Multi-Seasonal Analysis of Hydroclimate Variability and Anthropogenic Pressures on the Keta and Muni-Pomadze Wetlands

Abstract

Wetlands regulate hydrological processes, maintain biodiversity, and moderate local climate. However, long-term evidence on hydroclimatic variability and anthropogenic pressure in West African coastal wetlands remains limited. This study assesses rainfall, land surface temperature (LST), and land use/land cover (LULC) change in the Keta Lagoon Complex (KLC) and Muni-Pomadze Ramsar Site (MPRS) from 2000 to 2024. Mann–Kendall tests and Sen’s slope estimators were applied to annual and seasonal rainfall, while Landsat observations were used to evaluate seasonal LST and classify LULC. The indicators were compared across sites and through time to assess their correspondence without attributing causality. Annual rainfall trends were weak and not statistically significant, although minor rainy-season rainfall increased significantly at KLC (p = 0.018). MPRS showed greater thermal variability, with some major rainy season LST values exceeding 44 °C. Built-up cover increased by 9.89 percentage points at KLC and 8.34 percentage points at MPRS, while natural vegetation at MPRS declined from 27.56% to 7.25%. These concurrent patterns indicate stronger landscape modification and lower apparent buffering capacity at MPRS. The findings support site-specific controls on land conversion, restoration of vegetation buffers, improved waste management, and protection of hydrological connectivity. Because the study is comparative rather than causal, the results identify co-variation among indicators but do not quantify the relative contributions of climatic and anthropogenic drivers.