A researcher is examining the impact of an invasive bug and the chemicals used to combat it on the species residing in aging hemlock forests in southwestern Nova Scotia. The hemlock woolly adelgid (HWA) has been causing significant damage to these forests for nearly ten years. In response, various entities such as Parks Canada, local organizations, and landowners have employed insecticides like imidacloprid and dinotefuran to tackle the spread of the pest.
Mathilde Christjansen, a master’s student from Mount Allison University, is leading a study to investigate the effects of woolly adelgid and the insecticides on different species. She expressed concern about the potential impact of imidacloprid on various animals’ nervous systems, as traces of it have been detected in the brains of creatures like fish and tadpoles.
Instead of studying all species in every hemlock forest individually, Christjansen and her team are focusing on the eastern red-backed salamander as a bioindicator species to assess the overall ecosystem health. These salamanders are sensitive to environmental changes and pollutants, making them ideal for monitoring the forests’ well-being.
To conduct their research, scientists deployed coverboards in the forests to provide habitat for salamanders. They monitored the salamander populations under these coverboards, measuring and tagging them. Some forests are treated with insecticides, while others are left untreated to observe any differences in salamander behavior and health.
The team also conducted behavioral tests on the salamanders, assessing their reactions to simulated predation and their agility. The findings from these tests will help determine if the overall ecosystem is being affected by the presence of HWA and insecticides.
The study also examines how the decline of hemlock trees impacts salamanders. When hemlocks die due to HWA infestation, the unique habitat they provide is lost, affecting the forest’s microclimate and moisture levels critical for salamanders.
Collaborating institutions include Mount Allison University, Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan. The research is part of a larger project focusing on forest health in Eastern Canada.
The study, led by Christjansen, is ongoing and expected to continue into the following year. Data collected during the summer will be analyzed to further understand the implications of HWA and insecticides on salamanders and forest ecosystems.