基于GIS和MaxEnt技术对濒危物种褐马鸡的保护空缺分析

Reserve gap analysis of endangered brown eared pheasant(Crossoptilon mantchuricum) through GIS and MaxEnt technology

自然保护区网络的设计对濒危物种及其生境的保护至关重要。地理信息系统(GIS)和MaxEnt模型作为一种有效而可靠的工具已广泛应用在野生动物的管理和自然保护区设计中。褐马鸡是中国特有的濒危雉类,当前存在3个分隔的地理种群。由当前已知分布点,采用最小凸多边形法(MCP)分别划定3个分布区,并设计分布区外20km的缓冲距离为研究区域。在研究区内,针对褐马鸡及其生境的保护已建立8个国家级和8个省级自然保护区网络。根据褐马鸡栖息地特征选择11个生境因子为预测背景,基于45个当前分布点利用MaxEnt模型预测褐马鸡当前的潜在适宜生境。由MaxEnt模型检验可知,训练集和测试集的平均遗漏率(OR)分别<0.10和<0.35。训练集和测试集的AUC均值分别为0.957 5和0.898 5,AUC标准偏差为0.040 6,模型预测精确度较高。在GIS10.0软件中,由所选的10%TPLT阈值(0.30)将预测概率图转化为Presence/Absence二值图,并分析当前自然保护区对适宜生境的保护状况。研究发现当前自然保护区存在一定的保护空缺,有18 896 km2适宜生境未受保护;省级自然保护区在适宜生境保护中起到关键的连接作用,在保持褐马鸡适宜生境的完整性和连通性中不可或缺。建议相关保护部门明确省级自然保护区的边界,制定可供GIS分析的省级自然保护区的数字图层,为今后自然保护区网络的规划和设计提供技术支撑。

The nature reserve design and networks are all important for wildlife and habitat conservation.Geographical information system（ GIS） and MaxEnt model are efficient and most reliable tool in setting habitat conservation priorities for nature specially endangered species. Brown eared pheasant is an endangered mountain pheasant endemic in China. Presently,the brown eared pheasant has three isolated populations,which were the western population in Shaanxi Province,the central population in Shanxi Province,and the eastern population in Hebei Province and Beijing. The current distribution area of three populations of brown eared pheasant were delimited by the minimum convex polygon method（ MCP） base on current distribution points,and set the 20 km buffer distance outside the distribution region as the study area. Eight national nature reserves and eight provincial nature reserves were instituted for protecting brown eared pheasant and its habitat in the study area. MaxEnt model was used to obtain the current potential suitable habitat base on 11 environmental variables and 45 current distributing sites. All of the training OR was 〈0. 10,and all of the test OR was 〈0. 35. The AUC results revealed a training average AUC of 0. 957 5,test average AUC of 0. 898 5,and AUC standard deviation of0. 040 6,indicative of good model prediction performance. 10 thpercentile training presence logistic threshold（ 0. 30） was used to divide the Presence / Absence map. Then we analyzed the protection condition of reserves for suitable habitat in the GIS10. 0 software. The suitable habitat of 18 896 km2 located outside the reserves,which should be considered for protection. The provincial nature reserves play the crucial link roles,and to keep the integrity and continuity of the suitable habitat for brown eared pheasant is important. Local conservation departments should confirm reserve boundary and set GIS analysis layer of provincial nature reserves for reserves network planning and design to provide technical support in the future.