Mammal distribution and trends in the threatened Ebo 'intact forest landscape', Cameroon

Intact forest landscapes (IFLs) are globally important for maintaining functional ecosystems. Ebo forest (~1400 km2) in Cameroon is one of the largest remaining IFLs in the Cross-Sanaga-Bioko coastal forest ecoregion and harbours several IUCN Red-Listed threatened mammal species. We evaluated the status, trends, and distribution of mammals ≥ 0.5 kg in the Ebo forest over 12 years using guided recce and camera trap monitoring surveys, as well as local knowledge to inform future land use and conservation planning. Recce monitoring of seven taxa (blue duiker Philantomba monticola, chimpanzee Pan troglodytes, forest elephant Loxodonta cyclotis, putty-nosed monkey Cercopithecus nictitans, medium sized duikers Cephalophus spp., and red river hog Potamochoerus porcus) showed that some are stable or increasing. Indeed, our recent camera trap data confirmed breeding Gorilla gorilla (western gorilla) and elephant. Distribution models for chimpanzees and elephants showed that their populations are concentrated in the centre of the forest, away from human pressure. Some other species, however, including red colobus Piliocolobus preussi, leopard Panthera pardus, African golden cat Caracal aurata, and forest buffalo Syncerus caffer nanus are either close to extirpation or have been extirpated within living memory. We conclude that the Ebo intact forest landscape retains an important mammal community, despite no formal legal protection. Ebo’s future is uncertain, with two commercial logging concessions announced by Cameroon in 2020 and later suspended in response to national and international pressure. It is crucial to maintain Ebo’s integrity to maintain the biodiversity and function of this important part of the Cross-Sanaga-Bioko coastal forest ecoregion

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

Background: The 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. Results: Ecological 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. Conclusions: These 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

Modeling the potential distribution of the threatened Grey-necked Picathartes Picathartes oreas across its entire range

Understanding the distribution and extent of suitable habitats is critical for the conservation of endangered and endemic taxa. Such knowledge is limited for many Central African species, including the rare and globally threatened Grey-necked Picathartes Picathartes oreas, one of only two species in the family Picathartidae endemic to the forests of Central Africa. Despite growing concerns about land-use change resulting in fragmentation and loss of forest cover in the region, neither the extent of suitable habitat nor the potential species’ distribution is well known. We combine 339 (new and historical) occurrence records of Grey-necked Picathartes with environmental variables to model the potential global distribution. We used a Maximum Entropy modelling approach that accounted for sampling bias. Our model suggests that Grey-necked Picathartes distribution is strongly associated with steeper slopes and high levels of forest cover, while bioclimatic, vegetation health, and habitat condition variables were all excluded from the final model. We predicted 17,327 km2 of suitable habitat for the species, of which only 2,490 km2 (14.4%) are within protected areas where conservation designations are strictly enforced. These findings show a smaller global distribution of predicted suitable habitat forthe Grey-necked Picathartes than previously thought. This work provides evidence to inform a revision of the International Union for Conservation of Nature (IUCN) Red List status, and may warrant upgrading the status of the species from “Near Threatened” to “Vulnerable”

Using nonhuman culture in conservation requires careful and concerted action

Discussions of how animal culture can aid the conservation crisis are burgeoning. As scientists and conservationists working to protect endangered species, we call for reflection on how the culture concept may be applied in practice. Here, we discuss both the potential benefits and potential shortcomings of applying the animal culture concept, and propose a set of achievable milestones that will help guide and ensure its effective integration existing conservation frameworks, such as Adaptive Management cycles or Open Standards

Author Correction: Environmental variability supports chimpanzee behavioural diversity

The original version of the Supplementary Information associated with this Article included an incorrect Supplementary Data 1 file, in which three columns (L, M and P) had slightly different variable names from those written in the code. The HTML has been updated to include a corrected version of Supplementary Data 1; the correct version of Supplementary Data 1 can be found as Supplementary Information associated with this Correction.Additional co-authors: Mattia Bessone, Gregory Brazzola, Valentine Ebua Buh, Rebecca Chancellor, Heather Cohen, Charlotte Coupland, Bryan Curran, Emmanuel Danquah, Tobias Deschner, Dervla Dowd, Manasseh Eno-Nku, J. Michael Fay, Annemarie Goedmakers, Anne-Céline Granjon, Josephine Head, Daniela Hedwig, Veerle Hermans, Sorrel Jones, Jessica Junker, Parag Kadam, Mohamed Kambi, Ivonne Kienast, Deo Kujirakwinja, Kevin E. Langergraber, Juan Lapuente, Bradley Larson, Kevin C. Lee, Vera Leinert, Manuel Llana, Sergio Marrocoli, Amelia C. Meier, David Morgan, Emily Neil, Sonia Nicholl, Emmanuelle Normand, Lucy Jayne Ormsby, Liliana Pacheco, Alex Piel, Jodie Preece, Martha M. Robbins, Aaron Rundus, Crickette Sanz, Volker Sommer, Fiona Stewart, Nikki Tagg, Claudio Tennie, Virginie Vergnes, Adam Welsh, Erin G. Wessling, Jacob Willie, Roman M. Wittig, Yisa Ginath Yuh, Klaus Zuberbühler & Hjalmar S. Küh

