Suchergebnisse

The relationship between biodiversity and biomass has been a long standing debate in ecology. Soil biodiversity and biomass are essential drivers of ecosystem functions. However, unlike plant communities, little is known about how the diversity and biomass of soil microbial communities are interlinked across globally distributed biomes, and how variations in this relationship influence ecosystem function. To fill this knowledge gap, we conducted a field survey across global biomes, with contrasting vegetation and climate types. We show that soil carbon (C) content is associated to the microbial diversity–biomass relationship and ratio in soils across global biomes. This ratio provides an integrative index to identify those locations on Earth wherein diversity is much higher compared with biomass and vice versa. The soil microbial diversity-to-biomass ratio peaks in arid environments with low C content, and is very low in C-rich cold environments. Our study further advances that the reductions in soil C content associated with land use intensification and climate change could cause dramatic shifts in the microbial diversity-biomass ratio, with potential consequences for broad soil processes. ; We would like to thank the researchers involved in the CLIMIFUN project for the help with soil sampling. This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 702057. FB and CG thank the Spanish Ministry and FEDER funds for the project AGL2017–85755-R MINECO/AEI/FEDER, UE; the i-LINK + 2018 (LINKA20069) from CSIC, and funds from "Fundación Séneca" from Murcia Province (19896/GERM/15). MD-B is supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I). RDB was supported by NERC Soil Security program grants NE/M017028/1 and NE/P013708/1

Within-field demography of weeds exhibiting wind-mediated long distance seed movement can be largely governed by extra-field seed-source populations. Thus, for these species, a clear understanding of the temporal and spatial patterns of seed dispersal can benefit the development of effective management options. The spatial distribution of the seeds released from the onset of fruiting, in early summer, to the onset of the rainy season, in early autumn, was studied during 2 years at a Mediterranean-climate locality in Erigeron bonariensis L. (Hairy fleabane), a wind-dispersed invasive weed inhabiting ruderal environments and crop fields. Each year, a small source population was established in an open field in SW Spain and seed traps were arranged in the eight cardinal directions at distances up to 100 m (year 1), or in the NE and NW directions at distances up to 65 m (year 2). Counts of trapped seeds were carried out at 4–6 day intervals and the number of seeds released by the source population was estimated each year in most census dates. Four empirical dispersal models based on either thin-tailed or fat-tailed density kernels were tested using year 1 data for their ability to represent the spatial distribution of seeds. To test for anisotropic dispersal, model parameters were allowed to vary according to the wind pattern in each cardinal direction. Based on information criteria, a model including a fat-tailed, Log-hyperbolic secant kernel showing parameter response to the wind pattern, highlighting striking anisotropic dispersal, was selected and evaluated using year 2 data. Distance percentiles 50 and 80 attained by the seed crop released in year 1 season were modeled at 530 m and 10,498 m, respectively. The opposite quadrants encompassing the dominant downwind (N-NE) and upwind directions (S-SW) received 52.5% and 10.8% of seeds. The year 1 population, consisting of 85 plants, generated a modeled seed rain of at least 10 seeds m−2 up to 200 m downwind. Implications of results for management of this herbicide resistance-prone species are discussed. ; DC received a grant from the Spanish Society of Weed Science (SEMh). This work was supported in part by research project C03-017 (PAI-Junta de Andalucía Regional Government, Andalusia, Spain). Funding for open access provided by Universidad de Huelva / CBUA.

