Macroscale patterns of rodent herbivory damage and underlying mechanisms in forests of China

Understanding the macroscale patterns of rodent herbivory damage and their driving factors are essential for effective rodent management. This study examines how climatic factors and human activities influence the large-scale spatial distribution of rodent herbivory damage in forests of China.

I utilized a unique long-term province-level dataset of rodent damage in China to map its extent across the country. A generalized linear mixed model was employed to analyze the relationship between rodent damage, and climatic variables, and human population density (HPD). The results reveal a clear spatial pattern of rodent herbivory damage in China's forests, primarily driven by HPD and precipitation of the warmest quarter, with a secondary influence of diurnal temperature range. These three variables explained approximately 58% of the variation in the geographic pattern of rodent herbivory damage in China's forests. Specifically, rodent damage was negatively correlated with both precipitation of the warmest quarter and HPD. Higher precipitation during the warmest quarter (often as rainstorms) probably exacerbates rodent mortality through flooding their burrows and imposing thermal stress, while higher HPD probably increases predation pressure, further lowering rodent populations. Additionally, rodent damage was positively related to diurnal temperature range, likely because greater diurnal temperature fluctuations impose greater thermal stress on their predator, thereby enhancing rodent survival. Consequently, regions in northwestern China that are arid, experience high diurnal temperature fluctuations and have low human populations, are particularly vulnerable to severe rodent damage. In contrast, southern and southeastern China, with higher precipitation, milder temperature fluctuations, and denser human populations, experience significantly lower rodent damage.

The findings suggest that the combination of precipitation during the warmest quarter, diurnal temperature range, and HPD can serve as effective indicators of rodent pest severity in forests. This underscores the need for proactive surveillance and management in arid regions with high diurnal temperature fluctuations and low population densities worldwide.