Transition of “production-living-ecological”functions of land use in cross-boundary metropolitan regions and its driving factors

This study aims to analyze the evolution, spatiotemporal patterns, and driving factors on the transition of the “production-living–ecological” (PLE) functions of land use in the cross-boundary region. The study area was taken as the overlapping area between the Nanjing and Hefei Metropolitan Area in southern China. The data was then collected from the remote sensing of land use, natural resources, and environment, as well as the socio-economic statistical information over five periods (2000, 2005, 2010, 2015, and 2020). A series of approaches was also employed, such as the entropy weight method, global spatial autocorrelation, and the geographical detector. The results show that there was a relatively low level of regional land-use multifunctionality. The functional index shared an inverted-wave-like (resembling a “~” rotated by 180 degrees) pattern of the “initial decrease, followed by an increase, and then another decrease”. From a temporal perspective, the mean value of the overall land-use multifunctionality increased from 0.183 to 0.211 between 2000 and 2020, indicating an overall upward trend. In spatial distribution, the overall land-use multifunctionality exhibited a spatial pattern of“high in the south and low in the north, while the high in the central urban area and low in the peripheral counties/districts”. Among them, the regional disparities were gradually narrowed in the spatial distribution. There were relatively low differences in the functional index among counties. A developmental trend of the “shifting from diversification to simplification”was also observed in the overall land-use multifunctionality. The ecological functions were dominated to drive the overall development of the region's functions. There was a relatively low level in the production function of regional land use. An evolution trend of the initial growth followed by decline was also found in the production function of land use, where the growth rate first accelerated and then slowed down. The mean value rose from 0.189 to 0.227. The growth was achieved in 80.95% of the counties/districts. There was also the spatial pattern of the “high in the southeast and low in the southwest and north; The average index level was high in the south and low in the north for the living function of land use. While the differences in the living and ecological function indices among counties exhibited a pattern of “narrowing-expanding–narrowing”.The living and ecological function of land use shared a fluctuating upward trend, with the mean value increasing from 0.087 to 0.100, and from 0.364 to 0.292 in 2005 before rebounding to 0.389 in 2020, respectively. The average index level in the ecological function of land use was higher than that in the production and living functions. The diverse patterns were always found in the influencing factors in the production function. The main driving factors were determined as social production and economic development. The total population, urbanization level, and road network density were the dominant influencing factors in the living function. Overall, the findings can also provide a decision-making basis to regulate the transformation of the land-use functions in the cross-boundary regions. Regional ecological and environmental construction can be expected to promote green land use.