A researcher is investigating the impact of an invasive insect and the chemicals used to combat it on the wildlife in aged hemlock forests. The hemlock woolly adelgid (HWA) has been causing significant damage to forests in southwestern Nova Scotia for nearly ten years. In an effort to control its spread, various entities including Parks Canada, the province, local groups, and private landowners have been employing insecticides such as imidacloprid and dinotefuran.
However, 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 the insecticides on other species. Christjansen pointed out that while imidacloprid is designed to impact insect nervous systems, it has been detected in the brains of non-target animals like fish and tadpoles.
Instead of studying all species across multiple hemlock forests individually, Christjansen and the team are utilizing the eastern red-backed salamander as a bioindicator species to provide insights into the overall ecosystem’s health. These salamanders are sensitive to environmental conditions and pollutants, making them ideal for assessing ecosystem changes.
The study involves placing coverboards in forests to create salamander habitats, allowing scientists to monitor and tag the salamanders residing beneath them. Some forests are treated with insecticides, while others are left untreated. Behavioral tests are conducted on the salamanders found, including gentle poking to observe their response to predation and flipping them over to assess their recovery speed.
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 abundance in Eastern Canada woodlands. The study also examines how the decline of hemlock trees affects salamanders, considering their need for a moist environment.
Chris Edge, a scientist with the Canadian Forest Service and part of the research team, highlighted the importance of hemlock trees in providing ideal habitat conditions, such as cool and moist microclimates. The project involves collaboration among Mount Allison University, the Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan as part of a broader initiative on Eastern Canada’s forest health.
Christjansen plans to continue the study until the following year, gathering and analyzing data collected over the summer. The research aims to shed light on the complex interactions between invasive species, insecticides, and forest ecosystems, with a focus on the eastern red-backed salamander as a key indicator species.