Mangrove forest ecosystems are critically threatened in West-Central Africa due to minimal management and policy efforts. This is partly caused by insufficient knowledge about the economic and ecological value of mangrove ecosystems, which provide important ecosystem services, such as fish, flood prevention, erosion prevention, water regulation, and timber products. A strategy to improve mangrove ecosystem management would be to improve public understanding of the ecosystem's values. We studied these drivers on a regional scale, using socio-economic and grey literature and consultations with experts, thereby focusing on the period from 1980 to 2006. Wood harvesting, conversion of mangroves for agriculture, and bio-fuel plantations were important drivers of mangrove forest change. Coastal development is the most important direct driver of mangrove forest change, especially between 2000 and 2006, a period that coincides with large oil discoveries in the region. About 60% of all industries within the region are located near the coast, which is expected to attract about 50 million people by 2025. Future policies should target the risks of declining mangrove ecosystems in West-Central Africa. This requires focusing on adaptive strategies, reviewing existing coastal and marine ecosystem policies, and developing an integrated coastal management strategy for the region.

We present results of the field assessment using a total of fifteen 0.1 ha mangrove permanent sample plots (PSPs) in four selected countries in Central Africa, including: Cameroon, Gabon, Republic of Congo and Democratic of Republic, which together account for 90 % of mangroves in Central Africa. Above-and belowground carbon stocks were computed using data from the PSPs in all four countries. Long-term monitoring data in Cameroon were used to estimate carbon sequestration rates. Four major carbon pools were considered: aboveground carbon, belowground root carbon, deadwood and the soil organic carbon. All the eight mangrove species described in Central Africa were encountered in the study. The dominant species in Central Africa is Rhizophora racemosa, and it occupies more than 70 % of the forest formation. The average stand density ranged from a low of 450 tree/ha in degraded forest of RoC to a high of 3,256 tree/ha in undisturbed stands of Cameroon. Standing volume ranged from a low of 213 m 3 /ha in RoC to a high of 428 m 3 /ha in Cameroon; corresponding to aboveground biomass values of 251 and 505 Mg/ha, respectively. Together with the deadwoods, the total vegetation biomass in the study area ranged from a low of 394 Mg/ha in RoC to a high of 825 Mg/ha in Cameroon. Mean diameter increment for primary and secondary stems was 0.15 cm/year. This translates to above-and belowground annual biomass increments of 12.7 and 3.1 Mg/ha/year, respectively. Total ecosystem carbon in undisturbed system was estimated at 1520 ± 164 Mg/ha with 982 Mg/ ha (or 65 %) in belowground component (soils and roots) and 538 Mg/ha (35 %) in the aboveground components. Carbon density differed significantly (p \ 0.05) with forest

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Fuel wood extraction for commercial fish smoking is the most pervasive threat to the sustainability of mangrove ecosystems in the Douala-Edea Wildlife Reserve (DEWR) of Cameroon and most West-Central African coastal states. The high rates of fuel-wood consumption are associated with fish smoking in this region and are chiefly the result of low fuel efficiency systems. In this study, we investigated the relative efficiency of two fish-smoking systems with respect to fuel wood consumption and time required for fish smoking in the DEWR. Using socioeconomic and forest surveys in three villages, where mangrove wood is harvested and used, we established that the annual fuel-wood off-take was about 42,839m 3. In addition, most of the wood is used for fish smoking in the Traditional Smoke System (TSS) method, which was assessed to be 70% less efficient than the Improved Smoke System (Eeyed/CWCS). The Eeyed/CWCS consumed on average 50% less wood than the TSS, and reduced fish-smoking time by up-to 65% relative to the TSS. This comparative advantage offers opportunities for reducing the incidence of smoke-related diseases in women and children-most of them involved in the smoking process-by reducing the time spent smoking fish and saving money from avoided additional wood consumption. However, these benefits can only be achieved through the successful introduction of the Eeyed/CWCS. This will require a broad range of sensitization, capacity enhancement, and further research on adapting the current model to local conditions of the area.

An ethnobiological survey of 174 local resource users was conducted in the Lower Sanaga Basin to assess the current conservation status of West African manatee (Trichechus senegalensis, Link 1795) within lakes, rivers, and coast (including mangroves, estuaries and lagoons). Using a multistage sampling design with semi-structured interviews, the study asked three main questions: (i) are manatees still present in Lower Sanaga Basin? (ii) If present, how are their numbers evolving with time? (iii) What are the main threats facing the manatee? Each of these questions led to the formulation and formal testing of a scientific hypothesis. The study outcome is as follows: (i)60% of respondents sighted manatees at least once a month, regardless of habitat type (rivers, lakes, or coast) and seasons (dry, rainy, or both); (ii) depending on habitat type, 69 to 100% of respondents perceived the trend in manatee numbers as either constant or increasing; the increasing trend was ascribed to low kill incidence (due either to increased awareness or lack of adequate equipment) and to high reproduction rate; and (iii) catches (directed or incidental) and habitat degradation (pollution) ranked in decreasing order as perceived threats to manatees. The catch incidence is threefold larger on lakes than in rivers and more adult manatees are caught than juveniles. Pollution occurs in several places by fishing enterprises, industrial plantations and individuals. The perceived incidence of boat collisions is presently negligible compared to catches and habitat degradation. A twelve-point strategy is set forth for improving manatee conservation in the study area.