A researcher is investigating the impact of an invasive insect and the chemicals employed to combat it on the wildlife inhabiting ancient hemlock forests. Hemlock woolly adelgid (HWA) has been causing significant damage to forests in southwestern Nova Scotia for nearly ten years. Various entities, including Parks Canada, the province, local groups, and private landowners, have been utilizing insecticides such as imidacloprid and dinotefuran to control its spread.
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 the nervous systems of various animals, as traces of this chemical have been detected in the brains of fish and tadpoles.
To gain insights into the broader ecosystem, Christjansen and her team are focusing on the eastern red-backed salamander, a bioindicator species sensitive to environmental changes and pollutants. By studying this amphibian, they aim to gauge the overall health of the forest.
In their study, researchers placed coverboards in forests last year to create salamander habitats. They monitored these boards regularly to assess salamander populations beneath them, conducting measurements and tagging procedures. Some forests under study are treated with imidacloprid, dinotefuran, or both, while others remain untreated.
Behavioral tests were also conducted on the salamanders, including gentle prodding to observe their response to predation threats and flipping them to assess their agility. Christjansen emphasized that the condition and behavior of the salamanders could serve as indicators of potential ecosystem impacts.
Julia Riley, an associate professor at Mount Allison University and a Canada Research Chair in integrative wildlife ecology, explained that salamanders are valuable indicators of forest health due to their abundance and biomass within Eastern Canadian woodlands.
The research project, overseen by Christjansen, Edge, and Riley, involves collaborations with various institutions such as Mount Allison University, the Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan. The study forms part of a larger investigation into forest health in Eastern Canada.
Christjansen plans to continue her research until next year, analyzing the collected data and field videos gathered over the summer. The study also examines the repercussions of dying hemlocks on salamanders, as these trees create an essential habitat that supports salamander populations.