A researcher is examining the impact of an invasive insect and the chemicals used to combat it on species residing in aged hemlock forests. Hemlock woolly adelgid (HWA) has been causing significant destruction in forests of southwestern Nova Scotia for nearly ten years. To counter its spread, various entities including Parks Canada, the province, local organizations, and private landowners have been utilizing insecticides such as 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 the insecticides on other species. She expressed concerns about the potential impact of imidacloprid on various animals beyond insects, citing its presence in the brains of fish and tadpoles.
Rather than individually studying all species across hemlock forests, the team is focusing on the eastern red-backed salamander as a bioindicator species due to its sensitivity to environmental conditions and pollutants. Coverboards were placed in forests to serve as salamander habitats, enabling scientists to observe, count, measure, and tag the salamanders underneath periodically.
Behavioral tests were conducted on the salamanders found, including light poking to assess their response to predation and flipping them over to observe their recovery speed. Christjansen emphasized that the salamanders’ well-being and characteristics could provide insights into broader ecosystem impacts. Julia Riley, an associate professor at Mount Allison University, highlighted the salamanders’ significance as forest health indicators due to their abundance compared to other wildlife.
The study also investigates the influence of dying hemlocks on salamanders. Chris Edge, a supervisor and scientist with the Canadian Forest Service, explained how the demise of hemlock trees disrupts the forest’s unique habitat qualities, like cool and moist microclimates, vital for salamanders. Salamanders, with their moisture-dependent skin, could face challenges if the forest becomes drier due to reduced foliage.
The project involves collaboration among Mount Allison University, Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan, as part of a comprehensive study on forest health in Eastern Canada. Christjansen plans to continue her study until the following year after analyzing the data and footage collected during the summer.