From May to October, thousands of hikers tromp rocky trails lined by tiny cotton thread on the exposed summit of Mansfield, the highest point in Vermont. The mountain is home to a variety of complex ecological landscapes, each determined by elevation and climate.
When taking up an expedition toward the summit, hikers enter a lush green forest dominated by beech and maple trees. They scramble up rocky trails decorated by ferns and mosses and tunneled by foliage.
Then the forest gradually transitions into an array of hardy conifers, the needles of which change the composition of the soil and overhaul the scenery entirely. Near the summit, stunted balsam fir, black spruce, red spruce and heart-leafed paper birch emerge. These trees are dwarf in height, whipped by wind and built to endure below-freezing temperatures.
At the top of the mountain, only shrubbish vegetation can persevere.
This area is an alpine meadow, and it is what biologists call a “rare natural community.” These communities are defined not by the rarity of the species themselves, but by the unique collections of life and geological conditions that, together in their assemblage, are rare, according to Grace Glynn, a Vermont Fish & Wildlife Department botanist.
The vegetation in this alpine meadow has been forming for more than 3,000 years and, in areas, has peat 4-feet deep, she said. Mansfield supports the largest expanse of alpine meadow in the state.
Mansfield is located on the northern half of the spine of the Green Mountains and peaks at 4,393 feet above sea level, according to the Department of Forests, Parks and Recreation.
Unlike surrounding mountain ranges such as the White Mountains and the Adirondack High Peaks — which have several densely located high-elevation summits — Mansfield is isolated in its height from surrounding areas, according to Ryan Rebozo, director of Conservation Science at the Vermont Center for Ecostudies.
This makes Mansfield a sort of island refuge for high-elevation species, Glynn said. It is home to a number of natural communities, some of which are rare or endangered.
Additionally, Mansfield is unique from surrounding mountain ranges because of the type of bedrock it is made of, Glynn said. The stone weathers into soil that’s very acidic, which directly influences plant communities.
The plants on the summit already handle a lot of abuse from high winds, ice needles and trampling by hikers. The Green Mountain Club patrols the summit above treeline to prevent people from degrading the alpine vegetation, according to the club’s Volunteer Coordinator Kate Songer.
But on a larger scale, over the next couple decades, the outlook for those unique alpine populations is bleak, Rebozo said.
Researchers anticipate Vermont will become warmer and wetter as climate change progresses. This change in climate will likely cause low-elevation plants to creep toward higher ground and encroach the territory that alpine shrubs currently dominate, so the forest transitions people see as they hike the mountain will likely change, he said.
As torrential rains flooded much of the state in mid-July, on the mountain, the rain mainly affected trails and the auto road that switchbacks up the mountain, according to Rebozo.
The rest of the mountainside remained more or less unphased by this summer’s storms, as places with vegetation generally hold soil better. But long-term, continued storm patterns will have major impacts, he said.
“The storm is an indication of change,” he said. “It’s one piece of this bigger puzzle of all these stressors to survive. It’s the temperature. It’s the water. It’s the high elevation. It’s everything else.”
Researchers expect a resettling of flora and fauna, he said. Roadside weeds, for example, have already begun to creep up to areas closer to the summit.
But the bulk of change is predicted to take several decades due to the germination cycle of plants. If winters shorten and warm, the plants will experience a longer growing season. This will cause hardwood trees to compete with conifer trees, he said.
This expanse will, as a result, threaten the high-elevation communities, closing in on one of the last places they can exist. Many of the species on Mansfield’s summit are already endangered, including the white flowered diapensia or the waxy-leafed bearberry willow.
A movement upward from low-elevation plants would affect birdlife as well, causing them to breed higher up, Rebozo said. This would again impact endangered birds, such as the Bicknell Thrush, which have historically always had a place in Vermont.
“We’re already starting to see pretty striking declines on some of these high-elevation breeding birds,” Rebozo said. “On places like Mansfield, we’re getting what used to be lower-elevation breeding birds showing up closer to the summit.”
The Bicknell Thrush is a migratory bird that travels from the Caribbean up to Mansfield each year. Its biggest threats are climate change and habitat quality, he said. They are a point of concern because both of their residencies are threatened, as storms also become more frequent and more severe in the Caribbean.
With more research yet to be done, Rebozo said the Vermont Center of Ecosystem intends to focus on insect research on Mansfield to understand the link between animals, bugs and vegetation in the ecosystems that live there.
