Geological and climatic histories likely shaped the origins of terrestrial vertebrates endemic to the Tibetan Plateau

Abstract

Aim The Tibetan Plateau (TP) hosts many endemic species, but questions regarding when and from where these species originated have not been comprehensively answered. Here, we provide a synthesis of the biogeographical history of terrestrial vertebrates endemic to the TP and investigate the potential drivers of their spatio‐temporal origins. Location Tibetan Plateau and its surrounding regions. Time period Cenozoic. Major taxa studied Terrestrial vertebrates. Methods We used dispersal–extinction–cladogenesis models based on time‐calibrated phylogenies to reconstruct the ancestral ranges of 174 endemic TP species and compiled the ancestral ranges and age estimates of their dispersal events. We generated a possibility map of source areas for endemic TP species by counting the incidence of non‐TP sister clades in 110 km × 110 km grid cells. We used generalized linear mixed models to assess the relative importance of historical processes and environmental factors in explaining the geographical variations in the source areas. We created subsets based on four vertebrate classes to test whether the dispersal events varied spatially and temporally among taxonomic groups. Results We found that the endemic species colonized the TP as early as 55 Ma, and that the main colonization phase started to increase around 15 Ma and peaked after 6 Ma. The major source areas of endemic TP species include the Hengduan Mountains, the Himalayas, and Central Asia. Elevation difference had the strongest effect on the source areas, followed by geographical distance. The spatio‐temporal origins of species endemic to the TP and the potential drivers showed significant differences among vertebrate classes. Main conclusions Our study supports the hypothesis that endemic TP species originated from various zoogeographical regions at different times and highlights the important roles of the TP uplift and past climatic changes for determining the spatio‐temporal origins of endemic TP species.

Rapid genetic divergence and mitonuclear discordance in the Taliang knobby newt (<i>Liangshantriton taliangensis,</i> Salamandridae, Caudata) and their driving forces

“…Resistance distance was a main reason for the population genetic structure of L. taliangensis ( Figure 6A ; Supplementary Table S14), suggesting that strong gene flow may have occurred in adjacent regions and regions with high geographic connectivity. The barrier effect of geographic distance is ubiquitous among organisms, especially in amphibians due to their low dispersal ability ( Bani et al, 2015 ; He et al, 2021 ; Waraniak et al, 2019 ). In addition, the effect of temperature difference was weak but significant when environmental dissimilarity was analyzed alone ( Figure 6B ; Supplementary Table S14).…”

“…Salamanders have a particularly high demand for vegetation, not only as terrestrial shelters ( Belasen et al, 2013 ; Otto et al, 2014 ) but also as microenvironments created by the interaction between precipitation and vegetation ( Escoriza & Hassine, 2014 ). The barrier effect on gene flow, imposed by elevational differences, has been demonstrated in many amphibians, and is particularly important for high-altitude and pond-breeding species ( Atlas & Fu, 2019 ; He et al, 2021 ; Sánchez-Montes et al, 2018 ). The north-south running XXL mountains, with a highest peak of 4 791 m a.s.l., may have driven divergence among the East and West genetic clusters of L. taliangensis .…”

“…Topographical changes, such as mountain and river systems caused by orogenesis, are commonly regarded as geographical barriers that promote biodiversity, especially in species with limited dispersal abilities ( Rana et al, 2021 ; Sánchez-Montes et al, 2018 ). Mountainous regions often become hotspots of species diversity and lineage divergence ( Kozak & Wiens, 2010 ; Noroozi et al, 2018 ), with the uplift of the Qinghai-Xizang (Tibet) Plateau (QTP) receiving considerable attention ( He et al, 2021 ). The barrier effect caused by this uplift has been documented for various fauna and flora taxa from the QTP and adjacent areas ( Huang et al, 2017 ; Wang et al, 2017 ; Ye et al, 2019 ).…”

“…Cold-tolerant species or species with distribution areas in climatically stable zones often survived in situ instead of migrating to refugia ( Sánchez-Montes et al, 2019 ; Wang et al, 2017 ). Microrefugia play an important role in the rapid divergence and persistence of lineages in mountainous regions with severe climatic fluctuations ( He et al, 2021 ; Rana et al, 2021 ; Vasconcellos et al, 2019 ). Furthermore, shifts in species range caused by glacial-interglacial cycles provide recurrent opportunities for expansion and admixture of lineages, thus facilitating the occurrence of mitonuclear discordance ( Dufresnes et al, 2020 ; Phuong et al, 2017 ).…”

Joint effects of environmental filtering and dispersal limitation on the species assemblage of the Tibetan Plateau

“…Additionally, uplift-driven changes in climatic conditions during the Cenozoic could have probably promoted the increased rate of species extinction on the Qiangtang Plateau, and its present-day biota was subsequently recolonized and assembled by species adapted to cold conditions (Ding et al, 2021). Contrastingly, the Hengduan Mountains and Himalayas probably served as shelters for the TP species during the Quaternary glacial period (Yu et al, 2019) because these regions show high topographical and temperature variations.…”