glenn R; Scheiter, Simon; Bond, William J; Higgins, Steven I

    2014-02-01

    The dominant vegetation over much of the global land surface is not predetermined by contemporary climate, but also influenced by past environmental conditions. This confounds attempts to predict current and future biome distributions, because even a perfect model would project multiple possible biomes without knowledge of the historical vegetation state. Here we compare the distribution of tree- and grass-dominated biomes across Africa simulated using a dynamic global vegetation model (DGVM). We explicitly evaluate where and under what conditions multiple stable biome states are possible for current and projected future climates. Our simulation results show that multiple stable biomes states are possible for vast areas of tropical and subtropical Africa under current conditions. Widespread loss of the potential for multiple stable biomes states is projected in the 21st Century, driven by increasing atmospheric CO2 . Many sites where currently both tree-dominated and grass-dominated biomes are possible become deterministically tree-dominated. Regions with multiple stable biome states are widespread and require consideration when attempting to predict future vegetation changes. Testing for behaviour characteristic of systems with multiple stable equilibria, such as hysteresis and dependence on historical conditions, and the resulting uncertainty in simulated vegetation, will lead to improved projections of global change impacts. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. S2Biom database with logistical components of the biomass value chain

    NARCIS (Netherlands)

    Annevelink, E.; Groot, de H.L.E.; Shah, N.; Giarola, S.; Pantaleo, M.; Anttila, P.; Vis, Martijn; Raa, te Rik; Berg, van den Douwe; Gabrielle, B.

    2015-01-01

    The S2Biom project (www.s2biom.eu) - Delivery of sustainable supply of non-food biomass to support
    a resource-efficient Bioeconomy in Europe - supports sustainable delivery chains of non-food biomass feedstock.
    This poses a logistical challenge because the quality and handling

  20. Mid- to Late-Holocene pollen-based biome reconstructions for Colombia

    NARCIS (Netherlands)

    Marchant, R.; Behling, H.; Berrío, J.C.; Cleef, A.M.; Duivenvoorden, J.; Hooghiemstra, H.; Kuhry, P.; Melief, B.; Geel, van B.; Hammen, van der T.; Reenen, van T.; Wille, M.

    2001-01-01

    The assignment of Colombian pollen data to biomes allows the data to be synthesised at 10 `time windows' from the present-day to 6000 radiocarbon years before present (BP). The modern reconstructed biomes are compared to a map of modern potential vegetation to check the applicability of the method

  1. Climate and litter quality differently modulate the effects of soil fauna on litter decomposition across biomes.

    Science.gov (United States)

    García-Palacios, Pablo; Maestre, Fernando T; Kattge, Jens; Wall, Diana H

    2013-08-01

    Climate and litter quality have been identified as major drivers of litter decomposition at large spatial scales. However, the role played by soil fauna remains largely unknown, despite its importance for litter fragmentation and microbial activity. We synthesised litterbag studies to quantify the effect sizes of soil fauna on litter decomposition rates at the global and biome scales, and to assess how climate, litter quality and soil fauna interact to determine such rates. Soil fauna consistently enhanced litter decomposition at both global and biome scales (average increment ~ 37%). [corrected]. However, climate and litter quality differently modulated the effects of soil fauna on decomposition rates between biomes, from climate-driven biomes to those where climate effects were mediated by changes in litter quality. Our results advocate for the inclusion of biome-specific soil fauna effects on litter decomposition as a mean to reduce the unexplained variation in large-scale decomposition models. © 2013 John Wiley & Sons Ltd/CNRS.

  2. Biogeography of photoautotrophs in the high polar biome

    Directory of Open Access Journals (Sweden)

    Stephen Brian Pointing

    2015-09-01

    Full Text Available The global latitudinal gradient in biodiversity weakens in the high polar biome and so an alternative explanation for distribution of Arctic and Antarctic photoautotrophs is required. Here we identify how temporal, microclimate and evolutionary drivers of biogeography are important, rather than the macroclimate features that drive plant diversity patterns elsewhere. High polar ecosystems are biologically unique, with a more central role for bryophytes, lichens and microbial photoautotrophs over that of vascular plants. Constraints on vascular plants arise mainly due to stature and ontogenetic barriers. Conversely non-vascular plant and microbial photoautotroph distribution is correlated with favourable microclimates and the capacity for poikilohydric dormancy. Contemporary distribution also depends on evolutionary history, with adaptive and dispersal traits as well as legacy influencing biogeography. We highlight the relevance of these findings to predicting future impacts on polar plant diversity and to the current status of plants in Arctic and Antarctic conservation policy frameworks.

  3. Climate sensitivity of shrub growth across the tundra biome

    DEFF Research Database (Denmark)

    Myers-Smith, Isla H.; Elmendorf, Sarah C.; Beck, Pieter S.A.

    2015-01-01

    Rapid climate warming in the tundra biome has been linked to increasing shrub dominance1–4. Shrub expansion can modify climate by altering surface albedo, energy and water balance, and permafrost2,5–8, yet the drivers of shrub growth remain poorly understood. Dendroecological data consisting...... of multi-decadal time series of annual shrub growth provide an underused resource to explore climate–growth relationships. Here, we analyse circumpolar data from 37 Arctic and alpine sites in 9 countries, including 25 species, and 42,000 annual growth records from 1,821 individuals. Our analyses...... demonstrate that the sensitivity of shrub growth to climate was: (1) heterogeneous, with European sites showing greater summer temperature sensitivity than North American sites, and (2) higher at sites with greater soil moisture and for taller shrubs (for example, alders and willows) growing at their northern...

  4. Seed longevity of Eragrostis plana Nees buried in natural grassland soil

    Directory of Open Access Journals (Sweden)

    Renato Borges de Medeiros

    2014-11-01

    Full Text Available The objective of this research was to evaluate the seed longevity of Eragrostis plana Nees buried at different soil depths, in a natural-grassland area in the Pampa biome (46 m altitude, 30º05´S and 51º40´W of Rio Grande do Sul State, Brazil. The experimental design was a split-plot type in complete blocks with two factors: seeds buried at five different depth levels (soil surface and 2.5, 5, 10 and 20 cm and seven exhumation dates. The blocks were allocated in natural grassland grazed by cattle, allocated in a 12-m-long transection. Fifty-four permeable nylon bags filled with 100 seeds in each division, with five vertical divisions, were buried in each row. Seven exhumation dates were used: the first on October 14, 2003 and the last on January 14, 2006. The percentage of viable seeds of E. plana, collected at seven exhumation times and set at different depths in the soil horizon, were described by simple negative exponential equations. Based on the model, the percentage of viable seeds collected at the five depths, (soil surface and 2.5, 5, 10, and 20 cm, after 2.5 years of burial, were 0.1, 0.5, 1.0, 7.4 and 22.1%, respectively. Increase in depth is directly associated with physical and physiological seed integrity of E. plana. Negative simple exponential equations can be used to predict seed longevity of E. plana buried in nylon bags. This invader species accumulates soil seed-bank of high longevity.

  5. Grassland communities of urban open spaces in Bloemfontein, Free State, South Africa

    Directory of Open Access Journals (Sweden)

    Mamokete N.V. Dingaan

    2013-02-01

    Full Text Available Natural vegetation in urban environments is greatly impacted by human activities and it is in constant threat of degradation and destruction as a result of urbanisation. This vegetation, although fragmented, serves an important ecological function and needs to be properly managed and conserved. Studies on urban vegetation are lacking in South Africa, with only a handful having been carried out since the end of the last century. This study was initiated to identify, classify and describe the grassland communities of the urban open spaces in Bloemfontein. Relevés were compiled in 61 sample plots, where species present and habitat information were recorded. Care was taken to restrict sample plots to vegetation in pristine condition, wherever possible, and severely degraded stands were avoided. A two-way indicator species analysis (TWINSPAN classification, refined by Braun-Blanquet procedures, revealed two distinct major communities, seven communities and four sub-communities. Both detrended and canonical correspondence analyses indicated the vegetation units to be associated with soil texture and pH, although biotic factors such as overgrazing, burning and mowing also influence the composition of the vegetation. The proper management and conservation of urban open spaces requires in-depth knowledge of the spatial distribution, floristic, structural and functional compositions within the major vegetation types in this environment. The present study further contributed towards formulating ways for the proper management, utilisation and functioning of the open spaces within the Bloemfontein area.Conservation implications: The Grassland Biome of South Africa is poorly conserved, mainly because of its status as an agricultural hub of the country. The preservation of natural and semi-natural forms of urban vegetation is important because such vegetation, although often disturbed and degraded, could form dispersal corridors between peri-urban and rural

  6. Comparative patterns of plant invasions in the Mediterranean biome.

    Science.gov (United States)

    Arianoutsou, Margarita; Delipetrou, Pinelopi; Vilà, Montserrat; Dimitrakopoulos, Panayiotis G; Celesti-Grapow, Laura; Wardell-Johnson, Grant; Henderson, Lesley; Fuentes, Nicol; Ugarte-Mendes, Eduardo; Rundel, Philip W

    2013-01-01

    The objective of this work was to compare and contrast the patterns of alien plant invasions in the world's five mediterranean-climate regions (MCRs). We expected landscape age and disturbance history to have bearing on levels of invasion. We assembled a database on naturalized alien plant taxa occurring in natural and semi-natural terrestrial habitats of all five regions (specifically Spain, Italy, Greece and Cyprus from the Mediterranean Basin, California, central Chile, the Cape Region of South Africa and Southwestern - SW Australia). We used multivariate (hierarchical clustering and NMDS ordination) trait and habitat analysis to compare characteristics of regions, taxa and habitats across the mediterranean biome. Our database included 1627 naturalized species with an overall low taxonomic similarity among the five MCRs. Herbaceous perennials were the most frequent taxa, with SW Australia exhibiting both the highest numbers of naturalized species and the highest taxonomic similarity (homogenization) among habitats, and the Mediterranean Basin the lowest. Low stress and highly disturbed habitats had the highest frequency of invasion and homogenization in all regions, and high natural stress habitats the lowest, while taxonomic similarity was higher among different habitats in each region than among regions. Our analysis is the first to describe patterns of species characteristics and habitat vulnerability for a single biome. We have shown that a broad niche (i.e. more than one habitat) is typical of naturalized plant species, regardless of their geographical area of origin, leading to potential for high homogenization within each region. Habitats of the Mediterranean Basin are apparently the most resistant to plant invasion, possibly because their landscapes are generally of relatively recent origin, but with a more gradual exposure to human intervention over a longer period.

  7. Improved simulation of poorly drained forests using Biome-BGC.

    Science.gov (United States)

    Bond-Lamberty, Ben; Gower, Stith T; Ahl, Douglas E

    2007-05-01

    Forested wetlands and peatlands are important in boreal and terrestrial biogeochemical cycling, but most general-purpose forest process models are designed and parameterized for upland systems. We describe changes made to Biome-BGC, an ecophysiological process model, that improve its ability to simulate poorly drained forests. Model changes allowed for: (1) lateral water inflow from a surrounding watershed, and variable surface and subsurface drainage; (2) adverse effects of anoxic soil on decomposition and nutrient mineralization; (3) closure of leaf stomata in flooded soils; and (4) growth of nonvascular plants (i.e., bryophytes). Bryophytes were treated as ectohydric broadleaf evergreen plants with zero stomatal conductance, whose cuticular conductance to CO(2) was dependent on plant water content. Individual model changes were parameterized with published data, and ecosystem-level model performance was assessed by comparing simulated output to field data from the northern BOREAS site in Manitoba, Canada. The simulation of the poorly drained forest model exhibited reduced decomposition and vascular plant growth (-90%) compared with that of the well-drained forest model; the integrated bryophyte photosynthetic response accorded well with published data. Simulated net primary production, biomass and soil carbon accumulation broadly agreed with field measurements, although simulated net primary production was higher than observed data in well-drained stands. Simulated net primary production in the poorly drained forest was most sensitive to oxygen restriction on soil processes, and secondarily to stomatal closure in flooded conditions. The modified Biome-BGC remains unable to simulate true wetlands that are subject to prolonged flooding, because it does not track organic soil formation, water table changes, soil redox potential or anaerobic processes.

  8. Monitoring Effect of Fire on Ant Assemblages in Brazilian Rupestrian Grasslands: Contrasting Effects on Ground and Arboreal Fauna

    Directory of Open Access Journals (Sweden)

    Diego Anjos

    2017-06-01

    Full Text Available Fire is one of the most relevant ecological disturbances in nature. Little is known about the effects of fire on biodiversity in ecosystems like rupestrian grasslands, which share characteristics with savanna and forest biomes. Brazilian rupestrian grasslands are part of an endangered ecosystem that has been modified by anthropogenic fire events that have become more intense in recent decades. In this study, we evaluated the effects of fire on ground and arboreal ant assemblages through a two-year monitoring program (24 monthly samplings. We found that fire does not change cumulative species richness after 24 months, and that fire does not affect mean ant richness, abundance, and species composition in arboreal ants. On the other hand, fire increased mean ground ant species richness and abundance, and caused a significant change in species composition. Our results indicate a weak and beneficial effect of fire only for ground ant communities, which generally agrees with results from other studies in Brazilian savannas. Taken together, results from these studies may be useful for improvement of fire suppression policy in fire-prone habitats in Brazil.

  9. Two New Species and New Occurrences of Syneches Walker for Brazilian Biome of Caatinga (Diptera: Hybotidae: Hybotinae).

    Science.gov (United States)

    Soares, M M M; Ale-Rocha, R

    2018-03-13

    Syneches from Brazilian biome of Caatinga were studied, two new species are described, Syneches atratus sp. nov. and Syneches limeirai sp. nov., and three species, Syneches annulipes Bezzi, 1909, Syneches moraballi Smith, 1963, and Syneches rafaeli Ale-Rocha & Vieira, 2008, are recorded for the biome. An identification key for the species of Syneches from Caatinga biome is provided.

  10. Energy analysis of various grassland utilisation systems

    Directory of Open Access Journals (Sweden)

    Jozef Ržonca

    2005-01-01

    Full Text Available In 2003 and 2004 was carried out the energy analysis of the different types of permanent grassland utilization on the Hrubý Jeseník locality. There were estimated values of the particular entrances of additional energy. Energy entrances moved according to the pratotechnologies from 2.17 GJ. ha–1 to 22.70 GJ.ha–1. The biggest share on energy entrances had fertilizers. It was 84.93% by the nitrogen fertilisation. The most energy benefit of brutto and nettoenergy was marked by the low intensive utilisation (33.40 GJ.ha–1 NEL and 32.40 GJ.ha–1 NEV on average. The highest value of energy efficiency (13.23% was marked by the low intensive utilization of permanent grassland. By using of higher doses of industrial fertilizers has energy efficiency decreased. From view of energy benefit and intensiveness on energy entrances it appears the most available utilisation of permanent grassland with three cuts per year (first cut on May 31st at the latest, every next after 60 days or two cuts per year (first cut on July 15th, next cuts after 90 days.

  11. Calibration des fonctions de transfert entre assemblages phytolithiques, structure des végétations et variables bioclimatiques actuelles, pour l'intégration de la dynamique des biomes herbacés dans les modèles de végétation

    OpenAIRE

    Bremond, Laurent

    2003-01-01

    Mme A. Alexandre C. R., CNRS, Aix-en-Provence Co-Directeur de Thèse M. G. Fredlund Pr., University of Wisconsin, Milwaukee Rapporteur M. J. Guiot D. R., CNRS, Aix-en-Provence Directeur de Thèse Mme A-M. Lézine D. R., CNRS, Gif-sur-Yvette Examinateur Mme N. de Noblet Dr. CEA, Gif-sur-Yvette Examinateur M. B. Riéra C. R., CNRS, MNHM, Paris 6 Rapporteur; Grassland biomes are currently dominating the inter-tropical zone, but main proxies used do not reflect properly their range. Therefore, modeli...

  12. The influence of fire on the assemblage structure of foraging birds in grasslands of the Serra da Canastra National Park, Brazil

    Directory of Open Access Journals (Sweden)

    Matheus G. Reis

    2016-06-01

    Full Text Available Grasslands are the most threatened physiognomies of the Cerrado biome (Brazilian savanna, a biodiversity hotspot with conservation as a priority. The Serra da Canastra National Park protects the most important remnants of the Cerrado's southern grasslands, which are under strong anthropogenic pressure. The present study describes the structure of bird assemblages that directly use food resources in burned areas, comparing areas affected by natural fire to the areas where controlled fires were set (a management strategy to combat arson. The tested null hypothesis was that different bird assemblages are structured in a similar manner, regardless of the post-fire period or assessed area. Between December/2012 and January/2015, 92 species were recorded foraging in the study areas. The results indicate that both types of burnings triggered profound and immediate changes in bird assemblages, increasing the number of species and individuals. Natural fires exhibited a more significant influence on the structure (diversity and dominance than prescribed burnings. Nevertheless, all the differences were no longer noticeable after a relatively short time interval of 2-3 months after prescribed burnings and 3-4 after natural fires. The findings may help the understanding of prescribed burnings as a management strategy for bird conservation in grasslands.

  13. SOWING GRASSLANDS – EFFICIENT SOLUTION FOR ZOOTEHNICAL PRODUCTION

    Directory of Open Access Journals (Sweden)

    VALENTINA OFELIA ROBESCU

    2008-05-01

    Full Text Available Recruitment is critical for the maintenance of plant populations and community diversity, but sexual regeneration is considered to be infrequent in climatically harsh habitats such as sub alpine grasslands. For this reasons it is very important to improve the grassland. In this paper we study the interaction among milk production, fertilizations and flower composition in sub alpine grasslands. The agrochemical indicators are important because they influence the pasture value and at the final the milk production.

  14. Effects of grassland management on the emission of methane from grassland on peat soils

    Energy Technology Data Exchange (ETDEWEB)

    Oenema, O. [Department of Soil Science and Plant Nutrition, Wageningen Agricultural University, Wageningen (Netherlands)

    1995-12-31

    The aim of the project on the title subject is to provide insight into the major controlling factors that contribute to the net exchange rates of methane (CH4) between grassland and atmosphere, and to provide quantitative net CH4 emission rates. Net CH4 emissions have been monitored with vented closed flux chambers on both intensively managed grasslands and grasslands in a nature preserve on peat soil in the Netherlands. Net CH4 emissions from intensively managed grasslands (Zegveld, Netherlands) were low in the period January-December 1994, in general in the range of -0.2 to 0.2 mg CH4 m{sup -2} d{sup -1}. Only in the relatively warm summer of 1994, consumption of atmospheric CH4 of about 0.4 mg m{sup -2} d{sup -1} was measured. Effects of ground water level in the range of 30-60 cm below surface were very small. There were also no clear effects of nitrogen fertilization and grazing versus mowing on CH4 emission from the soil. Net CH4 emissions from three extensively managed grasslands in a nature preserve (Nieuwkoopse Plassen area in the Netherlands) ranged from 0-215 mg CH4 m{sup -2} d{sup -1} in the period January 1994-June 1995. Differences between the three sites were quite large, as were the spatial variations at each of the sites. The results presented here indicate that a shift of intensively managed peat grasslands into more natural ecosystems will significantly increase the contribution of Dutch peat soils to the total CH4 emission. refs.

  15. A new distribution range of Ateles chamek (Humboldt 1812) in an ecotone of three biomes in the Paraguay River Basin.

    Science.gov (United States)

    Dos Santos-Filho, Manoel; Bernardo, Christine Steiner São; Van der Laan Barbosa, Henry Willian; Gusmão, Almério Câmara; Jerusalinsky, Leandro; Canale, Gustavo Rodrigues

    2017-07-01

    Historical records of Ateles chamek (black-faced black spider monkey) suggest that the species range extends further south of the known species distribution, within an ecotonal region between the Amazonia, Cerrado and Pantanal biomes in Brazil. Ecotones are zones of habitat transition with high species richness that remain undersampled as conservationists often prioritize biodiversity hotspots. Thus, distribution ranges may be inaccurately measured when species occur in ecotonal zones. We report the first precise records of A. chamek in 24 new localities surveyed in the ecotonal zone of the Upper Paraguay River Basin, and we present subgroup encounter rates in the 11 largest patches (>70 ha) along 207 km of the line transects surveyed. The new records represent an expansion of the distribution of A. chamek approximately 200 km to the south, increasing the known extent of its occurrence by 10.8%. Local tributaries may not be barriers for spider monkeys, which are able to swim and cross slow-moving rivers. However, the dry forests of the Cerrado and the flooded areas of the Pantanal, formed by grassland and scarce trees, may be habitat barriers for A. chamek. The populations living in this ecotonal zone are relatively abundant (1.1-6.67 subgroup sightings/10 km) compared to the heavily hunted continuous forests of northern Amazonia. Furthermore, these values are similar to those for other Ateles spp. inhabiting forests with low or no hunting pressure. We highlight the need for specific conservation action to protect the spider monkeys living in these landscapes, which are threatened by agriculture expansion.

  16. C4 Photosynthesis Promoted Species Diversification during the Miocene Grassland Expansion

    Science.gov (United States)

    Spriggs, Elizabeth L.; Christin, Pascal-Antoine; Edwards, Erika J.

    2014-01-01

    Identifying how organismal attributes and environmental change affect lineage diversification is essential to our understanding of biodiversity. With the largest phylogeny yet compiled for grasses, we present an example of a key physiological innovation that promoted high diversification rates. C4 photosynthesis, a complex suite of traits that improves photosynthetic efficiency under conditions of drought, high temperatures, and low atmospheric CO2, has evolved repeatedly in one lineage of grasses and was consistently associated with elevated diversification rates. In most cases there was a significant lag time between the origin of the pathway and subsequent radiations, suggesting that the ‘C4 effect’ is complex and derives from the interplay of the C4 syndrome with other factors. We also identified comparable radiations occurring during the same time period in C3 Pooid grasses, a diverse, cold-adapted grassland lineage that has never evolved C4 photosynthesis. The mid to late Miocene was an especially important period of both C3 and C4 grass diversification, coincident with the global development of extensive, open biomes in both warm and cool climates. As is likely true for most “key innovations”, the C4 effect is context dependent and only relevant within a particular organismal background and when particular ecological opportunities became available. PMID:24835188

  17. La filatelia biomédica Biomedicine philately

    Directory of Open Access Journals (Sweden)

    Emilio J.A. Roldán

    2011-02-01

    Full Text Available La temática biomédica es un capítulo extendido de la filatelia o coleccionismo de sellos postales. Inaugura la temática la imagen de la diosa Hygeia, en un sello de la isla Nevis de 1861. Los primeros médicos retratados en una estampilla son tres constitucionalistas americanos, en un ejemplar de 1869, pero recién en 1937 aparecen médicos holandeses en reconocimiento específico de sus aportes a la salud. En la Argentina la primera estampilla que oficialmente se ocupa del tema es de 1944, en ayuda de las víctimas del terremoto de San Juan. Florentino Ameghino es el primer científico incluido en 1954, y en 1967 se edita un sello conmemorativo de la Dra. Cecilia Grierson. La filatelia argentina luego reconoce varios de nuestros científicos y médicos, congresos, universidades, campañas sanitarias, temas de odontología, farmacia, enfermería y otros, generando un amplio material filatélico en reconocimiento del valor social que la ciencia biomédica argentina ha logrado en el contexto propio e internacional. Posiblemente sea un científico, el Dr. Bernardo Houssay, uno de los argentinos más veces editado en distintos sellos postales de la filatelia mundial.Biomedicine is a vast field in philately or stamp collecting. It opens the topic the image of the goddess Hygeia, issued in a stamp from Nevis Island dated 1861. The first physicians to appear printed in stamps, in 1869, were three American constitutionalists, but only in 1937 there appear Dutch physicians as an acknowledgement of their contribution to public health. In Argentina the first stamp officially related to the topic was issued in 1944, to raise funds for the victims of the San Juan earthquake. Florentino Ameghino was the first scientist included in 1954, and in 1967 a stamp was issued in honour of Dr. Cecilia Grierson. Afterwards, Argentinean philately has recognized several of our scientists and physicians, congresses, universities, health campaigns, dentistry topics

  18. Distinguishing Intensity Levels of Grassland Fertilization Using Vegetation Indices

    Directory of Open Access Journals (Sweden)

    Jens L. Hollberg

    2017-01-01

    Full Text Available Monitoring the reaction of grassland canopies on fertilizer application is of major importance to enable a well-adjusted management supporting a sustainable production of the grass crop. Up to date, grassland managers estimate the nutrient status and growth dynamics of grasslands by costly and time-consuming field surveys, which only provide low temporal and spatial data density. Grassland mapping using remotely-sensed Vegetation Indices (VIs has the potential to contribute to solving these problems. In this study, we explored the potential of VIs for distinguishing five differently-fertilized grassland communities. Therefore, we collected spectral signatures of these communities in a long-term fertilization experiment (since 1941 in Germany throughout the growing seasons 2012–2014. Fifteen VIs were calculated and their seasonal developments investigated. Welch tests revealed that the accuracy of VIs for distinguishing these grassland communities varies throughout the growing season. Thus, the selection of the most promising single VI for grassland mapping was dependent on the date of the spectra acquisition. A random forests classification using all calculated VIs reduced variations in classification accuracy within the growing season and provided a higher overall precision of classification. Thus, we recommend a careful selection of VIs for grassland mapping or the utilization of temporally-stable methods, i.e., including a set of VIs in the random forests algorithm.

  19. Cattle slurry on grassland - application methods and nitrogen use efficiency

    NARCIS (Netherlands)

    Lalor, S.T.J.

    2014-01-01

    Cattle slurry represents a significant resource on grassland-based farming systems. The objective of this thesis was to investigate and devise cattle slurry application methods and strategies that can be implemented on grassland farms to improve the efficiency with which nitrogen (N) in

  20. Ecological transition in Arizona's subalpine and montane grasslands

    Science.gov (United States)

    Michael R. White

    2000-01-01

    Important components of Southwest forest ecosystem are subalpine and montane grassland communities, Grassland communities provide habitat diversity for wildlife, forage for domestic livestock and wildlife, and contribute to the visual quality of an area. The objectives of this research were to determine if: 1) vegetation attributes and soil-surface cover variables of...

  1. Influence of density on the seasonal utilization of broad grassland ...

    African Journals Online (AJOL)

    We monitored seasonal use of grassland types by white rhinos at two sites within the Hluhluwe iMfolozi Park (HiP). Thirty-two rhinos were removed from one site to reduce rhino density. Seasonal use of grassland types was similar at both sites, but differed to what a previous study reported. This was likely due to higher food ...

  2. Simulating economics and environmental impacts of beef and soybean systems in Brazil's Pamas and Amozon Biomes

    Science.gov (United States)

    Recent reductions in the deforestation of the Amazon biome have highlighted the need for the sustainable intensification of beef and commodity crop production in Brazil to increase agricultural productivity without accelerating adverse environmental impacts related to greenhouse gas emissions, eutro...

  3. Biome-BGC: Modeling Effects of Disturbance and Climate (Thornton et al. 2002)

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This archived model product contains the directions, executables, and procedures for running Biome-BGC, Version 4.1.1, to recreate the results of the...

  4. BIOME: A scientific data archive search-and-order system using browser-aware, dynamic pages

    Science.gov (United States)

    Jennings, S. V.; Yow, T. G.; Ng, V. W.

    1997-01-01

    The Oak Ridge National Laboratory's (ORNL) Distributed Active Archive Center (DAAC) is a data archive and distribution center for the National Air and Space Administration's (NASA) Earth Observing System Data and Information System (EOSDIS). Both the Earth Observing System (EOS) and EOSDIS are components of NASA's contribution to the US Global Change Research Program through its Mission to Planet Earth Program. The ORNL DAAC provides access to data used in ecological and environmental research such as global change, global warming, and terrestrial ecology. Because of its large and diverse data holdings, the challenge for the ORNL DAAC is to help users find data of interest from the hundreds of thousands of files available at the DAAC without overwhelming them. Therefore, the ORNL DAAC has developed the Biogeochemical Information Ordering Management Environment (BIOME), a customized search and order system for the World Wide Web (WWW). BIOME is a public system located at http://www-eosdis. ornl.gov/BIOME/biome.html.

  5. Biome-BGC: Modeling Carbon Dynamics in Ponderosa Pine Stands (Law et al. 2003)

    Data.gov (United States)

    National Aeronautics and Space Administration — This archived model product contains the directions, executables, and procedures for running Biome-BGC, Version 4.1.2, to recreate the results of the following...

  6. Biome-BGC: Terrestrial Ecosystem Process Model, Version 4.1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Biome-BGC is a computer program that estimates fluxes and storage of energy, water, carbon, and nitrogen for the vegetation and soil components of...

  7. Biome-BGC: Terrestrial Ecosystem Process Model, Version 4.1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — Biome-BGC is a computer program that estimates fluxes and storage of energy, water, carbon, and nitrogen for the vegetation and soil components of terrestrial...

  8. BIOME: An Ecosystem Remote Sensor Based on Imaging Interferometry

    Science.gov (United States)

    Peterson, David L.; Hammer, Philip; Smith, William H.; Lawless, James G. (Technical Monitor)

    1994-01-01

    Until recent times, optical remote sensing of ecosystem properties from space has been limited to broad band multispectral scanners such as Landsat and AVHRR. While these sensor data can be used to derive important information about ecosystem parameters, they are very limited for measuring key biogeochemical cycling parameters such as the chemical content of plant canopies. Such parameters, for example the lignin and nitrogen contents, are potentially amenable to measurements by very high spectral resolution instruments using a spectroscopic approach. Airborne sensors based on grating imaging spectrometers gave the first promise of such potential but the recent decision not to deploy the space version has left the community without many alternatives. In the past few years, advancements in high performance deep well digital sensor arrays coupled with a patented design for a two-beam interferometer has produced an entirely new design for acquiring imaging spectroscopic data at the signal to noise levels necessary for quantitatively estimating chemical composition (1000:1 at 2 microns). This design has been assembled as a laboratory instrument and the principles demonstrated for acquiring remote scenes. An airborne instrument is in production and spaceborne sensors being proposed. The instrument is extremely promising because of its low cost, lower power requirements, very low weight, simplicity (no moving parts), and high performance. For these reasons, we have called it the first instrument optimized for ecosystem studies as part of a Biological Imaging and Observation Mission to Earth (BIOME).

  9. Climate control of terrestrial carbon exchange across biomes and continents

    Energy Technology Data Exchange (ETDEWEB)

    Yi Chuixiang; Wolbeck, John; Xu Xiyan [School of Earth and Environmental Sciences, Queens College, City University of New York, NY 11367 (United States); Ricciuto, Daniel [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Li Runze [Department of Statistics, Pennsylvania State University, University Park, PA 16802 (United States); Nilsson, Mats [Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umeaa (Sweden); Aires, Luis [CESAM and Department of Environmental Engineering, School of Technology and Management, Polytechnic Institute of Leiria (Portugal); Albertson, John D [Department of Civil and Environmental Engineering, Duke University, Durham, NC 22708-0287 (United States); Ammann, Christof [Federal Research Station Agroscope Reckenholz-Taenikon, Reckenholzstrasse 191, 8046 Zuerich (Switzerland); Arain, M Altaf [School of Geography and Earth Sciences, McMaster University, Hamilton, ON, L8S 4K1 (Canada); De Araujo, Alessandro C [Instituto Nacional de Pesquisas da Amazonia, Programa LBA, Campus-II, Manaus-Amazonas 69060 (Brazil); Aubinet, Marc [University of Liege, Gembloux Agro-Bio Tech, Unit of Biosystem Physics, 2 Passage des Deportes, 5030 Gembloux (Belgium); Aurela, Mika [Finnish Meteorological Institute, Climate Change Research, FI-00101 Helsinki (Finland); Barcza, Zoltan [Department of Meteorology, Eoetvoes Lorand University, H-1117 Budapest, Pazmany setany 1/A (Hungary); Barr, Alan [Climate Research Division, Environment Canada, Saskatoon, SK, S7N 3H5 (Canada); Berbigier, Paul [INRA, UR1263 EPHYSE, Villenave d' Ornon F-33883 (France); Beringer, Jason [School of Geography and Environmental Science, Monash University, Clayton, Victoria 3800 (Australia); Bernhofer, Christian [Institute of Hydrology and Meteorology, Dresden University of Technology, Pienner Strasse 23, D-01737, Tharandt (Germany)

    2010-07-15

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO{sub 2} exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid- and high-latitudes, (2) a strong function of dryness at mid- and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 deg. N). The sensitivity of NEE to mean annual temperature breaks down at {approx} 16 deg. C (a threshold value of mean annual temperature), above which no further increase of CO{sub 2} uptake with temperature was observed and dryness influence overrules temperature influence.

  10. Climate control of terrestrial carbon exchange across biomes and continents

    International Nuclear Information System (INIS)

    Yi Chuixiang; Wolbeck, John; Xu Xiyan; Ricciuto, Daniel; Li Runze; Nilsson, Mats; Aires, Luis; Albertson, John D; Ammann, Christof; Arain, M Altaf; De Araujo, Alessandro C; Aubinet, Marc; Aurela, Mika; Barcza, Zoltan; Barr, Alan; Berbigier, Paul; Beringer, Jason; Bernhofer, Christian

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO 2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid- and high-latitudes, (2) a strong function of dryness at mid- and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 deg. N). The sensitivity of NEE to mean annual temperature breaks down at ∼ 16 deg. C (a threshold value of mean annual temperature), above which no further increase of CO 2 uptake with temperature was observed and dryness influence overrules temperature influence.

  11. Electronics

    Science.gov (United States)

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  12. Shift of biome patterns due to simulated climate variability and climate change

    International Nuclear Information System (INIS)

    Claussen, M.

    1993-01-01

    The variability of simulated equilibrium-response patterns of biomes caused by simulated climate variability and climate shift is analysed. This investigation is based on various realisations of simulated present-day climate and climate shift. It has been found that the difference between biomes computed from three 10-year climatologies and from the corresponding 30-year climatology, simulated by the Hamburg climate model at T21 resolution, amounts to approximately 6% of the total land area, Antarctica excluded. This difference is mainly due to differences in annual moisture availability and winter temperatures. When intercomparing biomes from the 10-year climatologies a 10% difference is seen, but there is no unique difference pattern. In contrast to the interdecadal variability, the shift of conditions favorable for biomes due to a shift in climate in the next 100 years, caused by an increase in sea-surface temperatures and atmospheric CO 2 , reveals a unique trend pattern. It turns out that the strongest and most significant signal is the north-east shift of conditions for boreal biomes. This signal is caused by an increase of annual temperature sums as well as mean temperatures of the coldest and warmest months. Trends in annual moisture availability are of secondary importance globally. Regionally, a decrease in water availability affects biomes in Central and East Europe and an increase of water availability leads to a potential increase in tropical rain forest. In total, all differences amount to roughly 30% of the total land surface, Antarctica excluded. (orig./KW)

  13. Effects of Government Grassland Conservation Policy on Household Livelihoods and Dependence on Local Grasslands: Evidence from Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Bingzhen Du

    2016-12-01

    Full Text Available Grassland degradation intensifies human-environment conflicts and adversely affects local residents’ livelihoods. To reduce grassland degradation in Inner Mongolia, China, the government has enforced (since 1998 a series of grassland conservation and management policies that restrict the use of grasslands. To ease the impact on the residents’ livelihoods, the national and regional governments have offered a series of top-down arrangements to stimulate sustainable use of the grasslands. Simultaneously, local households spontaneously developed bottom-up countermeasures. To determine the effects of these processes, we interviewed members of 135 households using a mix of qualitative and quantitative methods. We analyzed the effects on household dependence on local grasslands and on perceptions of the future of grassland use. Our findings show that the implementation of the grassland conservation policies significantly affected household livelihoods, which in turn affected household use of natural assets (primarily the land, their agricultural assets (farming and grazing activities and their financial assets (income and consumption, resulting in fundamental transformation of their lifestyles. The households developed adaptation measures to account for the dependence of their livelihood on local ecosystems by initializing strategies, such as seeking off-farm work, leasing pasture land, increasing purchases of fodder for stall-fed animals and altering their diet and fuel consumption to compensate for their changing livelihoods.

  14. The phylogeny and biogeography of Hakea (Proteaceae) reveals the role of biome shifts in a continental plant radiation.

    Science.gov (United States)

    Cardillo, Marcel; Weston, Peter H; Reynolds, Zoe K M; Olde, Peter M; Mast, Austin R; Lemmon, Emily M; Lemmon, Alan R; Bromham, Lindell

    2017-08-01

    The frequency of evolutionary biome shifts during diversification has important implications for our ability to explain geographic patterns of plant diversity. Recent studies present several examples of biome shifts, but whether frequencies of biome shifts closely reflect geographic proximity or environmental similarity of biomes remains poorly known. We explore this question by using phylogenomic methods to estimate the phylogeny of Hakea, a diverse Australian genus occupying a wide range of biomes. Model-based estimation of ancestral regions indicates that Hakea began diversifying in the Mediterranean biome of southern Australia in the Middle Eocene-Early Oligocene, and dispersed repeatedly into other biomes across the continent. We infer around 47 shifts between biomes. Frequencies of shifts between pairs of biomes are usually similar to those expected from their geographic connectedness or climatic similarity, but in some cases are substantially higher or lower than expected, perhaps reflecting how readily key physiological traits can be modified to adapt lineages to new environments. The history of frequent biome-shifting is reflected in the structure of present-day assemblages, which tend to be more phylogenetically diverse than null-model expectations. The case of Hakea demonstrates that the radiation of large plant clades across wide geographic areas need not be constrained by dispersal limitation or conserved adaptations to particular environments. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  15. Microbial Diversity in Cerrado Biome (Neotropical Savanna Soils.

    Directory of Open Access Journals (Sweden)

    Alinne Pereira de Castro

    Full Text Available The Cerrado, the largest savanna region in South America, is located in central Brazil. Cerrado physiognomies, which range from savanna grasslands to forest formations, combined with the highly weathered, acidic clay Cerrado soils form a unique ecoregion. In this study, high-throughput sequencing of ribosomal RNA genes was combined with shotgun metagenomic analysis to explore the taxonomic composition and potential functions of soil microbial communities in four different vegetation physiognomies during both dry and rainy seasons. Our results showed that changes in bacterial, archaeal, and fungal community structures in cerrado denso, cerrado sensu stricto, campo sujo, and gallery forest soils strongly correlated with seasonal patterns of soil water uptake. The relative abundance of AD3, WPS-2, Planctomycetes, Thermoprotei, and Glomeromycota typically decreased in the rainy season, whereas the relative abundance of Proteobacteria and Ascomycota increased. In addition, analysis of shotgun metagenomic data revealed a significant increase in the relative abundance of genes associated with iron acquisition and metabolism, dormancy, and sporulation during the dry season, and an increase in the relative abundance of genes related to respiration and DNA and protein metabolism during the rainy season. These gene functional categories are associated with adaptation to water stress. Our results further the understanding of how tropical savanna soil microbial communities may be influenced by vegetation covering and temporal variations in soil moisture.

  16. Quantifying soil moisture impacts on light use efficiency across biomes.

    Science.gov (United States)

    Stocker, Benjamin D; Zscheischler, Jakob; Keenan, Trevor F; Prentice, I Colin; Peñuelas, Josep; Seneviratne, Sonia I

    2018-06-01

    Terrestrial primary productivity and carbon cycle impacts of droughts are commonly quantified using vapour pressure deficit (VPD) data and remotely sensed greenness, without accounting for soil moisture. However, soil moisture limitation is known to strongly affect plant physiology. Here, we investigate light use efficiency, the ratio of gross primary productivity (GPP) to absorbed light. We derive its fractional reduction due to soil moisture (fLUE), separated from VPD and greenness changes, using artificial neural networks trained on eddy covariance data, multiple soil moisture datasets and remotely sensed greenness. This reveals substantial impacts of soil moisture alone that reduce GPP by up to 40% at sites located in sub-humid, semi-arid or arid regions. For sites in relatively moist climates, we find, paradoxically, a muted fLUE response to drying soil, but reduced fLUE under wet conditions. fLUE identifies substantial drought impacts that are not captured when relying solely on VPD and greenness changes and, when seasonally recurring, are missed by traditional, anomaly-based drought indices. Counter to common assumptions, fLUE reductions are largest in drought-deciduous vegetation, including grasslands. Our results highlight the necessity to account for soil moisture limitation in terrestrial primary productivity data products, especially for drought-related assessments. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  17. USING LUDIC ACTIVITIES TO EXPLAIN THE BIOME CONCEPT

    Directory of Open Access Journals (Sweden)

    Aline Riccioni de Melos

    2015-12-01

    Full Text Available This paper contributes to research on the role of ludic activities in teaching and learning physical geography content during the last four years of primary school. We question the discourse that identifies students’ lack of interest as the obstacle to teaching physical geography. This study contributes by questioning this obstacle. We note that few studies exist on this topic, according to the CAPES (Coordination for higher Education Staff Development dissertation database, in 2011 only five were completed. The theoretical basis for the study considers work by Graciolli (2009, Silva et al. (2010, Rupel (2011 and Freitas and Salvi (2011, authors who defend the use of ludic activities in teaching methodology. In 2010, the “Biome Game” for 6th year students was developed based on this theoretical framework as part of the required course “Supervised Practice”. The goal of the activity was to think about how the concept of biome was created, and the methodology used valued recreational approaches. The empirical results of this experiment, which involved developing and implementing the game during the Supervised Practice course, demonstrate the importance of ludic pedagogical strategies for teaching physical geography in Brazilian primary education. O presente artigo traz contribuições de pesquisa sobre a função da ludicidade no ensino-aprendizagem de conteúdos da geografia física, no segundo segmento do ensino fundamental. Tal questão problematiza o discurso sobre o desinteresse dos alunos, como significativo obstáculo para a didática da geografia física. A pertinência do presente estudo está em reconhecer esta questão, tendo em vista que existem poucos estudos na área, totalizando em 2011, segundo o banco de dissertações da CAPES, somente cinco trabalhos concluídos. Nossa investigação dialoga com Graciolli (2009, Silva et al. (2010, Rupel (2011 e Freitas e Salvi (2011, autores dedicados à defesa da utilização de

  18. Biogeochemical cycling in terrestrial ecosystems of the Caatinga Biome.

    Science.gov (United States)

    Menezes, R S C; Sampaio, E V S B; Giongo, V; Pérez-Marin, A M

    2012-08-01

    The biogeochemical cycles of C, N, P and water, the impacts of land use in the stocks and flows of these elements and how they can affect the structure and functioning of Caatinga were reviewed. About half of this biome is still covered by native secondary vegetation. Soils are deficient in nutrients, especially N and P. Average concentrations of total soil P and C in the top layer (0-20 cm) are 196 mg kg(-1) and 9.3 g kg(-1), corresponding to C stocks around 23 Mg ha(-1). Aboveground biomass of native vegetation varies from 30 to 50 Mg ha(-1), and average root biomass from 3 to 12 Mg ha(-1). Average annual productivities and biomass accumulation in different land use systems vary from 1 to 7 Mg ha(-1) year(-1). Biological atmospheric N2 fixation is estimated to vary from 3 to 11 kg N ha(-1) year-1 and 21 to 26 kg N ha(-1) year(-1) in mature and secondary Caatinga, respectively. The main processes responsible for nutrient and water losses are fire, soil erosion, runoff and harvest of crops and animal products. Projected climate changes in the future point to higher temperatures and rainfall decreases. In face of the high intrinsic variability, actions to increase sustainability should improve resilience and stability of the ecosystems. Land use systems based on perennial species, as opposed to annual species, may be more stable and resilient, thus more adequate to face future potential increases in climate variability. Long-term studies to investigate the potential of the native biodiversity or adapted exotic species to design sustainable land use systems should be encouraged.

