TY - JOUR T1 - Global change effects on plant communities are magnified by time and the number of global change factors imposed JF - Proceedings of the National Academy of Sciences Y1 - 2019 A1 - Kimberly J. Komatsu A1 - M.L. Avolio A1 - Lemoine, Nathan P. A1 - Isbell, Forest A1 - Grman, Emily A1 - Houseman, Gregory R. A1 - Koerner, Sally E. A1 - Johnson, D.S. A1 - K.R. Wilcox A1 - Juha M. Alatalo A1 - Anderson, J.P. A1 - Aerts, R. A1 - S.G. Baer A1 - Baldwin, Andrew H. A1 - Bates, J. A1 - Beierkuhnlein, C. A1 - Belote, R.T. A1 - John M. Blair A1 - Bloor, J.M.G. A1 - Bohlen, P.J. A1 - Edward W. Bork A1 - Elizabeth H. Boughton A1 - W.D. Bowman A1 - Britton, Andrea J. A1 - Cahill, James F. A1 - Chaneton, Enrique J. A1 - Chiariello, N.R. A1 - Cheng, Jimin. A1 - Scott. L. Collins A1 - Cornelissen, J.H.C. A1 - G. Du A1 - Eskelinen, Anu A1 - Firn, Jennifer A1 - Foster, B. A1 - Gough, L. A1 - Gross, K. A1 - Hallett, L.M. A1 - Han, X. A1 - Harmens, H. A1 - Hovenden, M.J. A1 - Jagerbrand, A. A1 - Jentsch, A. A1 - Kern, Christel A1 - Klanderud, Kari A1 - Alan K. Knapp A1 - Kreyling, Juergen A1 - Li, W. A1 - Luo, Yiqi A1 - McCulley, R.L. A1 - McLaren, Jennie R. A1 - Megonigal, Patrick A1 - J.W. Morgan A1 - Onipchenko, Vladimir A1 - Pennings, S.C. A1 - Prevéy, J.S. A1 - Price, Jodi N. A1 - P.B. Reich A1 - Robinson, Clare H. A1 - Russell, L.F. A1 - Sala, O.E. A1 - Seabloom, E.W. A1 - M.D. Smith A1 - Soudzilovskaia, Nadejda A. A1 - Souza, Lara A1 - K.N. Suding A1 - Suttle, B.K. A1 - Svejcar, T. A1 - Tilman, David A1 - Tognetti, P. A1 - Turkington, R. A1 - White, S. A1 - Xu, Zhuwen A1 - Yahdjian, L. A1 - Yu, Q. A1 - Zhang, Pengfei A1 - Zhang, Yunhai AB -

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously.

VL - 116 UR - https://www.pnas.org/content/early/2019/08/14/1819027116 IS - 36 ER -