Assessment of wetland use/cover change and effects on ecosystem services: a study on Nyamagita Catchment, Masindi district, Uganda

Abstract

Wetlands, also commonly called swamps in Uganda, are estimated to cover about 13% of the total land surface (about 30,000km2) of the country and represent considerable ecological, social and economic resources. However, this coverage is gradually dropping as a result of pressure from anthropogenic activities thereby affecting ecosystem goods and services they provide. A case study of Nyamagita catchment in Masindi District, Mid-Western Uganda was carried out with objectives of: i) tracing the extent of wetland cover changes over the last 20years (2000, 2010 and 2020) and, ii) assessing the effects of the cover changes on provisioning ecosystem services of the catchment. Landsat images of years 2000, 2010 and 2020 covering Nyamagita catchment were downloaded from United States Geological Survey (USGS) / Earth explorer. These satellite images were prepared and classified using ArcMap software principles while basing on spectral characteristics, to produce a map for Nyamagita catchment showing the trend in land use/cover change for the study period. Information about effects of wetland use/cover changes on provisioning ecosystem services was collected from 100 respondents randomly selected from five parishes within the catchment: Nyantonzi, Bikonzi, Kinyara, Kasongoire and Kabango. Data were analyzed using SPSS software. The images revealed a progressive increase in area coverage of: Papyrus/Swamp by 5.71% and Agriculture/Sugarcane by 16.20% while there was a decline in the area coverage of: Forest by 4.54%, Grassland/Other vegetation by 10.47% and Bare ground by 6.90%. According to the respondents, these land use changes caused decline of goods; firewood by 33.0%, fish by 24%, palm tree leaves by 22.9% and pasture by 6.7% the most while goods; domestic water, papyrus, clay, irrigation water and palm tree leaves respectively were the leading goods still available and being obtained from within the catchment by the time of this study. With agriculture likely to continue taking toll on Nyamagita catchment cover, goods like firewood, fish, palm tree leaves, pasture and general biodiversity of the area is likely to continue declining greatly and so will the associated respective activities of firewood collection, fishing, etc.