  The karst area in Yunnan-Guangxi-Guizhou region in southwest China is known
for widespread rocky desertification but several studies report a greening
trend since the year 2000. While the start of the greening trend seems to match
with the implementation of ecological conservation projects, no statistical
evidence on a relationship between vegetation greening and eco-engineering
exists. Moreover, dominant factors influencing the spatial patterns of
vegetation trends have rarely been investigated. Here we use six comprehensive
factors representing the natural conditions and human activities of the study
area, and several statistical models consistently show that eco-engineering
explains large parts of the positive vegetation trends in the karst areas,
while negative vegetation trends in non-karst areas of Yunnan were related with
a decrease in rainfall. We further show that the interaction of eco-engineering
with other factors leads to a heterogeneous pattern of different vegetation
trends. Knowing and understanding these patterns is crucial when planning
ecological restoration, especially in diverse landscapes like China karst and
the methods can be reused in other restoration areas.
