7. INTERNATIONAL AND NATIONAL IMPORTANCE:

A. Tidal Marshes: The most distinguishing and ecologically important feature of this complex is its extensive system of high quality freshwater and brackish tidal marshes that serves as essential habitat for a number of regionally, nationally, and globally rare or otherwise significant species. The flowing waters and shallow water habitats of the river itself also provide the essential linkage among all the marshland units in this complex. In addition, they are of vital importance to a number of finfish species, especially anadromous fish including the federally-endangered shortnose sturgeon (Acipenser brevirostris) and the Atlantic salmon (Salmo salar); the latter has been petitioned for listing under the U.S. Endangered Species Act and is the subject of extensive state and federal restoration efforts in New England. From a regional standpoint, there are no other areas in the Northeast that support such extensive or high quality fresh and brackish tidal wetland systems as do those in the Connecticut River estuary. The marshes here are probably the best example of these types of marshes anywhere in the northeastern United States, far better than similar types of marshes on the Hudson, Housatonic, and Merrimac Rivers. Wild rice is an especially important and characteristic species of these marshes, but they are also characterized by a high species diversity of both plants and animals. For example, within the project area there are 17 plant species in the salt marshes, 36 in the brackish marshes, and over 150 in the freshwater tidal marshes (Barrett 1989). Those characteristics of this complex of tidal marshes that contribute most to the area's overall significance are:

1) Tidal freshwater and brackish marshes in this region are far more diverse in species and structure than salt marshes, which contributes to their greater use by fish and wildlife of all types;

2) They are critical habitats for a variety of rare plants and animals, e.g., bald eagle (Haliaeetus leucocephalus), osprey (Pandion haliaetus), black rail (Laterallus jamaicensis), least bittern (Ixobrychus exilis), northern harrier (Circus cyaneus), American bittern (Botaurus lentiginosus), northern diamondback terrapin (Malaclemys t. terrapin), golden club (Orontium aquaticum), and Parker's pipewort (Eriocaulon parkeri) (see Section D and Appendix D);

3) Habitat diversity throughout the complex is exceedingly high, with no two marshes being identical, owing in part to the pronounced and rapid change of the salinity/vegetation gradient over short distances;

4) Wild rice marshes in the lower Connecticut River are an outstanding and extremely well-developed representative of this wetland habitat type in the Northeast and are biologically important as resting and feeding areas for migratory waterfowl, shorebirds, and rails. These areas are especially important migratory habitats for American black duck (Anas rubripes); and

5) Productivity in these freshwater and brackish tidal wetlands is exceptionally high. Aside from the marshes themselves, the waters, tidal flats, and river bed of the Connecticut River are important finfish and shellfish areas, especially for anadromous fish such as Atlantic and shortnose sturgeons (Acipenser oxyrhynchus and A. brevirostrum), Atlantic salmon (Salmo salar), American shad, and blueback herring (Alosa aestivalis), as well as for American oyster (Crassostrea virginica) and soft-shelled clam (Mya arenaria).

B. Migratory Species: The linear, interconnected riparian and riverine system that the lower Connecticut River provides is important as a migratory corridor for many species of anadromous and catadromous fish, including American shad, river herrings, Atlantic salmon, shortnose and Atlantic sturgeon, American eel, and sea lamprey (Petromyzon marinus), many of which migrate upstream into Massachusetts and northern New England through an extensive biological corridor that links marine and estuarine waters of the Atlantic Ocean with freshwaters of cool, inland streams.

The Atlantic salmon is an anadromous species that depends on unpolluted, high quality riverine habitat for spawning. Spawning takes place in late October or November, and the newly hatched fish emerge in late March or April of the following year. These fish grow as they feed on the variety of food available to them in the river and spend from 1 to 2 years in the river growing to approximately 15 centimeters (6 inches) in length. In the spring of their second year they change physiologically to adapt their bodies for living in salt water and begin their migration downstream to the ocean. During the oceanic phase of their life history these fish migrate to the rich feeding areas in the North Atlantic Ocean near Greenland where for 1 to 3 years they grow rapidly and mature to a fish of 0.1 to 0.2 kilograms (8 to 15 pounds). In the early spring adult fish migrate to their home river, arriving from May onwards to start their cycle of life again. Unlike other salmon, after spawning these fish may return to the sea again as "kelts" to feed and grow larger and return a second or third time to spawn. The lower river is an especially important area for both young fish migrating to the ocean and returning adults.

