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. To control its spread, various entities such as Parks Canada, the province, local groups, and private landowners have been employing insecticides like imidacloprid and dinotefuran.
Mathilde Christjansen, a master’s student at Mount Allison University in Sackville, N.B., highlighted the lack of knowledge regarding the effects of woolly adelgid and insecticides on other species. She pointed out that imidacloprid, designed to impact insect nervous systems, has been detected in the brains of other animals like fish and tadpoles.
Instead of individually studying all species in every hemlock forest, Christjansen’s team is focusing on using the eastern red-backed salamander as a bioindicator species to provide insights into the overall ecosystem health. These salamanders are sensitive to environmental conditions and pollutants, making them ideal candidates for assessing forest well-being.
The researchers placed coverboards in the forests last year to serve as salamander habitats, periodically monitoring them to observe salamander populations, conduct measurements, and apply tags. Some forests are treated with insecticides, while others remain untreated for HWA. Behavioral tests were conducted on the salamanders found, including gentle prodding to assess their response to predation and observation of their agility when flipped upside down.
Julia Riley, an associate professor at Mount Allison University and a Canada Research Chair in integrative wildlife ecology, emphasized the salamanders’ significance as indicators of forest health due to their reactivity to environmental changes and their abundant presence in forest ecosystems.
The study also examines how the decline of hemlock trees impacts salamanders. Chris Edge, a supervisor and scientist with the Canadian Forest Service, explained that dying hemlocks alter the forest’s microclimates essential for salamander habitats, potentially leading to adverse effects on salamander populations and behavior.
The research project involves collaboration between Mount Allison University, Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan, as part of a broader investigation into forest health in Eastern Canada.
Christjansen plans to continue her study until the following year, analyzing the data and videos collected during the summer months. The findings aim to shed light on the implications of HWA and insecticides on forest ecosystems and wildlife, particularly salamanders.
