Status and trends of biodiversity, including benefits from biodiversity and ecosystem services
The total number of species recorded in the country to date is 3,339 derived from 17 taxonomic groups. The country is endowed with 1,005 flowering plants, 126 species of mammals, 627 species of fishes, 566 species of birds, 784 species of insects and 77 species of reptiles.
The 2014 Waterfowl Census reveals that the population and distribution trends of waterbirds have seriously declined due to the overflooding of wetlands resulting in the subsequent invasion of aquatic species, such as phragmites and typhae. Due to the absence of large predators, there is an increase in the number of hippos, warthogs, baboons and monkeys that has led to a series of reported human-wildlife conflicts. Also, the Bijol Islands provided the only known breeding site in The Gambia for Grey-headed gulls, Royal terns, Caspian terns, Reef herons and Briddle tern. However, the islands are no longer suitable for the breeding of Grey-headed gulls and Reef herons due to sea level rise which has subsequently wiped out the vegetation, such as morning glory, casaurina and the baobab tree. This area is also no longer suitable for breeding turtles since it is frequently overflooded. Urbanization, tourism and related industrial developments along the Atlantic Coast have removed large areas of coastal vegetation, the habitat for many species that depend on coastal and marine biodiversity, such as marine turtles and vervet monkeys.
The National Forest Inventory (2009) reveals that the country’s terrestrial surface was in the past covered by dense forest, estimated at 43% of the total land area. To date, the country has lost over 13 species of mammals and an unknown number of floral species. Results of the National Forest Assessment indicate that, regardless of the forest type, the great majority (more than 50%) of the forest is Secondary Young, while smaller fractions of areas (around 30%, but more than 40% for Semi Deciduous) is Secondary Mature. Primary forest is constituted by about 11% of the area of Evergreen Forest but in smaller percentages in other forest types. This is the result of heavy exploitation in the past for charcoal and timber production.
Agriculture is the backbone of the economy. The sector is supported by the Government and engages nearly 70% of the active population. The decline in crop yield (e.g. groundnuts, cotton, sesame) constitutes a serious reduction in productivity. Some crops have had their diversity enhanced as a result of the introduction of other varieties from outside the country, such as New Rice for Africa (NERICA). As for livestock, some cattle breeds are on the decline. For instance, the West African shorthorn cattle, which constituted about 80% of the national cattle population in the 1990s, now constitutes about 47% of the national cattle herd.
Fisheries resources are provided from two sources, the River Gambia and the ocean. The estimated total biomass of demersal and pelagic fish resources in Gambian waters is 22,000 tons and 156,000 tons, respectively. The total fish potential from the maritime fisheries is estimated at about 88,000 tons with demersal and pelagic fish resources constituting 21% and 78%, respectively. Total annual fish production was around 38,000 tons in 1996, clearly indicating a surplus potential. Certain fish species, such as the lobster (Palinurusspp
), shark, catfish (Arius heudeloti
) and the white grouper (Epinephelusaetheus
), are threatened as a result of unsound human exploitation strategies. Based on the current production levels, there is considerable scope for exploiting marine pelagic fisheries and aquaculture. In contrast, there is great need for tighter and more effective control of threatened demersal resources.
Main pressures on and drivers of change to biodiversity (direct and indirect)
Examples of threats to biodiversity include the cutting of trees, including in mangrove forests, for fuel wood (it is reported that the forest provides 85% of domestic energy needs for over 90% of the population); unregulated and illegal hunting practices; destructive fishing practices (including illegal fishing gear, intrusion by foreign trawlers); illegal harvesting of thatch grasses and the cutting down of tree branches to collect wild fruits; shifting cultivation and itinerant farming practices; bushfires; overgrazing; industrial and household waste dumping into wetlands; illegal coastal sand mining activities; pollution; the proliferation of “chain saw machines” that further advances the ability of humans to destroy indigenous woody tree species. Moreover, land tenure rights and the demand for land outside traditional farming areas are steadily leading to the massive cutting down of mangroves to cultivate rice in the North Bank Region. In addition, local-level intervention to restore rice ecologies through the construction of non-environmentally-friendly anti-salt dams in the region has resulted into the abandoning of potential rice-growing zones in areas such as Farafeni, Kosemar, FoniJarrol, etc. The three most persistent threats on protected areas resources are logging, infrastructural developments and land conversion.