The Lower Guinean forests also known as the Lower Guinean-Congolian forests, are a region of coastal tropical moist broadleaf forest in West Africa, extending along the eastern coast of the Gulf of Guinea from eastern Benin through Nigeria and Cameroon.
The Dahomey Gap, a region of savanna and dry forest in Togo and Benin, divides the Lower Guinean forests from the Upper Guinean forests to the west, which extend along the western coast of the Gulf of Guinea from Togo to Liberia and north to Guinea. To the north and northeast, the Lower Guinean forests transition to the drier inland Guinean forest–savanna mosaic and Northern Congolian forest–savanna mosaic and to the southeast are bounded by the Congolian Coastal forests, whose boundary is the Sanaga River in Cameroon. The Lower Guinean forests share many biotic affinities with the Upper Guinean forests but are located in Sierra Leone. They are collectively known as the Guinean Forests of West Africa.
The Lower Guinean forests represent an ecological region in West and Central Africa. Stretching along the Gulf of Guinea in West Africa, these forests encompass parts of Nigeria, Cameroon, Equatorial Guinea. The Lower Guinean forests are globally recognized as a biodiversity hotspot, characterized by their ecological significance and species diversity.
Ecoregions The World Wide Fund for Nature (WWF) divides the Lower Guinean forests into a number of distinct ecoregions:
Nigerian lowland forests (Benin, Nigeria) Niger Delta swamp forests (Nigeria) Cross–Niger transition forests (Nigeria) Cross–Sanaga–Bioko coastal forests (Nigeria, Cameroon, Equatorial Guinea) Cameroonian Highlands forests (Nigeria, Cameroon) Mount Cameroon and Bioko montane forests (Cameroon, Equatorial Guinea) São Tomé, Príncipe, and Annobón moist lowland forests (Equatorial Guinea, São Tomé and Príncipe)
The WWF has designated two regions of the Lower Guinean forests as Global 200 priority regions for conservation. The WWF's "Coastal Congolian forests" region includes the Cross-Sanaga Bioko coastal forests, São Tomé and Príncipe moist lowland forests, and Atlantic Equatorial coastal forests ecoregions. The "Cameroon Highlands forests" Global 200 region includes the Cameroonian Highlands forests and the Mount Cameroon and Bioko montane forests ecoregions.
Geographical features
Tropical rainforests These forests primarily consist of tropical rainforests, characterized by high rainfall, lush vegetation, and a wide variety of plant life. The region's rainfall is relatively evenly distributed throughout the year.Darwall, W., Polidoro, B., Smith, K., & Somda, J. (2015). Ecosystem profile guinean forests of West Africa biodiversity hotspot. Critical Ecosystem Partnership Fund Report.
Flora and fauna
The Lower Guinean forests are recognized as one of the world's biodiversity hotspots. They are home to a vast array of plant and animal species, many of which are endemic.
Lower Guinean forests are known for their rich botanical diversity, including numerous tree species, epiphytes, orchids, and medicinal plants. The forests support diverse wildlife, including various primates (such as chimpanzees and gorillas), big cats (like leopards) and forest elephants, numerous bird species, reptiles, amphibians, and insects.
Ecological significance
Carbon storage These forests play a critical role in sequestering carbon dioxide, helping to mitigate climate change. Their extensive vegetation stores significant amounts of carbon.Dixon, R. K., Winjum, J. K., & Schroeder, P. E. (1993). Conservation and sequestration of carbon: the potential of forest and agroforest management practices. Global Environmental Change, 3(2), 159-173. The Lower Guinean Forests help mitigating climate change by offering capacity for carbon storage. The extensive and diverse vegetation that thrives within this biome serves as a substantial carbon sink, effectively sequestering carbon dioxide from the atmosphere.
Numerous studies and scientific reports have emphasized the importance of these forests in the fight against climate change. Research findings underscore that the Lower Guinean Forests store significant amounts of carbon and serve as a buffer against the rising levels of atmospheric CO2. This sequestration function underscores the invaluable role played by these forests in supporting global efforts to reduce the impacts of climate change.
Water regulation The forests regulate water flow, helping to prevent flooding during heavy rains and ensuring a steady supply of freshwater to rivers and streams.Blumenfeld, S., Lu, C., Christophersen, T., & Coates, D. (2009). Water, wetlands and forests. a review of ecological, economic and policy linkages. In Secretariat of the Convention on Biological Diversity and Secretariat of the Ramsar Convention on Wetlands, Montreal and Gland. CBD Technical Series (Vol. 47, pp. 1-38). The water regulation function of the Lower Guinean Forests is another crucial aspect of their ecological significance. These forests act as natural sponges, absorbing and releasing water in a manner that benefits both the environment and human communities. During periods of heavy rainfall, they play a critical role in preventing flooding by absorbing excess water and regulating its flow. This not only safeguards the ecosystems within the forests but also safeguards human settlements downstream from potential deluges. The forests ensure consistent freshwater supply to rivers and streams, sustaining local aquatic ecosystems and providing water resources for human communities. Aquatic life and vegetation depend on these water bodies.
