GEO-6 Regional Assessment for Africa


as cited in the fifth National Report of Eritrea (de Grissac and Negussie 2007) the Red Sea represents a complex and unique tropical marine ecosystem with extraordinarily rich biodiversity and a remarkably high degree of endemism. It is one of the most important repositories of marine biodiversity on a global scale and features a range of significant coastal habitats. The southern part of this sea is rich in marine plants, especially seagrasses, which are the only group of higher plants (flowering plants) adapted to life submerged under the sea. The Eritrean Red Sea ecosystem hosts 12 of the world’s 60 existing seagrass species (Grissac and Negussie 2007), and is also known for diverse coral reefs, with about 38 coral reef genera and 220 species recorded in the area. The Eritrean coastline and islands are vegetated with different species of halophytes and a few non-halophyte plants such as grasses and trees, including several mangrove species: Avicennia marina, Ceriops tagal, Avicennia tagal and Rizophora mucronata.


Thieme et al. (2005) attributed threats to aquatic ecosystems to the disturbance of water bodies by damming, water diversion and pollution. Additionally, activities on land adjacent to water bodies have significant impacts on the health of aquatic ecosystems (Stiassny et al. 2011). These activities include major urban development along rivers and lakes, inland agricultural activities and forest logging. The introduction of alien species has been observed to affect some freshwater bodies.


Developments currently underway in most African countries will have severe effects on freshwater bodies and associated wetlands. All four major rivers (Congo, Niger, Nile and Zambezi) have dams and three of them (Niger, Nile and Zambezi) have already been significantly affected by their presence. The construction of a large dam on the Nile will certainly affect the freshwater habitats of the river, while the projected Grand Inga Dam in the Democratic Republic of the Congo will have a similar impact if constructed without proper environmental impact assessment and well-planned scenarios to mitigate potential future effects.


In recent years, the impacts of mining on the waters and soils of African ecosystems have been identified and are considered very serious. For example, the upper reaches of the Olifants catchment (South Africa), which is part of the larger Limpopo Basin and hosts large-scale coal mining, coal- fired power generation plants and a diverse array of heavy and light industries (Ashton 2010), contains high concentrations of trace metals. These concentrations are suspected of causing the large-scale fish deaths that were observed over the last few decades in Lake Loskop, which is at the heart of the Olifants catchment (Oberholster et al. 2011; Ashton 2010). This type of problem has also been documented for many of the rivers and water bodies of Southern Africa (Ochieng et al. 2010). Beyond the biodiversity impacts of mining, the accumulation of high levels of metal ions in African rivers renders fish unfit for human consumption and poses problems for irrigated crops and domestic use of water from affected freshwater bodies. Contamination of freshwaters in Africa and its potential effects on biodiversity as well as humans, has also been reported in other regions, including the upper Congo (Atibu et al. 2013).


The scramble for cultivatable lands will also affect freshwater bodies and associated wetlands. This includes the recent acquisition of large land areas by commercial interests for agriculture in Ethiopia, Ghana, Mali, Mozambique, Senegal, Tanzania (Kachika 2011) and South Sudan (De Schutter 2011). Major agricultural developments have been reported in Kenya (Klopp 2000), and agricultural expansion is also slowly entering the Congo Basin, where massive projects have been initiated. A quantitative inventory conducted in Ethiopia, Ghana, Madagascar, Mali, Mozambique, the former Sudan and Tanzania (Cotula et al. 2009) found schemes to bring 25 000 square kilometres under cultivation for large agricultural development. Such land-use change may deplete forest biodiversity and, as documented by Foley et al. (2005), demands on water resources for irrigating the arid zones of the continent have a significant impact on water stocks, draining groundwater and freshwater ecosystems and associated wetlands. Furthermore, clearing forest and other land habitats leads to erosion, which if combined with


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