Relationship between population density of plateau pika and environmental factors

Plateau pika (Ochotona curzoniae) is a small mammal found on the Qinghai-Tibet Plateau. Some plateau pikas can improve alpine grassland biodiversity, improve soil structure, and help maintain ecosystem stability. However, when population density is too high, grassland degradation may occur. Exploring the factors influencing plateau pika population density can provide a theoretical basis for the scientific prevention and control of plateau pikas. Hence, elucidating the determinants influencing the population density of plateau pikas is beneficial for preventing and managing infestations of plateau rodents. In this study, the effects of 16 habitat factors on the population density of plateau pikas were investigated, including meteorology, soil, topography, vegetation, and human activities. The main modeling factors selected from the 16 habitat factors by principal component analysis and Pearson correlation analysis were annual average temperature, vegetation height, altitude, and soil hardness. The Generalized Additive Model (GAM) was used to establish the population density prediction model for the plateau pika. The results show that the model has a high degree of fit (R² = 0.946). The GAM can assess the potential disaster risk of plateau pikas in the Qinghai-Tibet Plateau with a significant negative correlation between soil density and pika population density. Altitude, vegetation height, and average annual temperature had a nonlinear relationship with the population density of plateau pikas. Moreover, the population density of plateau pika reaches the maximum when the altitude is 3 800～4 000 m, vegetation height is 6～8 cm, and the average annual temperature is −2～0 ℃.