10 research outputs found

    The conservation status of West African vultures: an updated review and a strategy for conservation

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    The vulture populations in West Africa are undergoing dramatic decline over the last 30 years. Their particular ecology and sociality makes them vulnerable to various risks, including environmental changes, poisoning and bioaccumulation of toxic substances from agricultural products, pesticides, and veterinary drugs used in cattle livestock. In addition, these birds are subject to direct persecution for the trade of products used in traditional medicine. This manuscript analyzes the conservation status of eight vulture species in West Africa and the threats affecting their survival. In order to assess the conservation status of vultures in West Africa, this paper analyzes all the available literature that has been published in scientific peerreviewed journals, including also technical reports and unpublished reports related to the whole West African region. Overall, and despite the high risk of extinction facing several vulture species all throughout the world, our literature surveys revealed that the scientific papers on the conservation of West African vultures are relatively few. Therefore, due to limited available literature, the main causes of vulture declines in West Africa remain relatively unclear. Apparently, all African vultures suffer from similar threats, especially poisoning, habitat alteration and conversion to agro-pastoral systems, loss of wild ungulates leading to a reduced availability of carrion, hunting for trade, for use in traditional medicine and bushmeat, persecution and human disturbance. Our review also addresses future steps that are needed for reversing the negative population trend of their free-ranging populations, including some specific conservation measures that are proposed to mitigate their decline

    The cichlids of Eniong and Cross Rivers, Niger Delta, Nigeria

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    Taxonomy and biodiversity is an important aspect of fish studies as it gives fish scientists information about the types of fish present, their name and classification based on discrete sets in a given locality. This study is on the taxonomy and bio-diversity of Cichlids collected from the Eniong River and the Lower Cross River in the Niger Delta, Nigeria between January and June 2020. A total of 358 cich-lids were collected from three sampling stations (the Eniong River, the confluence and the lower Cross River). Sampling was conducted with active and passive sampling techniques with the help of local fishermen using various fishing gears including beach net (10 – 15 m length, 2 –3.5 m height, mesh size of 0.5 – 5cm), fixed gill net (40 – 60 m long, mesh size 15 – 57 mm), cast net (2 – 5 m diameter, mesh size 15 – 20 mm) and local traps (made from raffia palm). The sampling du-ration with the fishing gear and methods were approximately the same. Gill nets and traps were set between 1600 h and 1800 h and fishes caught were removed from the gear between 0600 h and 0900 h the next day. Fish were identified using morphological and meristic traits. The species found and percentage abundance were; Coptodon zilli (5.9%), Coptodon dageti (31.2 %), Coptodon guineensis (16. 4%), Hemichromis elongatus (6.4 %), Hemichromis fasciatus (2.2%), Ore-ochromis niloticus (5.3%), Oreochromis aureus (0.8%), Sarotherodon melanotheron (3.6%), Sarotherodon galileus (0.8%), Sarotherodon macrocephala (1.95%), Chromidotilapia guntheri (10.3%), Pelmatolapia mariae (12.3%), Tylochromis sudanensis (1.7%) and the unidentified species(0.8%). There was higher abundance of cichlids in Eniong River (36%) than in the confluence (34%) and lower Cross River (30%). Simpson’s diversity index was 0.97 - 0.98 in the three stations. Shannon-Wiener’s index of diversity was 2.18 in Station 1, 1.76 and 1.68 in stations 2 and 3 respectively. Margalef index of diversity was 2.05 in station 1 and 1.66 and 1.71 in stations 2 and 3 respectively. Some species ap-peared to be specific in their habitat; O.niloticus, O.aureus, S. macrocephala were found in freshwater. S. galileus in the estuarine habitat while all other spe-cies were found in all the stations. A dichotomous key which will serve as a guide for fish scientist in the field was prepared using morphomeristic characters

    The case of rainforest stiletto snakes (genus Atractaspis) in southern Nigeria. Evidence of diverging foraging strategies in grossly sympatric snakes with homogeneous body architecture?

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    we report some data on the food habits of free-ranging Atractaspis in rainforest habitats of southern Nigeria, and suggest a discussion point that could serve as basis for investigating the evolution of Atractaspis species in homogenous habitats where they occur sympatrically

    The ecological distribution of Causus (Viperidae) in Nigeria, with special reference to Causus resimus and Causus lichtensteini, two species rarely recorded from this country.

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    New data for snakes of the genus Causus Wagler 1830 (Viperidae) are reported for Nigeria, with emphasis on their ecological distribution and biology. Causus rhombeatus (Lichtenstein 1823) was never observed during our long-term field study, and is probably a very rare species in Nigeria, confined to a small area in the north-east of the country. We confirmed that Causus maculatus (Hallowell 1842) is widespread in Nigeria, inhabiting a wide variety of ecological regions, from the rainforests of the south to the Sudanese savanna in the north. It feeds on amphibians, mainly ranid frogs. Causus resimus (Peters 1862) was reported to occur in Nigeria only on the basis of a few specimens without precise locality. We found three vouchers with known locality of capture in the Zoological Museum of Copenhagen, and we captured a few other specimens in the field. Although probably rare (given the very few captures), this species has a wide distribution in Nigeria, mainly in savannas and forest-derived savannas. It feeds on toads. Causus lichtensteini (Jan 1859) was occasionally captured in the swamp-forests of the Niger Delta (southern Nigeria), but seems to be absent from other forested regions of the country. It is also an anuran-eate

    Determining the composition and structure of antelope communities in three study sites within the Niger Delta (Nigeria) based on bushmeat market data

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    The composition and structure of antelope assemblages were analyzed by using data from wild meat markets in three distinct study stations in the southern Niger Delta, Nigeria. The relative abundance of the different species coming into the markets was analyzed, and various diversity metrics were used to describe the different antelope communities. Sex ratios of these populations as well as the effect of season on the abundance of the various species in the markets were examined. It was observed that a single recently described species (Philantomba walteri) was the dominant species in the three localities, contributing about 70% of all the antelope individuals. The relatively low number of antelope carcasses observed in this study (less than the number of carcasses of small carnivores in the same sites) suggests that the ungulate fauna is already very depleted in the eastern Niger Delta region, with these mammals being hunted more intensely in the wet season

    Are snake populations in widespread decline?

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    Long-term studies have revealed population declines in fishes, amphibians, reptiles, birds and mammals. In birds, and particularly amphibians, these declines are a global phenomenon whose causes are often unclear. Among reptiles, snakes are top predators and therefore a decline in their numbers may have serious consequences for the functioning of many ecosystems. Our results show that, of 17 snake populations (eight species) from the UK, France, Italy, Nigeria and Australia, 11 have declined sharply over the same relatively short period of time with five remaining stable and one showing signs of a marginal increase. Although the causes of these declines are currently unknown, we suspect that they are multi-faceted (such as habitat quality deterioration, prey availability), and with a common cause, e.g. global climate change, at their root
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