Guinean Forests of West Africa

Mohamed Bakarr⁵⁵, John F. Oates⁵⁶, Jakob Fahr⁵⁷, Marc Parren⁵⁸, Mark-Oliver Rödel⁵⁹ and Ron Demey⁶⁰

The Guinean Forests of West Africa Hotspot extends from Guinea and Sierra Leone eastwards to the Sanaga River in Cameroon. These forests originally covered an estimated 620 314 km² and form the westerly part of the Guineo-Congolian Regional Center of Endemism defined by White (1983). Although biogeographically distinct, the hotspot comprises two forest blocks: the Upper Guinea block, which extends from Guinea to Togo; and the Nigeria-Cameroon block, extending to the Sanaga River. The two units are separated by the Dahomey Gap in Benin, an area that is now a mixture of farmland, derived savanna woodland, and relict patches of dry forest.

Although the West African forest region traditionally is separated from the Central African forests by the Cross River in eastern Nigeria, the hotspot as here defined extends into Cameroon as far as the Sanaga River (Oates 1986; Martin 1991; IUCN 1996), and includes such high-priority areas as Korup National Park and the Cameroon Highlands. The Nigeria-Cameroon border region is under a level of threat comparable to that of Upper Guinea. The hotspot also includes several important montane regions, such as the aforementioned Cameroon Highlands (the high point being Mount Cameroon, at 4 095 m) and the Upper Guinea, or Greater Nimba, Highlands, between Guinea, Sierra Leone, Liberia, and Côte d'Ivoire.

The two major forest blocks in this hotspot also correspond to two important centers of endemism: Upper Guinea, which corresponds to that portion of the hotspot west of the Gap, and the Nigeria-Cameroon border region plus Bioko Island. The region from Ghana to the Cross River is transitional and supports overlapping generalist species shared by the two forest blocks, such as the mona monkey (Cercopithecus mona) and chimpanzee (Pan troglodytes, EN).

Also included in this hotspot are four islands located in the Gulf of Guinea to the west of the southern limits of the region (and sometimes referred to as the “Galápagos of Africa”): Bioko (Fernando Po; 2 017 km²) and Annobon (Pagalu; 17 km²), both now part of Equatorial Guinea; and São Tomé (857 km²) and Príncipe (139 km²), which together constitute an independent nation. Bioko is a continental-shelf island, supporting a much more diverse flora and fauna, but with a relatively low rate of endemism at the species level, whereas the remaining three are oceanic and relatively depauperate because of their isolation, but rich in endemic taxa (Jones 1994).

The Guinean forests include a range of distinct vegetation zones varying from moist forests along the coast, freshwater swamp forests (for example, around the Niger Delta), to dry, semi-deciduous forests inland with prolonged dry seasons. Of all West African countries, only Liberia lies entirely within the moist forest zone, although a substantial portion of Sierra Leone also falls within the boundaries. In Ghana, derived savanna reaches the coast around Accra, where the average annual rainfall falls below 1 200 mm. This savanna merges into the highly threatened dry forest of the Togo-Volta Highlands and the Dahomey Gap, which ends in eastern Benin. Moist forest continues from there —originally uninterrupted—through the Cross River region in southern Nigeria to Cameroon.

Vascular plant diversity for the entire Guinea-Congolian phytochorion has been estimated to be close to 12 000 species, with 6 400 endemics (Davis et al. 1994). Upper Guinea alone holds about 2 800 species, of which nearly 25% are lianas, while some 530 vascular plants are endemics (Poorter et al. 2004). Site-specific studies such as those of Cable and Cheek (1998), who recorded 2 435 plant species from Mount Cameroon (49 of them endemic), suggest that overall plant diversity in the Guinean forest ecosystem may be as high as 9 000 species. Based on these figures, knowledge of the 185 endemics recorded from the Gulf of Guinea, and using endemism in the Upper Guinea block as an indication of endemism overall, the figure for vascular plant endemism for the region as a whole is estimated at 20%, or 1 800 species.

The Guinean Forests Hotspot also contains a rich and unique faunal assemblage. An important feature of the Guinean forest fauna is that many of the endemic species tend to have highly restricted ranges within the hotspot, making many of these species extremely vulnerable to forest destruction. For example, the Upper Guinea Highlands are home to an exceptionally high number of endemic bats and amphibians with restricted ranges, all of which are Critically Endangered or Endangered.

