高原鼠兔种群密度与生境因子作用关系

Relationship between population density of plateau pika and environmental factors

高原鼠兔(Ochotona curzoniae)是青藏高原上的小型哺乳动物,一定数量内的高原鼠兔可以提高高寒草地的生物多样性,改善土壤结构,有利于维持生态系统的稳定性。但当其种群密度过大时,可能会导致草地退化。探究高原鼠兔种群密度的影响因素能够为科学防控高原鼠兔提供理论依据。本研究从气象、土壤、植被、地形及人类活动多角度探究16个生境因子对高原鼠兔种群密度的影响,通过主成分分析及Pearson相关性分析从16个生境因子中筛选出年均温、植被高度、海拔及土壤硬度为主要建模因子,并采用广义加性模型(GAM)分析高原鼠兔种群密度与4个建模因子之间的作用关系,构建高原鼠兔种群密度预测模型。结果显示:本研究构建的GAM模型拟合度较高(R^(2)=0.946),可以较好地评估青藏高原地区高原鼠兔的潜在致灾风险;土壤硬度与高原鼠兔种群密度之间存在显著负相关;海拔、植被高度和年均温度均与高原鼠兔种群密度之间存在非线性关系,并且海拔为3800~4000 m、植被高度为6~8 cm、年均温度为-2~0℃时高原鼠兔种群密度达到最大。

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(R^(2)=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 3800~4000 m,vegetation height is 6~8 cm,and the average annual temperature is -2~0℃.