Silvio O. Conte National Fish and Wildlife Refuge
|Silvio O. Conte National Fish and Wildlife Refuge|
IUCN category IV (habitat/species management area)
|Location||Connecticut, Massachusetts, New Hampshire, Vermont, United States|
|Area||31,216 acres (126.33 km2)|
|Governing body||U.S. Fish and Wildlife Service|
Silvio O. Conte National Fish and Wildlife Refuge was established in 1997 to conserve, protect and enhance the abundance and diversity of native plant, fish and wildlife species and the ecosystems on which they depend throughout the 7,200,000-acre (29,000 km2) Connecticut River watershed. The watershed covers large areas of Vermont, New Hampshire, Massachusetts and Connecticut. It contains a great diversity of habitats, notably: northern forest valuable as nesting habitat for migrant thrushes, warblers and other birds; rivers and streams used by shad, salmon, herring and other migratory fishes; and an internationally significant complex of high-quality tidal fresh, brackish and salt marshes.
The refuge works in partnership with a wide variety of individuals and organizations to provide environmental education, to encourage and support appropriate habitat conservation and management on public and private lands, and to protect additional habitat.
The refuge has three cooperative visitor centers: in Colebrook, New Hampshire; at the Montshire Museum of Science in Norwich, Vermont; and Great Falls Discovery Center near the headquarters in Turners Falls, Massachusetts. The refuge currently consists of seven units (small tracts) and two divisions (large tracts): 33 acres (13 ha) of wetlands and a riverine sand spit that hosts a federally listed beetle in Cromwell, Connecticut; a 4-acre (1.6 ha) island in Deerfield, Massachusetts; 30 acres (12 ha) at the base of Mount Toby in Sunderland, Massachusetts; an 18-acre (7.3 ha) upland and wetland parcel in Westfield, Massachusetts; 140 acres (57 ha) on Mount Tom in Holyoke, Massachusetts; 20 acres (8.1 ha) along the river in Greenfield, Massachusetts; 278 acres (113 ha) which host a federally endangered plant in Putney, Vermont; 1,023 acres (414 ha) on the Mohawk River in Columbia, New Hampshire (the newest division, which opened in 2007); 3,670 acres (1,490 ha) surrounding the Audubon Society of New Hampshire's Pondicherry Refuge in Jefferson, New Hampshire; and 26,000 acres (11,000 ha) in the Nulhegan Basin in Essex County, Vermont.
People have spread species from one geographic area to another throughout history, inadvertently as well as purposefully. Usually, this does not create a problem. However, there are a small percentage of species, that when removed from the insects, diseases, and competing species that control their numbers in their native area, become established, spread rapidly, displace native species, and may even change the way an ecosystem works.
Only a small number of the thousands of species that have been either purposefully or accidentally introduced into the watershed have the potential to become, or have already become, invasive. However, when certain species are introduced from other places and find conditions favorable, they may be able to out-compete native species, especially if they have no predators adapted to control them in their new location. Many of these species were first introduced specifically because they were easy to establish, hardy and disease resistant. In addition to the initial introductions, human activities can favor the spread of many of these species. When a species can spread into natural communities, become established, displace native species, and cause ecological and economic damage, it is said to have become invasive.
These "invasive" species pose a great threat to the native biodiversity this refuge was established to protect, so refuge staff are very active in educating the public and specific target audiences about the issue. They work on early detection and rapid response and control projects.
Although some birds and mammals have been introduced, fish and plants have been the most common introductions. According to Bickford and Dymon (1990), 950 of the 2,700 plants in Massachusetts have been introduced. Problems are being caused by invasive plants throughout the watershed. Although common reed (Phragmites communis) and purple loosestrife (Lythrum salicaria) degrade wetlands throughout the watershed, these two plants seem much more widespread in Connecticut, affecting a great number of wetland acres there. Another plant affecting both wetland and upland habitats in Connecticut is Japanese stilt grass (Microstegium vimineum). Oriental bittersweet (Celastrus orbiculatus), Japanese knotweed (Polygonum cuspidatum), multiflora rose (Rosa multiflora), buckthorns (Rhamnus cathartica and Rhamnus frangula), and Japanese barberry (Berberis thunbergii) are widespread in upland areas, with the knotweed extending into New Hampshire and Vermont. Eurasian milfoil (Myriophyllum spicatum) is a problem in many ponds and lakes in the watershed.
