Oral Presentation- Symposium 12th International Mammalogical Congress

Wild rats are evidence of environmental changes in Asia through the late Quaternary (#85)

Deyan Ge 1 , Liang Lu 2 , Zhixin Wen 1 , Jilong Cheng 1 , Lin Xia 1 , Qisen Yang 1
  1. Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Chaoyang District, Beijing, China
  2. State Key Laboratory for Infectious Diseases Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China

In our recent study, we sought to explore the biogeographic history of the wild rats in Asia and to understand the long-term persistence of high species diversity in this region. The rat genus Niviventer is one of the dominant taxa in the local mammal communities from southeast Asia to central China. The N. andersoni species complex (NASC) is highly adapted to middle to high elevations. In contrast to previous studies that have proposed regional refuges in the eastern or southern Hengduan Montains (HDM) and emphasized the influence of climatic oscillations on local vertebrates, we found that the HDM as a whole acted as refuge for the NASC and that the historical range shifts of NASC mainly occurred in the marginal regions. Demographic analyses revealed slight recent population declines in Yunnan and south-eastern Tibet, whereas the populations of Sichuan and of the entire NASC were stable. This pattern differs greatly from classic paradigms of temperate or alpine and holarctic species. On the contrary, N. confucianus is a dominant rat species with a wide elevational range in natural forests from southern to central and north of China. Inferring the demographic dynamics of this species uncovered dramatic population expansion in southwest, central and northern China that occurred since 0.5 Mya in the Late Pleistocene, but only slight expansion in Yunnan/Tibet. Environmental changes since the Late Pleistocene, particularly the decrease of predation and competition from the loss of megafanua, together with seed hoarding behavior, probably contributed to the dramatic population boom of this species.