Biodiversity of the urban homegardens of Sao Luis city, Northeastern Brazil

摘要

There is a widely held notion that the increasing trend of urbanization accelerates loss of biodiversity and displaces native species. This study assessed the validity of this notion in the city of Sao Luis the capital of the state of Maranhao in the northeastern Brazil. The specific objectives of the study were to (1) assess plant and animal diversity of urban homegardens, (2) compare the diversity of homegardens in terms of origin of these species (exotic or indigenous to Brazil). We conducted a biodiversity survey in 40 randomly selected 'quintals' (hereafter called homegardens) from ten locations in the city of Sao Luis. We evaluated the species richness and diversity of various use categories of plant and animal species indigenous to Brazil as well as exotic species. A total of 186 species of plants in 68 families were recorded in the sampled homegradens. A total of 63 fruit tree species representing 34% of all tree species were found. Of these species, those indigenous to Brazil accounted for 58% of the cases, and this was significantly higher than the exotic species. Most of the species (60%) were indigenous to Brazil (wild and semi-wild domesticates), while the rest (40%) were exotic. A total of 42 species of vertebrates (mainly reptiles, birds and mammals) were also found in the homegardens, of which 47% were indigenous to Brazil. Some of the plant and animal species found in the homegardens are endangered species in their native habitats, suggesting that homegardens could provide a unique opportunity for their conservation and sustainable use. These species continue to play a vital role in the socioeconomic and ecological landscape of the city.