Search

Los espacios protegidos, por el hecho de albergar una gran geo-biodiversidad y asegurar una baja intervención humana, constituyen lugares muy adecuados para el seguimiento de organismos y procesos a escala ecológica, así como para la obtención de series temporales largas a escala geológica. En el marco de la red LTER-España, el Parque Nacional de Ordesa y Monte Perdido (PNOMP) y el Instituto Pirenaico de Ecología-CSIC están impulsando estudios para la detección de cambios a distintas escalas mediante variados métodos y aproximaciones. Destacamos aquí los más consolidados, entre los que se encuentran los análisis de registros de sedimentos en lagos, espeleotemas en cuevas, la dinámica de uno de los pocos glaciares activos de la Península ibérica, el análisis físico-químico de aguas corrientes e ibones de alta montaña, el registro del cambio climático actual en árboles longevos, la afección que éste ejerce sobre masas actuales de pinos en el límite superior del bosque y de abetales en zonas húmedas, la matorralización de algunos pastos y los procesos mecanicistas que subyacen, la reorganización de la diversidad florística en pastos tras el abandono paulatino o drástico de la ganadería, la biodiversidad de las comunidades alpinas y la dinámica poblacional de especies amenazadas o indicadoras de hábitats o de motores de cambio global. Los seguimientos ecológicos actuales muestran que tanto el cambio climático como el de usos del suelo están teniendo una considerable trascendencia en la fisionomía y la estructura de algunos de los ambientes más icónicos y frecuentes del parque (deterioro del glaciar, termofilización de la flora en cumbres alpinas, densificación del bosque en su límite superior, pérdida de productividad en algunos pastos supraforestales, etc.). También sugieren una importante variabilidad espacial en los procesos (por ej. en el PNOMP conviven pastos matorralizados y pastos muy estables), y evidencian que los cambios observados no siempre siguen los paradigmas establecidos (por ej., las especies amenazadas mantienen dinámicas poblacionales estables). La integración de resultados parciales proporcionados por cada aproximación relativiza la importancia de las percepciones que cada estudio destaca por separado, y permite medir los cambios actuales en el marco de referencia de los cambios a escala geológica. Predecir la resistencia y resiliencia de los ecosistemas o las poblaciones de seres vivos para enfrentarse a los futuros cambios ambientales es complicado, no sólo por la falta de conocimientos disponibles sino también porque las respuestas que observamos no siempre son tan rápidas o lineales como se espera. La modelización constituye una herramienta cada vez más utilizada, pero requiere de evidencias reales para validar sus pronósticos, por lo que la observación de los procesos que actúan en el PNOMP ha de incluir un esfuerzo continuado de monitorización multiescalar y multidisciplinar de los distintos componentes de la geo, hidro-, crio- y biosfera, sin olvidar el componente humano. Entender la complejidad supone conectar las interacciones que existen entre todos los sistemas y ponderar sus efectos según las escalas de trabajo., Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas, España, Empresa pública SARGA, España, JOLUBE Consultor Botánico, Editor y Fotógrafo, España, Departament d’Ecologia, Universitat de Barcelona, España, Unidad de Tres Cantos, Instituto Geológico y Minero de España, España, Institut de Recerca de Biodiversitat, Universitat de Barcelona, España, Parque Nacional de Ordesa y Monte Perdido, España

1. Plant diversity supports multiple ecosystem functions, including carbon sequestration. Recent shifts in plant diversity in rangelands due to increased grazing pressure and climate changes have the potential to impact the sequestration of carbon in arid to semi-humid regions worldwide. However, plant diversity, grazing intensity and carbon storage are also influenced by environmental factors such as nutrient availability, climate, and topography. The complexity of these interactions limits our ability to fully assess the impacts of grazing on biodiversity-ecosystem function (BEF) relationships. 