New research urgently calls for biological control and an integrated management strategy in fighting Mimosa diplotricha, an invasive weed that threatens southern and eastern African livelihoods.

The Research and Its Authors

Dr. Arne Witt is the lead author of this study which is entitled, 'Distribution of Mimosa diplotricha in eastern and southern Africa and its socio-economic impacts in northern Malawi. The study was published in the journal Bothalia, African Biodiversity, and Conservation.

The co-authors of the study are Lilian Chimphepo, Tim Beale, and Winnie Nunda. Chimphepo is connected with the Environmental Affairs Department of the government of Malawi.

Objectives and Methodology of the Study

The study authors are scientists from CABI, and their research was conducted in order to establish M. diplotricha's current distribution in southern and eastern Africa. It also sought to determine the weed's impacts on the livelihoods in Malawi's northern region.

The researchers determined the weed's current distribution through literature reviews, data from herbariums, and roadside surveys. They also extended their surveys in Karonga District, specifically to 151 families residing in 32 villages. The weed has devastated the areas chosen for the surveys. The questions in the surveys were designed to determine the weed's impact on the livelihoods of the local population.

According to Witt, M. diplotricha is either an established or emerging weed in a lot of countries worldwide, which include many African countries. In these areas, it has been observed to negatively impact biodiversity and pasture and crop production. It also drives socio-ecological changes.

READ: Invasive Blue Crab Species Wrecks Livelihood of Fishermen in Albania

Results of the Study

Witt says that the researchers found out that the weed is flourishing in the southern part of Tanzania, southeastern and northern Malawi, and in western Ethiopia. It also has isolated populations in Mozambique, Burundi, western Rwanda, and Uganda's Lake Victoria, particularly on its northern shores.

The study found that more than half of all farmers that were surveyed in Malawi's Karonga District think that the weed M. diplotricha reduces their crop yields significantly. In fact, over four decades ago, the plant was already thought to be among the world's 76 worst weeds.

According to many survey respondents, M. diplotricha has been reducing the number of shrubs and grasses in rangelands. More than half of all respondents say it has reduced the yields of their crops. In addition, the weed is also affecting the availability of important medicinal plants as well as other natural resources.

In addition, all the respondents agreed that the weed was hampering the movements of livestock and people. Most of the interviewees also said that the weed also negatively affected trees.

What Can Be Done About It

According to Witt, M. diplotricha can potentially extend its range significantly in some parts of southern and eastern Africa. Thus, they consider it urgent for stakeholders to develop an effective integrated management strategy and implement it widely. Such a strategy needs to include biological control.

As part of the management strategy, it is imperative to work with the affected communities. Inhibiting the weed's further spread calls for an information campaign about the plant's negative impacts and the best management practices that must be implemented in all the affected regions.