About 63 of the estimated 320 mammal species are endemic to the region; in addition, there are seven endemic genera, including monotypic genera such as the Liberian mongoose (Liberiictis kuhni, EN). Another monotypic genus, the pygmy hippo (Hexaprotodon liberiensis, VU), an appealing miniature of its huge cousin, is endemic to Guinean forests, with one subspecies in Upper Guinea and one in the Niger Delta. This hippo is an important flagship species, as are a handful of other Upper Guinea endemics such as Jentink's duiker (Cephalophus jentinki, VU), the zebra duiker (C. zebra, VU), the Diana monkey (Cercopithecus diana, EN), and Preuss' guenon (C. preussi, EN).

Avian diversity is also particularly high, with an estimated 793 species that are considered to occur regularly in this hotspot, of which 75 species and six genera are endemic. BirdLife International recognizes most of the Guinean Forests as a conservation priority for birds, with five Endemic Bird Areas (EBAs) lying partly or entirely within the hotspot. These include the Upper Guinea Forests, with 15 species confined entirely to this EBA, including the Liberian greenbul (Phyllastrephus leucolepis, CR); and the Cameroon Mountains, with a remarkable 27 endemic species, among them the enigmatic Mount Kupe bush-shrike (Telophorus kupeensis, EN). São Tomé, Príncipe, and Annobon are all considered distinct EBAs.

Reptile and amphibian diversity is less well documented. Preliminary minimum estimates indicate 206 species of reptiles and 246 species of amphibians, of which roughly 52 reptiles and 83 amphibians are endemic to the region as defined. There are also seven endemic amphibian genera, and a single endemic reptile genus (Cophoscincopus) comprising three lizard species. Many more species are likely to be discovered; for example, during the last ten years, 11 new frog species have been described from the region and many more still await description. Spectacular species in this region are the goliath frog (Conraua goliath, EN), the world's largest anuran; and the Mount Nimba toad (Nimbaphrynoides occidentalis, CR), a species outstanding for its reproductive biology in that, following a gestation period of nine months, they give birth to fully developed toadlets.

There are an estimated 512 species of freshwater fishes in this hotspot, about 35% of which are endemic, making it a truly remarkable area for fish biodiversity. About 25% of the world's 350 species of killifish occur in this hotspot, and about half of these are endemic. Cichlid fishes also feature prominently in this hotspot, with 37 (out of 62) endemic species and five endemic genera. Four of these endemic genera (Konia, Myaka, Pungu, and Stomatepia) are known only from Lake Barombi Mbo, a crater lake in northwest Cameroon.

The Guinean Forests Hotspot is one of the most severely threatened forest systems in the world, with extreme habitat fragmentation and degradation throughout most of the region. According to Forest Resources Assessment 2000 figures, remaining forest cover in each of the countries within the hotspot totals 716 200 km2, although this includes all of Cameroon, which falls only partly in the hotspot. Other earlier estimates put remaining forest cover at 15% for the entire Guinean forest ecosystem, including the islands (Sayer et al. 1992; WRI 1992; Parren and De Graaf 1995). Taking the more or less pristine forests into consideration, we believe that the total is considerably less, but in the absence of more solid figures we use the figure of 15% in our global analysis.

Presently, the major threat is deforestation, due to commercial logging and slash-and-burn agriculture, both of which are prevalent in all Guinean forest countries. Plantation agriculture (e.g., oil palm, rubber, bananas, and cacao) has been very significant in replacing forest in Côte d'Ivoire, parts of Ghana, southern Nigeria, western Cameroon, and Bioko. There is already a negative feedback of deforestation on the regional and local climate, resulting in decreased annual precipitation and prolonged dry seasons. Most of the moist and dry forests within the Guinean region are already at the climatic margin where the respective forest types can persist. The coupled effects of global and regional climate change seriously threaten vast stretches of the remaining areas that today are still forested.

Both small-scale and industrial-scale mining are also serious threats to the remaining Guinean forests. In many of the countries, particularly in the Upper Guinea Highlands, forests are located on substrates that are often rich in high-grade iron ore, diamonds, gold or bauxite. In addition, the Gulf of Guinea harbors one of the richest oil fields on a global scale.

