Phytosociological Study of Nyungwe Montane Savannahs

It is uncommon to find savannahs encompassed into tropical montane rainforests. The case of Nyungwe savannahs is one of these particularities and until now no explanation on their origin, structure and dynamics was given. This unprecedented research documented special floristic diversity of montane savannahs of Nyungwe, described the structure of their plant communities to provide data for their sustainable conservation. In this paper origin of these savannahs was discussed. The study was conducted in three sites harbouring five savannahs:Karamba, Nyabitimbo and Muzimu. Eight plant communities (4 in savannah-forest contact zone and other 4 in savannah) were identified with 198 species. Vascular species were distributed in 71 families. Phytogeographic distribution analysis of species showed the predominance of afromontane species (Mo) in sampled savannahs (31%), followed by East African montane species (Mo, EA) with 22% of all species. Montane endemism proved the predominance of ‘relatively restricted endemic species’ identified in 2or3 montane systems (among Kivu-Ruwenzori, ImatongsUsambara, UluguruMlanje, and Ethiopia with 41.1%) followed by ‘afromontane endemic wades’ identified in 4to7 systems representing 39.9%). ‘Local endemic montane species’ represented 31% of all species. Thus, these savannahs are favourable to species coming from almost seven African montane systems. Keywords: Nyungwe, Plant communities, montane savannahs

Human impact erodes chimpanzee behavioral diversity

Chimpanzees possess a large number of behavioral and cultural traits among nonhuman species. The “disturbance hypothesis” predicts that human impact depletes resources and disrupts social learning processes necessary for behavioral and cultural transmission. We used a dataset of 144 chimpanzee communities, with information on 31 behaviors, to show that chimpanzees inhabiting areas with high human impact have a mean probability of occurrence reduced by 88%, across all behaviors, compared to low-impact areas. This behavioral diversity loss was evident irrespective of the grouping or categorization of behaviors. Therefore, human impact may not only be associated with the loss of populations and genetic diversity, but also affects how animals behave. Our results support the view that “culturally significant units” should be integrated into wildlife conservation

Camera trapping reveals trends in forest duiker populations in African National Parks

Bushmeat hunting is widely cited as cause for declines of wildlife populations throughout Africa. Forest duikers (Bovidae, Cephalophinae) are among the most exploited species. Whether current harvest rates imperil duikers is debated because of the difficulty of accurately assessing population trends. To assess population trends, we first reviewed literature for historical duiker population estimates. Second, we used systematic camera-trap monitoring to assess population trends for 15 populations of nine duiker species in six national parks in Central and East Africa. We analysed annual monitoring data using Royle-Nichols heterogeneity-induced occupancy models to estimate abundance/sample point and derive occupancy estimates. Published density estimates indicate that duiker populations declined significantly throughout Africa between 1973 and 2013. There was a wide range of densities depending on species ((Formula presented.) range: 0.26–20.6 km−1) and whether populations were hunted ((Formula presented.) =6.3 km−1) or unhunted ((Formula presented.) = 16.3 km−1). More recent analysis of camera-trap monitoring produced different results. Estimated mean point abundance over time was between 0 and 0.99 individuals/point for four populations, between 1.0 and 1.99 for six populations, and greater than 2.0 for five populations. We observed five populations of duikers with negative trends in point abundances, although only one trend was significant and point abundance estimates for three populations were above 2.0 in the final survey year. Six populations showed positive trends in point abundance (three significant), and the remaining populations displayed no trends. Average occupancy was high (Ψ > 0.60) except for three populations. While literature indicates that historical population declines have occurred, most duiker populations appear relatively healthy in monitored parks. Our results indicate that these parks are effective in protecting most duikers despite hunting pressure. We recommend that systematic, standardized camera-trap monitoring be initiated in other African parks in combination with point-abundance models to objectively assess forest ungulate population trends.</p

Structure of Chimpanzee Gut Microbiomes across Tropical Africa

Understanding variation in host-associated microbial communities is important given the relevance of microbiomes to host physiology and health. Using 560 fecal samples collected from wild chimpanzees (Pan troglodytes) across their range, we assessed how geography, genetics, climate, vegetation, and diet relate to gut microbial community structure (prokaryotes, eukaryotic parasites) at multiple spatial scales. We observed a high degree of regional specificity in the microbiome composition, which was associated with host genetics, available plant foods, and potentially with cultural differences in tool use, which affect diet. Genetic differences drove community composition at large scales, while vegetation and potentially tool use drove within-region differences, likely due to their influence on diet. Unlike industrialized human populations in the United States, where regional differences in the gut microbiome are undetectable, chimpanzee gut microbiomes are far more variable across space, suggesting that technological developments have decoupled humans from their local environments, obscuring regional differences that could have been important during human evolution