  19. Does a General Temperature-Dependent Q10 Model of Soil Respiration Exist at Biome and Global Scale?

    Institute of Scientific and Technical Information of China (English)

    Hua CHEN; Han-Qin TIAN

    2005-01-01

    Soil respiration (SR) is commonly modeled by a Q10 (an indicator of temperature sensitivity)function in ecosystem models. Q10is usually treated as a constant of 2 in these models, although Q10 value of SR often decreases with increasing temperatures. It remains unclear whether a general temperaturedependent Q10 model of SR exists at biome and global scale. In this paper, we have compiled the long-term Q10 data of 38 SR studies ranging from the Boreal, Temperate, to Tropical/Subtropical biome on four continents.Our analysis indicated that the general temperature-dependent biome Q10 models of SR existed, especially in the Boreal and Temperate biomes. A single-exponential model was better than a simple linear model in fitting the average Q10 values at the biome scale. Average soil temperature is a better predictor of Q10 value than average air temperature in these models, especially in the Boreal biome. Soil temperature alone could explain about 50% of the Q10 variations in both the Boreal and Temperate biome single-exponential Q10 model. Q10 value of SR decreased with increasing soil temperature but at quite different rates among the three biome Q10 models. The k values (Q10 decay rate constants) were 0.09, 0.07, and 0.02/℃ in the Boreal, Temperate, and Tropical/Subtropical biome, respectively, suggesting that Q10 value is the most sensitive to soil temperature change in the Boreal biome, the second in the Temperate biome, and the least sensitive in the Tropical/Subtropical biome. This also indirectly confirms that acclimation of SR in many soil warming experiments probably occurs. The k value in the "global" single-exponential Q10 model which combined both the Boreal and Temperate biome data set was 0.08/℃. However, the global general temperature-dependent Q10model developed using the data sets of the three biomes is not adequate for predicting Q10 values of SR globally.The existence of the general temperature-dependent Q10 models of SR in the Boreal and

  20. Indirect Effects of Energy Development in Grasslands

    Science.gov (United States)

    Duquette, Cameron Albert

    Grassland landscapes in North America are undergoing rapid industrialization due to energy development facilitated by the growing popularity of fracking and horizontal drilling technology. Each year over 3 million hectares are lost from grassland and shrubland habitats to well infrastructure. Direct footprints from energy infrastructure cause impacts to vegetation cover, available cattle forage, carbon sequestration potential, and usable space for wildlife. However, legacy effects from well construction and noise pollution, light pollution, and altered viewsheds have the potential to impact areas beyond this direct footprint, causing additive and persistent changes to nearby grassland function. While these additional areas may be small on a well pad basis, they may have substantial cumulative impacts over time. To investigate these effects via a diversity of mechanisms, we studied the seasonal habitat selection of northern bobwhite (Colinus virginianus, hereafter bobwhite) in an energy-producing landscape to evaluate space use patterns relative to energy infrastructure. Habitat selection was modeled in the breeding and nonbreeding season using resource Utilization functions (RUFs). We then investigated patterns of vegetation, arthropod, and soil characteristics surrounding well pads to assess small scale environmental gradients extending away from drilling pads via a combination of multivariate and univariate techniques (i.e., Nonmetric dimensional scaling and ANOVA). We found minimal avoidance of energy structures by quail, suggesting a tolerance of moderate development levels. All small-scale effects studied except for soil moisture were impacted at the pad itself (P < 0.01). Off-pad impacts to arthropod abundance and biomass were spatially limited to areas close to pads, while vegetation cover was typically lower than the surrounding habitat beyond 10 m of pads. Soil surface temperature was higher at distances close to well pads, and soil moisture was not

  1. The role of grasslands in food security and climate change.

    Science.gov (United States)

    O'Mara, F P

    2012-11-01

    Grasslands are a major part of the global ecosystem, covering 37 % of the earth's terrestrial area. For a variety of reasons, mostly related to overgrazing and the resulting problems of soil erosion and weed encroachment, many of the world's natural grasslands are in poor condition and showing signs of degradation. This review examines their contribution to global food supply and to combating climate change. Grasslands make a significant contribution to food security through providing part of the feed requirements of ruminants used for meat and milk production. Globally, this is more important in food energy terms than pig meat and poultry meat. Grasslands are considered to have the potential to play a key role in greenhouse gas mitigation, particularly in terms of global carbon storage and further carbon sequestration. It is estimated that grazing land management and pasture improvement (e.g. through managing grazing intensity, improved productivity, etc) have a global technical mitigation potential of almost 1·5 Gt CO(2) equivalent in 2030, with additional mitigation possible from restoration of degraded lands. Milk and meat production from grassland systems in temperate regions has similar emissions of carbon dioxide per kilogram of product as mixed farming systems in temperate regions, and, if carbon sinks in grasslands are taken into account, grassland-based production systems can be as efficient as high-input systems from a greenhouse gas perspective. Grasslands are important for global food supply, contributing to ruminant milk and meat production. Extra food will need to come from the world's existing agricultural land base (including grasslands) as the total area of agricultural land has remained static since 1991. Ruminants are efficient converters of grass into humanly edible energy and protein and grassland-based food production can produce food with a comparable carbon footprint as mixed systems. Grasslands are a very important store of carbon, and

  2. Evolutionary biology and anthropology suggest biome reconstitution as a necessary approach toward dealing with immune disorders.

    Science.gov (United States)

    Parker, William; Ollerton, Jeff

    2013-01-01

    Industrialized society currently faces a wide range of non-infectious, immune-related pandemics. These pandemics include a variety of autoimmune, inflammatory and allergic diseases that are often associated with common environmental triggers and with genetic predisposition, but that do not occur in developing societies. In this review, we briefly present the idea that these pandemics are due to a limited number of evolutionary mismatches, the most damaging being 'biome depletion'. This particular mismatch involves the loss of species from the ecosystem of the human body, the human biome, many of which have traditionally been classified as parasites, although some may actually be commensal or even mutualistic. This view, evolved from the 'hygiene hypothesis', encompasses a broad ecological and evolutionary perspective that considers host-symbiont relations as plastic, changing through ecological space and evolutionary time. Fortunately, this perspective provides a blueprint, termed 'biome reconstitution', for disease treatment and especially for disease prevention. Biome reconstitution includes the controlled and population-wide reintroduction (i.e. domestication) of selected species that have been all but eradicated from the human biome in industrialized society and holds great promise for the elimination of pandemics of allergic, inflammatory and autoimmune diseases.

  3. An intercomparison of biogenic emissions estimates from BEIS2 and BIOME: Reconciling the differences

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, J.G. [Alpine Geophysics, Pittsburgh, PA (United States); Emigh, R.A. [Alpine Geophysics, Boulder, CO (United States); Pierce, T.E. [Atmospheric Characterization and Modeling Division/NOAA, Research Triangle Park, NC (United States)

    1996-12-31

    Biogenic emissions play a critical role in urban and regional air quality. For instance, biogenic emissions contribute upwards of 76% of the daily hydrocarbon emissions in the Atlanta, Georgia airshed. The Biogenic Emissions Inventory System-Version 2.0 (BEIS2) and the Biogenic Model for Emissions (BIOME) are two models that compute biogenic emissions estimates. BEIS2 is a FORTRAN-based system, and BIOME is an ARC/INFO{reg_sign} - and SAS{reg_sign}-based system. Although the technical formulations of the models are similar, the models produce different biogenic emissions estimates for what appear to be essentially the same inputs. The goals of our study are the following: (1) Determine why BIOME and BEIS2 produce different emissions estimates; (2) Attempt to understand the impacts that the differences have on the emissions estimates; (3) Reconcile the differences where possible; and (4) Present a framework for the use of BEIS2 and BIOME. In this study, we used the Coastal Oxidant Assessment for Southeast Texas (COAST) biogenics data which were supplied to us courtesy of the Texas Natural Resource Conservation Commission (TNRCC), and we extracted the BEIS2 data for the same domain. We compared the emissions estimates of the two models using their respective data sets BIOME Using TNRCC data and BEIS2 using BEIS2 data.

  4. Measurement of grassland evaporation using a surface-layer ...

    African Journals Online (AJOL)

    Measurement of grassland evaporation using a surface-layer scintillometer. ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search ... of soil heat flux and net irradiance, evaporation rates were calculated as a residual of the ...

  5. Ecological mechanisms underlying arthropod species diversity in grasslands.

    Science.gov (United States)

    Joern, Anthony; Laws, Angela N

    2013-01-01

    Arthropods are an important component of grassland systems, contributing significantly to biodiversity and ecosystem structure and function. Climate, fire, and grazing by large herbivores are important drivers in grasslands worldwide. Arthropod responses to these drivers are highly variable and clear patterns are difficult to find, but responses are largely indirect with respect to changes in resources, species interactions, habitat structure, and habitat heterogeneity resulting from interactions among fire, grazing, and climate. Here, we review these ecological mechanisms influencing grassland arthropod diversity. We summarize hypotheses describing species diversity at local and regional scales and then discuss specific factors that may affect arthropod diversity in grassland systems. These factors include direct and indirect effects of grazing, fire, and climate, species interactions, above- and belowground interactions, and landscape-level effects.

  6. Soil Organic Carbon Responses to Forest Expansion on Mountain Grasslands

    DEFF Research Database (Denmark)

    Guidi, Claudia

    . Changes in labile soil C were assessed by carbohydrate and thermal analyses of soil samples and fractions. Forest expansion on mountain grasslands caused a decrease in SOC stocks within the mineral soil. The SOC accumulation within the organic layers following forest establishment could not fully...... and thermally labile to resistant components decreased from grassland to forest successional stages, and corresponded to decreased SOC protection within stable aggregates. This PhD thesis showed that mineral SOC stocks and physically protected SOC fractions decreased following forest expansion on mountain......Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties...

  7. Impact intensities of climatic changes on grassland ecosystems in ...

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-03-22

    Mar 22, 2012 ... Construction of the impact intensity model of climatic changes on grassland ecosystem ... the temperature and rainfall (Sun and Mu, 2011). Thus, the study ... of the equation, the study transformed the measurement unit Mu of.

  8. Methods for evaluation of the invasibility of grasslands

    DEFF Research Database (Denmark)

    Strandberg, M. T.; Strandberg, B.; Erneberg, M.

    The number of non-native plant species in Danish dry acidic grasslands was positively correlated with the cover of disturbance in the form of molehills, anthills, mouseholes and erosion due trampling or digging by large herbivores/livestock. Natural disturbance in acidic grassland ecosystems...... not grazed by livestock therefore is important for the occurrence of non-native species, and probably also for the occurrence of a high native floristic diversity....

  9. PV water pumping systems for grassland and farmland conservation

    OpenAIRE

    Campana, Pietro Elia

    2013-01-01

    Grassland degradation is considered as one of the worst environmental and economic problems in China because of the negative impacts on water and food security. The application of the photovoltaic water pumping (PVWP) technology for irrigation is an innovative and sustainable solution to curb the progress of grassland desertification and to promote the conservation of farmland in remote areas. The combination of PVWP with water saving irrigation techniques and the sustainable management of th...

  10. Impacts of Future Grassland Changes on Surface Climate in Mongolia

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    2013-01-01

    Full Text Available Climate change caused by land use/cover change (LUCC is becoming a hot topic in current global change, especially the changes caused by the grassland degradation. In this paper, based on the baseline underlying surface data of 1993, the predicted underlying surface data which can be derived through overlaying the grassland degradation information to the map of baseline underlying surface, and the atmospheric forcing data of RCP 6.0 from CMIP5, climatological changes caused by future grassland changes for the years 2010–2020 and 2040–2050 with the Weather Research Forecast model (WRF are simulated. The model-based analysis shows that future grassland degradation will significantly result in regional climate change. The grassland degradation in future could lead to an increasing trend of temperature in most areas and corresponding change range of the annual average temperature of −0.1°C–0.4°C, and it will cause a decreasing trend of precipitation and corresponding change range of the annual average precipitation of 10 mm–50 mm. This study identifies lines of evidence for effects of future grassland degradation on regional climate in Mongolia which provides meaningful decision-making information for the development and strategy plan making in Mongolia.

  11. Concluding remarks: overall impacts on biodiversity and future perspectives for conservation in the Pantanal biome.

    Science.gov (United States)

    Alho, C J R

    2011-04-01

    The Pantanal biome is characterised by seasonal flooding which determines specific ecosystem processes, with the occurrence of adapted plants and animals to the annual shrinking and expansion of habitats due to the seasonal hydrological regime. Biodiversity abundance varies during the dry and wet seasons. The Pantanal's biodiversity is a fundamental component of ecosystem services for human society, including nutrient cycling, fish production, ecotourism, carbon storage, flood control, among others, which are relevant to regional and global environmental consequences. The biome has been impacted by the conversion of natural vegetation into agricultural fields and pasture for cattle raising, with alteration and loss of natural habitats and biodiversity. Major negative impacts occur in uplands, with drastic deforestation of savanna vegetation, where main rivers feeding the Pantanal have their springs. This article discusses future needs and priorities for ecological research, in order to better understand the biome's natural system, to achieve conservation and sustainable use.

  12. Concluding remarks: overall impacts on biodiversity and future perspectives for conservation in the Pantanal biome

    Directory of Open Access Journals (Sweden)

    CJR. Alho

    Full Text Available The Pantanal biome is characterised by seasonal flooding which determines specific ecosystem processes, with the occurrence of adapted plants and animals to the annual shrinking and expansion of habitats due to the seasonal hydrological regime. Biodiversity abundance varies during the dry and wet seasons. The Pantanal's biodiversity is a fundamental component of ecosystem services for human society, including nutrient cycling, fish production, ecotourism, carbon storage, flood control, among others, which are relevant to regional and global environmental consequences. The biome has been impacted by the conversion of natural vegetation into agricultural fields and pasture for cattle raising, with alteration and loss of natural habitats and biodiversity. Major negative impacts occur in uplands, with drastic deforestation of savanna vegetation, where main rivers feeding the Pantanal have their springs. This article discusses future needs and priorities for ecological research, in order to better understand the biome's natural system, to achieve conservation and sustainable use.

  13. The Relative Importance of Spatial and Local Environmental Factors in Determining Beetle Assemblages in the Inner Mongolia Grassland.

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Yu

    Full Text Available The aim of this paper is to increase understanding of the relative importance of the input of geographic and local environmental factors on richness and composition of epigaeic steppe beetles (Coleoptera: Carabidae and Tenebrionidae along a geographic (longitudinal/precipitation gradient in the Inner Mongolia grassland. Specifically, we evaluate the associations of environmental variables representing climate and environmental heterogeneity with beetle assemblages. Beetles were sampled using pitfall traps at 25 sites scattered across the full geographic extent of the study biome in 2011-2012. We used variance partitioning techniques and multi-model selection based on the Akaike information criterion to assess the relative importance of the spatial and environmental variables on beetle assemblages. Species richness and abundance showed unimodal patterns along the geographic gradient. Together with space, climate variables associated with precipitation, water-energy balance and harshness of climate had strong explanatory power in richness pattern. Abundance pattern showed strongest association with variation in temperature and environmental heterogeneity. Climatic factors associated with temperature and precipitation variables and the interaction between climate with space were able to explain a substantial amount of variation in community structure. In addition, the turnover of species increased significantly as geographic distances increased. We confirmed that spatial and local environmental factors worked together to shape epigaeic beetle communities along the geographic gradient in the Inner Mongolia grassland. Moreover, the climate features, especially precipitation, water-energy balance and temperature, and the interaction between climate with space and environmental heterogeneity appeared to play important roles on controlling richness and abundance, and species compositions of epigaeic beetles.

  14. Habitat associations of migrating and overwintering grassland birds in Southern Texas

    Science.gov (United States)

    Igl, Lawrence D.; Ballard, Bart M.

    1999-01-01

    We report on the habitat associations of 21 species of grassland birds overwintering in or migrating through southern Texas, during 1991-1992 and 1992-1993. Ninety percent of our grassland bird observations were made during winter and spring, and only 10% occurred during fall. Grassland species made up a high proportion of the total bird densities in grassland and shrub-grassland habitats, but much lower proportions in the habitats with more woody vegetation. Fewer grassland species were observed in grassland and woodland than in brushland, parkland, and shrub-grassland habitats. Grassland birds generally were found in higher densities in habitats that had woody canopy coverage of < 30%; densities of grassland birds were highest in shrub-grassland habitat and lowest in woodland habitat. Species that are grassland specialists on their breeding grounds tended to be more habitat specific during the nonbreeding season compared to shrub-grassland specialists, which were more general in their nonbreeding-habitat usage. Nonetheless, our data demonstrate that grassland birds occur in a variety of habitats during the nonbreeding season and seem to occupy a broader range of habitats than previously described.

  15. BOREAS RSS-8 BIOME-BGC Model Simulations at Tower Flux Sites in 1994

    Science.gov (United States)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Kimball, John

    2000-01-01

    BIOME-BGC is a general ecosystem process model designed to simulate biogeochemical and hydrologic processes across multiple scales (Running and Hunt, 1993). In this investigation, BIOME-BGC was used to estimate daily water and carbon budgets for the BOREAS tower flux sites for 1994. Carbon variables estimated by the model include gross primary production (i.e., net photosynthesis), maintenance and heterotrophic respiration, net primary production, and net ecosystem carbon exchange. Hydrologic variables estimated by the model include snowcover, evaporation, transpiration, evapotranspiration, soil moisture, and outflow. The information provided by the investigation includes input initialization and model output files for various sites in tabular ASCII format.

  16. Where do the treeless tundra areas of northern highlands fit in the global biome system: toward an ecologically natural subdivision of the tundra biome.

    Science.gov (United States)

    Virtanen, Risto; Oksanen, Lauri; Oksanen, Tarja; Cohen, Juval; Forbes, Bruce C; Johansen, Bernt; Käyhkö, Jukka; Olofsson, Johan; Pulliainen, Jouni; Tømmervik, Hans

    2016-01-01

    According to some treatises, arctic and alpine sub-biomes are ecologically similar, whereas others find them highly dissimilar. Most peculiarly, large areas of northern tundra highlands fall outside of the two recent subdivisions of the tundra biome. We seek an ecologically natural resolution to this long-standing and far-reaching problem. We studied broad-scale patterns in climate and vegetation along the gradient from Siberian tundra via northernmost Fennoscandia to the alpine habitats of European middle-latitude mountains, as well as explored those patterns within Fennoscandian tundra based on climate-vegetation patterns obtained from a fine-scale vegetation map. Our analyses reveal that ecologically meaningful January-February snow and thermal conditions differ between different types of tundra. High precipitation and mild winter temperatures prevail on middle-latitude mountains, low precipitation and usually cold winters prevail on high-latitude tundra, and Scandinavian mountains show intermediate conditions. Similarly, heath-like plant communities differ clearly between middle latitude mountains (alpine) and high-latitude tundra vegetation, including its altitudinal extension on Scandinavian mountains. Conversely, high abundance of snowbeds and large differences in the composition of dwarf shrub heaths distinguish the Scandinavian mountain tundra from its counterparts in Russia and the north Fennoscandian inland. The European tundra areas fall into three ecologically rather homogeneous categories: the arctic tundra, the oroarctic tundra of northern heights and mountains, and the genuinely alpine tundra of middle-latitude mountains. Attempts to divide the tundra into two sub-biomes have resulted in major discrepancies and confusions, as the oroarctic areas are included in the arctic tundra in some biogeographic maps and in the alpine tundra in others. Our analyses based on climate and vegetation criteria thus seem to resolve the long-standing biome

  17. Does Evapotranspiration Increase When Forests are converted to Grasslands?

    Science.gov (United States)

    Varcoe, Robert; Sterling, Shannon

    2017-04-01

    The conversion of forests to grasslands (FGC) is a widespread land cover change (LCC) and is also among the most commonly studied changes with respect to its impact on ET; such research employs a variety of experimental approaches, including, paired catchment (PC), Budyko and land surface models (LSM), and measurement methods, including the catchment water balance (CWB), eddy covariance (EC) and remote sensing (RS). Until recently, there has been consensus in the scientific literature that rates of ET decrease when a forest is converted to grassland; however, this consensus has recently come into question. Williams (2012) applied the Budyko framework to a global network of eddy covariance measurements with the results that grasslands have a 9% greater evaporative index than forests. In addition, HadGEM2, a recent Hadley Centre LSM, produced increased ET in the northern Amazon Basin after simulating global scale tropical deforestation (Brovkin et al., 2015). Here we present an analysis of available estimates of how ET rates change with FGC to increase our understanding of the forest - grassland-ET paradigm. We used two datasets to investigate the impacts land cover change on ET. I compiled a dataset of change in ET with land cover change (ΔETLCC) using published experiments that compare forest and grassland ET under conditions controlled for meteorological and landscape influences. Using the ΔETLCC dataset, we show that, in all cases, forest ET is higher than grassland under controlled conditions. Results suggest that the eddy covariance method measures smaller changes in ET when forests are converted to grasslands, though more data are needed for this result to be statistically significant. Finally, GETA2.0, a new global dataset of annual ET, projects that forest ET is greater than grassland, except at high latitudes and areas where orography influences precipitation (P). The data included in this study represent the data available on forest and grassland ET

  18. Carbon storage in permafrost and soils of the mammoth tundra-steppe biome: role in the global carbon budget

    Science.gov (United States)

    N.S. Zimov; S.A. Zimov; A.E. Zimova; G.M. Zimova; V.I. Chuprynin; F.S. Chapin

    2009-01-01

    During the Last Glacial Maximum (LGM), atmospheric CO2 concentration was 80-100 ppmv lower than in preindustrial times. At that time steppe-tundra was the most extensive biome on Earth. Some authors assume that C storage in that biome was very small, similar to today's deserts, and that the terrestrial carbon (C) reservoir increased at the...

  19. The Biological Observation Matrix (BIOM) format or: how I learned to stop worrying and love the ome-ome.

    Science.gov (United States)

    McDonald, Daniel; Clemente, Jose C; Kuczynski, Justin; Rideout, Jai Ram; Stombaugh, Jesse; Wendel, Doug; Wilke, Andreas; Huse, Susan; Hufnagle, John; Meyer, Folker; Knight, Rob; Caporaso, J Gregory

    2012-07-12

    We present the Biological Observation Matrix (BIOM, pronounced "biome") format: a JSON-based file format for representing arbitrary observation by sample contingency tables with associated sample and observation metadata. As the number of categories of comparative omics data types (collectively, the "ome-ome") grows rapidly, a general format to represent and archive this data will facilitate the interoperability of existing bioinformatics tools and future meta-analyses. The BIOM file format is supported by an independent open-source software project (the biom-format project), which initially contains Python objects that support the use and manipulation of BIOM data in Python programs, and is intended to be an open development effort where developers can submit implementations of these objects in other programming languages. The BIOM file format and the biom-format project are steps toward reducing the "bioinformatics bottleneck" that is currently being experienced in diverse areas of biological sciences, and will help us move toward the next phase of comparative omics where basic science is translated into clinical and environmental applications. The BIOM file format is currently recognized as an Earth Microbiome Project Standard, and as a Candidate Standard by the Genomic Standards Consortium.

  20. Large-scale impact of climate change vs. land-use change on future biome shifts in Latin America

    NARCIS (Netherlands)

    Boit, Alice; Sakschewski, Boris; Boysen, Lena; Cano-Crespo, Ana; Clement, Jan; Garcia-alaniz, Nashieli; Kok, Kasper; Kolb, Melanie; Langerwisch, Fanny; Rammig, Anja; Sachse, René; Eupen, van Michiel; Bloh, von Werner; Clara Zemp, Delphine; Thonicke, Kirsten

    2016-01-01

    Climate change and land-use change are two major drivers of biome shifts causing habitat and biodiversity loss. What is missing is a continental-scale future projection of the estimated relative impacts of both drivers on biome shifts over the course of this century. Here, we provide such a

  1. Impacts of fire and grazing management on South Africa’s moist highland grasslands: A case study of the Steenkampsberg Plateau, Mpumalanga, South Africa

    Directory of Open Access Journals (Sweden)

    Ian T. Little

    2015-11-01

    Full Text Available Background: Grasslands are heavily utilised for livestock agriculture and the resultant degradation through mismanagement contributes to an estimated 60% of this biome being permanently transformed. This study focused on the impact of fire and grazing in moist highland grasslands. Objectives: To determine the contribution of burning frequency and grazing intensity combined (for domestic livestock and indigenous ungulates on vegetation structure heterogeneity and species diversity. Methods: Eight study sites under different management regimes were sampled over two summers. Vegetation structure characteristics and diversity data were collected monthly within multiple replicates in each study site. A disc pasture meter was used to assess standing biomass. Differences in vegetation structure characteristics, plant community composition and plant species assemblage structure across sites were statistically analysed using analyses of variance, indicator species analyses, multidimensional scaling ordinations and two-way cluster analyses. Results: The combination of heavy grazing and annual burning leads to a distinct plant community dominated by disturbance specialist species. Selective grazing by indigenous herbivores promotes a community of unpalatable species. This study illustrates that fenced indigenous herbivores, even at moderate stocking densities, have a greater detrimental impact on plant diversity and structure than do domestic livestock. Conclusion: Intensive grazing and burning have a detrimental impact on plant species diversity and structure. This also affects resultant palatability for grazing livestock and fenced game. To promote both grazing quality and ecological integrity we recommend a minimum sustainable ‘fodder capacity’ or standing phytomass of 5000 kg per large-animal unit per hectare for domestic livestock in moist highland grasslands.

  2. Application of Multi-Source Remote Sensing Image in Yunnan Province Grassland Resources Investigation

    Science.gov (United States)

    Li, J.; Wen, G.; Li, D.

    2018-04-01

    Trough mastering background information of Yunnan province grassland resources utilization and ecological conditions to improves grassland elaborating management capacity, it carried out grassland resource investigation work by Yunnan province agriculture department in 2017. The traditional grassland resource investigation method is ground based investigation, which is time-consuming and inefficient, especially not suitable for large scale and hard-to-reach areas. While remote sensing is low cost, wide range and efficient, which can reflect grassland resources present situation objectively. It has become indispensable grassland monitoring technology and data sources and it has got more and more recognition and application in grassland resources monitoring research. This paper researches application of multi-source remote sensing image in Yunnan province grassland resources investigation. First of all, it extracts grassland resources thematic information and conducts field investigation through BJ-2 high space resolution image segmentation. Secondly, it classifies grassland types and evaluates grassland degradation degree through high resolution characteristics of Landsat 8 image. Thirdly, it obtained grass yield model and quality classification through high resolution and wide scanning width characteristics of MODIS images and sample investigate data. Finally, it performs grassland field qualitative analysis through UAV remote sensing image. According to project area implementation, it proves that multi-source remote sensing data can be applied to the grassland resources investigation in Yunnan province and it is indispensable method.

  3. Selection of native trees for intercropping with coffee in the Atlantic Rainforest biome

    NARCIS (Netherlands)

    Souza, de H.N.; Cardoso, I.M.; Fernandes, J.M.; Garcia, F.C.P.; Bonfim, V.R.; Santos, A.C.; Carvalho, A.F.; Mendonca, E.S.

    2010-01-01

    A challenge in establishing agroforestry systems is ensuring that farmers are interested in the tree species, and are aware of how to adequately manage these species. This challenge was tackled in the Atlantic Rainforest biome (Brazil), where a participatory trial with agroforestry coffee systems

  4. A new species of Andocaeculus (Acari, Caeculidae) from the Pampa biome, southern Brazil

    OpenAIRE

    Ana Paula Ott; Ricardo Ott

    2014-01-01

    A new caeculid species Andocaeculus caioi sp. nov. is described from Pampa biome in south Brazil. The species of this family are usually large and strong sclerotized mites with robust and spinulose legs I and II. Until now records of species for South America were known only from Chile and Argentina.

  5. Hantavirus pulmonary syndrome and rodent reservoirs in the savanna-like biome of Brazil's southeastern region.

    Science.gov (United States)

    Limongi, J E; Oliveira, R C; Guterres, A; Costa Neto, S F; Fernandes, J; Vicente, L H B; Coelho, M G; Ramos, V N; Ferreira, M S; Bonvicino, C R; D'Andrea, P S; Lemos, E R S

    2016-04-01

    This paper describes the diversity of rodent fauna in an area endemic for hantavirus cardiopulmonary syndrome (HCPS) in Brazil, the population dynamics and the relationship of rodents with hantavirus in the Cerrado (savanna-like) biome. Additionally, an analysis is made of the partial S segment sequences of the hantaviruses obtained from serologically confirmed human HCPS cases and from rodent specimens. Rodents were collected during four campaigns. Human serum samples were collected from suspected cases of HCPS at hospitals in the state of Minas Gerais. The samples antibody-reactive by ELISA were processed by RT-PCR. The PCR product was amplified and sequenced. Hantavirus was detected only in Necromys lasiurus, the wild rodent species most prevalent in the Cerrado biome (min-max: 50-83·7%). All the six human serum samples were hantavirus seropositive and five showed amplified PCR products. The analysis of the nucleotide sequences showed the circulation of a single genotype, the Araraquara hantavirus. The environmental changes that have occurred in the Cerrado biome in recent decades have favoured N. lasiurus in interspecific competition of habitats, thus increasing the risk of contact between humans and rodent species infected with hantavirus. Our data corroborate the definition of N. lasiurus as the main hantavirus reservoir in the Cerrado biome.

  6. Extreme precipitation patterns and reductions of terrestrial ecosystem production across biomes

    Science.gov (United States)

    Yongguang Zhang; M. Susan Moran; Mark A. Nearing; Guillermo E. Ponce Campos; Alfredo R. Huete; Anthony R. Buda; David D. Bosch; Stacey A. Gunter; Stanley G. Kitchen; W. Henry McNab; Jack A. Morgan; Mitchel P. McClaran; Diane S. Montoya; Debra P.C. Peters; Patrick J. Starks

    2013-01-01

    Precipitation regimes are predicted to shift to more extreme patterns that are characterized by more heavy rainfall events and longer dry intervals, yet their ecological impacts on vegetation production remain uncertain across biomes in natural climatic conditions. This in situ study investigated the effects of these climatic conditions on aboveground net primary...

  7. Himalayan uplift shaped biomes in Miocene temperate Asia: evidence from leguminous Caragana

    Science.gov (United States)

    Ming-Li Zhang; Xiao-Guo Xiang; Juan-Juan Xue; Stewart C. Sanderson; Peter W. Fritsch

    2016-01-01

    Caragana, with distinctive variation in leaf and rachis characters, exhibits three centers of geographic distribution, i.e., Central Asia, the Qinghai-Tibetan Plateau (QTP), and East Asia, corresponding to distinct biomes. Because Caragana species are often ecologically dominant components of the vegetation in these regions, it is regarded as a key taxon for...

  8. The Biome Project: Developing a Legitimate Parallel Curriculum for Physical Education and Life Sciences

    Science.gov (United States)

    Hastie, Peter Andrew

    2013-01-01

    The purpose of this article is to describe the outcomes of a parallel curriculum project between life sciences and physical education. Throughout a 6-week period, students in grades two through five became members of teams that represented different animal species and biomes, and concurrently participated in a season of gymnastics skills and…

  9. Remotely sensed vegetation phenology for describing and predicting the biomes of South Africa

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2011-02-01

    Full Text Available the distribution of the recently redefined biomes be predicted based on remotely sensed, phenology and productivity metrics? Ten-day, 1 km, NDVI AVHRR were analysed for the period 1985 to 2000. Phenological metrics such as start, end and length of the growing...

  10. Modeling Carbon and Water Budgets in the Lushi Basin with Biome-BGC

    Institute of Scientific and Technical Information of China (English)

    Dong Wenjuan; Qi Ye; Li Huimin; Zhou Dajie; Shi Duanhua; Sun Liying

    2005-01-01

    In this article, annual evapotranspiration (ET) and net primary productivity (NPP) of four types of vegetation were estimated for the Lushi basin,a subbasin of the Yellow River in China. These four vegetation types include: deciduous broadleaf forest,evergreen needle leaf forest, dwarf shrub and grass.Biome-BGC--a biogeochemical process model was used to calculate annual ET and NPP for each vegetation type in the study area from 1954 to 2000.Daily microclimate data of 47 years monitored by Lushi meteorological station was extrapolated to cover the basin using MT-CLIM, a mountain microclimate simulator. The output files of MTCLIM were used to feed Biome-BGC. We used average ecophysiological values of each type of vegetation supplied by Numerical Terradynamic Simulation Group (NTSG) in the University of Montana as input ecophysiological constants file.The estimates of daily NPP in early July and annual ET on these four biome groups were compared respectively with field measurements and other studies.Daily gross primary production (GPP) of evergreen needle leaf forest measurements were very dose to the output of Biome-BGC, but measurements of broadleaf forest and dwarf shrub were much smaller than the simulation result. Simulated annual ET and NPP had a significant correlation with precipitation,indicating precipitation is the major environmental factor affecting ET and NPP in the study area.Precipitation also is the key climatic factor for the interannual ET and NPP variations.

  11. Global negative vegetation feedback to climate warming responses of leaf litter decomposition rates in cold biomes.

    NARCIS (Netherlands)

    Cornelissen, J.H.C.; van Bodegom, P.M.; Aerts, R.; Gallaghan, T.V.; van Logtestijn, R.S.P; Alatalo, J.; Chapin, F.S. III; Gerdol, R.; Gudmundsson, J.; Gwynn-Jones, D.; Hartley, A.E.; Hik, D.S.; Hofgaard, A.; Jonsdottir, I.S.; Karlsson, S.; Klein, J.A.; Laundre, J.; Magnusson, B.; Michelsel, A.; Molau, U.; Onipchenko, V.G.; Quested, H.M.; Sandvik, S.M.; Schmidt, I.K.; Shaver, G.R.; Solhleim, B.; Soudzilovskaia, N.A.; Stenstrom, A.; Tolvanen, A.; Totland, O.; Wada, N.; Welker, J.M.; Zhao, X.; Team, M.O.L.

    2007-01-01

    Whether climate change will turn cold biomes from large long-term carbon sinks into sources is hotly debated because of the great potential for ecosystem-mediated feedbacks to global climate. Critical are the direction, magnitude and generality of climate responses of plant litter decomposition.

  12. The freezer defrosting: global warming and litter decomposition rates in cold biomes. Essay review.

    NARCIS (Netherlands)

    Aerts, R.

    2006-01-01

    1 Decomposition of plant litter, a key component of the global carbon budget, is hierarchically controlled by the triad: climate > litter quality > soil organisms. Given the sensitivity of decomposition to temperature, especially in cold biomes, it has been hypothesized that global warming will lead

  13. A reconstruction of Colombian biomes derived from modern pollen data along an altitude gradient

    NARCIS (Netherlands)

    Marchant, R.; Berrío, J.C.; Cleef, A.M.; Duivenvoorden, J.; Helmens, K.; Hooghiemstra, H.; Kuhry, P.; Melief, B.; Schreve-Brinkman, E.; Geel, van B.; Reenen, van G.; Hammen, van der T.

    2001-01-01

    Biomes are reconstructed in Colombia from modern (core-top) pollen data derived from 22 sites along an altitudinal gradient (2000–4100 m) that encompasses the tree line. The `biomization' methodology is described in a stepwise manner that details the reconstruction of vegetation along an altitudinal

  14. A reconstruction of Colombian biomes derived from modern pollen data along an altitude gradient.

    NARCIS (Netherlands)

    Marchant, R.A.; Behling, H.; Berrio Mogollon, J.C.; Cleef, A.M.; Duivenvoorden, J.F.; van Geel, B.; van der Hammen, T.; Hooghiemstra, H.; Kuhry, P.; Melief, B.M.; van Reenen, G.B.A.; Wille, M.

    2001-01-01

    Biomes are reconstructed in Colombia from modern (core-top) pollen data derived from twenty-two sites along an altitudinal gradient (2000 to 4100 m) that encompasses the tree line. The 'biomization' methodology is described in a stepwise manner that details the reconstruction of vegetation along an

  15. Incorporating grassland management in a global vegetation model

    Science.gov (United States)

    Chang, Jinfeng; Viovy, Nicolas; Vuichard, Nicolas; Ciais, Philippe; Wang, Tao; Cozic, Anne; Lardy, Romain; Graux, Anne-Isabelle; Klumpp, Katja; Martin, Raphael; Soussana, Jean-François

    2013-04-01

    Grassland is a widespread vegetation type, covering nearly one-fifth of the world's land surface (24 million km2), and playing a significant role in the global carbon (C) cycle. Most of grasslands in Europe are cultivated to feed animals, either directly by grazing or indirectly by grass harvest (cutting). A better understanding of the C fluxes from grassland ecosystems in response to climate and management requires not only field experiments but also the aid of simulation models. ORCHIDEE process-based ecosystem model designed for large-scale applications treats grasslands as being unmanaged, where C / water fluxes are only subject to atmospheric CO2 and climate changes. Our study describes how management of grasslands is included in the ORCHIDEE, and how management affects modeled grassland-atmosphere CO2 fluxes. The new model, ORCHIDEE-GM (Grassland Management) is capable with a management module inspired from a grassland model (PaSim, version 5.0), of accounting for two grassland management practices (cutting and grazing). The evaluation of the results of ORCHIDEE-GM compared with those of ORCHIDEE at 11 European sites equipped with eddy covariance and biometric measurements, show that ORCHIDEE-GM can capture realistically the cut-induced seasonal variation in biometric variables (LAI: Leaf Area Index; AGB: Aboveground Biomass) and in CO2 fluxes (GPP: Gross Primary Productivity; TER: Total Ecosystem Respiration; and NEE: Net Ecosystem Exchange). But improvements at grazing sites are only marginal in ORCHIDEE-GM, which relates to the difficulty in accounting for continuous grazing disturbance and its induced complex animal-vegetation interactions. Both NEE and GPP on monthly to annual timescales can be better simulated in ORCHIDEE-GM than in ORCHIDEE without management. At some sites, the model-observation misfit in ORCHIDEE-GM is found to be more related to ill-constrained parameter values than to model structure. Additionally, ORCHIDEE-GM is able to simulate

  16. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  17. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

    2015-03-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  18. First standardized inventory of ants (Hymenoptera: Formicidae in the natural grasslands of Paraná: New records for Southern Brazil

    Directory of Open Access Journals (Sweden)

    Weslly Franco

    2018-03-01

    Full Text Available Abstract Despite the large number of studies investigating ant diversity in Brazilian biomes, no ant-related studies have been carried out in Campos Gerais, a grassland physiognomy in Paraná state. The present study is the first inventory of the ant fauna in one of the few conservation units protecting the Campos Gerais landscape, the Guartelá State Park (PEG. Sixty samples were collected from different habitats within PEG using pitfall traps. Qualitative samples of leaf litter were collected from forest fragments and submitted to Winkler extractors. In addition, manual qualitative sampling was carried out in the various physiognomies within the PEG. A total of 163 species was collected and sorted into 43 genera and nine subfamilies. Five genera and 28 species were recorded for the first time in the state of Paraná. Out of these, 17 species were also recorded for the first time in the Southern Region of Brazil and two were recorded for the first time to the country. The significant species richness in the PEG and the high number of new records is a strong sign of this ecosystem’s potential to reveal taxonomic novelties. These results suggest that PEG, and the Campos Gerais as a whole, should be the target of greater conservation efforts to preserve native remnants.

  19. Abundance of Conepatus chinga (Carnivora, Mephitidae and other medium-sized mammals in grasslands of southern Brazil

    Directory of Open Access Journals (Sweden)

    Carlos B. Kasper

    2012-09-01

    Full Text Available Between January 2007 and December 2010, the abundance of medium-sized mammals was studied, with special focus on the Molina's hog-nosed skunk, Conepatus chinga (Molina, 1782, at four locations in southern Brazil. In this study, transect line methodology was used to obtain data for Distance Analyses. Transects were traveled by car at night, searching with spotlights along the edges of secondary roads in agricultural landscapes. Along 1,811 km, we obtained 620 observations of 20 mammal species. The most common species was the exotic European hare, Lepus europaeus (Pallas, 1778; the highest abundance estimated for South America was observed in one of the study areas, where its density was estimated as 32 individuals/km². Carnivores were the most commonly recorded mammals, represented by 10 species and comprising 51% of all observations. Molina's hog-nosed skunk occurred in all study areas, but occurred in sufficient numbers to obtain density estimates in only two of the areas. We estimated 1.4 to 3.8 individuals/km², in the first density estimate made by the transect method for a member of Conepatus in the Neotropics. These values are similar to those estimated for North American species of Mephitidae. In Brazil, C. chinga is apparently more abundant in the Pampa biome than in the grasslands of the Atlantic Forest. For two other carnivores, Lycalopex gymnocercus (Fisher, 1814 and Cerdocyon thous (Linnaeus, 1766, we estimated preliminary densities that were similar to those previously cited for different regions.

  20. Ecology and Conservation of Steppes and Semi-Natural Grasslands

    Directory of Open Access Journals (Sweden)

    Valkó Orsolya

    2016-12-01

    Full Text Available Palaearctic grasslands encompass a diverse variety of habitats, many of high nature value and vulnerability. The main challenges are climate-change, land-use change, agricultural intensification and abandonment. Many measures are in place to address these challenges, through restoration and appropriate management, though more work is necessary. We present eight studies from China/Germany, Greece, Kazakhstan, Russia and Ukraine. The papers cover a wide range of grassland and steppe habitats and cover vegetation ecology, syntaxonomy and zoology. We also conducted a systematic search on steppe and grassland diversity. The greatest number of studies was from China, followed by Germany and England. We conclude that the amount of research being carried out on Eurasian grasslands is inadequate considering their high levels of biodiversity and vulnerability. We hope to encourage readers to address current major challenges, such as how to manage grasslands for the benefit of diverse taxa, to ensure that conservation initiatives concentrate on sites where there is good potential for success and for the generation of realistic and viable conservation strategies.

  1. Classification of Grassland Successional Stages Using Airborne Hyperspectral Imagery

    Directory of Open Access Journals (Sweden)

    Thomas Möckel

    2014-08-01

    Full Text Available Plant communities differ in their species composition, and, thus, also in their functional trait composition, at different stages in the succession from arable fields to grazed grassland. We examine whether aerial hyperspectral (414–2501 nm remote sensing can be used to discriminate between grazed vegetation belonging to different grassland successional stages. Vascular plant species were recorded in 104.1 m2 plots on the island of Öland (Sweden and the functional properties of the plant species recorded in the plots were characterized in terms of the ground-cover of grasses, specific leaf area and Ellenberg indicator values. Plots were assigned to three different grassland age-classes, representing 5–15, 16–50 and >50 years of grazing management. Partial least squares discriminant analysis models were used to compare classifications based on aerial hyperspectral data with the age-class classification. The remote sensing data successfully classified the plots into age-classes: the overall classification accuracy was higher for a model based on a pre-selected set of wavebands (85%, Kappa statistic value = 0.77 than one using the full set of wavebands (77%, Kappa statistic value = 0.65. Our results show that nutrient availability and grass cover differences between grassland age-classes are detectable by spectral imaging. These techniques may potentially be used for mapping the spatial distribution of grassland habitats at different successional stages.

  2. Grassland ecology and population growth: striking a balance.

    Science.gov (United States)

    Hou, D; Duan, C; Zhang, D

    2000-06-01

    Degradation of forest and grasslands in western China attributes to the soil erosion and desertification in the country. Researchers have established that the primary reason for the degradation of grasslands is overgrazing, which in turn is caused by a number of factors, including over-population and over-reliance on animal husbandry. In addition, the existing administrative system has also proved ineffective in ensuring sustainable development. On contrary, many local governments even encourage exploitative development of grassland; thus, localities opened up grassland for growing crops in an effort to increase income. According to estimates, degraded grassland accounts for more than one-third of utilizable acreage and another one-third suffers from a profusion of rats and pests. To redress the situation, central government should implement strategies in achieving sustainable development, such as providing banking and tax incentives for the development of the secondary and tertiary industries, and supporting education and training of youths from herding areas. Moreover, government should increase spending on infrastructural construction and ecological preservation. Finally, the family planning program needs to be enforced to control population growth and improve the quality of peoples¿ lives.

