Impacts of climate change and human activities on the Walukuba-Masese wetland ecosystem (Lake Victoria basin)

Abstract

Urban wetlands function as critical ecosystems, offering essential services such as water filtration, flood control, and biodiversity conservation to mention a few. However, this type of ecosystem faces immense pressure from both climate and anthropogenic stressors. Numerous studies have documented the effects of these stressors on wetland processes and ecosystem services; however, these studies span a wide range of geographical scales, and the findings may not be directly applicable at local scales. The aim of this study, therefore, was to examine the socio-ecological dynamics of the Walukuba Masese wetland system in Jinja District, Uganda, focusing on its ecological condition, user characteristics, perceived drivers of change, and community adaptation strategies. Using a mixed-methods design combining structured household surveys, in-depth focus group discussions, and systematic field observations this study gathered insights from 257 wetland users and key institutional stakeholders. Findings revealed four core insights. First, long-term climate data revealed inter annual variability in rainfall, with no significant trend, and a ~2°C rise in temperature over 40 years, likely intensifying evapotranspiration and stressing wetland hydrology. Second, satellite imagery revealed a greater than 50% loss of wetland area alongside a fivefold increase in built-up and agricultural land, which has fragmented the wetland area and increased the incidence of flooding. Third, water samples showed elevated biological oxygen demand (BODs) up to 80 mg/L, chemical oxygen demand (COD) up to 130 mg/L, elevated coliforms, and a 10–15% drop in Shannon diversity at highly degraded sites. Fourth, household interviews showed that changes in wetland’s ecological status have affected fish abundance and other wetland-derived services, especially for low-income households. Adaptation strategies are diverse, depending on the impacted user, but can broadly be grouped into four categories: diversification (especially for the low-income households), innovation, participation, and modification (especially for users who mainly degrade the wetland). Four logistic regression models, representing each of the adaptation strategies above, showed that training, income, awareness, and gender increase the odds of adaptation, while age and experience reduce the odds of adaptation. In conclusion, this study showed evidence of climate variability at a local scale, consistent with the regional and global trends. There is also evidence of significant land cover change, but this is primarily driven by human activities rather than climate variability. Wetland ecosystem services (using water quality, biodiversity, and livelihoods as proxy indicators) are also likely more threatened by anthropogenic stressors (habitat degradation) than by climate variability. Based on these findings, it is vital to strengthen policy enforcement, integrate user groups into development initiatives, and support local initiatives with training, compensation, and incentives. These measures may enhance both the resilience of wetlands and the livelihoods of local communities.