Habitat Shifts

Many plant and animal species are being found further north and at higher elevations than previously observed. Rising temperatures, changing precipitation patterns and shifts in vegetation communities are changing the effective range and distribution of many native and agricultural species. These habitat shifts impact species and ecosystems.

How are Habitats Shifting?

As temperatures increase, the habitat ranges of many North American species are moving northward in latitude and upward in elevation. While this means a range expansion for some species, for others it means a range reduction or a movement into less hospitable habitat or increased competition. Some species have nowhere to go because they are already at the northern or upper limit of their habitat.

For example, EPA reports that boreal forests are invading tundra, reducing habitat for the many unique species that depend on the tundra ecosystem, such as caribou, arctic fox, and snowy owl. Other observed changes in the United States include expanding oak-hickory forests, contracting maple-beech forests, and disappearing spruce-fir forests. As rivers and streams warm, warmwater fish are expanding into areas previously inhabited by coldwater species. Coldwater fish, including many highly valued trout species, are losing their habitats. As waters warm, the area of feasible, cooler habitats to which species can migrate is reduced. Range shifts disturb the current state of the ecosystem and can limit opportunities for fishing and hunting.

Implications for Land Trusts

Habitat ranges of many plant and animal species will likely continue to shift as temperatures change. While some researchers have created maps showing predictions of the direction in which habitats will migrate based on the speed at which temperatures change in different regions, it can be difficult to determine how, when, and to what extent species will be redistributed.

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While there is much uncertainty regarding habitat shifts, the US Forest Service reports that several groups have been using species distribution modeling (SDM) to predict alteration of habitats under different climate scenarios. These models suggest potential gains as well as losses for some habitats and species, and indicate that species that must travel greater distances to remain in their preferred habitats may face the largest vulnerability without human intervention.  As environmental stewards, land trusts have the opportunity to encourage habitat connectivity to enable terrestrial species to migrate as habitats shift.

Tips for Planning: What Land Trusts Are Doing

Cooperatively Working Towards Conservation Goals.

Land trusts are responding to the potential of shifting habitats in various ways. Some groups are working to expand the connectivity of conserved landscapes to allow for species migration, while others are prioritizing acquisitions of vulnerable areas with exceptional biodiversity to support slower habitat changes.  For example, the Vermont Land Trust worked with land management agencies and biologists to identify and conserve a critical black bear migration corridor between forests of the Taconic Mountains in New York and the Green Mountains. In addition to employing strategic conservation planning to reduce risks and enhance resilience, some land trusts are also supporting efforts to mitigate greenhouse gas emissions to reduce the extent of future climate change.

Land trusts must determine the right planning approach for their organization, however, more and more, conservation organizations are working with their communities to identify opportunities to reduce vulnerabilities and prepare for changing temperatures. Agencies are making similar strides to implement projects that reduce risks and plan for resilience by incorporating adaptation, mitigation, and engagement into their strategic goals and objectives. For example, the U.S. Fish and Wildlife Service’s Strategic Plan for Responding to Accelerating Climate Change identifies seven planning and development goals to support sustainable landscapes. Conservation groups are increasingly partnering with agencies as well as other nonprofits and for-profit organizations to respond to this global challenge at local levels.

Building resilience for multiple management objectives.

Resilience describes the ability of a system to persist through extreme change. By working to identify and reduce potential threats land managers can build resilience and achieve multiple management objectives. Assessing vulnerabilities is a critical step in the strategic conservation planning process that helps land trusts identify key threats to resources. Adaptive management planning enables conservation practitioners to implement interventions to reduce vulnerabilities and to monitor and revise strategies as new information becomes available. There is no one-size-fits-all solution to addressing management challenges associated with warming average temperatures, however, planning that acknowledges vulnerabilities can help land trusts better achieve their conservation objectives.

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