A researcher is investigating the impact of an invasive insect and insecticides on species in old hemlock forests. The hemlock woolly adelgid (HWA) has been causing damage in forests in southwestern Nova Scotia for nearly ten years. To combat its spread, various entities like Parks Canada, the province, local organizations, and private landowners have been using insecticides such as imidacloprid and dinotefuran.
Despite this, Mathilde Christjansen, a master’s student at Mount Allison University in Sackville, N.B., points out that there is limited knowledge about how the woolly adelgid and the insecticides used against it are affecting other species. Christjansen highlights the potential impact of imidacloprid on various animals’ nervous systems, as it has been detected in the brains of creatures like fish and tadpoles.
Instead of studying all species in every hemlock forest individually, Christjansen’s team is focusing on using the eastern red-backed salamander as a bioindicator species to provide insights into the overall ecosystem health. The team placed coverboards in forests last year to serve as salamander habitats, allowing them to monitor and tag the salamanders living underneath periodically.
The study includes forests treated with insecticides, untreated forests, and behavioral tests on the salamanders found. By observing factors like salamander population size, health, and behavior in treated and untreated forests, researchers aim to understand broader impacts on the ecosystem.
Chris Edge, a scientist with the Canadian Forest Service, emphasizes the importance of hemlock trees for creating ideal salamander habitats due to their dense canopies. The project involves collaboration among Mount Allison University, Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan, forming part of a wider investigation into forest health in Eastern Canada.
Christjansen plans to continue the study until next year, analyzing the collected data and field videos from this summer to draw conclusions. The research also examines the influence of dying hemlocks on salamanders, as these creatures require a moist environment, which could be impacted if the forest becomes drier due to reduced foliage.