Balancing trade-offs between carbon storage and wildlife habitat

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Vermont Business Magazine University of Vermont (UVM) researchers see a mosaic of diverse forest habitats, or patchwork, as a way to create a resilient landscape better suited to climate change.

“The importance of the diversity of habitat conditions across the landscape may be increasingly overlooked, especially by the public, as forest carbon storage takes center stage,” said lead author Caitlin. Littlefield, recently a research associate at the UVM Rubenstein School of Environment and Natural Resources (RSENR). “As more attention is paid to maximizing forest carbon, we risk unwittingly compromising the long-term sustainability of other goals, such as maintaining important habitat for wildlife species at risk.”

In a new article published in Conservation science and practice, Authors Littlefield, now a senior scientist at Conservation Science Partners, and RSENR Professor Anthony D’Amato, recommend practicing forest management with a climate-adaptive lens to help sustain forests for carbon benefits while providing a wildlife sanctuary. Adaptation to climate change prioritizes the diversity, complexity and connectivity of landscapes.

The authors examined four types of forest and open woodland habitats in the northern half of the United States. This region transitions from the hardwood forests of New England and the spruce-fir forests farther north to the grasslands and oak savannahs of the Midwest and the sandy pine barrens of the coastal northeast. These habitats support one of the greatest faunal diversities in the temperate zone, between the tropics and the Arctic.

After the ice receded, natural disturbance agents (beavers, floods, wind, hurricanes, ice, and fire) along with Indigenous peoples maintained open meadows, shrubs, and early successional habitats scattered across the otherwise forested landscape . Today, many of these open habitats have begun to convert to late successional conditions due, in part, to fire exclusion, beaver trapping, flood dams, and insect suppression. . The disappearance of small to medium-scale natural disturbances has contributed to the homogenization of forests throughout the region.

In each of the four ecosystems, the authors found that managing only mature stands of trees does not provide critical habitat for sensitive wildlife species. Restoring these four habitats across the vast landscape will support biodiversity, increase resilience to change, and could ultimately store more carbon over time by resisting carbon loss from catastrophic disturbances such as severe wildfires. and drought-induced stress on trees. Restoring these habitats often involves the reintroduction of natural disturbances and practices such as controlled burning.

“Characterizing the trade-offs and consequences of alternative management options can help avoid practices that can ultimately reduce the complex ecological structure of forests and their ability to adapt to change,” said D’Amato, director of the forest program at UVM. “This kind of critical assessment of management actions at the forest stand level can then facilitate landscape-scale planning that supports a diversity of habitats while also suggesting where we should invest to maximize forest carbon. ”

Early successional habitat in the hardwoods of northern New England

There are currently fewer early succession forests – and fewer old-growth forests – throughout New England since forests rebounded from clearing by European settlers. Wildlife species dependent on early successional habitat have declined, including American woodcock, ruffed grouse, and especially breeding songbirds.

The Golden-winged Warbler has experienced one of the steepest declines of any North American songbird. The bird nests near the ground in early successional patches of two and a half acres or more and often depends on the surrounding mature forest for food.

“Fauna that require early successional habitats in the Northeast include nearly 90 different species of birds, mammals, reptiles and insects, many of which are ‘species most needed for conservation,’ said Jim Oehler, wildlife habitat program supervisor for New Hampshire’s Fish and Game Department, “Strategic, carefully planned and executed forest management is essential to restoring and maintaining healthy populations of these species, especially in light of climate change.”

Compared to mature forests, early-successional forests store less carbon overall, but they sequester, or capture and store, carbon at relatively high rates. This, combined with a mix of wildlife habitats across the landscape, would offset the trade-off of not pursuing maximum carbon storage.

“This document affirms the value of conserving and maintaining a range of forest conditions, including early succession forests, on public and private lands and reinforces the importance of not focusing on a single objective, such as just maximizing on-site carbon storage,” said Michael Snyder, Vermont Commissioner of Forests, Parks and Recreation. “As this work and initiatives such as Vermont Conservation Design demonstrate, wildlife habitat restoration and active forest management are becoming increasingly essential for conserving and connecting a diversity of habitat types in the landscape of New England.”

Open wooded and grassy habitats

Three open forest ecosystems – the tallgrass aspen parklands of northern Minnesota, the oak savannahs of southern Michigan, and the coastal pine barrens of the northeast – are other examples of critical habitats that are shrinking in the region. . The exclusion of natural fires has allowed the encroachment of less fire resistant invasive tree and plant species and a loss of open conditions, patchy vegetation and native plants essential for many vulnerable wildlife species.

In addition to reducing important habitat conditions for wildlife species at risk, the increase in the number of less fire-tolerant trees and shrubs makes forest stands more vulnerable to drought and pests and increases the severity of fires, which can release a large amount of carbon. By restoring low severity, prescribed fires help to alleviate drought stress, reduce encroaching vegetation, restore critical wildlife habitat, and prevent higher severity fire hazards, further driving people away. carbon from the atmosphere.

In a conservation success story, resource managers are restoring and maintaining Minnesota’s tallgrass aspen parklands through mowing, tree harvest openings, and prescribed burns. These strategies favored the return of elk populations after regional extirpation in the early 20and century. Sharp-tailed grouse and sandhill cranes have also largely recovered from dramatic declines.

“It is essential to recognize that climate change itself is one of the most serious threats facing wildlife in this region and the world,” Littlefield said. “We don’t have the luxury of unlimited time to design the ‘perfect’ balance between maximizing carbon storage and wildlife habitat across the landscape. Assessing vulnerabilities and risks, recognizing trade-offs, and prioritizing ecological complexity and landscape heterogeneity may well be the best way to keep carbon out of the atmosphere while protecting wildlife and hedging our bets. in an uncertain future.

The researchers’ work is supported by the Northeast Climate Adaptation Science Center, which is operated by the US Geological Survey’s National Climate Adaptation Science Center.

Source: 4.11.2022. BURLINGTON, Vermont — University of Vermont

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