Many invasive species provide both benefits and costs to society and the environment. These benefits include aesthetic
values, but also provide resources such as timber, fuelwood, fodder and food. However, these invasive species can have costly
consequences. For example, they reduce the supply of ecosystem services such as water and grazing, reduce native biodiversity and have
negative impacts on local economies. Species that have both benefits of and costs can lead to conflicts of interest and have often
hindered effective management.
A recently published study by C·I·B PhD student, Ross Shackleton, looked at one such conflict-species –
Prosopis or mesquite. Interviews were conducted with several communities to compare the household use and perceptions of mesquite
as compared to native trees.
Most households use both native trees and/or mesquite for fuelwood. However, the majority of stakeholders across ten
communities in the Northern Cape still use native trees more than mesquite. This suggests that its direct use value for households is not
as important as previously thought, and that native trees, that mesquite displaces, are still more important in the area. This was because
fuelwood from native trees was seen as being of a better quality. The reasons for stakeholders to prefer native trees include: coals from
native trees are longer lasting; wet mesquite wood gives off odorous smoke; large thorns make it difficult to harvest mesquite; and dried
mesquite wood is particularly susceptible to a borer beetle which turns it into pulp faster than in wood from native species. The study
further found that the reliance on both native trees and mesquite is decreasing as the electrification of towns increase.
“This study showed that the impacts of mesquite exceed the benefits, and that conflicts of interest surrounding
mesquite are not as high as previously thought. The improved management of mesquite, for example, through biological control agents, needs
to be implemented to reduce the costs of invasion and possibly improve benefits” explains Ross Shackleton.
The study found that most households use both native trees and/or mesquite for fuelwood. However, the majority of
stakeholders across ten communities in the Northern Cape still use native trees more than mesquite. (Photo credit: Ross Shackleton)
Read the paper:
Shackleton, R.T., Le Maitre, D.C., Van Wilgen, B.W. and
Richardson, D.M. (2015) Use of non-timber forest products from invasive alien Prosopis species (mesquite) and native trees in South
Africa: implications for management. Forest Ecosystems.
For more information, contact Ross Shackleton at firstname.lastname@example.org