Environmental degradation of the Saloum river Estuary, Senegal

Problems

• Decline of Mangrove Forests

  The mangrove forests of the Saloum River Estuary suffered severe losses during the Sahel drought decades of the 1970s-1980s: an early assessment (UNEP/GRID) estimated roughly a 25% decline in mangrove area and density since the early 1970s, driven mainly by reduced rainfall and hydrological changes that raised salinity to levels inhospitable for some mangrove species.
  
  Since rainfall began recovering in the late 1990s, however, peer-reviewed remote-sensing research (Andrieu et al., 2020, Forest Ecology and Management) has documented substantial regeneration, including an estimated 3,600 hectares of mangrove gain between 2000 and 2015, about 96% of it occurring spontaneously rather than through planting. The Delta's mangroves should therefore be understood as a vulnerable, only partially recovered ecosystem rather than one in continuous decline. They remain ecologically critical, providing habitat for wildlife, nursery areas for fish species, and blue-carbon storage, so continued monitoring and protection are still needed.

• Unsustainable Exploitation

  Mangroves in parts of the Saloum Delta are harvested for firewood and construction timber, and to support oyster and shellfish harvesting, and in some areas this extraction has contributed to habitat loss. However, a 2020 peer-reviewed study (Andrieu et al.) found that community resource use was not the primary driver of overall mangrove change across the Delta, and more recent research on shellfish harvesting (Ndour et al., IntechOpen) documents sustainable practices already used by several communities, including selective harvesting, rotational collection sites and seasonal rest periods intended to conserve oyster stocks. Continued support for these community-led sustainable practices, together with alternative livelihood and energy options, remains important to reduce pressure on remaining mangrove stands.

• Impact of Climate Change

  Climate variability is a significant long-term risk for the Saloum River Estuary. Severe rainfall deficits during the Sahelian drought of the 1970s-1990s sharply increased salinity across the estuary and drove major mangrove dieback; rainfall subsequently recovered from the late 1990s onward and contributed to mangrove regeneration, but future rainfall variability remains an important climate risk rather than a settled trend in either direction.
  
  The Delta's coastline is also highly dynamic: research covering 1954-2018 documented substantial erosion around the Saloum mouth and identified the system as vulnerable to climate-related coastal change, and rising sea levels threaten to increase salinity intrusion into freshwater sources. These changes affect mangroves, migratory birds, fish stocks and the fisheries and food security of local communities that depend on them.

• Pollution and Water Quality Degradation

  Pollution is a recognized general risk for estuarine ecosystems, and coastal areas of the Saloum Delta face localized pressures from plastic waste and other land-based pollutants common to West African coastal zones. However, robust site-specific water-quality data for the Saloum Estuary (for example, documented nutrient loading, eutrophication, harmful algal blooms, or fish kills) is currently limited in the published literature. This section should be treated as an area requiring further local monitoring rather than an established, measured impact; continued water-quality monitoring is needed to determine the real extent of pollution pressures on the estuary's ecosystems and on the communities that depend on fishing and aquaculture.

• Loss of Biodiversity

  The Saloum River Estuary, part of the Delta du Saloum UNESCO Biosphere Reserve and Ramsar wetland, is home to a rich diversity of species, including large breeding and wintering colonies of migratory waterbirds (UNESCO records more than 30,000 pairs of royal terns), fish, shellfish, and other wildlife. Certain fish, shellfish and benthic communities show signs of pressure or declining abundance in more heavily exploited locations: a 2023 study found shellfish harvesting significantly reduced the abundance and biomass of benthic infauna in affected areas, and fisheries monitoring from 2020-2022 reported declining diversity and abundance in some fishery resources. These localized pressures, combined with habitat change from climate variability and resource use, threaten the cultural and economic practices of local communities that depend on these species for their livelihoods, even though the Delta as a whole remains internationally recognized as an exceptionally important biodiversity site.