This article provides the first data on amphibian diversity in the Yoko Forest Reserve, located in the Democratic Republic of the Congo. During twenty-four field sampling campaigns organized over a period of twelve months, amphibians were collected from nocturnal surveys supported by three techniques: visual spotting using a headlamp, systematic searching of habitats and acoustic hearing of vocalizations. A total of 5707 amphibians in 10 families, 17 genera and 33 species were recorded throughout the study area. The Hyperoliidae and Arthroleptidae families were the most diverse, with Amnirana albolabris (Ranidae) the most abundant species, followed by Phrynobatrachus auritus (Phrynobatrachidae). By contrast, Afrixalus quadrivittatus, A. equatorialis, Arthroleptis tuberosus, A. variabilis, Cryptothylax greshoffi, Hyperolius langi, H. ocellatus, H. parallelus, Hyperolius sp., Hoplobatrachus occipitalis, Kassina maculosa, Leptopelis calcaratus, Nectophryne batesii, Phrynobatrachus perpalmatus, Sclerophrys gracilipes and S. gutturalis were less frequent. For the first time, Amietia nutti and Kassina maculosa have been reported in Congolese forests. Amphibian species known from the YFRE are widely distributed in Central African forests, and particularly in the Democratic Republic of the Congo, where A. equatorialis, H. langi, H. parallelus and Ptychadena christyi are endemic.

Anthropogenic disturbance of natural environments has negative impacts on biodiversity. Amphibians are especially sensitive to deforestation, and there is a high rate of this phenomenon in the Democratic Republic of the Congo. We studied the effects of this modification of forest ecosystems on the diversity of amphibians in the Yoko Forest Reserve. During twenty-four field sampling campaigns organized over a period of twelve months, amphibians were collected from nocturnal surveys supported by three techniques: visual spotting using a headlamp, systematic searching of habitats and acoustic hearing of vocalizations. Twelve sampling sites were chosen, and three habitats were explored at each site. Of these three habitats, one is the undisturbed habitat (primary forest), and two are disturbed habitats (fallow and field). Amphibian abundance, species richness, diversity, evenness and density were compared between these two types of habitat. A total of 4443 amphibians in 10 families, 17 genera and 33 species were recorded throughout the study area. Abundance, species richness and relative density were significantly higher in non-disturbed habitats than in disturbed habitats. On the other hand, primary forest is less diverse than fallow, but not significantly. It is, however, significantly more diverse than the field. The undisturbed habitat is also characterized by lower evenness than the disturbed habitats, with which it shares low similarities. The species Amnirana albolabris, Phrynobatrachus auritus, Leptopelis notatus, Leptopelis millsoni, Xenopus pygmaeus, Hyperolius platyceps, Leptopelis calcaratus, Leptopelis christyi, Leptopelis ocellatus, Arthroleptis tuberosus, Ptychadena perreti, Amietia nutti, Arthroleptis variabilis, Cardioglossa leucomystax, Phrynobatrachus perpalmatus and Chiromantis rufescens were recognized, in order of importance, as primary forest indicators according to the results of this study. All these differences between the two habitat statuses (undisturbed and disturbed) confirm the negative effects of natural habitat alteration on forest amphibians.

Edges provide valuable insight into the effects of landscape structure on forest ecosystems and faunal distribution. This study assessed edge effects on amphibian diversity in the Yoko Forest Reserve, Democratic Republic of the Congo. Over twelve months (from December 2020 to November 2021), amphibians were surveyed during 24 nocturnal field campaigns using visual detection, habitat searches, and acoustic hearing of vocalizations. Twelve sites were sampled, each including five habitats: primary forest, fallow, field, and two edge types (primary forest-fallow and primary forest-field). Amphibian abundance, species richness, diversity, evenness, and relative density were compared between each edge and its adjacent habitats. A total of 5516 individuals (33 species, 17 genera, 10 families) were recorded. Edges had lower abundance, richness and density than the primary forest but higher than adjacent disturbed habitats. The forest-fallow edge maintained similar diversity to the primary forest, while the forest-field edge showed significantly lower diversity. Forest evenness was lower than at both edges. Several species, including Hylarana albolabris, Leptopelis calcaratus, L. christyi, L. millsoni, L. notatus, L. ocellatus and Sclerophrys pusilla showed intermediate abundances at the primary forest-fallow edge. Similarly, Afrixalus osorioi and Ptychadena mascareniensis showed intermediate abundances in the primary forest-field edge. Scelophrys gracilipes and S. pusilla showed a positive preference for the primary forest-field edge. Afrixalus osorioi, A. quadrivittatus, Chiromantis rufescens, Hylambates verrucosus, Hyperolius sp., H. langi, H. ocellatus, Leptopelis calcaratus, Ptychadena christyi, P. mascareniensis, P. perreti, Sclerophrys gutturalis and S. gracilipes showed a positive preference for the primary forest-fallow edge. Among these species, Chiromantis rufescens and P. mascareniensis showed a moderate but significant preference for this edge, enabling them to be considered specialists of this habitat. These results confirm the structuring role of edges in forest amphibian population’s dynamics.