Quantitative analysis of the responses of boundary shifts in farming –pastoral ecotone of northern China to climate change

Climate change can affect the shifts of farming-pastoral ecotone (FPE) boundaries, but previous studies have not adequately detected the climate contributions to the FPE boundary shifts. In this study, we presented gravity center analysis, boundary shifts detected in the X- and Y-coordinate direction and the direction of transects along the boundary, and spatial analysis to detect climate contributions at a 1-km scale in different ecological functional regions from the 1970s to the 2000s.Climate and land use data were used in this study. The results showed that during the 1970s–1980s and 1990s–2000s, the northeastern and southeastern parts of the FPE in northern China had similar spatial patterns with more extensive boundary shifts. In the directions of X-, Y-coordinate and the transects along boundaries, different ecological functional regions had significant differences in climate contributions to FPE boundary shifts during the three periods. In addition, during most of the periods, the results in different directions had good agreement in most of the ecological functional regions. However, the values of contributions in the directions of transects in the X- and Y-coordinate directions (4–56%) were always larger than those in the direction of transects along boundaries (1–17%), which shows that the results in the transect directions are more reliable and stable. Thus, the method of detecting the shifts in the transect directions developed by this study is an alternative one for analyzing the climate contributions to boundary shifts. Further evidences for explanation of the driving forces of climate change were given by spatial analysis of the relationship between climate change and land use change in the context of the FPE boundary shifts in northern China. Our findings provide an improved understanding of the responses of boundary shifts in farming–pastoral ecotone of northern China to climate change, which will be important for addressing adaptation and mitigation measures to climate change and regional land use management.