Effects of Land Cover Changes on Ecosystem Services in the Kulpawn Catchment of the White Volta River Basin of Ghana.

Abstract

The Kulpawn River Basin has experienced a significant decline in vegetation cover due to land use and land cover changes between 1995 - 2023, affecting hydrological flows and ecosystem services. This study evaluated the ecosystem service values (ESV) associated with these changes. Random Forest (RF) algorithm in R was applied to extract LULC information from Landsat images from 1995-2023. The Benefit-Transfer Model (BTM) was employed to estimate the ESV over the study period. Results showed that dense savannah vegetation and water bodies had been converted into Built-up areas (15.17%), Agricultural land (14.14%), and light savannah vegetation (8.73%) leading to the reduction in the area's dense savannah vegetation and water body by 25.71% and 20.10% respectively. The total estimated values of ecosystem services were; US$ 410,09 ×108, US$ 362.92 ×108, US$ 335×108, and US$ 319.28 ×108 for 1995, 2005, 2015, and 2023 respectively. The total ESV declined from US$ 410.09×10⁸ (20.51%) in 1995 to US$ 319.28×10⁸ (15.96%) in 2023, signifying the effect of LULC changes on the catchment ecosystem services. The results showed strong correlations between LULC characteristics and catchment ESV. The results further revealed that 1% LULC changes resulted in corresponding ESV changes of 0.99, 1.07, 0.82, and 0.78 across 1995 2005, 2005–2015, and 2015–2023. Among the ecosystem functions, provisioning services were the most affected (US$ -31.71×10⁸), followed by cultural (US$-28.93×10⁸), regulating (US$-20.87×10⁸), and supporting services (-11.60×10⁸). The findings highlight the vulnerability of ecosystem services to LULC changes. Hence, there is a need to provide a framework for developing strategies to mitigate LULC conversions and degradation.