Abstract: Under the context of ecological protection and high-quality development of the Yellow River basin, we assessed the relationship between regional development and ecological environment quality in the Xiaoqing River basin, with Landsat images from 2009, 2015, and 2021 as the main data source. Coupled with four indicators (greenness, wetness, dryness, and heat), the remote sensing-based ecological index (RSEI) was obtained using principal component analysis, and the spatial and temporal variations of ecological environment in the study area were analyzed. On the basis of RSEI, the point of interest (POI) data of social attributes were introduced to construct the modified RSEI (MRSEI), which was compared with the RSEI for analysis. The results showed that the RSEI of the region showed a general trend of decreasing and then increasing, with mean values of 0.51, 0.41, and 0.60 in 2009, 2015, and 2021, respectively. The area of improved land was 3842.69 km², accounting for 44.70% of the total area. The improvement area was mainly in the central and northern parts. The change of semi-ecological land was the most obvious, with 16.70% of land converted to ecological land and 14.38% of land converted to non-ecological land. Compared with RSEI, MRSEI was closer to the ecological index value, and could more accurately describe the relationship between ecological environment changes and human activities in this region, with better regional applicability.

Key words: ecological land, remote sensing-based ecological index, temporal and spatial variations, ecological quality, POI data