A researcher is investigating the impact of an invasive bug and the chemicals used to combat it on the wildlife inhabiting ancient hemlock forests. The hemlock woolly adelgid (HWA) has been causing significant damage to forests in southwestern Nova Scotia for nearly ten years. To control its spread, various entities including Parks Canada, the province, local groups, and private landowners have been employing insecticides like imidacloprid and dinotefuran.
Mathilde Christjansen, a master’s student at Mount Allison University in Sackville, N.B., highlighted the lack of knowledge concerning the effects of woolly adelgid and the insecticides on other species. She emphasized that imidacloprid, designed to impact insect nervous systems, has been detected in the brains of non-target animals like fish and tadpoles.
Instead of studying every species in all hemlock forests individually, Christjansen’s team is focusing on a single small amphibian as a representative of the ecosystem. The eastern red-backed salamander was chosen due to its sensitivity to environmental changes and pollutants, making it an ideal bioindicator species.
Researchers placed coverboards in forests last year to serve as salamander habitats and monitored them regularly to track salamander populations, conducting measurements and tagging exercises. Some forests under study are treated with either or both insecticides, while others remain untreated.
Behavioral tests were conducted on the salamanders found, including gentle prodding to observe their reaction to predation and flipping them over to assess their response time. Christjansen emphasized that the salamander’s well-being and characteristics can provide insights into the broader ecosystem’s health.
The study also examines how dying hemlocks impact salamanders. Chris Edge, a scientist with the Canadian Forest Service, explained that when hemlock trees perish due to HWA infestations, they disrupt the unique habitat conditions these forests offer.
The project involves collaboration between Mount Allison University, Canadian Forest Service, Acadia University, Environment and Climate Change Canada, and the University of Saskatchewan. It is part of a larger initiative focusing on forest health in Eastern Canada.
Christjansen noted that her research will continue until the following year, with data collected over the summer being analyzed. The findings will shed light on the implications of HWA and insecticide exposure on the forest ecosystem and its inhabitants.