Investigation on the usage of drainage structures between Kahramankazan and Gerede sections of Anadolu highway by bats (Chiroptera)

This study was carried out to determine if the drainage structures on the Anadolu Highway (Kahramankazan - Gerede) have a role in reducing the barrier effects for bats and to gather preliminary information for such studies to be carried out in Turkey. The study was carried out in 2018 and 2019, on the highway and 25 drainage structures under it. In order to determine bat activity in drainage structures, Photo traps and fixed ultrasonic recorders were used, and traces and signs were investigated. A mobile ultrasonic recorder was used to determine the activities of bats on the highway. Habitat characteristics of the structures and their surroundings were recorded in order to evaluate the drainage structures in terms of bat usege. According to these studies, bat passing was recorded in 24 out of 25 structures. A total of 18 species identified in the area, for Ankara 6 of them (Myotis nattereri, Myotis emarginatus, Nyctalus noctula, Nyctalus leisleri, Pipistrellus pygmaeus, Rhinolophus euryale), for Bolu 4 of them (Myotis nattereri, Nyctalus noctula, Pipistrellus pygmaeus, Rhinolophus euryale) were recorded for the first time. The highest activity in drainage structures belongs to Myotis emarginatus and Pipistellus pipistrellus, and the lowest activity belongs to Pipistrellus pygmaeus. Spearman correlation analysis was used to determine the relationship between the size of the drainage structures and bat activity, and accordingly the width of the structure was found to be the determining factor for bat passing. The activity level of the drainage structures in the 'invisible' entrance visibility is quite low compared to the 'visible' ones. Bat activity was detected in all 6 EUNIS habitat types (E1, G1, G3, G5, I1, X18). It has been determined that potential roost, feeding and round-trip habitats play an important role in bat activity. The bat activity level was found to be quite low in the structures with alternative passing structures nearby. These findings suggest that bats are more likely to prefer drainage structures that are wide and visible, with potential roosting habitats in the environment, and linked to guide lines through which they can make a round-trip. It has been evaluated that it is very important in terms of conservation biology to determine the habitats where especially bats show intense activity on the existing and to be built highways, and to construct drainage structures with these characteristics.