Potential Impact of Alien Invasive Plant Species on Ecosystem Services in Botswana: A Review on Prosopis juliflora and Salvinia molesta

Abstract

Perceptions about the ability of alien species to provide superior ecosystem services over the native species have motivated their importation and distribution across the world. While these species may be providing goods and services, some have now escaped the area of their introduction and invaded other ecosystems posing a threat to biodiversity and ecosystem services. Invasion by alien species threaten achievement of Sustainable Development Goal 2 (food security), 6 (water availability), 12 (sustainable consumption and production patterns) and 15 (protecting ecosystems and forests). This article discusses the potential impact of terrestrial invasive plant, Prosopis juliflora and aquatic weed, Salvinia molesta on ecosystem services in Botswana. Information for this study was collected by review of academic journal articles on the invasiveness of P. juliflora and S. molesta and their impacts on ecosystem services in Africa and other developing countries. The literature review has shown that P. juliflora has the potential to lower water table in water-limited ecosystems, resulting in negative impacts on biodiversity and ecosystem services. In some countries P. julifolia inhibits growth of keystone species hindering their capacity to provide services. A Salvinia molesta invasion in the Okavango Delta, Botswana, has the potential to decrease ecosystem services. It will, thus, impact negatively on the welfare of the riparian communities who depend on fishing and tourist-related activities for their livelihoods. The review contributes towards understanding of the impacts of terrestrial and aquatic invasive plant species on ecosystem services, and importance of biodiversity and ecosystem services in achievement of Sustainable Development Goals. The review further recommends quantifiable monetary assessment of the services delivered by different ecosystems. Such assessment provides information on the value of ecosystem services and can yield information on how much is lost due to invasion by alien plant species.