  3. Pollen-based biome reconstructions for Colombia at 3000, 6000, 15 000 and 18 000 14C yr ago : Late Quaternary tropical vegetation dynamics

    NARCIS (Netherlands)

    Marchant, R.; Behling, H.; Berrío, J.C.; Cleef, A.M.; Duivenvoorden, J.; Hooghiemstra, H.; Kuhry, P.; Melief, B.; Schreve-Brinkman, E.; Geel, van B.; Hammen, van der T.; Reenen, van G.

    2002-01-01

    Colombian biomes are reconstructed at 45 sites from the modern period extending to the Last Glacial Maximum (LGM). The basis for our reconstruction is pollen data assigned to plant functional types and biomes at six 3000-yr intervals. A reconstruction of modern biomes is used to check the treatment

  4. Estimation of the Net Ecosystem Productivity in Huang-Huai Hai Region Combining with Biome-BGC Model and Remote Sensing Data%遥感数据结合Biome-BGC模型估算黄淮海地区生态系统生产力

    Institute of Scientific and Technical Information of China (English)

    胡波; 孙睿; 陈永俊; 冯丽超; 孙亮

    2011-01-01

    that the NEP and NPP were greater in the southern part of the region.The respective order of average NEP and NPP of different vegetation types was as follows: mixed forest,deciduous broadleaf forest,evergreen needleleaf forest,crop,shrub and grassland;and mixed forest,crop,deciduous broadleaf forest,evergreen needleleaf forest,shrub and grassland.Compared to the observation data,MODIS NPP product and the statistical data,we found that Biome-BGC model successfully simulated the regional vegetation productivity,and the coefficient of determination between the simulated NPP of crop and the statistical data had reached 0.6123.In addition,the simulated result of crop NPP in the Huang-Huai-Hai Region was closer to the statistical data than the MODIS NPP product.

  5. Estimating 40 years of nitrogen deposition in global biomes using the SCIAMACHY NO2 column

    Science.gov (United States)

    Lu, Xuehe; Zhang, Xiuying; Liu, Jinxun; Jin, Jiaxin

    2016-01-01

    Owing to human activity, global nitrogen (N) cycles have been altered. In the past 100 years, global N deposition has increased. Currently, the monitoring and estimating of N deposition and the evaluation of its effects on global carbon budgets are the focus of many researchers. NO2 columns retrieved by space-borne sensors provide us with a new way of exploring global N cycles and these have the ability to estimate N deposition. However, the time range limitation of NO2 columns makes the estimation of long timescale N deposition difficult. In this study we used ground-based NOx emission data to expand the density of NO2columns, and 40 years of N deposition (1970–2009) was inverted using the multivariate linear model with expanded NO2 columns. The dynamic of N deposition was examined in both global and biome scales. The results show that the average N deposition was 0.34 g N m–2 year–1 in the 2000s, which was an increase of 38.4% compared with the 1970s’. The total N deposition in different biomes is unbalanced. N deposition is only 38.0% of the global total in forest biomes; this is made up of 25.9%, 11.3, and 0.7% in tropical, temperate, and boreal forests, respectively. As N-limited biomes, there was little increase of N deposition in boreal forests. However, N deposition has increased by a total of 59.6% in tropical forests and croplands, which are N-rich biomes. Such characteristics may influence the effects on global carbon budgets.

  6. Forest carbon emissions from cropland expansion in the Brazilian Cerrado biome

    Science.gov (United States)

    Noojipady, Praveen; Morton, C. Douglas; Macedo, N. Marcia; Victoria, C. Daniel; Huang, Chengquan; Gibbs, K. Holly; Edson Bolfe, L.

    2017-02-01

    Land use, land use change, and forestry accounted for two-thirds of Brazil’s greenhouse gas emissions profile in 2005. Amazon deforestation has declined by more than 80% over the past decade, yet Brazil’s forests extend beyond the Amazon biome. Rapid expansion of cropland in the neighboring Cerrado biome has the potential to undermine climate mitigation efforts if emissions from dry forest and woodland conversion negate some of the benefits of avoided Amazon deforestation. Here, we used satellite data on cropland expansion, forest cover, and vegetation carbon stocks to estimate annual gross forest carbon emissions from cropland expansion in the Cerrado biome. Nearly half of the Cerrado met Brazil’s definition of forest cover in 2000 (≥0.5 ha with ≥10% canopy cover). In areas of established crop production, conversion of both forest and non-forest Cerrado formations for cropland declined during 2003-2013. However, forest carbon emissions from cropland expansion increased over the past decade in Matopiba, a new frontier of agricultural production that includes portions of Maranhão, Tocantins, Piauí, and Bahia states. Gross carbon emissions from cropland expansion in the Cerrado averaged 16.28 Tg C yr-1 between 2003 and 2013, with forest-to-cropland conversion accounting for 29% of emissions. The fraction of forest carbon emissions from Matopiba was much higher; between 2010-2013, large-scale cropland conversion in Matopiba contributed 45% of total Cerrado forest carbon emissions. Carbon emissions from Cerrado-to-cropland transitions offset 5%-7% of the avoided emissions from reduced Amazon deforestation rates during 2011-2013. Comprehensive national estimates of forest carbon fluxes, including all biomes, are critical to detect cross-biome leakage within countries and achieve climate mitigation targets to reduce emissions from land use, land use change, and forestry.

  7. Aura-biomes are present in the water layer above coral reef benthic macro-organisms.

    Science.gov (United States)

    Walsh, Kevin; Haggerty, J Matthew; Doane, Michael P; Hansen, John J; Morris, Megan M; Moreira, Ana Paula B; de Oliveira, Louisi; Leomil, Luciana; Garcia, Gizele D; Thompson, Fabiano; Dinsdale, Elizabeth A

    2017-01-01

    As coral reef habitats decline worldwide, some reefs are transitioning from coral- to algal-dominated benthos with the exact cause for this shift remaining elusive. Increases in the abundance of microbes in the water column has been correlated with an increase in coral disease and reduction in coral cover. Here we investigated how multiple reef organisms influence microbial communities in the surrounding water column. Our study consisted of a field assessment of microbial communities above replicate patches dominated by a single macro-organism. Metagenomes were constructed from 20 L of water above distinct macro-organisms, including (1) the coral Mussismilia braziliensis , (2) fleshy macroalgae ( Stypopodium , Dictota and Canistrocarpus ), (3) turf algae, and (4) the zoanthid Palythoa caribaeorum and were compared to the water microbes collected 3 m above the reef. Microbial genera and functional potential were annotated using MG-RAST and showed that the dominant benthic macro-organisms influence the taxa and functions of microbes in the water column surrounding them, developing a specific "aura-biome". The coral aura-biome reflected the open water column, and was associated with Synechococcus and functions suggesting oligotrophic growth, while the fleshy macroalgae aura-biome was associated with Ruegeria , Pseudomonas, and microbial functions suggesting low oxygen conditions. The turf algae aura-biome was associated with Vibrio, Flavobacterium, and functions suggesting pathogenic activity, while zoanthids were associated with Alteromonas and functions suggesting a stressful environment. Because each benthic organism has a distinct aura-biome, a change in benthic cover will change the microbial community of the water, which may lead to either the stimulation or suppression of the recruitment of benthic organisms.

  8. Forgotten forests - issues and prospects in biome mapping using Seasonally Dry Tropical Forests as a case study

    Science.gov (United States)

    2011-01-01

    Background South America is one of the most species diverse continents in the world. Within South America diversity is not distributed evenly at both local and continental scales and this has led to the recognition of various areas with unique species assemblages. Several schemes currently exist which divide the continental-level diversity into large species assemblages referred to as biomes. Here we review five currently available biome maps for South America, including the WWF Ecoregions, the Americas basemap, the Land Cover Map of South America, Morrone's Biogeographic regions of Latin America, and the Ecological Systems Map. The comparison is performed through a case study on the Seasonally Dry Tropical Forest (SDTF) biome using herbarium data of habitat specialist species. Results Current biome maps of South America perform poorly in depicting SDTF distribution. The poor performance of the maps can be attributed to two main factors: (1) poor spatial resolution, and (2) poor biome delimitation. Poor spatial resolution strongly limits the use of some of the maps in GIS applications, especially for areas with heterogeneous landscape such as the Andes. Whilst the Land Cover Map did not suffer from poor spatial resolution, it showed poor delimitation of biomes. The results highlight that delimiting structurally heterogeneous vegetation is difficult based on remote sensed data alone. A new refined working map of South American SDTF biome is proposed, derived using the Biome Distribution Modelling (BDM) approach where georeferenced herbarium data is used in conjunction with bioclimatic data. Conclusions Georeferenced specimen data play potentially an important role in biome mapping. Our study shows that herbarium data could be used as a way of ground-truthing biome maps in silico. The results also illustrate that herbarium data can be used to model vegetation maps through predictive modelling. The BDM approach is a promising new method in biome mapping, and could be

  9. Forgotten forests--issues and prospects in biome mapping using Seasonally Dry Tropical Forests as a case study.

    Science.gov (United States)

    Särkinen, Tiina; Iganci, João R V; Linares-Palomino, Reynaldo; Simon, Marcelo F; Prado, Darién E

    2011-11-24

    South America is one of the most species diverse continents in the world. Within South America diversity is not distributed evenly at both local and continental scales and this has led to the recognition of various areas with unique species assemblages. Several schemes currently exist which divide the continental-level diversity into large species assemblages referred to as biomes. Here we review five currently available biome maps for South America, including the WWF Ecoregions, the Americas basemap, the Land Cover Map of South America, Morrone's Biogeographic regions of Latin America, and the Ecological Systems Map. The comparison is performed through a case study on the Seasonally Dry Tropical Forest (SDTF) biome using herbarium data of habitat specialist species. Current biome maps of South America perform poorly in depicting SDTF distribution. The poor performance of the maps can be attributed to two main factors: (1) poor spatial resolution, and (2) poor biome delimitation. Poor spatial resolution strongly limits the use of some of the maps in GIS applications, especially for areas with heterogeneous landscape such as the Andes. Whilst the Land Cover Map did not suffer from poor spatial resolution, it showed poor delimitation of biomes. The results highlight that delimiting structurally heterogeneous vegetation is difficult based on remote sensed data alone. A new refined working map of South American SDTF biome is proposed, derived using the Biome Distribution Modelling (BDM) approach where georeferenced herbarium data is used in conjunction with bioclimatic data. Georeferenced specimen data play potentially an important role in biome mapping. Our study shows that herbarium data could be used as a way of ground-truthing biome maps in silico. The results also illustrate that herbarium data can be used to model vegetation maps through predictive modelling. The BDM approach is a promising new method in biome mapping, and could be particularly useful for mapping

  10. Forgotten forests - issues and prospects in biome mapping using Seasonally Dry Tropical Forests as a case study

    Directory of Open Access Journals (Sweden)

    Särkinen Tiina

    2011-11-01

    Full Text Available Abstract Background South America is one of the most species diverse continents in the world. Within South America diversity is not distributed evenly at both local and continental scales and this has led to the recognition of various areas with unique species assemblages. Several schemes currently exist which divide the continental-level diversity into large species assemblages referred to as biomes. Here we review five currently available biome maps for South America, including the WWF Ecoregions, the Americas basemap, the Land Cover Map of South America, Morrone's Biogeographic regions of Latin America, and the Ecological Systems Map. The comparison is performed through a case study on the Seasonally Dry Tropical Forest (SDTF biome using herbarium data of habitat specialist species. Results Current biome maps of South America perform poorly in depicting SDTF distribution. The poor performance of the maps can be attributed to two main factors: (1 poor spatial resolution, and (2 poor biome delimitation. Poor spatial resolution strongly limits the use of some of the maps in GIS applications, especially for areas with heterogeneous landscape such as the Andes. Whilst the Land Cover Map did not suffer from poor spatial resolution, it showed poor delimitation of biomes. The results highlight that delimiting structurally heterogeneous vegetation is difficult based on remote sensed data alone. A new refined working map of South American SDTF biome is proposed, derived using the Biome Distribution Modelling (BDM approach where georeferenced herbarium data is used in conjunction with bioclimatic data. Conclusions Georeferenced specimen data play potentially an important role in biome mapping. Our study shows that herbarium data could be used as a way of ground-truthing biome maps in silico. The results also illustrate that herbarium data can be used to model vegetation maps through predictive modelling. The BDM approach is a promising new method in

  11. Prescribed burning to affect a state transition in a shrub-encroached desert grassland

    Science.gov (United States)

    Prescribed burning is a commonly advocated and historical practice for control of woody species encroachment into grasslands on all continents. However, desert grasslands of the southwestern United States often lack needed herbaceous fuel loads for effective prescriptions, dominant perennial gramin...

  12. Carbon fluxes from an urban tropical grassland

    International Nuclear Information System (INIS)

    Ng, B.J.L.; Hutyra, L.R.; Nguyen, H.; Cobb, A.R.; Kai, F.M.; Harvey, C.; Gandois, L.

    2015-01-01

    Turfgrass covers a large fraction of the urbanized landscape, but the carbon exchange of urban lawns is poorly understood. We used eddy covariance and flux chambers in a grassland field manipulative experiment to quantify the carbon mass balance in a Singapore tropical turfgrass. We also assessed how management and variations in environmental factors influenced CO 2 respiration. Standing aboveground turfgrass biomass was 80 gC m −2 , with a mean ecosystem respiration of 7.9 ± 1.1 μmol m −2  s −1 . The contribution of autotrophic respiration was 49–76% of total ecosystem respiration. Both chamber and eddy covariance measurements suggest the system was in approximate carbon balance. While we did not observe a significant relationship between the respiration rates and soil temperature or moisture, daytime fluxes increased during the rainy interval, indicating strong overall moisture sensitivity. Turfgrass biomass is small, but given its abundance across the urban landscape, it significantly influences diurnal CO 2 concentrations. - Highlights: • We measured urban turfgrass CO 2 respiration rates and soil characteristics. • Mean observed ecosystem respiration was 7.9 ± 1.1 μmol m −2  s −1 . • Soil temperature and moisture were largely insignificant drivers of observed flux. - We found a Singapore urban turfgrass to be approximately carbon neutral, with a mean ecosystem respiration of 7.9 ± 1.1 μmol m −2  s −1

  13. Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands.

    Science.gov (United States)

    Loucougaray, Grégory; Dobremez, Laurent; Gos, Pierre; Pauthenet, Yves; Nettier, Baptiste; Lavorel, Sandra

    2015-11-01

    Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

  14. The Biological Observation Matrix (BIOM format or: how I learned to stop worrying and love the ome-ome

    Directory of Open Access Journals (Sweden)

    McDonald Daniel

    2012-07-01

    Full Text Available Abstract Background We present the Biological Observation Matrix (BIOM, pronounced “biome” format: a JSON-based file format for representing arbitrary observation by sample contingency tables with associated sample and observation metadata. As the number of categories of comparative omics data types (collectively, the “ome-ome” grows rapidly, a general format to represent and archive this data will facilitate the interoperability of existing bioinformatics tools and future meta-analyses. Findings The BIOM file format is supported by an independent open-source software project (the biom-format project, which initially contains Python objects that support the use and manipulation of BIOM data in Python programs, and is intended to be an open development effort where developers can submit implementations of these objects in other programming languages. Conclusions The BIOM file format and the biom-format project are steps toward reducing the “bioinformatics bottleneck” that is currently being experienced in diverse areas of biological sciences, and will help us move toward the next phase of comparative omics where basic science is translated into clinical and environmental applications. The BIOM file format is currently recognized as an Earth Microbiome Project Standard, and as a Candidate Standard by the Genomic Standards Consortium.

  15. Modeling effects of conservation grassland losses on amphibian habitat

    Science.gov (United States)

    Mushet, David M.; Neau, Jordan L.; Euliss, Ned H.

    2014-01-01

    Amphibians provide many ecosystem services valued by society. However, populations have declined globally with most declines linked to habitat change. Wetlands and surrounding terrestrial grasslands form habitat for amphibians in the North American Prairie Pothole Region (PPR). Wetland drainage and grassland conversion have destroyed or degraded much amphibian habitat in the PPR. However, conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining grasslands on agricultural lands. We used an ecosystem services model (InVEST) parameterized for the PPR to quantify amphibian habitat over a six-year period (2007–2012). We then quantified changes in availability of amphibian habitat under various land-cover scenarios representing incremental losses (10%, 25%, 50%, 75%, and 100%) of CRP grasslands from 2012 levels. The area of optimal amphibian habitat in the four PPR ecoregions modeled (i.e., Northern Glaciated Plains, Northwestern Glaciated Plains, Lake Agassiz Plain, Des Moines Lobe) declined by approximately 22%, from 3.8 million ha in 2007 to 2.9 million ha in 2012. These losses were driven by the conversion of CRP grasslands to croplands, primarily for corn and soybean production. Our modeling identified an additional 0.8 million ha (26%) of optimal amphibian habitat that would be lost if remaining CRP lands are returned to crop production. An economic climate favoring commodity production over conservation has resulted in substantial losses of amphibian habitat across the PPR that will likely continue into the future. Other regions of the world face similar challenges to maintaining amphibian habitats.

  16. Tools for Management for Grassland Ecosystem Sustainability: Thinking "Outside the Box"

    Science.gov (United States)

    Gerald J. Gottfried

    2004-01-01

    Grassland ecosystem management is dynamic and has adapted to the development of new tools and ideas. Our ancestors were indirectly managing grasslands when they learned to move livestock to take advantage of better water and greener forage. One could argue that even their hunting of grassland wildlife, especially the use of fire to drive animals to waiting hunters, had...

  17. Resilience and stability of the grasslands of the Transkei | B | African ...

    African Journals Online (AJOL)

    In spite of very high stocking rates the grasslands of Transkei still have in many areas a high cover and many climax species. The concepts of resilience and stability are used in an attempt to explain dynamics of the grasslands. Keywords: resiliences|stabilities|grasslands|Transkei|stocking rates|basal covers|grass ...

  18. Evapotranspiration and soil moisture dynamics in a temperate grassland ecosystem in Inner Mongolia China

    Science.gov (United States)

    L. Hao; Ge Sun; Yongqiang Liu; G. S. Zhou; J. H.   Wan;  L. B. Zhang; J. L. Niu; Y. H. Sang;  J. J He

    2015-01-01

    Precipitation, evapotranspiration (ET), and soil moisture are the key controls for the productivity and functioning of temperate grassland ecosystems in Inner Mongolia, northern China. Quantifying the soil moisture dynamics and water balances in the grasslands is essential to sustainable grassland management under global climate change. We...

  19. Voluntary intake and in vivo digestibility of forages from semi-natural grasslands in dairy cows

    NARCIS (Netherlands)

    Bruinenberg, M.H.; Valk, H.; Struik, P.C.

    2003-01-01

    To study in vivo digestibility of forages from semi-natural grasslands two experiments were carried out. In the first experiment lactating dairy cows were offered three different silage-based diets. Silage originated from intensively managed grassland (IM), extensively managed species-poor grassland

  20. Forest and grassland carbon in North America: A short course for land managers

    Science.gov (United States)

    Chris Swanston; Michael J. Furniss; Kristen Schmitt; Jeffrey Guntle; Maria Janowiak; Sarah Hines

    2012-01-01

    This multimedia short-course presents a range of information on the science, management and policy of forest and grassland carbon. Forests and grasslands worldwide play a critical role in storing carbon and sequestering greenhouse gases from the atmosphere. The U.S. Forest Service, which manages 193 million acres of forests and grasslands, emphasizes the need for...

  1. Future changes in South American biomass distributions, biome distributions and plant trait spectra is dependent on applied atmospheric forcings.

    Science.gov (United States)

    Langan, Liam; Scheiter, Simon; Higgins, Steven

    2017-04-01

    It remains poorly understood why the position of the forest-savanna biome boundary, in a domain defined by precipitation and temperature, differs in South America, Africa and Australia. Process based Dynamic Global Vegetation Models (DGVMs) are a valuable tool to investigate the determinants of vegetation distributions, however, many DGVMs fail to predict the spatial distribution or indeed presence of the South American savanna biome. Evidence suggests fire plays a significant role in mediating forest-savanna biome boundaries, however, fire alone appear to be insufficient to predict these boundaries in South America. We hypothesize that interactions between precipitation, constraints on tree rooting depth and fire, affect the probability of savanna occurrence and the position of the savanna-forest boundary. We tested our hypotheses at tropical forest and savanna sites in Brazil and Venezuela using a novel DGVM, aDGVM2, which allows plant trait spectra, constrained by trade-offs between traits, to evolve in response to abiotic and biotic conditions. Plant hydraulics is represented by the cohesion-tension theory, this allowed us to explore how soil and plant hydraulics control biome distributions and plant traits. The resulting community trait distributions are emergent properties of model dynamics. We showed that across much of South America the biome state is not determined by climate alone. Interactions between tree rooting depth, fire and precipitation affected the probability of observing a given biome state and the emergent traits of plant communities. Simulations where plant rooting depth varied in space provided the best match to satellite derived biomass estimates and generated biome distributions that reproduced contemporary biome maps well. Future projections showed that biomass distributions, biome distributions and plant trait spectra will change, however, the magnitude of these changes are highly dependent on the applied atmospheric forcings.

  2. Effects of haying on breeding birds in CRP grasslands

    Science.gov (United States)

    Igl, Lawrence D.; Johnson, Douglas H.

    2016-01-01

    The Conservation Reserve Program (CRP) is a voluntary program that is available to agricultural producers to help protect environmentally sensitive or highly erodible land. Management disturbances of CRP grasslands generally are not allowed unless authorized to provide relief to livestock producers during severe drought or a similar natural disaster (i.e., emergency haying and grazing) or to improve the quality and performance of the CRP cover (i.e., managed haying and grazing). Although CRP grasslands may not be hayed or grazed during the primary bird-nesting season, these disturbances may have short-term (1 yr after disturbance) and long-term (≥2 yr after disturbance) effects on grassland bird populations. We assessed the effects of haying on 20 grassland bird species in 483 CRP grasslands in 9 counties of 4 states in the northern Great Plains, USA between 1993 and 2008. We compared breeding bird densities (as determined by total-area counts) in idle and hayed fields to evaluate changes 1, 2, 3, and 4 years after haying. Haying of CRP grasslands had either positive or negative effects on grassland birds, depending on the species, the county, and the number of years after the initial disturbance. Some species (e.g., horned lark [Eremophila alpestris], bobolink [Dolichonyx oryzivorus]) responded positively after haying, and others (e.g., song sparrow [Melospiza melodia]) responded negatively. The responses of some species changed direction as the fields recovered from haying. For example, densities for common yellowthroat (Geothlypis trichas), sedge wren (Cistothorus platensis), and clay-colored sparrow (Spizella pallida) declined the first year after haying but increased in the subsequent 3 years. Ten species showed treatment × county interactions, indicating that the effects of haying varied geographically. This long-term evaluation on the effects of haying on breeding birds provides important information on the strength and direction of changes in

  3. Remote Sensing of the Urban Heat Island Effect Across Biomes in the Continental USA

    Science.gov (United States)

    Imhoff, Marc L.; Zhang, Ping; Wolfe, Robert E.; Bounoua, Lahouari

    2010-01-01

    Impervious surface area (ISA) from the Landsat TM-based NLCD 2001 dataset and land surface temperature (LST) from MODIS averaged over three annual cycles (2003-2005) are used in a spatial analysis to assess the urban heat island (UHI) skin temperature amplitude and its relationship to development intensity, size, and ecological setting for 38 of the most populous cities in the continental United States. Development intensity zones based on %ISA are defined for each urban area emanating outward from the urban core to the nonurban rural areas nearby and used to stratify sampling for land surface temperatures and NDVI. Sampling is further constrained by biome and elevation to insure objective intercomparisons between zones and between cities in different biomes permitting the definition of hierarchically ordered zones that are consistent across urban areas in different ecological setting and across scales. We find that ecological context significantly influences the amplitude of summer daytime UHI (urban-rural temperature difference) the largest (8 C average) observed for cities built in biomes dominated by temperate broadleaf and mixed forest. For all cities combined, ISA is the primary driver for increase in temperature explaining 70% of the total variance in LST. On a yearly average, urban areas are substantially warmer than the non-urban fringe by 2.9 C, except for urban areas in biomes with arid and semiarid climates. The average amplitude of the UHI is remarkably asymmetric with a 4.3 C temperature difference in summer and only 1.3 C in winter. In desert environments, the LST's response to ISA presents an uncharacteristic "U-shaped" horizontal gradient decreasing from the urban core to the outskirts of the city and then increasing again in the suburban to the rural zones. UHI's calculated for these cities point to a possible heat sink effect. These observational results show that the urban heat island amplitude both increases with city size and is seasonally

  4. Temporal and spatial heterogeneity analysis of optimal value of sensitive parameters in ecological process model: The BIOME-BGC model as an example%生态过程模型敏感参数最优取值的时空异质性分析——以BIOME-BGC模型为例

    Institute of Scientific and Technical Information of China (English)

    李一哲; 张廷龙; 刘秋雨; 李英

    2018-01-01

    The ecological process models are powerful tools for studying terrestrial ecosystem water and carbon cycle at present.However,there are many parameters for these models,and weather the reasonable values of these parameters were taken,have important impact on the models simulation results.In the past,the sensitivity and the optimization of model parameters were analyzed and discussed in many researches.But the temporal and spatial heterogeneity of the optimal parameters is less concerned.In this paper,the BIOME-BGC model was used as an example.In the evergreen broad-leaved forest,deciduous broad-leaved forest and C3 grassland,the sensitive parameters of the model were selected by constructing the sensitivity judgment index with two experimental sites selected under each vegetation type.The objective function was constructed by using the simulated annealing algorithm combined with the flux data to obtain the monthly optimal values of the sensitive parameters at each site.Then we constructed the temporal heterogeneity judgment index,the spatial heterogeneity judgment index and the temporal and spatial heterogeneity judgment index to quantitatively analyze the temporal and spatial heterogeneity of the optimal values of the model sensitive parameters.The results showed that the sensitivity of BIOME-BGC model parameters was different under different vegetation types,but the selected sensitive parameters were mostly consistent.The optimal values of the sensitive parameters of BIOME-BGC model mostly presented time-space heterogeneity to different degrees which varied with vegetation types.The sensitive parameters related to vegetation physiology and ecology had relatively little temporal and spatial heterogeneity while those related to environment and phenology had generally larger temporal and spatial heterogeneity.In addition,the temporal heterogeneity of the optimal values of the model sensitive parameters showed a significant linear correlation with the spatial

  5. Estimation of Carbon Flux of Forest Ecosystem over Qilian Mountains by BIOME-BGC Model

    Science.gov (United States)

    Yan, Min; Tian, Xin; Li, Zengyuan; Chen, Erxue; Li, Chunmei

    2014-11-01

    The gross primary production (GPP) and net ecosystem exchange (NEE) are important indicators for carbon fluxes. This study aims at evaluating the forest GPP and NEE over the Qilian Mountains using meteorological, remotely sensed and other ancillary data at large scale. To realize this, the widely used ecological-process-based model, Biome-BGC, and remote-sensing-based model, MODIS GPP algorithm, were selected for the simulation of the forest carbon fluxes. The combination of these two models was based on calibrating the Biome-BGC by the optimized MODIS GPP algorithm. The simulated GPP and NEE values were evaluated against the eddy covariance observed GPPs and NEEs, and the well agreements have been reached, with R2=0.76, 0.67 respectively.

  6. Candidatus Rickettsia andeanae, a spotted fever group agent infecting Amblyomma parvum ticks in two Brazilian biomes

    Directory of Open Access Journals (Sweden)

    Fernanda Aparecida Nieri-Bastos

    2014-04-01

    Full Text Available Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul and from horses in the Cerrado biome (state of Piauí in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63 and 66.7% (2/3 of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil.

  7. DYNAMICS OF CARBON SEQUESTRATION IN ABANDONED GRASSLANDS OF NORTHEASTERN MEXICO

    Directory of Open Access Journals (Sweden)

    José Israel Yerena Yamallel

    2014-04-01

    Full Text Available Livestock activities due to the improper handling of the load capacity, suffer from low productivity in their grasslands, which are abandoned giving rise to the appearance of species considered invasive and undesirable for producers, without knowing the qualities of these as mitigating of climate change. The objective of the present study was to estimate the carbon content in tamaulipan thornscrub and three abandoned grasslands with a time of abandonment of 10, 20 and 30 years. For the estimation of the carbon content was used a systematic sampling design, in each area were established four sampling sites of 1,600 m2. The primary scrub is the system that resulted in the largest value of carbon content of 14.25 Mg ha-1, followed by the grasslands of 30, 20 and 10 years with 8.03, 7.33 and 4.13 Mg ha-1 respectively. It was concluded that recovering the initial state of the primary scrub take many years, as can be seen in the grasslands system 30 years reaching only 56% of what it had in reserves of primary scrub.

  8. Quantitative ecological relationships in the alpine grassland of ...

    African Journals Online (AJOL)

    A survey, based on 56 000 points at 102 sampling sites in the Tsehlanyane valley of the Oxbow (Madibamatso) Dam catchment in the alpine grassland of Lesotho, indicates that the area is generally in good condition. Physiographic and floristic criteria were measured and the association between pairs of criteria statistically ...

  9. Crude protein changes on grassland along a degradation gradient ...

    African Journals Online (AJOL)

    Evapotranspiration was determined by quantifying the soil-water balance equation with the aid of runoff plots and soil-water content measurements. Crude protein ... The study shows that it is important to keep grassland in optimal condition to utilize limited soil water for sustainable plant and therefore animal production.

  10. Intensification of grassland and forage use: driving forces and constraints

    NARCIS (Netherlands)

    Oenema, O.; Klein, de C.; Alfaro, M.

    2014-01-01

    The increasing demand for safe and nutritional dairy and beef products in a globalising world, together with the needs to increase resource use efficiency and to protect biodiversity, provide strong incentives for intensification of grassland and forage use. This paper addresses the question: 'Does

  11. Achieving grassland production and quality that matches animal needs

    NARCIS (Netherlands)

    Pol, van den A.; Busqué, Juan; Golinski, P.; Noorkõiv, Katrin; O'Donovan, Michael; Peratoner, Giovanni; Reheul, D.

    2016-01-01

    Permanent grasslands are exploited by grazing animals or as meadows depending on different
    constraints. Grazing is the most common use in large parts of Europe, especially in the northwest of
    Europe. However, certain areas are less suitable for grazing. In the Alps e.g. meadows are the

  12. Achieving grassland production and quality that matching animal needs

    NARCIS (Netherlands)

    Pol, van den A.; Busqué, Juan; Golinski, P.; Noorkõiv, Katrin; O'Donovan, Michael; Peratoner, Giovanni; Reheul, D.

    2016-01-01

    Permanent grasslands are exploited by grazing animals or as meadows depending on different constraints. Grazing is the most common use in large parts of Europe, especially in the northwest of Europe. However, certain areas are less suitable for grazing. In the Alps e.g. meadows are the most relevant

  13. Avian diversity in the Naliya Grassland, Abdasa Taluka, Kachchh, India

    Directory of Open Access Journals (Sweden)

    Sandeep B Munjpara

    2012-03-01

    Full Text Available Naliya Grassland is one of the significant grasslands of Gujarat. In this study the importance of the Naliya Grassland has been explored with special reference to avian diversity. Field work for the study was carried out throughout the year of 2007 on a monthly basis covering three distinct seasons to explore avian diversity. A total of 177 species belonging to 54 families were recorded wherein most species belonged to the family Accipitridae (20 species followed by Alaudidae (11 species. Of the total families, five were represented by more than seven species, 18 families by 3-7 species and 31 families by one or two species respectively. Among the species observed, 16 species ware globally threatened (three Critically Endangered, four Endangered and nine Near Threatened. Most of the species were chiefly terrestrial (68.2%, about 23.9% species were freshwater dependant and 7.9% utilized mixed habitats. Maximum species richness was recorded in the monsoons and minimum in summer. Constant turnover and fluctuation in species richness occurred because of seasonal immigration and emigration. Maximum emigration took place during February and March and maximum immigration occurred during June and July. Many water dependant birds attracted to the flooded grassland during the monsoons explained the high species richness during this season. In winter, the area was inhabited by resident species as well as many migratory species.

  14. Evaluation of SPOT imagery for the estimation of grassland biomass

    Science.gov (United States)

    Dusseux, P.; Hubert-Moy, L.; Corpetti, T.; Vertès, F.

    2015-06-01

    In many regions, a decrease in grasslands and change in their management, which are associated with agricultural intensification, have been observed in the last half-century. Such changes in agricultural practices have caused negative environmental effects that include water pollution, soil degradation and biodiversity loss. Moreover, climate-driven changes in grassland productivity could have serious consequences for the profitability of agriculture. The aim of this study was to assess the ability of remotely sensed data with high spatial resolution to estimate grassland biomass in agricultural areas. A vegetation index, namely the Normalized Difference Vegetation Index (NDVI), and two biophysical variables, the Leaf Area Index (LAI) and the fraction of Vegetation Cover (fCOVER) were computed using five SPOT images acquired during the growing season. In parallel, ground-based information on grassland growth was collected to calculate biomass values. The analysis of the relationship between the variables derived from the remotely sensed data and the biomass observed in the field shows that LAI outperforms NDVI and fCOVER to estimate biomass (R2 values of 0.68 against 0.30 and 0.50, respectively). The squared Pearson correlation coefficient between observed and estimated biomass using LAI derived from SPOT images reached 0.73. Biomass maps generated from remotely sensed data were then used to estimate grass reserves at the farm scale in the perspective of operational monitoring and forecasting.

  15. Homogenization of the soil surface following fire in semiarid grasslands

    Science.gov (United States)

    Carleton S. White

    2011-01-01

    Semiarid grasslands accumulate soil beneath plant "islands" that are raised above bare interspaces. This fine-scale variation in microtopographic relief is plant-induced and is increased with shrub establishment. Research found that fire-induced water repellency enhanced local-scale soil erosion that reduced variation in microtopographic relief, suggesting...

  16. Relationship between soil chemical factors and grassland diversity

    NARCIS (Netherlands)

    Janssens, F; Peeters, A; Tallowin, JRB; Bakker, JP; Bekker, RM; Fillat, F; Oomes, MJM

    Many studies carried out during these last few years have focused on the factors influencing plant diversity in species-rich grasslands. This is due to the fact that these ecosystems, among the most diversified in temperate climates, are extremely threatened; in some areas, they have almost

  17. Transformation of a savanna grassland by drought and grazing | O ...

    African Journals Online (AJOL)

    The relative effects of drought and heavy grazing on the floristic composition, population size and and structure, and basal cover of an African savanna grassland were differentiated by comparing changes over eight years over eight years, which included a severe drought year, across a gradient of grazing history. Drought ...

  18. Controlling nitrous oxide emissions from grassland livestock production systems

    NARCIS (Netherlands)

    Oenema, O.; Gebauer, G.; Rodriguez, M.; Sapek, A.; Jarvis, S.C.; Corré, W.J.; Yamulki, S.

    1998-01-01

    There is growing awareness that grassland livestock production systems are major sources of nitrous oxide (N2O). Controlling these emissions requires a thorough understanding of all sources and controlling factors at the farm level. This paper examines the various controlling factors and proposes

  19. Effects of large herbivores on grassland arthropod diversity

    NARCIS (Netherlands)

    van Klink, R.; van der Plas, F.; van Noordwijk, C. G. E. (Toos); WallisDeVries, M. F.; Olff, H.

    Both arthropods and large grazing herbivores are important components and drivers of biodiversity in grassland ecosystems, but a synthesis of how arthropod diversity is affected by large herbivores has been largely missing. To fill this gap, we conducted a literature search, which yielded 141

  20. Potassium cycling and losses in grassland systems : a review

    NARCIS (Netherlands)

    Kayser, M; Isselstein, J

    Cycling of potassium in grassland systems has received relatively little attention in research and practice in recent years. Balanced nutrient systems require consideration of nutrients other than nitrogen (N). Potassium (K) is needed in large amounts and is closely related to N nutrition. In

  1. The effect of grassland management on enchytraeids (Oligochaeta) communities

    DEFF Research Database (Denmark)

    Maraldo, Kristine; Schmelz, Rüdiger; Christensen, Bent Tolstrup

    2012-01-01

    Enchytraeids (small white earthworms between 3 to 35 mm) are important regulators of nitrogen turnover in grasslands, as their activities accelerate the decomposition and nutrient recycling processes. In this study, the effect of management on species composition, abundance and biomass of the enc...... biomass and density of the grazed plots are due to compaction by grazing animals....

  2. Effect of burn area on invertebrate recolonization in grasslands in ...

    African Journals Online (AJOL)

    Our study examined the short-term response of grassland invertebrate communities to fire in the South African Drakensberg, in relation to distance from the edge of a burn. We aimed to establish which species survive fire and the dynamics of the post-fire recolonization process, and thereby contribute to establishing the ...

  3. Organic matter dynamics and N mineralization in grassland soils

    NARCIS (Netherlands)

    Hassink, J.

    1995-01-01


    The aims of this study are i) to improve our understanding of the interactions between soil texturelsoil structure, soil organic matter, soil biota and mineralization in grassland soils, ii) to develop a procedure that yields soil organic matter fractions that can be determined directly

  4. Vegetation diversity of salt-rich grasslands in Southeast Europe

    Czech Academy of Sciences Publication Activity Database

    Eliáš, P. Jr.; Sopotlieva, D.; Dítě, D.; Hájková, Petra; Apostolova, I.; Senko, D.; Melečková, Z.; Hájek, Michal

    2013-01-01

    Roč. 16, č. 3 (2013), s. 521-537 ISSN 1402-2001 R&D Projects: GA ČR GA206/09/0329 Institutional research plan: CEZ:AV0Z60050516 Institutional support: RVO:67985939 Keywords : salt marshes * vegetation survey * grasslands Subject RIV: EF - Botanics Impact factor: 2.416, year: 2013

  5. The Economics of Root Distributions of Terrestrial Biomes in Response to Elevated CO2

    Science.gov (United States)

    Lu, M.; Hedin, L. O. O.

    2017-12-01

    Belowground root distributions of terrestrial biomes are central to understanding soil biogeochemical processes and land carbon sink. Yet models are thus far not able to predict root distributions across plant functional groups and major biomes, limiting our ability to predict the response of land systems to elevated CO2 concentration. Of particular concern is the apparent lack of stimulation of the aboveground carbon sink despite 30% increase of atmospheric CO2 over the past half-century, and despite the clear acceleration of the land carbon sink over the same period. This apparent discrepancy in land ecosystem response has led to the proposition that changes in belowground root dynamics might be responsible for the overlooked land sink. We here present a new modeling approach for predicting the response of root biomass and soil carbon storage to increased CO2. Our approach considers the first-principle mechanisms and tradeoffs by which plants and plant roots invest carbon to gain belowground resources, in collaboration with distinct root symbioses. We allow plants to locally compete for nutrients, with the ability to allocate biomass at different depths in the soil profile. We parameterized our model using an unprecedented global dataset of root traits, and validated our biome-level predictions with a recently updated global root biomass database. Our results support the idea that plants "dig deeper" when exposed to increased CO2, and we offer an economic-based mechanism for predicting the plant root response across soil conditions, plant functional groups and major biomes. Our model also recreates the observed responses across a range of free-air CO2 enrichment experiments, including a distinct response between plants associated with ectomycorrhizal and arbuscular mycorrhizal fungi. Most broadly, our findings suggest that roots may be increasingly important in the land carbon sink, and call for a greater effort to quantify belowground responses to elevated

  6. A hierarchical analysis of terrestrial ecosystem model Biome-BGC: Equilibrium analysis and model calibration

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Peter E [ORNL; Wang, Weile [ORNL; Law, Beverly E. [Oregon State University; Nemani, Ramakrishna R [NASA Ames Research Center

    2009-01-01

    The increasing complexity of ecosystem models represents a major difficulty in tuning model parameters and analyzing simulated results. To address this problem, this study develops a hierarchical scheme that simplifies the Biome-BGC model into three functionally cascaded tiers and analyzes them sequentially. The first-tier model focuses on leaf-level ecophysiological processes; it simulates evapotranspiration and photosynthesis with prescribed leaf area index (LAI). The restriction on LAI is then lifted in the following two model tiers, which analyze how carbon and nitrogen is cycled at the whole-plant level (the second tier) and in all litter/soil pools (the third tier) to dynamically support the prescribed canopy. In particular, this study analyzes the steady state of these two model tiers by a set of equilibrium equations that are derived from Biome-BGC algorithms and are based on the principle of mass balance. Instead of spinning-up the model for thousands of climate years, these equations are able to estimate carbon/nitrogen stocks and fluxes of the target (steady-state) ecosystem directly from the results obtained by the first-tier model. The model hierarchy is examined with model experiments at four AmeriFlux sites. The results indicate that the proposed scheme can effectively calibrate Biome-BGC to simulate observed fluxes of evapotranspiration and photosynthesis; and the carbon/nitrogen stocks estimated by the equilibrium analysis approach are highly consistent with the results of model simulations. Therefore, the scheme developed in this study may serve as a practical guide to calibrate/analyze Biome-BGC; it also provides an efficient way to solve the problem of model spin-up, especially for applications over large regions. The same methodology may help analyze other similar ecosystem models as well.

  7. Ecological consequences of the expansion of N2-fixing plants in cold biomes

    Science.gov (United States)

    Hiltbrunner, Erika; Aerts, Rien; Bühlmann, Tobias; Huss-Danell, Kerstin; Magnusson, Borgthor; Myrold, David D.; Reed, Sasha C.; Sigurdsson, Bjarni D.; Körner, Christian

    2014-01-01

    Research in warm-climate biomes has shown that invasion by symbiotic dinitrogen (N2)-fixing plants can transform ecosystems in ways analogous to the transformations observed as a consequence of anthropogenic, atmospheric nitrogen (N) deposition: declines in biodiversity, soil acidification, and alterations to carbon and nutrient cycling, including increased N losses through nitrate leaching and emissions of the powerful greenhouse gas nitrous oxide (N2O). Here, we used literature review and case study approaches to assess the evidence for similar transformations in cold-climate ecosystems of the boreal, subarctic and upper montane-temperate life zones. Our assessment focuses on the plant genera Lupinus and Alnus, which have become invasive largely as a consequence of deliberate introductions and/or reduced land management. These cold biomes are commonly located in remote areas with low anthropogenic N inputs, and the environmental impacts of N2-fixer invasion appear to be as severe as those from anthropogenic N deposition in highly N polluted areas. Hence, inputs of N from N2 fixation can affect ecosystems as dramatically or even more strongly than N inputs from atmospheric deposition, and biomes in cold climates represent no exception with regard to the risk of being invaded by N2-fixing species. In particular, the cold biomes studied here show both a strong potential to be transformed by N2-fixing plants and a rapid subsequent saturation in the ecosystem’s capacity to retain N. Therefore, analogous to increases in N deposition, N2-fixing plant invasions must be deemed significant threats to biodiversity and to environmental quality.

  8. Reply: “Use of BIOME-BGC to simulate Mediterranean forest carbon stocks”

    OpenAIRE

    Maselli F; Salvati R; Barbati A; Chirici G; Chiesi M

    2011-01-01

    The current note responds to the critical contribution of Dr. Eastaugh on Chiesi et al. (Chiesi et al. 2011). That paper did not aim at applying BIOME-BGC to simulate stand growth, which requires a thorough modification of the model functions. In contrast, only a parameter setting was changed in order to adjust the predicted carbon storages during the simulation of quasi-equilibrium conditions. The adjustment was calibrated on volume statistics derived from the Tuscany forest inventory and is...

