Spatially explicit gridded modeling of the dynamics of ecosystem services and land use carbon emissions in the Poyang Lake Urban Agglomeration

Rapid land-use change in the Poyang Lake Urban Agglomeration is reshaping both ecosystem service supply and regional carbon pressure. This study integrated InVEST-based estimates of carbon storage, water yield, soil conservation, and habitat quality with an anthropogenic-inventory carbon accounting framework for 2000, 2005, 2010, 2015, and 2020. Direct land-use carbon balance was estimated for cropland, woodland, grassland, waterbody, and unused land, while the residual statistical inventory was treated as an anthropogenic emissions inventory rather than being assigned wholly to built-up land. That inventory was spatially allocated to grids by combining built-up land share with normalized population and GDP proxies. Integrated ecosystem service value (IESV) was derived from the percentile-truncated min-max normalization of the four services, and the carbon pressure-IESV relationship was examined at 3 km, 5 km, and 10 km scales using Pearson correlation and bivariate Moran’s I. Across the region, the anthropogenic inventory rose from 12.08 Mt in 2000 to 47.29 Mt in 2020, whereas the direct land-use component remained a net sink of about 1.86–2.04 Mt. At the retained 5 km scale, the carbon pressure-IESV trade-off was very weak in 2000–2010 (Pearson r = −0.081 to −0.145) but strengthened markedly by 2015–2020 (r = −0.413 and −0.415); bivariate Moran’s I remained negative throughout (−0.072 to −0.347, p < 0.01). The multi-scale comparison showed that 5 km preserved the strongest average spatial autocorrelation signal while avoiding the over-fragmentation observed at 3 km and the smoothing introduced at 10 km. High carbon-pressure/low-IESV clusters expanded around Nanchang and the main urban corridors, whereas low carbon-pressure/high-IESV clusters remained concentrated in forest- and wetland-dominated margins. These results provide a more defensible basis for coupling anthropogenic emissions and ecosystem services in lake-urban landscapes and support differentiated carbon mitigation and ecological restoration strategies in the Poyang Lake Urban Agglomeration.