Modelling the potential distribution and shifts of three varieties of Stipa tianschanica in the eastern Eurasian Steppe under multiple climate change scenarios

The issue of climatic change and its strong influence on species distributions is currently of great interest in the field of biogeography. In this study, three varieties of Stipa tianschanica (S. tianschanica var. tianschanica, S. tianschanica var. gobica and S. tianschanica var. klemenzii), which are high-quality forage for local rangeland, were selected from the desert steppe of the Mongolian Plateau and Central Asia. Based on high-resolution environmental data for past, current and future climate scenarios, we modelled the suitable habitat in 6 periods for S. tianschanica var. tianschanica, S. tianschanica var. gobica and S. tianschanica var. klemenzii using MaxEnt and GIS technology; evaluated the importance of environmental factors in shaping their distribution; and identified distribution shifts under different climate change scenarios. Our results showed that temperature seasonality (bio04) and precipitation in October and November (pre10, pre11) were the most critical factors shaping the distribution of S. tianschanica var. tianschanica, while precipitation in June, August and December (pre06, pre08 and pre12) were the most critical for shaping the distributions of S. tianschanica var. gobica and S. tianschanica var. klemenzii. The suitable future habitat for the three species tended to increase under the RCP2.6 scenario and to decrease to varying degrees in the desert steppe in the RCP8.5 scenario in 2070 as global warming intensified. Overall, the size of the core distribution area and direction of the core distributional shifts are different for each species over the 6 periods. Our prediction showed that although these three varieties belong to the same species, their survival strategy and adaptability are different when faced with the same climate change scenarios. The projected spatial and temporal patterns of the distribution range shifts for S. tianschanica var. tianschanica, S. tianschanica var. gobica and S. tianschanica var. klemenzii will be useful references in developing desert steppe management and conservation strategies for these three ecologically important varieties. (C) 2018 The Authors. Published by Elsevier B.V.