Environmental and anthropogenic effects on the nesting patterns of Nigeria-Cameroon chimpanzees in North-West Cameroon.

Environmental conditions and human activity influence the selection of nest sites by chimpanzees and may have serious conservation implications. We examined the characteristics of nesting trees preferred by chimpanzees, investigated the effect of vegetation composition and topography on nest site locations and seasonality on nesting heights of chimpanzees, and verified the effect of predator occurrence and human activity on the nesting behavior of the Nigeria-Cameroon chimpanzee (Pan troglodytes ellioti) in Kom-Wum Forest Reserve (KWFR) and surrounding unprotected forest in Cameroon. We recorded 923 nests, 502 signs of human activity, and 646 nesting trees along line transects and recces (reconnaissance) for two seasons. We found that chimpanzees constructed more arboreal nests on tall primary trees with high lowest branch height and large diameter at breast height. Moreover, they oriented their nests within trees in the slope direction when the nesting trees were located on slopes. Additionally, the occurrence of chimpanzee nests was positively related to increasing elevation and slope and decreased with distance to primary forest. In contrast, the number of nests increased with distance to secondary forest, open land, and villages, and nesting height was not influenced by seasons. While we recorded no signs of large nocturnal chimpanzee predators at nesting trees, we found signs of hunting activity at nesting locations. Nesting high in trees is likely a way of avoiding hunting, while nest orientation within trees in slope direction shortens escape routes from human hunters. Our findings suggest that chimpanzees select safe trees (tall trees with high lowest branch height) located in nesting areas (primary forest, high elevation, and steep slopes) that are not easily accessible by humans. Therefore, conservation efforts should focus on protecting primary forests at high elevation and steep slopes and reducing human impact.

Nesting Ecology of a Small Montane Population of the Nigerian/Cameroon Chimpanzee (Pan troglodytes ellioti) in Nigeria.

Understanding nest site choice by chimpanzees has implications for ecology, anthropology, and in the collection of census data, yet it remains controversial. Here we provide the first information on environmental factors affecting nest site choice in a montane population of the rare and relatively understudied Nigerian/Cameroon chimpanzee (Pan troglodytes ellioti) in Ngel Nyaki Forest Reserve, Nigeria. The forest is small, isolated, and visited by researchers, community members, and hunters. We also tested the hypothesis that people (researchers) walking along forest trails collecting data on a regular basis since 2005 will have changed nesting behaviour in the vicinity of the trails. Along the trails searched for nests, the chimpanzees used a subset of 35 (28.5%) of all available tree species. The top 5 nest tree species represented 16% of all non-nest tree species. The nest trees were on steeper than average slopes and the trees themselves were shorter and had a smaller DBH (diameter at breast height) than trees without nests. We found no evidence to suggest a change in nesting behaviour along trails compared with off trails; however, the average nest height today is considerably higher than it was in 2004, which may indicate a change in behaviour across the whole forest.

Dietary preferences of a submontane population of the rare Nigerian-Cameroon chimpanzee (Pan troglodytes ellioti) in Ngel Nyaki Forest Reserve, Nigeria.

We investigated the dietary preferences of chimpanzees residing in a Nigerian submontane forest using a combination of fecal analysis, observations of feeding remains, evidence from feeding tools and fruiting phenological data between April 2010 and March 2011. A total of 495 fecal samples were collected in which 52 fruit taxa were identified as having being consumed by chimpanzees, including 22 identified to species level and two identified to genus level. Ficus (seven species) was the most common seed genus identified, occurring in 61.2% of all fecal samples. Based on fecal analysis and phenological data, Ngel Nyaki chimpanzees do not solely consume fruits based on their availability within the habitat; while the proportion of fruit consumed did reflect the relative availability of fruit in the forest for some fruit species, Ficus was a preferred fruit even when scarce. In contrast, the proportion consumed of other fruit species was low relative to the abundance of their fruit available in the forest. Our results from the Rank Preference Index (RPI) suggest that relative preferences in fruit are seasonal. We discuss the role of Ficus in the diet of chimpanzees in Ngel Nyaki Forest Reserve.

Mapping suitable habitat for Nigeria-Cameroon chimpanzees in Kom-Wum Forest Reserve, North-Western Cameroon.

Great apes lose suitable habitats required for their reproduction and survival due to human activities across their distribution range in Africa. Little is known about habitat suitability of the Nigeria-Cameroon chimpanzee [Pan troglodytes ellioti (Matschie, 1914)], particularly for populations inhabiting forest reserves in North-West Cameroon. To address this knowledge gap, we employed a common species distribution model (MaxEnt) to map and predict suitable habitats for the Nigeria-Cameroon chimpanzee in Kom-Wum Forest Reserve, North-West Cameroon, based on environmental factors that potentially affect habitat suitability. We related these environmental factors to a dataset of chimpanzee occurrence points recorded during line transect and reconnaissance (recce) surveys in the forest reserve and surrounding forests.  Up to 91% of the study area is unsuitable for chimpanzees. Suitable habitats only represented 9% of the study area, with a high proportion of highly suitable habitats located outside the forest reserve. Elevation, secondary forests density, distance to villages and primary forests density were the most important predictors of habitat suitability for the Nigeria-Cameroon chimpanzee. The probability of chimpanzee occurrence increased with elevation, secondary forest density and distance from villages and roads. Our study provides evidence that suitable chimpanzee habitat in the reserve is degraded, suggesting that efforts to maintain protected areas are insufficient. The reserve management plan needs to be improved to conserve the remaining suitable habitat and to avoid local extinction of this endangered subspecies.

Adverse Events Following Immunization With Combined vs Concurrent Monovalent Hepatitis A and Typhoid Vaccines in Children.

Combined hepatitis A and typhoid vaccine is available in Australia, but licensed for use from age 16 years; however it is used "off-label" in children. The combined vaccine is well tolerated in children aged 2-16 years and the risk of adverse events is similar to those receiving concurrent monovalent vaccines.

New tools suggest local variation in tool use by a montane community of the rare Nigeria-Cameroon chimpanzee, Pan troglodytes ellioti, in Nigeria.

Regional variations in tool use among chimpanzee subspecies and between populations within the same subspecies can often be explained by ecological constraints, although cultural variation also occurs. In this study we provide data on tool use by a small, recently isolated population of the endangered Nigeria-Cameroon chimpanzee Pan troglodytes ellioti, thus demonstrating regional variation in tool use in this rarely studied subspecies. We found that the Ngel Nyaki chimpanzee community has its own unique tool kit consisting of five different tool types. We describe a tool type that has rarely been observed (ant-digging stick) and a tool type that has never been recorded for this chimpanzee subspecies or in West Central Africa (food pound/grate stone). Our results suggest that there is fine- scale variation in tool use among geographically close communities of P. t. ellioti, and that these variations likely reflect both ecological constraints and cultural variation.