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Paleoclimate reconstructions have enhanced our understanding of how past climates have shaped present-day biodiversity. We hypothesize that the geographic extent of Pleistocene forest refugia and suitable habitat fluctuated significantly in time during the late Quaternary for chimpanzees (Pan troglodytes). Using bioclimatic variables representing monthly temperature and precipitation estimates, past human population density data, and an extensive database of georeferenced presence points, we built a model of changing habitat suitability for chimpanzees at fine spatio-temporal scales dating back to the Last Interglacial (120,000 BP). Our models cover a spatial resolution of 0.0467 degrees (approximately 5.19 km(2) grid cells) and a temporal resolution of between 1000 and 4000 years. Using our model, we mapped habitat stability over time using three approaches, comparing our modeled stability estimates to existing knowledge of Afrotropical refugia, as well as contemporary patterns of major keystone tropical food resources used by chimpanzees, figs (Moraceae), and palms (Arecacae). Results show habitat stability congruent with known glacial refugia across Africa, suggesting their extents may have been underestimated for chimpanzees, with potentially up to approximately 60,000 km(2) of previously unrecognized glacial refugia. The refugia we highlight coincide with higher species richness for figs and palms. Our results provide spatio-temporally explicit insights into the role of refugia across the chimpanzee range, forming the empirical foundation for developing and testing hypotheses about behavioral, ecological, and genetic diversity with additional data. This methodology can be applied to other species and geographic areas when sufficient data are available.

Aim: Modelling African great ape distribution has until now focused on current or past conditions, while future scenarios remain scarcely explored. Using an ensemble forecasting approach, we predicted changes in taxon-specific distribution under future scenarios of climate, land use and human populations for (1) areas outside protected areas (PAs) only (assuming complete management effectiveness of PAs), (2) the entire study region and (3) interspecies range overlap. Location: Tropical Africa. Methods: We compiled occurrence data (n = 5,203) on African apes from the IUCN A.P.E.S. database and extracted relevant climate-, habitat- and human-related predictors representing current and future (2050) conditions to predict taxon-specific range change under a best- and a worst-case scenario, using ensemble forecasting. Results: The predictive performance of the models varied across taxa. Synergistic interactions between predictors are shaping African ape distribution, particularly human-related variables. On average across taxa, a range decline of 50% is expected outside PAs under the best scenario if no dispersal occurs (61% in worst scenario). Otherwise, an 85% range reduction is predicted to occur across study regions (94% worst). However, range gains are predicted outside PAs if dispersal occurs (52% best, 21% worst), with a slight increase in gains expected across study regions (66% best, 24% worst). Moreover, more than half of range losses and gains are predicted to occur outside PAs where interspecific ranges overlap. Main Conclusions: Massive range decline is expected by 2050, but range gain is uncertain as African apes will not be able to occupy these new areas immediately due to their limited dispersal capacity, migration lag and ecological constraints. Given that most future range changes are predicted outside PAs, Africa's current PA network is likely to be insufficient for preserving suitable habitats and maintaining connected ape populations. Thus, conservation planners urgently need to integrate land use planning and climate change mitigation measures at all decision-making levels both in range countries and abroad.

Funder: Max-Planck-Gesellschaft (Max Planck Society); doi: https://doi.org/10.13039/501100004189, Funder: Max Planck Society Innovation Fund Heinz L. Krekeler Foundation, Much like humans, chimpanzees occupy diverse habitats and exhibit extensive behavioural variability. However, chimpanzees are recognized as a discontinuous species, with four subspecies separated by historical geographic barriers. Nevertheless, their range-wide degree of genetic connectivity remains poorly resolved, mainly due to sampling limitations. By analyzing a geographically comprehensive sample set amplified at microsatellite markers that inform recent population history, we found that isolation by distance explains most of the range-wide genetic structure of chimpanzees. Furthermore, we did not identify spatial discontinuities corresponding with the recognized subspecies, suggesting that some of the subspecies-delineating geographic barriers were recently permeable to gene flow. Substantial range-wide genetic connectivity is consistent with the hypothesis that behavioural flexibility is a salient driver of chimpanzee responses to changing environmental conditions. Finally, our observation of strong local differentiation associated with recent anthropogenic pressures portends future loss of critical genetic diversity if habitat fragmentation and population isolation continue unabated.

Large 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.

