Global Climate Change: What do we know? How can we deal with it?

Climate change has always been a part of our landscape: continental glaciers retreated from Vermont only a little over 10,000 years ago. Humans have accelerated the rate of change recently, inducing global warming with so-called "greenhouse gases." Recent estimates by the U.S. Forest Service suggest that as a result of global climate change, Vermont will lose its red spruce and balsam fir, along with other northern species, in the next three hundred years. We don't know what will replace these species, but hopefully we can ensure that southern species of plants and animals can easily migrate north and find suitable habitat by providing an interconnected system of ecological reserves that contain a diversity of physical features from low-lying wetlands to high-elevation cliffs.

Minimum Dynamic Area

Natural communities are maintained by natural ecological processes such as wind, fire, nutrient cycling, flooding, and groundwater movement. Scientists study these natural processes to help them understand how large an area of each community type is needed to maintain all its successional stages and all its inherent variety. Northern Hardwood Forests, for example, naturally occur in large areas, and are influenced by large-scale ecological processes like hurricanes. Scientists with The Nature Conservancy estimate that the minimum dynamic area needed to maintain a healthy, viable Northern Hardwood Forest, with a mixture of old-growth areas and young areas that have resulted from windstorms and other disturbances, is several thousand acres.

Calcareous fens, on the other hand, usually occur as small patches of a few acres, and they respond mostly to local-scale ecological processes like groundwater discharge. A small fen with a small watershed may be adequately protected by just a few tens of acres.

Achieving The Vision: Strategies, Scales, Players

How can we achieve the vision of the Vermont Biodiversity Project? There is no simple answer - as we work toward accomplishing the maintenance of ecological integrity, we'll need to use a variety of tools.

  • We'll need MULTIPLE STRATEGIES, from protecting a system of ecological reserves to changing the way we use resources.
  • We'll need to think, plan, and work at MULTIPLE SCALES, from the individual land parcel all the way up to continental and global scales.
  • We'll need the cooperation of MULTIPLE PLAYERS, from individual Vermonters to state and federal governments.

1. MULTIPLE STRATEGIES

In order to protect Vermont's natural heritage of biodiversity, we will need to employ several strategies on both public and private lands. Four of the key strategies will be:

ECOLOGICAL RESERVE SYSTEM: A system of ecological reserves will be the cornerstone of our effort to protect biodiversity. Reserves are lands that are managed primarily for biodiversity. Typically no resources are extracted from these lands, but some passive recreational use is allowed.

WORKING LANDS: Carefully managed working forests will be crucial in buffering reserve lands from outside perturbations, in providing forested connections between reserve lands, and in otherwise protecting many of the functions of our common forest communities. Carefully managed agricultural lands can provide many benefits to biodiversity if farmers maintain water quality, protect special habitats on their farms, and provide habitat corridors along streams and hedgerows.

REDUCING FRAGMENTATION: Throughout Vermont, we should work to reduce the fragmenting effects of roads by promoting village-based living, cluster development, and public transportation.

REDUCING ENVIRONMENTAL DEGRADATION: Protecting ecological integrity will require improving the quality of our air and water. Although some of the problem originates outside Vermont, we can all participate. For example, individual landowners can help by protecting stream and wetland buffers, and we can all help by reducing our use of resources and by carefully disposing of toxic materials.

The Strategies: Ecological Reserve System

Definitions

An ecological reserve (reserve, core reserve) is a parcel of land that is legally protected and managed primarily for the benefit of biodiversity, or the plants, animals, other organisms, natural communities, physical features, and ecological processes that are naturally found there. Neither timber nor other resources are taken form the land, and natural ecological processes (including fire) are allowed to occur when they do not endanger human life. Recreation may be allowed as long as it are compatible with the primary goal of protecting biodiversity. Typically the recreational activities that are allowed include hiking, hunting, and fishing. Motorized vehicles are generally not compatible with the protection of biodiversity, so they are allowed only when necessary to conduct occasional management activities. An ecological reserve can be owned by any agency, organization, or individual who has the resources and knowledge to manage it properly. Legal protection can take many forms, including ownership by a conservation organization or public agency that is committed to protecting biodiversity in perpetuity and forever wild easements on private land.

An ecological reserve system, or system of ecological reserves, is a group of reserves that taken together will provide much of what is needed to "ensure the long-term viability of all native species within their natural ranges."

Key elements of a reserve system for Vermont

Representation: If a system of ecological reserves for Vermont is to be successful, it must include all native species, all natural communities, and all physical features. Phase I of the Vermont Biodiversity Project identified a set of Biological Diversity Resource Areas (BDRAs) that contain a high percentage of the biological diversity of the state. These areas, along with existing conserved lands, can serve as a starting point for a statewide system of ecological reserves.

Viability: If a system of ecological reserves for Vermont is to be successful, it must also ensure the long-term viability of all native species. There are two key elements to this:

Size: The reserves must be large enough to allow natural ecological processes to take place, and to allow native organisms to move about so they can feed and breed successfully. The science of conservation biology has provided us with the concepts of minimum dynamic area and minimum viable population (see boxes) to help us evaluate what the right reserve size is for protecting the species and natural communities that we care about. For our common natural communities such as northern hardwood forests, The Nature Conservancy estimates that we will need reserves of tens of thousands of acres to adequately protect natural processes. For other natural communities that always occur in small patches (like calcareous fens), reserves on the order of tens to hundreds of acres will be adequate. For certain species with very limited distributions, like a rare plant that only grows on riverside outcrops, very small reserves will be adequate, as long as they can be carefully managed.

Connectivity: A system of ecological reserves must include connections between the reserves in order to ensure that animals and plant propagules can move from place to place to allow for seasonal migrations, genetic exchange, and climatic changes. Phase I of the Vermont Biodiversity Project did not provide specific guidelines for connecting ecological reserves; these guidelines still need to be developed.

The Strategies: Working Lands

A system of ecological reserves will only be successful if the lands surrounding the reserves are carefully managed with biodiversity conservation in mind. We can think of these lands as buffer areas, helping to

  • protect the ecological reserves against outside influences like exotic species and degraded water quality;
  • provide high quality habitat for plants, animals, and natural communities that do not require reserve-quality habitat; and
  • provide connections between the reserves, so that animals and plants can move freely between them.