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Improving lives by solving problems in agriculture and the environment

Woody weeds in East Africa

Many exotic trees and shrubs have been introduced into Africa and become destructive invasive species. They're reducing native biodiversity and limiting the livelihoods of those that live in rural communities. CABI is trying to mitigate these impacts in East Africa by generating and sharing knowledge on their effects and finding ways that they can be controlled.

Project Overview

So, what's the problem

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.

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.

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.

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.

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.

Results

The project has just begun and the first stakeholder workshop will be taking place at the beginning of June in Nairobi. This provides a great opportunity for project members and the PhD candidates to meet and understand the issues the stakeholders from each project country are facing. 

The team

Project Manager

Staff image of Urs Schaffner

Urs Schaffner  Head Ecosystems Management

Rue des Grillons 1 CH-2800 Delémont
Switzerland
T +41 (0)32 4214877
E u.schaffner@cabi.org

Project team

Staff image of René Eschen

René Eschen

Research Scientist, Ecosystems Management, and Risk Analysis and Invasion Ecology

Documents