The shrinkage and plant diversity of Rucece Wetland, Mbarara City

Abstract

Urban wetland ecosystems play critical roles in sustaining human livelihoods. Unfortunately, these ecosystems continue to be degraded despite the several interventions. Understanding the level of degradation and factors associated with this degradation is crucial in designing management interventions. This study sought to assess the level of shrinkage as well as factors associated with degradation of Rucece wetland in Mbarara City, western Uganda. This study used mixed methods design involving quantitative and qualitative approaches. Quantitative approaches involved household surveys as well as spatial analysis using geographical information tools. Semi structured interviews were employed to randomly selected households where a total of 309 respondents were interviewed within Nyakayojo Division in Mbarara City. Nyakayonjo Division was purposively selected for this study as it is where Rucece wetland is located within the city. Satellite images for 2022, 2010, 1998, and 1986 were downloaded and analyzed using remote sensing techniques. Meanwhile, key informant interviews were used for people knowledgeable about shrinkage and plant diversity of Rucece wetland. These key informants were identified using purposive sampling techniques. Results indicate shrinkage of Rucece wetland by 45.8% between 1986 and 2022. A total of eighty-nine plant species, mainly dominated by Mariscus sieberanus followed by Typha latifolia and Sida cordifolia were identified in Rucece wetland. The major plant species within Rucece wetland included sedges and herbs that declined rapidly further away from the core of the wetland. Herbs showed the highest plant species diversity H’= 3.6 followed by food crops H’= 2.41 and trees H’= 2.3. Sida cordifolia was the dominant plant species among the herbs, Solanum tuberosum among food crops while Eucalyptus grandis was the dominant plant species among trees. Subsistence farming (86%), vegetation extraction (78%), harvesting wetland bioresources (61%) and commercial agriculture (51%) were found to be the greatest direct drivers of degradation of Rucece wetland. The local community associated the wetland with supporting, regulating, provisioning and cultural values. The trend of supply of these values was said to be declining potentially undermining livelihoods of communities around. The implications of these results for community livelihoods and biodiversity conservation are discussed. There is need to incorporate scientific information on wetland cover and plant diversity changes as well as peoples’ perceptions on the drivers and use-values of Rucece wetland in its conservation strategy