New England has long been known for its four distinct seasons, but as climate change sweeps through the region more rapidly than in many other parts of the world, this seasonal portrait is being reconfigured, and a variety of wildlife species are experiencing the consequences.
“Climate is a key ecosystem feature, and it has all kinds of effects it can have on our wildlife,” says Tom Lautzenheiser, senior conservation ecologist for Mass Audubon.
How a changing climate affects a particular species depends on a variety of factors. These factors may include biology, physical adaptations, diet, reproductive strategies, and interactions with other species, including pests and pathogens, as well as the availability, size, and quality of suitable habitat.
Lautzenheiser said generalist species that can take advantage of a variety of food sources and ecosystems will do better than specialist species that are adapted to very specific areas, foods, temperatures and environments.
For example, species with physiological adaptations to survive in snowy or cold conditions, seasonally dependent migratory species, and specialist species that rely on scarce food and habitat resources are likely to be most adversely affected by warming temperatures.
Wildlife experts say black bears, coyotes, foxes, raccoons and other highly adaptable animals won’t feel the pinch as temperatures rise and habitats shift.
According to Tony Morelli, a research ecologist at the Northeast Climate Adaptation Science Center at UMass Amherst, New England is highly vulnerable to climate change and is warming significantly faster than global averages.
Seasonal patterns vary, Morelli says, with early springs and long periods of drought followed by intense, flooding rains.
“This is what climate change will look like in the Northeast,” he said. “On average, we get wetter. But we don’t live in the middle, we will live in these extremes, and this also applies to wildlife.”
Morelli notes that climate projections show that the region will be snow-free for most of the year by the end of the century. “It’s a big change for animals that depend on snow,” he said.
Heat stress, mismatches in seasonal synchrony, and habitat destruction affect wildlife from forests to coastal and oceanic environments as climate change forces wildlife species to adapt, relocate, or eventually succumb to warming environments that can no longer support their lives. needs.
Some New England species are vivid examples of the effects of climate change and how they may interact with existing stressors.
“One of the most surprising stories is what happened to the moose in Maine and New Hampshire,” Morelli said.
Here, climate change dealt a one-two punch to this large, long-legged, heavy-coated boreal species, creating an unseasonably warm environment for moose and also introducing a parasite that decimated their numbers.
“Moose have a particularly hard time because of the winter tick,” Morelli said, noting that infestations of more than 80,000 ticks have been found on individual moose. These numbers can bleed calves in the winter. Studies show that moose calves in Maine and New Hampshire last year had an estimated 80% mortality rate.
Moose in Massachusetts aren’t affected by the winter tick, Morelli says, likely because moose population densities are declining, denying the tick an abundant host.
Still, climate-related increases in parasitic pests aren’t the only problem. Moose have a physiological temperature threshold and begin to experience heat stress at summer temperatures above 57 degrees and winter temperatures above 23 degrees.
“With the warmer temperatures now, they’re not going to be able to handle the weather we’re expecting,” Lautzenheiser said. “They will eventually be pushed apart from the tick problem.”
Like the moose, the snow hare is well adapted to living in snowy environments. A master of seasonal camouflage, their summer brown coats turn white in winter. Although the variation is caused by changes in day length, coat color is genetically determined, and the rabbit remains inconsistent in a snow-free environment, making it an easy target for predators.
The Canadian lynx is also uniquely adapted to living in cold, snowy environments with its long legs, large paws and thick coat. Although reduced snow cover limits the lynx’s habitat, its survival is closely linked to the snowshoe hare, which makes up about 96% of its diet.
Morelli says the lack of snow will also affect some animals that hibernate and fall to the ground because they will lose the insulating effect of snow.
“Snowless winters actually mean a really cold place, and these species live in colder environments because there’s no snow,” he said.
A cold location means that hibernating animals will have to use more fat reserves to stay warm, further depleting their insulation.
Some aquatic species also struggle with warming and dry conditions.
“Brooke trout are the poster child for cold-water native fish fighting climate change,” Lautzenheiser said.
Brown trout generally cannot tolerate water temperatures above 68 degrees for extended periods of time. Because these fish depend on cold, high-oxygen water to survive, their populations have declined greatly due to rising temperatures and reduced stream flows.
Compounding the effects of climate change are human-made barriers.
“Rivers are often broken up by culverts or dams, fish populations don’t have the ability to get through those systems to get to thermal refuge, so they really struggle,” Lautzenheiser said.
Climate change is also taking a toll on amphibians, which depend on vernal pools, unique seasonal pools of water that provide habitat for a variety of plants and animals.
“Vernal pools are home to a number of frogs and salamanders that are forced to breed in fish-free environments,” he said.
However, warmer temperatures and changes in precipitation may cause vernal pools to dry up too quickly for these species to complete their breeding cycles.
“It can really be a problem for a lot of specialist animals, like spotted salamanders and marbled salamanders,” he said.
Like moose with winter ticks, amphibians have additional parasitic stress.
“Everywhere in the world, herpes is a problem,” Morelli said, referring to herptiles, reptiles and amphibians. “We’re concerned about diseases like chytrid in frogs and salamanders in the Northeast,” he said.
Chytrid is a fungus that destroys the skin of frogs, toads, and other amphibians, eventually killing them.
Along the coast, rising sea levels inundate salt marshes and beaches, threatening species including the sparrowhawk and grasshopper.
Piping plovers build their nests in the narrow area between the high tide line and the foot of the coastal dunes, while salt sparrows nest in a narrow tidal marsh that stretches only from Maine to Virginia, with up to half of the world’s population in southern New England.
Morelli says that while beaches and salt marshes may naturally shift upslope over time, many areas will run out of space as people build up to the shoreline.
“So these species will be very vulnerable to climate change because nests will be flooded and chicks will drown,” he said.
“The oceans are also going through these big changes, and of course the wildlife is responding,” Lautzenheiser said. “We’re seeing mostly wholesale changes in the ranges of fish and marine life.”
On Cape Cod, Lautzenheiser said climate change is contributing to a rapidly increasing annual cold snap in sea turtles.
As the Gulf of Maine warms faster than the rest of the world’s oceans, sea turtles are heading farther north than in previous years to forage in these warmer waters. When they return south and reach Cape Cod, many become trapped in the Cape’s tributary as the waters there cool.
“They get tired, and as the season goes on, they get cold-stunned and washed away on the tide,” Lautzenheiser said. “People bring them to aquariums by the hundreds every few years.”
According to the National Oceanic and Atmospheric Administration, the Northeast has warmed more than any other region in the Lower 48 states, surpassing the UN’s 2 degrees Celsius warming limit. The general hypothesis for this is that warming waters in the Atlantic Ocean contribute to warming along the Northeast coast and inland.
“When the global average temperature rises by 2 degrees, here in the Northeast we will rise by 3 degrees,” Morelli said.
Soil conservation efforts are one area that can provide some relief for species threatened by a warming climate.
As scientists examine the current effects of climate change on wildlife, they say climate change refuges, or protecting areas relatively buffered from modern climate change, may help some species over time.
“In the last century, there has been a huge increase in human population and a huge increase in concrete, invasive plants and insects, temperature changes and precipitation,” Morelli said. “If conservation has ways to reduce some of these stressors, then species that have been around for millions of years and have adapted and evolved to threats can potentially respond and adapt to existing threats.”
Climate Change at Home is sponsored by Whalen Insurance.