A researcher is studying 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. Various entities including Parks Canada, the province, local groups, and private landowners have been applying insecticides such as imidacloprid and dinotefuran to control the spread of HWA.
However, Mathilde Christjansen, a master’s student at Mount Allison University, expressed concerns about the potential effects of these insecticides on other species besides the woolly adelgid. Christjansen highlighted the need to understand how imidacloprid, which targets insect nervous systems, may impact other animals. Studies have shown the presence of imidacloprid in the brains of creatures like fish and tadpoles, raising broader ecological questions.
Rather than examining all species in numerous hemlock forests individually, Christjansen’s team is focusing on a single amphibian species as a bioindicator. The eastern red-backed salamander is sensitive to environmental changes and pollutants, making it an ideal species to monitor ecosystem health overall.
The research involves placing coverboards in the forests to create habitat for salamanders. By periodically surveying these coverboards, scientists track salamander populations, conduct behavioral tests, and assess their overall health. The impact of insecticides on salamander populations and the broader forest ecosystem is a key focus of the study.
The project, led by Christjansen and supervised by Julia Riley and Chris Edge among others, is a collaborative effort involving Mount Allison University, Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan. The study forms part of a larger initiative examining forest health in Eastern Canada.
The research team is particularly concerned about the implications of dying hemlock trees on salamanders. Hemlocks provide unique habitat characteristics due to their dense canopies, which create cool and moist microclimates crucial for various species. The potential loss of these ecosystems could have far-reaching consequences for forest biodiversity.
Given the sensitivity of salamanders to changes in moisture levels and habitat conditions, the study aims to shed light on how declining hemlocks and insecticide use may impact these vital forest inhabitants. Christjansen plans to continue her research until the following year, analyzing the collected data to better understand the implications of HWA and insecticides on forest ecosystems.