Ungulate herbivores promote beta diversity and drive stochastic plant community assembly by selective defoliation and trampling: From a four‐year simulation experiment

作者：Tongtian Guo, Meiqi Guo, Yue Pang, Xiangyun Sun, Masahiro Ryo, Nan Liu, Yingjun Zhang · 发表于：Journal of Ecology · 年份：2024 · DOI：10.1111/1365-2745.14370 · 被引用次数：18 · 研究领域：Ecology and Vegetation Dynamics Studies、Wildlife Ecology and Conservation、Species Distribution and Climate Change

Abstract Ungulate herbivores shape grassland plant communities at multiple scales, ultimately affecting ecosystem function. However, ungulates have complex effects on grasslands, including defoliation, trampling, excreta return and their interactions. Moreover, the effects of ungulate density on grasslands are regulated by these three mechanisms. Nevertheless, how these three mechanisms affect biodiversity at multiple scales and community assembly remains poorly understood. Here, we conducted a 4‐year novel field experiment to disentangle the effects of defoliation, trampling, and excreta return by ungulates on plant community assembly in a temperate grassland in Inner Mongolia, China. This experiment set two different scenarios: moderate ungulate density (Moderate, characterised by selective defoliation and moderate trampling) and high ungulate density (Intense, characterised by non‐selective defoliation and heavy trampling), including different combinations of defoliation, trampling and excreta return in each scenario. We found that defoliation and trampling increased stochasticity in community assembly and promoted alpha and beta diversity under both scenarios. Specifically, defoliation promoted the coexistence of species with multiple resource acquisition strategies (higher functional trait diversity) by reducing interspecific competition; trampling tended to facilitate random species colonisation. Conversely, excreta return favoured grasses, promoting deterministic assem...