Comparative study of the mammalian community of the core zone and the community zone of the National Park of Lobeke (Cameroon) in terms of specific richness and composition by camera traps inventory

Abstract

In the current context of the sixth mass extinction, the conservation of large mammalian fauna, particularly threatened in Central Africa, is an important issue. From this perspective, knowledge of the animal communities present is essential in order to ensure management measures adapted to the condition of the fauna. To this end, wildlife inventories using camera traps have become a key technique. Their development, following the development of related technologies and software, allows to improve the quality of the inventories by their low-intrusive aspect and their day and night operation. In this context, this study compares two inventories of terrestrial and semi-terrestrial mammals species conducted by camera traps in the National Park of Lobeke in Cameroon. A first grid of camera traps was set up in the community zone of the park in 2021 and this work focused on the implementation of the second grid in the non-community zone, or core zone, and on the comparison of the results of the two inventories. The main objective of this work is to characterize the differences between these two mammalian communities in terms of species richness and composition. The two grids were composed of 40 camera traps and were following the recommendations of the international TEAM protocol. The camera traps were placed systematically with a density of 1 trap per 2 km². First, a pre-processing of the data was done in two steps. The first step was to review all video captures to identify the species and species complexes present and their numbers. The second step was to clean the dataset to consider only independent events per species, i.e., one event every 30 minutes per species, considering the maximum number of animals, detected in one video, in this interval in case of a group. In a second step, various statistical analyses were performed in order to compare the two communities. First, the species richness was studied in the form of a list of species and an accumulation curve of the number of species according to the sampling effort. Secondly, the study of the relative abundance index (RAI) by species allowed us to identify the most common species present (top 5 for each of the two inventories) and to compare the detection rates of the different species within the two areas. Thirdly, a non-metric multidimensional scaling was performed based on the dissimilarity matrix using the Bray-Curtis index in order to observe the differences in the compositions of the two communities. The analyses conducted showed a higher species richness in the community zone and generally higher RAI, yet they have relatively similar animal communities in terms of composition. A higher poaching pressure in the core zone compared to the community zone could explain these differences.