Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

Habitat Modification
Much of the region’s estuarine wetlands have been heavily modified, primarily from
agricultural land conversion and urban development (NRC 1996). Although most
estuarine wetland losses result from conversions to agricultural land by ditching,
draining, or diking, these wetlands also experience increasing effects from industrial and
urban causes. By 1980, an estimated 27,180 acres of intertidal or shore wetlands had
been lost at 11 deltas in Puget Sound (Bortleson, Chrzastowski et al. 1980). Tidal
wetlands in Puget Sound amount to roughly 18% of their historical extent (Collins and
Sheikh 2005). Coastal marshes close to seaports and population centers have been
especially vulnerable to conversion with losses of 50-90%. By 1980, an estimated 27,180
acres of intertidal or shore wetlands had been lost at eleven deltas in Puget Sound
(Bortleson, Chrzastowski et al. 1980). More recently, tidal wetlands in Puget Sound
amount to about 17-19% of their historical extent (Collins and Sheikh 2005). Coastal
marshes close to seaports and population centers have been especially vulnerable to
conversion with losses of 50-90% common for individual estuaries. Salmon use
freshwater and estuarine wetlands for physiological transition to and from saltwater and
rearing habitat. The land conversions and losses of Pacific Northwest wetlands constitute
a major impact. Salmon use marine nearshore areas for rearing and migration, with
juveniles using shallow shoreline habitats (Brennan, Higgins et al. 2004).
About 800 miles of Puget Sound’s shorelines are hardened or dredged (PSAT 2004;
Ruckelshaus and McClure 2007). The area most intensely modified is the urban corridor
(eastern shores of Puget Sound from Mukilteo to Tacoma). Here, nearly 80% of the
shoreline has been altered, mostly from shoreline armoring associated with the
Burlington Northern Railroad tracks (Ruckelshaus and McClure 2007). Levee
development within the rivers and their deltas has isolated significant portions of former
floodplain habitat that was historically used by salmon and trout during rising flood
waters.
Urbanization has caused direct loss of riparian vegetation and soils and significantly
altered hydrologic and erosion rates. Watershed development and associated
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