The lower Connecticut River valley is also an important movement corridor for migratory birds, especially waterfowl, rails, many species of Neotropical migrants, and raptors, that annually use this area during the spring and fall migration periods as a migration pathway north or south through the region en route to breeding or wintering grounds. Many bird species also nest in the project area or spend the winter in the marshes. Some species, such as the American black duck, use the lower Connecticut River as breeding, wintering, and migration areas.

The Connecticut River valley as a whole is an important navigation and migratory stopover for numerous waterfowl, wading birds, and shorebirds. Within the project area itself, the combination of diverse and abundant wetland types, extensive intertidal flats, a wide range of salinity gradients, and relatively low human disturbance attracts a high diversity and substantial number of waterbirds. The abundance of wild rice marshes in the project area provides an especially important food resource for waterfowl and rails.

The lower Connecticut River regularly supports over 10,000 individuals, principally wintering birds, consisting of 18 species of waterfowl, including dabbling ducks, diving ducks, mergansers, and geese. The primary waterfowl that use this area, listed in decreasing order of abundance, are: American black duck, mallard (A. platyrhynchos), blue-winged teal (A. discors), and green-winged teal (A. crecca).

The area is especially important for American black duck. During the migration and wintering periods, the most important habitats for black ducks in southern New England are the tidal wetlands of the Connecticut River and tidal wetlands, bays, and mudflats along the coast (Merola and Chasko, 1989). Black ducks originating in Canada and northern New England rest and feed here during migration. The river provides open-water wintering habitat at a time when much of the inland freshwater areas are frozen over. The Connecticut River wetlands have been identified as regionally important black duck habitat under the North American Waterfowl Mangement Plan.

Three species of rails are regularly found as nesters and migrants in the project area: sora (Porzana carolina), Virginia rail (Rallus limicola), and clapper rail (Rallus longirostris). Also present are king rail (Rallus elegans) and black rail as rare nesters and migrants. Sora are especially abundant in the fall and are concentrated in the wild rice marshes.

The intertidal mudflats and shores associated with freshwater brackish marshes and high salt marshes around the mouth of the river are especially attractive to migratory shorebirds. The area regularly supports a minimum of 5,000 individuals, composed mostly of 9 species, though about 30 species can be found here. The most abundant species are black-bellied plover (Pluvialis squatarola), semipalmated plover (Charadrius semipalmatus), greater yellowlegs (Tringa melanoleuca), lesser yellowlegs (T. flavipes), and semipalmated sandpiper (Calidris pusilla). These species are commonly observed resting and feeding along the shoreline and on the marshes and mudflats during the migration periods of late spring and late summer.

There is a considerable diversity of summer avifauna in the project area; a significant percentage is composed of Neotropical migratory landbirds. This is a large and diverse group of birds consisting of many unrelated families and species that are linked primarily on the basis of a single criterion: they all breed in the North American temperate zones and migrate south of the continental United States during non-breeding seasons. As a group they have been receiving a great deal of attention in recent years owing to the fact that a number of them have been experiencing long-term declines, some rather seriously.

Craig (1973) surveyed the summer avifauna of most of the core wetlands in the project area and recorded the presence of 142 species (see Appendix C). These can be categorized as follows:

• wetland species - 42;
• upland border species - 73;
• migrants - 31.

Forty-two species, approximately 46 percent of the all species observed in Craig's study, are classified as Neotropical migrants. Twenty-one of these, or 50 percent of the Neotropical migrants, have been determined recently to be experiencing statistically significant declines in the Northeast (Smith, et al., 1993). In a separate analysis, data available from the breeding bird atlas project for Connecticut (Bevier, 1994) was analyzed to determine summer bird use in the vicinity of the project area and revealed that 134 species of birds are known to breed (106) or possibly breed (28) within the boundary of the project area. In this group, 76 species, or 57 percent, can be classified as Neotropical migrants. Nineteen of these species, or 25 percent of the Neotropical migrants, are currently undergoing statistically significant declines in the Northeast (Smith et al., 1993). Thus, the project area provides important nesting habitat for approximately 20 species of seriously declining Neotropical migrants.

