California and national wetland habitats shrink annually at an alarming rate. The 48 contiguous states have a dwindling 100 million acres of wetlands. The U.S. Fish & Wildlife Service estimates that up to 43% of the nation's 1,262 threatened and endangered species rely on wetlands for their survival.

Wetlands are unique biologic communities characterized by both aquatic and terrestrial features. Plants and animals that inhabit wetlands have successfully evolved morphological and physiological adaptations to the presence of high levels of salt and periodic inundation and desiccation, as well as to low concentrations of dissolved oxygen in the water- logged soils and exposure to alternating salt and fresh water. Many wetland inhabitants, including salt marsh plants and some water birds are able to excrete the excessive amounts of salt that are absorbed or ingested.

While the debate still rages (big bucks discussion) as to what constitutes a wetlands, a Supreme Court ruling in late August 2006 made a determination as to what a wetland is. Two groups of Michigan land owners asked the U.S. Supreme Court to strike down federal rules that protect almost half of the nation's streams and wetlands from pollution and bulldozer. Protections for wetlands miles away from waterways was extended in the Clean Water Act of 1972.

In California, wetlands are commonly classified according to the length of time that an area is inundated or saturated by water or the types of  plants and animals an area supports. Five major wetland classifications: marine, estuarine,  lacustrine, riverine, and palustrine. Marine and estuarine wetlands are associated with the ocean and include coastal wetlands, such as tidal  marshes. Lacustrine wetlands are associated with lakes, while riverine wetlands are found along rivers and streams. Palustrine wetlands may be  isolated or connected wet areas and include marshes, swamps, and bogs.

Most of California's coastal wetlands are estuarine salt marshes with associated tidal channels and mudflats.

Estuaries are formed where freshwater streams meet the sea, and contain variably brackish water. Salt marshes develop along the shores of protected estuarine bays and  river mouths, as well as in more marine-dominated bays and lagoons. Wetlands that are less common along the California coast are freshwater marshes, riparian wetlands, bogs, and vernal pools. Freshwater marshes, like salt water marshes, are vegetated mostly with herbaceous plants, predominantly cattails, sedges, and rushes.

Freshwater marshes have mineral soils  that are less fertile than those of salt marshes, and exhibit a greater variety of plant species than salt marshes. Riparian wetlands, which occur on the banks of steams, rivers, and lakes, commonly feature woody vegetation.

Studies of California wetlands and wetlands mitigation have provided some insights into efforts into creating wetlands of equal value to those lost to development.

Some Wetlands Birds in California

American peregrine falcon
American white pelican 
Bald eagle 
Belding's Savannah sparrow 
Black skimmer 
Black tern 
Burrowing owl 
California brown pelican 
California gnatcatcher
California gull 
California horned lark 
California least tern
Common loon 
Cooper's hawk 
Double-crested cormorant 
Elegant tern
Gull-billed tern 
Large-billed Savannah sparrow 
Least Bell's vireo 
Light-footed clapper rail  
Long-billed curlew 
Marsh hawk 
Merlin falcon 
Northern harrier 
Osprey 
Sharp-shinned hawk
Short-eared owl
Swainson's hawk 
Tri-colored blackbird 
Western least bittern
Western snowy plover
White-faced ibis