Climate change, invasive species and the Great Lakes

From February 7 to 9, more than 900 attendees participated in the virtual 2023 Invasive Species Forum, which focused this year on invasive species action in a changing climate. Keynote presenter Dr. Gail Krantzberg, a professor at McMaster University’s Walter G. Booth School of Engineering Practice and Technology spoke about the link between climate change and invasive species in a Great Lakes context, calling for “a new era of science, of predictive science that will help us understand threats to the region and enhance the resilience of the Great Lakes.”

There is much uncertainty about invasive species and changing climate. What is known is that we’re going to see more frequent extreme weather: an increased severity of storms, more floods and prolonged periods of drought. There will be extremes in lake levels, both highs and lows. “That’s the point,” Dr. Krantzberg said. “It’s extremes. When we get extreme drops, we lose habitat and wetland habitat and create more stress on native biodiversity.”

These changes could result in the loss of nearshore zones throughout the Great Lakes, leading to displacement or disappearance of coastal wetland species and the potential increase of alien species coming in because of thermal shifts: where the water was once too cold and the winters too brutal, it’s now possible for them to survive. We will see a shift towards warm water species, including alien invasive species, and they are very damaging.

A 2000 report from the American Institute of Biological Sciences noted damages from non-indigenous plants, fish, molluscs, insects and terrestrial plants (in the United States alone) were over $2.5 billion a year. That cost has likely risen.

“That doesn’t even account for the true costs of species extinctions,” said Dr. Krantzberg. “How do you put a value on the loss of biodiversity or aesthetic damages?”

Take zebra mussels, for example. Municipalities spend millions every year ensuring that infrastructure pipes don’t become clogged with them and destroy the water infrastructure. What’s not as generally known is the damage zebra mussels cause to native species. “Zebra mussels like to go where the water is moving and so they smother our native species,” Dr. Krantzberg said.

Zebra mussels were first introduced into the Great Lakes through ballast tank releases from ocean-going ships originating in the Black Sea. “Now zebra and quagga mussels are everywhere, causing these massive damages to the system,” said Dr. Krantzberg. They don’t much like cold water, so Lake Superior and the depths of Huron and Michigan might see little impact; however, their quagga mussel cousins very much like when it’s cold.

Emerging invasive species threats include the spotted lanternfly, the jumping worm and the kudzu vine. The spotted lanternfly could potentially destroy the fruit and grape crop in the Niagara region, and has been detected across the border in Niagara Falls, New York. The jumping worm is already in Ontario. Native to East-Central Asia, jumping worms like to feast on mulch and topsoil, causing erosion and killing plants. They cause a lot of environmental damage where they are established. Kudzu, a fast growing vine native to southern United States, has been found in Leamington, Ontario.

The history of invasive species in North America dates back to the turn of the twentieth century, when plants were brought across the ocean as horticultural ornamentals. Purple loosestrife is a perfect example, noted Dr. Krantzberg. “It’s a pretty Eurasian plant but also can destroy wetlands. As time moves on, we’re seeing more crustaceans, some fishes and some microbial invaders as well. The non-indigenous aquatic species are very diverse, so you can imagine the impacts on the system are equally diverse.”

Over time, species range and advancement is limited by climate, the severity of the winters, the coldness of the waters, or the habitat of the forest. When the climate becomes favourable, the species is able to find it, reproduce and then rapidly grow. “They can grow exponentially, which means if we don’t catch them before they come and keep our eyes out for them, the cost of control is enormous,” she said. “There’s a lot of science that we need to understand: where these species are around the globe, how they might be able to get to the Great Lakes, and which ones might be able to get to the Great Lakes. We need to be united in our science because early warning systems can reduce the risk of invaders.”

Billions of dollars have been spent on restoration efforts in the United States through the Great Lakes Restoration Initiative. The Canadian and Ontario governments have also focused their efforts on restoration and remediation. No such money has been invested for over 20 years in revitalizing, modernizing Great Lakes science, she pointed out.

Dr. Krantzberg is also Canadian Co-chair of the International Joint Commission Great Lakes Science Advisory Board – Science Priority Committee. As part of her role in that position, she has helped lead the work group for the Great Lakes Science Strategy for the Next Decade project.

“We really need to understand better how climate change is affecting the Great Lakes and will for the next 20 to 50 years,” she said. “We need big science and big data in order to do that.”

There are new pressures affecting the ecosystem, the economy and social cohesion of the region, she added. Communities, cities, conservation authorities and others are looking for solutions to adapt and respond to new pressures, including pressures that are not yet seen. “A science plan could collect the information needed to forecast change, to forecast which species in which part of the world would find it favourable to come into the Great Lakes, as well as how we might stop them from coming here.”

There’s a winter component to the science need: What happens in the lakes during the winter months? What happens under the ice, and what happens where there’s no ice? There are also questions about the food web, about invasive species and changes in chemical and nutrient cycling in the Great Lakes.

That’s not all. “We need to deal with equity, diversity and inclusion in Canada. How do we think about our underserved groups like our important Indigenous tribes and First Nations that don’t even have safe drinking water?” she asked.

Dr. Krantzberg wants to see people, governments and groups coming together in genuine collaboration, rather than working in silos. Centres of Excellence should be established to advance interdisciplinary science, support management and policy development, and address economic decision making.

“We could have a Centre of Excellence for traditional ecological knowledge and build on thousands of years of Indigenous observations on the Great Lakes to tell us what’s changing, fine-tune what’s changing,” she suggested. “They could tell us how to integrate traditional ecological knowledge with western science, if it can be done. There’s lots of opportunities for these centres of excellence to happen and to engage new researchers, get youth to populate the Great Lakes research agenda and be the next generation of change agents.”

The decisions of today can slow the spread of invasives, improve the climate, reduce greenhouse gases and adapt to a changing climate more proactively.

“I’ll be very frank here,” said Dr. Krantzberg. “If we fail in all of this, the planet will survive. Biodiversity will be completely different. It will not support humanity the way we know it, but the planet will survive. There’s no Planet B for humanity.”

She warns that successfully adapting to a changing climate doesn’t mean there won’t be negative impacts, but those that do occur will be less severe. She’s a big fan of adaptation, such as improving the way water permeates through the ground. “Don’t pave over a greenbelt. Let it be there as a sponge so you don’t get as much flooding. Successful adaptation doesn’t mean there won’t be a flood, but it means it will be less severe.”

“Yes, we need to reduce greenhouse gas emissions,” Dr. Krantzberg concluded. “The co-benefit for invasive species is clear. But the climate has changed. We need to adjust to that, and we need to adjust to that right away because the climate’s not going to go back to what it was.”

Lori Thompson, Local Journalism Initiative Reporter, The Manitoulin Expositor