Extreme drought impacts have been underestimated in grasslands and shrublands globally

Published in: Proceedings of the National Academy of Sciences of the United States of America

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

Significance

Drought has well-documented societal and economic consequences. Climate change is expected to intensify drought to even more extreme levels, but because such droughts have been historically rare, their impact on ecosystem functioning is not well known.

We experimentally imposed the most frequent type of intensified drought—one that is ~1 y in duration—at 100 grassland and shrubland sites distributed across six continents.

We found that loss of aboveground plant growth, a key measure of ecosystem function, was 60% greater when short-term drought was extreme (≤1-in-100-y historical occurrence).

This drought-induced loss in function greatly exceeds previously reported losses for grasslands and shrublands, suggesting that the global impacts of projected increases in drought severity have been substantially underestimated.

Abstract

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.

Smith MD, Wilkins KD, Holdrege MC, Wilfahrt P, Collins SL, Knapp AK, Sala OE, Dukes JS, Phillips RP, Yahdjian L, Gherardi LA, Ohlert T, Beier C, Fraser LH, Jentsch A, Loik ME, Maestre FT, Power SA, Yu Q, Felton AJ, Munson SM, Luo Y, Abdoli H, Abedi M, Alados CL, Alberti J, Alon M, An H, Anacker B, Anderson M, Auge H, Bachle S, Bahalkeh K, Bahn M, Batbaatar A, Bauerle T, Beard KH, Behn K, Beil I, Biancari L, Blindow I, Bondaruk VF, Borer ET, Bork EW, Bruschetti CM, Byrne KM, Cahill JF Jr, Calvo DA, Carbognani M, Cardoni A, Carlyle CN, Castillo-Garcia M, Chang SX, Chieppa J, Cianciaruso MV, Cohen O, Cordeiro AL, Cusack DF, Dahlke S, Daleo P, D’Antonio CM, Dietterich LH, S Doherty T, Dubbert M, Ebeling A, Eisenhauer N, Fischer FM, Forte TGW, Gebauer T, Gozalo B, Greenville AC, Guidoni-Martins KG, Hannusch HJ, Vatsø Haugum S, Hautier Y, Hefting M, Henry HAL, Hoss D, Ingrisch J, Iribarne O, Isbell F, Johnson Y, Jordan S, Kelly EF, Kimmel K, Kreyling J, Kröel-Dulay G, Kröpfl A, Kübert A, Kulmatiski A, Lamb EG, Larsen KS, Larson J, Lawson J, Leder CV, Linstädter A, Liu J, Liu S, Lodge AG, Longo G, Loydi A, Luan J, Curtis Lubbe F, Macfarlane C, Mackie-Haas K, Malyshev AV, Maturano-Ruiz A, Merchant T, Metcalfe DB, Mori AS, Mudongo E, Newman GS, Nielsen UN, Nimmo D, Niu Y, Nobre P, O’Connor RC, Ogaya R, Oñatibia GR, Orbán I, Osborne B, Otfinowski R, Pärtel M, Penuelas J, Peri PL, Peter G, Petraglia A, Picon-Cochard C, Pillar VD, Piñeiro-Guerra JM, Ploughe LW, Plowes RM, Portales-Reyes C, Prober SM, Pueyo Y, Reed SC, Ritchie EG, Rodríguez DA, Rogers WE, Roscher C, Sánchez AM, Santos BA, Cecilia Scarfó M, Seabloom EW, Shi B, Souza L, Stampfli A, Standish RJ, Sternberg M, Sun W, Sünnemann M, Tedder M, Thorvaldsen P, Tian D, Tielbörger K, Valdecantos A, van den Brink L, Vandvik V, Vankoughnett MR, Guri Velle L, Wang C, Wang Y, Wardle GM, Werner C, Wei C, Wiehl G, Williams JL, Wolf AA, Zeiter M, Zhang F, Zhu J, Zong N, Zuo X (2024) Extreme drought impacts have been underestimated in grasslands and shrublands globally. Proceedings of the National Academy of Sciences of the United States of America PDF DOI