PARENT SESSION
Contributed Oral Session 44: Mammal Ecology: Seals, Deer, and Bats
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 518 C, Level 5, Palais des congrès de Montréal
Little brown (Myotis lucifugus) and northern long-eared (M. septentrionalis) bat roost selection at different spatial scales.
Patriquin, Krista*,1, Chruszcz, Bryan2, 1 Dalhousie University, Halifax, Nova Scotia, Canada2 Parks Canada, Banff, Alberta, Canada
ABSTRACT- Many researchers argue that the availability of suitable roosts plays a larger role than does foraging habitat availability in determining bat distribution and abundance because of the importance of roosts in shelter and thermoregulation. Roost characteristics are well documented for many bat species. Yet, most studies have focused their attention on characteristics of the roost tree itself in comparison to available trees in the immediate area. However, mechanisms affecting the characteristics and thus availability of roost trees may vary with spatial scale. In addition, landscape features might be affecting roost site selection but have not been considered in most studies. Thus, the purpose of our study was to determine roost characteristics as well as landscape features that affect roost site selection by little brown (Myotis lucifugus) and northern long-eared (M. septentrionalis) bats. To address these questions we outfitted adult, female bats of each species with radio-transmitters and tracked them to their roosts. We measured each roost tree for typical features, such as, but not limited to, roost type, tree species, decay stage, canopy height, canopy closure, and number of available trees within an18m radius plot. To determine whether roost trees differed from trees available at random at different spatial scales, we made the same measurements outlined above for two trees chosen at random within the 18m plot of the roost, as well as within the same stand and four trees chosen at random in the entire study area per roost tree. As well, using a GIS map of the study area we measured the distance to the nearest road, edge and body of water from the roost tree and the random trees at each spatial scale. Consistent with other studies, preliminary analysis suggests that only decay stage and tree height of roost trees differed from trees available at random at the local and stand scale. However, in addition to these features, tree species also differed at the landscape scale. Unlike other studies, these bats preferred to roost under exfoliating bark rather than cracks or cavities. Data also suggest that these bats preferred roost trees closer to water than those available at random. These results indicate that the importance of roost tree features depends on the spatial scale at which they are compared.
Key words: roost selection, bats, northwestern alberta, spatial scale