Habitat heterogeneity and topographic variation as the drivers of insect pest distributions in alpine landscapes

Abstract

Insect pests pose a large threat to alpine landscapes, especially under global environmental change conditions. It is necessary to explore the effects of environmental factors on the distribution of pests and provide implications for pest management in alpine landscapes. The main objective of this study was to explore whether habitat heterogeneity and topographic variation could drive insect pest distributions in alpine landscapes. We used species distribution modelling to project the distributions of 58 insect pest species in alpine landscapes based on occurrence records from 5513 field sites and different sets of environmental variables (i.e., climate, climate + habitat heterogeneity, climate + topographic variation, and climate + habitat heterogeneity + topographic variation). Then, we applied the jackknife method to determine the contribution of environmental variables to insect pest distributions. We found that habitat heterogeneity and topographic variation could significantly affect the distribution probability for all insect pest species in Qinghai, China. The response curves of the probability of pest distribution to habitat heterogeneity and topographic variation vary depending on the species present in alpine landscapes. There were four types of response curves of habitat heterogeneity and topographic variation to insect pest distribution probability, namely, 1) increasing, 2) decreasing, 3) increasing and then decreasing, and 4) decreasing and then increasing. Habitat heterogeneity and topographic variation should be integrated into modelling the distributions of insect pest species in alpine landscapes for pest risk assessment.