Maxent modeling for predicting suitable habitats for wild ungulates: a case study of typical canyons in the Sanjiangyuan Nature Reserve of China

Abstract

Purpose In the fragmented and isolated Zhongtie Military Protection Area of the Sanjiangyuan National Park, endangered ungulate species—including horse musk deer, blue sheep, and red deer—face significant risks due to habitat degradation and loss, exacerbated by climate change and human activities. This study aims to understand the habitat preferences of ungulates and predict their spatial distributions within the park, contributing to conservation efforts amid climatic shifts. Due to the scarcity of detailed, scientific data on ungulate distributions, populations, and habitats, this study seeks to fill these critical knowledge gaps. Materials and Methods We deployed 55 infrared cameras along the main stream of the Yellow River and in typical canyons on both sides of the China Railway Military Protection Zone within the Sanjiangyuan Nature Reserve. The cameras recorded 2,948 occurrences of ungulates from April to September 2023. We utilized the MaxEnt model to analyze habitat distribution of horse musk deer and blue sheep, incorporating nine environmental variables. Results The model's predictive accuracy, as indicated by the area under the curve (AUC) for Alpine musk deer (0.980) and Blue sheep (0.976), demonstrates its effectiveness. Our analysis identifies climate as the primary influence on habitat distribution, with key factors being annual mean temperature, daily temperature range, altitude, and annual precipitation-contributing to 39.3%, 25.4%, 18.7%, 10.1% for Alpine musk deer, and 40.5%, 23.5%, 14.1%, 11.8% for Blue sheep, respectively. Habitat suitability analysis reveals that 9.61% and 10.84% of the reserve's terrain are viable for Alpine musk deer and Blue sheep, respectively, based on established model thresholds. Conclusions The findings of this study are crucial for the protection of existing wildlife and the identification of potential conservation zones for ungulates. By delineating areas of high habitat suitability, this research supports targeted conservation planning and management efforts within the Sanjiangyuan Reserve, thereby aiding in the sustainable preservation of these endangered species.