Claude Mande

Because of their arboreal lifestyle, the diversity and life history of squirrels in low-altitude Afrotropical forests are currently under-researched. Following a 72-day inventory using traditional ...

The taxonomy, distribution, and ecology of sub-Saharan squirrels are poorly documented. This study focuses on the diversity and distribution of rope squirrels (Funisciurus Trouessart, 1880) in the Congo Basin. We compiled the most comprehensive genetic (n = 397 sequences) and morphometric (n = 219 measured skulls) dataset to date, covering much of their geographical and taxonomic range. Analysis of mitochondrial markers recovered 10 MOTUs (Molecular Operational Taxonomic Unit), nuclear markers 2 MOTUs, and morphometrics 5 Operational Taxonomic Units. Integrating this evidence suggests at least six species-level lineages in our dataset: four allopatric taxa related to F. anerythrus; four genetically different taxa (of which two are sympatric species) that resemble F. cf. bayonii; one taxon corresponding to F. pyrropus akka de Winton, 1895; one morphologically distinct taxon that resembles F. cf. congicus; and one unidentified taxon. Their distributional ranges reveal that the Congo and Kasaï Rivers act as major biogeographical barriers, suggesting that they originated by allopatric speciation. Our findings provide a baseline for studying the effects of habitat loss on rope squirrel populations in the Congo Basin and inform research into their role as reservoirs of zoonotic pathogens, including mpox virus.

Context: Volant and non-volant mammals differ in their sensitivity to environmental and anthropogenic pressures, making species traits central to understanding biodiversity erosion. However, the extent to which forest structure predicts faunal composition remains unclear. Aims: We tested how eco-behavioural traits and rainforest structure jointly influence detection and occupancy in mammal assemblages, and whether habitat characteristics reliably explain variation in community composition. Methods: Over 12 months, we combined ground and arboreal camera trapping, bat flight-performance indices, and vegetation measurements in mature lowland forest in the Yangambi Biosphere Reserve, Democratic Republic of the Congo. Single-season multi-species occupancy models were used to estimate variation in detection and occupancy as a function of species traits and habitat characteristics while accounting for imperfect detection. Key results: Detection probability declined sharply with increasing body mass and sociality (Pi = 0.06, β = −39.08), indicating non-random depletion of large-bodied, group-living mammals consistent with trait-mediated filtering under human pressure. Stem density positively affected occupancy (ψ = 0.30, β = 9.06), but this effect was insufficient to offset evidence of defaunation, showing a mismatch between forest condition and assemblage composition. By contrast, bats showed high occupancy (ψ = 0.85) across structural gradients (β = −1.92), whereas detection probability (Pi = 0.162) was unrelated to flight traits, suggesting greater ecological flexibility. Conclusions: Non-volant mammal assemblages were shaped primarily by trait-mediated filtering rather than forest structure alone. By contrast, bats maintained high occupancy across heterogeneous habitats, supporting functional connectivity and showing contrasting responses to environmental change in tropical forests. Implications: Structural metrics alone are insufficient proxies for ecosystem intactness. Integrating species traits with occupancy-based approaches can provide early-warning indicators of biodiversity change and support resilience-based management and restoration of tropical forests.

The full text of this preprint has been withdrawn by the authors since they no longer stand by the findings/conclusions of this work. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

