Trophic relations in a community of African rainforest carnivores

Abstract

The factors that promote ecological separation among closely related sympatric carnivores in tropical forests are poorly understood due to a paucity of field studies. Here, we report on community-wide food resource utilization patterns among eight co-existing carnivores in the Dzanga-Sangha Reserve, Central African Republic, based on a collection of 666 scats that were identified using a combination of methods, including thin-layer chromatography. Members of the assemblage took advantage of the diverse array of food resources characteristic of tropical forest habitats by adopting a variety of feeding strategies, such as carnivory, insectivory, frugivory, and piscivory. Broad-scale dietary separation was evident among most pairs, with only 6 of 21 exhibiting food niche overlaps that exceeded 50%. The marsh mongoose (Atilax paludinosus) and African civet (Civettictis civetta) were the most specialized with respect to food habits. Highest trophic overlaps were evident between the most carnivorous [leopard (Panthera pardus) and golden cat (Profelis aurata)] or insectivorous [mongooses (Herpestes naso and Bdeogale nigripes)] species. Unlike other animal groups, species richness of the food resource base was not a key factor structuring this rainforest community. Stronger roles were instead played by the size diversity and abundance of mammalian prey, and the perhaps superabundant or at least highly renewable nature of insects. Ecological separation was further facilitated by some segregation along the spatial (habitat) and temporal (activity) niche dimensions. The average weight of prey taken by leopards was considerably lower than that in other African and Asian sites. Mammals weighing over 20 kg were taken rarely, while use of small (<5 kg) prey was unusually high, signaling either the relatively depauperate base of the former, or high level of abundance and/or profitability of the latter.

Trophic relationships of sympatric small carnivores in fragmented landscapes of southern Brazil: niche overlap and potential for competition

“…We also estimated the relative biomass of each item present in the diet. The percent volume of each prey type in a particular stomach was estimated by eye [following Kruuk and Parish (1981) and Ray and Sunquist (2001)] and scored on a nine-point scale: 0 (absence), 1 ( < 1%), 2 (1-5%), 3 (6-10%), 4 (11-25%), 5 (26-50%), 6 (51-75%), 7 (76-98%), and 8 ( > 98%). For calculations, scores were converted to the midpoint of each percentage interval (1 = 0.5%, 2 = 3%, 3 = 8%, 4 = 18%, 5 = 38%, 6 = 63%, 7 = 87%, 8 = 99%).…”

“…We adopted a similarity of 50% as a cutoff point in order to determine a guild; this is the same value adopted by Fedriani and Travaini (2000), and similar to the value adopted by Zapata et al (2007). We also identified the major axes of dietary variation based on 11 main groups of prey items among carnivore species, using correspondence analysis (following Ray and Sunquist 2001).…”

“…Several studies have indicated that one of the most important features in ecological separation is related to dietary differences (Konecny 1989, Ray and Sunquist 2001, Juarez and Marinho-Filho 2002. These differences may not be specifically associated with how items are consumed, but with what frequency, and with the energy content of each item.…”

Inventorying medium- and large-sized mammals in the African lowland rainforest using camera trapping

“…1). In addition, I referred to published literature reviews of primates (Chapman et al 1999) and carnivores (Ray andSunquist 2001, Laila et al 2013), and to the African Antelope Database (Rod 1999). Lope and Odzala contain savannah areas, whereas IpassaMakokou and Campo-Ma'an comprise continuous evergreen forests.…”

“…substantial research costs for inconspicuous species; White and Edwards 2000) and/or trace surveys (e.g. difficulty in reliable identifications; Tutin et al 1995, Ray and Sunquist 2001, van Vliet et al 2007, it is important to evaluate the practical advantages and disadvantages of camera trappings in this region.…”