Molecular phylogenetic analyses and ecological niche modeling provide new insights into threats to the endangered Crocodile Lizard (Shinisaurus crocodilurus)
Abstract
The endangered crocodile lizard, Shinisaurus crocodilurus, is seriously imperiled by anthropogenic threats, including habitat loss and degradation and most critically over-collection for the international pet trade. As a result, population sizes of crocodile lizards have sharply declined throughout their range, with only a small number remaining in China and a handful of individuals left in Vietnam. To prioritize conservation measures for the species, in this study, we generate new mitochondrial sequences of important new samples and analyze them with existing data. Our results confirm a new genetically distinct population in China, highlighting cryptic genetic diversity within the species. The assessment of climate change impacts on the species suggests that the suitable habitat of one population in China will become severely fragmented, decreased in size, and shifted, while the habitat of two other Chinese populations will remain stable and may even expand given future climate scenarios. In Vietnam, Yen Tu Mountain Range is predicted to serve as a refuge in different climate change projections, but suitable habitat in the border area between Vietnam and China will likely shift geographically. Based on our results, we recommend further field surveys to locate the natural distribution range of the newly identified molecular clade in China and determine the distribution extension of the Vietnamese population in the border area, especially potential occurrence on the Chinese side. Considering the impacts of climate change on the Vietnamese population, designing a corridor to connect the subpopulation’s habitat in the border area with nature reserves in Yen Tu Mountain Range and/or translocating lizards from the site to more suitable habitats might help secure the subpopulation in the context of climate change. In all recommended conservation measures, close collaboration between Vietnam and China will be crucial to effectively protect this potentially shared subpopulation of the highly threatened species.