The effects of Urban sprawl on wetlands vegetation cover in Nakawa division

Abstract

This study assessed the effects of urban sprawl on wetlands vegetation cover in Nakawa Division. The objectives were: (i) determine the spatial-temporal trends of urban sprawl in Nakawa division; (ii) determine the patterns of land use and land cover changes in in Nakawa division; and (iii) determine the effects of wetlands changes on vegetation species diversity. A mixed methods approach was used involving; vegetation assessment survey and secondary data archived retrieval of satellite imagery. Species data was collected using vegetation survey assessment which aimed at identifying various wetlands vegetation species. Satellite imagery for the years 1989, 1995, 2008 and 2020 were used to ascertain the changes in wetlands vegetation cover in Nakawa division. Land use and cover change was analyzed using unsupervised classification approach while, vegetation species was analyzed using relative abundance, a one way analysis of variance (ANOVA) and t-test. The study revealed that there is a tremendous transformation in wetlands vegetation cover in Nakawa division. The built-up area has shown the highest rate of expansion while green area, swamps and generally vegetation species suffered the greatest loss. The increasing urban sprawl has also been shown to lead to a decrease in wetland vegetation cover. Further, I observed an increase in unplanned settlements (slums) encroaching on the wetlands thereby leading to wetlands reduction. With regards to vegetation species, cyperus papyrus, Vossia cuspidata, Sesbania sesban, Nympea caerutea, and Miscanthedium Species were observed. However, wetlands species did not show any significant difference across the three surveyed zones; downstream, middle stream and upstream of the Nakawa division. It is recommended that Nakawa division urban planners should design, implement and periodically review an integrated strategic plan for the existing infrastructure to avert the negative implication of urban growth and development on the existing infrastructure and land in the study area. The study further recommends that comprehensive land use planning and development policies should be introduced, strengthened and incorporated into the Nakawa division master plan.