The diversity, taxonomy, distribution and ecology of sub-Saharan tree squirrels remain under-researched. This study aims to elucidate the diversity and distribution of rope squirrels, genus Funisciurus Trouessart 1880, in the Congo Basin. We assembled the most comprehensive genetic and morphometric data set to date, on a significant portion of the geographical and taxonomic range of these squirrels (470 specimens from seven provinces of the Democratic Republic of Congo). We identified six main taxa: a previously undescribed Funisciurus species (here, Fx), three allopatric taxa of Funisciurus anerythrus (Fc, FaRB and FaLB), and two sympatric genetically distinct taxa (FbLB1, FbLB2), potentially belonging to a Funisciurus bayonii species complex. We then mapped their distribution, showing that the Congo and Kasaï Rivers represent significant biogeographical barriers limiting the distribution of Funisciurus species. In addition to providing a baseline for research on the impact of climate change and habitat degradation on the abundance and distribution of rope squirrels, our findings support research on the role of rope squirrel species in the transmission of pathogens of public health importance. Teaser text: We studied the diversity and distribution of rope squirrels, genus Funisciurus Trouessart 1880, in the Congo Basin. By gathering the most comprehensive genetic and morphometric data to date on a significant part of the geographical and taxonomic range of these squirrels (specimens from seven provinces of the Democratic Republic of Congo), we identified six main taxa: one previously undescribed species, three allopatric taxa, and two genetically distinct sympatric taxa. We then mapped their distribution, showing that the Congo and Kasai rivers represent significant biogeographical barriers limiting the distribution of Funisciurus species. These results support research into the role of rope squirrel species in the transmission of pathogens of public health importance. Image for the online table of contents: African rope squirrel Photo credit: Bushnell photo trap set by Pascal Baelo

Altough zoonotic spillover events continue to drive human mpox outbreaks in the Democratic Republic of the Congo (DRC), the wildlife reservoir of mpox virus (MPXV) remains unkown. To address this gap, we screened samples from 2,701 wild mammals, mainly rodents (59.7%), bats (26.4%) and shrews (12.1%). Only six (0.2%) animals were Orthopoxvirus (OPV) PCR positive. Near full-length MPXV sequences were obtained from two squirrels ( Funisciurus anerythrus and Paraxerus sp.) and one soft furred mouse ( Praomys jacksoni ). A novel Taterapox virus was identified in a shrew ( Crocidura cf. denti ). All newly identified MPXV strains belong to clade Ia, but they cluster into different groups or subgroups, despite being collected from geographically close locations, and all are closely related to human MPXV strains from the same regions. Our study provides for the first time clear evidence that MPXV diversity is not restricted to a single rodent host species nor confined to a geographic area. Importantly, MPXV positive Paraxerus and Praomys specimens were sampled close to Kisangani, a city with more than one million habitants, highlighting that spillover events can also occur in or near major cities, with more favorable conditions for interhuman transmissions and potential emergence of new lineages.

The processes involved in acquiring, trading, preparing, and consuming wild meat pose significant risks for the emergence of zoonotic infectious diseases. Several major viral outbreaks have been directly linked to the wild meat supply chain, yet our knowledge of the virome in many mammals involved in this chain remains limited and disproportionately focused on certain mammalian taxa and pathogens. This report presents the findings of a metagenomic viral screening of 99 specimens belonging to 27 wild African mammal species and one domesticated species, all traded for their meat. The study focuses on tissue and swab samples collected from various regions in the Democratic Republic of the Congo and in Brussels, Belgium. A total of fifteen virus strains were detected, belonging to the families Arteriviridae , Retroviridae and Sedoreoviridae (primates), Picobirnaviridae (primates and rodents), Picornaviridae (rodents), Hepadnaviridae (hyrax), Orthoherpesviridae (artiodactylid and carnivore) and Spinareoviridae (carnivore). Several strains were detected in mammalian hosts for the first time, expanding their host range and genetic diversity. Of note is the presence of viruses genetically related to recognised zoonotic pathogens, i.e., human picobirnavirus ( Orthopicobirnavirus hominis ) (primates and rodents), simian foamy viruses ( Simiispumavirus ) (primates), and rotavirus A ( Rotavirus alphagastroenteritidis ) (primates). The presence of these viruses in primates is concerning as non-human primates are phylogenetically closely related to humans, which can facilitate interspecies viral transmission. These findings underscore the high diversity of mammalian viruses and the potential risk of human infection through cross-species transmission during the close interactions with wildlife in the wild meat supply chain.

