We quantify the impacts of poaching, Ebola, and habitat degradation on western lowland gorillas and central chimpanzees.
Tropical forests are among the most heterogeneous environments on earth, and food resources for many animals are patchy both in time and space. In Africa's equatorial forest, permanent trails created and maintained by forest elephants are conspicuous features. Trails may be several meters wide and continue for tens of kilometers. Speculation on which resources determine the distribution of trails has identified fruit, browse, and mineral deposits as candidates. In this study, the relationships between these habitat variables and elephant trails were investigated. The size of individual trails and the density of the trail system increased dramatically with proximity to mineral deposits. Fruit tree basal area decreased with perpendicular distance from trails, while that of non-fruit trees did not. Fruit tree abundance and basal area were significantly higher on trail intersections than random sites and increased with intersection size. No relationship was found between monocotyledon browse abundance and elephant trail system characteristics. Clumped resources, which are at least partially reliable, provide a high nutritional payback, and are not rapidly depleted and can thus be visited repeatedly, appear to influence permanent trail formation by forest elephants. Permanent trails may allow naive individuals or those with imperfect knowledge to locate and acquire important resources.
Species distributions are influenced by processes occurring at multiple spatial scales. It is therefore insufficient to model species distribution at a single geographic scale, as this does not provide the necessary understanding of determining factors. Instead, multiple approaches are needed, each differing in spatial extent, grain, and research objective. Here, we present the first attempt to model continent‐wide great ape density distribution. We used site‐level estimates of African great ape abundance to (1) identify socioeconomic and environmental factors that drive densities at the continental scale, and (2) predict range‐wide great ape density. We collated great ape abundance estimates from 156 sites and defined 134 pseudo‐absence sites to represent additional absence locations. The latter were based on locations of unsuitable environmental conditions for great apes, and on existing literature. We compiled seven socioeconomic and environmental covariate layers and fitted a generalized linear model to investigate their influence on great ape abundance. We used an Akaike‐weighted average of full and subset models to predict the range‐wide density distribution of African great apes for the year 2015. Great ape densities were lowest where there were high Human Footprint and Gross Domestic Product values; the highest predicted densities were in Central Africa, and the lowest in West Africa. Only 10.7% of the total predicted population was found in the International Union for Conservation of Nature Category I and II protected areas. For 16 out of 20 countries, our estimated abundances were largely in line with those from previous studies. For four countries, Central African Republic, Democratic Republic of the Congo, Liberia, and South Sudan, the estimated populations were excessively high. We propose further improvements to the model to overcome survey and predictor data limitations, which would enable a temporally dynamic approach for monitoring great apes across their range based on key indicators.
The Ogooué Leketi National Park (OLNP) is located within the Batéké-Léconi-Léfini Landscape in the central basin of the Congo River. The Ogooué Leketi Elephant Project (OLEP) area is important for biodiversity conservation from its significant populations of forest species (forest elephant, gorillas, chimpanzees, duikers, monkeys, etc.) combined with savanna species (Grimm’s duiker, side-striped jackal, etc). Elephant sign is highest 0.9/km in the northwest of the Landscape in the border area of the Batéké Plateau National Park in Gabon where a number of mineral-rich clearings, or bais, attract forest elephants and others wildlife. Elephants travel a long distance and consume diverse plants and occasionally animals’ species from one clearing to others throughout the forest. This paper intends to provide an overall preliminary list of plants consumed by forest elephants across their feeding trials. The results of the study points to the fact that, elephants were found to be feeding on 258 different vegetal species and three animal species recorded from twenty-six elephants feeding trials from March 2013 to December 2014 through different methods. Among these plant species, 156 were identified by us and checked by botanists in both the CERVE at Brazzaville and herbarium of Kinshasa University. Elephants were not only eating plants but they were also consuming occasionally some invertebrate such as bees, termites and ants. An analysis of 53 dung piles revealed that 43 dung piles had traces of 26 species of fruit consumed by elephants while 10 dung piles had no traces of fruits. The OLNP is among the least described protected areas in the Republic of Congo, despite its speculated high potential biodiversity. This lack of ground-truth knowledge is attributed to the status of the protected area that Congolese government classified as park in 2018 after 14 years of existence.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.