2. We assessed how grazing intensity modifies BEF relationships by determining the links between plant diversity and ecosystem carbon stocks (plant and soil carbon) across broad environmental gradients and different plant growth forms. To achieve this, we surveyed 1493 quadrats across 10 rangelands, covering an area of 23,756 ha in northern Iran. 3. We show that aboveground carbon stocks increased with plant diversity across topographic, climatic and soil fertility gradients. The relationship between aboveground carbon stocks and plant diversity was strongest for forbs, followed by shrubs and grasses. Soil carbon stocks increased strongly with soil fertility across sites, but aridity, grazing, plant diversity and topography were also important in explaining variation in soil carbon stocks. 4. Importantly, aboveground and soil carbon stocks declined at high grazing intensity, and grazing modified the relationship between plant diversity and carbon stocks regardless of differences in abiotic conditions across sites. 4. Our study demonstrates that relationships between plant diversity and ecosystem carbon stocks persist across gradients of aridity, topography, and soil fertility, but the relationships are modified by grazing intensity. Our findings suggest that potential losses in plant diversity under grazing intensification could reduce ecosystem carbon storage across wide areas of arid to semi-humid rangelands. We discuss the potential mechanisms underpinning rangeland BEF relationships to stimulate future research., We would like to thank all of those involved in this research and who helped with the fieldwork. A. Sanaei is supported by the Saxon State Ministry for Science, Culture and Tourism (SMWK) – [3-7304/35/6-2021/48880]. Z. Yuan is supported by the National Natural Science Foundation of China (32171581) and the Fundamental Research Funds for the Central Universities. H. Saiz is supported by a María Zambrano fellowship funded by the Ministry of Universities and European Union-Next Generation plan. M. Delgado-Baquerizo is supported by a Ramón y Cajal grant (RYC2018-025483-I), a project from the Spanish Ministry of Science and Innovation (PID2020-115813RA-I00), and a project PAIDI 2020 from the Junta de Andalucía (P20_00879). A. Ali is supported by the faculty start-up research funding program at Hebei University for developing the Forest Ecology Research Group (Special Project No. 521100221033)

7 páginas.- 4 figuras.- 32 referencias.- Supplementary materials: science.org/doi/10.1126/science.abq4062 Materials and Methods Figs. S1 to S19 Tables S1 to S28 References (33–269) MDAR Reproducibility Checklist Movie S1.- Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and speciespoor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure. Copyright © 2022 the authors, Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and species-poor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure. Copyright © 2022 the authors, Funding: This research was funded by the European Research Council [ERC grant agreement 647038 (BIODESERT)] and Generalitat Valenciana (CIDEGENT/2018/ 041). F.T.M. acknowledges support from a Rei Jaume I Award, the Alexander von Humboldt Foundation, and the Synthesis Center (sDiv) of the German Centre for Integrative Biodiversity Research Halle–Jena–Leipzig (iDiv). C.A.G., S.C., and N.E. acknowledge support from iDiv and the Deutsche Forschungsgemeinschaft (DFG– FZT 118, 202548816; Flexpool proposal 34600850). Y.L.B.-P. was supported by a Marie Sklodowska-Curie Actions Individual Fellowship (MSCA-IF) within the European Program Horizon 2020 (DRYFUN Project 656035). N.G. was supported by CAP 20-25 (16-IDEX-0001) and the AgreenSkills+ fellowship program, which has received funding from the EU’s Seventh Framework Programme under grant agreement N° FP7-609398 (AgreenSkills+ contract). B.B. and B.E. were supported by the Taylor Family–Asia Foundation Endowed Chair in Ecology and Conservation Biology. J.D., A.Ro., and H.C. acknowledge support from the Fundação para a Ciência e a Tecnologia (IF/00950/ 2014 and 2020.03670.CEECIND, SFRH/BDP/108913/2015, and in the scope of the framework contract foreseen in the numbers 4-6 of the article 23, of the Decree-Law 57/2016, August 29, changed by Law 57/2017, July 19, respectively), as