Priorities for conserving bats in Nigeria
a. Egyptian rousette fruit bat. b. Bats sold at a village square. Credit: Benneth Obitte.
By Iroro Tanshi 1,2,3 and Benneth Obitte 1,2
A hotspot for bats in Africa spans southeastern Nigeria and southern Cameroon [1]. In addition, Nigeria has 12 terrestrial ecoregions making it the most ecologically diverse country in West Africa [2]. This amazing ecological diversity supports 90 bat species in Nigeria [3] with conservation status: Data Deficient – 6, Least Concern – 77, Near Threatened – 6, and Vulnerable – 1. However, new records say there are 100 bat species in Nigeria (Iroro Tanshi, unpubl. data), which is one-third of Africa’s bat diversity. Dedicated conservation of bats in Nigeria took off in 2012, with monitoring and roost protection of the Straw-colored Fruit bat (Eidolon helvum). Since then, bat conservation in Nigeria has grown to include two additional species; Egyptian rousette fruit bat (Rousettus aegyptiacus) and the Short-tailed round leaf nosed bat (Hipposideros curtus). Although conservation approaches would be species specific, a common strategy is roost protection and outreach. Here, we report bat conservation in a species-rich and ecologically diverse country, outlining impediments and solutions.
Intense hunting of large-bodied fruit bats for food is reported across West Africa, and Nigeria allows hunting of bats [4]. For instance, the straw-colored fruit bat is arguably Africa’s most hunted bat species. Although assessed as Near Threatened on the IUCN Red List, the species is listed on CMS (Convention on Migratory Species), being a long distant migrant. While forest roosts are known, these bats form big and conspicuous colonies in cities and towns, making them easy targets. Volunteer teams in Nigeria conduct bat monitoring in Abuja, Benin, Ibadan, Lagos and Ile Ife. With an alarming increase in hunting, roost protection proposals are under consideration by state environmental agencies and local NGOs.
The Egyptian rousette fruit bat is also in decline due to hunting pressure. It’s an obligate cave roosting species that is patchily distributed due to limited cave availability across its range. Forming large colonies, it is often the most abundant non-migratory resident fruit bat species. Large colony size and cave roosting habits makes the Egyptian rousette an easy target for hunters, who seal off cave entrances with fishing nets, killing bats with a combination of sticks, slingshots and guns. In southern Nigeria offtake levels can reach over 2000 individuals per hunter per cave visit (Benneth Obitte, unpubl. data). Although population density estimates are needed, anecdotal reports suggest serious population declines over the last three decades (Benneth Obitte, unpubl. data).
Efforts to protect roosts and conservation outreach programs to involve communities for conserving bats are ongoing. As both fruit bat species are major seed dispersers and pollinators, steep population declines jeopardize valuable ecosystem services, forest regeneration and ecosystem health. The goal for both fruit bat species is zero hunting in Nigeria.
The Short-tailed round leaf nosed bat is a rare range-restricted small cave roosting insectivorous species, endemic to Nigeria, Cameroon and Equatorial Guinea. Previously listed as Vulnerable B2ab(iii) on the IUCN redlist, [5] recent findings show increasing threats, and ongoing population declines, has revised the species to the Endangered list (Iroro Tanshi, in press). Heavy dependence on intact forest and undisturbed caves predisposes the species to threats from habitat loss (deforestation, logging and forest wildfires) and roost disturbance. In Nigeria, the major threats to the Short-tailed round leaf nosed bat are roost disturbance by hunters, and forest wildfires that spread from unattended farm brush fires in Afi Mountain Wildlife Sanctuary and Cross River National Park, both in southeastern Nigeria. Out of 35 known caves in the area, only one roost was to be found (Iroro Tanshi, unpubl. data). This is alarming because some previously known roosts have been destroyed elsewhere in the species range, threatening its survival [5]. Ongoing roost monitoring by rangers helps to prevent disturbances to the single roost known in Nigeria. Similarly, the ongoing Zero Wildfire Campaign engages local communities and their chiefs made local laws to end wildfire outbreaks.
In conclusion, bat conservation is growing in Nigeria but is constrained by lack of local capacity, limited knowledge of ecology and threats to bats, and inadequate enforcement of wildlife laws. Indeed, hunting and cave disturbance – two major threats to Nigerian bats – continue unabated in protected areas because the laws are poorly enforced for small mammals. This is often obvious among local people who associate conservation with mega-fauna such as apes and exclude bats and other small-sized mammals. An impetus for engaging the public, policy makers and law enforcement is badly needed. Therefore, to provide evidence-based conservation of bats in Nigeria, we launched the Bats of Nigeria Project in 2013, a collaboration between colleagues at local and international institutions investigating the taxonomy, distribution, and ecology of bats in Nigeria. Moreover, to facilitate country-wide conservation, the Bats of Nigeria Project builds local capacity through workshops and research fellowships to postgraduate students enrolled at universities across the country.
The outlined bat conservation, research and capacity building projects are funded by Bat Conservation International, Bat Conservation Trust, Den360 International, Idea Wild, Michelle Knapp Research Scholarship, National Geographic and Rufford Foundation. Ongoing efforts to protect bats in Nigeria are coordinated by Small Mammal Conservation Organization (SMACON) www.smacon-africa.org an NGO founded by the authors and registered in Nigeria.
References
1. Herkt, K. M. B., Barnikel, G., Skidmore, A. K., & Fahr, J. (2016). A high-resolution model of bat diversity and endemism for continental Africa. Ecological Modelling, 320, 9-28.
2. Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V., Underwood, E. C., D'amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., & Loucks, C. J. (2001). Terrestrial Ecoregions of the World: A New Map of Life on Earth - A new global map of terrestrial ecoregions provides an innovative tool for conserving biodiversity. BioScience, 51(11), 933-938.
3. Tanshi, I. (2014). Diversity of Bat Assemblages in three vegetation zones in southern Nigeria. Master’s Thesis, University of Benin, Benin City.
4. Mildenstein, T., Tanshi, I., & Racey, P. A. (2016). Exploitation of bats for bushmeat and medicine. In Bats in the Anthropocene: conservation of bats in a changing world (pp. 325-375). Springer, Cham.
5. Mickleburgh, S., Hutson, A.M., Bergmans, W. & Juste, J. (2008). Hipposideros curtus. The IUCN Red List of Threatened Species 2008: e.T10125A3169035. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T10125A3169035.en.
1. Texas Tech University, Lubbock, USA
2. Small Mammal Conservation Organization, Benin City, Nigeria
3. University of Benin, Benin City, Nigeria