Earlier this year, an online symposium, as part of World Wetlands Day,
discussed best practices for ecosystem restoration, green infrastructure and youth engagement to accelerate actions to conserve and restore wetlands under the theme “It’s Time for Wetland Restoration”. The symposium was organised in partnership with Wetlands International Japan (WIJ), the Global Environment Outreach Centre (GEOC) and the Ministry of the Environment of Japan and stressed the importance of synergistic action addressing interlinked issues, highlighted integrated approaches and encouraged active participation of youth in the United Nation’s Decade for Ecosystem Restoration. It included wetlands restoration, which benefits not only biodiversity and ecosystems, but also contributes to climate change mitigation and adaptation, disaster risk reduction, and human well-being.
Wetlands across the world are being lost with only 13% of their former extent remaining and its restoration is a nature-based solution contributing to flood control and sustainable agriculture.
The Situation in Africa
Wetlands in Africa probably conform to this picture, but data on trends in African wetland extent is limited but some indicators suggest increasing pressure on African wetlands since the 1990’s, such as the decreasing WET Index (UN WCMC, 2017) and the threat status of wetland-dependent species in Africa.
Major threats include development of hydropower dams, with as many as 200 new projects planned in Sub-Saharan Africa continuing population growth and agricultural and urban development. African wetlands are important for their global contribution to ecosystem services on which hundreds of millions of rural communities depend directly for their livelihoods.
African countries have made remarkable progress with developing policies for wetland conservation and management. Fifty African nations are signatories to the Ramsar Convention on Wetlands, with 415 Ramsar sites. However, implementing wise-use strategies remains challenging due to a lack of capacity for policy implementation and knowledge gaps with respect to wise-use. African countries are looking for a sustainable pathway between wetland development, for sustaining the livelihoods of millions of people; and wetlands conservation, to maintain ecosystem service and biodiversity values of wetlands.
One of the prerequisites of adequate wetland management policy is knowledge of the extent and status of wetlands in a country. Wetland inventories in Africa are often incomplete and monitoring is rare with barriers to effective monitoring ranging from data availability and quality to willingness and capacity to use monitoring data. Experts conclude that the application of common, policy-relevant indicators, scaling up of traditional and appropriate new tools and protocols and capacity and partnership building are the main tasks ahead.
South Africa
Wetland management is often hindered by a lack of dedicated expertise and money. A first full wetland inventory of the Mountain Zebra National Park in South Africa (SA), using existing data, imagery and a participatory approach, selected a subset of target sites to assess wetland condition. Significantly, none of the target sites were National Freshwater Ecosystem Priority Areas, highlighting the importance of the participatory approach.
Wetland classification in SA emphasises the landscape setting of wetlands as a basis for classification, but scientists propose inclusion of geomorphic processes of wetland formation in a new genetic geomorphic classification system. The first level of the hierarchical classification considers sediment source responsible for wetland formation, followed by the wetland type. This approach could be extended to include all wetlands and can be used to complement existing classifications.
Mapping and accurately predicting wetland occurrence and extent and ecological condition from remote sensing data remains challenging. In a case study of wetlands in the Western Cape in SA, a Bayesian model approach to predict hydro geomorphic types, were applied with four variables, groundwater depth, relief ratio, slope and elevation particularly important in building accurate models.
The linear nature of rivers makes the protection of many species difficult with multiple stressors added along the river continuum. In an analysis for the Cape Fold Ecoregion, in protection of freshwater fishes under the existing protected area network, showed the majority of freshwater fish species are inadequately protected. Increasingly, non-invasive sampling methods are gaining importance for monitoring freshwater fish. The detection probability using visual observation methods, snorkel surveys and underwater camera trapping, were compared to environmental DNA sampling.
Namibia
Large, tropical, shallow lakes are highly productive ecosystems and to manage these types of lakes both for species conservation and for inland fisheries, it is important to understand how the lake food webs respond to seasonal flooding and drying. In Lake Liambezi in Namibia, three major pelagic food chains, two benthic based and one phytoplankton-based; the latter the longest food-chain, involving four trophic transfers. Restoring this food chain would lend stability to the ecosystem.
Uganda
The impact of surface water nutrient pollution from agriculture and urbanisation on water quality and nutrient and sediment retention in the downstream Namatala Wetland in Uganda, were investigated. It was found that nutrient concentrations were significantly higher in urbanised streams upstream of the wetland than in rural streams.
Ethiopia
In Ethiopia, the potential of three natural riverine wetlands to retain pollutants and to improve water quality downstream in Jimma Town Ethiopia, were investigated showing that the wetlands did indeed retain pollutants, negatively affecting the ecological integrity of the wetlands themselves. This highlighted the fact that water quality needs to be managed to the point that the receiving wetlands are not damaged and can effectively mitigate pollution. A second study supported these findings.
Kenya
The idea that wetlands are converted for agriculture or human settlement, mainly because they are perceived as wastelands is brought into question by the fact that despite increased awareness of the importance and value of wetlands, the habitats are continually degraded and lost. Scientists found that work on the Anyiko wetland in Kenya, the conversion of the wetland was dependent on the socio-economic standing of households and not perception of value, calling for a shift in the institutional regulatory framework towards intersectional collaboration and incentives for wetland restoration. Also at Anyiko wetland, greenhouse gas emissions from rice paddies with and without fertiliser application, was assessed. The report found that fertilisation had no effect on methane or carbon dioxide emissions, but caused substantial increase in nitrous oxide emissions. Overall the study suggested that cultivation and land preparation is responsible for a loss of organic carbon, limiting the ability of the wetland to store carbon.
The future
Submissions of these inter- and multidisciplinary African wetland researches are all highly relevant to policy and management for sustainable management, traditional and novel monitoring methods, climate change mitigation and water quality and quantity regulation. The number of scientific publications on African wetlands has risen in the last two decades with a strong involvement of European researchers and funding.
Data on wetland loss in tropical Africa is scarce, but it seems reasonable to assume that the degree of forest and river degradation is still lower than in other parts of the world. Scientists opine that Africa can still aim for a development trajectory towards sustainable catchment management and wise use of wetlands straight away without first losing wetland ecosystem services and then having to restore them in the future, as in Europe and North America.
To achieve this, a major effort should, besides the traditional conservation of protected wetlands, go into strengthening integrated landscape management and sustainable agriculture and urbanisation.