Bushmeat hunting is one of the major threats to larger animal species in the Guinean forests. Although bushmeat has long been an important component of the diet of rural West Africa, growing urban populations, improved road networks, and increased access to forests have created a huge commercialized trading system for it both nationally and internationally. Numerous studies have indicated that the bushmeat trade in the region is enormous; estimates of its value in Ghana run as high as US$400 million per year and for Côte d'Ivoire, $500 million (see Bakarr et al. 2001). Although it is unlikely that the bushmeat trade can ever be completely controlled in an area where it is such an integral part of the culture, efforts should be made to curb or eliminate hunting of the most extinction-prone species, such as red colobus monkeys (Oates et al. 2000). If such efforts are not promoted, then we will likely see full realization of an “Empty Forest Syndrome” whereby, structurally, forest looks rather undisturbed, but in which the larger mammals are either reduced to very small numbers or completely extirpated (see, for example, Oates 1999).

The region's political instability has also contributed to forest destruction. In the 1990s, the United Nations High Commissioner for Refugees documented over a million refugees fleeing civil wars and persecution in Liberia and Sierra Leone and seeking safety in Guinea, Côte d'Ivoire, and Ghana. This number has increased significantly in recent years with the outbreak of conflict in Côte d'Ivoire. Refugee communities impact forests by settling in uninhabited areas, placing increasing pressure on resources through demands for fuelwood and food resources such as bushmeat. Environmental impacts of refugees do not necessarily end when peace accords are signed, and indeed can be exacerbated. Many times, there is a need for more land during repatriation and resettlement. Very often the only uninhabited land available is in forest parks and reserves.

Weak and inefficient governance constitutes a problem in most of the countries in this region, again meaning that laws and protected areas on paper may not be well enforced. One of the outcomes is that illegal logging is on the rise since timber is becoming scarce. For instance, Ghana is able to produce one million cubic meters sustainably from its forest reserves and the wider agricultural landscape. However, in 2002, Ghana's Minister for Lands and Forestry admitted that “the total quantity of logs removed in 1999 amounted to 3.7 million cubic meters, four times the annual allowable cut.”

Since the late 1960s, efforts have been under way in all the countries to establish more strictly controlled, and effectively managed, protected areas. However, the area of forest incorporated into strict protected areas is still small compared to the area of closed forest cover remaining in each of the countries. An analysis of the protected areas coverage in this hotspot yields some interesting results. Approximately 17% of the original extent of the hotspot is considered to have some form of protection; however, when one considers only those classified in IUCN categories I to IV, then the percentage drops to just 3%. The management of protected areas such as national parks has been almost universally lax, with rampant hunting still occurring, except in limited areas where there are long-term wildlife research projects.

To ensure long-term survival of many forest species, it is imperative that remaining forest areas be given more adequate protection and that as many existing forest reserves as possible be elevated to National Park status. While this is being done, it is also important to consider broader landscape approaches, identifying mechanisms like corridors, in order to connect these fragmented protected areas with one another through whatever means possible (Parren et al. 2002). In 1999, Conservation International held a prioritysetting workshop in Elmina, Ghana, which defined priority actions and areas for the Upper Guinea forest block (Bakarr et al. 2001). The following year, the U.S.- based World Wildlife Fund organized and led a similar process for the Congo Basin forests, and extended it to the Nigeria-Cameroon forest block. The two workshops have together established a regional vision for biodiversity conservation in the entire Guinean forests, and should stimulate transboundary conservation initiatives and foster integration among West African countries.

Although civil strife in Côte d'Ivoire, Liberia, and Sierra Leone continues to pose major constraints for conservation investment in the hotspot, moderate progress has been made with the regional conservation vision. With the five-year, $5-million investment in the Upper Guinea forest block from the Critical Ecosystem Partnership Fund (CEPF), most priority areas and actions identified in the region are already being addressed. The CEPF investment has been particularly crucial in mobilizing locally based conservation organizations as well as civil society groups, mainly through partnerships with international organizations. In addition, CEPF investment has also catalyzed new investments from bilateral donors and the private sector. For example, CI and local partners are implementing conservation activities in the Upper Guinea Highlands with support from the U.S. Agency for International Development (USAID) and Rio Tinto. The Global Conservation Fund at CI is also contributing significantly through innovative mechanisms to increase the area of forests under protection across the hotspot.

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