基于MaxEnt模型的秦岭山地斑羚生境适宜性评价

Assessment of habitat suitability for Naemorhedus griseus in the Qinling Mountains with MaxEnt model

生境适宜性评价对野生动物的保护与管理具有重要意义。为了解陕西秦岭地区斑羚(Naemorhedus griseus)的生境状况,利用2011-2013年间在秦岭地区采集的斑羚分布点数据,通过MaxEnt模型对陕西秦岭地区的斑羚生境进行适宜性评价。结果表明,陕西秦岭地区的斑羚适宜生境面积约为9800 km^(2),占秦岭山地面积的17%,主要位于秦岭中西部区域;次适宜生境面积约为6940 km^(2),占秦岭面积的12%,主要位于适宜生境的周边区域。海拔、月均昼夜温差和年降雨量是影响陕西秦岭地区斑羚生境适宜性的主要环境变量,而人类干扰对生境适宜性的影响较小。陕西秦岭地区的斑羚偏好于选择1800-3000 m的中高海拔区间、年降水量为750-850 mm、月均昼夜温差8℃左右的环境。明确了斑羚适宜生境在秦岭的分布状况及关键环境影响因子,可为下一步制定濒危动物保护和生境管理提供理论依据。

Habitat assessment is of great importance for effective wildlife conservation and management. Presence-only species distribution models(SDMs), such as the Maximum Entropy(MaxEnt) model, are widely used in ecology and conservation to estimate species-environment relationships and spatial distributions. The Chinese goral(Naemorhedus griseus) is an endangered species and its habitats are fragmented largely caused by human activities. To understand the habitat status of the Chinese goral in the Qinling Mountains of Shaanxi Province, this study evaluated the habitat suitability for the Chinese goral using the MaxEnt with 210 occurrence records and 9 environmental variables. The species occurrences were collected from field investigations carried out in 2011-2013. The environmental variables used for constructing the SDM were elevation, slope, aspect, normalized difference vegetation index, distance to nearest residential area, distance to nearest roads, mean diurnal temperature range, annual precipitation, and precipitation of driest month. The results showed that the areas of suitable habitats and marginal habitats for the Chinese goral were about 9800 km^(2) and 6940 km;in the Qinling Mountains, which accounted for 17% and 12% of the total area, respectively. The suitable habitats for the Chinese gorals were mainly located in the central and western parts of the Qinling Mountains, while the marginal habitats were in the surrounding areas of the suitable habitats. The mean diurnal temperature range, elevation and annual precipitation were the three environmental variables with the highest contribution rates, which were 41.2%, 38.5% and 14.1% respectively, while the cumulative contribution rate is 93.8%, indicating that they were the main environmental variables affecting the suitability of the goral′s habitats in the Qinling Mountains. The Jackknife test indicated that elevation and mean diurnal temperature range were the dominant environmental factors affecting habitat suitability, whereas the human disturbances had less effects on it. The Chinese gorals preferred to choose living at high elevation regions(1800-3000 m) in that the annual precipitation is about 750—850 mm and the average diurnal temperature is about 8 ℃. The results provide baseline information for future biodiversity conservation planning and landscape management in the Qinling Mountains. The suitable habitat area of gorals in the southwest of Qinling Mountains is seriously fragmented and strongly disturbed by human activities. Therefore, it is necessary to strengthen the systematic monitoring of wildlife and human activities, and establish wildlife corridors in this area to improve the habitat connectivity for Chinese gorals and other species at-risk, so as to promote the long-term survival of wildlife in the Qinling Mountains.