随着经济社会的发展和全球气候变化，野生动物及其生存环境越发受到外界干扰。青藏高原作为全球气候变化的敏感地区，在近几十年来道路建设等人类活动不断增强，有蹄类物种的适宜栖息地和生态廊道的分布也因此受到影响。对于适宜栖息地变化的分析和生态廊道的识别对有效保护青藏高原有蹄类物种具有重要的现实意义。

本研究以青藏高原有蹄类动物为研究目标物种，收集并处理了过去时期（1960-1990年）和当前时期（2000-2015年）的环境因子数据，利用MaxEnt模型确定了青藏高原19种有蹄类动物适宜栖息地的分布格局，并比较了不同时期它们的栖息地分布和物种丰富度的变化。然后基于物种栖息地适宜性结果，利用电路理论模型构建了有蹄类物种的生态网络并分析其变化。最后，Zonation模型被用于识别有蹄类动物栖息地和生态廊道的优先保护区域。主要结论如下：

（1）结果表明，MaxEnt模型可以很好地预测青藏高原有蹄类动物的分布。在当前时期，超过一半的有蹄类物种主要分布在青藏高原的东南部。而藏羚羊、藏野驴和野牦牛这三种关键有蹄类物种主要分布在高原中西部地区。由于气候变化影响和人类活动干扰等，青藏高原有蹄类物种的栖息地在过去的几十年中发生了显著的变化。且高原东南部和西北部有蹄类动物的栖息地变化截然相反。在过去的几十年中，原本位于高原西北部的栖息地已经大面积丧失。而最初位于高原东南部的有蹄类动物已经向原栖息地的西北方向扩展。距湖泊的距离以及降水是影响大多数有蹄类物种分布的主要环境因素。

（2）生态网络研究结果表明，部分有蹄类物种的生态廊道分布格局与其栖息地分布格局相似，即主要分布在青藏高原的东南部，例如马麝、林麝、羚牛等有蹄类物种。只有藏羚羊、藏原羚、藏野驴和野牦牛的廊道主要分布在青藏高原的中西部地区。大部分有蹄类物种的生态廊道在近几十年里发生了较为明显的变化。原廊道位于青藏高原东南部的有蹄类物种，主要向西北方向扩展其新增廊道。藏原羚、藏野驴和野牦牛的新增廊道主要位于高原中部地区，而丧失的生态廊道则主要位于原廊道的北部和南部地区。而藏羚羊的廊道变化则恰恰相反。就单物种廊道面积变化而言，马麝、林麝、马鹿、水鹿、毛冠鹿以及白唇鹿的廊道面积增加了50％以上。而岩羊、小麂以及鹅喉羚的廊道面积则减少了三分之一以上。此外，青藏高原的东南和西南部越来越多的地区可以被6种以上有蹄类物种用作生态廊道，这主要与高原东南部地区降水的显著增加有关。

（3）Zonation模型确定的栖息地重点保护地区主要位于青藏高原的东南部。现有的自然保护区可以基本有效地保护藏羚羊、藏野驴以及野牦牛的适宜栖息地。且青藏高原的中部地区仅分布有藏羚羊、藏野驴和野牦牛三种关键有蹄类的生态廊道。目前有17个自然保护区在不同程度地保护着这三种有蹄类的生态廊道，可以有效地保护这三个物种近一半面积的关键生态廊道。其中羌塘自然保护区的保护至关重要。然而部分廊道主要分布在自然保护区的实验区和缓冲区，保护力度不足。因此，自然保护区布局优化等相关保护仍需进一步加强。

本研究可为协调发展与保护之间的矛盾，促进青藏高原的生物多样性保护提供重要的科学依据。研究结果对优化青藏高原现有自然保护区布局以及国家公园的建设具有重要意义，也可为适宜栖息地变化的分析和生态廊道的确定提供方法学参考。

With the global climate change and development of economy and society, the wild animals and their living environment are increasingly disturbed by the climate and human beings. The Qinghai-Tibet Plateau is a sensitive area of global climate change, human activities such as road construction have continued to increase in recent decades. Therefore, the suitable habitats and ecological corridors of ungulate species have been affected to varying degrees. The analysis of suitable habitat changes and the identification of ecological corridors have important practical significance for the effective protection of ungulate species on the Qinghai-Tibet Plateau.

