Socio-Economic Impacts of Invasive Alien Plant Species of Cactus (Opuntia Stricta) In Ewaso Nyiro Area in Narok County, Kenya.

Abstract

Several plants have been introduced in Kenya for various purposes. Some have become aggressive and rapidly colonize and out-compete the indigenous vegetation. Among them are the Opuntia (Cactus pear) species, one of them being Opuntia stricta Haworth, which was introduced as an ornamental but has spread widely in natural ecosystems especially in the drylands. However, information about its impacts to livelihoods and the sources of spread has not been well documented. This study investigated the challenges faced as a result of invasion and the factors that contribute to the spread. It was done in Ewaso Nyiro, one of the most invaded areas in Narok County, using questionnaires where a sample size of 50 was purposively selected since the area is not densely populated. Impacts caused by Opuntia stricta invasion included denied access to land, injury to both human and livestock and reduced farm- land and pasture-land, land productivity and the well-being of the community. Although majority of the respondents were not aware of how the species got into their farms, some thought that the main source of spread was due to planting the species as an ornamental and a fence. Others thought that it was spread mostly by floods since new invasions occurred immediately after the rainy season. The most common plants affected by O. stricta invasion were indigenous vegetables such as terere (Amaranthus), stinging nettle (Urtica dioica), African nightshade (Solanum), spider plant (Cleome gynandra) and pumpkins (Cucurbita pepo) since they were mostly found on the fence and farm edges and this heavily impacted on the food security. The main methods used to control were chopping, burning, burying and use of herbicides. These methods posed challenges in terms of practicality, expense and environmental impacts and therefore other sustainable methods should be identified that can assist in control as well as improve livelihoods. This should integrate the reported benefits such as source of food, fodder and medicine in order to sustainably manage the species.