How have people changed the marsh?

How have people changed the marsh?. Peabody Museum of Natural History, Yale University. , The Quinnipiac and Mill River salt marsh was once the largest salt marsh in the state. Gradually, the marshes have been filled in, leaving the 1000-acre Quinnipiac Marsh. Railroad bridges built across the marsh in the late 1800s decreased tidal action in the upstream marshes and reduced their salinity. Consequently, the dominant salt marsh grass species changed from salt hay (Spartina) to cattails (Typha). Now Phragmites, an Old World invader species, has encroached on much of the marsh. In the 1930s, ditches were dug to enhance drainage for mosquito control. Left untended the ditches became nurseries for fish, crabs and other invertebrates feeding on the abundant marsh microorganisms. Some of the small fish, such as Fundulus, now feed on mosquito larvae the ditches had once been meant to eradicate., How polluted is the Quinnipiac River? , The Quinnipiac was first declared polluted by the State Board of Health in 1914. In that era, 71 businesses and a number of municipalities dumped untreated wastewater directly into the river, but thanks to concerted state, federal and local action, all of Connecticut's rivers are much healthier than they were 50 years ago. Although such "point source" discharges have been largely brought under control, these controls can malfunction during periods of low water flow. Less readily discerned sources of pollution include embedded contaminants from past pollution, leachate from landfills (Shown in the map panel to your right) and the tire pond (above), and storm runoff from major highways, parking lots and lawns. Improved public access to the marsh can do much to improve quality of human life in the New Haven area; however, more intense human use also has the potential of placing the marsh's existing biodiversity at further risk., The muskrat and the osprey today , Muskrats are one of the most valuable fur animals in the US; in the 1960s and '70s 4,000 to 5,000 were trapped each year in the marsh. In the 1700s, the Quinnipiac and neighboring marshes contained primarily salt grasses and no muskrats lived there. As bridges restricted the tidal flow and the marshes filled in, the salt grasses were replaced by cattail, a favorite food of muskrats; the marsh came to support a large muskrat population. But between 1970 and 1990, a 78% decrease was reported in the number of muskrat lodges in the marsh, suggesting a comparable decline in population. This decline is thought to be linked to the Phragmites invasion, which supplanted the cattail muskrats thrive on. While mosquito-ditching has caused a decline elsewhere, it may not have been a factor here., To encourage nesting, osprey-platforms have been erected by the Quinnipiac River Watershed Association, other volunteer groups and the Connecticut Department of Environmental Protection. As a consequence, ospreys have indeed returned to the Quinnipiac Marsh. In 1996, one nest and one fledgling were sighted; in 2000, fourteen osprey fledged from six nests; by 2003, twenty-two osprey fledged from thirteen nests. Now, area residents can witness one of the world's great spectacles: an osprey snatching a shad, carp or flounder, and skimming over the marsh toward its nest with its prey in its talons., Learning more about the marsh , Although public access to the Quinnipiac Tidal Marsh is limited, it can be entered through the Fargeorge Preserve operated by the New Haven Land Trust. The NHLT is one of a number of governmental, nonprofit and volunteer organizations working towards preserving the marsh's biodiversity and improving public access. Other agencies involved in these efforts include the U.S. Environmental Protection Agency, The Connecticut Department of Environmental Protection, The New Haven Bird Club, The Office Of Long Island Sound, The Quinnipiac River Watershed Association, The Quinnipiac River Watershed Partnership, and Trout Unlimited., This Peabody Museum of Natural History exhibit was made possible by a grant from the Geoffrey Hughes Foundation to the Quinnipiac River Watershed Partnership, Tidal Marsh Work Group.