Investigation on the road mortality of Anuran species on the Ikorodu-Epe/Ejirin-Ijebu Ode Roads in Lagos and Ogun States, Nigeria
The effect of road kills of anuran species by vehicular traffic on the Ikorodu-Epe/Ejirin-Ijebu Ode road in Lagos and Ogun States was investigated. The mean traffic density on the road during the survey (between 18:30-20:30hr and 06:00 and 07:00hr) was 127±45 vehicles/hr, which ranged between 72 and 216 vehicles/hr. A total of 738 anuran road mortalities among eight species were recorded [661 (89.6%) were identifiable, while 77 (10.4%) were not]. Ptychadena pumilio had the highest mortality of 67±27.1 individuals, while Xenopus muelleri and Aubria subsigillata were the least susceptible to road kills. This respectively represented 2.66±1.5 and 2.66±3 individuals each. Most mortality (256 individuals) occurred on the section of the road bordered by grassland/tertiary vegetation. However there was no significant difference (at P> 0.05) between the anurans killed along the different vegetation structures bordering the road (F2,21 = 0.415). About 473 live anurans belonging to five species were observed of which P. pumilio, the highest constituted the greatest number (81±42.9), while the least Hoplobatrachus occipitalis 7.3±4.2 was recorded. Both species had greater live counts than road kills compared to other anuran species that had greater road kills than live counts recorded. The greatest number of live anurans was recorded at where grassland/tertiaryvegetation occurred. This constituted a total of 198 individuals (41.8%), while the least occurred at the secondary/primaryvegetation which had 95 individuals (20%). However, the difference was not significant (F2,12 = 0.600) at P> 0.05. It is evident that anuran migration is an integral part of their biological activity. However vehicular traffic sadly possesses a negative effect on this activity. Precautionary measures are necessary to reduce population decline and possible extinction of not only the anuran species but also other wildlife species, which is a positive direction in the conservation of biological diversity.
Keywords: Vehicular traffic, anuran, mortality, vegetation, road kill, conservation