Amphibian and reptilian distribution patterns in the transitional zone between the Euro-Siberian and Central Asia Subrealms

Abstract

There exist some controversies over the larger zoogeographic divisions of the arid areas of Central Asia, whose characteristics include complex ecological environments, complex fauna origins and unique patterns of animal distribution. The aim of this study was to determine, using quantitative analysis, the distribution patterns of amphibians and reptiles in the arid areas of Central Asia, whose various physiographical regions were divided into 17 Operative Geographical Units (OGUs). Based on the presence or absence of 52 amphibian and reptile genera in the 17 OGUs, and by making use of the Czekanowski Similarity Index, the Baroni-Urbani and Buser's Similarity Index, and the strong and weak boundary test, we studied the biotic boundaries within these contested regions. In accordance with our results, the classification dendrogram was divided into two main branches. One branch is composed of the northern OGUs of the Altai Mountains which are a part of the Euro-Siberian Subrealm. The other branch includes all of the OGUs south of the Altai Mountains, which belong to the Central Asia Subrealm. There is a significantly weak biotic boundary (DW>0, GW>GS, P<0.01) between the Euro-Siberian Subrealm and the Central Asia Subrealm that corresponded to the transitional zones. The boundary between the two subrealms runs along the Altai Mountains, the Sayan Mountains, the Hangai Mountains and the Mongolian Dagurr Mountains. The boundaries between the main branches in the Central Asia Subrealm are weak, reflecting the widespread existence of transitional zones in the arid areas of Central Asia. The Tianshan Mountains should be elevated to form its own separate region, "the Middle Asian Mountain Region", which, due to its special fauna and environment, would be classified at the same level as the Mongolia-Xinjiang Region. With the approach of creating a cluster analysis dendogram based upon the genera of amphibians and reptiles, the relationship of these higher level zoogeographical divisions was successfully resolved and the error of long-branch attraction was also avoided. With our clustering dendrogram as the foundation, the independence test was applied to strong and weak boundaries, and this resolved the problem of where to attribute the transition areas and revealed as well the barrier effect that physical, geographic boundaries have upon amphibians and reptiles. The approach of combining genera clustering analysis with a statistical boundary test should be applicable not only to the distribution patterns of other animal groups, but also to delineating large-scale zoogeographical divisions.

Amphibian and Reptilian Chorotypes in the Arid Land of Central Asia and Their Determinants

“…This is a typical example of the variation in species groups found in one region with various climates. An analogous situation also appears between the west and east of the Tianshan Mountains 23 . Several endemic species are distributed in the Turpan Basin because of its isolation from the surrounding desert.…”

“…The climate of the Tianshan Mountains is similar to that of the Euro-Siberian region. However, these regions do not share many of the typical Northern cold-tolerant and hygrophilous species 23 , but have their own endemics (Fig. 4a).…”

“…The environment is complex, having an altitude range of 8998 m, a longitude range of 60°, and a latitude range of 32°. The habitat of amphibians and reptiles in the area are in an extensive transition 23 . Research shows that isolation is the primary cause of the differentiation of reptilian fauna, and the four chorotypes from the geographical fauna analysis of reptiles in eastern China did not refer to the Tibetan Plateau and the arid land of northwest China 24,25 .

Figure 1Location of the research area of amphibians and reptiles in the arid land of Central Asia (the area surrounded by the black line).

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Peer Review #1 of "The adder (Vipera berus) in Southern Altay Mountains: population characteristics, distribution, morphology and phylogenetic position (v0.2)"

“…The range limit of a species is its evolutionary response to the ecological constraints (Holt & Keitt, 2005). Therefore, studying the distribution of the adder in Southern Altay Mountains will help to understand the distribution patterns of reptiles and the influence of climate change on the boundary between the Euro-Siberian Subrealm and the Central Asia Subrealm (Zhang, 1999;Ravkin, Bogomolova & Chesnokova, 2010;Zhou & Shi, 2015). Comparative morphology and molecular phylogeny analyses for adders in Altay could shed light on its adaptation along the gradients of environment and the divergence and colonization history of the genus Vipera.…”

The adder (Vipera berus) in Southern Altay Mountains: population characteristics, distribution, morphology and phylogenetic position

“…The range limit of a species is its evolutionary response to the ecological constraints ( Holt & Keitt, 2005 ). Therefore, studying the distribution of the adder in Southern Altay Mountains will help to understand the distribution patterns of reptiles and the influence of climate change on the boundary between the Euro-Siberian Subrealm and the Central Asia Subrealm ( Zhang, 1999 ; Ravkin, Bogomolova & Chesnokova, 2010 ; Zhou & Shi, 2015 ). Comparative morphology and molecular phylogeny analyses for adders in Altay could shed light on its adaptation along the gradients of environment and the divergence and colonization history of the genus Vipera .…”