Water addition but not reduction alters plant biomass–diversity relationship

作者：Yan Yu, Josep Peñuelas, Jordi Sardans, Jiu-Ying Pei, Ge Li, G. D. Liu, Jian‐Sheng Ye · 发表于：Global Change Biology · 年份：2024 · DOI：10.1111/gcb.17430 · 被引用次数：28 · 研究领域：Ecology and Vegetation Dynamics Studies、Land Use and Ecosystem Services、Conservation, Biodiversity, and Resource Management

The relationship between plant aboveground biomass and diversity typically follows a unimodal pattern, showing a positive correlation in resource-poor habitats and a negative correlation in resource-rich environments. Precipitation is a crucial resource for both plant biomass and diversity in terrestrial ecosystems. However, the impact of precipitation changes on the relationship between plant biomass and diversity remains unclear. We conduct a water addition field experiment in a semiarid grassland and identify a unimodal relationship between plant biomass and species richness under ambient conditions. Water addition delays the declining phase of this unimodal curve and shift it upward compared to ambient conditions. Our meta-analysis of water addition experiments conducted across major biomes worldwide (grassland, shrubland, desert, and forest) supports this finding, while water reduction does not alter the biomass-diversity relationship. Water addition increases biomass in all climate but only increases species richness in arid and semiarid climate. Similarly, water reduction decreases biomass in all climate but only reduces species richness in arid and semiarid climate. Species richness in dry subhumid and humid climate does not change significantly. Furthermore, our field experiment shows that water addition increases plant diversity while decreasing soil inorganic nitrogen levels. The increase in one resource, such as water, leads to the scarcity of another, such as nut...