Nährstoffanreicherung, Veränderungen in Beweidung und Klimawandel wirken sich weltweit auf Zusammensetzung und Vielfalt von Pflanzengemeinschaften aus. Ich untersuchte interaktive Auswirkungen dieser abiotischen und biotischen Veränderungen sowie Mechanismen, insbesondere Konkurrenz um Licht, um zu verstehen, warum sich die Zusammensetzung von Pflanzengemeinschaften verändert und Vielfalt abnimmt. In Feldexperimenten in Finnland und Deutschland untersuchte ich intraspezifische Merkmale, Leistung und Rekrutierung von Pflanzen. Ich fand heraus, dass Weidetiere die Reaktionen von intraspezifischen Merkmalen und Leistung auf Düngung und Klimawandel beeinflussen. Ich stellte fest, dass Anhäufung von Streu, nicht aber Lichtlimitation, frühe Rekrutierung hemmt. Die Ausprägung von Merkmalen als Reaktion auf Konkurrenz um Licht war von Merkmalen und Behandlung abhängig. Diese Arbeit unterstreicht die Schlüsselrolle des Weidemanagements für Pflanzengemeinschaften unter aktuellem globalem Wandel.
Temporal stability of ecosystem functioning increases the predictability and reliability of ecosystem services, and understanding the drivers of stability across spatial scales is important for land management and policy decisions. We used species-level abundance data from 62 plant communities across five continents to assess mechanisms of temporal stability across spatial scales. We assessed how asynchrony (i.e. different units responding dissimilarly through time) of species and local communities stabilised metacommunity ecosystem function. Asynchrony of species increased stability of local communities, and asynchrony among local communities enhanced metacommunity stability by a wide range of magnitudes (1–315%); this range was positively correlated with the size of the metacommunity. Additionally, asynchronous responses among local communities were linked with species' populations fluctuating asynchronously across space, perhaps stemming from physical and/or competitive differences among local communities. Accordingly, we suggest spatial heterogeneity should be a major focus for maintaining the stability of ecosystem services at larger spatial scales. ; Fil: Wilcox, Kevin R. Oklahoma State University; Estados Unidos ; Fil: Tredennick, Andrew T. State University of Utah; Estados Unidos ; Fil: Koerner, Sally E. University of North Carolina; Estados Unidos ; Fil: Grman, Emily. Eastern Michigan University; Estados Unidos ; Fil: Hallett, Lauren M. University of Oregon; Estados Unidos ; Fil: Avolio, Meghan L. University Johns Hopkins; Estados Unidos ; Fil: La Pierre, Kimberly J. Smithsonian Environmental Research Center; Estados Unidos ; Fil: Houseman, Gregory R. Wichita State University; Estados Unidos ; Fil: Forest, Isbell. University of Minnesota; Estados Unidos ; Fil: Johnson, David Samuel. Virginia Institute of Marine Science; Estados Unidos ; Fil: Alatalo, Juha M. Qatar University; Qatar ; Fil: Baldwin, Andrew H. University of Maryland; Estados Unidos ; Fil: Bork, Edward W. University of Alberta; Canadá ; Fil: Boughton, Elizabeth H. MacArthur Agroecology Research Center; Estados Unidos ; Fil: Bowman, William D. University of Colorado; Estados Unidos ; Fil: Britton, Andrea J. James Hutton Institute; Estados Unidos ; Fil: Cahill, James F. University of Alberta; Canadá ; Fil: Collins, Scott L. University of New Mexico; Estados Unidos ; Fil: Du, Guozhen. Lanzhou University; China ; Fil: Eskelinen, Anu. Helmholtz Centre for Environmental Research; Alemania. German Centre for Integrative Biodiversity Research; Alemania. University of Oulu; Finlandia ; Fil: Gough, Laura. Towson University; Estados Unidos ; Fil: Jentsch, Anke. University of Bayreuth; Alemania ; Fil: Kern, Christel. United States Forest Service; Estados Unidos ; Fil: Klanderud, Kari. Norwegian University of Life Sciences; Noruega ; Fil: Knapp, Alan K. Colorado State University; Estados Unidos ; Fil: Kreyling, Juergen. Greifswald University; Alemania ; Fil: Luo, Yiqi. Oklahoma State University; Estados Unidos. Northern Arizona University; Estados Unidos. Tsinghua University; China ; Fil: McLaren, James E. University of Texas at El Paso; Estados Unidos ; Fil: Megonigal, Patrick. Smithsonian Environmental Research Center; Estados Unidos ; Fil: Onipchenko, Vladimir. Moscow State Lomonosov University; Rusia ; Fil: Prevéy, Janet. Pacific Northwest Research Station; Estados Unidos ; Fil: Price, Jodi N. Charles Sturt University; Australia ; Fil: Robinson, Clare H. University of Manchester; Reino Unido ; Fil: Sala, Osvaldo Esteban. Arizona State University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina ; Fil: Smith, Melinda D. Colorado State University; Estados Unidos ; Fil: Soudzilovskaia, Nadejda A. Leiden University; Países Bajos ; Fil: Souza, Lara. Oklahoma State University; Estados Unidos ; Fil: Tilman, David. University of Minnesota; Estados Unidos ; Fil: White, Shannon R. Government of Alberta; Canadá ; Fil: Xu, Zhuwen. Chinese Academy of Sciences; República de China ; Fil: Yahdjian, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina ; Fil: Yu, Qiang. Chinese Academy of Agricultural Sciences; China ; Fil: Zhang, Pengfei. Lanzhou University; China ; Fil: Zhang, Yunhai. Chinese Academy of Sciences; República de China. University Aarhus; Dinamarca
Altres ajuts europeus: P.A.W. was additionally supported by the European Union Fourth Environment and Climate Framework Programme (Project Number ENV4-CT970586)P.A.W. was additionally supported by the European Union Fourth Environment and Climate Framework Programme (Project Number ENV4-CT970586). ; The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature-trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.
