PhD Dissertation:

Sylvie Gisèle DJOSSOU DJEGO (2013). Occurrence’s areas and eco-ethology of colobus monkeys (Colobus vellerosus and Procolobus verus) in Benin. Ecole Doctorale Pluridisciplinaire, BENIN, 195 pages.

Supervisors : SINSIN Augustin Brice (Bénin) et HUYNEN Marie-Claude (Belgique)

Abstract: In Benin, high anthropic pressure lead to habitats disturbances, some species of primates became vulnerable, even threatened, as this is the case of colobines. Thus, the problem of conservation of wild fauna, in particular that of the primates, became alarming. The main objective of the study is to determine the biogeographic’s characteristics and behavioural ecology of Colobus vellerosus andProcolobus verus in Benin.  We used a diachronic analysis of the extent of occurrence, the forms of threats, activity budget and the habitat use. To gather biogeographic data, we used techniques of investigator, walking survey in forests and visits of local markets where animal’s parts are sold. Moreover, transects lines methods and complete counting in natural environment associated to the results of investigations allowed to appreciate the relative abundance of colobus on various sites of occurrence. Lastly, the observations of monkey groups by methods of scan and ad libitum samplingjoined to quadrant method, allowed to determine activity budget and habitat use. Results showed that extent of occurrence of Colobus vellerosus and Procolobus verus respectively covered 20,506km² and 25,403 km² and currently, ranged in Guinean zone and Guinean-soudanese zone. Several threats are weighing on these monkeys such as the habitats disturbance, deforestation and the poaching.The mean abundances of populations of Colobus vellerosus and Procolobus verus in Benin which were estimated respectively to 543 and 574 individuals, are low and distributed on several sites of occurrence. In Lama Protected Forest, the encounter rate of Colobus vellerosus was 0.60 detection/km versus 0.11detection/km for Procolobus verus and reached 0.49 detection/km in Domè Community Forest. Resting, feeding, moving, socializing and others activity took up respectively 56.64%, 26.31%, 13.04%, 3.31% and 0.70% in activity budget of Colobus vellerosus.Concerning the species resources, colobus manifested flexibility in their diet because about thirty species were consumed. Also, sleeping sites showed characteristics of antipredation, concern and were located in proximity of food resources. Finally, it is appropriate to develop strategies and actions in order to reverse the trend of population decline in primates, especially in colobines.

Key words:  Colobus vellerosus, Procolobus verus, biogeography, abundance, threats, habitat use,activity budgets, Benin.