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Ecology of Florida > Migration Patterns

Migratory Birds
Many birds spend summer in New England or farther North on the East coast of the U.S. and migrate through Florida on their way to South America or the Caribbean. Water birds that winter in Cuba, Hispaniola, and Puerto Rico use Florida as their last land stop before the islands, while most land birds will fly from Florida to the coast of Mexico in order to continue moving to South America while remaining over land. Ospreys (Pandion haliaetus) that spend summers in the Eastern half of the U.S. use multiple routes through Florida to reach the Yucatan peninsula, the Caribbean islands, and South America. Upon their return, birds crossing the Gulf of Mexico need to stop in Florida to feed and replenish their energy after the strenuous flight over water. Some species like the Red Knot (Calidris canutus rufa) stay in Florida for the winter. In the case of the Red Knot, the east coast of the state is used as a stopover on the way to the Caribbean and as a over-wintering area. Some birds returning North in the fall have migration patterns that bring them into the path of Gulf hurricanes, increasing the danger of the flight as well as the need for abundant resources on the North coast of the Gulf.

Migrating birds arrive in highest densities in areas with dense hardwood forests. For those in need of food, this habitat could indicate to them an abundance of resources, and many stop over in the panhandle of Florida in hardwood and pine forests close to the coast. Conservation of these forests will be important for the future of many migrating bird species; with so many birds using these forests to forage after strenuous flights, degradation or loss of this habitat could lead to high mortality as the birds quickly use up a smaller pool of resources. The same can be said for the East coast of the state, where habitat loss caused by sea level rise, beach erosion, and development threaten migratory routes with habitat loss. Although the Migratory Bird Treaty Act made the "taking, killing, or possessing migratory birds unlawful," habitat must also be protected to help birds that migrate through Florida survive.

TIDAL CREEK ARTICLE

A tidal creek, tidal channel, or estuary is the portion of a stream that is affected by ebb and flow of ocean tides, in the case that the subject stream discharges to an ocean, sea or strait. Thus this portion of the stream has variable salinity and electrical conductivity over the tidal cycle, [and flushes salts from inland soils. Tidal creeks are characterized by slow water velocity resulting in buildup of fine, organic sediment in wetlands. ]Creeks may often dry to a muddy channel with little or no flow at low tide, but with significant depth of water at high tide.

Due to the temporal variability of water quality parameters within the tidally influenced zone, there are unique biota associated with tidal creeks which are often specialised to such zones. [Nutrients and organic matter are delivered downstream to habitats normally lacking these, while the creeks also provide access to inland habitat for salt-water organisms. ]

Development
Whereas areas of coastline that experience high wave activity are usually characterized by beaches, areas sheltered from wave action may develop tidal wetland systems. In these areas, creeks form to drain the high part of the coast. They are often very sinuous, and form by headwater retreat and downward incision of the water as it flows from inland to the shore. Tidal creeks deposit sediment in a process called accretion, which can maintain a flat plain by counteracting sea level rise or land subsidence. High tidal flow will maintain channels, while slower flow velocity can lead to closure of tidal creeks as they become clogged with sediment. Well-developed wetlands have sharp-banked tidal creeks, with vegetation stabilizing the sides of the creeks. Such tidal creeks will also be connected in networks: a multitude of smaller creeks called first-order creeks will feed into large ones, creating complex patterns of drainage.

Human Impact
Especially in areas prone to compaction or subsidence - like peat wetlands - human use of tidal creek flow can lead to the expansion of the creeks. Natural subsidence is compounded by anthropogenic sediment compaction, lowering the land level. Deforestation and other human-development-related processes can destabilize the banks of creeks and increase the amount of sediment in them. This slows the velocity of the water, which means that instead of cutting deeper channels the water flows gently farther inland in shallow channels. Human development in tidal areas often results in diking, which changes the course of the tidal creeks and the salinity of the tidal area into freshwater.

Restoration of tidal wetlands begins with restoration of the creek systems, which determine the shape of the land, the nutrient and salinity levels, and the type of vegetation and animal communities in a wetland.