Factors influencing wildlife roadkill in the Ngorongoro Conservation Area, Northern, Tanzania

Globally, extension of road network is among the major threats affecting different fauna survival. Roads traversing protected areas, usually harm wildlife species (e.g., wildlife roadkill). Wildlife roadkill is of global conservation concern and has been reported to occur in different protected areas worldwide. Very little information on the problem is currently available in the Ngorongoro Conservation Area (NCA). The purpose of this study was to identify factors that affect wildlife roadkill in the NCA. The 82-kilometer main road from Lodoare to Golini served as the study's transects. Data was collected for a duration of one year from July 2021 to June 2022. Vehicle moving with a speed limit of 20km/hr were used during the data collection. The survey started early in the morning from 07:00 am to 06:00 pm and employed both direct and opportunistic encounter observations for recording wildlife roadkill incidences. The results revealed that 85 individual animals belonging to 21 families, i.e., 5 mammalian, 3 reptilian, and 10 bird orders were recorded killed within one year period in the area. These animals comprised 26 different species, which included 10 mammalian, 5 reptilian, and 11 bird species. Moreover, more birds (69.4%) than mammals (18.8%) and reptiles (11.8%) were found killed in the area. Additionally, the night jars (Caprimulgus europaeus; 30.6%) followed by black rat (Rattus rattus; 7.1%) and chameleon (Chamaeleo chamaeleon; 3.5%) were the most frequently recorded killed species in the area. Furthermore, wildlife roadkills did not differ significantly between seasons (p = 0.371) and time of day (e.g., morning vs. afternoon; p = 0.652) but differed significantly between their body size (e.g., small, medium, and large; p < 0.001) and habitat types (e.g., grassland, woodland, shrubland, wooded grassland, forest; p = 0.005). The study recommends punishments and penalties for overspeeding drivers and installing cameras, speed limits, and signboards along the highway to alert drivers to reduce speed. Further, providing regular education to road users on the impacts of roadkill within the ecosystem is critical.