Influence of forest disturbances on summer foraging activity of boreal bats at three spatial scales

Washinger, Darrian P. (2021) Influence of forest disturbances on summer foraging activity of boreal bats at three spatial scales. Masters thesis, Memorial University of Newfoundland.

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Abstract

Bat species worldwide have declined for several reasons, including natural and anthropogenic forest disturbances. In Gros Morne National Park (GMNP), Newfoundland, browsing by hyperabundant moose after insect disturbances has caused conversion of mature forests to open meadows (“moose meadow”, MM). I studied the influences of MM formation in GMNP on bat activity at fine (habitat), intermediate, and broad scales; the first investigation of such impacts by hyperabundant ungulate populations on bat activity. I hypothesized that bat activity would decrease in disturbed areas due to lower insect prey and incompatibility with foraging behaviour. I acoustically monitored bat activity and collected insects in disturbed, regenerating, and mature stand types throughout GMNP at 36 and 63 sites in 2017 and 2018, respectively. I used generalized linear mixed models (GLMMs) to determine significant predictors of bat activity. At the habitat scale, insect prey biomass varied among stand types, but bat activity did not; instead, fine-scale vegetation measurements were the most significant predictors of bat activity. At both the intermediate and broad scales, MM formation was positively associated with bat activity among species-specific responses to other variables. I concluded that MMs positively impacted activity of both species by increasing habitat heterogeneity at the broader landscape scale.

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