Wetland ecosystem dynamics and ecosystem service value implications in the Lake Tana Biosphere Reserve: a spatio-temporal analysis

Abstract

Wetlands provide essential ecosystem services worldwide. Although wetlands occupy a small proportion of Ethiopia's land area, ecosystems such as the Lake Tana Biosphere Reserve (LTBR) support rich biodiversity. Despite their ecological importance, these wetlands are increasingly degraded by anthropogenic and natural factors. However, limited research has examined the spatio-temporal dynamics of wetlands and their effects on ecosystem service values (ESVs) in LTBR. This study was therefore aimed to analyze wetland dynamics and their implications for ESVs using the Random Forest (RF) algorithm and the benefit transfer (BT) method. In this study, Landsat imagery at 10-year intervals from 1994 to 2024 was acquired for the analysis. The images were classified in Google Earth Engine using six land cover classes: water body, wetland, cultivated land, forest, built-up area, and grazing land. Accordingly, the results showed that wetland area declined from 102.81 km² in 1994 to 40.06 km² in 2024, mainly due to conversion into cultivated land (9,317.8 ha) and grazing land (904.3 ha). This caused the reduction of wetland ESVs by 61.03% over the study period, indicating substantial ecosystem degradation. Thus, these findings highlight the urgent need for coordinated conservation and restoration measures to protect and sustain LTBR wetlands.