Socio-ecological impacts of invasive alien cactus (Opuntia) in the rangelands of Narok County, Kenya

Abstract

Many cactus species have been introduced in the Kenyan rangelands and their subsequent spread have had devastating effects on the ecosystem services. Opuntia stricta is the most widespread and forms dense impenetrable thickets that negatively impact on rangeland livelihoods and resources. This study assessed the impact of O. stricta on rural livelihoods and their environment in Narok County. Data was collected using household surveys, key informant interviews and transect-walks. Results indicate that communities in the region are well aware of Opuntia invasion in the area, which has increased rapidly over the recent past and spreading to various ecosystems. The cause of spread was attributed to planting the species for various purposes, garden throw-outs and floods. More than 70% of the respondents perceived the species as undesirable with negative impacts only. The impacts include denied access to natural resources, reduced productivity and increased threat to livestock and human health. Pasture lands, farmlands and degraded lands were the most invaded areas. Chopping was the preferred method of management but was combined with other mechanical and chemical methods in order to be more effective. Appropriate interventions are suggested to mitigate the negative impacts and improve rural livelihoods and their environment.

Keywords: Cactus; invasive species; rangelands; rural livelihoods, Narok County