Global change effects on plant communities are magnified by time and the number of global change factors imposed


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.

Publication Type
Journal Article
Kimberly J. Komatsu
Nathan P. Lemoine
Forest Isbell, University of Minnesota
Emily Grman
Gregory R. Houseman
Sally E. Koerner
David S. Johnson
Kevin R. Wilcox
Juha M. Alatalo
John P. Anderson
Rien Aerts
Sara G. Baer
Andrew H. Baldwin
Jonathan Bates
Carl Beierkuhnlein
R. Travis Belote
John Blair
Juliette M.G. Bloor
Patrick J. Bohlen
Edward W. Bork
Elizabeth H. Boughton
William D. Bowman
Andrea J. Britton
James F. Cahill
Enrique Chaneton
Nona R. Chiariello
Jimin Cheng
Scott L. Collins
J. Hans C. Cornelissen
Guozhen Du
Anu Eskelinen
Jennifer Firn
Bryan Foster
Laura Gough
Lauren M. Hallett
Xingguo Han
Harry Harmens
Mark J. Hovenden
Annika Jagerbrand
Anke Jentsch
Christel Kern
Kari Klanderud
Alan K. Knapp
Juergen Kreyling
Wei Li
Yiqi Luo
Rebecca L. McCulley
Jennie R. McLaren
J. Patrick Megonigal
John W. Morgan
Vladimir Onipchenko
Steven C. Pennings
Janet S. Prevéy
Jodi N. Price
Peter B. Reich
Clare H. Robinson
F. Leland Russell
Osvaldo E. Sala
Melinda D. Smith
Nadejda A. Soudzilovskaia
Lara Souza
Katherine Suding
K. Blake Suttle
Tony Svejcar
David Tilman
Pedro Tognetti
Roy Turkington
Shannon White
Zhuwen Xu
Laura Yahdjian
Qiang Yu
Pengfei Zhang
Yunhai Zhang
Proceedings of the National Academy of Sciences