C. Unfragmented Habitat: The lower Connecticut River corridor and its complex of wetlands provides a linear system of relatively undisturbed and contiguous wetland and upland habitats that is especially important to species that are sensitive or vulnerable to habitat fragmentation through loss of intervening essential habitat and buffers. This is particularly significant to species that occur naturally in small localized populations, such as piping plover and least terns, but which are nonetheless highly dependent on interactions among other local populations in a region for alternate breeding sites, gene flow, recolonization, stepping stones, etc.. These local population assemblages of interactive and interdependent populations within an area are referred to as metapopulations. Maintenance of linkages among local populations of species in a metapopulation is essential to the long-term survival of such species within this region. Unbroken, contiguous habitats are also important to species such as forest interior breeding birds, particularly Neotropical migrants (discussed above), that are sensitive to "edge effects" produced by fragmented forests and other landscapes which render such species populations vulnerable to increased predation, parasitism, and other adverse effects.

D. Rare and Endangered Species: The Connecticut River watershed as a whole is remarkable in the region for the number of rare or endangered species that occurs there, but there are few areas in all the Northeast that contain such a high concentration of rare, declining, or protected species as does the lower Connecticut River near its mouth. A large number of these species is legally protected by the federal government and the state of Connecticut under their respective endangered species statutes (see Appendix D). In 1990, the U.S. Fish and Wildlife Service conducted a Congressionally-mandated study of regionally significant habitats along the coast of southern New England and Long Island, New York; this study focused primarily on those habitats of importance to Federal trust species, i.e., U.S. endangered/threatened species, migratory birds, anadromous fish, and marine mammals (U.S. Fish & Wildlife Service 1991). The study identified the lower Connecticut River and its associated tidal marshes as a regionally significant habitat complex based on the area's extraordinary habitat quality and its importance to Federal trust species, especially rare and endangered species. Among the 40 significant habitats identified in the study, the lower Connecticut River complex emerged as superior on the basis of rare species concentrations and species diversity. The report concluded that this area should be considered for listing under the Ramsar Convention.

In 1991, the Service was directed by Congress as part of the Conte National Fish and Wildlife Refuge authorization and planning study to undertake a study of the fish and wildlife resources of the entire Connecticut River watershed, from its headwaters near the Canadian border to its mouth at Long Island Sound, a distance of 660 kilometers (410 miles) and encompassing a watershed of over 2.9 million hectares (7.1 million acres). In addition to Federal trust species, this study also focused on many state-listed species and regionally rare species of fish, wildlife (including invertebrates), and plants, over 600 species in all. As in the earlier coastal study, the mouth of the river and its tidal marshes showed exceptional clusterings of state, regionally, nationally, and globally rare and/or endangered species.

Of special prominence in the lower river are wintering bald eagles (Haliaeetus leucocephalus), nesting osprey (Pandion haliaetus) (see below), shortnose and Atlantic sturgeon, piping plover (Charadrius melodus), northern diamondback terrapin (Malaclemys t. terrapin), several species of rare plants, Puritan tiger beetle (Cicindela puritana), colonial waterbirds, rails, and other species of regional management concern. The tidal marshes and forested areas along the river and many of its islands are major bald eagle concentration areas for feeding during the winter and osprey concentration areas for both nesting and feeding. This area is rapidly becoming an important viewing area for both these birds in the northeastern United States, especially for wintering bald eagle. Eagles formerly nested in this area as late as the 1950's, and there is optimism that nesting will be reestablished in the near future, as several adult bald eagles have been observed during the summer months. Harbor seals (Phoca vitulina), too, are becoming more common in this area of late. The area is also one of the most important shortnose sturgeon sites in the region, both for spawning and feeding, and is the site of Atlantic salmon releases and restoration efforts. A complete listing of federal- and state-listed species and candidate species occurring in the project area is provided in Appendix E.

A species of particular importance in the project area is the osprey. While the area contains the highest concentration of breeding ospreys along this section of the southern New England coast, current numbers of osprey are still only a shadow of their former abundance. In the late 1930's and early 1940's, there were approximately 200 nesting pairs of ospreys at the mouth of the Connecticut River. While nest sites were primarily in trees, ground nesting was known to occur on islands in the river mouth such as Great Island. This species experienced a long-term decline due to reproductive failure resulting from biomagnification of break-down products of the pesticide DDT. Populations steadily declined to only a few pairs by early 1960. Subsequently, the populations began a gradual increase as a result of the ban on the use of DDT. In 1994, there were 29 nesting pairs in the lower river; this represents only 14 percent of the 1930-1940 population. Recently, a small, short-term decline has been documented in the Connecticut River population, the significance or cause of which is not known.

