Freshwater snails (Pila spp.) at a market in Accra, Ghana © Kevin Smith
The results show that western Africa supports a high diversity of freshwater species, of which a significant proportion is threatened. As development increases across the region the status of western Africa’s freshwater biodiversity will worsen unless successful conservation measures can be undertaken.
An immediate priority is to implement conservation actions in the basins that have been identified to contain exceptional levels of species diversity and those containing high levels of threatened species (see Geographic Patterns). These actions need to address the downstream impacts of the key threats, such as agricultural and mining pollution and deforestation often leading to increased sedimentation. If this situation continues along current trends some species will become extirpated from catchments and may become extinct altogether. Ecosystem level consequences of the loss of such species are poorly understood, as are the knock on effects to the services they provide to human populations. It is often the poorest communities that rely most heavily upon freshwater resources, for example, as a protein source (e.g. the local crab fisheries in Mali), for building materials, and for income when subsistence harvest surpluses are sold. Consequently, this poorest section of the community, which has few alternative livelihood options, suffers the most when species are lost or ecosystems are degraded.
EIAs, when correctly undertaken, are a valuable tool for informing the development planning process, particularly where threatened or restricted range species are expected to be found. This report (and the IUCN Red List website) provides data useful to the initial planning stages of EIAs, as the expected species composition of every sub-catchment in the region can be identified, along with information on species ecology, Red List status, threats and utilisation. It should be noted, however, that the spatial data presented are, in most cases, of too low resolution to replace the need for additional field surveys as required for a fully comprehensive EIA.
Protected Areas need to be specifically designed for the protection of freshwater species, particularly those that have restricted ranges or limited numbers of congregation, migration or breeding sites. Design must take good account of the high connectivity within freshwater systems if the Protected Areas are to be effective. For example, the success of a protected area established for freshwater species conservation may be greatly reduced if upstream activities some distance outside the Protected Area boundaries, such as excessive water withdrawal or regulation, may significantly alter the downstream flow regime within the protected area to the detriment of those species being protected. A good understanding of the threats and ecology of the target species, as provided here, is often essential for optimising the design of the Protected Area.
In western Africa there are many transboundary rivers (e.g. the Niger river basin alone passes through nine countries), and as the region continues to develop and populations grow the demand for water in neighbouring countries is going to increase. There is therefore a need for IWRM to be adopted, along with other similar management approaches, such as Environmental Flows. IWRM aims to manage entire river catchments (both water and land) so that the economic and social benefits are maximised while maintaining ecosystem functions (see the Global Water Partnership Toolbox for more information on IWRM and case studies (www.gwptoolbox.org)). Environmental Flows, a component part of IWRM, is a concept based on the understanding that a river’s flow regime is critical to the maintenance of a functioning wetland ecosystem. The approach aims to find a balance between the quantity, quality and timing of water flows required to sustain freshwater and estuarine ecosystems, and the water needs of the associated human population For example, using this approach, the natural flow regime of a river may be maintained or restored (such as through the controlled opening and closing of dams) to allow target species reliant on seasonal fluctuations to be maintained.
There are a large number of Data Deficient species in the region, with between 10% (fishes) and 22% (crabs) of species falling into this category. Further research and survey work are desperately needed to gather more information on these species’ distributions, taxonomy, ecology and their utilisation and threats. Findings from future field surveys will undoubtedly uncover more threatened species, and will likely add to the growing body of evidence that freshwater biodiversity has great value to local livelihoods.
One of the most challenging parts of the process is presentation of the biodiversity assessment outputs in a format which is suitable and accessible to the widest range of stakeholders. In particular, the outputs need to be accessible to natural resource managers, developers and policy makers. This requires production of a range of products, including brief summaries of the issues and recommendations (policy briefs), more detailed technical reports, and comprehensive data sets. This report will serve as the detailed technical report of the assessment findings, and the full database including all species distribution shape files is available as a DVD. Policy briefs will be forthcoming. All species assessments and distribution maps (jpegs) will be directly accessible online through the IUCN website and from the Freshwater Biodiversity Unit.
Identification of the primary end-users of this information is also a challenge given the multitude of different organizations with overlapping and sometime contradictory jurisdiction for the management of wetland ecosystems. Preliminary efforts have been taken to identify these stakeholders through an online survey of end-user data needs but more work needs to be done in this area. The preliminary results can be found at: www.unep-wcmc.org/freshwater_biodiversity/Africa/survey/.
In conclusion, we hope that the information provided through this assessment will be taken up by the key stakeholders in freshwater ecosystems throughout western Africa and will be integrated in the decision making processes for environmental and development planning in wetland ecosystems. In this way, we hope that the future impacts of development actions affecting wetland ecosystems can be minimized and mitigated to the benefit of freshwater species and those people who rely on freshwater species for their livelihoods and pleasure.