Despite the large body of literature on ape conservation, much of the data needed for evidence‐based conservation decision‐making is still not readily accessible and standardized, rendering cross‐site comparison difficult. To support knowledge synthesis and to complement the IUCN SSC Ape Populations, Environments and Surveys database, we created the A.P.E.S. Wiki (https://apeswiki.eva.mpg.de), an open‐access platform providing site‐level information on ape conservation status and context. The aim of this Wiki is to provide information and data about geographical ape locations, to curate information on individuals and organizations active in ape research and conservation, and to act as a tool to support collaboration between conservation practitioners, scientists, and other stakeholders. To illustrate the process and benefits of knowledge synthesis, we used the momentum of the update of the conservation action plan for western chimpanzees (Pan troglodytes verus) and began with this critically endangered taxon. First, we gathered information on 59 sites in West Africa from scientific publications, reports, and online sources. Information was compiled in a standardized format and can thus be summarized using a web scraping approach. We then asked experts working at those sites to review and complement the information (20 sites have been reviewed to date). We demonstrate the utility of the information available through the Wiki, for example, for studying species distribution. Importantly, as an open‐access platform and based on the well‐known wiki layout, the A.P.E.S. Wiki can contribute to direct and interactive information sharing and promote the efforts invested by the ape research and conservation community. The Section on Great Apes and the Section on Small Apes of the IUCN SSC Primate Specialist Group will guide and support the expansion of the platform to all small and great ape taxa. Similar collaborative efforts can contribute to extending knowledge synthesis to all nonhuman primate species.

AimModelling African great ape distribution has until now focused on current or past conditions, whilst future scenarios remain scarcely explored. Using an ensemble forecasting approach, we predicted changes in taxon-specific distribution under future scenarios of climate, land-use and human population changes.LocationSub-Saharan AfricaMethodsWe compiled occurrence data on African ape populations from the IUCN A.P.E.S. database and extracted relevant human-, climate- and habitat-related predictors representing current and future (2050) conditions to predict taxon-specific distribution under a best- and a worst-case scenario, using ensemble forecasting. Given the large effect on model predictions, we further tested algorithm sensitivity by considering default and non-default modelling options. The latter included interactions between predictors and polynomial terms in correlative algorithms.ResultsThe future distributions of gorilla and bonobo populations are likely to be directly determined by climate-related variables. In contrast, future chimpanzee distribution is influenced mostly by anthropogenic variables. Both our modelling approaches produced similar model accuracy, although a slight difference in the magnitude of range change was found for Gorilla beringei beringei, G. gorilla diehli, and Pan troglodytes schweinfurthii. On average, a decline of 50% of the geographic range (non-default; or 55% default) is expected under the best scenario if no dispersal occurs (57% non-default or 58% default in worst scenario). However, new areas of suitable habitat are predicted to become available for most taxa if dispersal occurs (81% or 103% best, 93% or 91% worst, non-default and default, respectively), except for G. b. beringei.Main ConclusionsDespite the uncertainty in predicting the precise proportion of suitable habitat by 2050, both modelling approaches predict large range losses for all African apes. Thus, conservation planners urgently need to integrate land-use planning and simultaneously support conservation and climate change mitigation measures at all decision-making levels both in range countries and abroad.

AimPaleoclimate reconstructions have enhanced our understanding of how past climates may have shaped present-day biodiversity. We hypothesize that habitat stability in historical Afrotropical refugia played a major role in the habitat suitability and persistence of chimpanzees (Pan troglodytes) during the late Quaternary. We aimed to build a dynamic model of changing habitat suitability for chimpanzees at fine spatio-temporal scales to provide a new resource for understanding their ecology, behaviour and evolution.LocationAfrotropics.TaxonChimpanzee (Pan troglodytes), including all four subspecies (P. t. verus, P. t. ellioti, P. t. troglodytes, P. t. schweinfurthii).MethodsWe used downscaled bioclimatic variables representing monthly temperature and precipitation estimates, historical human population density data and an extensive database of georeferenced presence points to infer chimpanzee habitat suitability at 62 paleoclimatic time periods across the Afrotropics based on ensemble species distribution models. We mapped habitat stability over time using an approach that accounts for dispersal between time periods, and compared our modelled stability estimates to existing knowledge of Afrotropical refugia. Our models cover a spatial resolution of 0.0467 degrees (approximately 5.19 km2 grid cells) and a temporal resolution of every 1,000–4,000 years dating back to the Last Interglacial (120,000 BP).ResultsOur results show high habitat stability concordant with known historical forest refugia across Africa, but suggest that their extents are underestimated for chimpanzees. We provide the first fine-grained dynamic map of historical chimpanzee habitat suitability since the Last Interglacial which is suspected to have influenced a number of ecological-evolutionary processes, such as the emergence of complex patterns of behavioural and genetic diversity.Main ConclusionsWe provide a novel resource that can be used to reveal spatio-temporally explicit insights into the role of refugia in determining chimpanzee behavioural, ecological and genetic diversity. This methodology can be applied to other taxonomic groups and geographic areas where sufficient data are available.

Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities. Using data and samples collected over three decades, we show that rainforest anthrax is a persistent and widespread cause of death for a broad range of mammalian hosts. We predict that this pathogen will accelerate the decline and possibly result in the extirpation of local chimpanzee (Pan troglodytes verus) populations. We present the epidemiology of a cryptic pathogen and show that its presence has important implications for conservation.

Even though information on global biodiversity trends becomes increasingly available, large taxonomic and spatial data gaps persist at the scale relevant to planning conservation interventions. This is because data collectors are hesitant to share data with global repositories due to workload, lack of incentives, and perceived risk of losing intellectual property rights. In contrast, due to greater conceptual and methodological proximity, taxon-specific database initiatives can provide more direct benefits to data collectors through research collaborations and shared authorship. The IUCN SSC Ape Populations, Environments and Surveys (A.P.E.S.) database was created in 2005 as a repository for data on great apes and other primate taxa. It aims to acquire field survey data and make different types of data accessible, and provide up-to-date species status information. To support the current update of the conservation action plan for western chimpanzees (Pan troglodytes verus) we compiled field surveys for this taxon from IUCN SSC A.P.E.S., 75% of which were unpublished. We used spatial modeling to infer total population size, range-wide density distribution, population connectivity and landscape-scale metrics. We estimated a total abundance of 52 800 (95% CI 17 577–96 564) western chimpanzees, of which only 17% occurred in national parks. We also found that 10% of chimpanzees live within 25 km of four multi-national ‘development corridors’ currently planned for West Africa. These large infrastructure projects aim to promote economic integration and agriculture expansion, but are likely to cause further habitat loss and reduce population connectivity. We close by demonstrating the wealth of conservation-relevant information derivable from a taxon-specific database like IUCN SSC A.P.E.S. and propose that a network of many more such databases could be created to provide the essential information to conservation that can neither be supplied by one-off projects nor by global repositories, and thus are highly complementary to existing initiatives.

Significance CD4 is known to have evolved rapidly in primates, but the reason for this diversification is unknown. Here, we show that polymorphisms in the simian immunodeficiency virus (SIV) envelope (Env) binding domain of the CD4 receptor modulate the susceptibility of chimpanzee CD4+ T cells to SIV infection by interfering with Env–CD4 interactions required for viral entry. Both amino acid substitutions and N-linked glycosylation sites in the D1 domain blocked Env-mediated entry of a number of SIVs, including viruses that infect primates on which chimpanzees prey. These data identify steric hindrance between cell entry receptor-encoded and virus surface protein-encoded glycans as a mechanism of antiviral protection and suggest that selection pressures by primate lentiviruses, both extant and extinct, have shaped the evolution of chimpanzee CD4., Human and simian immunodeficiency viruses (HIV/SIVs) use CD4 as the primary receptor to enter target cells. Here, we show that the chimpanzee CD4 is highly polymorphic, with nine coding variants present in wild populations, and that this diversity interferes with SIV envelope (Env)–CD4 interactions. Testing the replication fitness of SIVcpz strains in CD4+ T cells from captive chimpanzees, we found that certain viruses were unable to infect cells from certain hosts. These differences were recapitulated in CD4 transfection assays, which revealed a strong association between CD4 genotypes and SIVcpz infection phenotypes. The most striking differences were observed for three substitutions (Q25R, Q40R, and P68T), with P68T generating a second N-linked glycosylation site (N66) in addition to an invariant N32 encoded by all chimpanzee CD4 alleles. In silico modeling and site-directed mutagenesis identified charged residues at the CD4–Env interface and clashes between CD4- and Env-encoded glycans as mechanisms of inhibition. CD4 polymorphisms also reduced Env-mediated cell entry of monkey SIVs, which was dependent on at least one D1 domain glycan. CD4 allele frequencies varied among wild chimpanzees, with high diversity in all but the western subspecies, which appeared to have undergone a selective sweep. One allele was associated with lower SIVcpz prevalence rates in the wild. These results indicate that substitutions in the D1 domain of the chimpanzee CD4 can prevent SIV cell entry. Although some SIVcpz strains have adapted to utilize these variants, CD4 diversity is maintained, protecting chimpanzees against infection with SIVcpz and other SIVs to which they are exposed.

