中国科学院昆明动物研究所机构知识库

遗传多样性是评估一个物种是否受潜在威胁的标准，是当今生物多样性保护工作中关注的重点。影响物种遗传多样性大小的因素众多：从群体自身角度来看，群体遗传多样性大小与种群动态及分布范围有着紧密的联系。物种遗传多样性的维持是一个动态平衡的过程，群体迁移、扩张收缩和世代遗传主要决定着遗传多样性现在的空间分布格局和未来发展命运。此外，气候环境变化作为一个重要的外界因素，主要通过作用于群体动态而对物种遗传多样性造成影响。气候条件决定着栖息地适合度的大小，物种在分布范围和种群大小上对气候变化做出响应，并最终形成种群遗传多样性格局。 青藏高原有着独特的气候和生态特征，是研究气候因子和物种多样性动态之间关系的理想区域。该区域气候系统有着超前性和敏感性的特征，且生态环境脆弱，受全球气候变化的影响较大。青藏高原上的两栖爬行动物组成一个相对独立的区系，也面临着不同程度的多样性损失问题。所以有必要掌握整个区域内此类群的多样性格局及其变化趋势，作为青藏高原生态和物种保护的理论基础。此次研究选取青藏高原面上不同区域广泛分布的 12 种两栖爬行动物为研究对象， 通过群体遗传多样性分析、群体历史动态重建、物种分布模型及遗传多样性预估分析来推断区域内气候因子的变动对研究类群多样性变化趋势产生何种影响，及其遗传多样性受威胁程度。 所得结果显示， 青藏高原两栖爬行动物遗传多样性分布格局表现为， 单倍型多样性高的区域位于青藏高原南部的东南缘和东部的东北缘，而核苷酸多样性高的区域集中在羌塘高原和横断山脉地区。各物种种群历史动态表现出异步性，东北部的两种沙蜥和雅鲁藏布江中游河谷地区分布的几个物种都发生了种群的收缩事件，而其他物种则经历了近期的种群扩张。经历冰期后扩张的两栖爬行动物在末次冰期的适合生境都位于高原边缘地带的河谷地区，说明历史上高原边缘的低海拔地区为它们提供了冰期的避难所。 同时， 我们预测到未来气候变化下 12 种两栖爬行动物分布范围面积变化趋势存在区域差异性。青藏高原南部和中部的物种分布范围都会发生扩张，而东北 部和东部物种的分布范围面积都会缩小或者变化幅度不明显。未来分布范围发生收缩的物种中，遗传多样性受气候变化威胁最大的是青藏高原东北部的两种沙蜥，该区域也是青藏高原上两栖爬行动物存在灭绝风险的重点区域。

Genetic diversity is the criterion to assessing whether a species is under potentialthreats, and is the focus of today's biodiversity conservation works. There are manyfactors influencing the genetic diversity of species: from the perspective of populationitself, genetic diversity is closely related to population dynamics and distribution. Themaintenance of species diversity is a process of dynamic equilibrium. Migration,expansion or contraction mainly influence the spatial pattern of today’s geneticdiversity and the future development of the population. In addition, climate change, asan important external factor, mainly affects the genetic diversity of species through thedemographic dynamics. Climatic conditions determine the habitat suitability, thenorganisms respond to climate change with distribution and population size, andeventually form their genetic diversity pattern. The Qinghai-Tibet Plateau has unique climatic and ecological characteristics. It isan ideal area to study the relationship between climate factors and biodiversitydynamics. The climate system in the region is characterized by foresightedness andsensitivity. The ecological environment here is vulnerable, which is susceptible to theinfluence of global climate change. The amphibians and reptiles on the Qinghai-TibetPlateau make up a relatively independent biota, however, is faced with different degreesof loss of diversity. Therefore, it is necessary to know the diversity pattern and its futuretrend in this whole region, as the theoretical basis for the ecological conservation workof the Qinghai-Tibet Plateau. In this study, we selected 12 widely distributed amphibians and reptiles in differentregions of the main Qinghai-Tibet Plateau as the research object. Through the historypopulation genetic diversity analysis, demographic dynamic reconstruction, speciesdistribution modeling and the genetic diversity prediction analysis, we infer howclimate changes affect these species, and its threat degree of their genetic diversity. Results showed the genetic diversity pattern of the amphibians and reptiles on Qinghai-Tibet Plateau. The high haplotype diversity areas locate at the southeasternedge of the southern Qinghai-Tibet Plateau and the eastern northeast edge of easternQinghai-Tibet Plateau, while areas of high nucleotide diversity concentrate inQiangtang Plateau and the Hengduan Mountains region. The demographic historicaldynamics of each species showed asynchrony. Two kinds of lizards in the northeast ofQinghai-Tibet Plateau and species distributed on midstream region of Yarlung ZangboRiver has gone through some contraction events, while other species has experienced arecent population expansion. The amphibians and reptiles with recent expansionsurvived through the Last Glacial Maximum in the relatively suitable area located inthe valley in the edge of plateau. It reveals that the low altitude region of the frontierarea provides them with glacial refugia during the harsh periods. At the same time, we predicted that there would be regional differences in thedistribution changes of 12 amphibians and reptile under the future climate. The speciesin the southern and central Qinghai-Tibet Plateau will expand, while the distribution ofnortheastern and eastern species will contract or not significantly change. Among thespecies with future distribution contractions, two kinds of sand lizards in the northeastQinghai-Tibet Plateau is threatened mostly by the changing climate. And this region isalso a key area with high risk of extinction on the plateau, which should draw moreattention on ecological healthy of it.