Mexican sunflowers (Tithonia species) are promoted as a green manure, but a survey of rural farmers revealed that these species are invasive, and have substantial negative impacts in addition to their benefits.
Because resources for addressing environmental problems are limited, it has been suggested that management should focus on those species that have the highest impacts in their new environments. Comparing the ability of alien and native species to utilize resources has been shown to offer a sound approach for identifying alien species with high impacts.
Understanding the trade-offs of invasive alien species for people’s livelihoods and the environment is becoming more prominent to help guide management and to avoid conflicts. One way of framing these benefits and costs are as ecosystem services and disservices.
Prof Dave Richardson from the DST-NRF Centre of Excellence for Invasion Biology (CIB) at Stellenbosch University (SU) and a world leading scientist in the field of invasion biology, is the recipient of the 2018 Kwame Nkrumah Award for Scientific Excellence.
Alien grasses occurring in South Africa have been associated with negative environmental and socio-economic impact across the globe. Some grasses can increase the intensity and frequency of fires due to their large biomass, and many grass species invade areas such as agricultural land leading to reduced crop yield and quality.