Funding: Generous funding for the Pan African Programme was provided by the Max Planck Society, Max Planck Society Innovation Fund, Krekeler Foundation, Robert Bosch Foundation, Chimbo Foundation and UCSD-SALK Institute Center for Academic Research and Training in Anthropogeny (CARTA). Chimpanzees possess a large number of behavioral and cultural traits among non-human species. The ‘disturbance hypothesis’ predicts that human impact depletes resources and disrupts social learning processes necessary for behavioral and cultural transmission. We used an unprecedented data set 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. Postprint

Objectives – We investigated occurrences and patterns of terrestrial nocturnal activity in wild chimpanzees (Pan troglodytes) and modelled the influence of various ecological predictors on nocturnal activity. Methods – Data were extracted from terrestrial camera-trap footage and ecological surveys from 22 chimpanzee study sites participating in the Pan African Programme: The Cultured Chimpanzee. We described videos demonstrating nocturnal activity, and we tested the effects of the percentage of forest, abundance of predators (lions, leopards and hyenas), abundance of large mammals (buffalos and elephants), average daily temperature, rainfall, human activity, and percent illumination on the probability of nocturnal activity. Results – We found terrestrial nocturnal activity to occur at 18 of the 22 study sites, at an overall average proportion of 1.80% of total chimpanzee activity, and to occur during all hours of the night, but more frequently during twilight hours. We found a higher probability of nocturnal activity with lower levels of human activity, higher average daily temperature, and at sites with a larger percentage of forest. We found no effect of the abundance of predators and large mammals, rainfall, or moon illumination. Discussion – Chimpanzee terrestrial nocturnal activity appears widespread yet infrequent, which suggests a consolidated sleeping pattern. Nocturnal activity may be driven by the stress of high daily temperatures and may be enabled at low levels of human activity. Human activity may exert a relatively greater influence on chimpanzee nocturnal behavior than predator presence. We suggest that chimpanzee nocturnal activity is flexible, enabling them to respond to changing environmental factors.

The Common Agricultural Policy of the European Community has given rise to serious problems: a structural surplus of various agricultural products and a high level of environmental pollution combined with degradation of natural resources both in the European Community and in Third World countries. Different approaches to solve these problems are under discussion at the moment. Each of these solutions has specific ecological consequences. These different approaches are reviewed and evaluated for ecological perspectives.

Cross-breeding experiments between members of the Gammarus pulex-group were carried out using the following species: (1) Gammarus fossarmn Koch, 1836, originating either from northern or from south-eastern France; (2) G. cf. fossarum, collected in the French Pyrenees; (3) G. wautieri Roux, 1967 from the French Alps; (4) G. gauthieri (S. Karaman, 1935) collected both in Spain and in Morocco. G. fossarum, G. wautieri and G. gauthieri are three distinct species. The geographical distribution of G. cf. fossarum and its systematical position are briefly discussed.

A redescription of Gammarus fossarum Koch, 1835, is given, together with some notes on the variability in morphological characters of this species, both within one population and in different populations. It is proved through crosses that five morphologically different populations all belong to the same species, G. fossarum. The geographic variation of the various characters is discussed.

The vitellin content of pike blood was measured by immuno-electrophoretic methods. To get an impression of the fecundity of the Dutch pike, the egg size, number of eggs, protein content of the plasma and condition of the animal were determined. A correlation was found between the vitellin content of the blood of the pike and their maturation stage. Data on the fecundity of Dutch pike showed that their fecundity was normal.

The authors would like to thank the Max Planck Society and Krekeler Foundation for generous funding of the Pan African Programme. 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. Publisher PDF