Spatio-temporal dynamics of land use transitions associated with human activities over Eurasian Steppe: Evidence from improved residual analysis

Abstract

We presented a framework to evaluate the land use transformations over the Eurasian Steppe (EUS) driven by human activities from 2000 to 2020. Framework involves three main components: (1) evaluate the spatial-temporal dynamics of land use transitions by utilizing the land change modeler (LCM) and remote sensing data; (2) quantifying the individual contributions of climate change and human activities using improved residual trend analysis (IRTA) and pixel-based partial correlation coefficient (PCC); and (3) quantifying the contributions of land use transitions to Leaf Area Index Intensity (LAII) by using the linear regression. Research findings indicate an increase in cropland (+1.17 % = 104,217 km²) over EUS, while a - 0.80 % reduction over Uzbekistan and - 0.16 % over Tajikistan. From 2000 to 2020 a slight increase in grassland was observed over the EUS region by 0.05 %. The detailed findings confirm an increase (0.24 % = 21,248.62 km²) of grassland over the 1st half (2000-2010) and a decrease (-0.19 % = -16,490.50 km²) in the 2nd period (2011-2020), with a notable decline over Kazakhstan (-0.54 % = 13,690 km²), Tajikistan (-0.18 % = 1483 km²), and Volgograd (-0.79 % = 4346 km²). Area of surface water bodies has declined with an alarming rate over Kazakhstan (-0.40 % = 10,261 km²) and Uzbekistan (-2.22 % = 8943 km²). Additionally, dominant contributions of human activities to induced LULC transitions were observed over the Chinese region, Mongolia, Uzbekistan, and Volgograd regions, with approximately 87 %, 83 %, 92 %, and 47 %, respectively, causing effective transitions to 12,997 km² of cropland, 24,645 km² of grassland, 16,763 km² of sparse vegetation in China, and 12,731.2 km² to grassland and 15,356.1 km² to sparse vegetation in Mongolia. Kazakhstan had mixed climate-human impact with human-driven transitions of 48,568 km² of bare land to sparse vegetation, 27,741 km² to grassland, and 49,789 km² to cropland on the eastern sides. Southern regions near Uzbekistan had climatic dominancy, and 8472 km² of water bodies turned into bare soil. LAII shows an increasing trend rate of 0.63 year^-1, particularly over human-dominant regions. This study can guide knowledge of oscillations and reduce adverse impacts on ecosystems and their supply services.

Keywords: Human activities; Improved residual trend analysis; Land cover transitions; Linear regression; Pixel based correlation; Remote sensing.