Rapidly declining wetland ecosystem service value indicated by land use/land cover changes in the Elephant Marsh, Malawi

Abstract

Studies on the impact of land use/land cover changes on ecosystem service value (LULCC-ESV) have remained sparse or highly concentrated in specific regions, i.e., Asia, Europe, and North America. In Africa and Latin America, particularly in Ramsar-designated sites, such studies remain historically scarce despite increased exposure of these sites to human activities. This paper applied multi-temporal, high-resolution, and statistical approaches to evaluate i) the spatial-temporal scales of Elephant Marsh LULCC-ESV and ii) the drivers of ESV changes. The main goal is to generate much-needed evidence for real-time decision-making and the enactment of “wise use” principles. The principal findings indicate losses of forest, marshes, shrubland, and area covered by water at annual rates of 205.53 ha, 592.13 ha, 187.66 ha, and 23.43 ha, respectively, during 1998–2022. These land cover types were converted into barren (64.04 ha/yr), cultivated (894.4 ha/yr), and settlement (43 ha/yr). Marshes had the highest ESV in 1998, i.e., US$4.28 billion. However, their ESV declined at an annual rate of 0.87% (declining to US$2.28 billion by 2022). Water, forest, and shrubland experienced annual ESV losses of 0.25%, 1.27%, and 0.94%, respectively. Cultivated and settlement areas gained annual ESV at rates of 0.73% and 0.28%, respectively. Overall, the annual rate of ESV loss due to LULCC was estimated at 0.73% (declining from US$4.40 billion to US$2.54 billion during 1998–2022). Significant (P < 0.01, 0.05, and 0.1) cold and hot spot ESV clusters were observed at several notable sites in the wetland, although some areas also showed no significant (P > 0.01, 0.05, and 0.1) cold or hot spots. Several key factors, including population growth, livestock production, agricultural production, extreme weather events, policy conflicts, and irrigation expansion, significantly contributed to the ESV loss (P < 0.01 or 0.05). From a Ramsar Convention perspective, our findings offer valuable insights into actionable ecological restoration and management of designated arid and semi-arid Sub-Saharan wetlands.