Management and Control of Cestrum aurantiacum in Kenya

Abstract

Cestrum invasion poses substantial threats to agriculture, biodiversity, and delivery of ecosystem services in Kenya. When the species is not controlled, Cestrum forms dense stands in degraded forest gaps, abandoned farmlands, open areas and consequently prevents establishment of other plant species in forest areas. The species competes aggressively with native species mainly due to its allelopathic properties and in turn prevents regeneration and establishment of natural forests. Cestrum is also a major weed in key commercial plantations and croplands in some parts of the Country. Invasion may significantly affect management and economic returns on commercial plantation species such as; Pine, Cypress, Cedar, and Podo among other tree species. Apart from its ability to suppress regeneration of other tree species, Cestrum is also poisonous to livestock and may indirectly affect human health. The extent of Cestrum invasion in water catchments, commercial forest plantations, rangelands and farmlands has captured the public attention. The main challenge with Cestrum invasion is the insufficient information and capacity for its management due to lack of appropriate policies and awareness among government officials and other stakeholders. Cestrum invasion has negatively impacted biodiversity, water resources, crop and pasture production, human and animal health and economic development. However, there is insufficient information to enable management of the invasion. Beware of the argument that introducing a whole bunch of new tree species to an ecosystem or landscape is a good thing “because it increases the tree cover or biodiversity”. Though biodiversity is a global concept, increasing local biodiversity by introducing new species from elsewhere can actually reduce global biodiversity if the introduced species cause extinction of endemic species that are found only in our ecosystem and nowhere else in the world. The enormous diversity of ecosystems and wildlife species are source of livelihood and central to the economy of the country thereby being indispensable to achieving the aspirations outlined in Vision 2030.