Development and characterization of microsatellite markers in the African timber tree species Cylicodiscus gabunensis (Fabaceae).

BACKGROUND: Cylicodiscus gabunensis (Fabaceae) or 'Okan' is a Central African multipurpose timber species that is used for heavy construction and traditional medicine. Despite being currently heavily exploited, the species shows a low population density and a natural regeneration deficit in dense forest. METHODS AND RESULTS: We aimed to characterize polymorphic microsatellite markers that can be used to study patterns of genetic structure and gene flow (mating system, pollen and seed dispersal and inbreeding depression) and ultimately, help to develop sustainable forest management practices. We developed 24 polymorphic markers that can be amplified in three PCR multiplexes that were tested in 647 individuals of C. gabunensis from three populations. The number of alleles ranged from 4 to 27 and the average observed and expected heterozygosity across loci and populations were Ho = 0.585 (0.081-0.936) and He = 0.510 (0.076-0.914), respectively. CONCLUSIONS: This set of markers is a useful tool for exploring intra-specific diversity, genetic structure and gene flow of C. gabunensis.

Seed dispersal by proboscis monkeys: the case of Nauclea spp.

Frugivorous vertebrates such as primates are important dispersal agents in tropical forests, although the role of folivorous colobines is generally not considered. However, recent studies reported seed dispersal by endo- and epizoochory in colobine primates, including the proboscis monkey (Nasalis larvatus), suggesting that the role colobines play in seed dispersal might have been underestimated. In the Lower Kinabatangan Floodplain in Sabah, Malaysian Borneo, we investigated whether seeds were still able to germinate after being ingested by proboscis monkeys. Faecal samples (n = 201) from proboscis monkeys were collected between 2015 and 2017. Intact seeds belonging to eight plant species were found in 77% of the faecal samples. Nauclea spp. were the most abundant plant species, accounting for 98% of all intact seeds. This study is the first to conduct germination trials on seeds defecated by proboscis monkeys. Higher germination success was recorded in ingested Nauclea spp. seeds than in control seeds, from both ripe and unripe Nauclea orientalis fruits (P < 0.001). Therefore, we suggest that proboscis monkeys play a role in seed dispersal by enhancing the germination success of defecated seeds for at least some plant species. Similar to other colobines, although proboscis monkeys may provide a lower contribution to seed dispersal (low seed diversity over short distances) than other sympatric frugivores, this study emphasises that proboscis monkeys do contribute to the dispersal of intact seeds, such as Nauclea spp., in potentially suitable riverine habitats.