  9. Record of the Buff-fronted Owl (Aegolius harrisii in the Pampa Biome, southern Brazil

    Directory of Open Access Journals (Sweden)

    Marluci Müller Rebelato

    2011-02-01

    Full Text Available We present the second record of the Buff-fronted Owl (Aegolius harrisii in the Pampa Biome, South Brazil. On 17 January 2010 an adult male was found dead at the roadside along the BR-290, São Gabriel municipality, center-east of Rio Grande do Sul state. The specimen probably collided with a car when using the area for foraging. The record reported here agrees with the suggestion that A. harrisii can use disturbed and open areas.

  10. Software quality assurance and software safety in the Biomed Control System

    International Nuclear Information System (INIS)

    Singh, R.P.; Chu, W.T.; Ludewigt, B.A.; Marks, K.M.; Nyman, M.A.; Renner, T.R.; Stradtner, R.

    1989-01-01

    The Biomed Control System is a hardware/software system used for the delivery, measurement and monitoring of heavy-ion beams in the patient treatment and biology experiment rooms in the Bevalac at the Lawrence Berkeley Laboratory (LBL). This paper describes some aspects of this system including historical background philosophy, configuration management, hardware features that facilitate software testing, software testing procedures, the release of new software quality assurance, safety and operator monitoring. 3 refs

  11. Aura-biomes are present in the water layer above coral reef benthic macro-organisms

    Directory of Open Access Journals (Sweden)

    Kevin Walsh

    2017-08-01

    Full Text Available As coral reef habitats decline worldwide, some reefs are transitioning from coral- to algal-dominated benthos with the exact cause for this shift remaining elusive. Increases in the abundance of microbes in the water column has been correlated with an increase in coral disease and reduction in coral cover. Here we investigated how multiple reef organisms influence microbial communities in the surrounding water column. Our study consisted of a field assessment of microbial communities above replicate patches dominated by a single macro-organism. Metagenomes were constructed from 20 L of water above distinct macro-organisms, including (1 the coral Mussismilia braziliensis, (2 fleshy macroalgae (Stypopodium, Dictota and Canistrocarpus, (3 turf algae, and (4 the zoanthid Palythoa caribaeorum and were compared to the water microbes collected 3 m above the reef. Microbial genera and functional potential were annotated using MG-RAST and showed that the dominant benthic macro-organisms influence the taxa and functions of microbes in the water column surrounding them, developing a specific “aura-biome”. The coral aura-biome reflected the open water column, and was associated with Synechococcus and functions suggesting oligotrophic growth, while the fleshy macroalgae aura-biome was associated with Ruegeria, Pseudomonas, and microbial functions suggesting low oxygen conditions. The turf algae aura-biome was associated with Vibrio, Flavobacterium, and functions suggesting pathogenic activity, while zoanthids were associated with Alteromonas and functions suggesting a stressful environment. Because each benthic organism has a distinct aura-biome, a change in benthic cover will change the microbial community of the water, which may lead to either the stimulation or suppression of the recruitment of benthic organisms.

  12. Genetic diversity of bats coronaviruses in the Atlantic Forest hotspot biome, Brazil.

    Science.gov (United States)

    Góes, Luiz Gustavo Bentim; Campos, Angélica Cristine de Almeida; Carvalho, Cristiano de; Ambar, Guilherme; Queiroz, Luzia Helena; Cruz-Neto, Ariovaldo Pereira; Munir, Muhammad; Durigon, Edison Luiz

    2016-10-01

    Bats are notorious reservoirs of genetically-diverse and high-profile pathogens, and are playing crucial roles in the emergence and re-emergence of viruses, both in human and in animals. In this report, we identified and characterized previously unknown and diverse genetic clusters of bat coronaviruses in the Atlantic Forest Biome, Brazil. These results highlight the virus richness of bats and their possible roles in the public health. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. 放牧对新疆草地生态系统碳源/汇的影响模拟研究%Modeling the grazing effect of grassland on the carbon source/sink in Xinjiang

    Institute of Scientific and Technical Information of China (English)

    韩其飞; 罗格平; 李超凡; 黄晓东

    2017-01-01

    Identifying the carbon source/sink strength of grassland ecosystems in Xinjiang is of great importance for the regional carbon cycle.Using the modified Biome-BGC grazing model,we modeled carbon dynamics in grasslands in Xinjiang,northwest China with varying grazing intensities.In general,the regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source,with a value of 0.38 Pg during the period 1979-2007,of which 0.37 Pg was caused by grazing.In general,the strength of carbon sequestration improved when grazing intensity was less than 0.24 head/hm2.However,the over-compensation effect may also be the result of the growth of poisonous grass.Therefore,in the future,by adding the "vegetation succession" module,we should improve the Biome-BGC grazing model to study the compensation effect more intensively.Our findings have implications for grassland ecosystem management as they relate to carbon sequestration and climate change mitigation,e.g.,removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales.We anticipate that our study will emphasize the need for large-scale assessments of how grazing affects carbon cycling.%正确评估新疆草地生态系统碳源/汇效应,对区域尺度碳循环研究具有重要意义.放牧是新疆草地生态系统中主要的人类活动,但放牧对草地碳平衡与碳动态的影响还具有很大的不确定性.利用生态系统放牧模型Biome-BGC grazing,通过情景模拟综合评价新疆草地生态系统碳源/汇的动态.结果表明:1)1979-2007年新疆草地生态系统的碳源总量为0.38PgC,其中由放牧导致的碳释放为0.37PgC;2)当平均放牧率小于0.24头标准羊/hm2时,放牧能够促进草地碳固定.研究实现了Biome-BGC grazing模型在区域尺度的应用,研究结果将有助于理解气候变化及放牧对干旱区草地生态系统碳动态变化的驱动机理,对探

  14. Federal Conservation Units in Brazil: The Situation of Biomes and Regions

    Directory of Open Access Journals (Sweden)

    Eduardo Pacca Luna Mattar

    2018-03-01

    Full Text Available ABSTRACT Federal conservation units (FCU are areas legally established by the government, in order to meet the needs of protection and sustainable exploitation of biodiversity. A way to ensure the efficiency of public management is to systematize data. Therefore, the present study grouped and analyzed public data about FCU. Brazil has 309 federal conservation units, which represent 9.06% of the national territory and 45305 residents households. The Northern Region covers 84.80% of these families and 79.20% of its area belongs to FCU. The Amazônia biome has 14.57% of its territory occupied by FCU; on the other hand, Pantanal has only 0.98% of its area protected. There is a higher concentration of public agents in the FCU of the Southeastern region and in the Mata Atlântica biome. The analysis of this information reveals significant differences between the biomes and the federation units, a fact that reflects the importance of the organization of public data.

  15. Convergence in the temperature response of leaf respiration across biomes and plant functional types.

    Science.gov (United States)

    Heskel, Mary A; O'Sullivan, Odhran S; Reich, Peter B; Tjoelker, Mark G; Weerasinghe, Lasantha K; Penillard, Aurore; Egerton, John J G; Creek, Danielle; Bloomfield, Keith J; Xiang, Jen; Sinca, Felipe; Stangl, Zsofia R; Martinez-de la Torre, Alberto; Griffin, Kevin L; Huntingford, Chris; Hurry, Vaughan; Meir, Patrick; Turnbull, Matthew H; Atkin, Owen K

    2016-04-05

    Plant respiration constitutes a massive carbon flux to the atmosphere, and a major control on the evolution of the global carbon cycle. It therefore has the potential to modulate levels of climate change due to the human burning of fossil fuels. Neither current physiological nor terrestrial biosphere models adequately describe its short-term temperature response, and even minor differences in the shape of the response curve can significantly impact estimates of ecosystem carbon release and/or storage. Given this, it is critical to establish whether there are predictable patterns in the shape of the respiration-temperature response curve, and thus in the intrinsic temperature sensitivity of respiration across the globe. Analyzing measurements in a comprehensive database for 231 species spanning 7 biomes, we demonstrate that temperature-dependent increases in leaf respiration do not follow a commonly used exponential function. Instead, we find a decelerating function as leaves warm, reflecting a declining sensitivity to higher temperatures that is remarkably uniform across all biomes and plant functional types. Such convergence in the temperature sensitivity of leaf respiration suggests that there are universally applicable controls on the temperature response of plant energy metabolism, such that a single new function can predict the temperature dependence of leaf respiration for global vegetation. This simple function enables straightforward description of plant respiration in the land-surface components of coupled earth system models. Our cross-biome analyses shows significant implications for such fluxes in cold climates, generally projecting lower values compared with previous estimates.

  16. Seasonal patterns of horse fly richness and abundance in the Pampa biome of southern Brazil.

    Science.gov (United States)

    Krüger, Rodrigo Ferreira; Krolow, Tiago Kütter

    2015-12-01

    Fluctuations in seasonal patterns of horse fly populations were examined in rainforests of tropical South America, where the climate is seasonal. These patterns were evaluated with robust analytical models rather than identifying the main factors that influenced the fluctuations. We examined the seasonality of populations of horse flies in fields and lowland areas of the Pampa biome of southern Brazil with generalized linear models. We also investigated the diversity of these flies and the sampling effort of Malaise traps in this biome over two years. All of the 29 species had clear seasonality with regard to occurrence and abundance, but only seven species were identified as being influenced by temperature and humidity. The sampling was sufficient and the estimated diversity was 10% more than observed. Seasonal trends were synchronized across species and the populations were most abundant between September and March and nearly zero in other months. While previous studies demonstrated that seasonal patterns in population fluctuations are correlated with climatic conditions in horse fly assemblages in South America rainforests, we show a clear effect of each factor on richness and abundance and the seasonality in the prevalence of horse fly assemblages in localities of the Pampa biome. © 2015 The Society for Vector Ecology.

  17. Plant phylogeny as a window on the evolution of hyperdiversity in the tropical rainforest biome.

    Science.gov (United States)

    Eiserhardt, Wolf L; Couvreur, Thomas L P; Baker, William J

    2017-06-01

    I. II. III. IV. V. VI. VII. VIII. IX. References SUMMARY: Tropical rainforest (TRF) is the most species-rich terrestrial biome on Earth, harbouring just under half of the world's plant species in c. 7% of the land surface. Phylogenetic trees provide important insights into mechanisms underpinning TRF hyperdiversity that are complementary to those obtained from the fossil record. Phylogenetic studies of TRF plant diversity have mainly focused on whether this biome is an evolutionary 'cradle' or 'museum', emphasizing speciation and extinction rates. However, other explanations, such as biome age, immigration and ecological limits, must also be considered. We present a conceptual framework for addressing the drivers of TRF diversity, and review plant studies that have tested them with phylogenetic data. Although surprisingly few in number, these studies point to old age of TRF, low extinction and high speciation rates as credible drivers of TRF hyperdiversity. There is less evidence for immigration and ecological limits, but these cannot be dismissed owing to the limited number of studies. Rapid methodological developments in DNA sequencing, macroevolutionary analysis and the integration of phylogenetics with other disciplines may improve our grasp of TRF hyperdiversity in the future. However, such advances are critically dependent on fundamental systematic research, yielding numerous, additional, well-sampled phylogenies of TRF lineages. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  18. Reimplementation of the Biome-BGC model to simulate successional change.

    Science.gov (United States)

    Bond-Lamberty, Ben; Gower, Stith T; Ahl, Douglas E; Thornton, Peter E

    2005-04-01

    Biogeochemical process models are increasingly employed to simulate current and future forest dynamics, but most simulate only a single canopy type. This limitation means that mixed stands, canopy succession and understory dynamics cannot be modeled, severe handicaps in many forests. The goals of this study were to develop a version of Biome-BGC that supported multiple, interacting vegetation types, and to assess its performance and limitations by comparing modeled results to published data from a 150-year boreal black spruce (Picea mariana (Mill.) BSP) chronosequence in northern Manitoba, Canada. Model data structures and logic were modified to support an arbitrary number of interacting vegetation types; an explicit height calculation was necessary to prioritize radiation and precipitation interception. Two vegetation types, evergreen needle-leaf and deciduous broadleaf, were modeled based on site-specific meteorological and physiological data. The new version of Biome-BGC reliably simulated observed changes in leaf area, net primary production and carbon stocks, and should be useful for modeling the dynamics of mixed-species stands and ecological succession. We discuss the strengths and limitations of Biome-BGC for this application, and note areas in which further work is necessary for reliable simulation of boreal biogeochemical cycling at a landscape scale.

  19. Development of the BIOME-BGC model for the simulation of managed Moso bamboo forest ecosystems.

    Science.gov (United States)

    Mao, Fangjie; Li, Pingheng; Zhou, Guomo; Du, Huaqiang; Xu, Xiaojun; Shi, Yongjun; Mo, Lufeng; Zhou, Yufeng; Tu, Guoqing

    2016-05-01

    Numerical models are the most appropriate instrument for the analysis of the carbon balance of terrestrial ecosystems and their interactions with changing environmental conditions. The process-based model BIOME-BGC is widely used in simulation of carbon balance within vegetation, litter and soil of unmanaged ecosystems. For Moso bamboo forests, however, simulations with BIOME-BGC are inaccurate in terms of the growing season and the carbon allocation, due to the oversimplified representation of phenology. Our aim was to improve the applicability of BIOME-BGC for managed Moso bamboo forest ecosystem by implementing several new modules, including phenology, carbon allocation, and management. Instead of the simple phenology and carbon allocation representations in the original version, a periodic Moso bamboo phenology and carbon allocation module was implemented, which can handle the processes of Moso bamboo shooting and high growth during "on-year" and "off-year". Four management modules (digging bamboo shoots, selective cutting, obtruncation, fertilization) were integrated in order to quantify the functioning of managed ecosystems. The improved model was calibrated and validated using eddy covariance measurement data collected at a managed Moso bamboo forest site (Anji) during 2011-2013 years. As a result of these developments and calibrations, the performance of the model was substantially improved. Regarding the measured and modeled fluxes (gross primary production, total ecosystem respiration, net ecosystem exchange), relative errors were decreased by 42.23%, 103.02% and 18.67%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Beyond the climate envelope: using trait filtering models to predict biome boundaries from plant physiology.

    Science.gov (United States)

    Fisher, R.; Hoffmann, W. A.; Muszala, S.

    2014-12-01

    The introduction of second-generation dynamic vegetation models - which simulate the distribution of light resources between plant types along the vertical canopy profile, and therefore facilitate the representation of plant competition explicitly - is a large increase in the complexity and fidelity with which the terrestrial biosphere is abstracted into Earth System Models. In this new class of model, biome boundaries are predicted as the emergent properties of plant physiology, and are therefore sensitive to the high-dimensional parameterizations of plant functional traits. These new approaches offer the facility to quantitatively test ecophysiological hypotheses of plant distribution at large scales, a field which remains surprisingly under-developed. Here we describe experiments conducted with the Community Land Model Ecosystem Demography component, CLM(ED), in which we reduce the complexity of the problem by testing how individual plant functional trait changes to control the location of biome boundaries between functional types. Specifically, we investigate which physiological trade-offs determine the boundary between frequently burned savanna and forest biomes, and attempt to distinguish how each strategic life-history trade-off (carbon storage, bark investment, re-sprouting strategy) contributes towards the maintenance of sharp geographical gradients between fire adapted and typically inflammable closed canopy ecosystems. This study forms part of the planning for a model-inspired fire manipulation experiment at the cerrado-forest boundary in South-Eastern Brazil, and the results will be used to guide future data-collection and analysis strategies.

  1. ANTIBACTERIAL POTENTIAL OF NATIVE PLANTS FROM THE CAATINGA BIOME AGAINST Staphylococcus spp. ISOLATES FROM SMALL RUMINANTS WITH MASTITIS

    OpenAIRE

    PEIXOTO, RODOLFO DE MORAES; SILVA, WELLINGTON ERASMO LIMA E; ALMEIDA, JACKSON ROBERTO GUEDES SILVA; BRANCO, ALEXSANDRO; COSTA, MATEUS MATIUZZI DA

    2016-01-01

    ABSTRACT The aim of the present study is to assess the antibacterial potential of plants from the Caatinga biome of the semi-arid region of Pernambuco, against Staphylococcus spp. isolates from cases of subclinical mastitis in small ruminants, such as goats and ewes. Ethanolic extracts of the following plants from the Caatinga biome were used: Encholirium spectabile Mart., Bromelia laciniosa Mart., Neoglaziovia variegata Mez., Amburana cearensis (Fr. Allem.) A. C. Smith, Hymenaea martiana Hay...

  2. Modelling the carbon budget of intensive forest monitoring sites in Germany using the simulation model BIOME-BGC

    OpenAIRE

    Jochheim, H.; Puhlmann, M.; Beese, F.; Berthold, D.; Einert, P.; Kallweit, R.; Konopatzky, A.; Meesenburg, H.; Meiwes, K.-J.; Raspe, S.; Schulte-Bisping, H.; Schulz, C.

    2008-01-01

    It is shown that by calibrating the simulation model BIOME-BGC with mandatory and optional Level II data, within the ICP Forest programme, a well-founded calculation of the carbon budget of forest stands is achievable and, based on succeeded calibration, the modified BIOME-BGC model is a useful tool to assess the effect of climate change on forest ecosystems. peerReviewed

  3. Managed grassland alters soil N dynamics and N2O emissions in temperate steppe.

    Science.gov (United States)

    Xu, Lijun; Xu, Xingliang; Tang, Xuejuan; Xin, Xiaoping; Ye, Liming; Yang, Guixia; Tang, Huajun; Lv, Shijie; Xu, Dawei; Zhang, Zhao

    2018-04-01

    Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen (N) dynamics and nitrous oxide (N 2 O) emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N2O emissions by field experiments in Hulunber in northern China. Soil (0-10cm), nitrate (NO 3 - ), ammonium (NH 4 + ), and microbial N were measured in plots in a temperate steppe (Leymus chinensis grassland) and two managed grasslands (Medicago sativa and Bromus inermis grasslands) in 2011 and 2012. The results showed conversion of L. chinensis grassland to M. sativa or B. inermis grasslands decreased concentrations of NO 3 - -N, but did not change NH 4 + -N. Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to M. sativa, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa (i.e., a legume grass) increased N 2 O emissions by 26.2%, while the conversion to the B. inermis (i.e., a non-legume grass) reduced N 2 O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO 3 - -N and NH 4 + -N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N 2 O emissions. Copyright © 2017. Published by Elsevier B.V.

  4. Evolutionary history of a keystone pollinator parallels the biome occupancy of angiosperms in the Greater Cape Floristic Region.

    Science.gov (United States)

    de Jager, Marinus L; Ellis, Allan G

    2017-02-01

    The Greater Cape Floristic Region (GCFR) in South Africa has been extensively investigated for its phenomenal angiosperm diversity. A key emergent pattern is the occurrence of older plant lineages in the southern Fynbos biome and younger lineages in the northern Succulent Karoo biome. We know practically nothing, however, about the evolutionary history of the animals that pollinate this often highly-specialized flora. In this study, we explore the evolutionary history of an important GCFR fly pollinator, Megapalpus capensis, and ask whether it exhibits broadly congruent genetic structuring and timing of diversification to flowering plants within these biomes. We find that the oldest M. capensis lineages originated in Fynbos during the Miocene, while younger Succulent Karoo lineages diverged in the Pliocene and correspond to the proposed age of this recent biome. A strong signature of population expansion is also recovered for flies in this arid biome, consistent with recent colonization. Our first investigation into the evolutionary history of GCFR pollinators thus supports a recent origin of the SK biome, as inferred from angiosperm phylogenies, and suggests that plants and pollinators may have co-diverged within this remarkable area. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years

    Science.gov (United States)

    Marchant, R.; Harrison, S.P.; Hooghiemstra, H.; Markgraf, Vera; Van Boxel, J. H.; Ager, T.; Almeida, L.; Anderson, R.; Baied, C.; Behling, H.; Berrio, J.C.; Burbridge, R.; Bjorck, S.; Byrne, R.; Bush, M.B.; Cleef, A.M.; Duivenvoorden, J.F.; Flenley, J.R.; De Oliveira, P.; Van Geel, B.; Graf, K.J.; Gosling, W.D.; Harbele, S.; Van Der Hammen, T.; Hansen, B.C.S.; Horn, S.P.; Islebe, G.A.; Kuhry, P.; Ledru, M.-P.; Mayle, F.E.; Leyden, B.W.; Lozano-Garcia, S.; Melief, A.B.M.; Moreno, P.; Moar, N.T.; Prieto, A.; Van Reenen, G. B.; Salgado-Labouriau, M. L.; Schasignbitz, F.; Schreve-Brinkman, E. J.; Wille, M.

    2009-01-01

    The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation. At 6000±500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000±500 14C yr BP reconstruction are comparatively small. Patterns of change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America also show a change in biome assignment to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucat??n peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded. At 18 000±1000 14C yr BP 61 samples from 34 sites record vegetation that reflects a generally cool and dry environment. Cool grass/shrubland prevalent in southeast Brazil, Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site retains cool temperate

  6. Insights into the mechanisms of vertical transmission of HIV-1. BIOMED2 Working Group on the in utero transmission of HIV-1.

    Science.gov (United States)

    Menu, E; Mognetti, B; Moussa, M; Nardese, V; Tresoldi, L; Tscherning, C; Mbopi Keou, F X; Dubanchet, S; Mauclere, P; Fenyö, E M; Scarlatti, G; Barre-Sinoussi, F; Chaouat, G

    1997-12-01

    This paper is a summary of three oral presentations, as well as the ensuing discussion, at the Rijeka/Opatija 3rd Alps Adria Immunology meeting by three members of the European Biomed group on vertical transmission of HIV (G. Chaouat, F. Barre-Sinoussi, G. Scarlatti). This group also involves the laboratories of D. Dormont (CEA, Fontenay aux roses, France), P. Gounon (Electron Microscopy, the Pasteur Institute, France; Irène Athanassakis, University of Crete, Greece; Eva Maria Fenyö, Karolinska Institute, Sweden; and Larry Guilbert, Canada). As such, this paper intends to be neither a review, nor an original article, but rather is an opinion paper discussing the working hypothesis of this network, as well as some of their recent results, which were presented at this meeting. The paper was issued at the request of the organizers of the meeting.

  7. Balancing forest-regeneration probabilities and maintenance costs in dry grasslands of high conservation priority

    Science.gov (United States)

    Bolliger, Janine; Edwards, Thomas C.; Eggenberg, Stefan; Ismail, Sascha; Seidl, Irmi; Kienast, Felix

    2011-01-01

    Abandonment of agricultural land has resulted in forest regeneration in species-rich dry grasslands across European mountain regions and threatens conservation efforts in this vegetation type. To support national conservation strategies, we used a site-selection algorithm (MARXAN) to find optimum sets of floristic regions (reporting units) that contain grasslands of high conservation priority. We sought optimum sets that would accommodate 136 important dry-grassland species and that would minimize forest regeneration and costs of management needed to forestall predicted forest regeneration. We did not consider other conservation elements of dry grasslands, such as animal species richness, cultural heritage, and changes due to climate change. Optimal sets that included 95–100% of the dry grassland species encompassed an average of 56–59 floristic regions (standard deviation, SD 5). This is about 15% of approximately 400 floristic regions that contain dry-grassland sites and translates to 4800–5300 ha of dry grassland out of a total of approximately 23,000 ha for the entire study area. Projected costs to manage the grasslands in these optimum sets ranged from CHF (Swiss francs) 5.2 to 6.0 million/year. This is only 15–20% of the current total estimated cost of approximately CHF30–45 million/year required if all dry grasslands were to be protected. The grasslands of the optimal sets may be viewed as core sites in a national conservation strategy.

  8. Grassland futures in Great Britain - Productivity assessment and scenarios for land use change opportunities.

    Science.gov (United States)

    Qi, Aiming; Holland, Robert A; Taylor, Gail; Richter, Goetz M

    2018-09-01

    To optimise trade-offs provided by future changes in grassland use intensity, spatially and temporally explicit estimates of respective grassland productivities are required at the systems level. Here, we benchmark the potential national availability of grassland biomass, identify optimal strategies for its management, and investigate the relative importance of intensification over reversion (prioritising productivity versus environmental ecosystem services). Process-conservative meta-models for different grasslands were used to calculate the baseline dry matter yields (DMY; 1961-1990) at 1km 2 resolution for the whole UK. The effects of climate change, rising atmospheric [CO 2 ] and technological progress on baseline DMYs were used to estimate future grassland productivities (up to 2050) for low and medium CO 2 emission scenarios of UKCP09. UK benchmark productivities of 12.5, 8.7 and 2.8t/ha on temporary, permanent and rough-grazing grassland, respectively, accounted for productivity gains by 2010. By 2050, productivities under medium emission scenario are predicted to increase to 15.5 and 9.8t/ha on temporary and permanent grassland, respectively, but not on rough grassland. Based on surveyed grassland distributions for Great Britain in 2010 the annual availability of grassland biomass is likely to rise from 64 to 72milliontonnes by 2050. Assuming optimal N application could close existing productivity gaps of ca. 40% a range of management options could deliver additional 21∗10 6 tonnes of biomass available for bioenergy. Scenarios of changes in grassland use intensity demonstrated considerable scope for maintaining or further increasing grassland production and sparing some grassland for the provision of environmental ecosystem services. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Species-rich semi-natural grasslands have a higher resistance but a lower resilience than intensively managed agricultural grasslands in response to climate anomalies

    NARCIS (Netherlands)

    Keersmaecker, De Wanda; Rooijen, van Nils; Lhermitte, Stef; Tits, Laurent; Schaminée, Joop; Coppin, Pol; Honnay, Olivier; Somers, Ben

    2016-01-01

    The stable delivery of ecosystem services provided by grasslands is strongly dependent on the stability of grassland ecosystem functions such as biomass production. Biomass production is in turn strongly affected by the frequency and intensity of climate extremes. The aim of this study is to

  10. Spatio-temporal characteristics of evapotranspiration and water use efficiency in grasslands of Xinjiang%新疆草地蒸散与水分利用效率的时空特征

    Institute of Scientific and Technical Information of China (English)

    黄小涛; 罗格平

    2017-01-01

    Aims Xinjiang is located in the hinterland of the Eurasian arid areas,with grasslands widely distributed.Grasslands in Xinjiang provide significant economic and ecological benefits.However,research on evapotranspiration (ET) and water use efficiency (WUE) of the grasslands is still relatively weak.This study aimed to explore the spatio-temporal characteristics on ET and WUE in the grasslands of Xinjiang in the context of climate change.Methods The Biome-BGC model was used to determine the spatio-temporal characteristics of ET and WUE of the grasslands over the period 1979-2012 across different seasons,areas and grassland types in Xinjiang.Important findings The average annual ET in the grasslands of Xinjiang was estimated at 245.7 mm,with interannual variations generally consistent with that of precipitation.Overall,the value of ET was lower than that of precipitation.The higher values of ET mainly distributed in the Tianshan Mountains,Altai Mountains,Altun Mountains and the low mountain areas on the northern slope of Kunlun Mountains.The lower values of ET mainly distributed in the highland areas of Kunlun Mountains and the desert plains.Over the period 1979-2012,average annual ET was 183.2 mm in the grasslands of southern Xinjiang,357.9 mm in the grasslands of the Tianshan Mountains,and 221.3 mm in grasslands of northern Xinjiang.In winter,ET in grasslands of northern Xinjiang was slightly higher than that of Tianshan Mountains.Average annual ET ranked among grassland types as:mid-mountain meadow > swamp meadow > typical grassland > desert grassland > alpine meadow > saline meadow.The highest ET value occurred in summer,and the lowest ET value occurred in winter,with ET in spring being slightly higher than that in autumn.The higher WUE values mainly distributed in the areas of Tianshan Mountains and Altai Mountains.The lower WUE values mainly distributed in the highland areas of Kunlun Mountains and part of the desert plains.The average annual WUE in

  11. Herbivores and nutrients control grassland plant diversity via light limitation

    Science.gov (United States)

    Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Cheng-Jin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen Ingman; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Leakey, Andrew D.B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

    2014-01-01

    Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

  12. Direct effects of cattle on grassland birds in Canada.

    Science.gov (United States)

    Bleho, Barbara I; Koper, Nicola; Machtans, Craig S

    2014-06-01

    Effects of grazing on grassland birds are generally thought to be indirect, through alteration of vegetation structure; however, livestock can also affect nest survival directly through trampling and other disturbances (e.g., livestock-induced abandonment). We extracted data on nest fates from 18 grazing studies conducted in Canada. We used these data to assess rates of nest destruction by cattle among 9 ecoregions and between seasonal and rotational grazing systems. Overall, few nests were destroyed by cattle (average 1.5% of 9132 nests). Nest destruction was positively correlated with grazing pressure (i.e., stocking rate or grazing intensity), but nest survival was higher in more heavily grazed areas for some species. Because rates of destruction of grassland bird nests by cattle are low in Canada, management efforts to reduce such destruction may not be of ecological or economic value in Canada. © 2014 Society for Conservation Biology.

  13. The biological transport of radionuclides in grassland and freshwater ecosystems

    International Nuclear Information System (INIS)

    Rudge, S.A.

    1989-12-01

    This thesis examines the biological transport of radionuclides through terrestrial and aquatic ecosystems, with particular reference to radiocaesium. The semi-natural grassland habitat was located at Drigg, W. Cumbria, contaminated primarily by radioactive fallout, from several sources over the past decade. Advantage was made of the deposition of radionuclides from the Chernobyl reactor incident, which occurred during the early stages of the investigation. The study examined the distribution of radiocaesium for the major components of the grassland ecosystem, within the soil-plant-invertebrate-small mammal food chain. Data concerning temporal fluctuation of radionuclide transfer factors between food chain components are presented. The final section examines the spatial distribution of radiocaesium in sediment and the freshwater eel (Anguilla anguilla) in a small stream contaminated by radioactive effluent. The relationship between activity levels in eels and the sediments in which they rest and forage was investigated. Factors influencing uptake of radiocaesium in freshwater fish were also examined. (author)

  14. Acidification of sandy grasslands - consequences for plant diversity

    DEFF Research Database (Denmark)

    Olsson, Pål Axel; Mårtensson, Linda-Maria; Bruun, Hans Henrik

    2009-01-01

    soil; a number of nationally red-listed species showed a similar pattern. Plant species diversity and number of red-listed species increased with slope. Where the topsoil had been acidified, limestone was rarely present above a depth of 30 cm. The presence of limestone restricts the availability......Questions: (1) Does soil acidification in calcareous sandy grasslands lead to loss of plant diversity? (2) What is the relationship between the soil content of lime and the plant availability of mineral nitrogen (N) and phosphorus (P) in sandy grasslands? Location: Sandy glaciofluvial deposits......). Environmental variables were recorded at each plot, and soil samples were analysed for exchangeable P and N, as well as limestone content and pH. Data were analysed with regression analysis and canonical correspondence analysis. Results: Plant species richness was highest on weakly acid to slightly alkaline...

  15. Species interactions reverse grassland responses to changing climate.

    Science.gov (United States)

    Suttle, K B; Thomsen, Meredith A; Power, Mary E

    2007-02-02

    Predictions of ecological response to climate change are based largely on direct climatic effects on species. We show that, in a California grassland, species interactions strongly influence responses to changing climate, overturning direct climatic effects within 5 years. We manipulated the seasonality and intensity of rainfall over large, replicate plots in accordance with projections of leading climate models and examined responses across several trophic levels. Changes in seasonal water availability had pronounced effects on individual species, but as precipitation regimes were sustained across years, feedbacks and species interactions overrode autecological responses to water and reversed community trajectories. Conditions that sharply increased production and diversity through 2 years caused simplification of the food web and deep reductions in consumer abundance after 5 years. Changes in these natural grassland communities suggest a prominent role for species interactions in ecosystem response to climate change.

  16. Composition, phenology and restoration of campo rupestre mountain grasslands - Brazil

    OpenAIRE

    Le Stradic, Soizig

    2012-01-01

    Global environmental changes, especially land-use changes, have profound effects on both ecosystem functioning and biodiversity, having already altered many ecosystem services. These losses emphasize the need to preserve what remains; however when conservation programs are not sufficient, restoring areas that have been destroyed or disturbed can improve conservation efforts and mitigate damages. This work focuses on campos rupestres, Neotropical grasslands found at altitudes, which are part o...

  17. Carbon dynamics in an Imperata grassland in Northeast India

    Directory of Open Access Journals (Sweden)

    Amrabati Thokchom

    2016-01-01

    Full Text Available Carbon stocks and soil CO2 flux were assessed in an Imperata cylindrica grassland of Manipur, Northeast India. Carbon stocks in the vegetative components were estimated to be 11.17 t C/ha and soil organic carbon stocks were 55.94 t C/ha to a depth of 30 cm. The rates of carbon accumulation in above-ground and below-ground biomass were estimated to be 11.85 t C/ha/yr and 11.71 t C/ha/yr, respectively. Annual soil CO2 flux was evaluated as 6.95 t C/ha and was highly influenced by soil moisture, soil temperature and soil organic carbon as well as by C stocks in above-ground biomass. Our study on the carbon budget of the grassland ecosystem revealed that annually 23.56 t C/ha was captured by the vegetation through photosynthesis, and 6.95 t C/ha was returned to the atmosphere through roots and microbial respiration, with a net balance of 16.61 t C/ha/yr being retained in the grassland ecosystem. Thus the present Imperata grassland exhibited a high capacity to remove atmospheric CO2 and to induce high C stocks in the soil provided it is protected from burning and overgrazing.Keywords: Above-ground biomass, below-ground biomass, carbon stocks, carbon storage, net primary productivity, soil CO2 flux.DOI: 10.17138/TGFT(419-28  

  18. Making Grasslands Sustainable in Mongolia: Herders' Livelihoods and Climate Change

    OpenAIRE

    Asian Development Bank (ADB)

    2014-01-01

    The threats posed by climate change have significant impacts on Mongolia’s grassland ecosystems and herders’ livelihoods. This publication discusses the auses of climate change and its impacts on livelihoods and ecosystems for herders and the general public. It explains how good pasture management and livestock roductivity are important for increasing incomes and provides information on adaptation practices. It also identifies sustainable management practices that can increase communities’ re...

  19. Effects of wind turbines on upland nesting birds in Conservation Reserve Program grasslands

    Science.gov (United States)

    Leddy, K.L.; Higgins, K.F.; Naugle, D.E.

    1999-01-01

    Grassland passerines were surveyed during summer 1995 on the Buffalo Ridge Wind Resource Area in southwestern Minnesota to determine the relative influence of wind turbines on overall densities of upland nesting birds in Conservation Reserve Program (CRP) grasslands. Birds were surveyed along 40 m fixed width transects that were placed along wind turbine strings within three CRP fields and in three CRP fields without turbines. Conservation Reserve Program grasslands without turbines and areas located 180 m from turbines supported higher densities (261.0-312.5 males/100 ha) of grassland birds than areas within 80 m of turbines (58.2-128.0 males/100 ha). Human disturbance, turbine noise, and physical movements of turbines during operation may have disturbed nesting birds. We recommend that wind turbines be placed within cropland habitats that support lower densities of grassland passerines than those found in CRP grasslands.

  20. Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances

    Science.gov (United States)

    Fort, Florian; Jouany, Claire; Cruz, Pablo

    2015-01-01

    Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance. PMID:25741353

  1. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    Full Text Available Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2.s(-1 and clipping (2.06 μmol.m(-2.s(-1 than under grazing (1.65 μmol.m-(2.s(-1 over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP. Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content and biotic (ANPP and BNPP factors regulate soil respiration in the semiarid temperate grassland of northern China.

  2. Soil Respiration in Semiarid Temperate Grasslands under Various Land Management.

    Science.gov (United States)

    Wang, Zhen; Ji, Lei; Hou, Xiangyang; Schellenberg, Michael P

    2016-01-01

    Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17 μmol.m(-2).s(-1)) and clipping (2.06 μmol.m(-2).s(-1)) than under grazing (1.65 μmol.m-(2).s(-1)) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China.

  3. Hierarchical traits distances explain grassland Fabaceae species’ ecological niches distances

    Directory of Open Access Journals (Sweden)

    Florian eFort

    2015-02-01

    Full Text Available Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e. ecological niches. We measured a wide range of functional traits (root traits, leaf traits and whole plant traits in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species’ ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance.

  4. Morphofunctional diversity of equine of varied genetic compositions raised in the Pantanal biome of Brazil.

    Science.gov (United States)

    de Rezende, Marcos Paulo Gonçalves; de Souza, Julio Cesar; Carneiro, Paulo Luiz Souza; Bozzi, Riccardo; Jardim, Rodrigo Jose Delgado; Malhado, Carlos Henrique Mendes

    2018-06-01

    Evaluating phenotypic diversity makes it possible to identify discrepancies in aptitudes among animals of different genetic bases, which is an indicator of adaptive or selective differences between populations. The objective of this work was to evaluate the morphofunctional diversity of 452 male and female adult equines (Arabian, Quarter Mile, Pantaneiro, and Criollo breeds, and undefined crossbreeds of horses and mules) raised in the Pantanal biome (Brazil). Linear measurements were performed to estimate conformation indexes. Initially, a discriminant analysis was performed, regardless of the animal's size, followed by factor analysis. The factors were characterized and used as new variables. The diversity among equines and their relationship with the factors were evaluated using multivariate analysis. The factors were classified according to their decreasing importance: balance, rusticity, and robustness for the measurement factors; and load, ability, conformation, and equilibrium for the index factors. The genetic groups of equines have well-defined morphofunctional characteristics. The main differences are based on the rusticity and ability typologies in relation to those based on performance. Equines introduced to the Pantanal biome presented a more robust and compact body with good conformation. As a result, these horses may have superior athletic performance during equestrian activities when compared to the Pantaneiro local breed. However, this biotype may represent less rusticity (less adaptive capacity). Therefore, the regional breed can be equal or better in equestrian activities than breeds introduced to the Pantanal biome. Thus, breeders may cross horses from local breeds as an alternative to those introduced. Undefined crossbred male equines presented a different profile from the Pantaneiro breed, which may indicate little use of crossbreeds in breeding.

  5. Identification of priority conservation areas and potential corridors for jaguars in the Caatinga biome, Brazil.

    Science.gov (United States)

    Morato, Ronaldo Gonçalves; Ferraz, Katia Maria Paschoaletto Micchi de Barros; de Paula, Rogério Cunha; de Campos, Cláudia Bueno

    2014-01-01

    The jaguar, Panthera onca, is a top predator with the extant population found within the Brazilian Caatinga biome now known to be on the brink of extinction. Designing new conservation units and potential corridors are therefore crucial for the long-term survival of the species within the Caatinga biome. Thus, our aims were: 1) to recognize suitable areas for jaguar occurrence, 2) to delineate areas for jaguar conservation (PJCUs), 3) to design corridors among priority areas, and 4) to prioritize PJCUs. A total of 62 points records of jaguar occurrence and 10 potential predictors were analyzed in a GIS environment. A predictive distributional map was obtained using Species Distribution Modeling (SDM) as performed by the Maximum Entropy (Maxent) algorithm. Areas equal to or higher than the median suitability value of 0.595 were selected as of high suitability for jaguar occurrence and named as Priority Jaguar Conservation Units (PJCU). Ten PJCUs with sizes varying from 23.6 km2 to 4,311.0 km2 were identified. Afterwards, we combined the response curve, as generated by SDM, and expert opinions to create a permeability matrix and to identify least cost corridors and buffer zones between each PJCU pair. Connectivity corridors and buffer zone for jaguar movement included an area of 8.884,26 km2 and the total corridor length is about 160.94 km. Prioritizing criteria indicated the PJCU representing c.a. 68.61% of the total PJCU area (PJCU # 1) as of high priority for conservation and connectivity with others PJCUs (PJCUs # 4, 5 and 7) desirable for the long term survival of the species. In conclusion, by using the jaguar as a focal species and combining SDM and expert opinion we were able to create a valid framework for practical conservation actions at the Caatinga biome. The same approach could be used for the conservation of other carnivores.

  6. Identification of priority conservation areas and potential corridors for jaguars in the Caatinga biome, Brazil.

    Directory of Open Access Journals (Sweden)

    Ronaldo Gonçalves Morato

    Full Text Available The jaguar, Panthera onca, is a top predator with the extant population found within the Brazilian Caatinga biome now known to be on the brink of extinction. Designing new conservation units and potential corridors are therefore crucial for the long-term survival of the species within the Caatinga biome. Thus, our aims were: 1 to recognize suitable areas for jaguar occurrence, 2 to delineate areas for jaguar conservation (PJCUs, 3 to design corridors among priority areas, and 4 to prioritize PJCUs. A total of 62 points records of jaguar occurrence and 10 potential predictors were analyzed in a GIS environment. A predictive distributional map was obtained using Species Distribution Modeling (SDM as performed by the Maximum Entropy (Maxent algorithm. Areas equal to or higher than the median suitability value of 0.595 were selected as of high suitability for jaguar occurrence and named as Priority Jaguar Conservation Units (PJCU. Ten PJCUs with sizes varying from 23.6 km2 to 4,311.0 km2 were identified. Afterwards, we combined the response curve, as generated by SDM, and expert opinions to create a permeability matrix and to identify least cost corridors and buffer zones between each PJCU pair. Connectivity corridors and buffer zone for jaguar movement included an area of 8.884,26 km2 and the total corridor length is about 160.94 km. Prioritizing criteria indicated the PJCU representing c.a. 68.61% of the total PJCU area (PJCU # 1 as of high priority for conservation and connectivity with others PJCUs (PJCUs # 4, 5 and 7 desirable for the long term survival of the species. In conclusion, by using the jaguar as a focal species and combining SDM and expert opinion we were able to create a valid framework for practical conservation actions at the Caatinga biome. The same approach could be used for the conservation of other carnivores.

  7. Reactivity continuum modeling of leaf, root, and wood decomposition across biomes

    Science.gov (United States)

    Koehler, Birgit; Tranvik, Lars J.

    2015-07-01

    Large carbon dioxide amounts are released to the atmosphere during organic matter decomposition. Yet the large-scale and long-term regulation of this critical process in global carbon cycling by litter chemistry and climate remains poorly understood. We used reactivity continuum (RC) modeling to analyze the decadal data set of the "Long-term Intersite Decomposition Experiment," in which fine litter and wood decomposition was studied in eight biome types (224 time series). In 32 and 46% of all sites the litter content of the acid-unhydrolyzable residue (AUR, formerly referred to as lignin) and the AUR/nitrogen ratio, respectively, retarded initial decomposition rates. This initial rate-retarding effect generally disappeared within the first year of decomposition, and rate-stimulating effects of nutrients and a rate-retarding effect of the carbon/nitrogen ratio became more prevalent. For needles and leaves/grasses, the influence of climate on decomposition decreased over time. For fine roots, the climatic influence was initially smaller but increased toward later-stage decomposition. The climate decomposition index was the strongest climatic predictor of decomposition. The similar variability in initial decomposition rates across litter categories as across biome types suggested that future changes in decomposition may be dominated by warming-induced changes in plant community composition. In general, the RC model parameters successfully predicted independent decomposition data for the different litter-biome combinations (196 time series). We argue that parameterization of large-scale decomposition models with RC model parameters, as opposed to the currently common discrete multiexponential models, could significantly improve their mechanistic foundation and predictive accuracy across climate zones and litter categories.

