About the project

Many exotic trees and shrubs have been introduced into Africa, but a few have escaped  cultivation and become destructive alien invasive species reducing native biodiversity and limiting the livelihoods of those that live in rural communities.

So what’s the problem?
Woody species such as invasive Prosopis spp, Lantana camara and Chromolaena odorata are some of the worst offenders. In South Africa alone, the costs to ecosystem services were estimated at USD 1 billion per year. Some developed countries have rolled out large programmes to mitigate the negative impacts of woody invasive species. But in Eastern Africa, where those living in rural communities are more vulnerable to the impacts of invading species, there is a lack of coordinated and effective sustainable management of woody alien invasive species.

What is this project doing?
The aim of the project is to mitigate the negative effects of woody invasive alien species on biodiversity, ecosystem services and human well-being in East Africa.

To achieve this goal, the team will generate and share knowledge on how the invasive species establish and spread and on the effects and impacts of the invaders in the different contexts of Ethiopia, Kenya and Tanzania. The project team will also develop and improve measures for controlling the species, which will be built into Sustainable Land Management strategies that will help the countries to mitigate the impacts of the species.

Project activities:

  • Assessing the relationship between abundance of the invasive and their impacts at a local level
  • Mapping current and potential future distribution of selected woody invasive alien species in case study areas on local and country level and using this information to raise awareness of the problem
  • Developing and evaluating management options: biological, physical and chemical control
  • Developing, testing and disseminating strategies to mitigate negative effects of woody invasive species

Geographic scope
The project will be implemented in Ethiopia, Kenya and Tanzania. In each country, the activities will primarily focus on one case study area and selected focal species:

Woody weeds project areas

Woody weeds project areas

Afar region: Prosopis invasion along Awash river and ethnic conflicts due to reduced
access to grazing land and water.
Baringo district: Degradation of grazing lands and lawsuits against the government
for sanctioning the introduction of Prosopis.
East Usambara: Global biodiversity hotspot: invasions into remnant forest blocks
threathen biodiversity, and invasions by Lantana camara into the surrounding
agricultural land lead to cropping pattern change.




To understand how the effects of woody invasive species upscale from the local to the national level, small-scale field studies will be combined with field surveys, remote sensing and species distribution modelling using GIS-based spatial analysis to assess the current and potential distribution of selected woody invasive alien species in the study areas.

Using the results
Invasive alien species are key drivers of anthropogenic global environmental change as they threaten native biodiversity, ecosystem services, but there is only limited understanding of the mechanisms that link these environmental impacts with impacts on rural livelihoods. Both economic and non-economic valuation information is increasingly needed.

The project’s research findings will inform the development of practical mitigation strategies from the local to the national scale and, underpinned by active engagement with policy-makers, lead to the development of a policy environment that is conducive for widespread application of sustainable land management approaches that will mitigate the negative impacts of woody invasive alien species.