新疆塔什库尔干野生动物自然保护区马可波罗盘羊潜在生态廊道识别

识别野生动物的适宜生境并在适宜生境之间构建生态廊道能够提高生境连通性, 有利于加强种群间基因交流并缓解生境破碎化带来的不利影响。本研究基于生境适宜性评价结果确定了塔什库尔干野生动物自然保护区内马可波罗盘羊(Ovis polii)的核心生境斑块, 运用廊道设计模型Linkage Mapper识别最低成本廊道并确定其优先级。结果表明, 马可波罗盘羊适宜生境主要分布在保护区西北部, 核心生境斑块少且破碎化明显, 夏冬两季核心生境斑块均为28个, 潜在生态廊道分别为45和47条。采用成本加权距离与欧几里得距离之比(CWD : EucD)以及成本加权距离与最低成本路径长度之比(CWD : LCP)两种度量方法评估了生态廊道的质量与重要性。以CWD : EucD来衡量, 夏季质量最高的4条廊道分别是皮斯岭至帕日帕克、同库至马尔洋、科克吐鲁克至帕日帕克, 以及哈尔努孜至同库; 冬季质量最高的3条廊道分别是其克尔克尔至亚希洛夫、萨提曼至依西代尔、其克尔克尔至科克吐鲁克。CWD : LCP分析表明, 夏季质量最高的廊道分别是哈尔努孜至阔克加尔和阔克加尔至马尔洋; 冬季质量最高的廊道分别是爱勒米希至塔萨拉、沙尔比列西南至依西代尔。利用流中心性评估各核心生境斑块和廊道的重要性表明, 帕日帕克、塔萨拉和马尔洋这三个斑块在促进马可波罗盘羊迁移扩散方面的贡献值最高。夏季皮斯岭至帕日帕克、同库至马尔洋和马拉特至其克尔克尔这3条廊道的贡献值最高; 冬季爱勒米希至塔萨拉、沙尔比列至沙尔比列西南和铁尔布尔列至沙尔比列这3条廊道的贡献值最高, 上述核心生境斑块和生态廊道在维持保护区马可波罗盘羊种群迁徙扩散中发挥着关键作用。此外, 赞坎、沙尔比列等斑块虽然面积小、贡献值低, 但起到了维持景观中重要斑块连通的踏脚石作用, 其重要性也不可忽略。研究结果可为塔什库尔干野生动物保护区马可波罗盘羊有效保护、保护区功能区划优化以及当地基础建设项目的规划选址提供科学指导。

Identification of potential ecological corridors for Marco Polo sheep in Taxkorgan Wildlife Nature Reserve,Xinjiang, China

Identifying suitable habitats for wildlife and building corridors between those habitats increases the connectivity of suitable habitat patches, enhancing gene communication, and mitigating the adverse effects of habitat fragmentation. In this study, the core distribution areas of Marco Polo sheep (Ovis polii) were determined based on a suitability index model. The lowest cost corridors were then identified using the Linkage Mapper model and their priorities were determined. Results showed that the suitable habitats of Marco Polo sheep were mainly distributed in the northwestern areas of the Taxkorgan Wildlife Nature Reserve. A total of 28 core patches (CPs) (core patches were defined as habitat patches with an area of larger than 10 km ² in summer and 5 km ² in winter) were confirmed both in summer and winter, which is a lower number and demonstrates fragmentation of suitable habitat. In total, 45 and 47 potential corridors for Marco Polo sheep habitat were identified for summer and winter habitats, respectively. The ratio of the cost-weighted distance and the Euclidean distance ratio (CWD : EucD), and ratio of cost-weighted distance and the least-cost path length (CWD : LCP) were used to evaluate the quality and importance of each corridor. Using the CWD : EucD, the top four highest quality corridors in summer were Tongku to Maeryang, Keketuluke to Paripake, Pisiling to Paripake and Haernuzi to Tongku; the top three highest quality corridors in winter were Qikeerkeer to Yaxiluofu, Satiman to Yixidaier and Qikeerkeer to Keketuluke. In comparison, using the CWD : LCP, the only two highest quality corridors were identified in summer and winter, i.e. Haernuzi to Kuokejiaer and Kuokejiaer to Maeryang in summer and Ailemixi to Tasala, the southwest of Shaerbilie to Yixidaier in winter. Current flow centrality was used to evaluate the contribution of each core patch and corridor to facilitate sheep movement. The highest contributions were from patches in Paripake, Tasala and Maeryang in summer and patches Paripake, Tasala and Maeryang in winter. The highest corridors were between patches Tongku to Maeryang, Malate to Qikeerkeer and Pisiling to Paripake in summer, and Ailemixi to Tasala, Shaerbilie to the southwest of Shaerbilie and Tieerbuerlie to Shaerbilie in winter. These results suggest that the above-mentioned CPs and corridors play key roles in maintaining connectivity of Marco Polo sheep habitats. Patches such as Zancan and Shaerbilie that are small in area and contribution little, still play an important role in maintaining the connectivity of important patches in the landscape. The results of present study will optimize understanding of functional zones and improve management schemes for conservation of this endangered species in the Taxkorgan Nature Reserve.