Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

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.

Cameroon --- National Park of Lobeke --- camera traps --- animal communities --- anthropic pressure --- poaching --- Sciences du vivant > Multidisciplinaire, généralités & autres

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

Considering the importance of mammals in regulating ecological processes in rainforests and the constant expansion of logging in Central Africa, it is essential to study the influence of logging on mammalian communities. This study aims to (i) assess the impact of selective logging on mammalian biodiversity and (ii) compare two methods of surveying elephant populations, one using camera traps and the other using acoustic sensors. The study took place at the SEFAC logging company ; located in the South-East of Cameroon, north of the Lobéké National Park. Wildlife inventories were conducted in two sites with contrasting logging histories, the first having been logged until January 2021 and the second 17 to 45 years ago. In each of these, 12 camera traps and 6 acoustic sensors were set up on a 2 km2 sampling grid. Both devices were left in the field for 7 weeks. A total of 36 mammalian taxa were recorded in both study areas. The vast majority of species had comparable average detection rates between the two sites (p > 0.05). Similarly, the species richness, the species composition and the activity pattern of the most detected species varied only slightly between both areas. Regarding the second objective of this study, passive acoustic monitoring was characterized by a higher detection rate of elephants than camera trap surveys. The false positives produced by the acoustic data processing justify that the detection events of the two surveys do not follow the same trends from a temporal point of view. In clonclusion, this study confirms the high conservation potential of sustainably managed forest concessions. The one studied has a species richness comparable to the one estimated in an adjacent protected area and higher relative abundances of wild bongos, chimpanzees and elephants. This work also shows the quick recovery of mammalian communities after logging as long as hunting activities are contained. By investing in wildlife management and anti-poaching, logging concessions can act as ecological corridors at a landscape scale. Moreover, this study demonstrates the usefulness of acoustic and camera trap surveys in rainforests, it also explains their advantages and disadvantages. Further studies would help identify which type of survey is most appropriate for monitoring elephant populations. Finally, this study highlights the need to develop standardized protocols and efficient automatic detection algorithms to optimize these two survey methods.

Tropical forests --- Defaunation --- Logging concessions --- Wildlife monitoring --- Camera traps --- Passive acoustic monitoring --- Forest elephant --- Forêts tropicales --- Defaunation --- Concessions forestières --- Inventaires faunistiques --- Pièges photographiques --- Inventaires acoustiques --- Eléphant de forêt --- Sciences du vivant > Sciences de l'environnement & écologie