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Predicted climate change extremes, such as severe or prolonged drought, may considerably impact carbon (C) and nitrogen (N) cycling in water-limited ecosystems. However, we lack a clear and mechanistic understanding of how extreme climate change events impact ecosystem processes belowground. This study investigates the effects of five years of reoccurring extreme growing season drought (66% reduction, extreme drought treatment) and two-month delay in monsoon precipitation (delayed monsoon treatment) on belowground productivity and biogeochemistry in two geographically adjacent semi-arid grasslands: Chihuahuan Desert grassland dominated by Bouteloua eriopoda and Great Plains grassland dominated by B. gracilis. After five years, extreme drought reduced belowground net primary productivity (BNPP) in the Chihuahuan Desert grassland but not in the Great Plains grassland. Across both grasslands, extreme drought increased soil pH and available soil nutrients nitrate and phosphate. The delayed monsoon treatment reduced BNPP in both grasslands. However, while available soil nitrate decreased in the Chihuahuan Desert grassland, the delayed monsoon treatment overall had little effect on soil ecosystem properties. Extreme drought and delayed monsoon treatments did not significantly impact soil microbial biomass, exoenzyme potentials, or soil C stocks relative to ambient conditions. Our study demonstrates that soil microbial biomass and exoenzyme activity in semi-arid grasslands are resistant to five years of extreme and prolonged growing season drought despite changes to soil moisture, belowground productivity, soil pH, and nutrient availability
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This content will become publicly available on July 15, 2027
Biodiversity effects under climate extremes intensify with aridity in grasslands but not forests
Abstract Biodiversity generally enhances ecosystem productivity, but whether such effects persist or intensify during climate extremes is unclear. Here we synthesized data from 75 biodiversity experiments across grasslands and forests to assess how aridity and soil nutrients modulate plant diversity effects under drought and heat extremes. Biodiversity most strongly enhanced productivity under extreme drought in more arid grasslands but had limited effects in forests under such conditions. More arid grasslands showed enhanced complementarity effects under extreme drought, whereas less arid grasslands favoured selection effects driven by productive species. Heat extremes did not produce comparable context-dependent changes in plant diversity effects across ecosystem types or aridity gradients. Soil nutrients did not have any detectable influence under either drought or heat extremes, suggesting that as climatic stress intensifies, hydric limitations override edaphic constraints. Our synthesis identifies when and where plant diversity most strongly enhances productivity, showing that its effects are the greatest under extreme drought in more arid grasslands.
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- PAR ID:
- 10700979
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Nature Ecology & Evolution
- ISSN:
- 2397-334X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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