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Luiselli, Luca; Akani, Godfrey C.; Ebere, Nwabueze; Angelici, Francesco Maria; Amori, Giovanni; Politano, Edoarto
(detail)
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2012 |
Macro-habitat preferences by the African manatee and crocodiles – ecological and conservation implications.
Web Ecology 12: 39-48. DOI:10.5194/we-12-39-2012 July 2012.
–ABSTRACT: African manatees (Trichechus senegalensis) and crocodiles are threatened species in parts of their range. In West Africa, crocodiles may constitute the main predators for manatees apart from humans. Here, we explore the macro-habitat selection of manatees and two species of crocodiles (West African crocodiles Crocodylus suchus and dwarf crocodile Osteolaemus tetraspis) in the Niger Delta (Nigeria), testing the hypotheses that (i) manatees may avoid crocodiles in order to minimize risks of predation, and (ii) the two crocodile species do compete. The study was carried out between 1994 and 2010 with a suite of different field techniques. We observed that the main macro-habitat types were freshwater rivers and coastal lagoons for manatees, mangroves for West African crocodiles, and rivers and creeks for dwarf crocodiles, with (i) the three species differing significantly in terms of their macro-habitat type selection, and (ii) significant seasonal influence on habitat selection of each species. Null models for niche overlap showed a significantly lower overlap in macro-habitat type use between manatee and crocodiles, whereas the two crocodiles were relatively similar. Null model analyses did not indicate any competitive interactions between crocodiles. On the other hand, manatees avoided macro-habitats where crocodiles, and especially West African crocodiles, are abundant.
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Akani, Godfrey C.; Aifesehi, Pedro E. E.; Petrozzi, Fabio; Amadi, Nioking; Luiselli, Luca
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2014a |
Preliminary surveys of the terrestrial vertebrate fauna (mammals, reptiles, and amphibians) of the Edumanon Forest Reserve, Nigeria.
Tropical Zoology 27(3): 63-72. 2 tabs. 3 figs. DOI: 10.1080/03946975.2014.944376. July 3, 2014.
–ABSTRACT: The Edumanon Forest Reserve is one of the least explored protected areas in the Niger Delta region of southern Nigeria, West Africa. In this article, we report the results of preliminary surveys, conducted between 2011 and 2014, for determining a checklist and a relative estimate of abundance for three groups of vertebrates, namely mammals, reptiles, and amphibians. Overall, we detected 69 vertebrate species (birds excluded), several of them being of high conservation concern. Among the most remarkable species from the conservation point of view, we can cite the chimpanzee, the manatee, and three species of sympatric crocodiles. Analysis of the reptile diversity suggested that species dominance was high and evenness was low, thus revealing altered ecological conditions in this forest area. Nonetheless, several forest specialists were still observed in this forest reserve. The conservation implications of the observed patterns, together with some ethnozoological data, are also discussed.
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Akani, Godfrey C.; Aifesehi, Pedro E. E.; Petrozzi, Fabio; Amadi, Nioking; Luiselli, Luca
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2014b |
Diversity of terrestrial vertebrates in Taylor Creek forest reserve, an area of high environmental value in the River Niger Delta (Bayelsa State, Nigeria).
Vie et Milieu - Life and Environment 64: 59-68. Dec. 2014.
–ABSTRACT: The Taylor Creek Forest reserve (Bayelsa State) is one of the most important protected areas of the River Niger Delta region, southern Nigeria. Unfortunately, however, no field studies are available on the diversity of the terrestrial vertebrates (amphibians, reptiles, mammals) in this protected territory. Here, we report the results of field surveys devoted to assess on a preliminary base the vertebrate diversity of Taylor Creek Forest reserve. Mammals and amphibians were assessed only qualitatively, whereas reptiles were assessed also quantitatively within 15 plots of 2 ha area. We detected about 70 vertebrate species (some genera may include multiple species that remained non-detected in our surveys). Several of the recorded species were of high conservation concern (e.g. manatee, dwarf crocodile, hinge-back tortoises, etc.). The presence of the endangered Nigerian chimpanzee was suspected for the Forest Reserve, and indeed few groups of this species do occur in the surroundings of the protected area. Analysis of the reptile diversity suggested that, however, species dominance was high and evenness was low, with very few lizard species dominating the samples. Thus, the reptile community diversity profile revealed altered ecological conditions in this forest area. The conservation implications of the observed patterns are also discussed.
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Bibliography and Index of the Sirenia and Desmostylia 