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Data from: Demographic rate directional change and its determinants reveal how plant species win in a patchy landscape with frequent droughts

Jiang, Peipei12; Wang, Huimin2; Reich, Peter3; Meinzer, Frederick4; Dai, Xiaoqin2; Meng, Shengwang2; Kou, Liang2; Fu, Xiaoli2

Published Aug 04, 2025 on Dryad. https://doi.org/10.5061/dryad.sf7m0cgkd

Data files

Aug 04, 2025 version files 26.50 KB

Abstract

Relative growth rate (RGR) has been a core demographic performance trait in community ecology because its species-specific divergent responses to light often determine community structure and dynamics. Nevertheless, how divergent responses of plant species in RGR to water stress govern community assembly, alongside the mechanistic basis of inter- and intra-specific variations in functional traits, remains elusive. We propose a theoretical framework for describing how directional change of RGR across dry and wet patches drives community assembly in a landscape with frequent droughts. The framework was applied to a subtropical understory shrub community where rock fragment content, an important proxy for water stress, shows strong spatial variability. Our empirical evidence demonstrated that RGR directional change (RGRdir change) was more robust than RGR in wet patches, RGR in dry patches, and the mean RGR in predicting species’ dominance hierarchy. Intraspecific variation in functional traits contributed equally to interspecific variation in mediating shifts in species’ RGRdir change. Species with increasing RGR as substrate water availability decreased were dominant (with higher relative abundance and importance). Dominant species generally had acquisitive roots and hydraulically safe stems. In response to decreasing substrate water availability, dominant species further increased their leaf drought tolerance and optimized root specific length, which not only contributed to their faster radial stem growth but also likely to their release from light competition. Our results highlight the roles of RGR directional change across contrasting water-stress situations in driving community assembly in patchy landscapes with frequent droughts and may improve our understanding of how global climate change-related droughts shape plant community assembly.