The role of urban schools in biodiversity conservation across an urban landscape

Previous studies have clearly outlined the importance of urban green spaces such as golf courses, urban gardens and street sides in urban ecosystem functioning. To date little has been done to consider the role of urban school yards in biodiversity conservation in Southern Africa. Our study therefore investigated the role of urban school yards in biodiversity conservation across an urban gradient in the city of Harare, Zimbabwe. Ten schools were randomly selected from each stratum, low, medium and high density suburbs. School yards were surveyed for herbs (garden flowers) and woody plants (trees and shrubs). For a diversity, species richness, Shannon and Simpson diversity indices were computed using the Hill numbers. Variation in species composition among schools was assessed using beta diversity (beta(SOR)) and its components (beta(SIM) and beta(SNE)). A total of 120 tree species belonging to 43 families and 89 garden flowers belonging to 41 families were identified and recorded in school yards from the different suburb densities. Schools in medium density suburbs had highest species richness, Shannon, Simpson and beta diversity indices for indigenous trees compared with those in the low and high density suburbs. For garden flowers, there was no variation in species richness, Shannon, Simpson and beta indices across school yards from low, medium and high density suburbs. Our results demonstrate the important role of urban school yards in biodiversity conservation in general, though there is species homogenization of garden flowers and exotic trees across the urban landscape.