Non-indigenous fish species are found throughout the length of the Connecticut River and its tributaries. There are more introduced fish species in the watershed than there are native species. Of the freshwater fish species found within the watershed, there are 33 native or indigenous freshwater species and 35 non-indigenous. Many species were introduced in an effort to provide recreational fisheries, specifically trout, bass, pike and sunfish. Native species populations were reduced because of exploitation, habitat loss, and water quality degradation. Land management practices including forestry and dairy and truck farms, damming for industry, and industrial discharges have resulted in altered habitat and water quality conditions that were better suited for non-indigenous species.
The distributions and populations of fish are better known than those of any other aquatic species. The state fishery and heritage agencies are working together to avoid the loss of native fish species as a result of the purposeful or accidental introduction of non-native fish and plant and animal species.
Asiatic clam (Corbicula fluminea) is a freshwater clam that first entered North America in the early 1900s, reaching the mid-Atlantic states in the 1970s and 1980s. The animal obtains a size of approximately one-half inch as an adult. The Asiatic clam has been identified in the lower reach of the Connecticut River. It is of great concern because it has an extremely high reproduction rate, an average of 70,000 offspring per adult per year. It is of great economic concern because of its ability to clog industrial water intake pipes. It is a serious environmental threat to the ecosystem because it will displace native mollusk species. It has the potential to greatly disrupt native fish and other aquatic animal and plant species both because of the physical presence of the clams, which achieve a high density (10,000 to 20,000 individuals per square yard), and its effect on the food web.
Zebra mussels (Dreissena polymorpha), although not yet present in the Connecticut River system, could do very significant harm to native freshwater mussels. The animal obtains a size of approximately ½ inch to 1½ inches as an adult. It is of great concern because, similarly to the Asiatic clam (above), it has an incredible propensity to reproduce. It is also of great economic concern because of its observed ability in the Great Lakes and elsewhere to clog water intake pipes of waste water treatment plants, electric generation plants, and industrial operations. It is a serious environmental threat to the ecosystem because it will displace native mollusk species. It has the potential to greatly disrupt native fish and other aquatic animal and plant species as a result of its physical presence and its effect on the food web. Because of the massive populations rapidly produced by the mussels, they filter from the water vast amounts of algae, phytoplankton, and zooplankton. This eliminates or greatly reduces the food supply for other organisms.
The population of Mute swans (Cygnus olor) is increasing in Connecticut. They cause damage to plants which provide food for other waterfowl and they outcompete native waterfowl for nesting habitat.
Introduced forest pests
Introduced forest pests are also a huge problem. Gypsy moths have caused widespread damage over the years. In addition, attempts to control them have severely affected non-target native species. DDT spraying for gypsy moth control in the 1950s and 1960s severely depressed the populations of many butterflies and other insects.
The woolly adelgid, an introduced aphid (Adelges tsugae), is presently killing hemlock trees, often found on steep slopes near the rivers in Connecticut, posing potential erosion problems. Diseases, such as chestnut blight, Dutch elm disease, and a fungus affecting butternut trees, also have major effects on species and the makeup of natural communities.
- Great Northwoods Interpretive Center of the Silvio O. Conte National Fish and Wildlife Refuge 
- Mohawk River Division of the Silvio O. Conte National Fish and Wildlife Refuge 
- Pondicherry Division of the Silvio O. Conte National Fish and Wildlife Refuge 
- Nulhegan Division of the Silvio O. Conte National Fish and Wildlife Refuge