Prediction of suitable overwintering habitat for Grus grus and key factors influencing population distribution in China.

Abstract

Common cranes (Grus grus) are large wading birds widely distributed across China, with populations showing an increasing trend. Identifying the key factors influencing the suitable overwintering habitats and population distribution of G. grus is essential for guiding species conservation. We employed the MaxEnt model to predict the suitable overwintering habitats of G. grus in China, using 300 distribution points from the overwintering period and incorporating 26 ecological factors, including climate, topography, land use, normalized difference vegetation index, and human disturbance. The results showed that the primary factors influencing the selection of overwintering habitats for the eastern population of G. grus included elevation, distance to water sources, precipitation of the driest quarter, and temperature seasonality. For the central population, distance to water sources, precipitation of the coldest quarter, elevation, mean temperature of the coldest quarter, and distance to villages were the key factors. Isothermality, distance to villages, elevation, and distance to water sources were the key factors influencing the western population. The area of highly suitable overwintering habitats for G. grus in eastern China was 33730.91 km², primarily located in the North China Plain and the wetlands of the middle and lower Yangtze River. In central China, the area was 19336.81 km², mainly found in the wetlands of the Yellow River in Shanxi, Shaanxi, and Henan. In western China, the area was 52243.06 km², predominantly distributed in the wetlands and cropland-mosaic areas of southern Xizang, northern Yunnan, and western Guizhou. Suitable habitats for G. grus were found across nearly all of China, with the species exhibiting adaptability to harsh environments, such as high-altitude and high-latitude areas. Our results could provide guidance for the conservation and management of G. grus.