Acoustic monitoring of bird community composition in emerald ash borer damaged and at risk Southern Ontario forests

Abstract

The invasive beetle Emerald ash-borer (EAB), is killing North American ash trees, and the subsequent loss of canopy could change avian community composition. Birds are vulnerable to canopy alteration and their vocal behaviour, integral to social systems, indicate consequences of habitat change. I recorded bird vocalizations to characterize community composition and investigated current and potential influences of EAB canopy damage. In chapter 1, I examined recordings in Oakville, Ontario, where ash morality has reached 98%. With unmanned aerial vehicle acquired images and pixel-based analysis, I measured canopy cover in plots with ash mortality or no ash mortality. Species richness was similar, however, when separating species by foraging substrate, I found a significantly larger proportion of bark foragers representing the community in ash mortality plots. In York Region, Ontario forests, I detected minimal canopy damage and similar avian community composition across forests varying in ash components. Avian communities are influenced by EAB, with a higher proportion of bark foragers in forests with ash morality. In chapter 2, I characterized optimal sampling schedules for avian communities in forests susceptible to EAB. I recorded 14 plots for 48 hrs in May (before ash flush) and again in June (during EAB forestry work). Among earlier recordings, community composition was similar in ash stands. Species detections were significantly higher in May. In June, significantly fewer migrant species were detected as were members of most feeding/foraging guilds compared to May. With more detections in spring, my research emphasizes early sampling in the breeding season and offers a potential protocol for continued monitoring of EAB and the response of birds.