  8. Clonality analysis of lymphoid proliferations using the BIOMED-2 clonality assays: a single institution experience

    Science.gov (United States)

    Kokovic, Ira; Novakovic, Barbara Jezersek; Cerkovnik, Petra; Novakovic, Srdjan

    2014-01-01

    Background Clonality determination in patients with lymphoproliferative disorders can improve the final diagnosis. The aim of our study was to evaluate the applicative value of standardized BIOMED-2 gene clonality assay protocols for the analysis of clonality of lymphocytes in a group of different lymphoid proliferations. Materials and methods. With this purpose, 121 specimens from 91 patients with suspected lymphoproliferations submitted for routine diagnostics from January to December 2011 were retrospectively analyzed. According to the final diagnosis, our series comprised 32 cases of B-cell lymphomas, 38 cases of non-Hodgkin’s T-cell lymphomas and 51 cases of reactive lymphoid proliferations. Clonality testing was performed using the BIOMED-2 clonality assays. Results The determined sensitivity of the TCR assay was 91.9%, while the sensitivity of the IGH assay was 74.2%. The determined specificity of the IGH assay was 73.3% in the group of lymphomas and 87.2% in the group of reactive lesions. The determined specificity of the TCR assay was 62.5% in the group of lymphomas and 54.3% in the group of reactive lesions. Conclusions In the present study, we confirmed the utility of standardized BIOMED-2 clonality assays for the detection of clonality in a routine diagnostical setting of non-Hodgkin’s lymphomas. Reactions for the detection of the complete IGH rearrangements and reactions for the detection of the TCR rearrangements are a good choice for clonality testing of a wide range of lymphoid proliferations and specimen types while the reactions for the detection of incomplete IGH rearrangements have not shown any additional diagnostic value. PMID:24991205

  9. Global soil-climate-biome diagram: linking soil properties to climate and biota

    Science.gov (United States)

    Zhao, X.; Yang, Y.; Fang, J.

    2017-12-01

    As a critical component of the Earth system, soils interact strongly with both climate and biota and provide fundamental ecosystem services that maintain food, climate, and human security. Despite significant progress in digital soil mapping techniques and the rapidly growing quantity of observed soil information, quantitative linkages between soil properties, climate and biota at the global scale remain unclear. By compiling a large global soil database, we mapped seven major soil properties (bulk density [BD]; sand, silt and clay fractions; soil pH; soil organic carbon [SOC] density [SOCD]; and soil total nitrogen [STN] density [STND]) based on machine learning algorithms (regional random forest [RF] model) and quantitatively assessed the linkage between soil properties, climate and biota at the global scale. Our results demonstrated a global soil-climate-biome diagram, which improves our understanding of the strong correspondence between soils, climate and biomes. Soil pH decreased with greater mean annual precipitation (MAP) and lower mean annual temperature (MAT), and the critical MAP for the transition from alkaline to acidic soil pH decreased with decreasing MAT. Specifically, the critical MAP ranged from 400-500 mm when the MAT exceeded 10 °C but could decrease to 50-100 mm when the MAT was approximately 0 °C. SOCD and STND were tightly linked; both increased in accordance with lower MAT and higher MAP across terrestrial biomes. Global stocks of SOC and STN were estimated to be 788 ± 39.4 Pg (1015 g, or billion tons) and 63 ± 3.3 Pg in the upper 30-cm soil layer, respectively, but these values increased to 1654 ± 94.5 Pg and 133 ± 7.8 Pg in the upper 100-cm soil layer, respectively. These results reveal quantitative linkages between soil properties, climate and biota at the global scale, suggesting co-evolution of the soil, climate and biota under conditions of global environmental change.

  10. Sensitivity Analysis of Biome-Bgc Model for Dry Tropical Forests of Vindhyan Highlands, India

    Science.gov (United States)

    Kumar, M.; Raghubanshi, A. S.

    2011-08-01

    A process-based model BIOME-BGC was run for sensitivity analysis to see the effect of ecophysiological parameters on net primary production (NPP) of dry tropical forest of India. The sensitivity test reveals that the forest NPP was highly sensitive to the following ecophysiological parameters: Canopy light extinction coefficient (k), Canopy average specific leaf area (SLA), New stem C : New leaf C (SC:LC), Maximum stomatal conductance (gs,max), C:N of fine roots (C:Nfr), All-sided to projected leaf area ratio and Canopy water interception coefficient (Wint). Therefore, these parameters need more precision and attention during estimation and observation in the field studies.

  11. SENSITIVITY ANALYSIS OF BIOME-BGC MODEL FOR DRY TROPICAL FORESTS OF VINDHYAN HIGHLANDS, INDIA

    OpenAIRE

    M. Kumar; A. S. Raghubanshi

    2012-01-01

    A process-based model BIOME-BGC was run for sensitivity analysis to see the effect of ecophysiological parameters on net primary production (NPP) of dry tropical forest of India. The sensitivity test reveals that the forest NPP was highly sensitive to the following ecophysiological parameters: Canopy light extinction coefficient (k), Canopy average specific leaf area (SLA), New stem C : New leaf C (SC:LC), Maximum stomatal conductance (gs,max), C:N of fine roots (C:Nfr), All-sided to...

  12. Characterizing forest carbon stocks at tropical biome and landscape level in Mount Apo National Park, Philippines

    Science.gov (United States)

    Rubas, L. C.

    2012-12-01

    Forest resources sequester and store carbon, and serve as a natural brake on climate change. In the tropics, the largest source of greenhouse emission is from deforestation and forest degradation (Gibbs et al 2007). This paper attempts to compile sixty (60) existing studies on using remote sensing to measure key environmental forest indicators at two levels of scales: biome and landscape level. At the tropical forest biome level, there is not as much remote sensing studies that have been done as compared to other forest biomes. Also, existing studies on tropical Asia is still sparse compared to other tropical regions in Latin America and Africa. Biomass map is also produced for the tropical biome using keyhole macro language (KML) which is projected on Google Earth. The compiled studies showed there are four indicators being measured using remote sensors in tropical forest. These are biomass, landcover classification, deforestation and cloud cover. The landscape level will focus on Mount Apo National Park in the Philippines which is encompassing a total area of 54,974.87 hectares. It is one of the ten priority sites targeted in the World Bank-assisted Biodiversity Conservation Program. This park serves as the major watershed for the three provinces with 19 major rivers emanating from the montane formations. Only a small fraction of the natural forest that once covered the country remains. In spite of different policies that aim to reduce logging recent commercial deforestation, illegal logging and agricultural expansion pose an important threat to the remaining forest areas. In some locations in the country, these hotspots of deforestation overlap with the protected areas (Verburg et al 2006). The study site was clipped using ArcGIS from the forest biomass carbon density map produced by Gibbs and Brown (2007). Characterization on this national park using vegetation density, elevation, slope, land cover and precipitation will be conducted to determine factors that

  13. Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota.

    Science.gov (United States)

    Byrne, M; Yeates, D K; Joseph, L; Kearney, M; Bowler, J; Williams, M A J; Cooper, S; Donnellan, S C; Keogh, J S; Leys, R; Melville, J; Murphy, D J; Porch, N; Wyrwoll, K-H

    2008-10-01

    The integration of phylogenetics, phylogeography and palaeoenvironmental studies is providing major insights into the historical forces that have shaped the Earth's biomes. Yet our present view is biased towards arctic and temperate/tropical forest regions, with very little focus on the extensive arid regions of the planet. The Australian arid zone is one of the largest desert landform systems in the world, with a unique, diverse and relatively well-studied biota. With foci on palaeoenvironmental and molecular data, we here review what is known about the assembly and maintenance of this biome in the context of its physical history, and in comparison with other mesic biomes. Aridification of Australia began in the Mid-Miocene, around 15 million years, but fully arid landforms in central Australia appeared much later, around 1-4 million years. Dated molecular phylogenies of diverse taxa show the deepest divergences of arid-adapted taxa from the Mid-Miocene, consistent with the onset of desiccation. There is evidence of arid-adapted taxa evolving from mesic-adapted ancestors, and also of speciation within the arid zone. There is no evidence for an increase in speciation rate during the Pleistocene, and most arid-zone species lineages date to the Pliocene or earlier. The last 0.8 million years have seen major fluctuations of the arid zone, with large areas covered by mobile sand dunes during glacial maxima. Some large, vagile taxa show patterns of recent expansion and migration throughout the arid zone, in parallel with the ice sheet-imposed range shifts in Northern Hemisphere taxa. Yet other taxa show high lineage diversity and strong phylogeographical structure, indicating persistence in multiple localised refugia over several glacial maxima. Similar to the Northern Hemisphere, Pleistocene range shifts have produced suture zones, creating the opportunity for diversification and speciation through hybridisation, polyploidy and parthenogenesis. This review highlights

  14. NEE and GPP dynamic evolution at two biomes in the upper Spanish plateau

    Science.gov (United States)

    Sánchez, María Luisa; Pardo, Nuria; Pérez, Isidro Alberto; García, Maria de los Angeles

    2014-05-01

    In order to assess the ability of dominant biomes to act as a CO2 sink, two eddy correlation stations close to each other in central Spain have been concurrently operational since March 2008 until the present. The land use of the first station, AC, is a rapeseed rotating crop consisting of annual rotation of non-irrigated rapeseed, barley, peas, rye, and sunflower, respectively. The land use of the second, CIBA, is a mixture of open shrubs/crops, with open shrubs being markedly dominant. The period of measurements covered variable general meteorological conditions. 2009 and 2012 were dominated by drought, whereas 2010 was the rainiest year. Annual rainfall during 2008 and 2009 was close to the historical averaged annual means. This paper presents the dynamic evolution of NEE-8d and GPP-8d observed at the AC station over five years and compares the results with those concurrently observed at the CIBA station. GGP 8-d estimates at both stations were determined using a Light Use Efficiency Model, LUE. Input data for the LUE model were the FPAR 8-d products supplied by MODIS, PAR in situ measurements, and a scalar f, varying between 0 and 1, to take account of the reduction in maximum PAR conversion efficiency, ɛ0, under limiting environmental conditions. f values were assumed to be dependent on air temperature and evaporative fraction, EF, which was considered a proxy of soil moisture. ɛ0, a key parameter, which depends on land use types, was derived through the results of a linear regression fit between the GPP 8-d eddy covariance composites observed and the LUE concurrent 8-d model estimates. Over the five-year study period, both biomes behaved as CO2 sinks. However, the ratio of the NEE-8d total accumulated at AC and CIBA, respectively, was close to a factor two, revealing the effectiveness of the studied crops as CO2 sinks. On an annual basis, accumulated NEE-8d exhibited major variability in both biomes. At CIBA, the results were largely dominated by the

  15. Extensiones biométricas para bases de datos objeto- relacionales

    OpenAIRE

    Miranda, Ernesto; Ruíz, Silvia; Aguirre, Juan José; Herlein, Mauro; Etchart, Graciela; Alvez, Carlos E.

    2017-01-01

    La autenticación de personas basadas en rasgos biométricos se ha vuelto muy popular en los últimos años como consecuencia de la baja en los costos de los sensores requeridos, su inclusión en dispositivos de consumo masivo y el surgimiento de vulnerabilidades debido al uso de múltiples claves de acceso a diferentes sitios que requieren cierto nivel de seguridad como ser cuentas de correo, sitios de banca electrónica, sistemas corporativos, etc. De todos los rasgos utilizados en biometría, el i...

  16. Evaluation of semiarid grassland degradation in North China from multiple perspectives

    Science.gov (United States)

    Han, D.; Wang, G.; Xue, B. L.; Xu, X.

    2017-12-01

    There has been increasing interest in grassland ecosystem degradation resulting from intensive human activity and climate change, especially in arid and semiarid regions. Species composition, grassland desertification, and aboveground biomass (AGB) are used as indicators of grassland degradation in this study. We comprehensively analyzed variations in these three indicators in semiarid grassland in North China, on multiple time scales, based on MODIS products and field sampling datasets. Since 1984, species composition has become simpler and species indicative of grassland degradation, such as Potentilla acaulis and Artemisia frigida, have become dominant. These changes indicate that serious grassland degradation has occurred since 1984. Grassland degradation was also analyzed on shorter time scales. Analyses of interannual variations during 2005-2015 showed that desertification decreased and average AGB in the growth season increased over the study area, indicating that grassland was recovering. Analyses of spatial variations showed that the position of slightly desertified grassland shifted and formed a band in the west, where the lowest AGB in the growth season was recorded but tendency ratio of AGB increased from 2005 to 2015. Climatic factors had critical effects on grassland degradation, as identified by the three indicators on different time scales. The simpler species composition resulted from the increase in average temperature and decrease in average precipitation over the past 30 years. For nearly a decade, an increase in precipitation and decreases in temperature and potential evapotranspiration reduced desertification and increased AGB in the growth season overall. Consequently, there has distinct difference in grassland degradation between analysis results on above two time scales, indicating multiple perspectives should be considered to accurately assess the state and characteristics of grassland degradation.

  17. Exacerbated grassland degradation and desertification in Central Asia during 2000-2014.

    Science.gov (United States)

    Zhang, Geli; Biradar, Chandrashekhar M; Xiao, Xiangming; Dong, Jinwei; Zhou, Yuting; Qin, Yuanwei; Zhang, Yao; Liu, Fang; Ding, Mingjun; Thomas, Richard J

    2018-03-01

    Grassland degradation and desertification is a complex process, including both state conversion (e.g., grasslands to deserts) and gradual within-state change (e.g., greenness dynamics). Existing studies hardly separated the two components and analyzed it as a whole based on time series vegetation index data, which cannot provide a clear and comprehensive picture for grassland degradation and desertification. Here we propose an integrated assessment strategy, by considering both state conversion and within-state change of grasslands, to investigate grassland degradation and desertification process in Central Asia. First, annual maps of grasslands and sparsely vegetated land were generated to track the state conversions between them. The results showed increasing grasslands were converted to sparsely vegetated lands from 2000 to 2014, with the desertification region concentrating in the latitude range of 43-48° N. A frequency analysis of grassland vs. sparsely vegetated land classification in the last 15 yr allowed a recognition of persistent desert zone (PDZ), persistent grassland zone (PGZ), and transitional zone (TZ). The TZ was identified in southern Kazakhstan as one hotspot that was unstable and vulnerable to desertification. Furthermore, the trend analysis of Enhanced Vegetation Index during thermal growing season (EVI TGS ) was investigated in individual zones using linear regression and Mann-Kendall approaches. An overall degradation across the area was found; moreover, the second desertification hotspot was identified in northern Kazakhstan with significant decreasing in EVI TGS , which was located in PGZ. Finally, attribution analyses of grassland degradation and desertification were conducted by considering precipitation, temperature, and three different drought indices. We found persistent droughts were the main factor for grassland degradation and desertification in Central Asia. Considering both state conversion and gradual within-state change

  18. Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass

    Directory of Open Access Journals (Sweden)

    Fengge Zhang

    2018-04-01

    Full Text Available In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly (p = 0.019 increased following amendment with 9,000 kg ha−1 of Trichoderma biofertilizer (composted cattle manure + inoculum compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha−1 biofertilizer. This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha−1 increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella. Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella. According to our structural equation modeling (SEM, Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma

  19. Impacts of tree rows on grassland birds and potential nest predators: a removal experiment.

    Science.gov (United States)

    Ellison, Kevin S; Ribic, Christine A; Sample, David W; Fawcett, Megan J; Dadisman, John D

    2013-01-01

    Globally, grasslands and the wildlife that inhabit them are widely imperiled. Encroachment by shrubs and trees has widely impacted grasslands in the past 150 years. In North America, most grassland birds avoid nesting near woody vegetation. Because woody vegetation fragments grasslands and potential nest predator diversity and abundance is often greater along wooded edge and grassland transitions, we measured the impacts of removing rows of trees and shrubs that intersected grasslands on potential nest predators and the three most abundant grassland bird species (Henslow's sparrow [Ammodramus henslowii], Eastern meadowlark [Sturnella magna], and bobolink [Dolichonyx oryzivorus]) at sites in Wisconsin, U.S.A. We monitored 3 control and 3 treatment sites, for 1 yr prior to and 3 yr after tree row removal at the treatment sites. Grassland bird densities increased (2-4 times for bobolink and Henslow's sparrow) and nesting densities increased (all 3 species) in the removal areas compared to control areas. After removals, Henslow's sparrows nested within ≤50 m of the treatment area, where they did not occur when tree rows were present. Most dramatically, activity by woodland-associated predators nearly ceased (nine-fold decrease for raccoon [Procyon lotor]) at the removals and grassland predators increased (up to 27 times activity for thirteen-lined ground squirrel [Ictidomys tridecemlineatus]). Nest success did not increase, likely reflecting the increase in grassland predators. However, more nests were attempted by all 3 species (175 versus 116) and the number of successful nests for bobolinks and Henslow's sparrows increased. Because of gains in habitat, increased use by birds, greater production of young, and the effective removal of woodland-associated predators, tree row removal, where appropriate based on the predator community, can be a beneficial management action for conserving grassland birds and improving fragmented and degraded grassland ecosystems.

  20. Impacts of tree rows on grassland birds and potential nest predators: a removal experiment.

    Directory of Open Access Journals (Sweden)

    Kevin S Ellison

    Full Text Available Globally, grasslands and the wildlife that inhabit them are widely imperiled. Encroachment by shrubs and trees has widely impacted grasslands in the past 150 years. In North America, most grassland birds avoid nesting near woody vegetation. Because woody vegetation fragments grasslands and potential nest predator diversity and abundance is often greater along wooded edge and grassland transitions, we measured the impacts of removing rows of trees and shrubs that intersected grasslands on potential nest predators and the three most abundant grassland bird species (Henslow's sparrow [Ammodramus henslowii], Eastern meadowlark [Sturnella magna], and bobolink [Dolichonyx oryzivorus] at sites in Wisconsin, U.S.A. We monitored 3 control and 3 treatment sites, for 1 yr prior to and 3 yr after tree row removal at the treatment sites. Grassland bird densities increased (2-4 times for bobolink and Henslow's sparrow and nesting densities increased (all 3 species in the removal areas compared to control areas. After removals, Henslow's sparrows nested within ≤50 m of the treatment area, where they did not occur when tree rows were present. Most dramatically, activity by woodland-associated predators nearly ceased (nine-fold decrease for raccoon [Procyon lotor] at the removals and grassland predators increased (up to 27 times activity for thirteen-lined ground squirrel [Ictidomys tridecemlineatus]. Nest success did not increase, likely reflecting the increase in grassland predators. However, more nests were attempted by all 3 species (175 versus 116 and the number of successful nests for bobolinks and Henslow's sparrows increased. Because of gains in habitat, increased use by birds, greater production of young, and the effective removal of woodland-associated predators, tree row removal, where appropriate based on the predator community, can be a beneficial management action for conserving grassland birds and improving fragmented and degraded grassland

  1. The influence of boundary features on grassland-edge communities of Alta Murgia

    OpenAIRE

    Cassano, Stefania; Alignier, Audrey; Forte, Luigi; Labadessa, Rocco; Mairota, Paola

    2016-01-01

    Many studies suggest the importance of boundary features on plant community dynamics. Our aim was to investigate the influence of boundary features on edge plant assemblages in semi-natural dry grasslands. For this purpose we selected 16 grassland edges in the central portion of the Natura 2000 site Murgia Alta, in southeastern Italy. These sites were selected according to a combination of boundary features, i.e. the adjoining land use type (road or cereal crop), slope (grassland tilted towar...

  2. Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass.

    Science.gov (United States)

    Zhang, Fengge; Huo, Yunqian; Cobb, Adam B; Luo, Gongwen; Zhou, Jiqiong; Yang, Gaowen; Wilson, Gail W T; Zhang, Yingjun

    2018-01-01

    In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly ( p = 0.019) increased following amendment with 9,000 kg ha -1 of Trichoderma biofertilizer (composted cattle manure + inoculum) compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha -1 biofertilizer). This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS) revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha -1 ) increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella . Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella . According to our structural equation modeling (SEM), Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma

  3. Impacts of land-use and land-cover change on stream hydrochemistry in the Cerrado and Amazon biomes.

    Science.gov (United States)

    Nóbrega, Rodolfo L B; Guzha, Alphonce C; Lamparter, Gabriele; Amorim, Ricardo S S; Couto, Eduardo G; Hughes, Harold J; Jungkunst, Hermann F; Gerold, Gerhard

    2018-04-14

    Studies on the impacts of land-use and land-cover change on stream hydrochemistry in active deforestation zones of the Amazon agricultural frontier are limited and have often used low-temporal-resolution datasets. Moreover, these impacts are not concurrently assessed in well-established agricultural areas and new deforestations hotspots. We aimed to identify these impacts using an experimental setup to collect high-temporal-resolution hydrological and hydrochemical data in two pairs of low-order streams in catchments under contrasting land use and land cover (native vegetation vs. pasture) in the Amazon and Cerrado biomes. Our results indicate that the conversion of natural landscapes to pastures increases carbon and nutrient fluxes via streamflow in both biomes. These changes were the greatest in total inorganic carbon in the Amazon and in potassium in the Cerrado, representing a 5.0- and 5.5-fold increase in the fluxes of each biome, respectively. We found that stormflow, which is often neglected in studies on stream hydrochemistry in the tropics, plays a substantial role in the carbon and nutrient fluxes, especially in the Amazon biome, as its contributions to hydrochemical fluxes are mostly greater than the volumetric contribution to the total streamflow. These findings demonstrate that assessments of the impacts of deforestation in the Amazon and Cerrado biomes should also take into account rapid hydrological pathways; however, this can only be achieved through collection of high-temporal-resolution data. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Large-scale impact of climate change vs. land-use change on future biome shifts in Latin America.

    Science.gov (United States)

    Boit, Alice; Sakschewski, Boris; Boysen, Lena; Cano-Crespo, Ana; Clement, Jan; Garcia-Alaniz, Nashieli; Kok, Kasper; Kolb, Melanie; Langerwisch, Fanny; Rammig, Anja; Sachse, René; van Eupen, Michiel; von Bloh, Werner; Clara Zemp, Delphine; Thonicke, Kirsten

    2016-11-01

    Climate change and land-use change are two major drivers of biome shifts causing habitat and biodiversity loss. What is missing is a continental-scale future projection of the estimated relative impacts of both drivers on biome shifts over the course of this century. Here, we provide such a projection for the biodiverse region of Latin America under four socio-economic development scenarios. We find that across all scenarios 5-6% of the total area will undergo biome shifts that can be attributed to climate change until 2099. The relative impact of climate change on biome shifts may overtake land-use change even under an optimistic climate scenario, if land-use expansion is halted by the mid-century. We suggest that constraining land-use change and preserving the remaining natural vegetation early during this century creates opportunities to mitigate climate-change impacts during the second half of this century. Our results may guide the evaluation of socio-economic scenarios in terms of their potential for biome conservation under global change. © 2016 John Wiley & Sons Ltd.

  5. Biome depletion in conjunction with evolutionary mismatches could play a role in the etiology of neurofibromatosis 1.

    Science.gov (United States)

    Beales, Donna L

    2015-04-01

    Neurofibromatosis 1 (NF1) arises de novo in a striking 30-50% of cases, pointing toward an environmental etiology, though none has been clearly identified. The Biome Depletion Theory posits that the absence of mutualistic and commensal organisms within the human body coupled with modern lifestyle alterations may have profoundly deleterious effects, inclusive of immunologic derangement that is thought to result in allergy, atopy, and numerous autoimmune diseases. Biome depletion has been implicated as a factor in the etiology of both multiple sclerosis and autism spectrum disorders; biome reconstitution, i.e. replenishment of the biome with certain keynote species, is being used in the treatment of these and other autoimmune states. Neurofibromatosis 1 has been associated with allergy, various autoimmune states, multiple sclerosis, and autism. Recent research has posited that NF1, multiple sclerosis and autism may all arise from disturbances in the neural crest during gestation. This paper hypothesizes that there is indirect evidence that a highly inflammatory uterine state may precipitate epigenetic changes in vulnerable NF-related genes in the course of fetal development. The etiology of NF1 may lie in the absence of immunomodulation by commensal and mutualistic species once ubiquitously present in the environment, as well as through adoption of a modern lifestyle that contributes to chronic inflammation. Replenishment of helminths and other missing organisms to the human biome prior to conception as well as addressing nutritional status, psychological stress, and environmental exposures may prevent the development of NF1. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. [Vegetation index estimation by chlorophyll content of grassland based on spectral analysis].

    Science.gov (United States)

    Xiao, Han; Chen, Xiu-Wan; Yang, Zhen-Yu; Li, Huai-Yu; Zhu, Han

    2014-11-01

    Comparing the methods of existing remote sensing research on the estimation of chlorophyll content, the present paper confirms that the vegetation index is one of the most practical and popular research methods. In recent years, the increasingly serious problem of grassland degradation. This paper, firstly, analyzes the measured reflectance spectral curve and its first derivative curve in the grasslands of Songpan, Sichuan and Gongger, Inner Mongolia, conducts correlation analysis between these two spectral curves and chlorophyll content, and finds out the regulation between REP (red edge position) and grassland chlorophyll content, that is, the higher the chlorophyll content is, the higher the REIP (red-edge inflection point) value would be. Then, this paper constructs GCI (grassland chlorophyll index) and selects the most suitable band for retrieval. Finally, this paper calculates the GCI by the use of satellite hyperspectral image, conducts the verification and accuracy analysis of the calculation results compared with chlorophyll content data collected from field of twice experiments. The result shows that for grassland chlorophyll content, GCI has stronger sensitivity than other indices of chlorophyll, and has higher estimation accuracy. GCI is the first proposed to estimate the grassland chlorophyll content, and has wide application potential for the remote sensing retrieval of grassland chlorophyll content. In addition, the grassland chlorophyll content estimation method based on remote sensing retrieval in this paper provides new research ideas for other vegetation biochemical parameters' estimation, vegetation growth status' evaluation and grassland ecological environment change's monitoring.

  7. Grassland birds wintering at U.S. Navy facilities in southern Texas

    Science.gov (United States)

    Woodin, Marc C.; Skoruppa, Mary Kay; Bryan, Pearce D.; Ruddy, Amanda J.; Hickman, Graham C.

    2010-01-01

    Grassland birds have undergone widespread decline throughout North America during the past several decades. Causes of this decline include habitat loss and fragmentation because of conversion of grasslands to cropland, afforestation in the East, brush and shrub invasion in the Southwest and western United States, and planting of exotic grass species to enhance forage production. A large number of exotic plant species, including grasses, have been introduced in North America, but most research on the effects of these invasions on birds has been limited to breeding birds, primarily those in northern latitudes. Research on the effects of exotic grasses on birds in winter has been extremely limited.This is the first study in southern Texas to examine and compare winter bird responses to native and exotic grasslands. This study was conducted during a period of six years (2003–2009) on United States Navy facilities in southern Texas including Naval Air Station–Corpus Christi, Naval Air Station–Kingsville, Naval Auxiliary Landing Field Waldron, Naval Auxiliary Landing Field Orange Grove, and Escondido Ranch, all of which contained examples of native grasslands, exotic grasslands, or both. Data from native and exotic grasslands were collected and compared for bird abundance and diversity; ground cover, vegetation density, and floristic diversity; bird and vegetation relationships; diversity of insects and arachnids; and seed abundance and diversity. Effects of management treatments in exotic grasslands were evaluated by comparing numbers and diversity of birds and small mammals in mowed, burned, and control areas.To determine bird abundance and bird species richness, birds were surveyed monthly (December–February) during the winters of 2003–2008 in transects (100 meter × 20 meter) located in native and exotic grasslands distributed at all five U.S. Navy facilities. To compare vegetation in native and exotic grasslands, vegetation characteristics were measured

  8. Anaerobic oxidation of methane in grassland soils used for cattle husbandry

    Directory of Open Access Journals (Sweden)

    A. Bannert

    2012-10-01

    Full Text Available While the importance of anaerobic methane oxidation has been reported for marine ecosystems, the role of this process in soils is still questionable. Grasslands used as pastures for cattle overwintering show an increase in anaerobic soil micro-sites caused by animal treading and excrement deposition. Therefore, anaerobic potential methane oxidation activity of severely impacted soil from a cattle winter pasture was investigated in an incubation experiment under anaerobic conditions using 13C-labelled methane. We were able to detect a high microbial activity utilizing CH4 as nutrient source shown by the respiration of 13CO2. Measurements of possible terminal electron acceptors for anaerobic oxidation of methane were carried out. Soil sulfate concentrations were too low to explain the oxidation of the amount of methane added, but enough nitrate and iron(III were detected. However, only nitrate was consumed during the experiment. 13C-PLFA analyses clearly showed the utilization of CH4 as nutrient source mainly by organisms harbouring 16:1ω7 PLFAs. These lipids were also found as most 13C-enriched fatty acids by Raghoebarsing et al. (2006 after addition of 13CH4 to an enrichment culture coupling denitrification of nitrate to anaerobic oxidation of methane. This might be an indication for anaerobic oxidation of methane by relatives of "Candidatus Methylomirabilis oxyfera" in the investigated grassland soil under the conditions of the incubation experiment.

  9. Aspectos biométricos do desenvolvimento testicular e corporal em cutias (Dasyprocta aguti criadas em cativeiros

    Directory of Open Access Journals (Sweden)

    Antônio Chaves de Assis-Neto

    2003-01-01

    Full Text Available Analisou-se os dados biométricos do desenvolvimento testicular e peso corporal de 31 cutias (Dasyprocta aguti desde o nascimento até os 14 meses de idade. As correlações entre o peso corporal, idade e parâmetros testiculares apresentaram-se altamente significativas. O peso testicular, o volume testicular, assim como os demais parâmetros biométricos testiculares (comprimento, diâmetro e perímetro, evoluíram lenta e gradualmente até os 8 meses de idade. A partir dos 9 meses, o crescimento foi mais rápido. O desenvolvimento biométrico do testículo pode ser dividido em duas fases, de 0 - 8 meses e de 9 - 14 meses de idade, sendo 9 meses considerado ponto de corte em se tratando de desenvolvimento testicular de cutias criadas em cativeiro.

  10. Detection of wild animals as carriers of Leptospira by PCR in the Pantanal biome, Brazil.

    Science.gov (United States)

    Vieira, Anahi S; Narduche, Lorena; Martins, Gabriel; Schabib Péres, Igor A H F; Zimmermann, Namor P; Juliano, Raquel S; Pellegrin, Aiesca O; Lilenbaum, Walter

    2016-11-01

    Leptospiral infection is widespread in wildlife. In this context, wild ecosystems in tropical countries hold a vast biodiversity, including several species that may act as potential reservoirs of leptospires. The Pantanal biome presents highly favorable environmental conditions for the occurrence of leptospirosis, such as high temperatures, constant flooding, and high biodiversity. The purpose of this study was to detect wild animals as carriers of Leptospira sp. using direct methods (PCR and culture) in the Pantanal biome, Brazil. A total of 35 animals were studied, namely Cerdocyon thous, Nasua nasua, Ozotoceros bezoarticus, and Sus scrofa species. Blood for serology (MAT) and urine for bacteriological culturing and PCR was sampled. The most prevalent serogroups were Javanica and Djasiman. Additionally, 40.6% of these animals presented PCR positive reactions. Seroreactivity associated with the high frequency of leptospiral carriers among the different studied species suggests a high level of exposure of the studied animals to pathogenic Leptospira strains. Our results are still limited and the actual role of the studied animals in the epidemiology of leptospirosis in the Pantanal region remains to be elucidated. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Above- and Belowground Biomass Allocation in Shrub Biomes across the Northeast Tibetan Plateau

    Science.gov (United States)

    Yang, Yuanhe; Yang, Lucun; Zhou, Guoying

    2016-01-01

    Biomass partitioning has been explored across various biomes. However, the strategies of allocation in plants still remain contentious. This study investigated allocation patterns of above- and belowground biomass at the community level, using biomass survey from the Tibetan Plateau. We explored above- and belowground biomass by conducting three consecutive sampling campaigns across shrub biomes on the northeast Tibetan Plateau during 2011–2013. We then documented the above-ground biomass (AGB), below-ground biomass (BGB) and root: shoot ratio (R/S) and the relationships between R/S and environment factors using data from 201 plots surveyed from 67 sites. We further examined relationships between above-ground and below-ground biomass across various shrub types. Our results indicated that the median values of AGB, BGB, and R/S in Tibetan shrub were 1102.55, 874.91 g m-2, and 0.85, respectively. R/S showed significant trend with mean annual precipitation (MAP), while decreased with mean annual temperature (MAT). Reduced major axis analysis indicated that the slope of the log-log relationship between above- and belowground biomass revealed a significant difference from 1.0 over space, supporting the optimal hypothesis. Interestingly, the slopes of the allometric relationship between log AGB and log BGB differed significantly between alpine and desert shrub. Our findings supported the optimal theory of above- and belowground biomass partitioning in Tibetan shrub, while the isometric hypothesis for alpine shrub at the community level. PMID:27119379

  12. Contribution to the discussions on the origin of the cerrado biome: Brazilian savanna

    Directory of Open Access Journals (Sweden)

    MHO. Pinheiro

    Full Text Available Theories that attempt to explain the origin of the cerrado biome are mostly based on the isolated action of three major factors: climate, fire and soil. Another factor that has been mentioned is that of human interference. We hypothesise that the evolutionary origin of this biome resulted from the complex interaction of climate, fire and soil, with climate being the triggering agent of this assumed interaction. Fire, as well as acid and dystrophic soils, would be factors involved in the selection of savanna species throughout climatic events, during the Tertiary and the Quaternary, e.g. Pliocene and Pleistocene. The genesis of the physiognomies that would give rise to cerrado sensu lato, rather than forest formations, could have occurred due to the strong pressure exerted by the reduction in water availability, and the selection of the species adapted to the new conditions imposed by the environment. The characteristics of cerrado sensu lato soil, originated from edaphic impoverishment caused by lixiviation and successive past fires, would remain, even after hydric availability increased following the Pleistocene glaciations.

  13. Feedbacks between land cover and climate changes in the Brazilian Amazon and Cerrado biomes

    Science.gov (United States)

    Coe, M. T.; Silverio, D. V.; Bustamante, M.; Macedo, M.; Shimbo, J.; Brando, P. M.

    2016-12-01

    An estimated 20% of Amazon forests and 45% of Cerrado savannas have been cleared to make way for the expansion of croplands and pasturelands in Brazil. Although deforestation rates have decreased or remained steady over the last decade, the cumulative area deforested continues to grow in both biomes. These land-use transitions are expected to influence regional climate by reducing evapotranspiration (ET), increasing land surface temperatures (LST), and ultimately reducing regional precipitation. Here we present results from spatial analyses to quantify the impact of land-use transitions on the regional climate of the Amazon-Cerrado agricultural frontier. The analyses combine satellite observations and model outputs from the MODIS dataset. Results from the southeastern Amazon indicate that transitions from forest to pasture or cropland decreased mean annual ET (by 24% and 32%, respectively) and increased LST (by 4.2°C and 6.4°C). Preliminary results from the Cerrado indicate that transitions from woody savannas to pasture or cropland also result in substantial reductions in mean annual ET (23% and 20%, respectively) and increases in LST (by 1.6°C in both cases). These results reinforce the need to better understand how land-use change at regional scales may alter climate by changing ecosystem properties (beyond carbon stocks and fluxes). It is important to evaluate these responses across different biomes, particularly in tropical regions under increasing deforestation pressure.

  14. Cities as Novel Biomes;Recognizing Urban Ecosystem Services as Anthropogenic

    Directory of Open Access Journals (Sweden)

    Stephanie ePincetl

    2015-12-01

    Full Text Available Urban Ecosystem Science is now an established science, arising along side the historic shift of humans to becoming in majority urban dwellers. In this Perspective I suggest there is a need to develop a new framework for UES as embedded in distinct urban biomes that can be classified by city-type and typologized. UES are largely the artifact of human decision making from what to plant where, to determining the urban infrastructure type in which UES will be placed. Developing urban typologies by climate zone, level of development, size and history will better enable the understanding of UES. I attempt to show the rise of the importance of nature, and of urban nature following the development of industrial city, and the importance of human intent in creating these urban ecosystems over time. If humans choose to manage cities through increasing UES, this will require coupled shifts, the shift in rules and regulations, goals and processes and shifts in urban form, infrastructure and function – socio-technical-ecological changes – driven by human decision-making. Such efforts will vary widely by city -- by urban biome.

  15. Aquatic ecosystem responses to Holocene climate change and biome development in boreal, central Asia

    Science.gov (United States)

    Mackay, Anson W.; Bezrukova, Elena V.; Leng, Melanie J.; Meaney, Miriam; Nunes, Ana; Piotrowska, Natalia; Self, Angela; Shchetnikov, Alexander; Shilland, Ewan; Tarasov, Pavel; Wang, Luo; White, Dustin

    2012-05-01

    Boreal ecosystems are highly vulnerable to climate change, and severe ecological impacts in the near future are virtually certain to occur. We undertook a multiproxy study on an alpine lake (ESM-1) at the modern tree-line in boreal, southern Siberia. Steppe and tundra biomes were extensive in eastern Sayan landscapes during the early Holocene. Boreal forest quickly expanded by 9.1 ka BP, and dominated the landscape until c 0.7 ka BP, when the greatest period of compositional turnover occurred. At this time, alpine meadow landscape expanded and Picea obovata colonised new habitats along river valleys and lake shorelines, because of prevailing cool, moist conditions. During the early Holocene, chironomid assemblages were dominated by cold stenotherms. Diatoms for much of the Holocene were dominated by alkaliphilous, fragilarioid taxa, up until 0.2 ka BP, when epiphytic species expanded, indicative of increased habitat availability. C/N mass ratios ranged between 9.5 and 13.5 (11.1-15.8 C/N atomic ratios), indicative of algal communities dominating organic matter contributions to bottom sediments with small, persistent contributions from vascular plants. However, δ13C values increased steadily from -34.9‰ during the early Holocene (9.3 ka BP) to -24.8‰ by 0.6 ka BP. This large shift in magnitude may be due to a number of factors, including increasing within-lake productivity, increasing disequilibrium between the isotopic balance of the lake with the atmosphere as the lake became isotopically ‘mature’, and declining soil respiration linked to small, but distinct retreat in forest biomes. The influence of climatic variables on landscape vegetation was assessed using redundancy analysis (RDA), a linear, direct ordination technique. Changes in July insolation at 60 °N significantly explained over one-fifth of the variation in species composition, while changes in estimates of northern hemisphere temperature and ice-rafted debris events in the North Atlantic

  16. Estimating N2O processes during grassland renewal and grassland conversion to maize cropping using N2O isotopocules

    Science.gov (United States)

    Buchen, Caroline; Well, Reinhard; Flessa, Heinz; Fuß, Roland; Helfrich, Mirjam; Lewicka-Szczebak, Dominika

    2017-04-01

    Grassland break-up due to grassland renewal and grassland conversion to cropland can lead to a flush of mineral nitrogen from decomposition of the old grass sward and the decomposition of soil organic matter. Moreover, increased carbon and nitrogen mineralisation can result in enhanced nitrous oxide (N2O) emissions. As N2O is known to be an important greenhouse gas and a major precursor for ozone depletion, its emissions need to be mitigated by adjusting agricultural management practices. Therefore, it is necessary to understand the N2O processes involved, as well as the contribution of N2O reduction to N2. Apart from the widely used 15N gas flux method, natural abundance isotopic analysis of the four most abundant isotopocules of N2O species is a promising alternative to assess N2O production pathways. We used stable isotope analyses of soil-emitted N2O (δ18ON2O, δ15NN2Obulk and δ15NN2OSP= intramolecular distribution of 15N within the linear N2O molecule) with an isotopocule mapping approach to simultaneously estimate the magnitude of N2O reduction to N2 and the fraction of N2O originating from the bacterial denitrification pathway or fungal denitrification and/or nitrification. This approach is based on endmember areas of isotopic values for the N2O produced from different sources reported in the literature. For this purpose, we calculated two main scenarios with different assumptions for N2O produced: N2O is reduced to N2 before residual N2O is mixed with N2O of various sources (Scenario a) and vice versa (Scenario b). Based on this, we applied seven different scenario variations, where we evaluated the range of possible values for the potential N2O production pathways (heterotrophic bacterial denitrification and/or nitrifier denitrification and fungal denitrification and/or nitrification). This was done by using a range of isotopic endmember values and assuming different fractionation factors of N2O reduction in order to find the most reliable scenario

  17. Flower resource and land management drives hoverfly communities and bee abundance in seminatural and agricultural grasslands.

    Science.gov (United States)

    Lucas, Andrew; Bull, James C; de Vere, Natasha; Neyland, Penelope J; Forman, Dan W

    2017-10-01

    Pollination is a key ecosystem service, and appropriate management, particularly in agricultural systems, is essential to maintain a diversity of pollinator guilds. However, management recommendations frequently focus on maintaining plant communities, with the assumption that associated invertebrate populations will be sustained. We tested whether plant community, flower resources, and soil moisture would influence hoverfly (Syrphidae) abundance and species richness in floristically-rich seminatural and floristically impoverished agricultural grassland communities in Wales (U.K.) and compared these to two Hymenoptera genera, Bombus, and Lasioglossum . Interactions between environmental variables were tested using generalized linear modeling, and hoverfly community composition examined using canonical correspondence analysis. There was no difference in hoverfly abundance, species richness, or bee abundance, between grassland types. There was a positive association between hoverfly abundance, species richness, and flower abundance in unimproved grasslands. However, this was not evident in agriculturally improved grassland, possibly reflecting intrinsically low flower resource in these habitats, or the presence of plant species with low or relatively inaccessible nectar resources. There was no association between soil moisture content and hoverfly abundance or species richness. Hoverfly community composition was influenced by agricultural improvement and the amount of flower resource. Hoverfly species with semiaquatic larvae were associated with both seminatural and agricultural wet grasslands, possibly because of localized larval habitat. Despite the absence of differences in hoverfly abundance and species richness, distinct hoverfly communities are associated with marshy grasslands, agriculturally improved marshy grasslands, and unimproved dry grasslands, but not with improved dry grasslands. Grassland plant community cannot be used as a proxy for pollinator

  18. Structural development and web service based sensitivity analysis of the Biome-BGC MuSo model

    Science.gov (United States)

    Hidy, Dóra; Balogh, János; Churkina, Galina; Haszpra, László; Horváth, Ferenc; Ittzés, Péter; Ittzés, Dóra; Ma, Shaoxiu; Nagy, Zoltán; Pintér, Krisztina; Barcza, Zoltán

    2014-05-01

    Studying the greenhouse gas exchange, mainly the carbon dioxide sink and source character of ecosystems is still a highly relevant research topic in biogeochemistry. During the past few years research focused on managed ecosystems, because human intervention has an important role in the formation of the land surface through agricultural management, land use change, and other practices. In spite of considerable developments current biogeochemical models still have uncertainties to adequately quantify greenhouse gas exchange processes of managed ecosystem. Therefore, it is an important task to develop and test process-based biogeochemical models. Biome-BGC is a widely used, popular biogeochemical model that simulates the storage and flux of water, carbon, and nitrogen between the ecosystem and the atmosphere, and within the components of the terrestrial ecosystems. Biome-BGC was originally developed by the Numerical Terradynamic Simulation Group (NTSG) of University of Montana (http://www.ntsg.umt.edu/project/biome-bgc), and several other researchers used and modified it in the past. Our research group developed Biome-BGC version 4.1.1 to improve essentially the ability of the model to simulate carbon and water cycle in real managed ecosystems. The modifications included structural improvements of the model (e.g., implementation of multilayer soil module and drought related plant senescence; improved model phenology). Beside these improvements management modules and annually varying options were introduced and implemented (simulate mowing, grazing, planting, harvest, ploughing, application of fertilizers, forest thinning). Dynamic (annually varying) whole plant mortality was also enabled in the model to support more realistic simulation of forest stand development and natural disturbances. In the most recent model version separate pools have been defined for fruit. The model version which contains every former and new development is referred as Biome-BGC MuSo (Biome

  19. Análisis comparativo de distintas toolkits para el reconocimiento biométrico de personas mediante voz

    OpenAIRE

    Ruíz, Silvia; Miranda, Ernesto; Herlein, Mauro; Etchart, Graciela; Alvez, Carlos E.

    2017-01-01

    El objetivo de este trabajo es realizar un análisis comparativo de distintas toolkits para el reconocimiento biométrico de personas mediante voz. Hoy en día los sistemas de identificación de personas se han convertido en una necesidad para la sociedad. A medida que avanza la tecnología y la aplicación de la misma en entornos tanto de ocio como de seguridad, la evolución en desarrollo biométrico es muy grande. Los sistemas de identificación o verificación tradicionales (tarjetas o claves) se h...