To conserve African tropical forests, invest in the protection of its most endangered group of monkeys, red colobus

Forest loss and overhunting are eroding African tropical biodiversity and threatening local human food security, livelihoods, and health. Emblematic of this ecological crisis is Africa's most endangered group of monkeys, the red colobus (genus Piliocolobus). All 17 species, found in forests from Senegal in the west to the Zanzibar archipelago in the east, are threatened with extinction. Red colobus are among the most vulnerable mammals to gun hunting, typically disappearing from heavily hunted forests before most other large-bodied animals. Despite their conservation status, they are rarely a focus of conservation attention and continue to be understudied. However, red colobus can act as critical barometers of forest health and serve as flagships for catalyzing broader African tropical forest conservation efforts. We offer a plan for conservation of red colobus and their habitats and discuss conservation and policy implications.Additional authors: Deo Kujirakwinja, Barney Long, W. Scott McGraw, Russell A. Mittermeier, Thomas T. Struhsake

Author Correction: Environmental variability supports chimpanzee behavioural diversity

A Correction to this paper has been published: https://doi.org/10.1038/s41467-021-21010-z

Classifying chimpanzee (Pan troglodytes) landscapes across large scale environmental gradients in Africa

Primates are sometimes categorized in terms of their habitat. Although such categorization can be over-simplistic, there are scientific benefits from the clarity and consistency that habitat categorization can bring. Chimpanzees (Pan troglodytes) inhabit various environments, but researchers often refer to ‘forest’ or ‘savanna’ chimpanzees. Despite the wide use of this forest-savanna distinction, clear definitions of these landscapes for chimpanzees, based on environmental variables at study sites or determined in relation to existing bioclimatic classifications, are lacking. The robustness of the forest-savanna distinction thus remains to be assessed. We review 43 chimpanzee study sites to assess how the landscape classifications of researchers fit with the environmental characteristics of study sites and with three bioclimatic classifications. We use scatterplots and Principal Components 15 Analysis to assess the distribution of chimpanzee field sites along gradients of environmental 16 variables (temperature, rainfall, precipitation seasonality, forest cover and satellite-derived 17 Hansen tree cover). This revealed an environmental continuum of chimpanzee study sites 18 from savanna to dense forest, with a rarely acknowledged forest mosaic category in between, 19 but with no natural separation into these three classes and inconsistencies with the bioclimatic 20 classifications assessed. The current forest–savanna dichotomy therefore masks a progression 21 of environmental adaptation for chimpanzees, and we propose that recognizing an additional, 22 intermediate ‘forest mosaic’ category is more meaningful than focusing on the ends of this 23 environmental gradient only. Future studies should acknowledge this habitat continuum, place their study sites on the forest–savanna gradient, and include detailed environmental data to support further attempts at quantification

Environmental variability supports chimpanzee behavioural diversity.

Funder: Max-Planck-Gesellschaft (Max Planck Society); doi: https://doi.org/10.13039/501100004189Funder: Heinz L. Krekeler FoundationLarge brains and behavioural innovation are positively correlated, species-specific traits, associated with the behavioural flexibility animals need for adapting to seasonal and unpredictable habitats. Similar ecological challenges would have been important drivers throughout human evolution. However, studies examining the influence of environmental variability on within-species behavioural diversity are lacking despite the critical assumption that population diversification precedes genetic divergence and speciation. Here, using a dataset of 144 wild chimpanzee (Pan troglodytes) communities, we show that chimpanzees exhibit greater behavioural diversity in environments with more variability - in both recent and historical timescales. Notably, distance from Pleistocene forest refugia is associated with the presence of a larger number of behavioural traits, including both tool and non-tool use behaviours. Since more than half of the behaviours investigated are also likely to be cultural, we suggest that environmental variability was a critical evolutionary force promoting the behavioural, as well as cultural diversification of great apes