Plant–plant interactions can mitigate (or exacerbate) hot drought impacts

Abstract

Plant-plant interactions can mitigate (or exacerbate) hot drought impacts Climate change will increase global surface temperatures by at least another 1.5°C in the next 50 years (IPCC, 2021). This increase in temperature is already accelerating the water cycle and shifting precipitation regimes globally, with some places receiving less precipitation while others are receiving more (IPCC, 2021). Increased global temperatures are also increasing the drying capacity of the atmosphere, measured as vapor pressure deficit (VPD; Yuan et al., 2019). Elevated VPD increases the rate of water loss from soils and plants, thus exacerbating the already negative effects of reduced precipitation. Hotter droughts with elevated VPD can double productivity losses (over just precipitation reductions; Dannenberg et al., 2022) and increase the risk and volatility of fires (Abatzoglou & Williams, 2016). Given the damages already seen during hotter droughts with higher VPD, it is essential that we identify how individual species and ecosystems will respond to hotter droughts in the future. In an article published in this issue of New Phytologist, Mas et al. (2024; 1021-1034 deepen our understanding of how species interactions might mitigate future hot drought effects. Mas et al. demonstrate how hot drought effects can be mitigated by interspecific neighbors for Quercus pubescens but exacerbated by interspecific neighbors for Fagus sylvatica. This work builds upon 30 years of biodiversity research demonstrating that higher diversity ecosystems may be better able to tolerate environmental change. This work also offers an opportunity to explore habitat-specific mechanisms that could drive how different types of ecosystems will respond to drought in the future.