Bethan J. Morgan

Devastating Decline of Forest Elephants in Central Africa

African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced.

Elephants, ivory, and trade.

Trade decisions made by the Convention on International Trade in Endangered Species must place science over politics. Tanzania and Zambia are petitioning the Convention on International Trade in Endangered Species (CITES) to “downlist” the conservation status of their elephants to allow sale of stockpiled ivory. But just 2 years after CITES placed a 9-year moratorium on future ivory sales (1), elephant poaching is on the rise. The petitioning countries are major sources and conduits of Africas illegal ivory (2–4). The petitions highlight the controversy surrounding ivory trade (5) and broader issues underlying CITES trade decisions.

Chimpanzee accumulative stone throwing

The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

Conservation of Drill Populations in Bakossiland, Cameroon: Historical Trends and Current Status

Very little information is available on the current status of drill populations in Cameroon. We report on drill group sizes and status in Bakossiland, a mountainous area spanning 2000 km2 in the Littoral and South West Provinces of southwestern Cameroon. Between 1970 and 2002 direct visual counts of drill groups (n = 105) yielded group size estimates ranging from 5 to 400 (mean ± S.E.M.; 93.1 ± 8.4). We encountered solitary adult male drills on 8 occasions. Groups were at all elevations (150–2000 m) in 5 habitat types: lowland, premontane, submontane and montane forests and montane savannah at 2000 m). Group sizes did not vary with respect to elevation, habitat type or season (wet and dry mo). However, over the past decade drills have been virtually hunted out of the Mwenzekong Mountains (Banyang Mbo Wildlife Sanctuary), and they are greatly reduced in the southern Bakossi forests of Mwendolengo, Edib Hills and Mungo River. The species became extinct in the Loum Forest Reserve in the late 1970s, and until recently was thought to have become extinct on Mount Mwanenguba. Since 1994 on Mount Kupe, the drill population has begun to recover, largely due to protection afforded by the Bakossi traditional chiefs. Traditional powers and values are still influential in the region. A new national park—Bakossi Mountains National Park— and associated Protected Areas are currently under gazettment. We discuss the effectiveness of conservation strategies in relation to the survival of drills in the area.

Chimpanzee population structure in Cameroon and Nigeria is associated with habitat variation that may be lost under climate change

BackgroundThe Nigeria-Cameroon chimpanzee (Pan troglodytes ellioti) is found in the Gulf of Guinea biodiversity hotspot located in western equatorial Africa. This subspecies is threatened by habitat fragmentation due to logging and agricultural development, hunting for the bushmeat trade, and possibly climate change. Although P. t. ellioti appears to be geographically separated from the neighboring central chimpanzee (P. t. troglodytes) by the Sanaga River, recent population genetics studies of chimpanzees from across this region suggest that additional factors may also be important in their separation. The main aims of this study were: 1) to model the distribution of suitable habitat for P. t. ellioti across Cameroon and Nigeria, and P. t. troglodytes in southern Cameroon, 2) to determine which environmental factors best predict their optimal habitats, and 3) to compare modeled niches and test for their levels of divergence from one another. A final aim of this study was to examine the ways that climate change might impact suitable chimpanzee habitat across the region under various scenarios.ResultsEcological niche models (ENMs) were created using the software package Maxent for the three populations of chimpanzees that have been inferred to exist in Cameroon and eastern Nigeria: (i) P. t. troglodytes in southern Cameroon, (ii) P. t. ellioti in northwestern Cameroon, and (iii) P. t. ellioti in central Cameroon. ENMs for each population were compared using the niche comparison test in ENMtools, which revealed complete niche divergence with very little geographic overlap of suitable habitat between populations.ConclusionsThese findings suggest that a positive relationship may exist between environmental variation and the partitioning of genetic variation found in chimpanzees across this region. ENMs for each population were also projected under three different climate change scenarios for years 2020, 2050, and 2080. Suitable habitat of P. t. ellioti in northwest Cameroon / eastern Nigeria is expected to remain largely unchanged through 2080 in all considered scenarios. In contrast, P. t. ellioti in central Cameroon, which represents half of the population of this subspecies, is expected to experience drastic reductions in its ecotone habitat over the coming century.

Do large birds experience previously undetected levels of hunting pressure in the forests of Central and West Africa

The commercial bushmeat trade threatens numerous species in the forests of West and Central Africa. Hunters shoot and trap animals, which are transported to rural and urban markets for sale. Village-based surveys of hunter offtake and surveys of bushmeat markets have shown that mammals and reptiles are affected most, followed by birds. However, hunters also consume some animals in forest camps and these may have been overlooked in surveys that have focused on bushmeat extracted from the forest. A number of studies have used indirect methods, such as hunter diaries, to quantify this additional offtake but results can be difficult to verify. We examined discarded animal remains at 13 semi-permanent hunting camps in the Ebo Forest, Cameroon, over 272 days. Twenty-one species were identified from 49 carcasses, of which birds constituted 55%, mammals 43% and other taxa 2%. The mammals identified were typical of those recorded in previous bushmeat studies but we recorded several species of birds rarely recorded elsewhere. Offtake of bird species increased with mean body mass. We extrapolated our results to the 34 known hunting camps in the Ebo Forest and estimated that a minimum of 97 birds are hunted annually in a catchment area of c. 479 km2. We conclude that some bird species may be hunted more frequently than previous research suggests and this has important conservation implications for larger-bodied species such as raptors and hornbills.

