@misc{GuoGuoPangetal., author = {Guo, Tongtian and Guo, Meiqi and Pang, Yue and Sun, Xiangyun and Ryo, Masahiro and Liu, Nan and Zhang, Yingjun}, title = {Ungulate herbivores promote beta diversity and drive stochastic plant community assembly by selective defoliation and trampling: From a four-year simulation experiment}, series = {Journal of Ecology}, volume = {112}, journal = {Journal of Ecology}, number = {9}, publisher = {Wiley}, issn = {0022-0477}, doi = {10.1111/1365-2745.14370}, pages = {1992 -- 2006}, abstract = {1. 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. 2. 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. 3. 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 assembly and impacting species coexistence. Notably, selective defoliation in the Moderate scenario led to a dominance of stochastic processes during community assembly, whereas non-selective defoliation still did not change the dominance of deterministic processes. Further, communities subject to selective defoliation were insensitive to changes in soil properties caused by trampling and excreta return, maintaining a high-level beta diversity and the stochastic of community assembly. 4. Synthesis: Our study provides important insights into the mechanisms by which ungulate herbivores influence plant community assembly, suggesting that defoliation and trampling have the potential to drive stochastic processes, while excreta return plays the opposite role. Our study also suggests that selective foraging by ungulates acts as stronger stochastic forces during community assembly compared to non-selective defoliation. These results imply that considering ungulate feeding preferences and foraging behaviour in grassland management will help prevent biodiversity loss and biotic homogenisation.}, language = {en} } @misc{GuoGuoRyoetal., author = {Guo, Tongtian and Guo, Meiqi and Ryo, Masahiro and Rillig, Matthias C. and Liu, Nan and Zhang, Yingjun}, title = {Ungulate herbivory affects grassland soil biota β-diversity and community assembly via modifying soil properties and plant root traits}, series = {New phytologist : international journal of plant science}, volume = {247}, journal = {New phytologist : international journal of plant science}, number = {1}, publisher = {Wiley}, address = {Oxford}, issn = {0028-646X}, doi = {10.1111/nph.70199}, pages = {281 -- 294}, abstract = {Summary Ungulate herbivory, a widespread and complex disturbance, shapes grassland biodiversity and functions primarily through three mechanisms: defoliation, trampling, and excreta return. However, the specific effects of these mechanisms on soil biodiversity and community assembly remain unclear. We conducted a 4-yr factorial experiment in the Eurasian steppe to investigate how defoliation, trampling, and excreta return influence soil bacterial, fungal, and nematode β-diversity and community assembly under moderate- and high-density ungulate grazing scenarios. Our findings reveal that herbivores affect soil biota through multiple pathways at different grazing intensities. Specifically, selective defoliation in the moderate-density scenario promoted stochastic community assembly of nematodes and fungi by increasing the specific root length of plant communities. Excreta return encouraged stochastic bacterial communities by carbon input, while urine-induced acidification and elevated ammonium levels promoted environmental filtering of bacteria and nematodes. In the high-density scenario, non-selective defoliation and heavy trampling created harsher soil conditions, reducing bacterial and nematode β-diversity via habitat filtering and diminishing association of soil biota with plant roots. This study explored how different components of ungulate behaviour influence soil community assembly and highlighted the crucial role of root traits in mediating soil biota responses, providing insights into the mechanisms of soil biodiversity maintenance under complex disturbances.}, language = {en} }