New records of bats and terrestrial small mammals from the Seli River in Sierra Leone before the construction of a hydroelectric dam.

Natalie Weber,Ricarda Wistuba,Jan Decher,Jonas Astrin

doi:10.3897/bdj.7.e34754

Abstract

Sierra Leone is situated at the western edge of the Upper Guinean Forests in West Africa, a recognised biodiversity hotspot which is increasingly threatened by habitat degradation and loss through anthropogenic impacts. The small mammal fauna of Sierra Leone is poorly documented, although bats and rodents account for the majority of mammalian diversity. Based on morphological, genetic and echolocation data, we recorded 30 bat (Chiroptera), three shrew (Soricomorpha) and eleven rodent (Rodentia) species at the Seli River in the north of the country in 2014 and 2016, during a baseline study for the Bumbuna Phase II hydroelectric project. In 2016, 15 bat species were additionally documented at the western fringe of the Loma Mountains, a recently established national park and biodiversity offset for the Bumbuna Phase I dam. Three bat species were recorded for the first time in Sierra Leone, raising the total number for the country to 61. Further, two bat species are threatened and endemic to the Upper Guinean Forest and several taxa of small mammals are poorly known or represent undescribed species. Overall, the habitats of the project area supported a species-rich small mammal fauna including species of global conservation concern. Suitable mitigation measures and/or offsets are necessary to maintain biodiversity and ecosystems in a region that is under high human pressure.

Highlights

Sierra Leone is situated at the western edge of the Upper Guinean Forest biodiversity hotspot in West Africa (Myers et al 2000, Bakarr et al 2001, Bakarr et al 2004)
Based on data from both study years combined, the total number of bat species occurring in Bumbuna II was estimated to be 38.3 (ICE), 39.4 (Jackknife1) and 45.0 (Jackknife2), respectively
Our study shows that Bumbuna II and its surroundings harbour a species-rich small mammal fauna and highlights the relevance of biodiversity surveys in understudied areas for impact assessments prior to major development projects

Summary

Introduction

Sierra Leone is situated at the western edge of the Upper Guinean Forest biodiversity hotspot in West Africa (Myers et al 2000, Bakarr et al 2001, Bakarr et al 2004). The three groups have important ecological roles and provide various ecosystem services (e.g. insect control, seed dispersal, pollination) Many species in these groups have highly specific habitat requirements and bats are recognised as a suitable indicator group to assess changes in the condition of ecosystems and conservation priorities (Jones et al 2009). Updates on distribution and ecological data for small mammals in Sierra Leone are urgently needed to identify conservation priorities and manage human impacts on biodiversity. Besides agricultural expansion, these impacts include large-scale development projects such as hydroelectric dams and mines, with effects on West African biodiversity that need to be thoroughly assessed, monitored and mitigated. Species distribution and ecological data are essential as a base for a range of other studies, e.g. zoonotic disease research (Guyton and Brook 2015, Han et al 2016, Pigott et al 2016)

Methods

Results

Conclusion