Distribution and relative abundance of forest duikers in Dassioko Sud Forest Reserve (coastal Côte d’Ivoire)
K. A. Yao A B , E. A. Bitty A B , K. B. Kassé A , Y. C. Kouakou B C , K. H. Yaokokoré-Beibro A , S. Gonedelé Bi B D F and W. Scott McGraw EA Laboratoire de Zoologie et Biologie Animale, Université Félix Houphouët Boigny d’Abidjan-Cocody, 22 BP 582 Abidjan 22, Côte d’Ivoire.
B Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire.
C Unité de Formation et de Recherche en Environnement, Université Jean Lorougnon Guédé Daloa, Côte d’Ivoire.
D Laboratoire de Génétique, Université Félix Houphouët Boigny d’Abidjan-Cocody, 22 BP 582, Abidjan 22, Côte d’Ivoire.
E Department of Anthropology, The Ohio State University, Columbus, OH, USA.
F Corresponding author. Email: sery.gonedele@univ-fhb.edu.ci
Wildlife Research 44(8) 660-668 https://doi.org/10.1071/WR17068
Submitted: 14 May 2017 Accepted: 9 December 2017 Published: 26 February 2018
Abstract
Context: Duikers play a vital role in maintaining forest ecosystems, as both seed dispersers and prey. In West Africa, duikers are also an important source of food and income; however, it is likely that some species are now being hunted at unsustainable levels. So as to contribute to duiker conservation, we used line-transect data and additional information on dung and track counts to estimate relative abundance and establish distribution patterns of forest duikers in Côte d’Ivoire’s Dassioko Sud Forest Reserve (DSFR), a poorly known, remnant coastal rainforest. We also collected basic information on hunting pressure.
Methods: Forest duiker counts were made twice per month from July 2013 to March 2014 on six line transects of varying lengths (5.6–6.7 km) and in different regions of the DSFR, representing different habitat types. The number of sightings per kilometre walked, defined as ‘encounter rate’, was used to compute an index of relative abundance. We recorded all evidence of poachers and used these data to generate a poaching index (# poaching signs per kilometre) for different habitat types.
Key results: The DSFR has lost three of seven total forest duiker species and populations of the four remaining species are declining. Encounter rates were greatest for Philantomba maxwellii (0.46 indices km–1) and accounted for 68% of total encounters. Cephalophus niger, C. dorsalis and C. silvicultor were encountered at similar (0.07 indices km–1) but much lower rates. For all species, mean encounter rates were highest in degraded forest (0.38–0.73 indices km–1), followed by secondary (0.2–0.44 indices km–1) and primary (0.19–0.44 indices km–1) forest.
Conclusions: Of the four forest duiker species still present in the DSFR, the black, bay and yellow-backed duikers are the most affected by anthropogenic pressures. Duiker abundance in the DSFR varies with habitat type. This variation is apparently influenced by differences in forest structure, poaching pressure and proximity to villages.
Implications: The study provides baseline data for future managing of ungulate populations in the DSFR. We recommend that a biomonitoring study of duiker populations be initiated immediately to help determine population trends, investigate habitat preferences, and help curb illegal hunting activities in this important forest reserve.
Additional keywords: anthropogenic disturbance, conservation, dung pile, habitat preference, number of sightings, poaching signs.
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