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Woody species and trait diversity-functional relations of green spaces in Kumasi, Ghana

Nero, Bertrand Festus
Urban ecosystems 2019 v.22 no.3 pp. 593-607
agricultural land, biodiversity conservation, carbon sequestration, cities, developing countries, ecological function, ecosystems, filters, forests, green infrastructure, home gardens, indigenous species, landscapes, life history, microhabitats, public parks, rangelands, species richness, surveys, trees, urban areas, woody plants, Ghana
Urban biodiversity is essential to creating resilient and sustainable cities. Nevertheless, there is paucity of data on the characterization of microhabitat effects on species/trait diversity and diversity-functional relationships in urban landscapes especially in developing countries. The objectives of this study were to; 1) analyze tree species diversity and composition of urban green space (UGS) types and urban zones, (2) describe the life history diversity of UGS types and urban zones and 3) examine the links between species and life history trait diversity and species productivity (carbon storage) in Kumasi, Ghana. Stratified random sampling was adopted in surveying 470 sampling plots and six streets of lengths ranging from 50 m to 1 km. About 176 tree species in 46 families were recorded within Kumasi. About 96 species were in an adjacent natural forest located at the outskirts of the city. Home gardens, institutional compounds, and public parks had the highest species richness of 76, 75 and 71, respectively while urban rangelands and farmlands were the least species rich with 6 and 23, respectively. Species richness (S) in the peri-urban (LDUZ, S = 142) and core urban (HDUZ, S = 108) were significantly different (Χ² = 15.7, p < 0.0001, n = 1). Native species richness was lowest in the core urban area and highest in the natural forest. Pioneers and anthropochory dispersed species were the most abundant, suggesting that this urban landscape is shaped by both environment and social filters. Tree species diversity and distribution depend on the type of UGS and portrays a perturbed landscape in the early seres of succession with the overall ecosystem function sustained by both species and life history trait diversities. The implications of these findings for improving urban biodiversity conservation and overall urban sustainability are discussed.