Mapping and assessment of ecosystem service values using gradient approach: A spatial scenario from Kolkata megacity region, India

Abstract

The transformation of land use and land cover (LULC) profoundly impacts ecosystem service (ES). Urbanization has emerged as a major driver altering landscape patterns and ES dynamics. However, there are very limited studies investigating the spatial interplay between landscape patterns and ES using gradient approach. This study explores the relationship between landscape patterns and ES along the urban-rural gradient (URG) in the Kolkata Megacity Region (KMR), India, from 2000 to 2020. Ten landscape metrics were utilized to elucidate this relationship. Correlation and regression analyses were employed to assess the impact of landscape patterns on ES. Over the last two decades, built-up areas increased by 98 %, while vegetation cover and water bodies decreased by 69 % and 10 %, respectively. Metrics such as number of patches (NP), landscape shape index (LSI), patch density (PD), shape mean (SHP_MN), and division (DIV) showed increasing trends, whereas the largest patch index (LPI), cohesion (COHE), and aggregation index (AI) decreased with distance from the urban core. The total ES value experienced a decline of 66.78 % from 2000 to 2020, with ES values increasing as distance from the urban core increased. Positive correlations were observed between ES values and metrics such as NP, PD, LSI, SHP_MN, DIV, SPLIT, and SHDI, while LPI, COHE, and AI showed negative correlations. Natural landscapes exhibited higher ES values, underscoring the need for integrating spatial landscape planning into decision-making frameworks aimed at enhancing ES.