The population genetics of wild chimpanzees in Cameroon and Nigeria suggests a positive role for selection in the evolution of chimpanzee subspecies

BackgroundChimpanzees (Pan troglodytes) can be divided into four subspecies. Substantial phylogenetic evidence suggests that these subspecies can be grouped into two distinct lineages: a western African group that includes P. t. verus and P. t. ellioti and a central/eastern African group that includes P. t. troglodytes and P. t. schweinfurthii. The geographic division of these two lineages occurs in Cameroon, where the rages of P. t. ellioti and P. t. troglodytes appear to converge at the Sanaga River. Remarkably, few population genetic studies have included wild chimpanzees from this region.ResultsWe analyzed microsatellite genotypes of 187 wild, unrelated chimpanzees, and mitochondrial control region sequencing data from 604 chimpanzees. We found that chimpanzees in Cameroon and eastern Nigeria comprise at least two, and likely three populations. Both the mtDNA and microsatellite data suggest that there is a primary separation of P. t. troglodytes in southern Cameroon from P. t. ellioti north and west of the Sanaga River. These two populations split ~200-250 thousand years ago (kya), but have exchanged one migrant per generation since separating. In addition, P. t. ellioti consists of two populations that split from one another ~4 kya. One population is located in the rainforests of western Cameroon and eastern Nigeria, whereas the second population appears to be confined to a savannah-woodland mosaic in central Cameroon.ConclusionsOur findings suggest that there are as many as three genetically distinct populations of chimpanzees in Cameroon and eastern Nigeria. P. t. troglodytes in southern Cameroon comprises one population that is separated from two populations of P. t. ellioti in western and central Cameroon, respectively. P. t. ellioti and P. t. troglodytes appear to be characterized by a pattern of isolation-with-migration, and thus, we propose that neutral processes alone can not explain the differentiation of P. t. ellioti and P. t. troglodytes.

Newly Discovered Gorilla Population in the Ebo Forest, Littoral Province, Cameroon

We report on a new population of gorillas discovered in November 2002 in the Ebo Forest, Littoral Province, Cameroon. We observed A group of ≥q7 gorillas directly for 83 min, and they were in auditory range for 155 min. Further evidence of gorilla presence included 8 nest groups totaling 38 nests, distinctive feeding signs accompanied by footprints, and a gorilla cranium collected from the nearby village of Iboti. This newly discovered gorilla population is geographically intermediate between the 2 extant populations of western gorillas: Gorilla gorilla gorilla, the most populous gorilla subspecies living in Gabon, Equatorial Guinea, Congo-Brazzaville, Central African Republic and Cameroon to the south of the Sanaga River, and G. g. diehli or the Cross River gorilla, a small population of ca. 250 individuals on the Cameroon-Nigeria border. It is not possible to assign the new gorilla population to either subspecies on the basis of measurements of the single male cranium. Genetic analyses of freshly shed hairs, collected from gorilla nests, may help to resolve the taxonomic status of the Ebo gorillas.

Genetic signatures of a demographic collapse in a large-bodied forest dwelling primate (Mandrillus leucophaeus).

It is difficult to predict how current climate change will affect wildlife species adapted to a tropical rainforest environment. Understanding how population dynamics fluctuated in such species throughout periods of past climatic change can provide insight into this issue. The drill (Mandrillus leucophaeus) is a large-bodied rainforest adapted mammal found in West Central Africa. In the middle of this endangered monkeys geographic range is Lake Barombi Mbo, which has a well-documented palynological record of environmental change that dates to the Late Pleistocene. We used a Bayesian coalescent-based framework to analyze 2,076 base pairs of mitochondrial DNA across wild drill populations to infer past changes in female effective population size since the Late Pleistocene. Our results suggest that the drill underwent a nearly 15-fold demographic collapse in female effective population size that was most prominent during the Mid Holocene (approximately 3-5 Ka). This time period coincides with a period of increased dryness and seasonality across Africa and a dramatic reduction in forest coverage at Lake Barombi Mbo. We believe that these changes in climate and forest coverage were the driving forces behind the drill population decline. Furthermore, the warm temperatures and increased aridity of the Mid Holocene are potentially analogous to current and future conditions faced by many tropical rainforest communities. In order to prevent future declines in population size in rainforest-adapted species such as the drill, large tracts of forest should be protected to both preserve habitat and prevent forest loss through aridification.

Attempted Predation by Nigeria-Cameroon Chimpanzees (Pan troglodytes ellioti) on Preuss’s Red Colobus (Procolobus preussi) in the Ebo Forest, Cameroon

We describe the first observation of a predation attempt by Nigerian-Cameroon chimpanzees (Pan troglodytes ellioti) on Preuss’s red colobus (Procolobus preussi) in the Ebo forest, Cameroon. The activity, which was observed for 15 min, primarily involved 1 chimpanzee and 1 red colobus individual, with a further 2 chimpanzees observing the event. Although the behaviour was interrupted when we were detected by the chimpanzees, we believe that this is the first recorded observation of hunting behaviour in Nigeria-Cameroon chimpanzees.