well as from the MCTES, FSE, UE, and the CFE (UIDB/04004/2020) research unit financed by Fundação para a Ciência e a Tecnologia/MCTES through national funds (PIDDAC). C.P. acknowledges support from the Spanish Ministry of Science and Innovation (ref. AGL201675762-R, AEI/FEDER, UE, and PID2020-116578RB-I00, MCIN/AEI/10.13039/501100011033) and the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement no. 101000224. E.V. was funded by the 2017 program for attracting and retaining talent of Comunidad de Madrid (no. 2017‐T2/ AMB‐5406). M.A.B. acknowledges support from the School of Forestry and College of the Environment, Forestry and Natural Sciences of Northern Arizona University. E.H.-S. acknowledges support from the Consejo Nacional de Ciencia y Tecnología (SEP-CB-2015-01-251388, PN 2017-5036 and PRONAII 319059). F.M.H. acknowledges support from the National Council for Scientific and Technological Development (CNPq - PCI/INMA) of the Brazilian Ministry of Science, Technology and Innovation (MCTI, processes number 302381/2020-1). H.L.T. acknowledges support from the US National Science Foundation (NSF) (DEB 0953864). A.N. and M.K. acknowledge support from the Fundação para a Ciência e a Tecnologia (SFRH/BD/130274/2017, CEECIND/02453/2018/CP1534/CT0001, PTDC/ASP-SIL/7743/2020 and UIDB/00329/2020). A.A.C. acknowledges support from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. J.E.K. and T.P.M. acknowledge the National Research Foundation of South Africa (grant no. 114412). F.J. and N.B. acknowledge support from the German Federal Ministry of Education and Research (BMBF) in the framework of the SPACES projects OPTIMASS (FKZ: 01LL1302A) and ORYCS (FKZ:01LL1804A). A.Li. and A.S.K.F. acknowledge support from the German Federal Ministry of Education and Research (BMBF) in the framework of the SPACES projects Limpopo Living Landscapes (FKZ: 01LL1304D) and SALLnet (FKZ: 01LL1802C). L.W. acknowledges support from the US NSF (EAR 1554894). L.H.F. acknowledges support from the Natural Sciences and Engineering Research Council of Canada Industrial Research Chair Program in Ecosystem Reclamation. S.C.R. acknowledges support from the US Geological Survey Ecosystems Mission Area and the US Bureau of Land Management. G.M.W. acknowledges support from the Australian Research Council. L.v.d.B. and K.T. acknowledge support from the German Research Foundation (DFG) priority research program SPP-1803 “EarthShape: Earth Surface Shaping by Biota” (TI 338/14-1). M.D.-B. acknowledges support from the Spanish Ministry of Science and Innovation for the I+D+i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D.-B. is also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014-2020 Objetivo temático “01 - Refuerzo de la investigación, el desarrollo tecnológico y la innovación”) associated with the research project P20_00879 (ANDABIOMA). P.J.R. and A.J.M. acknowledge support from Fondo Europeo de Desarrollo Regional through the FEDER Andalucía operative program, FEDER-UJA 1261180 project. A.F. thanks ANID PIA/BASAL FB210006 and Millennium Science Initiative Program NCN2021-050. A.J. acknowledges support from the Bavarian Research Alliance Germany (BayIntAn_UBT_2017_61). C.B. acknowledges the National Natural Science Foundation of China (grant no. 41971131). Biodiversity and ecosystem function research in the B.K.S. laboratory is funded by the Australian Research Council (DP210102081). Any use of trade, product, or firm names in this paper is for descriptive purposes only and does not imply endorsement by the US government. H.S. is supported by a María Zambrano fellowship funded by the Ministry of Universities and European Union-Next Generation plan. G.P. and C.V.L. acknowledge support from Universidad Nacional de Río Negro (PI 40-C-873 and 654). V.R. acknowledges support from the Regional Government of Extremadura (Spain) through a “Talento” fellowship (TA18022). M.F. acknowledges support from the Department of Range and Watershed Management, Ferdowsi University of Mashhad, Mashhad, Iran. Participation of recent graduates in collecting field data at four sites in Namibia was supported by a capacity building grant to Gobabeb–Namib Research Institute by the Environmental Investment Fund in Namibia.