STATUS AND TRENDS IN MANGROVE AREA EXTENT WORLDWIDE

United States

Vegetation description

In the United States of America, mangroves are largely concentrated in the southern parts of Florida and form a major vegetation type in the southern three of that state. The greatest structural development is in the South West region, because of the high concentration of nutrients and the moderating coastal salinity regimes. The species include: Acrostichum aureum, Avicennia germinans, Conocarpus erectus, Laguncularia racemosa, Rhizophora mangle, and an associated species Tabebuia palustris. Large areas of mangroves fall within the complex of protected areas which make up much of the land and the sea area of southern Florida, and there are a total of 48 protected areas with mangrove.

Spalding, M.D., Blasco, F. & Field, C.D., eds. 1997 World Mangrove Atlas. The International Society for Mangrove Ecosystems, Okinawa, Japan. 178 pp.

National level mangrove area estimates

Year

Area
(ha)

Source

Trend

Methodology/Comments

1983

205 000

Hamilton, L.S. and Snedaker, S.C., eds. Handbook for Mangrove Area Management. IUCN, Gland, Switzerland. UNESCO Paris & East-West Center, Hawaii; 123 pp

Secondary reference, no primary source provided. The "Year" is the publication year.

1991

255 100

Johnston, J.B., Watzin, M. C., Barras, J.A., Handley, L.R. 1995. Gulf of Mexico Coastal Wetlands: Case Studies of Loss Trends. In: Our living resources. A report to the Nation on the distribution, abundance and health of US plants, animals and ecosystems. US Department of the interior National Biological Center. Washington DC. http://biology.usgs.gov/s+t/noframe/m4143.htm

X

Remote sensing. The document provides the breakdown by state: Alabama, Florida, Mississipi, Louisiana, and Texas.

1991

280 744

Snedaker, S.C. 1991. Personal communication.

Cited in: Fisher, P and Spalding, M.D. 1993. Protected areas with mangrove habitat. Draft Report World Conservation Centre, Cambridge, UK. 60 pp. It provides the breakdown by states (Alabama, California, Florida, Louisiana, Mississipi and Texas).

2001

197 648

Ibid.

X

Combined national level mangrove estimate based on the following sources: Alabama, Lousiana, Mississippi, Texas: Johnston, J.B., Watzin, M. C., Barras, J.A., Handley, L.R. 1995. (see above). California: Snedaker, 1991 in Fisher, P and Spalding, M.D. 1993. (see above). Hawaii: Allen, J. A. 1998. Mangrove as alien species: the case of Hawaii. Global Ecology and Biogeography Letters 7:61-71. Florida: Department of Environmental Protection Florida Marine Research Institute. 2002. Florida's Mangroves “Walking trees”. Pamphlet by the Department of Environmental Protection Florida Marine Research Institute, St. Petersburg, FL. The reference year is the area weighted average.

Trends in mangrove area extent over time

The estimate for 1980 has been obtained applying FRA 1990 (FAO,1995) annual forest cover change rate 1980-1990 (-0.1 percent) to the 1991 figure.

Year	Area (ha)	Source	Trend	Methodology/Comments
1983	205 000	Hamilton, L.S. and Snedaker, S.C., eds. Handbook for Mangrove Area Management. IUCN, Gland, Switzerland. UNESCO Paris & East-West Center, Hawaii; 123 pp		Secondary reference, no primary source provided. The "Year" is the publication year.
1991	255 100	Johnston, J.B., Watzin, M. C., Barras, J.A., Handley, L.R. 1995. Gulf of Mexico Coastal Wetlands: Case Studies of Loss Trends. In: Our living resources. A report to the Nation on the distribution, abundance and health of US plants, animals and ecosystems. US Department of the interior National Biological Center. Washington DC. http://biology.usgs.gov/s+t/noframe/m4143.htm	X	Remote sensing. The document provides the breakdown by state: Alabama, Florida, Mississipi, Louisiana, and Texas.
1991	280 744	Snedaker, S.C. 1991. Personal communication.		Cited in: Fisher, P and Spalding, M.D. 1993. Protected areas with mangrove habitat. Draft Report World Conservation Centre, Cambridge, UK. 60 pp. It provides the breakdown by states (Alabama, California, Florida, Louisiana, Mississipi and Texas).
2001	197 648	Ibid.	X	Combined national level mangrove estimate based on the following sources: Alabama, Lousiana, Mississippi, Texas: Johnston, J.B., Watzin, M. C., Barras, J.A., Handley, L.R. 1995. (see above). California: Snedaker, 1991 in Fisher, P and Spalding, M.D. 1993. (see above). Hawaii: Allen, J. A. 1998. Mangrove as alien species: the case of Hawaii. Global Ecology and Biogeography Letters 7:61-71. Florida: Department of Environmental Protection Florida Marine Research Institute. 2002. Florida's Mangroves “Walking trees”. Pamphlet by the Department of Environmental Protection Florida Marine Research Institute, St. Petersburg, FL. The reference year is the area weighted average.