Acadia leads research into tiny invader attacking NS Hemlock forests

From Springboard Content Lab and Acadia University

The Hemlock Woolly Adelgid (HWA) may look harmless. These creatures are tiny, cotton-like insects barely a millimetre in size – but don’t be fooled. These invasive bugs seriously threaten Nova Scotia’s old-growth hemlock forests, with potentially devastating consequences.

A Growing Crisis

Eastern hemlock trees are common throughout Nova Scotia, especially in the western regions and Kejimkujik National Park. These trees also grow across New Brunswick, Quebec, Ontario, and the eastern United States.

Since HWA was first discovered in Nova Scotia in 2017, it has spread rapidly. With no natural predators and warming temperatures due to climate change, these insects have already devastated forests elsewhere in North America, leaving behind what foresters call “grey ghosts” – the skeletal remains of once-thriving ecosystems.

“It’s not just a change in the landscape that’s at risk – but cascading ecological and economic destruction when entire tree species are lost. Old-growth hemlock are known for their dense canopies, which provide shade, regulate water systems, and support diverse wildlife. Without these trees, we would see significant impacts on forest biodiversity and community change, as well as increased soil erosion, all of which present significant environmental, economic, and human threats.”

Dr. Kirk Hillier, a biology professor at Acadia University

Hemlocks also improve air quality and store carbon. If HWA continues to kill these trees, forests could quickly shift from helping fight climate change to making it worse through decay and increased fire risk.

Fighting back with research

Dr. Hillier is leading efforts to combat this threat. With $1.2 million in funding from various sources, including NSERC, Research Nova Scotia, and Nova Scotia Environment & Climate Change, his team is pursuing several strategies:

First, they’ll study how insecticide treatments affect other forest species – birds, salamanders, pollinators, and invertebrates – to find the best conservation approach.

Second, they’re developing an HWA Biocontrol Facility at Acadia University’s K.C. Irving Environmental Science Centre. This facility will import natural predators of HWA (beetles and silver flies from British Columbia) to provide sustainable long-term control of the invasive insects.

A Team Effort

This project brings together researchers from Acadia University, Mount Allison University, and the University of Saskatchewan. It also creates learning opportunities for students through lab and field work, plus paid internships.

The initiative has secured partnerships with key organizations including Natural Resources Canada, Environment and Climate Change Canada, Parks Canada, and Nova Scotia government departments.

“With continued support of communities, industry, and government partners, these efforts could help ensure that our forests remain a vibrant part of the province for generations to come, all while nurturing the experiential education Canada’s future scientists need to become world leaders in environmental stewardship,” says Dr. Hillier.

The HWA project is just one of many climate change initiatives at Acadia University, which is also researching other climate-related challenges like the increasing presence of ticks and mosquitoes, and exploring sustainable materials like flax fibre to reduce carbon footprints in textile production.