The importance of soil age as an ecosystem driver across biomes remains largely unresolved. By combining a cross-biome global field survey, including data for 32 soil, plant, and microbial properties in 16 soil chronosequences, with a global meta-analysis, we show that soil age is a significant ecosystem driver, but only accounts for a relatively small proportion of the cross-biome variation in multiple ecosystem properties. Parent material, climate, vegetation and topography predict, collectively, 24 times more variation in ecosystem properties than soil age alone. Soil age is an important local-scale ecosystem driver; however, environmental context, rather than soil age, determines the rates and trajectories of ecosystem development in structure and function across biomes. Our work provides insights into the natural history of terrestrial ecosystems. We propose that, regardless of soil age, changes in the environmental context, such as those associated with global climatic and land-use changes, will have important long-term impacts on the structure and function of terrestrial ecosystems across biomes. ; This project received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 702057 (CLIMIFUN). M.D.-B. is supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I), and by the BES Grant Agreement No. LRB17\1019 (MUSGONET). F.B. is grateful to the Spanish Ministry and FEDER funds for the project AGL2017–85755-R, the i-LINK+2018 (LINKA20069) from CSIC, and received funds from "Fundación Séneca" from Murcia Province (19896/GERM/15). S.R. was supported by the US Geological Survey Ecosystems Mission Area. C.P. acknowledges support from the Spanish State Plan for Scientific and Technical Research and Innovation (2013–2016), award ref. AGL201675762-R (AEI/FEDER, UE). A.G. acknowledges support from the Spanish Ministry of Science (CGL2017-88124-R). F.A. is supported by FONDECYT 11180538 and S.A. by FONDECYT 1170995. We would like to thank Peter Vitousek for his comments on a previous draft of this paper. Moreover, we thank Matt Gebert, Jessica Henley, Fernando T. Maestre, Victoria Ochoa, and Beatriz Gozalo for their help with lab analyses, and Emilio Guirado for his advice with topographic analyses. We also want to thank Osvaldo Sala, Matthew A. Bowker, Peter Vitousek, Courtney Currier, Martin Kirchmair, Victor M. Peña-Ramírez, Lynn Riedel, Julie Larson, Katy Waechter, David Buckner, and Brian Anacker for their help with soil sampling, and to the City of Boulder Open Space and Mountain Parks for allowing us to conduct these samplings. We are also grateful to the Division of Forestry and Wildlife of the State of Hawai'i and Koke'e State Park for their logistical assistance and for allowing us access to the HA sites. The Arizona research sites were established with the support of an EPA‐STAR Graduate Fellowship (U‐916251), a Merriam‐Powell Center for Environmental Research Graduate Fellowship, an Achievement Rewards for College Scientists (ARCS) Foundation of Arizona Scholarship, and McIntire‐Stennis appropriations to Northern Arizona University and the State of Arizona. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

The importance of soil age as an ecosystem driver across biomes remains largely unresolved. By combining a cross-biome global field survey, including data for 32 soil, plant, and microbial properties in 16 soil chronosequences, with a global meta-analysis, we show that soil age is a significant ecosystem driver, but only accounts for a relatively small proportion of the cross-biome variation in multiple ecosystem properties. Parent material, climate, vegetation and topography predict, collectively, 24 times more variation in ecosystem properties than soil age alone. Soil age is an important local-scale ecosystem driver; however, environmental context, rather than soil age, determines the rates and trajectories of ecosystem development in structure and function across biomes. Our work provides insights into the natural history of terrestrial ecosystems. We propose that, regardless of soil age, changes in the environmental context, such as those associated with global climatic and land-use changes, will have important long-term impacts on the structure and function of terrestrial ecosystems across biomes. ; This project received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 702057 (CLIMIFUN). M.D.-B. is supported by a Ramón y Cajal grant from the Spanish Ministry of Science and Innovation (RYC2018-025483-I), and by the BES Grant Agreement No. LRB17\1019 (MUSGONET). F.B. is grateful to the Spanish Ministry and FEDER funds for the project AGL2017–85755-R, the i-LINK+2018 (LINKA20069) from CSIC, and received funds from "Fundación Séneca" from Murcia Province (19896/GERM/15). S.R. was supported by the US Geological Survey Ecosystems Mission Area. C.P. acknowledges support from the Spanish State Plan for Scientific and Technical Research and Innovation (2013–2016), award ref. AGL201675762-R (AEI/FEDER, UE). A.G. acknowledges support from the Spanish Ministry of Science (CGL2017-88124-R). F.A. is supported by FONDECYT 11180538 and S.A. by FONDECYT 1170995. We would like to thank Peter Vitousek for his comments on a previous draft of this paper. Moreover, we thank Matt Gebert, Jessica Henley, Fernando T. Maestre, Victoria Ochoa, and Beatriz Gozalo for their help with lab analyses, and Emilio Guirado for his advice with topographic analyses. We also want to thank Osvaldo Sala, Matthew A. Bowker, Peter Vitousek, Courtney Currier, Martin Kirchmair, Victor M. Peña-Ramírez, Lynn Riedel, Julie Larson, Katy Waechter, David Buckner, and Brian Anacker for their help with soil sampling, and to the City of Boulder Open Space and Mountain Parks for allowing us to conduct these samplings. We are also grateful to the Division of Forestry and Wildlife of the State of Hawai'i and Koke'e State Park for their logistical assistance and for allowing us access to the HA sites. The Arizona research sites were established with the support of an EPA‐STAR Graduate Fellowship (U‐916251), a Merriam‐Powell Center for Environmental Research Graduate Fellowship, an Achievement Rewards for College Scientists (ARCS) Foundation of Arizona Scholarship, and McIntire‐Stennis appropriations to Northern Arizona University and the State of Arizona. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.