Species Need Habitat Restoration to Survive a Changing Climate

By Kevin Bunch, IJC

frogs climate change
Spring peeper frogs may find their spring mating calls disrupted due to climate change. Credit: Brad Carlson

Human development has fragmented natural environments across the Great Lakes basin, causing problems for species that rely on those habitats to survive. These problems may be exacerbated by a changing climate. This hasn’t snuck up on the people and organizations working on restoring habitat and connectivity though – climate change has been at the forefront of their planning for nearly a decade.

On the United States side of the Great Lakes, funding through the Great Lakes Restoration Initiative (GLRI) has helped support habitat restoration efforts for the past seven years. The US National Oceanic and Atmospheric Administration (NOAA) has used GLRI funding to assess how climate change might affect habitat restoration and protection efforts. Groups applying to receive GLRI funds for habitat restoration should consider how climate change might impact their work in the future, said Heather Braun, program manager for coastal conservation and habitat restoration at the Great Lakes Commission in Ann Arbor, Michigan.

“Project applicants have a variety of resources to look to for guidance of developing ‘climate-smart’ projects,” Braun said.

What’s challenging is the uncertainty of the future; some models say water levels may increase and others say they may decrease, so restoration projects should be designed to accommodate both possibilities. For example, Braun said a wetland restoration project might include a provision for a water control station or water pumping station to allow the wetland to continue functioning in a low-water future. Restored habitats also need to be able to withstand increased intensity of storms: high winds, strong waves, seiches (or waves pushed from one end of a body of water to another) and ice.

Reducing habitat fragmentation is an important part of restoration work, and for the GLRI. Braun said special consideration has been given to projects that are adjacent to one another to improve connectivity – particularly in Michigan’s Saginaw Bay and Ohio’s Maumee Bay. With a changing climate, a variety of plants and animals will be seeing their habitable ranges change – connectivity can improve their chances to live in areas they can survive.

According to the 2013 Environment and Climate Change Canada report, “How Much Habitat is Enough?,” species across North America are already responding to climate change with shifts in ranges, longer stays in breeding grounds by some birds, and earlier mating calls by amphibians. But with the complexity of species, their specific needs, and environments, it’s incredibly difficult to determine what effects will be coming down the line for specific regions and habitats.

The report suggests a precautionary approach that would protect and restore more complete ecosystems beyond the minimum amount of forest, wetland, grassland and riparian areas needed to maintain species populations above an extinction level threshold. A more connected and less fragmented ecosystem is more resilient to climate change, the report says.

Setting aside habitat fragmentation, there would ostensibly be greater biodiversity as a result of global warming in more northern regions like Ontario, said Jeff Bowman, research scientist with the Ontario Ministry of Natural Resources and Forestry, and faculty at Trent University. But habitats fragmented by human development in areas along the Great Lakes – such as the coastal marshlands of the Huron-Erie corridor – would inhibit movement north, which will likely result in less biodiversity than would otherwise be expected.

While the Great Lakes serve as a natural barrier for some of this movement, Bowman said, animals can still cross in some key areas like connecting channels. Animal crossings can occur in the Rainy River system west of Lake Superior, the St. Marys River, the western and eastern connecting channels of Lake Erie, and the east end of Lake Ontario, Bowman said.

Landowner initiatives can provide important safeguards, such as the A2A Collaborative in New York, Ontario and Quebec. The collaborative is working on a wildlife corridor between Algonquin Provincial Park in Ontario and Adirondack Park in New York, including Thousand Islands National Park in the St. Lawrence River. Species have historically used this route to travel north and south across the North American continent. Having a stable connection across latitudes and habitats can shore up the resiliency of biological populations in the face of climate change, according to the project website.

A2A map
Map of the A2A Region. Credit: Algonquin to Adirondacks Collaborative

The northward expanded range of animals such as southern flying squirrels and bobcats into northern ranges is forcing them to interact with similar existing species. Already, Bowman said, there are reports of hybrids between the southern and northern flying squirrels in Ontario, and there are concerns that bobcats expanding their range north might hybridize with lynx.

“Hybridization is one of the predicted effects of climate change,” Bowman said. “And the flying squirrels are one of the first demonstrated examples of what we call climate change induced hybridization.”

There’s also a disconnect between how quickly animals can move into new areas and how slowly plants do. Bowman said that southern flying squirrels are, for example, getting ahead of trees they live alongside and are thus unable to find the acorns to eat that they rely on in their southern ranges – in turn causing them to die in the winter. So even though the squirrels could find pleasant temperature ranges and some food in their new homes, they ultimately must wait for the trees they rely on to permanently settle in these new regions.

flying squirrel
Due to climate change, the southern flying squirrel has started moving north into habitat already occupied by the northern flying squirrel. Credit: North Carolina Wildlife Resources Commission

Bowman added that some amphibians seem to be taking advantage of the expanding breeding season by emitting mating calls earlier in the year, potentially allowing them a competitive advantage for food supplies over their rivals that must wait.

Habitat restoration project managers need to balance near-term restoration goals with an increasingly variable climate and consider what species will be well-placed to survive in in the future. This includes anticipating the spread of invasive species and planning for long-term management, Braun said.

Invasive species such as Phragmites thrive on habitat disturbances and low water levels, Braun said. Anticipating such changes and improving coordination of invasive species management efforts is important to reduce encroachment on newly restored areas or in existing habitats stressed by climate change, disturbance or fragmentation already. The species’ almost virulent spread and rapid infestation rate makes that a challenge, leading to a push to track its spread and coordinate efforts across the Great Lakes.

Improving coastal resiliency to climate change  for the Great Lakes basin is an ongoing effort for all the states and provinces around the waters. Improvements done thoughtfully would make the challenges down the line more manageable.

Kevin Bunch is a writer-communications specialist at the IJC’s US Section office in Washington, D.C.

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