Very few studies have been conducted on invasive species in Nigeria, however a new study in mongabay.com’s open access journal Tropical Conservation Science has discovered 25 invasive plants in a field gene bank at the National Center for Genetic Resources and Biotechnology (NASGRAB) in Ibadan. The gene bank is used to establish populations of important and, in some cases threatened, native plant species.
The gene bank spans 12 hectares, but the study found that 18% of the area was overtaken with invasive species that likely compete with the protected Nigerian plants for nutrients, space, and light. Among the 25 invasive species, 14 were herbs, 8 were vines, 2 were shrubs, and one was a tree.
Chromolaena odoratahas proven a costly invasive species in Africa. Commonly known as Siam weed, Christmas bush, or the common floss flower. Photo by: Ashasathees.
“The most aggressive species are the [vines or] climbers that spread both horizontally and vertically along wide perimeters, colonizing every area within their reach,” the author, Temitope Israel Borokini, writes, adding that these climbers threaten canopy cover and trees and thereby impact the microclimate of forests. A change in the microclimate, in turn, can hurt a wide-variety of animal and plant species.
Of particular concern, according to the author, is the North American Chromolaena odorata.
The invasive plants were likely brought-in by visitors, since the gene bank is open to the public. In addition, the protected area has had difficulties with farming encroaching on the land.
“Most invasive species, once established, becomes permanent. Eradication is possible in a few instances, but only at great expense and effort,” writes Borokini. “Most others require control, which may be said to be successful when the plant no longer exceeds a threshold level determined by the objectives of the managers.”
Borokini suggests training technical officers in invasive species, updating laws and awareness of invasive species in Nigeria, as well as improving the exchange of technical information on invasive species across African nations.
CITATION: Borokini T. I. 2011. Invasive Alien Plant Species in Nigeria and their effects on Biodiversity Conservation. Tropical Conservation Science Vol. 4 (1):103-110.
(02/19/2011) The tiny state of Cross River, Nigeria, has managed to preserve large swathes of endangered rainforest despite lucrative – and often intimidating – offers from loggers and other interests. It’s also laid the groundwork for a state-wide program designed to earn international carbon credits by saving trees, thus securing its spot in an elite network of states that are moving forward as UN talks stall.
(11/17/2005) Nigeria has the world’s highest deforestation rate of primary forests according to revised deforestation figures from the the Food and Agriculture Organization of the United Nations.
(01/18/2008) The ‘real’ costs of invasive species are underestimated in developing countries, argues a new report that calls for more research into the environmental, social and economic impact of non-native plants and animals.