A researcher is investigating the impact of an invasive insect and the chemicals used to combat it on the wildlife in aged hemlock forests. Hemlock woolly adelgid (HWA) has been causing significant damage to forests in southwestern Nova Scotia for nearly ten years. Efforts to control its spread have involved the application of insecticides such as imidacloprid and dinotefuran by Parks Canada, the province, local groups, and private landowners.
Mathilde Christjansen, a master’s student at Mount Allison University in Sackville, N.B., highlighted the lack of understanding regarding the effects of woolly adelgid and the insecticides on other species. Christjansen emphasized the potential impact of imidacloprid on various animals’ nervous systems, as it has been detected in the brains of creatures like fish and tadpoles.
Rather than examining all species across all hemlock forests individually, Christjansen’s team is using the eastern red-backed salamander as a bioindicator to assess the ecosystem’s status. This amphibian is sensitive to both environmental changes and pollutants, making it an ideal indicator of forest health.
The study involved placing coverboards in forests to create salamander habitats, with periodic surveys conducted to count, measure, and tag the salamanders found underneath. Some forests received treatment for HWA using insecticides, while others remained untreated. Behavioral tests were also conducted on the salamanders to evaluate their responses to predation stimuli and their agility.
Julia Riley, an associate professor at Mount Allison University and a supervisor of the study, highlighted the salamanders’ significance in indicating forest health due to their abundance. The study is also examining how dying hemlocks impact salamanders, as these trees provide unique habitat conditions essential for the species’ well-being.
The project, carried out in collaboration with various institutions, including Mount Allison University and the Canadian Forest Service, forms part of a broader investigation into forest health in Eastern Canada. Christjansen plans to continue her study into the following year, analyzing the collected data and field videos from the summer months.
The team’s research aims to shed light on the broader implications of HWA and insecticide use on forest ecosystems, particularly on sensitive species like the eastern red-backed salamander.
