Editing Biscayne National Park (section)

===Shoreline and mangrove swamp===
[[File:Biscayne American Crocodile NPS1.jpg|thumb|alt=A smiling American crocodile|American crocodile]]
The mainland shorelines are dominated by a marshy transitional zone chiefly populated by [[Rhizophora mangle|red mangrove]] and [[Avicennia germinans|black mangrove]] growing from the shallow water, with [[Laguncularia racemosa|white mangrove]] growing farther back from the water's edge. The trees' aerial root structure provides a sheltered habitat for crabs, fish and wading birds. The brown waters within the mangrove thickets are nurseries for fish, mollusc and crustacean larvae that require a quiet sheltered environment before the immature animals can disperse into open waters.<ref name=npsbisc111>{{cite web|title=Mangroves|url=http://www.nps.gov/bisc/naturescience/mangroves.htm|work=Biscayne National Park|publisher=National Park Service|access-date=19 November 2012}}</ref> Mangroves shed leaves at about {{convert|2|to|4|ST/acre}} per year, providing food for fish, worms and crustaceans. Because the carbon in the leaves is sequestered by incorporation into animals, the mangrove swamp is estimated to have two to three times the ability to [[Carbon sequestration|sequester carbon]] of terrestrial forests.<ref name=npsbisc43>{{cite web|title=Mangroves and Climate Change|url=http://www.nps.gov/bisc/naturescience/mangroves-and-climate-change.htm|work=Biscayne National Park|publisher=National Park Service|access-date=26 November 2012}}</ref> The mangrove forest on Biscayne Bay is the longest on Florida's east coast. Shoreline and island mangrove swamps, together with the bay, represent a significant nursery for the marine life of southeast Florida.<ref name=sotpbisc1>NPCA, p. 1</ref>

The salt-tolerant mangrove margin has expanded inland as freshwater flow into the bay has been [[river engineering#Channelization|channelized]], replacing freshwater [[Cladium|sawgrass]] marshes. The L-31E coastal storm surge [[levee]] inland of the park's western boundary has played a significant role in isolating former freshwater marshlands from their water sources. At the same time, tidal water does not reach the interior of the coastal margin, limiting interchange between salt and freshwater ecosystems.<ref name=npca16>NPCA, p. 16</ref>

Bird life on the shoreline includes [[yellow-crowned night heron]]s, [[loggerhead shrike]]s, prairie warblers and shorebirds. [[Mangrove cuckoo]]s, a notoriously difficult-to-observe species, may be seen at Convoy Point and Black Point. Biscayne has one of the largest populations of mangrove cuckoos in Florida.<ref name=npsbisc28/>

The park's margins are habitat for the threatened [[American crocodile]]. The construction of miles of cooling water canals in the [[marl]] lands close to the shore behind the Turkey Point power plant, and the canals' warm waters, have provided a nearly ideal environment for crocodile nesting, making the power plant a nursery for many of those living in the park.<ref name=bragg1>{{cite news|last=Bragg|first=Rick|title=In South Florida Canals, Revival of Rare Crocodiles|newspaper=The New York Times|date=June 29, 1999}}</ref><ref>{{cite web|url=http://www.fpl.com/environment/plant/pdf/turkey_point_crocodile_fact_sheet.pdf|title=Providing a home for the American crocodile|publisher=Florida Power & Light|url-status=dead|archive-url=https://web.archive.org/web/20121124001057/http://www.fpl.com/environment/plant/pdf/turkey_point_crocodile_fact_sheet.pdf|archive-date=2012-11-24}}</ref><ref name=crocdocs1>{{cite web|title=Status, Distribution, and Habitat Relations of the American Crocodile in Florida (Abstract)|url=http://crocdoc.ifas.ufl.edu/projects/americancrocodile/|work=The Croc Docs|publisher=University of Florida|access-date=22 November 2012}}</ref> Although crocodiles and [[American alligator]]s both occur in extreme southern Florida, alligators are uncommon in Biscayne,<ref name=npsbisc22>{{cite web|title=Threatened and Endangered Animals in Biscayne National Park|url=http://www.nps.gov/bisc/naturescience/threatened-and-endangered-animals.htm|work=Biscayne National Park|publisher=National Park Service|access-date=22 November 2012}}</ref> since alligators mainly inhabit fresh waters found farther inland, while crocodiles can live in Biscayne's somewhat saltier estuarine waters.<ref name=mazzotti1>{{cite web|last=Mazzotti|first=Frank J.|title=Status and Conservation of the American Crocodile in Florida: Recovering an Endangered Species While Restoring an Endangered Ecosystem|url=http://crocdoc.ifas.ufl.edu/publications/reports/american_croc2003.pdf|publisher=University of Florida, Ft. Lauderdale Research and Education Center|access-date=22 November 2012|author2=Cherkiss, Michael S.|page=iii|year=2003}}</ref>