Determining the invasive potential of Crotalaria agatiflora (Crotalarieae, Fabaceae) in South Africa
T. Phago.1,2, B-E. Van Wyk.1, J.S. Boatwright.3
1Department of Botany and Plant Biotechnology, University of Johannesburg, P. O. Box 524, Auckland Park, 2006, Johannesburg, South Africa.
2Invasive Species Programme, South African National Biodiversity Institute, Private Bag X7, Claremont, 7735.
3Department of Biodiversity and conservation biology, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa.
Crotalaria agatiflora is native to the tropical East Africa with its distribution mainly occurring in Tanzania, Kenya and Ethiopia. In South Africa this plant was introduced as an ornamental garden shrub, but because it invades natural vegetation ( savannah biome, grasslands, watercourses and forest margins) in Gauteng, North West, Limpopo, Mpumalanga, Free State, Kwazulu-Natal and some parts of the Eastern Cape Provinces. It is proposed that it be listed as a category 1a invader under the National Environmental Management: Biodiversity Act (NEM:BA). We used standard methods to explore and monitor five populations of this species. We recorded more than thirty populations of this species in addition to the SAPIA records around Gauteng, measured and counted the number of individuals in populations. We predict the future distribution of the species based on climatic suitability. Soil seed bank show that Crotalaria agatiflora is a slow but persistent invader. Its seed coat dormancy and ability to resprout makes it very persistent. The preliminary scientific data obtained from this study show that C. agatiflora poses a significant threat to the flora of South Africa and that it should be controlled. This study supports the listing of this species as a category 1a invader especially in Gauteng where the number of recorded populations are increasing greatly.