From Caves to Culverts – Roost Selection and Roosting Ecology of the Large-footed Myotis (Myotis macropus)

The large-footed Myotis, Myotis macropus, is Australia’s only fishing bat. This species has adapted to living and breeding in urban areas and is found roosting in concrete culverts under roads. However, little is known about the selection and use of these unique roost sites.

We investigated roost selection and roosting ecology of M. macropus roosting in concrete culverts in Brisbane. We used a stratified sampling design and generalized additive models to analyse drivers in roost selection at a landscape scale and surveyed roost sites and surrounding culverts to examine roost availability and roost selection at a roost site scale.

We found a preference for culverts >1.2m in height, located on stream orders 3-5 and that culverts with microhabitat available for M. macropus to roost in were a limited resource. We deployed 18 VHF radio transmitters on non-reproductive adult females over two summers and two winters to study habitat use and roosting ecology. Key foraging areas, characteristics of roosts as well as frequency of roost switching were identified to get an understanding of movement patterns. Next Generation Sequencing (SNPs) of wing tissue was used to study gene flow and genetic diversity. Identifying the types of culverts that provide suitable M. macropus roost habitat and understanding how these roost sites and the landscapes around them are used will be used to inform conservation outcomes for this urban adapted bat.