Environmental filtering outweighs dispersal limitation in shaping the β diversity of grasshopper communities in Southeast Tibet, a biodiversity hotspot

Over the past few decades, research on β diversity has focused largely on plants, mammals, and birds, with relatively few studies on insect β diversity. This study investigated the grasshopper community in Southeast Tibet and analysed the effects of geographic distance and environmental factors on β diversity and its components using climate, soil, and other environmental datasets. The results indicate that the grasshopper community in Southeast Tibet exhibits high β diversity, and the turnover component contributes significantly to β diversity. As geographic and elevational distances increase, both the total β diversity and turnover components significantly increase, whereas the nestedness component decreases. Partial Mantel tests revealed that environmental distance has a significant independent effect on both total β diversity and species turnover components, whereas geographic distance does not have a significant influence on these components. Variance partitioning analysis revealed that environmental selection processes (Total: 14.48%–16.24%; Turnover: 14.79%–16.02%) had a stronger influence on β diversity and turnover components than dispersal limitation (Total: 6.67%–7.74%). The annual mean diurnal temperature range and seasonal precipitation were identified as the most influential environmental factors shaping β diversity and species turnover components in the grasshopper community. In conclusion, environmental filtering, dispersal limitation, and other unidentified processes likely contribute to the β diversity patterns observed in the grasshopper community in Southeast Tibet, with environmental filtering playing a dominant role. These findings provide important insights into the mechanisms driving insect community assembly in mountainous regions.