Habitat for endangered species Several critically endangered species, including the Cross River gorilla and various species of monkeys and birds, inhabit the Lower Guinean forests.Oates, J. F., Bergl, R. A., & Linder, J. M. (2004). Africa's Gulf of Guinea forests: Biodiversity patterns and conservation priorities (p. 90). Washington, DC: Conservation International.Mittermeier, R. A., Valladares-Pádua, C., Rylands, A. B., Eudey, A. A., Butynski, T. M., Ganzhorn, J. U., ... & Walker, S. (2006). Primates in peril: the world's 25 most endangered primates, 2004–2006. Primate Conservation, 2006(20), 1-28. The Lower Guinean Forests serve as a refuge for a diverse range of wildlife. Among the most emblematic inhabitants of these forests is also the Cross River gorilla, an elusive and highly endangered primate species. These forests are also home to multiple other species, including various monkeys, birds, and numerous plants with unique ecological significance. Forest preservation is necessary for the survival of these vulnerable species. Conservation efforts in the Lower Guinean Forests are crucial to maintaining the biodiversity of the region and ensuring the protection of these species.
Cultural and indigenous importance These forests are often home to indigenous communities with rich cultural traditions. The forests provide resources and are central to the way of life of many local people.Fairhead, J., & Leach, M. (1996). Misreading the African landscape: society and ecology in a forest-savanna mosaic (No. 90). Cambridge University Press. These forests supported diverse cultural traditions and lifestyles that have thrived for generations. The Cultural and Indigenous Importance of the Lower Guinean Forests extends beyond their ecological significance, reflecting a profound connection between the region's indigenous communities and the forest environment. Understanding and acknowledging this cultural dimension is integral to appreciating the holistic significance of these forests.
Threats and conservation
Deforestation The Lower Guinean forests are under threat from deforestation due to logging, agriculture, mining, and infrastructure development. This threatens both biodiversity and carbon storage. While not limited to this region, each cause contributes to the ongoing degradation of this ecosystem.
Commercial logging: Commercial logging is a major driver of deforestation in the Lower Guinean forests. Valuable timber species are harvested for export and domestic use, leading to a significant loss of forest cover. Examples include the extraction of mahogany (Swietenia spp.) and sapele (Entandrophragma cylindricum) for international markets. A study by the World Resources Institute (WRI) highlighted the impact of logging in this region, revealing that it accounts for a substantial portion of deforestation. Agricultural expansion: The expansion of agriculture, including slash-and-burn farming, plays a substantial role in forest loss. Local communities clear forested areas to make way for crop cultivation, particularly in areas where subsistence farming is prevalent. Examples include cocoa cultivation, oil palm plantations, and subsistence farming practices. A report from the Rainforest Foundation UK documented the expansion of cocoa farming in the Lower Guinean forests and its detrimental impact on the environment. Mining activities: Mining for valuable minerals such as gold and bauxite results in deforestation in the Lower Guinean forests. The extraction of these minerals leads to the clearing of large areas of forest and generates pollution, disrupting local ecosystems, e.g., during gold mining activities in Ghana and Guinea, widely reported as contributing to deforestation. The Global Forest Watch platform provides data on mining-related deforestation in these regions. Infrastructure development: The construction of roads, highways, and other infrastructure projects often necessitates clearing significant portions of forested land. As human populations continue to grow, there is a growing demand for improved transportation networks, leading to further deforestation. The fragmentation of forest habitats due to infrastructure development isolates populations of various species and obstructs their migration.
Habitat fragmentation Habitat fragmentation is a pressing concern in the Lower Guinean forests, threatening the integrity of this ecosystem. The expansion of human activities, including infrastructure development and agricultural expansion, has led to the fragmentation of forest habitats, making it increasingly challenging for wildlife to thrive, disperse, and maintain genetic diversity. This phenomenon is especially relevant to the Lower Guinean forests and has far-reaching ecological consequences which include limiting the ability of wildlife to access necessary resources, find suitable mates, and maintain genetic diversity. Smaller, isolated populations of species face an increased risk of inbreeding and reduced adaptive capacity. Additionally, fragmented habitats are more vulnerable to edge effects, such as increased predation, invasive species, and altered microclimates. These consequences of habitat fragmentation pose significant challenges to the conservation and long-term sustainability of the Lower Guinean forests.
Illegal wildlife trade Illegal wildlife trade and poaching pose substantial threats to the region's fauna and flora, encompassing illegal capture, sale, and transportation of wildlife primarily for bushmeat and exotic pet markets. The trade encompasses the illegal capture, sale, and transportation of wildlife, and it primarily targets species for bushmeat and the exotic pet trade.