Information Center: Environment

Results 51 - 60 of 97


John E Fa, Javier Juste, Jaime Perez Del Val, and Javier Castroviejo
October 6, 1995

The impact of commercial hunting on forest mammals was studied in two regions on Bioko and Rio Muni in Equatorial Guinea, west Africa. Harvests were assessed from carcass counts in the main markets in the areas. A total of 10,812 carcasses of 13 species were recorded in Bioko, and 6160 carcasses of 30 species were recorded in Rio Muni. Biomass of harvested mammals was 111,879.63 kg in Bioko and 66,447.87 kg in Rio Muni. For the 12 prey species selected for study in Bioko, harvests totaled 7.15 animals/km2 or 62.93 kg/km2. Harvests for the 17 prey species in Rio Muni were 3.22 animals/km2 or 24.06kg/km2. We used a model developed by Robinson and Redford (1991) to estimate potential harvests based on animal production rates. Total production was 147.90 animals/km2 and 139.12 animals/km2 in Bioko and Rio Muni, respectively. Potential harvest figures varied considerably by species. Comparison of actual and potential harvests showed that five primate species (Cercopithecus erythrotis, Cercopithecus nictitans, Cercopithecus pogonias, Cercopithecus preussi, and Mandrillus leucophaeus) and one ungulate (Cephalophus ogilbyi) in Bioko were being hunted unsustainably. Only two of the 17 species (Cercopithecus nictitans and Cephalophus dorsalis) in Rio Muni were being hunted unsustainably. Percent deviation of actual from potential harvests averaged 4.98 times greater than sustainable harvest in Bioko and 1.03 times greater in Rio Muni. For the two sites together figures ranged from close to 28 times greater than potential to 0.08% of the potential harvest. Although hunting methods and the commercialization potential of species may affect their presence in markets, these figures show that Bioko animals are heavily exploited, some of them unsustainably. This poses severe risks for the conservation of the island's unique fauna that must be addressed immediately.

John E Fa, Paul J Johnson, Jef Dupain, Juan Lapuente, Pamela KoÌster, and David W Macdonald
November 2, 2004

Bushmeat markets can reflect the impact of hunting in large geographical areas, but efficient and adequate sampling strategies are needed. Five bushmeat markets in West and Central Africa were used to simulate the performance of different sampling regimes. The studied markets (n= 863 days) varied in animal carcasses and number of species recorded. In our simulations, we varied number of days sampled and their temporal distribution using a variant of the Monte Carlo methodology. Three sample strategies were considered: (1) unconstrained random sampling; (2) random sampling of start-points, where the n days sampled are a sequential block following the randomly selected start-point and (3) sampling blocked by season. No substantial differences between standard sampling theory and our simulations were present. However, only a large sample of markets will allow useful inferences on a regional scale and timing and coordination of sampling may be highly influential. Sampling in blocks of days was as efficient as simple random sampling in estimating species richness, but not carcass volume. This may indicate that, even with seasonality in market compositions, or irregular influences, the temporal pattern as described by presence/absence varies much less than does the volume of carcasses. Shorter sampling periods perform poorly in estimating species richness. The relationship between % species richness and overall carcass volume may predict the sampling effort required to estimate market species richness based on volume, when a large enough sample of markets becomes available. Similarly, a larger sample of markets would reveal how far the species composition in markets reflects the general organising principles of community structure in terms of frequency and abundance relationships.

M Puit; A Huart; P Leroy; I N French Nsangou
January 1, 2004

The aim of this study was to do surveys about bush meat networks around urban centers near the Monte Alen National Park in Equatorial Guinea.

Kumpel N.F.; Milner-Gulland E.J.; Cowlishaw G.; Rowcliffe J.M.
January 1, 2008

We studied the impact of current levels of gun-hunting on diurnal primate species in the little-studied Monte Mitra area of Monte Alén National Park, continental Equatorial Guinea.

J. M. Capdevielle
January 1, 1949

Set of three reports and one essay on forestry in Equatorial Guinea, including topics such as conservation, animal species, and flora and fauna.

Julio Mercader, and Raquel Marti
June 8, 1999

Archaeological evidence from the forested lowlands of Equatorial Guinea indicates that human occupation, exploitation, and anthropogenic impact on central African forest biomes date back many millennia and that tropical forest environments may not be the backwater stage for human evolution and cultural development that is often assumed.

Julio Mercader
August 7, 2002

Under the Canopy turns conventional wisdom on its head by providing a well-documented, geographically diverse overview of Stone Age sites in the wet tropics. New research indicates that, as humanity and its precursors increased their geographical and ecological ranges, rainforests were settled at a much earlier period than had previously been thought. Featuring the work of leading scholars from Australia, Brazil, Canada, Colombia, France, Malaysia, Panama, Spain, and the United States, Under the Canopy creates a new niche in paleolithic studies: the archaeology of tropical rainforests. This book provides the first synthesis of archaeological research in early foraging sites across the rainforest zone, and indicates that tropical forests could harbor important clues to human evolution, origins of modern behavior, cultural diversity, and human impact on tropical ecosystems.

Janna Rist, Eleanor Jane Milner-Gulland, Guy Cowlishaw, and J Marcus Rowcliffe
November 8, 2009

Understanding the impact of hunting on wildlife populations is crucial to achieving sustainability and requires knowledge of prey abundance responses to different levels of exploitation. While the abundance of primates has been shown to respond independently to hunting and habitat, habitat is rarely considered simultaneously when evaluating the impacts of hunting. Furthermore, the importance of these two factors in determining the abundance of other species has not been well investigated. We evaluate the independent effects of hunting and habitat on the abundance of a diverse assemblage of species, using a series of predictions and data from a study in Equatorial Guinea.

J Cano, S Nzambo, J N Buatiche, M Ondo-Esono, F Micha, and A Benito
April 8, 2003

Anopheles (Cellia) carnevalei is described in the mainland region (Río Muni) of Equatorial Guinea. Anophelines collected were identical to An. nili with exception of some morphological characters found in wings, head, and legs.

J Cano, P J Berzosa, J Roche, J M Rubio, E Moyano, A Guerra-Neira, H Brochero, M Mico, M Edu, and A Benito
March 7, 2004

The current study was performed on the Bioko Island (Equatorial Guinea) with the aim of establishing a rapid assessment technique for mapping malaria risk and measuring vector densities. Human bait collection, tent traps, light traps, indoor resting collection, and window exit traps were used to collect Anopheles gambiae s.s. and Anopheles funestus, the two anopheline species involved in malaria transmission in this island. Capture data were used to compare differences in the behavior and vectorial capacity of An. gambiae s.s. and An. funestus. Differences in the two species of mosquitoes were found in relation to the season and trapping methods used. Entomological inoculation rates (EIR) for Plasmodium falciparum were calculated using a polymerase chain reaction (PCR) test with individual anopheline mosquitoes from human bait collections in two villages during the dry and rainy seasons. P. falciparum sporozoites were detected from both dissected heads/thorax and abdomens of both species.

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