  20. Improved clonality detection in B-cell lymphoma using a semi-nested modification of the BIOMED-2 PCR assay for IGH rearrangement: A paraffin-embedded tissue study.

    Science.gov (United States)

    Sakamoto, Yuma; Masaki, Ayako; Aoyama, Satsuki; Han, Shusen; Saida, Kosuke; Fujii, Kana; Takino, Hisashi; Murase, Takayuki; Iida, Shinsuke; Inagaki, Hiroshi

    2017-09-01

    The BIOMED-2 PCR protocol for targeting the IGH gene is widely employed for detecting clonality in B-cell malignancies. Unfortunately, the detection of clonality with this method is not very sensitive when paraffin sections are used as a DNA source. To increase the sensitivity, we devised a semi-nested modification of a JH consensus primer. The clonality detection rates of three assays were compared: the standard BIOMED-2, BIOMED-2 assay followed by BIOMED-2 re-amplification, and BIOMED-2 assay followed by semi-nested BIOMED-2. We tested more than 100 cases using paraffin-embedded tissues of various B-cell lymphomas, and found that the clonality detection rates with the above three assays were 63.9%, 79.6%, and 88.0%, respectively. While BIOMED-2 re-amplification was significantly more sensitive than the standard BIOMED-2, the semi-nested BIOMED-2 was significantly more sensitive than both the standard BIOMED-2 and BIOMED-2 re-amplification. An increase in sensitivity was observed in all lymphoma subtypes examined. In conclusion, tumor clonality may be detected in nearly 90% of B-cell lymphoma cases with semi-nested BIOMED-2. This ancillary assay may be useful when the standard BIOMED-2 fails to detect clonality in histopathologically suspected B-cell lymphomas. © 2017 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

  1. Machine Learning to Assess Grassland Productivity in Southeastern Arizona

    Science.gov (United States)

    Ponce-Campos, G. E.; Heilman, P.; Armendariz, G.; Moser, E.; Archer, V.; Vaughan, R.

    2015-12-01

    We present preliminary results of machine learning (ML) techniques modeling the combined effects of climate, management, and inherent potential on productivity of grazed semi-arid grasslands in southeastern Arizona. Our goal is to support public land managers determine if agency management policies are meeting objectives and where to focus attention. Monitoring in the field is becoming more and more limited in space and time. Remotely sensed data cover the entire allotments and go back in time, but do not consider the key issue of species composition. By estimating expected vegetative production as a function of site potential and climatic inputs, management skill can be assessed through time, across individual allotments, and between allotments. Here we present the use of Random Forest (RF) as the main ML technique, in this case for the purpose of regression. Our response variable is the maximum annual NDVI, a surrogate for grassland productivity, as generated by the Google Earth Engine cloud computing platform based on Landsat 5, 7, and 8 datasets. PRISM 33-year normal precipitation (1980-2013) was resampled to the Landsat scale. In addition, the GRIDMET climate dataset was the source for the calculation of the annual SPEI (Standardized Precipitation Evapotranspiration Index), a drought index. We also included information about landscape position, aspect, streams, ponds, roads and fire disturbances as part of the modeling process. Our results show that in terms of variable importance, the 33-year normal precipitation, along with SPEI, are the most important features affecting grasslands productivity within the study area. The RF approach was compared to a linear regression model with the same variables. The linear model resulted in an r2 = 0.41, whereas RF showed a significant improvement with an r2 = 0.79. We continue refining the model by comparison with aerial photography and to include grazing intensity and infrastructure from units/allotments to assess the

  2. Land-use intensification causes multitrophic homogenization of grassland communities.

    Science.gov (United States)

    Gossner, Martin M; Lewinsohn, Thomas M; Kahl, Tiemo; Grassein, Fabrice; Boch, Steffen; Prati, Daniel; Birkhofer, Klaus; Renner, Swen C; Sikorski, Johannes; Wubet, Tesfaye; Arndt, Hartmut; Baumgartner, Vanessa; Blaser, Stefan; Blüthgen, Nico; Börschig, Carmen; Buscot, Francois; Diekötter, Tim; Jorge, Leonardo Ré; Jung, Kirsten; Keyel, Alexander C; Klein, Alexandra-Maria; Klemmer, Sandra; Krauss, Jochen; Lange, Markus; Müller, Jörg; Overmann, Jörg; Pašalić, Esther; Penone, Caterina; Perović, David J; Purschke, Oliver; Schall, Peter; Socher, Stephanie A; Sonnemann, Ilja; Tschapka, Marco; Tscharntke, Teja; Türke, Manfred; Venter, Paul Christiaan; Weiner, Christiane N; Werner, Michael; Wolters, Volkmar; Wurst, Susanne; Westphal, Catrin; Fischer, Markus; Weisser, Wolfgang W; Allan, Eric

    2016-12-08

    Land-use intensification is a major driver of biodiversity loss. Alongside reductions in local species diversity, biotic homogenization at larger spatial scales is of great concern for conservation. Biotic homogenization means a decrease in β-diversity (the compositional dissimilarity between sites). Most studies have investigated losses in local (α)-diversity and neglected biodiversity loss at larger spatial scales. Studies addressing β-diversity have focused on single or a few organism groups (for example, ref. 4), and it is thus unknown whether land-use intensification homogenizes communities at different trophic levels, above- and belowground. Here we show that even moderate increases in local land-use intensity (LUI) cause biotic homogenization across microbial, plant and animal groups, both above- and belowground, and that this is largely independent of changes in α-diversity. We analysed a unique grassland biodiversity dataset, with abundances of more than 4,000 species belonging to 12 trophic groups. LUI, and, in particular, high mowing intensity, had consistent effects on β-diversity across groups, causing a homogenization of soil microbial, fungal pathogen, plant and arthropod communities. These effects were nonlinear and the strongest declines in β-diversity occurred in the transition from extensively managed to intermediate intensity grassland. LUI tended to reduce local α-diversity in aboveground groups, whereas the α-diversity increased in belowground groups. Correlations between the β-diversity of different groups, particularly between plants and their consumers, became weaker at high LUI. This suggests a loss of specialist species and is further evidence for biotic homogenization. The consistently negative effects of LUI on landscape-scale biodiversity underscore the high value of extensively managed grasslands for conserving multitrophic biodiversity and ecosystem service provision. Indeed, biotic homogenization rather than local diversity

  3. Grassland carbon sequestration and emissions following cultivation in a mixed crop rotation

    DEFF Research Database (Denmark)

    Acharya, Bharat Sharma; Rasmussen, Jim; Eriksen, Jørgen

    2012-01-01

    Grasslands are potential carbon sinks to reduce unprecedented increase in atmospheric CO2. Effect of age (1–4-year-old) and management (slurry, grazing multispecies mixture) of a grass phase mixed crop rotation on carbon sequestration and emissions upon cultivation was compared with 17-year...... biomass was highest in 4-year-old grassland, but all 1–4-year-old grasslands were in between the pea field (0.81 ± 0.094 g kg−1 soil) and the 17-year-old grassland (3.17 ± 0.22 g kg−1 soil). Grazed grasslands had significantly higher root biomass than cut grasslands. There was no significant difference...... in the CO2 emissions within 1–4-year-old grasslands. Only the 17-year-old grassland showed markedly higher CO2 emissions (4.9 ± 1.1 g CO2 kg−1 soil). Differences in aboveground and root biomass did not affect CO2 emissions, and slurry application did not either. The substantial increase in root biomass...

  4. Response of predominant soil bacteria to grassland succession as monitored by ribosomal RNA analyses

    NARCIS (Netherlands)

    Felske, A.

    1999-01-01

    The research described in this thesis was aimed to provide insight into the effects of grassland succession on the composition of the soil bacteria community in the Drentse A agricultural research area. The Drentse A meadows represent grassland succession at different stages. Since 30 years

  5. Modelling the carbon cycle of grassland in the Netherlands under various management strategies and environmental conditions.

    NARCIS (Netherlands)

    Pol-van Dasselaar, van den A.; Lantinga, E.A.

    1995-01-01

    A simulation model of the grassland carbon cycle (CCGRASS) was developed to evaluate the long-term effects of different management strategies and various environmental conditions on carbon sequestration in a loam soil under permanent grassland in the Netherlands. The model predicted that the rate of

  6. Temporal dynamics of soil nematode communities in a grassland plant diversity experiment.

    NARCIS (Netherlands)

    Viketoft, M.; Sohlenius, B.; Bostrom, S.; Palmborg, C.; Bengtsson, J.; Berg, M.P.; Kuss-Danell, K.

    2011-01-01

    We report here on an 8-year study examining links between plant and nematode communities in a grassland plant diversity experiment, located in the north of Sweden on previous agricultural soil. The examined plots contained 1, 4 and 12 common grassland plant species from three functional groups;

  7. The Impact of Ecological Construction Programs on Grassland Conservation in Inner Mongolia, China

    NARCIS (Netherlands)

    Liu, Min; Dries, Liesbeth; Heijman, Wim; Huang, Jikun; Zhu, Xueqin; Hu, Yuanning; Chen, Haibin

    2018-01-01

    A series of Ecological Construction Programs have been initiated to protect the condition of grasslands in China during recent decades. However, grassland degradation is still severe, and conditions have not been restored as intended. This paper aims to empirically examine the effectiveness of these

  8. 78 FR 19444 - Pawnee National Grassland, Colorado; Oil and Gas Leasing Analysis Environmental Impact Statement

    Science.gov (United States)

    2013-04-01

    ... Leasing Analysis on the Pawnee National Grassland (PNG), was signed. That decision determined which Lands... National Grassland. Much of the PNG's federal mineral estate made available per the 1997 ROD has already... [36 CFR 228.102(e)]. Accordingly, the PNG finds it is necessary to disclose the potential effects of...

  9. Long-term after-effects of fertilisation on restoration of calcareous grasslands

    NARCIS (Netherlands)

    Smits, N.A.C.; Bobbink, R.; Willems, J.H.

    2008-01-01

    Question: What are the long-term implications of former fertilisation for the ecological restoration of calcareous grasslands? Location: Gerendal, Limburg, The Netherlands. Methods: In 1970, ten permanent plots were established in just abandoned agricultural calcareous grassland under a regime of

  10. 77 FR 75119 - Dakota Prairie Grasslands, North Dakota; Oil and Gas Development Supplemental Environmental...

    Science.gov (United States)

    2012-12-19

    ... DEPARTMENT OF AGRICULTURE Forest Service Dakota Prairie Grasslands, North Dakota; Oil and Gas... to prepare a supplemental environmental impact statement. SUMMARY: In June of 2003, the Dakota... Dakota Prairie Grasslands Land and Resource Management Plan, based on the 2001 Northern Great Plains...

  11. Differentiating climate- and human-induced drivers of grassland degradation in the Liao River Basin, China.

    Science.gov (United States)

    He, Chunyang; Tian, Jie; Gao, Bin; Zhao, Yuanyuan

    2015-01-01

    Quantitatively distinguishing grassland degradation due to climatic variations from that due to human activities is of great significance to effectively governing degraded grassland and realizing sustainable utilization. The objective of this study was to differentiate these two types of drivers in the Liao River Basin during 1999-2009 using the residual trend (RESTREND) method and to evaluate the applicability of the method in semiarid and semihumid regions. The relationship between the normalized difference vegetation index (NDVI) and each climatic factor was first determined. Then, the primary driver of grassland degradation was identified by calculating the change trend of the normalized residuals between the observed and the predicted NDVI assuming that climate change was the only driver. We found that the RESTREND method can be used to quantitatively and effectively differentiate climate and human drivers of grassland degradation. We also found that the grassland degradation in the Liao River Basin was driven by both natural processes and human activities. The driving factors of grassland degradation varied greatly across the study area, which included regions having different precipitation and altitude. The degradation in the Horqin Sandy Land, with lower altitude, was driven mainly by human activities, whereas that in the Kungl Prairie, with higher altitude and lower precipitation, was caused primarily by climate change. Therefore, the drivers of degradation and local conditions should be considered in an appropriate strategy for grassland management to promote the sustainability of grasslands in the Liao River Basin.

  12. Efficacy of exclosures in conserving local shrub biodiversity in xeric sandy grassland, Inner Mongolia, China

    Science.gov (United States)

    Feng-Rui Li; Zhi-Yu Zhou; Li-Ya Zhao; Ai-Sheng Zhang; Ling-Fen Kang

    2007-01-01

    This study investigated the abundance and frequency of occurrence of all shrub species present in the standing vegetation at four sites, including a 5-year exclosure (protected grassland) and three adjacent unprotected grazing sites that had been subjected to different levels of degradation (light, moderate and severe), in xeric sandy grassland of Inner Mongolia for...

  13. Variation in soil organic carbon within highland grasslands of Langtang National Park, Nepal

    Directory of Open Access Journals (Sweden)

    Keshab Shrestha

    2016-09-01

    Full Text Available Grassland also plays important role in food security. The estimated grassland area in Nepal is about 1.75 million ha. Most of the grassland in Nepal is located in higher elevation above, 2000 meter. The aim of this research is to observe difference in SOC of grassland in different altitude. Soil samples were collected from grasslands of altitude: 1500- 2000m, 2001- 2500m, 2501-3000m, 3001- 3500m and 3501- 4000m. The soil samples were collected at successive depths in each grassland i.e. 0 – 10 cm, 10 – 20 cm and 20 – 30 cm. The maximum SOC was found in grassland at altitude 3001 m- 3500m. The lowest was SOC was found in grassland at altitude 3051m – 4000m. Correlation analysis between altitude and SOC shows that SOC is positively correlated with altitude with correlation coefficient 0.850 (significant at P<0.05 level. But SOC decreases sharply in treeline with negative correlation (Significant at P<0.05.International Journal of Environment Vol.5(3 2016, pp.57-65

  14. Grassland simulation with the LPJmL model : version 3.4.018

    NARCIS (Netherlands)

    Boons-Prins, E.R.

    2010-01-01

    One third of the land surface is covered with natural and cultivated grasslands. Most of these grasslands are intensively or extensively exploited by humans to feed animals. With growing wealth, causing an increase of meat consumption, there is a need to better understand the processes that

  15. Effects of nitrogen fertilization and grazing on the emission of nitrous oxide from grassland

    Energy Technology Data Exchange (ETDEWEB)

    Velthof, G.L.; Brader, A.B.; Oenema, O. [NMI, Dept. of Soil Science and Plant Nutrition, Wageningen Agricultural Univ. (Netherlands)

    1995-11-01

    In the Netherlands, managed grasslands are potentially a large source of nitrous oxide (N{sub 2}O), because of the large nitrogen (N) input and the relatively high ground water levels. To provide insight into the major factors that contribute to N{sub 2}O emission from grassland and to provide quantitative N{sub 2}O emission rates, a monitoring study was carried out on four sites, during March 1992 to March 1994. Fluxes of N{sub 2}O increased after N fertilizer application and grazing, especially during wet conditions. Fluxes were higher from peat soils than from sand and clay soils. Fluxes were low during the winter periods. Total N{sub 2}O losses were 2 to 4.5 times higher on grassland fertilized with 160-460 kg N ha{sup -1} yr{sup -1} than on unfertilized grassland. Losses from grazed grasslands were 1.5 to 3.5 times higher than losses from mown grassland. This study shows that management practice of grassland and soil type are major factors controlling N{sub 2}O emission from grasslands. 2 figs., 3 refs.

  16. 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

  17. Spatial probability models of fire in the desert grasslands of the southwestern USA

    Science.gov (United States)

    Fire is an important driver of ecological processes in semiarid environments; however, the role of fire in desert grasslands of the Southwestern US is controversial and the regional fire distribution is largely unknown. We characterized the spatial distribution of fire in the desert grassland region...

  18. Root biomass and carbon storage in differently managed multispecies temporary grasslands

    DEFF Research Database (Denmark)

    Eriksen, Jørgen; Mortensen, Tine Bloch; Søegaard, Karen

    2012-01-01

    Species-rich grasslands may potentially increase carbon (C) storage in soil, and an experiment was established to investigate C storage in highly productive temporary multi-species grasslands. Plots were established with three mixtures: (1) a herb mixture containing salad burnet (Sanguisorba minor...

  19. Vascular plants and a brief history of the Kiowa and Rita Blanca National Grasslands

    Science.gov (United States)

    Donald L. Hazlett; Michael H. Schiebout; Paulette L. Ford

    2009-01-01

    Administered by the USDA Forest Service, the Kiowa and Rita Blanca National Grasslands occupy 230,000 acres of public land extending from northeastern New Mexico into the panhandles of Oklahoma and Texas. A mosaic of topographic features including canyons, plateaus, rolling grasslands and outcrops supports a diverse flora. Eight hundred twenty six (826) species of...

  20. Spatial patterns of grasses and shrubs in an arid grassland environment

    Science.gov (United States)

    In the Chihuahuan Desert of Mexico and New Mexico, shrub invasion is a common problem, and once-abundant grassland ecosystems are being replaced by shrub-dominated habitat. The spatial arrangement of grasses and shrubs in these arid grasslands can provide better insight into community dynamics and c...

  1. Linear objects impact on grassland degradation in the typical steppe region of China

    NARCIS (Netherlands)

    Li, Suying; Verburg, Peter H.; Lv, Shihai; Gao, Shangyu; Wu, Jingle

    2011-01-01

    Despite growing recognition of the issue of grassland degradation, few regional estimates of linear object impacts on grassland degradation [1]. We presented a methodology for evaluating regional impacts on steppe degradation from linear objects which were two uppermost types, rivers and roads, in

  2. Secondary succession after fire in Imperata grasslands of East Kalimantan Indonesia

    NARCIS (Netherlands)

    Yassir, I.; Kamp, van der J.; Buurman, P.

    2010-01-01

    Regeneration of grassland areas is becoming increasingly important, not only to create new secondary forest and recover the original biodiversity, but also recover for agriculture. We studied an early succession in Imperata grasslands in East Kalimantan, Indonesia, using plots that last burned 3

  3. Potential of endozoochorous seed dispersal by sheep in calcareous grasslands: correlations with seed traits.

    NARCIS (Netherlands)

    Kuiters, A.T.; Huiskes, H.P.J.

    2010-01-01

    Questions: What is the potential of sheep to serve as seed dispersers via ingestion and defecation in calcareous grasslands? Is the presence of viable seeds from dung correlated with specific seed traits? Location: Calcareous grasslands, South Limburg, the Netherlands/Belgium. Methods: Dung samples

  4. Hemiptera community and species responses to grassland sward islets

    OpenAIRE

    Helden, Alvin J.; Dittrich, Alex D. K.

    2016-01-01

    Sward islet is a term that has been used to describe a patch of longer vegetation in a pasture produced by a reduction in cattle grazing around their dung. They are known to affect the abundance and distribution of grassland arthropods. Hemiptera, like other groups, are found in higher densities within islets than the surrounding sward. Does this modify the community composition or is there just a density effect? Evidence from a paired (islets, non-islets) study at an Irish cattle-grazed site...

  5. Organic matter dynamics and N mineralization in grassland soils

    OpenAIRE

    Hassink, J.

    1995-01-01


    The aims of this study are i) to improve our understanding of the interactions between soil texturelsoil structure, soil organic matter, soil biota and mineralization in grassland soils, ii) to develop a procedure that yields soil organic matter fractions that can be determined directly and can be used in soil organic matter models, iii) to develop a model that predicts the long-term dynamics of soil organic matter, iv) to develop a simple model that can be used by farmers and advi...

  6. Mapping spatio-temporal variation of grassland quantity and quality using MERIS data and the PROSAIL model

    NARCIS (Netherlands)

    Si, Y.; Schlerf, M.; Zurita-Milla, R.; Skidmore, A.K.; Wang, T.

    2012-01-01

    Accurate estimates of the quantity and quality of grasslands, as they vary in space and time and from regional to global scales, furthers our understanding of grassland ecosystems. The Medium Resolution Imaging Spectrometer (MERIS) is a promising sensor for measuring and monitoring grasslands due to

  7. 78 FR 65609 - Medicine Bow-Routt National Forests and Thunder Basin National Grassland; Wyoming; Thunder Basin...

    Science.gov (United States)

    2013-11-01

    ... National Grassland; Wyoming; Thunder Basin National Grassland Prairie Dog Amendment Environmental Impact... Cooperating Agencies. No changes to the Proposed Action or Purpose of and Need for Action have been made... alternatives will be analyzed in the Thunder Basin National Grassland Prairie Dog Amendment EIS. The EIS will...

  8. Effect of degradation intensity on grassland ecosystem services in the alpine region of Qinghai-Tibetan Plateau, China.

    Directory of Open Access Journals (Sweden)

    Lu Wen

    Full Text Available The deterioration of alpine grassland has great impact on ecosystem services in the alpine region of Qinghai-Tibetan Plateau. However, the effect of grassland degradation on ecosystem services and the consequence of grassland deterioration on economic loss still remains a mystery. So, in this study, we assessed four types of ecosystem services following the Millennium Ecosystem Assessment classification, along a degradation gradient. Five sites of alpine grassland at different levels of degradation were investigated in Guoluo Prefecture of Qinghai Province, China. The species composition, aboveground biomass, soil total organic carbon (TOC, and soil total nitrogen (TN were tested to evaluate major ecological services of the alpine grassland. We estimated the value of primary production, carbon storage, nitrogen recycling, and plant diversity. The results show the ecosystem services of alpine grassland varied along the degradation gradient. The ecosystem services of degraded grassland (moderate, heavy and severe were all significantly lower than non-degraded grassland. Interestingly, the lightly degraded grassland provided more economic benefit from carbon maintenance and nutrient sequestration compared to non-degraded. Due to the destruction of the alpine grassland, the economic loss associated with decrease of biomass in 2008 was $198/ha. Until 2008, the economic loss caused by carbon emissions and nitrogen loss on severely degraded grassland was up to $8 033/ha and $13 315/ha, respectively. Urgent actions are required to maintain or promote the ecosystem services of alpine grassland in the Qinghai-Tibetan Plateau.

  9. Effect of degradation intensity on grassland ecosystem services in the alpine region of Qinghai-Tibetan Plateau, China.

    Science.gov (United States)

    Wen, Lu; Dong, Shikui; Li, Yuanyuan; Li, Xiaoyan; Shi, Jianjun; Wang, Yanlong; Liu, Demei; Ma, Yushou

    2013-01-01

    The deterioration of alpine grassland has great impact on ecosystem services in the alpine region of Qinghai-Tibetan Plateau. However, the effect of grassland degradation on ecosystem services and the consequence of grassland deterioration on economic loss still remains a mystery. So, in this study, we assessed four types of ecosystem services following the Millennium Ecosystem Assessment classification, along a degradation gradient. Five sites of alpine grassland at different levels of degradation were investigated in Guoluo Prefecture of Qinghai Province, China. The species composition, aboveground biomass, soil total organic carbon (TOC), and soil total nitrogen (TN) were tested to evaluate major ecological services of the alpine grassland. We estimated the value of primary production, carbon storage, nitrogen recycling, and plant diversity. The results show the ecosystem services of alpine grassland varied along the degradation gradient. The ecosystem services of degraded grassland (moderate, heavy and severe) were all significantly lower than non-degraded grassland. Interestingly, the lightly degraded grassland provided more economic benefit from carbon maintenance and nutrient sequestration compared to non-degraded. Due to the destruction of the alpine grassland, the economic loss associated with decrease of biomass in 2008 was $198/ha. Until 2008, the economic loss caused by carbon emissions and nitrogen loss on severely degraded grassland was up to $8 033/ha and $13 315/ha, respectively. Urgent actions are required to maintain or promote the ecosystem services of alpine grassland in the Qinghai-Tibetan Plateau.

  10. Grasslands of Mexico: A perspective on their conservation (Los pastizales del norte de Mexico: Una perspectiva para su conservacion)

    Science.gov (United States)

    Patricia Manzano; Rurik List

    2006-01-01

    Grasslands are areas dominated by grasses and herbs with few or no trees. Grasslands receive too much rain for a desert environment and too little for a forest. Temperate North American grasslands, especially, have undergone changes on a continental level. Their high productivity and fertility, added to their level topography and lack of trees, make them ideal sites...

  11. Historical biome distribution and recent human disturbance shape the diversity of arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Pärtel, Meelis; Öpik, Maarja; Moora, Mari; Tedersoo, Leho; Szava-Kovats, Robert; Rosendahl, Søren; Rillig, Matthias C; Lekberg, Ylva; Kreft, Holger; Helgason, Thorunn; Eriksson, Ove; Davison, John; de Bello, Francesco; Caruso, Tancredi; Zobel, Martin

    2017-10-01

    The availability of global microbial diversity data, collected using standardized metabarcoding techniques, makes microorganisms promising models for investigating the role of regional and local factors in driving biodiversity. Here we modelled the global diversity of symbiotic arbuscular mycorrhizal (AM) fungi using currently available data on AM fungal molecular diversity (small subunit (SSU) ribosomal RNA (rRNA) gene sequences) in field samples. To differentiate between regional and local effects, we estimated species pools (sets of potentially suitable taxa) for each site, which are expected to reflect regional processes. We then calculated community completeness, an index showing the fraction of the species pool present, which is expected to reflect local processes. We found significant spatial variation, globally in species pool size, as well as in local and dark diversity (absent members of the species pool). Species pool size was larger close to areas containing tropical grasslands during the last glacial maximum, which are possible centres of diversification. Community completeness was greater in regions of high wilderness (remoteness from human disturbance). Local diversity was correlated with wilderness and current connectivity to mountain grasslands. Applying the species pool concept to symbiotic fungi facilitated a better understanding of how biodiversity can be jointly shaped by large-scale historical processes and recent human disturbance. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  12. Future productivity and phenology changes in European grasslands for different warming levels: implications for grassland management and carbon balance

    OpenAIRE

    Chang, Jinfeng; Ciais, Philippe; Viovy, Nicolas; Soussana, Jean-Fran?ois; Klumpp, Katja; Sultan, Benjamin

    2017-01-01

    Background Europe has warmed more than the global average (land and ocean) since pre-industrial times, and is also projected to continue to warm faster than the global average in the twenty-first century. According to the climate models ensemble projections for various climate scenarios, annual mean temperature of Europe for 2071?2100 is predicted to be 1?5.5??C higher than that for 1971?2000. Climate change and elevated CO2 concentration are anticipated to affect grassland management and liv...

  13. Plant litter dynamics in the forest-stream interface: precipitation is a major control across tropical biomes.

    Science.gov (United States)

    Tonin, Alan M; Gonçalves, José F; Bambi, Paulino; Couceiro, Sheyla R M; Feitoza, Lorrane A M; Fontana, Lucas E; Hamada, Neusa; Hepp, Luiz U; Lezan-Kowalczuk, Vânia G; Leite, Gustavo F M; Lemes-Silva, Aurea L; Lisboa, Leonardo K; Loureiro, Rafael C; Martins, Renato T; Medeiros, Adriana O; Morais, Paula B; Moretto, Yara; Oliveria, Patrícia C A; Pereira, Evelyn B; Ferreira, Lidiane P; Pérez, Javier; Petrucio, Mauricio M; Reis, Deusiano F; S Rezende, Renan; Roque, Nadia; Santos, Luiz E P; Siegloch, Ana E; Tonello, Gabriela; Boyero, Luz

    2017-09-07

    Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even though the tropics occupy 40% of the Earth's land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Amazon forest and Cerrado savanna), predicting major differences among biomes in relation to temperature and precipitation regimes. Precipitation explained most of litter inputs and storage, which were generally higher in more humid biomes (litterfall: 384, 422 and 308 g m -2 y -1 , storage: 55, 113 and 38 g m -2 , on average in Atlantic forest, Amazon and Cerrado, respectively). Temporal dynamics varied across biomes in relation to precipitation and temperature, with uniform litter inputs but seasonal storage in Atlantic forest streams, seasonal inputs in Amazon and Cerrado streams, and aseasonal storage in Amazon streams. Our findings suggest that litter dynamics vary greatly within the tropics, but point to the major role of precipitation, which contrasts with the main influence of temperature in temperate areas.

  14. Adapting the Biome-BGC Model to New Zealand Pastoral Agriculture: Climate Change and Land-Use Change

    Science.gov (United States)

    Keller, E. D.; Baisden, W. T.; Timar, L.

    2011-12-01

    We have adapted the Biome-BGC model to make climate change and land-use scenario estimates of New Zealand's pasture production in 2020 and 2050, with comparison to a 2005 baseline. We take an integrated modelling approach with the aim of enabling the model's use for policy assessments across broadly related issues such as climate change mitigation and adaptation, land-use change, and greenhouse gas projections. The Biome-BGC model is a biogeochemical model that simulates carbon, water, and nitrogen cycles in terrestrial ecosystems. We introduce two new 'ecosystems', sheep/beef and dairy pasture, within the existing structure of the Biome-BGC model and calibrate its ecophysiological parameters against pasture clipping data from diverse sites around New Zealand to form a baseline estimate of total New Zealand pasture production. Using downscaled AR4 climate projections, we construct mid- and upper-range climate change scenarios in 2020 and 2050. We produce land-use change scenarios in the same years by combining the Biome-BGC model with the Land Use in Rural New Zealand (LURNZ) model. The LURNZ model uses econometric approaches to predict future land-use change driven by changes in net profits driven by expected pricing, including the introduction of an emission trading system. We estimate the relative change in national pasture production from our 2005 baseline levels for both sheep/beef and dairy systems under each scenario.

  15. Scaling net ecosystem production and net biome production over a heterogeneous region in the Western United States

    Science.gov (United States)

    D.P. Turner; W.D. Ritts; B.E. Law; W.B. Cohen; Z. Yan; T. Hudiburg; J.L. Campbell; M. Duane

    2007-01-01

    Bottom-up scaling of net ecosystem production (NEP) and net biome production (NBP) was used to generate a carbon budget for a large heterogeneous region (the state of Oregon, 2.5x105 km2 ) in the Western United States. Landsat resolution (30 m) remote sensing provided the basis for mapping land cover and disturbance history...

  16. A remarkable finding that suggests the existence of a new groundwater biome based on chemoautotrophic resources, named

    Directory of Open Access Journals (Sweden)

    Ştefan Negrea

    2009-01-01

    Full Text Available An important work of subterranean biology, signed by Francis Dov Por, Ophel: a groundwater biome based on chemoautotrophic resources. The global significance of the Ayyalon cave finds, Israel is presented and discussed in the present paper. The subject is a remarkable discovery suggesting the existence of a new aquatic subterranean biome autonomous energy based the author calls Ophel, the Hebrew word for “darkness” and “netherworld”. For F.D. Por, this biome links different marine chemosynthetic ecosystems in a global biospheric entity. Finally, F.D. POR hypothesizes on the existence of three overlapped biospheres: the bacteriosphere in the depths of the planet’s crust, which does not require light or oxygen; the aphotic, subterranean deuterobiosphere, formed of bacterial chemosynthesis based eukaryotes and limited-supplied dissolved oxygen from above-ground; the above-ground eubiosphere, based on aerobic photosynthesis. I would like to emphasize that, at my suggestion, Prof. Dr. F.D. Por participated at the 18th International Symposium of Biospeleology from Cluj-Napoca (Romania at 10th to 15th July 2006 where he mentioned for the first time orally some data on the Ayyalon Cave and the Ophel biome.

  17. Physiology of Saccharomyces cerevisiae strains isolated from Brazilian biomes: new insights into biodiversity and industrial applications

    DEFF Research Database (Denmark)

    Beato, Felipe B.; Bergdahl, Basti; Rosa, Carlos A.

    2016-01-01

    Fourteen indigenous Saccharomyces cerevisiae strains isolated from the barks of three tree species located in the Atlantic Rain Forest and Cerrado biomes in Brazil were genetically and physiologically compared to laboratory strains and to strains from the Brazilian fuel ethanol industry. Although...

  18. Environmental history of the dry forest biome of Guerrero, Mexico, and human impact during the last c. 2700 years

    NARCIS (Netherlands)

    Berrio, J.C.; Hooghiemstra, H.; van Geel, B.; Ludlow-Wiegers, B.

    2006-01-01

    Two lake sediment cores from Madre del Sur mountain range, Guerrero State, west-central Mexico were studied to examine the past dynamics of the dry forest biome. Pollen, spores of coprophilous fungi, cyanobacteria and lithological changes are presented. The 390-cm Tixtla core (17°30′N, 99°24′W, 1400

  19. A method to determine warm and cool steppe biomes from pollen data; application to the Mediterranean and Kazakhstan regions

    NARCIS (Netherlands)

    Tarasov, PE; Cheddadi, R; Guiot, J; Bottema, S; Peyron, O; Belmonte, J; Ruiz-Sanchez, [No Value; Saadi, F; Brewer, S

    1998-01-01

    An objective method for the assignment of pollen spectra to appropriate biomes has been published recently. The aim of this paper is to improve the distinction between warm and cool steppes, thus refining vegetation and climate reconstruction, particularly during the Last Glacial Maximum. A set of

  20. Pennsylvanian coniferopsid forests in sabkha facies reveal the nature of seasonal tropical biome

    Science.gov (United States)

    Falcon-Lang, H. J.; Jud, N.A.; John, Nelson W.; DiMichele, W.A.; Chaney, D.S.; Lucas, S.G.

    2011-01-01

    Pennsylvanian fossil forests are known from hundreds of sites across tropical Pangea, but nearly all comprise remains of humid Coal Forests. Here we report a unique occurrence of seasonally dry vegetation, preserved in growth position along >5 km of strike, in the Pennsylvanian (early Kasimovian, Missourian) of New Mexico (United States). Analyses of stump anatomy, diameter, and spatial density, coupled with observations of vascular traces and associated megaflora, show that this was a deciduous, mixed-age, coniferopsid woodland (~100 trees per hectare) with an open canopy. The coniferopsids colonized coastal sabkha facies and show tree rings, confirming growth under seasonally dry conditions. Such woodlands probably served as the source of coniferopsids that replaced Coal Forests farther east in central Pangea during drier climate phases. Thus, the newly discovered woodland helps unravel biome-scale vegetation dynamics and allows calibration of climate models. ?? 2011 Geological Society of America.

  1. The global extent and determinants of savanna and forest as alternative biome states.

    Science.gov (United States)

    Staver, A Carla; Archibald, Sally; Levin, Simon A

    2011-10-14

    Theoretically, fire-tree cover feedbacks can maintain savanna and forest as alternative stable states. However, the global extent of fire-driven discontinuities in tree cover is unknown, especially accounting for seasonality and soils. We use tree cover, climate, fire, and soils data sets to show that tree cover is globally discontinuous. Climate influences tree cover globally but, at intermediate rainfall (1000 to 2500 millimeters) with mild seasonality (less than 7 months), tree cover is bimodal, and only fire differentiates between savanna and forest. These may be alternative states over large areas, including parts of Amazonia and the Congo. Changes in biome distributions, whether at the cost of savanna (due to fragmentation) or forest (due to climate), will be neither smooth nor easily reversible.

  2. BOREAS RSS-8 BIOME-BGC SSA Simulation of Annual Water and Carbon Fluxes

    Science.gov (United States)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Kimball, John

    2000-01-01

    The BOREAS RSS-8 team performed research to evaluate the effect of seasonal weather and landcover heterogeneity on boreal forest regional water and carbon fluxes using a process-level ecosystem model, BIOME-BGC, coupled with remote sensing-derived parameter maps of key state variables. This data set contains derived maps of landcover type and crown and stem biomass as model inputs to determine annual evapotranspiration, gross primary production, autotrophic respiration, and net primary productivity within the BOREAS SSA-MSA, at a 30-m spatial resolution. Model runs were conducted over a 3-year period from 1994-1996; images are provided for each of those years. The data are stored in binary image format. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  3. Multiple nutrient stresses at intersecting Pacific Ocean biomes detected by protein biomarkers.

    Science.gov (United States)

    Saito, Mak A; McIlvin, Matthew R; Moran, Dawn M; Goepfert, Tyler J; DiTullio, Giacomo R; Post, Anton F; Lamborg, Carl H

    2014-09-05

    Marine primary productivity is strongly influenced by the scarcity of required nutrients, yet our understanding of these nutrient limitations is informed by experimental observations with sparse geographical coverage and methodological limitations. We developed a quantitative proteomic method to directly assess nutrient stress in high-light ecotypes of the abundant cyanobacterium Prochlorococcus across a meridional transect in the central Pacific Ocean. Multiple peptide biomarkers detected widespread and overlapping regions of nutritional stress for nitrogen and phosphorus in the North Pacific Subtropical Gyre and iron in the equatorial Pacific. Quantitative protein analyses demonstrated simultaneous stress for these nutrients at biome interfaces. This application of proteomic biomarkers to diagnose ocean metabolism demonstrated Prochlorococcus actively and simultaneously deploying multiple biochemical strategies for low-nutrient conditions in the oceans. Copyright © 2014, American Association for the Advancement of Science.

  4. Overview on Environmental Comprehensive Management System Established in Imitation of Biome

    Institute of Scientific and Technical Information of China (English)

    李如燕; 孙可伟

    2004-01-01

    Environmental comprehensive management system, called "the bionic community", can be established in imitation of biome, which can transform the wastes generated in a certain field into the raw materials of other field. The establishment of the bionic community includes two aspects, i.e. , the matching technique and the management system. The main matching technique is the preparation of composite materials made of various wastes.This new kind of material can be divided into four types: polymer matrix, silicate matrix, metal matrix and carbon matrix (or ceramic matrix). The environmental comprehensive management system is formed by organizing a transtrades joint-management business entity with the products of composite material made of wastes at the core.

  5. Biométria de frutos e sementes de Luetzelburgia auriculata (Allemão Ducke

    Directory of Open Access Journals (Sweden)

    Roberto Ferreira Barroso

    2016-12-01

    Full Text Available A Caatinga apresenta uma grande diversidade de espécies vegetais, dentre elas Luetzelburgia auriculata é uma das espécies predominantes no bioma, desempenhando papel fundamental para o ecossistema local. Este trabalho objetivou descrever as características biométricas de frutos e sementes de Luetzelburgia auriculata.  Para a descrição das características da semente foram coletados 200 frutos e 200 sementes de plantas nativas do município de Santa Helena, Paraíba. As amostras foram encaminhadas ao Laboratório de Nutrição Mineral de Plantas do Centro de Saúde e Tecnologia Rural de Universidade Federal de Campina Grande para a realização das devidas aferições biométricas. Os frutos foram analisado pelo comprimento, espessura superior, mediana e inferior; largura superior, mediana e inferior. Para as sementes, foram analisados comprimento, espessura e a largura. Verificou-se que o comprimento dos frutos variou de 50,7 a 98,2 cm, a espessura de 6,00 a 17 mm e largura variando de 12,4 a 21,8 mm. Em relação às sementes, 46% se enquadraram na classe de comprimento com intervalo de 19,9 a 20,8 mm. A espécie Luetzelburgia auriculata apresentam variabilidade nas características biométricas de frutos e sementesBiometrics of fruit and seeds of Luetzelburgia auriculata (Allemão DuckeAbstract: The Caatinga presents a great diversity of plant species, among them the woodpecker (Luetzelburgia auriculata (Allemao Ducke. is one of the predominant species in the biome, playing a fundament al role for the local ecosystem. This work aimed to describe the biometric characteristics of fruits and seeds of Pau de Pedra. For the description of the characteristics of the Luetzelburgia auriculata (Allemão Ducke seed, 200 fruits and 200 seeds of native plants of the municipality of Santa Helena, Paraíba state were collected for biometry and seed mass. Afterwards they were packed in plastic bags and properly identified and taken to Laboratório de

  6. Autenticación mediante parámetros biométricos

    OpenAIRE

    Pastor Navarro, Ricard

    2017-01-01

    En les pàgines següents s’explicarà el procés seguit per la realització d’aquest treball de final de grau, en el que es pretén substituir, en un programa de gestió de contrasenyes, la contrasenya mestre per paràmetres biomètrics, concretament el reconeixement facial. Per a complir amb aquest objectiu s’utilitzaran alguns algoritmes de visió per computador extrets de les llibreries de OpenCV. El sistema final agafarà imatges de l’usuari i fent la comprovació del usuari decidint si ha de donar ...

  7. Genetic Divergence in Eucalyptus camaldulensis Progenies in the Savanna Biome in Mato Grosso, Brazil.

    Directory of Open Access Journals (Sweden)

    Reginaldo Brito da Costa

    Full Text Available Assessing the parental genetic differences and their subsequent prediction of progeny performance is an important first step to assure the efficiency of any breeding program. In this study, we estimate the genetic divergence in Eucalyptus camaldulensis based on the morphological traits of 132 progenies grown in a savanna biome. Thus, a field experiment was performed using a randomized block design and five replications to compare divergences in total height, commercial height, diameter at breast height, stem form and survival rate at 48 months. Tocher's clustering method was performed using the Mahalanobis and Euclidian distances. The Mahalanobis distance seemed more reliable for the assessed parameters and clustered all of the progenies into fourteen major groups. The most similar progenies (86 accessions were clustered into Group I, while the most dissimilar (1 progeny represented Group XIV. The divergence analysis indicated that promising crosses could be made between progenies allocated in different groups for high genetic divergence and for favorable morphological traits.

  8. Tundra biome research in Alaska: the structure and function of cold-dominated ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.; West, G.C.

    1970-11-01

    The objective of the Tundra Biome Program is to acquire a basic understanding of tundra, both alpine and arctic, and taiga. Collectively these are referred to as the cold-dominated ecosystems. The program's broad objectives are threefold: To develop a predictive understanding of how the wet arctic tundra ecosystem operates, particularly as exemplified in the Barrow, Alaska, area; to obtain the necessary data base from the variety of cold-dominated ecosystem types represented in the United States, so that their behavior can be modeled and simulated, and the results compared with similar studies underway in other circumpolar countries; to bring basic environmental knowledge to bear on problems of degradation, maintenance, and restoration of the temperature-sensitive and cold-dominated tundra/taiga ecosystems. (GRA)

  9. Microbial Community Profile and Water Quality in a Protected Area of the Caatinga Biome.

    Science.gov (United States)

    Lopes, Fabyano Alvares Cardoso; Catão, Elisa Caldeira Pires; Santana, Renata Henrique; Cabral, Anderson de Souza; Paranhos, Rodolfo; Rangel, Thiago Pessanha; de Rezende, Carlos Eduardo; Edwards, Robert A; Thompson, Cristiane C; Thompson, Fabiano L; Kruger, Ricardo Henrique

    2016-01-01

    The Caatinga is a semi-arid biome in northeast Brazil. The Paraguaçú River is located in the Caatinga biome, and part of its course is protected by the National Park of Chapada Diamantina (PNCD). In this study we evaluated the effect of PNCD protection on the water quality and microbial community diversity of this river by analyzing water samples obtained from points located inside and outside the PNCD in both wet and dry seasons. Results of water quality analysis showed higher levels of silicate, ammonia, particulate organic carbon, and nitrite in samples from the unprotected area compared with those from protected areas. Pyrosequencing of the 16S rRNA genes revealed that Burkholderiales was abundant in samples from all three sites during both seasons and was represented primarily by the genus Polynucleobacter and members of the Comamonadaceae family (e.g., genus Limnohabitans). During the dry season, the unprotected area showed a higher abundance of Flavobacterium sp. and Arthrobacter sp., which are frequently associated with the presence and/or degradation of arsenic and pesticide compounds. In addition, genes that appear to be related to agricultural impacts on the environment, as well as those involved in arsenic and cadmium resistance, copper homeostasis, and propanediol utilization, were detected in the unprotected areas by metagenomic sequencing. Although PNCD protection improves water quality, agricultural activities around the park may affect water quality within the park and may account for the presence of bacteria capable of pesticide degradation and assimilation, evidencing possible anthropogenic impacts on the Caatinga.

