Plant diversity patterns of a settlement in the North–West Province, South Africa

Abstract

In recent years the composition of urban vegetation has become far more complex than that of the surrounding natural vegetation. This is mainly due to the influence that humans have on the creation of new plant communities and the management of urban green spaces. Green spaces are fundamental to the restoration and maintenance of biodiversity in areas that have been severely impacted by urban development. Green spaces provide various ecosystem services and benefits for the health and well-being of urban residents, and can help to reduce the effects of global climate change. The most understudied green space in the entire urban green infrastructure is homegardens. Homegardens contribute greatly to the species composition of urban and rural settlements and are important in situ conservation sites that help to protect rare and endemic species. They are essential agricultural systems, especially in rural settlements, that provide both sources of additional income generation and food supply. In developing countries such as South Africa, very few studies have been done on homegardens and the benefits they provide to homeowners and to urban ecosystems in general. However, since South Africa become committed to the United Nations Millennium Development Goals in 2000, more research has been done on the potential of homegardens for poverty alleviation. The aim of this study was to determine the patterns of plant diversity in a rural settlement and to determine to what extent the socioeconomic status of the inhabitants influences the plant species composition of the settlement. The settlement of Ganyesa, situated in the Bophirima district in the North-West Province, was chosen for the study. Using GIS techniques, a grid was placed over the settlement and plant surveys were done every 500 m. Different land-use types were identified during the completion of the survey, namely natural areas, fragmented natural areas, fallow fields, road verges, wetlands, home gardens and institutional gardens. The national South African census data from 2001 proved to be too unreliable to accurately determine the SES of the residents in Ganyesa. Consequently, a social survey was completed by means of a questionnaire to determine the socioeconomic status of the owners of the homegardens under study. Clear differences could be observed between the land-use types and the indigenous and alien species composition, which were indicated in kriging maps. In comparison with the natural areas, homegardens contained more alien species than the surrounding natural areas. The vegetation composition for all the homegardens were correlated with the residents socioeconomic status along a socioeconomic gradient, ranging from low, to medium to high. ANCOVA, multiple regressions and basic statistical analyses were performed using all the vegetation and socioeconomic data. Meaningful correlations occur between the socioeconomic status of the homeowners and the plant diversity of their gardens.