Extreme drought impacts have been underestimated in grasslands and shrublands globally
Authors: Smith Melinda D. , Wilkins Kate D. , Holdrege Martin C. , Wilfahrt Peter , Collins Scott L. , Knapp Alan K. , Sala Osvaldo E. , Dukes Jeffrey S. , Phillips Richard P. , Yahdjian Laura , Gherardi Laureano A. , Ohlert Timothy , Beier Claus , Fraser Lauchlan H. , Jentsch Anke , Loik Michael E. , Maestre Fernando T. , Power Sally A. , Yu Qiang , Felton Andrew J. , Munson Seth M. , Luo Yiqi , Abdoli Hamed , Abedi Mehdi , Alados Concepción L. , Alberti Juan , Alon Moshe , An Hui , Anacker Brian , Anderson Maggie , Auge Harald , Bachle Seton , Bahalkeh Khadijeh , Bahn Michael , Batbaatar Amgaa , Bauerle Taryn , Beard Karen H. , Behn Kai , Beil Ilka , Biancari Lucio , Blindow Irmgard , Bondaruk Viviana Florencia , Borer Elizabeth T. , Bork Edward W. , Bruschetti Carlos Martin , Byrne Kerry M. , Cahill Jr. James F. , Calvo Dianela A. , Carbognani Michele , Cardoni Augusto , Carlyle Cameron N. , Castillo-Garcia Miguel , Chang Scott X. , Chieppa Jeff , Cianciaruso Marcus V. , Cohen Ofer , Cordeiro Amanda L. , Cusack Daniela F. , Dahlke Sven , Daleo Pedro , D'Antonio Carla M. , Dietterich Lee H. , S. Doherty Tim , Dubbert Maren , Ebeling Anne , Eisenhauer Nico , Fischer Felícia M. , Forte T'ai G. W. , Gebauer Tobias , Gozalo Beatriz , Greenville Aaron C. , Guidoni-Martins Karlo G. , Hannusch Heather J. , Vatsø Haugum Siri , Hautier Yann , Hefting Mariet , Henry Hugh A. L. , Hoss Daniela , Ingrisch Johannes , Iribarne Oscar , Isbell Forest , Johnson Yari , Jordan Samuel , Kelly Eugene F. , Kimmel Kaitlin , Kreyling Juergen , Kröel-Dulay György , Kröpfl Alicia , Kübert Angelika , Kulmatiski Andrew , Lamb Eric G. , Larsen Klaus Steenberg , Larson Julie , Lawson Jason , Leder Cintia V. , Linstädter Anja , Liu Jielin , Liu Shirong , Lodge Alexandra G. , Longo Grisel , Loydi Alejandro , Luan Junwei , Curtis Lubbe Frederick , Macfarlane Craig , Mackie-Haas Kathleen , Malyshev Andrey V. , Maturano-Ruiz Adrián , Merchant Thomas , Metcalfe Daniel B. , Mori Akira S. , Mudongo Edwin , Newman Gregory S. , Nielsen Uffe N. , Nimmo Dale , Niu Yujie , Nobre Paola , O'Connor Rory C. , Ogaya Romà , Oñatibia Gastón R. , Orbán Ildikó , Osborne Brooke , Otfinowski Rafael , Pärtel Meelis , Penuelas Josep , Peri Pablo L. , Peter Guadalupe , Petraglia Alessandro , Picon-Cochard Catherine , Pillar Valério D. , Piñeiro-Guerra Juan Manuel , Ploughe Laura W. , Plowes Robert M. , Portales-Reyes Cristy , Prober Suzanne M. , Pueyo Yolanda , Reed Sasha C. , Ritchie Euan G. , Rodríguez Dana Aylén , Rogers William E. , Roscher Christiane , Sánchez Ana M. , Santos Bráulio A. , Cecilia Scarfó María , Seabloom Eric W. , Shi Baoku , Souza Lara , Stampfli Andreas , Standish Rachel J. , Sternberg Marcelo , Sun Wei , Sünnemann Marie , Tedder Michelle , Thorvaldsen Pål , Tian Dashuan , Tielbörger Katja , Valdecantos Alejandro , van den Brink Liesbeth , Vandvik Vigdis , Vankoughnett Mathew R. , Guri Velle Liv , Wang Changhui , Wang Yi , Wardle Glenda M. , Werner Christiane , Wei Cunzheng , Wiehl Georg , Williams Jennifer L. , Wolf Amelia A. , Zeiter Michaela , Zhang Fawei , Zhu Juntao , Zong Ning , Zuo Xiaoan 
Published: January 2024

Climate change is increasing the frequency and severity of short-term (~1 y) drought events—the most common duration of drought—globally. Yet the impact of this intensification of drought on ecosystem functioning remains poorly resolved. This is due in part to the widely disparate approaches ecologists have employed to study drought, variation in the severity and duration of drought studied, and differences among ecosystems in vegetation, edaphic and climatic attributes that can mediate drought impacts. To overcome these problems and better identify the factors that modulate drought responses, we used a coordinated distributed experiment to quantify the impact of short-term drought on grassland and shrubland ecosystems. With a standardized approach, we imposed ~a single year of drought at 100 sites on six continents. Here we show that loss of a foundational ecosystem function—aboveground net primary production (ANPP)—was 60% greater at sites that experienced statistically extreme drought (1-in-100-y event) vs. those sites where drought was nominal (historically more common) in magnitude (35% vs. 21%, respectively). This reduction in a key carbon cycle process with a single year of extreme drought greatly exceeds previously reported losses for grasslands and shrublands. Our global experiment also revealed high variability in drought response but that relative reductions in ANPP were greater in drier ecosystems and those with fewer plant species. Overall, our results demonstrate with unprecedented rigor that the global impacts of projected increases in drought severity have been significantly underestimated and that drier and less diverse sites are likely to be most vulnerable to extreme drought.