  10. A dated phylogeny and collection records reveal repeated biome shifts in the African genus Coccinia (Cucurbitaceae).

    Science.gov (United States)

    Holstein, Norbert; Renner, Susanne S

    2011-01-26

    Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated habitat fragmentation, on diversification in the mostly sub-Saharan cucurbit genus Coccinia, which has 27 species in a broad range of biota from semi-arid habitats to mist forests. Species limits were inferred from morphology, and nuclear and plastid DNA sequence data, using multiple individuals for the widespread species. Climatic tolerances were assessed from the occurrences of 1189 geo-referenced collections and WorldClim variables. Nuclear and plastid gene trees included 35 or 65 accessions, representing up to 25 species. The data revealed four species groups, one in southern Africa, one in Central and West African rain forest, one widespread but absent from Central and West African rain forest, and one that occurs from East Africa to southern Africa. A few individuals are differently placed in the plastid and nuclear (LFY) trees or contain two ITS sequence types, indicating hybridization. A molecular clock suggests that the diversification of Coccinia began about 6.9 Ma ago, with most of the extant species diversity dating to the Pliocene. Ancestral biome reconstruction reveals six switches between semi-arid habitats, woodland, and forest, and members of several species pairs differ significantly in their tolerance of different precipitation regimes. The most surprising findings of this study are the frequent biome shifts (in a relatively small clade) over just 6 - 7 million years and the limited diversification during and since the Pleistocene. Pleistocene climate oscillations may have been too rapid or too shallow for full reproductive barriers to develop among fragmented populations of Coccinia, which would explain the apparently still ongoing hybridization between certain species. Steeper ecological gradients in East Africa and

  11. Trans-biome diversity in Australian grass-specialist lizards (Diplodactylidae: Strophurus).

    Science.gov (United States)

    Laver, Rebecca J; Nielsen, Stuart V; Rosauer, Dan F; Oliver, Paul M

    2017-10-01

    Comparisons of biodiversity patterns within lineages that occur across major climate gradients and biomes, can provide insights into the relative roles that lineage history, landscape and climatic variation, and environmental change have played in shaping regional biotas. In Australia, while there has been extensive research into the origins and patterns of diversity in the Australian Arid Zone (AAZ), how diversity is distributed across this biome and the Australian Monsoonal Tropics (AMT) to the north, has been less studied. We compared the timing and patterns of diversification across this broad aridity gradient in a clade of lizards (Strophurus: phasmid geckos) that only occur in association with a unique Australian radiation of sclerophyllous grasses (Triodia: spinifex). Our results indicate that overall genetic diversity is much higher, older and more finely geographically structured within the AMT, including distantly related clades endemic to the sandstone escarpments of the Kimberley and Arnhem Plateau. Niche modelling analyses also suggest that the distribution of taxa in the AMT is more strongly correlated with variation in topographic relief than in the AAZ. The two broad patterns that we recovered - (i) lineage endemism increases as latitude decreases, and (ii) endemism is tightly correlated to rocky regions - parallel and corroborate other recent studies of habitat generalists and specialised saxicoline lineages occurring across these same regions. Early Miocene diversification estimates also suggest that, soon after Triodia grasses colonised Australia and began to diversify in the Miocene, phasmid geckos with Gondwanan ancestry shifted into these grasses, and have subsequently remained closely associated with this unique vegetation type. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Biome-scale nitrogen fixation strategies selected by climatic constraints on nitrogen cycle.

    Science.gov (United States)

    Sheffer, Efrat; Batterman, Sarah A; Levin, Simon A; Hedin, Lars O

    2015-11-23

    Dinitrogen fixation by plants (in symbiosis with root bacteria) is a major source of new nitrogen for land ecosystems(1). A long-standing puzzle(2) is that trees capable of nitrogen fixation are abundant in nitrogen-rich tropical forests, but absent or restricted to early successional stages in nitrogen-poor extra-tropical forests. This biome-scale pattern presents an evolutionary paradox(3), given that the physiological cost(4) of nitrogen fixation predicts the opposite pattern: fixers should be out-competed by non-fixers in nitrogen-rich conditions, but competitively superior in nitrogen-poor soils. Here we evaluate whether this paradox can be explained by the existence of different fixation strategies in tropical versus extra-tropical trees: facultative fixers (capable of downregulating fixation(5,6) by sanctioning mutualistic bacteria(7)) are common in the tropics, whereas obligate fixers (less able to downregulate fixation) dominate at higher latitudes. Using a game-theoretic approach, we assess the ecological and evolutionary conditions under which these fixation strategies emerge, and examine their dependence on climate-driven differences in the nitrogen cycle. We show that in the tropics, transient soil nitrogen deficits following disturbance and rapid tree growth favour a facultative strategy and the coexistence of fixers and non-fixers. In contrast, sustained nitrogen deficits following disturbance in extra-tropical forests favour an obligate fixation strategy, and cause fixers to be excluded in late successional stages. We conclude that biome-scale differences in the abundance of nitrogen fixers can be explained by the interaction between individual plant strategies and climatic constraints on the nitrogen cycle over evolutionary time.

  13. A dated phylogeny and collection records reveal repeated biome shifts in the African genus Coccinia (Cucurbitaceae

    Directory of Open Access Journals (Sweden)

    Renner Susanne S

    2011-01-01

    Full Text Available Abstract Background Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated habitat fragmentation, on diversification in the mostly sub-Saharan cucurbit genus Coccinia, which has 27 species in a broad range of biota from semi-arid habitats to mist forests. Species limits were inferred from morphology, and nuclear and plastid DNA sequence data, using multiple individuals for the widespread species. Climatic tolerances were assessed from the occurrences of 1189 geo-referenced collections and WorldClim variables. Results Nuclear and plastid gene trees included 35 or 65 accessions, representing up to 25 species. The data revealed four species groups, one in southern Africa, one in Central and West African rain forest, one widespread but absent from Central and West African rain forest, and one that occurs from East Africa to southern Africa. A few individuals are differently placed in the plastid and nuclear (LFY trees or contain two ITS sequence types, indicating hybridization. A molecular clock suggests that the diversification of Coccinia began about 6.9 Ma ago, with most of the extant species diversity dating to the Pliocene. Ancestral biome reconstruction reveals six switches between semi-arid habitats, woodland, and forest, and members of several species pairs differ significantly in their tolerance of different precipitation regimes. Conclusions The most surprising findings of this study are the frequent biome shifts (in a relatively small clade over just 6 - 7 million years and the limited diversification during and since the Pleistocene. Pleistocene climate oscillations may have been too rapid or too shallow for full reproductive barriers to develop among fragmented populations of Coccinia, which would explain the apparently still ongoing hybridization between certain

  14. Soil, water, and nutrient losses from management alternatives for degraded pasture in Brazilian Atlantic Rainforest biome.

    Science.gov (United States)

    Rocha Junior, Paulo Roberto da; Andrade, Felipe Vaz; Mendonça, Eduardo de Sá; Donagemma, Guilherme Kangussú; Fernandes, Raphael Bragança Alves; Bhattharai, Rabin; Kalita, Prasanta Kumar

    2017-04-01

    The objective of this study was to evaluate sediment, water and nutrient losses from different pasture managements in the Atlantic Rainforest biome. A field study was carried out in Alegre Espiríto Santo, Brazil, on a Xanthic Ferralsol cultivated with braquiaria (Brachiaria brizantha). The six pasture managements studied were: control (CON), chisel (CHI), fertilizer (FER), burned (BUR), plowing and harrowing (PH), and integrated crop-livestock (iCL). Runoff and sediment samples were collected and analyzed for calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P) and organic carbon contents. Soil physical attributes and above and below biomass were also evaluated. The results indicated that higher water loss was observed for iCL (129.90mm) and CON (123.25mm) managements, and the sediment losses were higher for CON (10.24tha -1 ) and BUR (5.20tha -1 ) managements when compared to the other managements. Majority of the nutrients losses occurred in dissolved fraction (99% of Ca, 99% of Mg, 96% of K, and 65% of P), whereas a significant fraction of organic carbon (80%) loss occurred in a particulate form. Except for P, other nutrients (Ca, Mg and K) and organic carbon losses were higher in coarse sediment compared to fine sediment. The greater losses of sediment, organic carbon, and nutrients were observed for CON followed by BUR management (plosses from various practices, to reduce pasture degradation, farmers should adopt edaphic practices by applying lime and fertilize to improve pasture growth and soil cover, and reducing soil erosion in the hilly Brazilian Atlantic Rainforest biome. Copyright © 2016. Published by Elsevier B.V.

  15. Nitrogen acquisition by plants and microorganisms in a temperate grassland.

    Science.gov (United States)

    Liu, Qianyuan; Qiao, Na; Xu, Xingliang; Xin, Xiaoping; Han, Jessie Yc; Tian, Yuqiang; Ouyang, Hua; Kuzyakov, Yakov

    2016-03-10

    Nitrogen (N) limitation is common in most terrestrial ecosystems, often leading to strong competition between microorganisms and plants. The mechanisms of niche differentiation to reduce this competition remain unclear. Short-term (15)N experiments with NH4(+), NO3(-), and glycine were conducted in July, August and September in a temperate grassland to evaluate the chemical, spatial and temporal niche differentiation by competition between plants and microorganisms for N. Microorganisms preferred NH4(+) and NO3(-), while plants preferred NO3(-). Both plants and microorganisms acquired more N in August and September than in July. The soil depth had no significant effects on microbial uptake, but significantly affected plant N uptake. Plants acquired 67% of their N from the 0-5 cm soil layer and 33% from the 5-15 cm layer. The amount of N taken up by microorganisms was at least seven times than plants. Although microorganisms efficiently compete for N with plants, the competition is alleviated through chemical partitioning mainly in deeper soil layer. In the upper soil layer, neither chemical nor temporal niche separation is realized leading to strong competition between plants and microorganisms that modifies N dynamics in grasslands.

  16. BETA DIVERSITY AND COMMUNITY DIFFERENTIATION IN DRY PERENNIAL SAND GRASSLANDS

    Directory of Open Access Journals (Sweden)

    E. KOVACS-LANG

    2011-01-01

    Full Text Available The spatial variability of species composition was studied in perennial sand grasslands in Hungary at multiple scales. Three sites were compared along an aridity gradient. Existing differences in climate along this ca. 200 km gradient correspond to regional climate changes predicted for the next 20-30 years. Six stands of Festucetum vaginatae grasslands were selected at each site within 400 x 1200 m areas for representing the coarse-scale within-site heterogeneity. Fine-scale compositional heterogeneity of vegetation within stands was sampled by recording the presence of species along 52 m long circular belt transects of 1040 units of 5 cm x 5 cm contiguous microquadrats. This sampling design enabled us to study the patterns of species combinations at a wide range of scales. The highest variability of plant species combinations appeared at very fine scales, between 10 cm and 25 cm. Differences in beta diversity along the gradient were scale-dependent. We found a decreasing trend of beta diversity with increasing aridity at fine scale, and on the contrary, an increasing trend at landscape scale. We conclude that the major trend of the vegetation differentiation due to aridity is the decrease of compositional variability at fine-scale accompanied by a coarse-scale diversification.

  17. Weathering controls on mechanisms of carbon storage in grassland soils

    Science.gov (United States)

    Masiello, C.A.; Chadwick, O.A.; Southon, J.; Torn, M.S.; Harden, J.W.

    2004-01-01

    On a sequence of soils developed under similar vegetation, temperature, and precipitation conditions, but with variations in mineralogical properties, we use organic carbon and 14C inventories to examine mineral protection of soil organic carbon. In these soils, 14C data indicate that the creation of slow-cycling carbon can be modeled as occurring through reaction of organic ligands with Al3+ and Fe3+ cations in the upper horizons, followed by sorption to amorphous inorganic Al compounds at depth. Only one of these processes, the chelation Al3+ and Fe3+ by organic ligands, is linked to large carbon stocks. Organic ligands stabilized by this process traverse the soil column as dissolved organic carbon (both from surface horizons and root exudates). At our moist grassland site, this chelation and transport process is very strongly correlated with the storage and long-term stabilization of soil organic carbon. Our 14C results show that the mechanisms of organic carbon transport and storage at this site follow a classic model previously believed to only be significant in a single soil order (Spodosols), and closely related to the presence of forests. The presence of this process in the grassland Alfisol, Inceptisol, and Mollisol soils of this chronosequence suggests that this process is a more significant control on organic carbon storage than previously thought. Copyright 2004 by the American Geophysical Union.

  18. The role of plant functional trade-offs for biodiversity changes and biome shifts under scenarios of global climatic change

    Directory of Open Access Journals (Sweden)

    B. Reu

    2011-05-01

    Full Text Available The global geographic distribution of biodiversity and biomes is determined by species-specific physiological tolerances to climatic constraints. Current vegetation models employ empirical bioclimatic relationships to predict present-day vegetation patterns and to forecast biodiversity changes and biome shifts under climatic change. In this paper, we consider trade-offs in plant functioning and their responses under climatic changes to forecast and explain changes in plant functional richness and shifts in biome geographic distributions.

    The Jena Diversity model (JeDi simulates plant survival according to essential plant functional trade-offs, including ecophysiological processes such as water uptake, photosynthesis, allocation, reproduction and phenology. We use JeDi to quantify changes in plant functional richness and biome shifts between present-day and a range of possible future climates from two SRES emission scenarios (A2 and B1 and seven global climate models using metrics of plant functional richness and functional identity.

    Our results show (i a significant loss of plant functional richness in the tropics, (ii an increase in plant functional richness at mid and high latitudes, and (iii a pole-ward shift of biomes. While these results are consistent with the findings of empirical approaches, we are able to explain them in terms of the plant functional trade-offs involved in the allocation, metabolic and reproduction strategies of plants. We conclude that general aspects of plant physiological tolerances can be derived from functional trade-offs, which may provide a useful process- and trait-based alternative to bioclimatic relationships. Such a mechanistic approach may be particularly relevant when addressing vegetation responses to climatic changes that encounter novel combinations of climate parameters that do not exist under contemporary climate.

  19. The GAAS metagenomic tool and its estimations of viral and microbial average genome size in four major biomes.

    Science.gov (United States)

    Angly, Florent E; Willner, Dana; Prieto-Davó, Alejandra; Edwards, Robert A; Schmieder, Robert; Vega-Thurber, Rebecca; Antonopoulos, Dionysios A; Barott, Katie; Cottrell, Matthew T; Desnues, Christelle; Dinsdale, Elizabeth A; Furlan, Mike; Haynes, Matthew; Henn, Matthew R; Hu, Yongfei; Kirchman, David L; McDole, Tracey; McPherson, John D; Meyer, Folker; Miller, R Michael; Mundt, Egbert; Naviaux, Robert K; Rodriguez-Mueller, Beltran; Stevens, Rick; Wegley, Linda; Zhang, Lixin; Zhu, Baoli; Rohwer, Forest

    2009-12-01

    Metagenomic studies characterize both the composition and diversity of uncultured viral and microbial communities. BLAST-based comparisons have typically been used for such analyses; however, sampling biases, high percentages of unknown sequences, and the use of arbitrary thresholds to find significant similarities can decrease the accuracy and validity of estimates. Here, we present Genome relative Abundance and Average Size (GAAS), a complete software package that provides improved estimates of community composition and average genome length for metagenomes in both textual and graphical formats. GAAS implements a novel methodology to control for sampling bias via length normalization, to adjust for multiple BLAST similarities by similarity weighting, and to select significant similarities using relative alignment lengths. In benchmark tests, the GAAS method was robust to both high percentages of unknown sequences and to variations in metagenomic sequence read lengths. Re-analysis of the Sargasso Sea virome using GAAS indicated that standard methodologies for metagenomic analysis may dramatically underestimate the abundance and importance of organisms with small genomes in environmental systems. Using GAAS, we conducted a meta-analysis of microbial and viral average genome lengths in over 150 metagenomes from four biomes to determine whether genome lengths vary consistently between and within biomes, and between microbial and viral communities from the same environment. Significant differences between biomes and within aquatic sub-biomes (oceans, hypersaline systems, freshwater, and microbialites) suggested that average genome length is a fundamental property of environments driven by factors at the sub-biome level. The behavior of paired viral and microbial metagenomes from the same environment indicated that microbial and viral average genome sizes are independent of each other, but indicative of community responses to stressors and environmental conditions.

  20. The GAAS metagenomic tool and its estimations of viral and microbial average genome size in four major biomes.

    Directory of Open Access Journals (Sweden)

    Florent E Angly

    2009-12-01

    Full Text Available Metagenomic studies characterize both the composition and diversity of uncultured viral and microbial communities. BLAST-based comparisons have typically been used for such analyses; however, sampling biases, high percentages of unknown sequences, and the use of arbitrary thresholds to find significant similarities can decrease the accuracy and validity of estimates. Here, we present Genome relative Abundance and Average Size (GAAS, a complete software package that provides improved estimates of community composition and average genome length for metagenomes in both textual and graphical formats. GAAS implements a novel methodology to control for sampling bias via length normalization, to adjust for multiple BLAST similarities by similarity weighting, and to select significant similarities using relative alignment lengths. In benchmark tests, the GAAS method was robust to both high percentages of unknown sequences and to variations in metagenomic sequence read lengths. Re-analysis of the Sargasso Sea virome using GAAS indicated that standard methodologies for metagenomic analysis may dramatically underestimate the abundance and importance of organisms with small genomes in environmental systems. Using GAAS, we conducted a meta-analysis of microbial and viral average genome lengths in over 150 metagenomes from four biomes to determine whether genome lengths vary consistently between and within biomes, and between microbial and viral communities from the same environment. Significant differences between biomes and within aquatic sub-biomes (oceans, hypersaline systems, freshwater, and microbialites suggested that average genome length is a fundamental property of environments driven by factors at the sub-biome level. The behavior of paired viral and microbial metagenomes from the same environment indicated that microbial and viral average genome sizes are independent of each other, but indicative of community responses to stressors and

  1. Understanding of Grassland Ecosystems under Climate Change and Economic Development Pressures in the Mongolia Plateau

    Science.gov (United States)

    Qi, J.; Chen, J.; Shan, P.; Pan, X.; Wei, Y.; Wang, M.; Xin, X.

    2011-12-01

    The land use and land cover change, especially in the form of grassland degradation, in the Mongolian Plateau, exhibited a unique spatio-temporal pattern that is a characteristic of a mixed stress from economic development and climate change of the region. The social dimension of the region played a key role in shaping the landscape and land use change, including the cultural clashes with economic development, conflicts between indigenous people and business ventures, and exogenous international influences. Various research projects have been conducted in the region to focus on physical degradation of grasslands and/or on economic development but there is a lack of understanding how the social and economic dimensions interact with grassland ecosystems and changes. In this talk, a synthesis report was made based on the most recent workshop held in Hohhot, Inner Mongolia, of China, that specifically focused on climate change and grassland ecosystems. The report analyzed the degree of grassland degradation, its climate and social drivers, and coupling nature of economic development and conservation of traditional grassland values. The goal is to fully understand the socio-ecological-economic interactions that together shape the trajectory of the grassland ecosystems in the Mongolia Plateau.

  2. Impact of Climate Change on Temperate and Alpine Grasslands in China during 1982–2006

    Directory of Open Access Journals (Sweden)

    Xiangjin Shen

    2015-01-01

    Full Text Available Based on GIMMS NDVI and climate data from 1982 to 2006, this study analyzed the impact of climate change on grassland in China. During the growing season, there were significant effects of precipitation on the growth of all the grassland types (P<0.05, except for meadow vegetation. For the air temperatures, there existed asymmetrical effects of maximum temperature (Tmax and minimum temperature (Tmin on grassland vegetation, especially for the temperate grasslands and alpine steppe. The growing season NDVI correlated negatively with Tmax but positively with Tmin for temperate grasslands. Seasonally, these opposite effects were only observed in summer. For alpine steppe, the growing season NDVI correlated positively with Tmax but negatively with Tmin, and this pattern of asymmetrical responses was only obvious in spring and autumn. Under the background of global asymmetric warming, more attention should be paid to this asymmetric response of grassland vegetation to daytime and night-time warming, especially when we want to predict the productivity of China’s grasslands in the future.

  3. Are Agrofuels a conservation threat or opportunity for grassland birds in the United States?

    Science.gov (United States)

    Robertson, Bruce A.; Rice, Robert A.; Ribic, Christine; Babcock, Bruce A.; Landis, Douglas A.; Herkert, James R.; Fletcher, Robert J.; Fontaine, Joseph J; Doran, Patrick J.; Schemske, Douglas W.

    2012-01-01

    In the United States, government-mandated growth in the production of crops dedicated to biofuel (agrofuels) is predicted to increase the demands on existing agricultural lands, potentially threatening the persistence of populations of grassland birds they support. We review recently published literature and datasets to (1) examine the ability of alternative agrofuel crops and their management regimes to provide habitat for grassland birds, (2) determine how crop placement in agricultural landscapes and agrofuel-related land-use change will affect grassland birds, and (3) identify critical research and policy-development needs associated with agrofuel production. We find that native perennial plants proposed as feedstock for agrofuel (switchgrass, Panicum virgatum, and mixed grass—forb prairie) have considerable potential to provide new habitat to a wide range of grassland birds, including rare and threatened species. However, industrialization of agrofuel production that maximizes biomass, homogenizes vegetation structure, and results in the cultivation of small fields within largely forested landscapes is likely to reduce species richness and/or abundance of grassland-dependent birds. Realizing the potential benefits of agrofuel production for grassland birds' conservation will require the development of new policies that encourage agricultural practices specifically targeting the needs of grassland specialists. The broad array of grower-incentive programs in existence may deliver new agrofuel policies effectively but will require coordination at a spatial scale broader than currently practiced, preferably within an adaptive-management framework.

  4. Prairie dog decline reduces the supply of ecosystem services and leads to desertification of semiarid grasslands.

    Directory of Open Access Journals (Sweden)

    Lourdes Martínez-Estévez

    Full Text Available Anthropogenic impacts on North American grasslands, a highly endangered ecosystem, have led to declines of prairie dogs, a keystone species, over 98% of their historical range. While impacts of this loss on maintenance of grassland biodiversity have been widely documented, much less is known about the consequences on the supply of ecosystem services. Here we assessed the effect of prairie dogs in the supply of five ecosystem services by comparing grasslands currently occupied by prairie dogs, grasslands devoid of prairie dogs, and areas that used to be occupied by prairie dogs that are currently dominated by mesquite scrub. Groundwater recharge, regulation of soil erosion, regulation of soil productive potential, soil carbon storage and forage availability were consistently quantitatively or qualitatively higher in prairie dog grasslands relative to grasslands or mesquite scrub. Our findings indicate a severe loss of ecosystem services associated to the absence of prairie dogs. These findings suggest that contrary to a much publicize perception, especially in the US, prairie dogs are fundamental in maintaining grasslands and their decline have strong negative impacts in human well - being through the loss of ecosystem services.

  5. [Community structure and diversity of soil arthropods in naturally restored sandy grasslands after grazing].

    Science.gov (United States)

    Liu, Ren-tao; Zhao, Ha-lin; Zhao, Xue-yong

    2010-11-01

    Taking the Naiman Desertification Research Station under Chinese Academy of Sciences as a base, an investigation was conducted on the community structure of soil arthropods in the naturally restored sandy grasslands after different intensity grazing disturbance, with the effects of vegetation and soil on this community structure approached. In the non-grazing grassland, soil arthropods were rich in species and more in individuals, and had the highest diversity. In the restored grassland after light grazing, soil arthropods had the lowest evenness and diversity. In the restored grassland after moderate grazing, the individuals of soil arthropods were lesser but the major groups were more, and the evenness and diversity were higher. In the restored grassland after heavy grazing, the individuals of soil arthropods were more but the major groups were lesser, and the diversity was higher. Plant individuals' number, vegetation height and coverage, and soil alkalinity were the main factors affecting the soil arthropod community in naturally restored grasslands after different intensity grazing disturbance. It was implied that after 12-year exclosure of grassland, soil arthropod community could be recovered to some degree, while grazing disturbance had long-term negative effects on the arthropod community.

  6. Grasslands and Croplands Have Different Microbial Biomass Carbon Levels per Unit of Soil Organic Carbon

    Directory of Open Access Journals (Sweden)

    Terence P. McGonigle

    2017-07-01

    Full Text Available Primarily using cropped systems, previous studies have reported a positive linear relationship between microbial biomass carbon (MBC and soil organic carbon (SOC. We conducted a meta-analysis to explore this relationship separately for grasslands and croplands using available literature. Studies were limited to those using fumigation–extraction for MBC for field samples. Trials were noted separately where records were distinct in space or time. Grasslands were naturally occurring, restored, or seeded. Cropping systems were typical of the temperate zone. MBC had a positive linear response to increasing SOC that was significant in both grasslands (p < 0.001; r2 = 0.76 and croplands (p < 0.001; r2 = 0.48. However, MBC increased 2.5-fold more steeply per unit of increasing SOC for grassland soils, as compared to the corresponding response in cropland soils. Expressing MBC as a proportion of SOC across the regression overall, slopes corresponded to 2.7% for grasslands and 1.1% for croplands. The slope of the linear relationship for grasslands was significantly (p = 0.0013 steeper than for croplands. The difference between the two systems is possibly caused by a greater proportion of SOC in grasslands being active rather than passive, relative to that in croplands, with that active fraction promoting the formation of MBC.

  7. Assessing the biophysical naturalness of grassland in eastern North Dakota with hyperspectral imagery

    Science.gov (United States)

    Zhou, Qiang

    Over the past two decades, non-native species within grassland communities have quickly developed due to human migration and commerce. Invasive species like Smooth Brome grass (Bromus inermis) and Kentucky Blue Grass (Poa pratensis), seriously threaten conservation of native grasslands. This study aims to discriminate between native grasslands and planted hayfields and conservation areas dominated by introduced grasses using hyperspectral imagery. Hyperspectral imageries from the Hyperion sensor on EO-1 were acquired in late spring and late summer on 2009 and 2010. Field spectra for widely distributed species as well as smooth brome grass and Kentucky blue grass were collected from the study sites throughout the growing season. Imagery was processed with an unmixing algorithm to estimate fractional cover of green and dry vegetation and bare soil. As the spectrum is significantly different through growing season, spectral libraries for the most common species are then built for both the early growing season and late growing season. After testing multiple methods, the Adaptive Coherence Estimator (ACE) was used for spectral matching analysis between the imagery and spectral libraries. Due in part to spectral similarity among key species, the results of spectral matching analysis were not definitive. Additional indexes, "Level of Dominance" and "Band variance", were calculated to measure the predominance of spectral signatures in any area. A Texture co-occurrence analysis was also performed on both "Level of Dominance" and "Band variance" indexes to extract spatial characteristics. The results suggest that compared with disturbed area, native prairie tend to have generally lower "Level of Dominance" and "Band variance" as well as lower spatial dissimilarity. A final decision tree model was created to predict presence of native or introduced grassland. The model was more effective for identification of Mixed Native Grassland than for grassland dominated by a single

  8. Lesser prairie-chicken avoidance of trees in a grassland landscape

    Science.gov (United States)

    Lautenbach, Joseph M.; Plumb, Reid T.; Robinson, Samantha G.; Hagen, Christian A.; Haukos, David A.; Pitman, James C.

    2016-01-01

    Grasslands are among the most imperiled ecosystems in North America. Reasons that grasslands are threatened include conversion to row-crop agriculture, fragmentation, and changes in fire regimes. The reduction of fire processes in remaining prairies has resulted in tree encroachment and establishment in grasslands, further reducing grassland quantity and quality. Grassland birds have been experiencing precipitous population declines in recent decades, commensurate with landscape changes to grasslands. The lesser prairie-chicken (Tympanuchus pallidicinctus Ridgway) is a declining species of prairie grouse of conservation concern. We used second- and third-order habitat selection metrics to test if female lesser prairie-chickens avoid grasslands where trees were present. Our results indicated that female lesser prairie-chickens selected habitats avoiding the nearest trees by 283 m on average, nearly twice as far as would be expected at random. Lesser prairie-chickens were 40 times more likely to use habitats with tree densities of 0 trees ∙ ha− 1 than habitats with 5 trees ∙ ha− 1. Probability of use indicated that lesser prairie-chickens were 19 times more likely to use habitats 1000 m from the nearest tree when compared with using habitats 0 m from the nearest tree. Nest survival was not affected at densities 2 trees ∙ ha− 1. Avoidance of trees could be due to perceived increased predation risk, reduced habitat quality, or a combination of these potentially confounding factors. Preventing further establishment and expansion of trees in landscapes occupied by lesser prairie-chickens could contribute to the continued persistence of the species. Additionally, restoring grasslands through tree removal may facilitate conservation efforts for grassland species such as the lesser prairie-chicken by improving habitat quality and promoting expansion of occupied range.

  9. Effects of 10-Year Management Regimes on the Soil Seed Bank in Saline-Alkaline Grassland

    Science.gov (United States)

    Ma, Hongyuan; Yang, Haoyu; Liang, Zhengwei; Ooi, Mark K. J.

    2015-01-01

    Background Management regimes for vegetation restoration of degraded grasslands can significantly affect the process of ecological succession. However, few studies have focused on variation in the soil seed bank during vegetation restoration under different management regimes, especially in saline-alkaline grassland habitats. Our aim was to provide insights into the ecological effects of grassland management regimes on soil seed bank composition and vegetation establishment in mown, fenced, transplanted and natural grassland sites, all dominated by the perennial rhizomatous grass Leymus chinensis. Methodology We studied species composition and diversity in both the soil seed bank and aboveground vegetation in differently managed grasslands in Northeast China. An NMDS (nonmetric multidimensional scaling) was used to evaluate the relationship between species composition, soil seed banks, aboveground vegetation and soil properties. Principal Findings Fenced and mown grassland sites had high density and species richness in both the soil seed bank and aboveground vegetation. The Transplanted treatment exhibited the highest vegetation growth and seed production of the target species L. chinensis. Seeds of L. chinensis in the soil occurred only in transplanted and natural grassland. Based on the NMDS analysis, the number of species in both the soil seed bank and aboveground vegetation were significantly related to soil Na+, Cl-, RSC (residual sodium carbonate), alkalinity, ESP (exchangeable sodium percentage) and AP (available phosphorus). Conclusions Soil seed bank composition and diversity in the saline-alkaline grassland were significantly affected by the management regimes implemented, and were also significantly related to the aboveground vegetation and several soil properties. Based on vegetative growth, reproductive output and maintenance of soil seed bank, the transplanting was identified as the most effective method for relatively rapid restoration of the target

  10. Traditional cattle grazing in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.

    Directory of Open Access Journals (Sweden)

    Péter Török

    Full Text Available Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i How does cattle grazing affect species composition and diversity of the grasslands? (ii What are the effects of grazing on short-lived and perennial noxious species? (iii Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands was sampled from 2006-2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable

  11. Recent trends, drivers, and projections of carbon cycle processes in forests and grasslands of North America

    Science.gov (United States)

    Domke, G. M.; Williams, C. A.; Birdsey, R.; Pendall, E.

    2017-12-01

    In North America forest and grassland ecosystems play a major role in the carbon cycle. Here we present the latest trends and projections of United States and North American carbon cycle processes, stocks, and flows in the context of interactions with global scale budgets and climate change impacts in managed and unmanaged grassland and forest ecosystems. We describe recent trends in natural and anthropogenic disturbances in these ecosystems as well as the carbon dynamics associated with land use and land cover change. We also highlight carbon management science and tools for informing decisions and opportunities for improving carbon measurements, observations, and projections in forests and grasslands.

  12. 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

  13. Effects of management practices on grassland birds: Grasshopper Sparrow

    Science.gov (United States)

    Dechant, Jill A.; Sondreal, Marriah L.; Johnson, Douglas H.; Igl, Lawrence D.; Goldade, Christopher M.; Nenneman, Melvin P.; Euliss, Betty R.

    1998-01-01

    Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 5,500 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which provides the fundamental components or keys to management for the species. A section on breeding range outlines the current breeding distribution of the species in North America, including areas that could not be mapped using BBS data. The suitable habitat section describes the breeding habitat and occasionally microhabitat characteristics of the species, especially those habitats that occur in the Great Plains. Details on habitat and microhabitat requirements often provide clues to how a species will respond to a particular management practice. A table near the end of the account complements the section on suitable habitat, and lists the specific habitat characteristics for the species by individual studies. A special section on prey habitat is included for those predatory species that have more specific prey requirements. The area requirements section provides details on territory and home range sizes, minimum area requirements, and the effects of patch size, edges, and other landscape and habitat features on abundance and productivity. It may be futile to manage a small block of suitable habitat for a species that has minimum area requirements that are larger than the area being managed. The Brown-headed Cowbird (Molothrus ater) is an obligate brood parasite of many grassland birds. The section on cowbird brood parasitism summarizes rates

  14. Monitoring soil greenhouse gas emissions from managed grasslands

    Science.gov (United States)

    Díaz-Pinés, Eugenio; Lu, Haiyan; Butterbach-Bahl, Klaus; Kiese, Ralf

    2014-05-01

    Grasslands in Central Europe are of enormous social, ecological and economical importance. They are intensively managed, but the influence of different common practices (i.e. fertilization, harvesting) on the total greenhouse gas budget of grasslands is not fully understood, yet. In addition, it is unknown how these ecosystems will react due to climate change. Increasing temperatures and changing precipitation will likely have an effect on productivity of grasslands and on bio-geo-chemical processes responsible for emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). In the frame of the TERENO Project (www.tereno.net), a long-term observatory has been implemented in the Ammer catchment, southern Germany. Acting as an in situ global change experiment, 36 big lysimeters (1 m2 section, 150 cm height) have been translocated along an altitudinal gradient, including three sites ranging from 600 to 860 meters above sea level. In addition, two treatments have been considered, corresponding to different management intensities. The overall aim of the pre-alpine TERENO observatory is improving our understanding of the consequences of climate change and management on productivity, greenhouse gas balance, soil nutritional status, nutrient leaching and hydrology of grasslands. Two of the sites are equipped with a fully automated measurement system in order to continuously and accurately monitor the soil-atmosphere greenhouse gas exchange. Thus, a stainless steel chamber (1 m2 section, 80 cm height) is controlled by a robotized system. The chamber is hanging on a metal structure which can move both vertically and horizontally, so that the chamber is able to be set onto each of the lysimeters placed on the field. Furthermore, the headspace of the chamber is connected with a gas tube to a Quantum Cascade Laser, which continuously measures CO2, CH4, N2O and H2O mixing ratios. The chamber acts as a static chamber and sets for 15 minutes onto each lysimeter

  15. Nocturnal activity of nesting shrubland and grassland passerines: Chapter 9

    Science.gov (United States)

    Slay, Christy M.; Ellison, Kevin S.; Ribic, Christine; Smith, Kimberly G.; Schmitz, Carolyn M.

    2013-01-01

    Nocturnal activity of nesting passerines is largely undocumented in field situations. We used video recordings to quantify sleep patterns of four shrubland and three grassland bird species during the nestling period. All species exhibited “back sleep” (bill tucked under scapular feathers); individuals woke frequently for vigils of their surroundings. Sleep-bout duration varied from 6 minutes (grasshopper sparrow) to 28 minutes (blue-winged warbler, field sparrow). Duration on nest varied from 6.4 hours (field sparrow) to 8.8 hours (indigo bunting). Adults woke 20–30 minutes before sunrise. First morning absence from the nest was short; nestlings were fed within 12 minutes of a parent’s departure. Further research is needed to understand energetic costs of sleep and behavioral adaptations to environmental pressures.

  16. Transient behavior of cadmium in a grassland arthropod food chain

    International Nuclear Information System (INIS)

    Van Hook, R.I.; Yates, A.J.

    1975-01-01

    Biological assimilation and transport of cadmium were determined for an arthropod food chain in an east Tennessee grassland community. Laboratory experiments demonstrated that there were no significant differences (P greater than 0.05) in assimilation rates (17 percent assimilation per day) or biological half-lives (7 days) of 109 Cd either as soluble nitrate or insoluble oxide in crickets under identical conditions. Field experiments demonstrated that primary consumers (crickets) accumulated 109 Cd much more rapidly (uptake rate = 0.55 day -1 ) than did the spider predators (uptake rate = 0.08 day -1 ). Equilibrium concentrations in crickets were obtained in 9 days (0.04 ppM cadmium), while equilibrium was not reached in spiders during the 30-day study. Food-chain concentration of cadmium did not occur as crickets accumulated levels of cadmium 60 percent of that in their vegetation food sources and spiders accumulated only 70 percent of the cadmium present in the cricket tissues

  17. Experimental control of Spanish broom (Spartium junceum invading natural grasslands

    Directory of Open Access Journals (Sweden)

    Cristina Sanhueza

    2012-12-01

    Full Text Available A group of legumes generically known as brooms are among the most successful shrubs invading grasslands in South America and otherregions. These species share a set of biological features that enhance their invasiveness, such as abundant and long-lasting seed banks,aggressive root systems and rapid growth, combined with their ability for re-sprouting after cutting or burning and for avoiding herbivores.They grow in dense stands that exclude native vegetation and are able to change ecological processes, increasing fire frequency and intensity,and fixing atmospheric nitrogen. The Spanish broom (Spartium junceum is a shrub native form the Mediterranean that was introduced intothe Argentine Pampas grasslands where it spreads over remnants of pristine ecosystems, threatening their biodiversity. This paper reports theresults obtained after an adaptive management strategy aimed at controlling this species in a nature reserve, and compares the efficiency ofdifferent mechanical and chemical control techniques in terms of the number of plants killed and the effects on surrounding vegetation andon the recruitment of broom seedlings. Control was implemented in two phases, the first included three treatments: i cut at the base of theplant, ii cut followed by the immediate application of Togar (Picloram 3% + Triclopyr 6%, at a 5% dilution in diesel oil on top of the cut stump, and iii foliar spraying with Togar. The follow-up treatments, implemented one year later, consisted of spraying the re-sprouts with Togar (5% in diesel oil or Glyphosate 36% (2% in water. The best option in terms of controlling Spanish broom was spraying the resprouts with Togar which gave 100% mortality of the treated plants, compared with values of 40% - 100% re-sprouting for the other optionstested. None of the methods was associated with an increase in seedling recruitment, nor with significant changes in the vegetation in the immediate vicinity of the controlled brooms.

  18. Surface temperature retrieval in a temperate grassland with multiresolution sensors

    Science.gov (United States)

    Goetz, S. J.; Halthore, R. N.; Hall, F. G.; Markham, B. L.

    1995-12-01

    Radiometric surface temperatures retrieved at various spatial resolutions from aircraft and satellite measurements at the FIFE site in eastern Kansas were compared with near-surface temperature measurements to determine the accuracy of the retrieval techniques and consistency between the various sensors. Atmospheric characterizations based on local radiosonde profiles of temperature, pressure, and water vapor were used with the LOWTRAN-7 and MODTRAN atmospheric radiance models to correct measured thermal radiances of water and grassland targets for atmospheric attenuation. Comparison of retrieved surface temperatures from a helicopter-mounted modular multispectral radiometer (MMR) (˜5-m "pixel"), C-130 mounted thematic mapper simulator (TMS) (NS001, ˜20-m pixel), and the Landsat 5 thematic mapper (TM) (120-m pixel) was done. Differences between atmospherically corrected radiative temperatures and near-surface measurements ranged from less than 1°C to more than 8°C. Corrected temperatures from helicopter-MMR and NS001-TMS were in general agreement with near-surface infrared radiative thermometer (IRT) measurements collected from automated meteorological stations, with mean differences of 3.2°C and 1.7°C for grassland targets. Much better agreement (within 1°C) was found between the retrieved aircraft surface temperatures and near-surface measurements acquired with a hand-held mast equipped with a MMR and IRT. The NS001-TMS was also in good agreement with near-surface temperatures acquired over water targets. In contrast, the Landsat 5 TM systematically overestimated surface temperature in all cases. This result has been noted previously but not consistently. On the basis of the results reported here, surface measurements were used to provide a calibration of the TM thermal channel. Further evaluation of the in-flight radiometric calibration of the TM thermal channel is recommended.

  19. Modelling nitrous oxide emissions from grazed grassland systems

    International Nuclear Information System (INIS)

    Wang Junye; Cardenas, Laura M.; Misselbrook, Tom H.; Cuttle, Steve; Thorman, Rachel E.; Li Changsheng

    2012-01-01

    Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification-DeComposition (DNDC), has been modified to describe N 2 O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N 2 O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N 2 O emissions increased as the grazing intensity increased. - Highlights: ► Parameterisation of grazing system using grazing intensity. ► Modification of UK D NDC for the UK soil and weather conditions. ► Validation of the UK D NDC against measured data of N 2 O emissions in three UK sites. ► Estimating influence of animal grazing practises on N 2 O emissions. - Grazing system was parameterised using grazing intensity and UK-DNDC model was modified and validated against measured data of N 2 O emissions in three UK sites.

  20. Grassland communities of traditional orchards in the Western Carpathians (Slovakia

    Directory of Open Access Journals (Sweden)

    Hubert Zarnovican

    2017-06-01

    Full Text Available Traditional orchards are a valuable feature of the rural landscape and they are specific for regions with scattered settlement such as the Myjava hilly land and White Carpathians. Here, the permanent species-rich grasslands beneath trees were regularly managed in the traditional manner until some were replaced in the 1970’s and 80’s by intensively managed orchards, some of which were abandoned in the early 1990’s. Our 2011–2015 phytosociological research followed the standard Braun-Blanquet approach. We classified 178 phytosociological relevés recorded in orchard meadows (156 relevés, former intensively managed orchards (16 relevés, and two relevés from a semi-intensively grazed orchard. Traditionally managed orchard meadows were classified in the following five units: (i Pastinaco sativae-Arrhenatheretum elatioris – thermophilous variant, (ii Pastinaco sativae-Arrhenatheretum elatioris – transitional variant to Alchemillo-Arrhenatheretum elatioris, (iii Ranunculo bulbosi-Arrhenatheretum elatioris, (iv Onobrychido viciifoliae-Brometum erecti, and (v Brachypodio pinnati-Molinietum arundinaceae. Formerly intensively managed large-scale orchards were classified as Pastinaco sativae-Arrhenatheretum elatioris association and the semi-intensively grazed orchard as Lolio perennis-Cynosuretum cristati association. The species composition varies considerably due to tree-shading and different management treatments applied in the orchards, so the relevés of the delimited syntaxonomic units are not typical and have transitional character. Moisture, soil nutrients, and soil reaction were identified as the main environmental gradients influencing species composition. We tested four management treatments in direct gradient analysis and found that abandonment has the strongest effect on species composition. Comparison of grassland vegetation in the studied traditional orchards with that described in Germany reveals differences in species

  1. Grassland invader responses to realistic changes in native species richness.

    Science.gov (United States)

    Rinella, Matthew J; Pokorny, Monica L; Rekaya, Romdhane

    2007-09-01

    The importance of species richness for repelling exotic plant invasions varies from ecosystem to ecosystem. Thus, in order to prioritize conservation objectives, it is critical to identify those ecosystems where decreasing richness will most greatly magnify invasion risks. Our goal was to determine if invasion risks greatly increase in response to common reductions in grassland species richness. We imposed treatments that mimic management-induced reductions in grassland species richness (i.e., removal of shallow- and/or deep-rooted forbs and/or grasses and/or cryptogam layers). Then we introduced and monitored the performance of a notorious invasive species (i.e., Centaurea maculosa). We found that, on a per-gram-of-biomass basis, each resident plant group similarly suppressed invader growth. Hence, with respect to preventing C. maculosa invasions, maintaining overall productivity is probably more important than maintaining the productivity of particular plant groups or species. But at the sites we studied, all plant groups may be needed to maintain overall productivity because removing forbs decreased overall productivity in two of three years. Alternatively, removing forbs increased productivity in another year, and this led us to posit that removing forbs may inflate the temporal productivity variance as opposed to greatly affecting time-averaged productivity. In either case, overall productivity responses to single plant group removals were inconsistent and fairly modest, and only when all plant groups were removed did C. maculosa growth increase substantially over a no-removal treatment. As such, it seems that intense disturbances (e.g., prolonged drought, overgrazing) that deplete multiple plant groups may often be a prerequisite for C. maculosa invasion.

