Climate stressors weigh on New England wildlife

New England has long been known for its four distinct seasons, but as climate change grips the region at a faster rate than in many other parts of the world, this seasonal portrait is being reconfigured and various wildlife species are suffering. the results.

“Climate is a fundamental characteristic of the ecosystem and it can have all kinds of effects on our wildlife,” says Tom Lautzenheiser, senior conservation ecologist for Mass Audubon.

The impact of climate change on a given species depends on various 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 the suitable habitat.

Lautzenheiser said generalist species, those that can take advantage of a variety of food sources and ecosystems, will fare better than specialist species adapted to very specific areas, foods, temperatures and environments. .

For example, species with physiological adaptations to live in snowy and/or cold conditions, migratory species dependent on the seasonal calendar, and specialized species that depend on food resources and narrow habitats are likely to be most negatively affected by warming. temperatures.

Species such as black bears, coyotes, foxes, raccoons and other highly adaptable animals won’t feel the pinch of the weather as much as temperatures rise and habitats change, wildlife experts say.

According to research ecologist Toni Morelli of UMass Amherst’s Northeast Climate Adaptation Science Center, New England is highly susceptible to climate change and is warming at a significantly faster rate than global averages.

Morelli says seasonal patterns are changing, with earlier springs and long dry spells, followed by later falls with intense, torrential rains.

“This is what climate change will look like in the North East,” she said. “On average, we are getting wetter. But we don’t live in averages, we will live in those extremes, and that goes for wildlife too. »

Climate projections show that by the end of the century, the region will have no snow for most of the year, notes Morelli. “It’s a huge change for animals that rely on snow,” she said.

Heat stress, shifts in seasonal synchronicity and habitat destruction affect wildlife, from forests to coastlines and the ocean environment, as climate change forces wildlife species to adapt, alter their range distribution or ultimately to succumb to a warming environment that can no longer support their Needs.

Front line species

Some New England species are outstanding examples of the effects of climate change and how they may interact with existing stressors.

“One of the most striking stories is what’s happening with moose in Maine and New Hampshire,” Morelli said.

Here, climate change has given this tall, long-legged, thick-furred boreal species a punch by creating an inhospitable environment for moose, while also giving rise to a parasite that is decimating its numbers.

“Moose are going through a particularly tough 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 drain the blood of calves during the winter. Surveys reveal that last year there was an approximately 80% mortality rate of moose calves in Maine and New Hampshire.

Morelli says moose in Massachusetts are unaffected by the winter tick, likely due to lower moose population densities, which prevent the tick from being an abundant host.

Yet the climate-induced increase in pests is not the only problem. Moose have a physiological temperature limit and begin to experience heat stress at summer temperatures above 57 degrees and winter temperatures above 23 degrees.

“Now with warmer temperatures, they won’t be able to handle the weather we’re anticipating,” Lautzenheiser said. “They will eventually be kicked out, regardless of the tick problem.”

Like moose, the snowshoe hare is well adapted to living in snowy environments. A master of seasonal camouflage, their summer brown coats shed white during the winter. While the change is triggered by changes in day length, coat color is genetically determined, leaving the hare mismatched in a snow-free environment, making it an easy target for predators.

The Canada lynx is also uniquely adapted to life in cold, snowy environments with its long legs, large paws, and thick coat. Although a decrease in snow cover limits the habitat of the lynx, its survival is also closely linked to the snowshoe hare, which constitutes about 96% of its diet.

Morelli says a lack of snow will also affect some hibernating and ground burrowing animals as they will lose the insulating effect of snow.

“Snowless winters actually mean very cold ground and these species experience much colder environments because of the lack of snow,” she said.

Colder ground means hibernating animals will have to use more of their fat stores to stay warm, further depleting them of insulation.

Some aquatic species also struggle with warming and drought.

“Brook trout are the star child of native cold-water fish struggling with climate change,” Lautzenheiser said.

Brook trout generally cannot tolerate long periods of water temperatures above 68 degrees. Because these fish rely on cold, highly oxygenated water to survive, their populations have been drastically reduced due to rising temperatures and reduced stream flow.

Man-made barriers

Man-made barriers complicate the effects of climate change.

“Rivers are often dissected by culverts or dams, fish populations don’t have the ability to move through those systems to reach the thermal refuge, so they really struggle,” Lautzenheiser said.

Climate change is also having a significant impact on amphibians that depend on vernal pools, unique seasonal pools of water that provide habitat for distinctive plants and animals.

“Vernal pools are home to a number of frogs and salamanders that are forced to breed in these fishless environments,” he said.

However, warmer temperatures and changes in precipitation patterns may cause vernal pools to dry out too quickly for these species to complete their breeding cycles.

“That could really be a problem for a lot of specialized animals like spotted salamanders and marbled salamanders,” he said.

Like moose with the winter tick, amphibians also have an additional parasitic stressor.

“Herpes is in trouble all over the world,” Morelli said, referring to herptiles, or reptiles and amphibians. “We’re worried about frogs and salamanders in the northeast because of diseases like chytrid,” she said.

Chytrid is a fungus that ravages the skin of frogs, toads and other amphibians, eventually killing them.

On the coast, rising sea levels are flooding salt marshes and beaches, threatening species such as swamp sparrows and piping plover.

Piping plovers build nests in the narrow section of land between the high tide line and the foot of coastal dunes, and salt marsh sparrows nest exclusively in a narrow strip of tidal marsh that stretches from Maine to Virginia, with up to half of the world’s population breeding in southern New England.

Morelli says that while beaches and salt marsh areas might naturally regress over time, in many areas there will be no room because humans have built up to the coastline.

“These species will therefore be very vulnerable to climate change as the nests are flooded and the chicks drown,” she said.

“The oceans are also experiencing these major changes and wildlife is certainly responding to them,” Lautzenheiser said. “We are basically seeing massive changes in the ranges of fish and sea life.”

On Cape Cod, Lautzenheiser said, climate change is contributing to the rapid increase in the annual cold stun phenomenon among sea turtles.

As the Gulf of Maine warms at a faster rate than the rest of the world’s oceans, sea turtles are moving further north than in previous years to feed in these warmer waters. By the time they reach Cape Cod on their return south, many find themselves trapped by the arm of the cape as the waters cool there.

“They get tired, and as the season turns, they get knocked out in the cold and wash out with the tide,” Lautzenheiser said. “People bring them to the aquarium some years in the hundreds.”

According to the National Oceanic and Atmospheric Administration, the Northeast has warmed more than any other region in the lower 48 states, exceeding the UN’s threshold of 2 degrees Celsius of warming. The general hypothesis is that the warming of the waters of the Atlantic Ocean contributes to the warming of the coastal and interior areas of the northeast.

“When the global average temperature rises 2 degrees, here in the northeast we will rise 3 degrees,” Morelli said.

Land conservation efforts are one area that could bring some relief to species threatened by global warming.

As scientists study the current impact of climate change on wildlife, they say climate change refuges, or conserving areas that might remain relatively protected from contemporary climate change, may help some species over time.

“There’s been a huge increase in human population over the last century and a huge increase in concrete, invasive plants and insects, temperature changes and changes in rainfall,” Morelli said. “If there are ways in which conservation can 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 to current threats and be successful in adapt.”

Climate Change at Home is sponsored by Whalen Insurance.

Teresa H. Sadler