Impacts of invasive alien trees on recharge into the Atlantis aquifer on the West Coast of South Africa
The climate projections for Sub-Saharan Africa by 2050 shows that rainfall could drop by 10%, which would reduce drainage by 17% and freshwater resources in many countries, e.g. South Africa, is under severe pressure which results in low agricultural production and subsequently reduced food security (Misra, 2014). The invasion of natural ecosystems by invasive alien species is a major environmental problem because they threaten the sustainable benefits derived from such ecosystems (Van Wilgen et al., 2001). Little information is available on the environmental and economic impacts of invasive alien species on groundwater because research is focused more on the history, ecology and management of these species.
The largest programme in Africa called the “environmental management programme” (EMPr) was launched based on economic arguments and since there are ten million hectares of South African land that have been invaded by approximately 180 species, their impacts are still not fully understood (Van Wilgen et al., 2001). Invasive alien species were introduced in South Africa many years ago and they were able to grow and spread all over the country because of human redistribution of species to support agriculture and forestry (Vitousek et al., 1996).