  2. Prescribed burning supports grassland biodiversity - A multi-species study

    Science.gov (United States)

    Valkó, Orsolya; Deák, Balázs; Magura, Tibor; Török, Péter; Kelemen, András; Tóth, Katalin; Horváth, Roland; Nagy, Dávid; Debnár, Zsuzsanna; Zsigrai, György; Kapocsi, István; Tóthmérész, Béla

    2017-04-01

    During ancient times, fire was an important factor shaping European landscapes. Nowadays, prescribed burning can be one of the most effective conservation tools for the management of open landscapes, controlling dominant species, reducing accumulated litter or decreasing wildfire risk. In a prescribed burning experiment, we studied the effects of fire on dry alkaline grasslands. We tested whether autumn prescribed burning can be an alternative conservation measure in these grasslands. We selected six sites in Hungary: in three sites, prescribed burning was applied in November 2011, while three sites remained unburnt. We studied the effects of fire on soil characteristics, plant biomass and on the vegetation and arthropod assemblages (isopods, spiders, ground beetles and rove beetles). Soluble salt content increased significantly in the burnt sites, but soil pH, organic matter, potassium and phosphorous did not change. We found that prescribed fire had several positive effects from the nature conservation viewpoint. Diversity and the number of flowering shoots were higher, and the cover of the dominant grass was lower in the burnt sites. Graminoid biomass was lower, while total, green and forb biomass were higher in the burnt plots compared to the control ones. Our findings suggest that prescribed burning fire did not harm arthropods; species-level analyses showed that out of the most abundant invertebrate species, the abundance of ten was not affected, one decreased and one increased after burning. Our findings highlight that mosaic prescribed fire is a viable management tool in open landscapes, because it supports plant diversity and does not threaten arthropods.

  3. Sensibility and time heterogeneity of Biome-BGC model parameters%Biome-BGC模型参数的敏感性和时间异质性

    Institute of Scientific and Technical Information of China (English)

    刘秋雨; 张廷龙; 孙睿; 王博闻; 叶欣欣; 李一哲

    2017-01-01

    生态过程模型为研究陆表生态系统水、碳、氮等物质的循环提供了一种有效的手段.模型与数据同化结合可建立模拟与观测之间的桥梁,同时提高模型与观测两种方法揭示地表真实状况的有效性.但模型参数的特性,将直接影响到模型模拟及数据同化的精度.传统观念认为,生态过程模型参数在相同植被类型条件下是固定不变的,但近期研究已开始关注其时空异质性.本文以Biome-BGC模型为例,利用美国哈佛森林Environmental Monitoring Site (EMS)通量观测站的相关数据,对哈佛森林地区水、碳通量进行模拟.首先对模型参数进行敏感性分析;然后应用模拟退火算法,构造目标函数,使待优化的敏感参数在合理阈值范围内不断变动反复迭代,获取逐月的最优参数值;通过引入变异系数,对敏感参数的时间异质性进行分析.结果表明:生态过程模型参数最优值并非常量,而会随时间表现出异质性,而且各参数时间异质性大小差异显著.文中对Biome-BGC模型的敏感参数按时间异质性大小划分了相应的等级.研究结果有助于加深对生态过程模型参数特性的认识,为参数的合理取值及动态优化提供思路与依据,有助于进一步提高模型模拟和数据同化的精度与效率.%Ecological process model provides an effective way for studying water,carbon and nitrogen cycles of terrestrial ecosystem.The combination of the model and data assimilation could build a link between observation and simulation,which improves the effectiveness of model and observation methods to reveal the real state of land surface,but the accuracy of simulation and assimilation is directly affected by model parameters.Parameters are constants in traditional opinion;however,some current studies have focused on the time-space heterogeneity of parameters.In this paper,we used Harvard Forest Environmental Monitoring Site (EMS) data to simulate

  4. The pollination ecology of an assemblage of grassland asclepiads in South Africa.

    Science.gov (United States)

    Ollerton, Jeff; Johnson, Steven D; Cranmer, Louise; Kellie, Sam

    2003-12-01

    The KwaZulu-Natal region of South Africa hosts a large diversity of asclepiads (Apocynaceae: Asclepiadoideae), many of which are endemic to the area. The asclepiads are of particular interest because of their characteristically highly evolved floral morphology. During 3 months of fieldwork (November 2000 to January 2001) the flower visitors and pollinators to an assemblage of nine asclepiads at an upland grassland site were studied. These observations were augmented by laboratory studies of flower morphology (including scanning electron microscopy) and flower colour (using a spectrometer). Two of the specialized pollination systems that were documented are new to the asclepiads: fruit chafer pollination and pompilid wasp pollination. The latter is almost unique in the angiosperms. Taxa possessing these specific pollination systems cluster together in multidimensional phenotype space, suggesting that there has been convergent evolution in response to similar selection to attract identical pollinators. Pollination niche breadth varied from the very specialized species, with only one pollinator, to the more generalized, with up to ten pollinators. Pollinator sharing by the specialized taxa does not appear to have resulted in niche differentiation in terms of the temporal or spatial dimensions, or with regards to placement of pollinaria. Nestedness analysis of the data set showed that there was predictability and structure to the pattern of plant-pollinator interactions, with generalist insects visiting specialized plants and vice versa. The research has shown that there is still much to be learned about plant-pollinator interactions in areas of high plant diversity such as South Africa.

  5. Future projections of fire danger in Brazilian biomes in the 21st century

    Science.gov (United States)

    Libonati, Renata; Silva, Patrícia; DaCamara, Carlos; Bastos, Ana

    2016-04-01

    In the global context, Brazil is one of the regions more severely affected by fire occurrences, with important consequences in the global CO2 balance, the state of the Amazon forest and the ecological diversity of the region. Brazil is also one of the few regions experiencing a raise in annual mean temperature above 2.5o during the 20th century, which may further increase between 2o and 7o until 2100 and, likely, be accompanied by a decrease in precipitation [1]. As the fire occurrence and severity largely depends on these two variables, it is worth assessing the evolution of fire danger for the coming decades. In order to obtain a detailed characterization of the future fire patterns in the different biomes of Brazil, we use outputs from a regional-downscaling of the EC-Earth climate model at 0.44 degrees spatial resolution for two future scenarios, an intermediate (RCP4.5) and a more severe (RCP8.5) one. We use a fire danger index specifically developed for the Brazilian climate and biome characteristics, the IFR from INPE. This index relies on values of maximum temperature, accumulated precipitation over different periods, minimum relative humidity and vegetation cover to estimate the likelihood of fire occurrence. We find a systematic increase of the days with critical fire risk, which is more pronounced in RCP8.5 and mostly affects months when fire activity takes place. Temperature increase is the most determinant factor for the increase in fire danger in the dry regions of savannah and shrubland, a result to be expected as fuel is already very dry. [1] Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on

  6. Evaporation from Pinus caribaea plantations on former grassland soils under maritime tropical conditions.

    NARCIS (Netherlands)

    Waterloo, M.J.; Bruijnzeel, L.A.; Vugts, H.F.; Rawaqa, T.T.

    1999-01-01

    Wet canopy and dry canopy evaporation from young and mature plantations of Pinus caribaea on former grassland soils under maritime tropical conditions in southwestern Viti Levu, Fiji, were determined using micrometeorological and hydrological techniques. Modeled annual evaporation totals (ET) of

  7. Evaporation from Pinus caribaea plantations on former grassland soils under maritime tropical conditions

    NARCIS (Netherlands)

    Waterloo, M.J.; Bruijnzeel, L.A.; Vugts, H.F.; Rawaqa, T.T.

    1999-01-01

    Wet canopy and dry canopy evaporation from young and mature plantations of Pinus caribaea on former grassland soils under maritime tropical conditions in southwestern Viti Levu, Fiji, were determined using micrometeorological and hydrological techniques. Modeled annual evaporation totals (ET) of

  8. NPP Grassland: Beacon Hill, U.K., 1972-1993, R1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains two ASCII text files, one providing productivity measurements for a chalk grassland on Beacon Hill, West Sussex, U.K. (50.92 N, -0.85 W) and...

  9. Soil communities promote temporal stability and species asynchrony in experimental grassland communities

    NARCIS (Netherlands)

    Pellkofer, Sarah; Van Der Heijden, Marcel G A; Schmid, Bernhard; Wagg, Cameron

    2016-01-01

    Background Over the past two decades many studies have demonstrated that plant species diversity promotes primary productivity and stability in grassland ecosystems. Additionally, soil community characteristics have also been shown to influence the productivity and composition of plant communities,

  10. Seasonal dynamics and vertical distribution of plant-feeding nematode communities in grasslands

    NARCIS (Netherlands)

    Verschoor, B.C.; Goede, de R.G.M.; Hoop, de J.W.; Vries, de F.W.

    2001-01-01

    The vertical distribution and seasonal dynamics of plant- and fungal-feeding nematode taxa in permanent grasslands were investigated. Dolichodoridae, Paratylenchus, Pratylenchus, Tylenchidae and Aphelenchoides dominated the upper 10 cm soil and their numbers strongly decreased with depth. The

  11. Threshold responses to interacting global changes in a California grassland ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Field, Christopher [Carnegie Inst. of Science, Stanford, CA (United States); Mooney, Harold [Stanford Univ., CA (United States); Vitousek, Peter [Stanford Univ., CA (United States)

    2015-02-02

    Building on the history and infrastructure of the Jasper Ridge Global Change Experiment, we conducted experiments to explore the potential for single and combined global changes to stimulate fundamental type changes in ecosystems that start the experiment as California annual grassland. Using a carefully orchestrated set of seedling introductions, followed by careful study and later removal, the grassland was poised to enable two major kinds of transitions that occur in real life and that have major implications for ecosystem structure, function, and services. These are transitions from grassland to shrubland/forest and grassland to thistle patch. The experiment took place in the context of 4 global change factors – warming, elevated CO2, N deposition, and increased precipitation – in a full-factorial array, present as all possible 1, 2, 3, and 4-factor combinations, with each combination replicated 8 times.

  12. Monitoring Grassland Tourist Season of Inner Mongolia, China Using Remote Sensing Data

    Directory of Open Access Journals (Sweden)

    Quansheng Ge

    2014-01-01

    Full Text Available Phenology-driven events, such as spring wildflower displays or fall tree colour, are generally appreciated by tourists for centuries around the world. Monitoring when tourist seasons occur using satellite data has been an area of growing research interest in recent decades. In this paper, a valid methodology for detecting the grassland tourist season using remote sensing data was presented. On average, the beginning, the best, and the end of grassland tourist season of Inner Mongolia, China, occur in late June (±30 days, early July (±30 days, and late July (±50 days, respectively. In south region, the grassland tourist season appeared relatively late. The length of the grassland tourist season is about 90 days with strong spatial trend. South areas exhibit longer tourist season.

  13. Plant species occurrence patterns in Eurasian grasslands reflect adaptation to nutrient ratios

    NARCIS (Netherlands)

    Roeling, Ineke S.; Ozinga, Wim A.; van Dijk, Jerry; Eppinga, Maarten B.; Wassen, Martin J.

    2018-01-01

    Previous studies of Eurasian grasslands have suggested that nutrient ratios, rather than absolute nutrient availabilities and associated productivity, may be driving plant species richness patterns. However, the underlying assumption that species occupy distinct niches along nutrient ratio gradients

  14. Spontaneous colonization of restored dry grasslands by target species: restoration proceeds beyond sowing regional seed mixtures

    Czech Academy of Sciences Publication Activity Database

    Johanidesová, E.; Fajmon, K.; Jongepierová, I.; Prach, Karel

    2015-01-01

    Roč. 70, č. 4 (2015), s. 631-638 ISSN 0142-5242 Institutional support: RVO:67985939 Keywords : restoration * grasslands * spontaneous colonization Subject RIV: EH - Ecology, Behaviour Impact factor: 1.617, year: 2015

  15. PCDD/F and Aromatic Emissions from Simulated Forest and Grassland Fires

    Science.gov (United States)

    Emissions of polychlorinated dibenzodioxin and polychlorinated dibenzofuran (PCDD/F) from simulated grassland and forest fires were quantitatively sampled to derive emission factors in support of PCDD/F inventory development. Grasses from Kentucky and Minnesota; forest shrubs fro...

  16. Strategic Grassland Bird Conservation throughout the annual cycle: Linking policy alternatives, landowner decisions, and biological population outcomes

    Science.gov (United States)

    Drum, Ryan G.; Ribic, Christine; Koch, Katie; Lonsdorf, Eric V.; Grant, Edward C.; Ahlering, Marissa; Barnhill, Laurel; Dailey, Thomas; Lor, Socheata; Mueller, Connie; Pavlacky, D.C.; Rideout, Catherine; Sample, David W.

    2015-01-01

    Grassland bird habitat has declined substantially in the United States. Remaining grasslands are increasingly fragmented, mostly privately owned, and vary greatly in terms of habitat quality and protection status. A coordinated strategic response for grassland bird conservation is difficult, largely due to the scope and complexity of the problem, further compounded by biological, sociological, and economic uncertainties. We describe the results from a collaborative Structured Decision Making (SDM) workshop focused on linking social and economic drivers of landscape change to grassland bird population outcomes. We identified and evaluated alternative strategies for grassland bird conservation using a series of rapid prototype models. We modeled change in grassland and agriculture cover in hypothetical landscapes resulting from different landowner decisions in response to alternative socio-economic conservation policy decisions. Resulting changes in land cover at all three stages of the annual cycle (breeding, wintering, and migration) were used to estimate changes in grassland bird populations. Our results suggest that successful grassland bird conservation may depend upon linkages with ecosystem services on working agricultural lands and grassland-based marketing campaigns to engage the public. With further development, spatial models that link landowner decisions with biological outcomes can be essential tools for making conservation policy decisions. A coordinated non-traditional partnership will likely be necessary to clearly understand and systematically respond to the many conservation challenges facing grassland birds.

  17. Strategic Grassland Bird Conservation throughout the Annual Cycle: Linking Policy Alternatives, Landowner Decisions, and Biological Population Outcomes.

    Directory of Open Access Journals (Sweden)

    Ryan G Drum

    Full Text Available Grassland bird habitat has declined substantially in the United States. Remaining grasslands are increasingly fragmented, mostly privately owned, and vary greatly in terms of habitat quality and protection status. A coordinated strategic response for grassland bird conservation is difficult, largely due to the scope and complexity of the problem, further compounded by biological, sociological, and economic uncertainties. We describe the results from a collaborative Structured Decision Making (SDM workshop focused on linking social and economic drivers of landscape change to grassland bird population outcomes. We identified and evaluated alternative strategies for grassland bird conservation using a series of rapid prototype models. We modeled change in grassland and agriculture cover in hypothetical landscapes resulting from different landowner decisions in response to alternative socio-economic conservation policy decisions. Resulting changes in land cover at all three stages of the annual cycle (breeding, wintering, and migration were used to estimate changes in grassland bird populations. Our results suggest that successful grassland bird conservation may depend upon linkages with ecosystem services on working agricultural lands and grassland-based marketing campaigns to engage the public. With further development, spatial models that link landowner decisions with biological outcomes can be essential tools for making conservation policy decisions. A coordinated non-traditional partnership will likely be necessary to clearly understand and systematically respond to the many conservation challenges facing grassland birds.

  18. Plant litter dynamics in the forest-stream interface: precipitation is a major control across tropical biomes

    OpenAIRE

    Tonin, Alan M.; Gon?alves, Jos? F.; Bambi, Paulino; Couceiro, Sheyla R. M.; Feitoza, Lorrane A. M.; Fontana, Lucas E.; Hamada, Neusa; Hepp, Luiz U.; Lezan-Kowalczuk, V?nia G.; Leite, Gustavo F. M.; Lemes-Silva, Aurea L.; Lisboa, Leonardo K.; Loureiro, Rafael C.; Martins, Renato T.; Medeiros, Adriana O.

    2017-01-01

    Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even?though the tropics occupy 40% of the Earth?s land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Ama...

  19. [Parameter sensitivity of simulating net primary productivity of Larix olgensis forest based on BIOME-BGC model].

    Science.gov (United States)

    He, Li-hong; Wang, Hai-yan; Lei, Xiang-dong

    2016-02-01

    Model based on vegetation ecophysiological process contains many parameters, and reasonable parameter values will greatly improve simulation ability. Sensitivity analysis, as an important method to screen out the sensitive parameters, can comprehensively analyze how model parameters affect the simulation results. In this paper, we conducted parameter sensitivity analysis of BIOME-BGC model with a case study of simulating net primary productivity (NPP) of Larix olgensis forest in Wangqing, Jilin Province. First, with the contrastive analysis between field measurement data and the simulation results, we tested the BIOME-BGC model' s capability of simulating the NPP of L. olgensis forest. Then, Morris and EFAST sensitivity methods were used to screen the sensitive parameters that had strong influence on NPP. On this basis, we also quantitatively estimated the sensitivity of the screened parameters, and calculated the global, the first-order and the second-order sensitivity indices. The results showed that the BIOME-BGC model could well simulate the NPP of L. olgensis forest in the sample plot. The Morris sensitivity method provided a reliable parameter sensitivity analysis result under the condition of a relatively small sample size. The EFAST sensitivity method could quantitatively measure the impact of simulation result of a single parameter as well as the interaction between the parameters in BIOME-BGC model. The influential sensitive parameters for L. olgensis forest NPP were new stem carbon to new leaf carbon allocation and leaf carbon to nitrogen ratio, the effect of their interaction was significantly greater than the other parameter' teraction effect.

  20. Comment on Chiesi et al. (2011): “Use of BIOME-BGC to simulate Mediterranean forest carbon stocks”

    OpenAIRE

    Eastaugh CS

    2011-01-01

    The mechanistic forest growth model BIOME-BGC utilizes a “spin-up” procedure to estimate site parameters for forests in a steady-state condition, as they may have been expected to be prior to anthropogenic influence. Forests in this condition have no net growth, as living biomass accumulation is balanced by mortality. To simulate current ecosystems it is necessary to reset the model to reflect a forest of the correct development stage. The alternative approach of simply post-adjus...

  1. Soil Loss Vulnerability in an Agricultural Catchment in the Atlantic Forest Biome in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Rafael Gotardo

    2016-11-01

    Full Text Available This study estimates soil loss vulnerability using field samples and spatial data in a 30 km² area in the Atlantic forest biome in southern Brazil. The anthropogenic part of the landscape consists mainly of small agricultural properties. Soil loss vulnerability was calculated using adaptations of the universal soil loss equation. The results were compared to sediment data collected during field surveys. Spatial analysis was performed using a geographical information system (GIS and fine resolution data (1 m. Both field and spatial analyses produced similar results, 5.390 tons of soil loss per year using field data and 5.691 tons per year using GIS. Using soil loss and sediment data related to the Concordia River, we estimate that of all the exported sediment 25% of the lost soil reaches the river. These data are an effective source of information for municipal administrators of the region, which consists of small agricultural catchments (dominated by small properties that comprise the regional economy. A thematic map was used to determine sub-drainage priority as information for public managers.

  2. A mesic maximum in biological water use demarcates biome sensitivity to aridity shifts.

    Science.gov (United States)

    Good, Stephen P; Moore, Georgianne W; Miralles, Diego G

    2017-12-01

    Biome function is largely governed by how efficiently available resources can be used and yet for water, the ratio of direct biological resource use (transpiration, E T ) to total supply (annual precipitation, P) at ecosystem scales remains poorly characterized. Here, we synthesize field, remote sensing and ecohydrological modelling estimates to show that the biological water use fraction (E T /P) reaches a maximum under mesic conditions; that is, when evaporative demand (potential evapotranspiration, E P ) slightly exceeds supplied precipitation. We estimate that this mesic maximum in E T /P occurs at an aridity index (defined as E P /P) between 1.3 and 1.9. The observed global average aridity of 1.8 falls within this range, suggesting that the biosphere is, on average, configured to transpire the largest possible fraction of global precipitation for the current climate. A unimodal E T /P distribution indicates that both dry regions subjected to increasing aridity and humid regions subjected to decreasing aridity will suffer declines in the fraction of precipitation that plants transpire for growth and metabolism. Given the uncertainties in the prediction of future biogeography, this framework provides a clear and concise determination of ecosystems' sensitivity to climatic shifts, as well as expected patterns in the amount of precipitation that ecosystems can effectively use.

  3. Eastern deciduous forest biome progress report, September 1, 1975--August 31, 1976

    International Nuclear Information System (INIS)

    Burgess, R.L.; Tarr, N.E.

    1978-09-01

    The report concentrates on the six projects as well as results from synthesis activities at the Lake George, Lake Wingra, and Oak Ridge sites. The centralized analysis and modeling component and the Eastern Decidious Forest Biome Information Center progress during the past year are also addressed. The project on belowground dynamics of ecosystems is investigating the allocation of phytosynthetic products into fixed or labile storage pools. Root sampling, radioactive tracer techniques, and biochemical analyses are leading to an understanding of complete tree physioogy requisite for interpreting forest growth in different environments. The Role of Consumers project has begun to document the regulatory role of heterotrophs in an array of ecosystem niches. Decomposition of woody substrates, studies of the contribution of canopy and litter arthropods to material processing, and the flow and remineralization of phosphorus in lake systems are leading to a comprehensive understanding of the role of consumer organisms in ecosystem function. The Microdynamics of Detritus project continues its investigations of carbon and nitrogen dynamics in freshwater lakes. Examination of potential pathways of detritus processing is illustrating the parts that physical and biological processes play in the breakdown of organic materials

  4. Plants of the fynbos biome harbour host species-specific bacterial communities.

    Science.gov (United States)

    Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

    2016-08-01

    The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Soil-borne bacterial structure and diversity does not reflect community activity in Pampa biome.

    Science.gov (United States)

    Lupatini, Manoeli; Suleiman, Afnan Khalil Ahmad; Jacques, Rodrigo Josemar Seminoti; Antoniolli, Zaida Inês; Kuramae, Eiko Eurya; de Oliveira Camargo, Flávio Anastácio; Roesch, Luiz Fernando Würdig

    2013-01-01

    The Pampa biome is considered one of the main hotspots of the world's biodiversity and it is estimated that half of its original vegetation was removed and converted to agricultural land and tree plantations. Although an increasing amount of knowledge is being assembled regarding the response of soil bacterial communities to land use change, to the associated plant community and to soil properties, our understanding about how these interactions affect the microbial community from the Brazilian Pampa is still poor and incomplete. In this study, we hypothesized that the same soil type from the same geographic region but under distinct land use present dissimilar soil bacterial communities. To test this hypothesis, we assessed the soil bacterial communities from four land-uses within the same soil type by 454-pyrosequencing of 16S rRNA gene and by soil microbial activity analyzes. We found that the same soil type under different land uses harbor similar (but not equal) bacterial communities and the differences were controlled by many microbial taxa. No differences regarding diversity and richness between natural areas and areas under anthropogenic disturbance were detected. However, the measures of microbial activity did not converge with the 16S rRNA data supporting the idea that the coupling between functioning and composition of bacterial communities is not necessarily correlated.

  6. Local climatic conditions constrain soil yeast diversity patterns in Mediterranean forests, woodlands and scrub biome.

    Science.gov (United States)

    Yurkov, Andrey M; Röhl, Oliver; Pontes, Ana; Carvalho, Cláudia; Maldonado, Cristina; Sampaio, José Paulo

    2016-02-01

    Soil yeasts represent a poorly known fraction of the soil microbiome due to limited ecological surveys. Here, we provide the first comprehensive inventory of cultivable soil yeasts in a Mediterranean ecosystem, which is the leading biodiversity hotspot for vascular plants and vertebrates in Europe. We isolated and identified soil yeasts from forested sites of Serra da Arrábida Natural Park (Portugal), representing the Mediterranean forests, woodlands and scrub biome. Both cultivation experiments and the subsequent species richness estimations suggest the highest species richness values reported to date, resulting in a total of 57 and 80 yeast taxa, respectively. These values far exceed those reported for other forest soils in Europe. Furthermore, we assessed the response of yeast diversity to microclimatic environmental factors in biotopes composed of the same plant species but showing a gradual change from humid broadleaf forests to dry maquis. We observed that forest properties constrained by precipitation level had strong impact on yeast diversity and on community structure and lower precipitation resulted in an increased number of rare species and decreased evenness values. In conclusion, the structure of soil yeast communities mirrors the environmental factors that affect aboveground phytocenoses, aboveground biomass and plant projective cover. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. A multi-biome gap in understanding of crop and ecosystem responses to elevated CO2.

    Science.gov (United States)

    Leakey, Andrew D B; Bishop, Kristen A; Ainsworth, Elizabeth A

    2012-06-01

    A key finding from elevated [CO(2)] field experiments is that the impact of elevated [CO(2)] on plant and ecosystem function is highly dependent upon other environmental conditions, namely temperature and the availability of nutrients and soil moisture. In addition, there is significant variation in the response to elevated [CO(2)] among plant functional types, species and crop varieties. However, experimental data on plant and ecosystem responses to elevated [CO(2)] are strongly biased to economically and ecologically important systems in the temperate zone. There is a multi-biome gap in experimental data that is most severe in the tropics and subtropics, but also includes high latitudes. Physiological understanding of the environmental conditions and species found at high and low latitudes suggest they may respond differently to elevated [CO(2)] than well-studied temperate systems. Addressing this knowledge gap should be a high priority as it is vital to understanding 21st century food supply and ecosystem feedbacks on climate change. Published by Elsevier Ltd.

  8. SOIL ORGANIC MATTER FRACTIONS IN PRESERVED AND DISTURBED WETLANDS OF THE CERRADO BIOME

    Directory of Open Access Journals (Sweden)

    Ricardo Fernandes de Sousa

    2015-02-01

    Full Text Available Veredas are humid tropical ecosystems, generally associated to hydromorphic soils and a shallow water table. The soils of these ecosystems are affected by the use of the areas around these veredas. The objective of this study was to determine soil organic matter (SOM fractions in veredas adjacent to preserved (native savanna and disturbed environments (agricultural areas and pastures in the Cerrado biome. Soil samples were collected from the 0-10 and 10-20 cm layers along reference lines drawn along the relief following the upper, middle and lower positions of one of the slopes, in the direction of the draining line of the vereda. The soil analysis determined: total soil OC, total nitrogen and C:N ratio; C and N contents and C:N ratio in particulate and mineral-associated fractions (of SOM; fulvic acids, humic acids and humin fractions and ratio between humic and fulvic acids. The agricultural use around the veredas induced changes in the SOM fractions, more pronounced in the lower part of the slope. In the soil surface of this part, the OC levels in the humic substances and the particulate fraction of SOM, as well as total soil OC were reduced in the vereda next to crop fields.

  9. Introducing BASE: the Biomes of Australian Soil Environments soil microbial diversity database.

    Science.gov (United States)

    Bissett, Andrew; Fitzgerald, Anna; Meintjes, Thys; Mele, Pauline M; Reith, Frank; Dennis, Paul G; Breed, Martin F; Brown, Belinda; Brown, Mark V; Brugger, Joel; Byrne, Margaret; Caddy-Retalic, Stefan; Carmody, Bernie; Coates, David J; Correa, Carolina; Ferrari, Belinda C; Gupta, Vadakattu V S R; Hamonts, Kelly; Haslem, Asha; Hugenholtz, Philip; Karan, Mirko; Koval, Jason; Lowe, Andrew J; Macdonald, Stuart; McGrath, Leanne; Martin, David; Morgan, Matt; North, Kristin I; Paungfoo-Lonhienne, Chanyarat; Pendall, Elise; Phillips, Lori; Pirzl, Rebecca; Powell, Jeff R; Ragan, Mark A; Schmidt, Susanne; Seymour, Nicole; Snape, Ian; Stephen, John R; Stevens, Matthew; Tinning, Matt; Williams, Kristen; Yeoh, Yun Kit; Zammit, Carla M; Young, Andrew

    2016-01-01

    Microbial inhabitants of soils are important to ecosystem and planetary functions, yet there are large gaps in our knowledge of their diversity and ecology. The 'Biomes of Australian Soil Environments' (BASE) project has generated a database of microbial diversity with associated metadata across extensive environmental gradients at continental scale. As the characterisation of microbes rapidly expands, the BASE database provides an evolving platform for interrogating and integrating microbial diversity and function. BASE currently provides amplicon sequences and associated contextual data for over 900 sites encompassing all Australian states and territories, a wide variety of bioregions, vegetation and land-use types. Amplicons target bacteria, archaea and general and fungal-specific eukaryotes. The growing database will soon include metagenomics data. Data are provided in both raw sequence (FASTQ) and analysed OTU table formats and are accessed via the project's data portal, which provides a user-friendly search tool to quickly identify samples of interest. Processed data can be visually interrogated and intersected with other Australian diversity and environmental data using tools developed by the 'Atlas of Living Australia'. Developed within an open data framework, the BASE project is the first Australian soil microbial diversity database. The database will grow and link to other global efforts to explore microbial, plant, animal, and marine biodiversity. Its design and open access nature ensures that BASE will evolve as a valuable tool for documenting an often overlooked component of biodiversity and the many microbe-driven processes that are essential to sustain soil function and ecosystem services.

  10. PERMANENCE OF WATER EFFECTIVENESS IN THE ROOT ZONE OF THE CAATINGA BIOME

    Directory of Open Access Journals (Sweden)

    CARLOS ALEXANDRE GOMES COSTA

    2016-01-01

    Full Text Available Soil is an important water compartment into a watershed scale, mainly due to its role in providing water to plants and to the influence of antecedent moisture on the runoff initiation. The aim of this research is to assess the permanence of water effectiveness in the soil under preserved-vegetation constraints in the Caatinga biome, in the semiarid northeastern Brazil. For this purpose, hourly soil moisture measurements were collected with TDR and analyzed between 2003 and 2010 for three soil-vegetation associations in the Aiuaba Experimental Basin. The results showed that in nine months per year soil moisture was below wilting point for two associations, whose soils are Chromic Luvisol and Haplic Lixisol (Abruptic. In the third association, where the shallow soil Lithic Leptosol prevails, water was found non-effective four months per year. A possible reason for the high water permanence in the shallowest soil is the percolation process, generating sub-surface flow, which barely occurs in the deeper soils. In situ observations indicates that the long period of soil moisture below the wilting point was not enough to avoid the blooming season of the Caatinga vegetation during the rainy periods. Indeed, after the beginning of each rainy season, there is a growth of dense green vegetation, regardless of the long period under water shortage.

  11. Diversity of herbaceous plants and bacterial communities regulates soil resistome across forest biomes.

    Science.gov (United States)

    Hu, Hang-Wei; Wang, Jun-Tao; Singh, Brajesh K; Liu, Yu-Rong; Chen, Yong-Liang; Zhang, Yu-Jing; He, Ji-Zheng

    2018-04-24

    Antibiotic resistance is ancient and prevalent in natural ecosystems and evolved long before the utilization of synthetic antibiotics started, but factors influencing the large-scale distribution patterns of natural antibiotic resistance genes (ARGs) remain largely unknown. Here, a large-scale investigation over 4000 km was performed to profile soil ARGs, plant communities and bacterial communities from 300 quadrats across five forest biomes with minimal human impact. We detected diverse and abundant ARGs in forests, including over 160 genes conferring resistance to eight major categories of antibiotics. The diversity of ARGs was strongly and positively correlated with the diversity of bacteria, herbaceous plants and mobile genetic elements (MGEs). The ARG composition was strongly correlated with the taxonomic structure of bacteria and herbs. Consistent with this strong correlation, structural equation modelling demonstrated that the positive effects of bacterial and herb communities on ARG patterns were maintained even when simultaneously accounting for multiple drivers (climate, spatial predictors and edaphic factors). These findings suggest a paradigm that the interactions between aboveground and belowground communities shape the large-scale distribution of soil resistomes, providing new knowledge for tackling the emerging environmental antibiotic resistance. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Microbial quality of soil from the Pampa biome in response to different grazing pressures

    Directory of Open Access Journals (Sweden)

    Rafael S. Vargas

    2015-06-01

    Full Text Available The aim of this study was to evaluate the impact of different grazing pressures on the activity and diversity of soil bacteria. We performed a long-term experiment in Eldorado do Sul, southern Brazil, that assessed three levels of grazing pressure: high pressure (HP, with 4% herbage allowance (HA, moderate pressure (MP, with 12% HA, and low pressure (LP, with 16% HA. Two reference areas were also assessed, one of never-grazed native vegetation (NG and another of regenerated vegetation after two years of grazing (RG. Soil samples were evaluated for microbial biomass and enzymatic (β-glucosidase, arylsulfatase and urease activities. The structure of the bacterial community and the population of diazotrophic bacteria were evaluated by RFLP of the 16S rRNA and nifH genes, respectively. The diversity of diazotrophic bacteria was assessed by partial sequencing of the 16S rDNA gene. The presence of grazing animals increased soil microbial biomass in MP and HP. The structures of the bacterial community and the populations of diazotrophic bacteria were altered by the different grazing managements, with a greater diversity of diazotrophic bacteria in the LP treatment. Based on the characteristics evaluated, the MP treatment was the most appropriate for animal production and conservation of the Pampa biome.

  13. Termite assemblages in five semideciduous Atlantic Forest fragments in the northern coastland limit of the biome

    Directory of Open Access Journals (Sweden)

    Heitor Bruno de Araújo Souza

    2012-03-01

    Full Text Available Termites are abundant organisms in tropical ecosystems and strongly influence the litter decomposition and soil formation. Despite their importance, few studies about their assemblage structures have been made in Brazilian Atlantic Forest fragments, especially in the area located north of the São Francisco River. This study aims to analyze the assemblage composition of five Atlantic Forest fragments located in the northern biome limit along the Brazilian coast. A standardized sampling protocol of termites was applied in each fragment. Thirty-three termite species belonging to twenty genera and three families were found in the forest fragments. The wood-feeder group was dominant both concerning to species richness and number of encounters in all areas. In sites northern to 7°S, there is an evident simplification of the termite assemblage composition regarding species richness and number of encounters by feeding group. This fact is apparently due to a higher sandy level in soils and to semideciduous character of the vegetation in the northern fragments. Thus, even on the north of São Francisco River, termite biodiversity is heterogeneously spread with highest density of species in the portion between 07°S and São Francisco River mouth (10°29'S.

  14. Methane Production and Transport within the Marsh Biome of Biosphere 2

    Science.gov (United States)

    Molnar, Jennifer; Goodridge, Kelven

    1997-01-01

    In recent decades, the concentration of methane in the earth's atmosphere increased 1-2% annually. It's rate of increases, combined with methane's effectiveness as a greenhouse gas, has led to an intensive research effort to determine the sources and sinks of the gas in the environment. Biosphere 2 offers a unique opportunity to contribute to the effort because it lacks a major photochemical sink present in the Earth's atmosphere. Researchers can therefore concentrate on biological processes involved in methane cycles. Wetlands are a large source of atmospheric methane, due to anoxic conditions in the sediments and the abundance of organic materials. In order to determine if these conditions in Biosphere 2 also promote methane production, this study looked for the fluxes of methane and methods of transport of the gas from from the water and sediments to the atmosphere in the Marsh Biome. Fluxes of methane from the sediments and waters were measured using static chambers, peepers, and leaf bags. Fluxes and vertical profiles of methane in the sediments show that substantial amounts of methane are being produced in the marsh and are being transported into the Biosphere 2 environment.

  15. Beyond aridification: multiple explanations for the elevated diversification of cacti in the New World Succulent Biome.

    Science.gov (United States)

    Hernández-Hernández, Tania; Brown, Joseph W; Schlumpberger, Boris O; Eguiarte, Luis E; Magallón, Susana

    2014-06-01

    Succulent plants are widely distributed, reaching their highest diversity in arid and semi-arid regions. Their origin and diversification is thought to be associated with a global expansion of aridity. We test this hypothesis by investigating the tempo and pattern of Cactaceae diversification. Our results contribute to the understanding of the evolution of New World Succulent Biomes. We use the most taxonomically complete dataset currently available for Cactaceae. We estimate divergence times and utilize Bayesian and maximum likelihood methods that account for nonrandom taxonomic sampling, possible extinction scenarios and phylogenetic uncertainty to analyze diversification rates, and evolution of growth form and pollination syndrome. Cactaceae originated shortly after the Eocene-Oligocene global drop in CO2 , and radiation of its richest genera coincided with the expansion of aridity in North America during the late Miocene. A significant correlation between growth form and pollination syndrome was found, as well as a clear state dependence between diversification rate, and pollination and growth-form evolution. This study suggests a complex picture underlying the diversification of Cactaceae. It not only responded to the availability of new niches resulting from aridification, but also to the correlated evolution of novel growth forms and reproductive strategies. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  16. Effect of postharvest practices including degreening on citrus carpoplane microbial biomes.

    Science.gov (United States)

    Gomba, A; Chidamba, L; Korsten, L

    2017-04-01

    To investigate the effect of commercial citrus packhouse processing steps on the fruit surface microbiome of Clementines and Palmer navel oranges. Viable bacteria, yeast and fungi counts, and the pyrosequencing analysis of the 16S rRNA and ITS were used to evaluate the community structure and population dynamics of phylloepiphytic bacteria and fungi associated with commercial postharvest processing. Drenching significantly reduced microbial counts in all cases except for yeasts on navels, while the extent of degreening effects varied between the citrus varieties. Pyrosequencing analysis showed a total of 4409 bacteria and 5792 fungi nonchimeric unique sequences with an average of 1102 bacteria and 1448 fungi reads per sample. Dominant phyla on the citrus carpoplane were Proteobacteria (53·5%), Actinobacteria (19·9%), Bacteroidetes (5·6%) and Deinococcus-Thermus (5·4%) for bacteria and Ascomycota (80·5%) and Basidiomycota (9·8%) for fungi. Beginning with freshly harvested fruit fungal diversity declined significantly after drenching, but had little effect on bacteria and populations recovered during degreening treatments, including those for Penicillium sp. Packhouse processing greatly influences microbial communities on the citrus carpoplane. A broad orange biome was described with pyrosequencing and gave insight into the likely survival and persistence of pathogens, especially as they may affect the quality and safety of the packed product. A close examination of the microbiota of fruit and the impact of intervention strategies on the ecological balance may provide a more durable approach to reduce losses and spoilage. © 2017 The Society for Applied Microbiology.

  17. Antimicrobial potential of actinobacteria isolated from the rhizosphere of the Caatinga biome plant Caesalpinia pyramidalis Tul.

    Science.gov (United States)

    Silva-Lacerda, G R; Santana, R C F; Vicalvi-Costa, M C V; Solidônio, E G; Sena, K X F R; Lima, G M S; Araújo, J M

    2016-03-04

    Actinobacteria are known to produce various secondary metabolites having antibiotic effects. This study assessed the antimicrobial potential of actinobacteria isolated from the rhizosphere of Caesalpinia pyramidalis Tul. from the Caatinga biome. Sixty-eight actinobacteria isolates were evaluated for antimicrobial activity against different microorganisms by disk diffusion and submerged fermentation, using different culture media, followed by determination of minimum inhibitory concentration (MIC) and chemical prospecting of the crude extract. Of the isolates studied, 52.9% of those isolated at 37°C and 47.05% of those isolated at 45°C had activity against Bacillus subtilis, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Fusarium moniliforme, and Candida albicans. When compared with others actinobacteria, the isolate C1.129 stood out with better activity and was identified by 16S rDNA gene analysis as Streptomyces parvulus. The crude ethanol extract showed an MIC of 0.97 μg/mL for MRSA and B. subtilis, while the ethyl acetate extract showed MIC of 3.9 μg/mL for S. aureus and MRSA, showing the greatest potential among the metabolites produced. Chemical prospecting revealed the presence of mono/sesquiterpenes, proanthocyanidin, triterpenes, and steroids in both crude extracts. This study evaluates S. parvulus activity against multi-resistant microorganisms such as MRSA. Thus, it proves that low-fertility soil, as is found in the Caatinga, may contain important microorganisms for the development of new antimicrobial drugs.

  18. Specialist plant species harbour higher reproductive performances in recently restored calcareous grasslands than in reference habitats

    OpenAIRE

    Harzé, Mélanie; Mahy, Grégory; Bizoux, Jean-Philippe; Piqueray, Julien; Monty, Arnaud

    2015-01-01

    Background and aims_Calcareous grasslands are local biodiversity hotspots in temperate regions that suffered intensive fragmentation. Ecological restoration projects took place all over Europe. Their success has traditionally been assessed using a plant community approach. However, population ecology can also be useful to assess restoration success and to understand underlying mechanisms. Methods_We took advantage of three calcareous grassland sites in Southern Belgium, where reference p...

  19. Extensive Management Promotes Plant and Microbial Nitrogen Retention in Temperate Grassland

    Science.gov (United States)

    de Vries, Franciska T.; Bloem, Jaap; Quirk, Helen; Stevens, Carly J.; Bol, Roland; Bardgett, Richard D.

    2012-01-01

    Leaching losses of nitrogen (N) from soil and atmospheric N deposition have led to widespread changes in plant community and microbial community composition, but our knowledge of the factors that determine ecosystem N retention is limited. A common feature of extensively managed, species-rich grasslands is that they have fungal-dominated microbial communities, which might reduce soil N losses and increase ecosystem N retention, which is pivotal for pollution mitigation and sustainable food production. However, the mechanisms that underpin improved N retention in extensively managed, species-rich grasslands are unclear. We combined a landscape-scale field study and glasshouse experiment to test how grassland management affects plant and soil N retention. Specifically, we hypothesised that extensively managed, species-rich grasslands of high conservation value would have lower N loss and greater N retention than intensively managed, species-poor grasslands, and that this would be due to a greater immobilisation of N by a more fungal-dominated microbial community. In the field study, we found that extensively managed, species-rich grasslands had lower N leaching losses. Soil inorganic N availability decreased with increasing abundance of fungi relative to bacteria, although the best predictor of soil N leaching was the C/N ratio of aboveground plant biomass. In the associated glasshouse experiment we found that retention of added 15N was greater in extensively than in intensively managed grasslands, which was attributed to a combination of greater root uptake and microbial immobilisation of 15N in the former, and that microbial immobilisation increased with increasing biomass and abundance of fungi. These findings show that grassland management affects mechanisms of N retention in soil through changes in root and microbial uptake of N. Moreover, they support the notion that microbial communities might be the key to improved N retention through tightening linkages

  20. Energy production from grassland - Assessing the sustainability of different process chains under German conditions

    International Nuclear Information System (INIS)

    Roesch, Christine; Skarka, J.; Raab, K.; Stelzer, V.

    2009-01-01

    In many regions of Europe, grassland shapes the landscape and fulfils important functions in protecting nature, soil, and water. However, the traditional uses of grassland for forage production are vanishing with progress in breeding and structural adaptations in agriculture. On the other hand, the demand for biomass energy is rising due to political sustainability goals and financial measures to support renewable energy. Against this background, the Institute for Technology Assessment and Systems Analysis investigated the applicability, economic efficiency, and sustainability of different techniques for energy production from grassland as well as from grassland converted into maize fields or short-rotation poplars under German conditions. The results show that despite relatively high energy prices and the financial support for bioenergy, the effects of energy production from grassland on employment in agriculture and farmers' income are modest. What is beneficial are savings in non-renewable energy, reductions in greenhouse gas emissions, and local provision of energy carriers. If grassland biomass (grass silage or hay) is used for energy purposes, this brings the further advantages of preserving biodiversity and the cultural landscape and protecting of soil and groundwater. Negative impacts on sustainable development result from an increase in emissions, which leads to acidification, eutrophication, and risks to human health. The overall evaluation indicates that short-rotation poplars are comparatively advantageous from the economic and ecological point of view. Therefore, a development plan for grassland is required to identify areas where grassland could be used as an energy resource or where it would be favourable to install energy plantations with fast-growing perennial plants