E. Submerged Aquatic Vegetation: Submerged aquatic vegetation (SAV) is a highly important food source and shelter for many species of birds, finfish, and shellfish, but very little is currently known about its status or long-term trends in the Connecticut River. It is surmised that SAV declines occurred prior to the water quality restoration efforts that commenced in the 1960's. In an attempt to gather more information on this ecologically important resource, the Connecticut Department of Environmental Protection provided a Long Island Sound Research Grant in the spring of 1994 to The Nature Conservancy to map the SAV beds in the project area. The results of this study will be compared to a descriptive survey of SAV species and distribution conducted in the 1940's (Hotchkiss 1947) by the then Connecticut Board of Fisheries and Game to establish a baseline of information from which to assess the SAV beds' future status and trends.

F. Fisheries: Like Long Island Sound, a nationally recognized estuary, the lower Connecticut River is also an estuary, or mixing zone of fresh and saline waters. As such, it is characterized by estuarine dependent fish, shellfish, bird, and invertebrate species. Estuaries are important nutrient traps, which makes them especially productive and important fish nursery habitats. The greatest diversity of fish species in the region occurs in this area due to the presence of freshwater, estuarine, and marine fish that utilize the tidal river and shoals at the river mouth in Long Island Sound at various times of the year.

The marine fish community is comprised of over 25 species that commonly use the estuary and an additional 25 species that occasionally use the area. Of these, winter flounder, summer flounder, striped bass, and bluefish are commercially and recreationally important. Most notably, the estuary provides significant spawning habitat for the winter flounder, a species whose coast-wide stocks are decreasing. The extreme abundance of marine fish and invertebrates adds immensely to the productivity of the overall system by providing a forage base of substantial proportions for piscivorous (fish eating) fish and birds, including several rare and endangered species of birds. The highly abundant bay anchovy (Anchoa mitchilli), Atlantic silverside (Menidia menidia), killifish (Fundulus spp.), and American sand lance (Ammodytes americanus), as well as grass shrimp (Palaemonetes pugio) and bay shrimp (Crangon septemspinosa) form the foundation of this highly productive system.

Similarly, freshwater fishes in the project area are both abundant and diverse. With over 28 species known to occur in the project area, the lower Connecticut River supports the most diverse freshwater fishery in New England. Northern pike, largemouth and smallmouth bass, yellow perch, and channel and white catfish comprise the bulk of the recreational fishery and, to a lesser extent, the commercial fishery. In addition, the Connecticut Department of Environmental Protection maintains and manages a northern pike spawning marsh within the project area, using the progeny produced at the marsh to augment northern pike stocks throughout the state.

The diadromous community includes 13 anadromous forms, as well as one catadromous (those that spawn in salt water and move to freshwater for development). This diadromous community, comprised of fishes that spawn in freshwater and use marine areas to mature, represents a majority of the diadromous stocks. In particular, the estuary supports one of the largest and most stable populations of American shad in the U.S., an anadromous form which, in turn, supports one of the oldest, most productive, and most renowned commercial and recreational fisheries in the region. Similarly, the population of the blueback herring, another anadromous form, is estimated to be the largest in the world. Other anadromous clupeids include the alewife, hickory shad, and gizzard shad (Dorosoma cepedianum); the last is in the process of naturally colonizing the river through range extension. These herring are more common in the mid-Atlantic riverine systems to the south; interestingly, the estuary also constitutes the southern extent of the range of Atlantic salmon and rainbow smelt (Osmerus mordax). The river's unique geographic location, productivity, and habitat variety allow it to support this correspondingly unique diversity of both southern and northern fishes.

Of particular note in the project area is the presence of shortnose sturgeon, a federally-listed endangered species. This species is known to use the project area waters for overwintering and feeding and, perhaps, to support juvenile development, although this has yet to be confirmed. White perch and sea lamprey are two other prominent anadromous fishes of the project area. While both are found in great abundance, white perch is prominent in the commercial and recreational fisheries. Although striped bass do not currently spawn in the Connecticut River, there is a very large run of the fish ascending the river for foraging on fishes, most notably blueback herring. This run of popular game fish has evolved into a nationally renowned sport fishery and multi-million dollar industry. The catadromous American eel spends the majority of its life in the river. It is abundant in all lifestages from elver to adult, and is a nocturnal scavenger; it, too, is fished commercially.

In summary, the Connecticut River estuary and tidal wetlands represent the most productive and diverse estuarine system for fisheries in New England. As a reflection of that productivity, the project area also supports the greatest fishing effort, recreationally and commercially, of any river system in New England. The river's location in the densely populated region of New England, halfway between New York City, New York, and Boston, Massachusetts, provides easy access for millions of anglers. This location, coupled with the river's high environmental quality, presents tremendous fishing and economic opportunities for the regional populace.

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