Fabio Petrozzi

Correlation between annual activity patterns of venomous snakes and rural people in the Niger Delta, southern Nigeria

BackgroundVenomous snakes are among the most serious health hazards for rural people in tropical regions of the world. Herein we compare the monthly activity patterns of eight venomous snake species (Elapidae and Viperidae) with those of rural people in the Niger Delta area of southern Nigeria, in order to identify the periods of highest potential risk for persons, and the human group actually at greater risk of snakebite.ResultsWe documented that above-ground activity of all venomous snakes peaked in the wet season, and that high snake activity and high human activity were most highly correlated between April and August. In addition, we documented that women and teenagers were at relatively higher risk of encountering a venomous snake than adult males, despite they are less often in the field than men.ConclusionsOur results suggest that future programs devoted to mitigate the social and health effects of snakebites in the Niger Delta region should involve especially women and teenagers, with ad-hoc education projects if appropriate. We urge that international organizations working on social and health problems in the developing world, such as IRD, DFID, UNDP, should provide advice through specific programs targeted at especially these categories which have been highlighted in comparatively potential higher threat from snakebites than adult men.

Are mammal communities occurring at a regional scale reliably represented in “hub” bushmeat markets? A case study with Bayelsa State (Niger Delta, Nigeria)

Abstract. Monitoring of bushmeat markets has traditionally been seen as a source of faunistic and ecological data on mammal communities in West Africa. Nonetheless, it is largely unexplored whether datasets coming from monitoring of large “hub” markets in towns can reliably picture the mammal faunas and community compositions at the local level. Here, Swali market in Bayelsa State, Nigeria, that is one of the largest bushmeat markets in the Niger Delta, was monitored for six months in 2013–2014. Data from Swali market were compared with those collected during regular field surveys at five protected forests situated within 15 km radius from the market. A total of 21 mammal species was recorded at Swali versus 29 in the five protected forests. The trade was more intense by wet season. There was a statistically significant linear relationship between mean weight of the sold mammal and its price. A considerable portion of species that occur at the protected forests did not occur in the market samples, including the very rare species and the smallsized species. However, the abundance in the market of the common species was positively related to their apparent field abundance in the forest reserves. Therefore, it is concluded that large-sized bushmeat markets did not depict reliably the whole faunal composition and the community structure of mammals in West Africa, although these types of surveys are sufficient to characterize the abundance distribution of the common species at the regional scale.

Preliminary surveys of the terrestrial vertebrate fauna (mammals, reptiles, and amphibians) of the Edumanon Forest Reserve, Nigeria

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.

Surveys of mammal communities in a system of five forest reserves suggest an ongoing biotic homogenization process for the Niger Delta (Nigeria)

Community composition and an index of relative abundance were analyzed for mammals (excluding most rodents, shrews and bats) of five forest reserves in the Niger Delta (Southern Nigeria). Twenty-nine species were recorded, 86.2% of them being found in all protected areas. Although most of the species were already known from the study area, there were unexpected patterns concerning the duikers. Indeed, the presence of only one species (Philantomba walteri) (CH Smith, 1827) was confirmed, whereas at least five additional duiker species were reported for the study area by earlier authorities. Another duiker species (Cephalophus niger Gray, 1846) was recorded once during the present surveys and is not known whether it represents a stabilized presence in the Niger Delta. The empirical Abundance Index suggested that only three species were very rare (Trichechus senegalensis (Link, 1795), C. niger, and Pan troglodytes (Blumenbach, 1775)). Diversity-dominance diagrams showed that the evenness profiles were similar across study areas. Linear distance (Km) between the barycenters of forest reserves was significantly positively correlated with relative community composition dissimilarity. Overall, a biotic homogenization process for the mammal communities of the five forest reserves was observed, likely as an outcome of the high deforestation of the last 50 years.

Turtles and Tortoises of Togo: Historical Data, Distribution, Ecology, and Conservation

Abstract The chelonian fauna of Togo (West Africa) has been scarcely studied to date. In this article, we review and summarize all available data on the distribution, ecology, and conservation status of the chelonian species of Togo and present a short historical perspective on the development of studies on these reptiles. Overall, 13 chelonian species are found in Togo, 4 being marine, 3 terrestrial, and 6 freshwater. Among the marine species, only 2 of them nest on Togolese beaches (Lepidochelys olivacea and Dermochelys coriacea). Two species (Chelonia mydas and L. olivacea) are still locally common. Concerning the terrestrial and freshwater species, they differed remarkably in terms of their distribution by ecological zone. Cluster analyses revealed the existence of 3 clusters of species, 1 that contains the “forest” species, 1 accommodating the Sudanese savannah species, and a third cluster for the generalist savannah species. The conservation status of the various species and their dissimilarities in terms of threat score categories were assessed through a multivariate model following published work on African chelonian species in general. The results of this model indicate that the potentially most threatened species in Togo are Kinixys erosa, Kinixys homeana, and the 2 Cyclanorbis species (C. senegalensis and C. elegans), with Trionyx triunguis also being possibly seriously threatened. Overall, using the International Union for Conservation of Nature Red List criteria, the concurrent presence of 2 Critically Endangered (K. homeana, C. elegans), 1 Endangered (K. erosa), and several Vulnerable species shows that the chelonian fauna of Togo should be of priority relevance for the competent international agencies.