In this study, we took the ungulate species on the Qinghai-Tibet Plateau as the research species, collected and processed environmental data of the past period (1960-1990) and the current period (2000-2015). Then we used the MaxEnt model to determine the distribution patterns of 19 ungulate species on the Qinghai-Tibet Plateau, and the changes in their habitat distribution and species richness in different periods were compared. Then, the circuit theory model was used to construct the ecological network of ungulate species based on the habitat suitability of the species. Finally, the Zonation model is used to identify important regions for ungulate species. The main conclusions are as follows:

(1) The results show that the MaxEnt model has a good effect on the distribution prediction of ungulate species. In the current period, more than half of the ungulate species are mainly distributed in the southeastern plateau. Tibetan antelope, Tibetan wild ass and wild yak, which are endemic to the Qinghai-Tibet Plateau, are mainly distributed in the central and western regions. In the past few decades, the habitats of ungulates species have changes significantly due to the climate change and human activities. The habitats of ungulates in the southeast and northwest of the plateau change completely in opposite directions. The habitat that was originally located in the northwest of the plateau has been largely lost. The ungulates originally distributed in the southeastern part of the plateau have expanded to the northwest of their original habitat. The distance from the lake and precipitation are the main factors affecting the distribution of most ungulate species.

(2) Ecological network results show that the distribution pattern of ecological corridors for some ungulate species is similar to the distribution pattern of their habitats. They are mainly distributed in the southeast of the Qinghai-Tibet Plateau, such as Alpine Musk Deer, Forest Musk Deer and Takin. Only the corridors of Tibetan antelope, Tibetan gazelle, Tibetan wild ass and wild yak are mainly distributed in the central and western regions of the Qinghai-Tibet Plateau. Significant changes have happened on the ecological corridors of most ungulate species. The new corridors for ungulate species whose original corridors are located in the southeast of the Qinghai-Tibet Plateau mainly extend northwest. The new corridors for Tibetan gazelle, Tibetan wild ass and wild yaks are mainly located in the central plateau, while the lost ecological corridors are mainly located in the northern and southern areas of the original corridors. The changes in the corridors of Tibetan antelopes are just the opposite. In terms of the changes in the corridor area of single species, the corridor area of alpine musk deer, forest musk deer, red deer, sambar, tufted deer and white-lipped deer increased by more than 50%. While the corridor area for blue sheep, chinses muntjac and goitered gazelle has been reduced by more than one third. In addition, more and more areas in the southeast and southwest of the Qinghai-Tibet Plateau can be used as ecological corridors by more than 6 ungulate species, which is mainly related to the significant increase in precipitation of these regions.

(3) The important suitable habitats identified by Zonation model are mainly located in the southeast of the Qinghai-Tibet Plateau. The existing nature reserves can basically effectively protect suitable habitats for Tibetan antelopes, Tibetan wild ass and wild yaks. Moreover, in the central part of the Qinghai-Tibet Plateau, there are only ecological corridors of three national first-class protected animals: Tibetan antelope, Tibetan wild ass and wild yak. There are currently 17 nature reserves protecting these ecological corridors of three ungulate species to varying degrees, and can effectively protect nearly half of the key corridors for these three species. Among them, the protection of the Qiangtang Nature Reserve is extremely important. However, part of the corridors are mainly distributed in the experimental areas and buffer zones of nature reserves. Therefore, related protections such as the optimization of the layout of nature reserves still need to be further strengthened.

This research can provide an important scientific basis for coordinating the contradiction between development and protection and promoting the biodiversity protection on the Qinghai-Tibet Plateau. The research results are of great significance for improving the construction and optimization of nature reserves, and can provide a methodological reference for the analysis of habitat changes and the determination of ecological corridors.