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A Comparative Analysis of the Diets of Pelusios Turtles across Africa †
* 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 5 , 1
1  IDECC - Institute for Development, Ecology, Conservation and Cooperation, via G. Tomasi di Lampedusa 33, I-00144 Rome, Italy
2  Department of Wildlife Science, University of Juba, South Sudan P.O.Box 82;
3  AERD – Alliance for Environment and Rural Development; El Hikma Medical Centre Street, Gudele West, Block II. P.O.Box 445, Juba South Sudan
4  Ecolobby, Rome, Italy
5  Wildlife and Biodiversity Conservation unit, Department of Animal and Environmental Biology, Rivers State University, Nkpolu Oroworukwo, Port Harcourt, Nigeria
6  Department of Zoology, University of Uyo, Uyo, Akwa-Ibom State, Nigeria
7  Department of Fisheries, Lagos State University, Ojo, Lagos, Nigeria.
8  Ecologia Applicata Italia s.r.l., Termini Imerese (PA), Italy

Abstract:

Pelusios is an Afrotropical endemic genus of freshwater turtles that have adapted to a variety of habitats, with savannahs and forests being their two main habitat types. Although considered generally carnivorous, these turtles have rarely been subjected to detailed field surveys for determining their quantitative diet. In this paper, by using both literature and original data, we analyse the diet of several Pelusios populations: three P. adansonii populations from South Sudan, one P. nanus from Zambia, seven P. castaneus from Nigeria, Benin and Togo, and four P. niger from Nigeria. All species were omnivorous but with a clear preponderance of the prey items being of animal origin (amphibians, fish, arthropods and anellids). Saturation curves revealed that the diet composition of all the surveyed populations was adequately assessed, and the diversity profiles indicated that all the populations were relatively similar in terms of overall dietary diversity. General Linear Models (GLM) showed a negative effect of vegetation cover on Anura adults consumption by turtles, while showed that the frequencies of Anura tadpoles, fish, reptiles and birds on Pelusios diets increased with the increase of vegetation cover. The GLM model also showed positive effects of individual body size on algae, Bivalvia, reptiles, birds and small mammals consumption by turtles, while underlined that the predation on Arachnida decreased with the increases of turtles body size. All species appeared substantially generalists in terms of their diet composition, although the effects of season (wet versus dry months) were not adequately assessed by our study.

Keywords: Chelonians; Pelomedusidae; Forest; Savannah; Foraging ecology
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