All three of these species utilize a remarkable method of propagation. Seeds sprout while still on
the trees and drop into the soft bottom around the base of the trees or are transported by currents
and tides to other suitable locations.
Florida's mangroves are tropical species; therefore, they are sensitive to extreme temperature
fluctuations as well as subfreezing temperatures. Research indicates that salinity, water temperature,
tidal fluctuations, and soil also affect their growth and distribution. Mangroves are common as far
north as Cedar Key on the Gulf coast and Cape Canaveral on the Atlantic coast. Black mangroves can
occur farther north in Florida than the other two species. Frequently, all three species grow
People living along the south Florida coasts benefit many ways from mangroves. Mangrove forests
protect uplands from storm winds, waves, and floods. The amount of protection afforded by mangroves
depends upon the width of the forest. A very narrow fringe of mangroves offers limited protection,
while a wide fringe can considerably reduce wave and flood damage to landward areas by enabling
overflowing water to be absorbed into the expanse of forest. Mangroves can help prevent erosion by
stabilizing shorelines with their specialized root systems. Mangroves also filter water and maintain
water quality and clarity.
Mangrove Losses In Florida
It is true that mangroves can be naturally damaged and destroyed, but there is no doubt that human
impact has been most severe. Florida Marine Research Institute scientists are studying changes in
Florida's coastal habitats. The scientists are able to evaluate habitat changes by analyzing aerial
photographs from the 1940's and 1950's and satellite imagery and aerial photography from the 1980's.
Frequently the changes illustrate loss of mangrove acreage. Through researching the history of study
sites, these losses are often attributed to human activities.
Tampa Bay, located on the southwest Florida coast, has experienced considerable change. it is one of
the ten largest ports in the nation. Over the past 100 years, Tampa Bay has lost over 44 percent of
its coastal wetlands acreage; this includes both mangroves and salt marshes.
The next major bay system south of Tampa Bay is Charlotte Harbor. Unlike Tampa Bay, Charlotte Harbor
is one of the least urbanized estuarine areas in Florida. However, there has been some mangrove
destruction here also. Punta Gorda waterfront development accounts for 59 percent of the total loss.
An increase in mangrove acreage was noted in parts of the Harbor. This is due to changes in the system.
As tidal flats were colonized by mangroves, tidal flat acreage decreased and mangrove acreage increased.
Spoil islands, created as by-products of dredging, also provide suitable habitat for mangroves.
A changing system was also observed on the Southeast Florida coast in Lake Worth, near West Palm Beach.
Lake Worth naturally evolved from a saltwater lagoon to a freshwater lake. Human changes modified the
lake back to an estuarine lagoon. Lake Worth has experienced an 87 percent decrease of its mangrove
acreage over the past forty years. Mangroves appear to be replaced by Australian pines and urbanization.
The remaining 276 acres of mangroves occur in very small scattered areas and are now protected by
Another study site included the Indian River from St. Lucie Inlet north to Satellite Beach. Indian
River is the longest saltwater lagoon in Florida. There are just less than 8,000 acres of mangroves within
the study site, but only 1,900 acres are available as fisheries habitat because of mosquito impoundments.
Consequently, 76 percent of the existing mangrove areas are not productive to fisheries. A total of 86
percent of the mangrove areas have been lost to fisheries since the 1940's.
State and local regulations have been enacted to protect Florida's mangrove forests. Local laws vary. Be
sure to check with officials in your area prior to taking any action to determine if a permit is required.
Further information on state regulations is available at
Mangroves are one of Florida's true natives and are part of our state heritage. It is up to us to ensure a
place in Florida's future of one of our most valuable coastal resources - mangroves.
This page was derived from a brochure developed by the Department of Environmental Protection, Florida
Marine Research Institute with funds provided by a grant from the U.S. Office of Ocean and Coastal
Resource Management, NOAA.
Artwork courtesy of the U.S. Fish and Wildlife Service