Checklist of the lizards of Togo (West Africa), with comments on systematics, distribution, ecology, and conservation

ABSTRACT The lizard fauna of Togo, a country situated within a natural gap in the rainforest zone of West Africa, is reviewed and updated. In this article, we summarize all available data on the distribution, ecology, and conservation status of the 43 lizard species of Togo. Species richness is uneven between vegetation zones. The submontane forest (ecological zone IV), despite being the smallest, houses the greatest number of species (n = 27), followed by dry forest (ecological zone II, n = 21). Currently none of the Togolese lizard species appears to be immediately threatened. However, several species are subjected to exploitation for the international pet trade and in-country use (bush-meat, fetish market), and could become threatened in the next decades. The intensity of this trade should be carefully monitored in the years to come.

Aspects of the ecology of the tortoise Kinixys nogueyi (Lataste, 1886) in Togo and Nigeria (West Africa)

In this study, the sex ratio, habitat use, and diet of free-ranging Kinixys nogueyi are examined. Sex ratio and habitat use were examined in Togo and Nigeria (West Africa), and food habits only in Nigeria. Sex ratios were equal in both populations. Tortoises had clear habitat preferences in both countries, and the Nigerian population exhibited seasonal but not inter-sexual differences in habitat selection. The present study demonstrated that this species inhabits not only Guinea savannahs and relatively wet savannahs, as already reported in the literature, but also rainforest patches and hilly forests, especially in Togo. Food remains in the feces of Nigerian specimens belonged to plants and fungi as well as to animals, with inter-seasonal but not inter-sexual differences in dietary composition. In particular, there was a significant shift from a diet based mostly on animal food in the dry season towards a mainly vegetarian diet in the wet season.

Bushmeat consumption in the West African Sahel of Burkina Faso, and the decline of some consumed species

To explore the patterns of bushmeat trade in the Sahel we carried out a multidisciplinary study, focusing on Burkina Faso. We conducted baseline interview surveys to examine the variation in peoples perceptions of bushmeat in relation to their place of residence (urban vs rural), sex and age. We also analysed the long-term (1985–2010) population dynamics of two ungulate species, the oribi Ourebia ourebi and the common duiker Sylvicapra grimmia, known to be among the main targets of the bushmeat trade locally. For the antelopes we chose as our study area a protected area (Nazinga Game Ranch) where poaching activities occur and are likely to represent a threat to the local wildlife. The results of the interviews underlined significant differences in bushmeat consumption between rural and urban areas. In particular, the probability of finding people who did not consume bushmeat increased in the urban area, where bushmeat is less available than in the rural areas. Sex and age did not have any effect on peoples perceptions of bushmeat. In Burkina Faso bushmeat is still widely consumed, and this could be because the bushmeat trade is poorly controlled, with a lack of enforcement of the legislation. Long-term field surveys revealed that the oribi and the common duiker have declined significantly in Nazinga Game Ranch, suggesting that the bushmeat trade in Burkina Faso may have negative consequences in terms of the conservation outlook for these species.

Inter-seasonal and inter-habitat variations in the diet of the African fire skink, Lygosoma fernandi, from southern Nigeria

The inter-habitat and inter-seasonal variations in the taxonomic diet composition of the African fire skink, Lygosoma fernandi, one of the largest Scincidae of the Afrotropical regions, were studied by analysis of excrements collected from live individuals that were captured in some areas of the Niger Delta region, southern Nigeria. 22 prey types, mostly arthropods, were found in the diet of this species, with significant differences in prey composition between seasons. Isopoda and Coleoptera dominated in the dietary samples, with very few prey types exclusive of one habitat type and/or season (e.g. Formicidae in dry forest in both seasons and lizards in swamp forest in wet season). Overall, no difference between forest types and seasons was found as for diversity and evenness indices except for that prey diversity was higher in feces collected in the dry forest in dry season, whereas dominance and evenness did not show any significant variation across forest types.

Effects of rainfall and geography on the comparative diets of eight rainbow lizard populations across Togo, Benin and Nigeria (West Africa)

The diet composition of rainbow lizards (Agama agama complex) populations was studied by feces analysis at eight distant places across a mega-transect in the Gulf of Guinea (West Africa), covering three countries: Togo, Benin and Nigeria. The effects of geography (= linear distance between study sites) and local conditions (using the mean annual rainfall as a proxy of the site-specific conditions) on dietary similarity of rainbow lizards were tested. Rainbow lizards were mainly insectivorous at all sites. Multivariate analyses identified four main groups of localities in terms of diet diversity indexes, with populations inhabiting forest towns tending to have less prey taxa richness than conspecifics from more arid areas, which instead had higher dietary evenness. Food niche overlap between populations was high among populations (range 0.631-0.940, x = 0 . 839 ), and decreased with increases in the difference of mean annual rainfall between sites. There was no effect of the geographic distance on the similarity in diet composition between populations. A UPGMA dendrogram revealed a geographic trend in terms of presence/absence of the various prey types in the diets, with all the Nigerian study sites forming one cluster, whereas Lome and Cotonou, two cities situated within the Dahomey Gap, being grouped apart. Overall, rainfall of the various sites seems to be more important than geographic distance for determining the taxonomic diet composition similarity of these lizards.