| Net primary productivity (NPP) is the basis for studying the flow of material and energy in the ecosystem. The spatial distribution of NPP is closely related to regional vegetation growth, terrain, climate and other factors, and its changes can reflect the ecological environment quality of a region. The karst faulted basin is a type of mountain basin formed by Cenozoic fault activity and dissolution. Due to its complex terrain, large climate contrast and poor land anti-interference capability, rock desertification is extremely serious and difficult to control. The fault-depression basins are mainly distributed in eastern Yunnan, Xichang, Panzhihua and western Guizhou. After comprehensive management of ecological environment construction represented by rocky desertification management and steep slope ecological management in recent years, the construction of ecological civilization has achieved remarkable results. In order to further explore the response of NPP to changes in the ecological environment, the authors studied the spatial and temporal changes of NPP in Yunnan Fault-depression Basins in 2005, 2010, 2015 and 2019 using the Modis image, the CASA model and GIS. The results are as follows: On the time scale, from 2005 to 2019, the NPP level in Yunnan Fault-depression Basins was declined first, then increased and then decreased again. From a spatial point of view, the average value of NPP decreases from east to west and from south to north. The NPP averages in the eastern and southern regions such as Shizong County, Qiubei County, and Maguan County are higher, while the NPP averages in the west and northern Kunming Xishan District, Kunming Panlong District, Chengjiang County and Chenggong County are lower, with big differences existent between different regions. In addition, in the view of the rocky desertification control, the NPP change is also greater in areas where the area of rocky desertification changes significantly, and the average NPP is significantly increased in areas where the rate of change in rocky desertification decreases significantly. The dynamic changes of NPP indicate that the vegetation in the fault-depression basin in Yunnan Province has been recovered greatly and the rock desertification control project has achieved certain results in recent years; nevertheless, it is still not stable enough, and hence ecological governance will still be a long-term project. |