The wildlife reservoir and spillover mechanisms of the Ebola virus remain elusive despite extensive research efforts in endemic areas. This study employed a One Health approach to examine the virus’ circulation in wildlife and the associated human exposure risks in the Tshuapa province of the Democratic Republic of the Congo. In 2021, we collected 1015 samples from 888 animals, predominantly small mammals, and 380 inhabitants of Inkanamongo village, the site of an Ebola virus disease outbreak in 2014. These samples were screened for evidence of current (RNA) or past (IgG antibodies) Ebola virus infections. We also conducted interviews with 167 individuals in the surrounding districts to assess their interactions with wildlife. While no Ebola virus RNA was detected in the wildlife samples, anti-orthoebolavirus IgG antibodies were found in 13 bats and 38 rodents. Among the human participants, 120 individuals had IgG antibodies against at least one orthoebolavirus antigen, with 12 showing seropositivity for two antigens of the same orthoebolavirus, despite not having a prior Ebola disease diagnosis. Furthermore, over 50% of respondents reported frequent visits to the forest to hunt a variety of wild animals, particularly ungulates and rodents, which could account for occasional viral spillovers. The absence of active Ebola virus circulation in wildlife may reflect seasonal patterns in reservoir ecology, like those observed in bats. Similarly, seasonal human activities, like hunting and foraging, may result in periodic exposure risks. These findings highlight the importance of continuous, multidisciplinary surveillance to monitor changes in seasonal spillover risks.

Prioria balsamifera (Vermoesen) Breteler et Prioria oxyphylla (Harms) Breteler présentent un grand intérêt sur le marché international de bois d’œuvre. Leur attrait commercial a exacerbé leur exploitation. Cet article présente la synthèse bibliographique des connaissances relatives aux traits de vie de ces espèces afin de mettre en évidence les points sur lesquels les nouvelles recherches devront se focaliser. La revue de la littérature montre que peu d’études ont été réalisées sur ces espèces. Cependant, les données disponibles renseignent que P. balsamifera et P. oxyphylla ont une structure spatiale qui varie d’une région à une autre, allant d’une répartition aléatoire à une répartition agrégée, ce qui suggère que les facteurs exogènes auraient une influence sur leur structure. Chez P. balsamifera, les évènements phénologiques (défeuillaison, floraison et fructification) sont annuels et réguliers au niveau de l’espèce, mais irréguliers au niveau de l’individu. Les graines de P. balsamifera, stockées durant deux semaines, n’exigent pas de prétraitement avant semis et présentent une durée de germination pouvant aller jusqu’à 3 mois et un faible pouvoir germinatif (45 %). Bien que sa croissance soit lente en plantation, P. balsamifera présente une meilleure croissance sous un ombrage moyen en forêt dégradée. Le tempérament semi-héliophile est admis pour ces deux espèces. Des investigations sur les facteurs déterminant la structure spatiale de ces espèces, leurs populations reproductrices, les paramètres régulant leurs floraisons, leurs fructifications, la dispersion de leurs diaspores ainsi que la dynamique de leurs cohortes juvéniles doivent être approfondies afin de proposer un modèle approprié pour leur gestion durable.

Assessing how bats respond to habitat attributes requires an integrative approach to reliably predict direct community‐level effects. We focused on hipposiderid and pteropodid bats because of their diverse resource use patterns, body size ranges, and dispersal abilities. We combined an array of bat species‐level characteristics with key forest stand characteristics that may covary with habitat use. Twelve stations were sampled in the Lomami and Yangambi landscapes, Democratic Republic of the Congo. We investigated whether species‐level flight ability of bats and forest stand characteristics can affect bat commuting flights and community‐level estimates of both species detection and habitat occupancy. We captured bats for 108 trap‐nights. Three sampling events (early evening, middle of the night, and early morning) were replicated for each survey night. Hipposiderids showed an early evening flight peak, while flight activity of pteropodids was constant throughout the night, but increased around the middle of the night. Species capture probability decreased with higher wing loading in hipposiderids and was negatively correlated with higher wing aspect ratio in pteropodids. Forest occupancy of hipposiderids increased along the gradient towards waterways, while pteropodid occurrence was not directly linked to measured forest stand variables. This suggests a consequence of habitat patterns at larger spatial scales, which would need clarifying through additional data collection. We discuss these findings in terms of resource‐use strategies of clutter‐tolerant and clutter‐intolerant species. We argue that the occurrence of specific bat species and their habitat use patterns can serve as surrogate measures of ecosystem health.