Seagrasses provide:
Productivity and Shelter
Seagrasses are a primarily food source for many organisms including the manatee (Trichechus
manatus) and green sea turtle (Chelonia mydas) both of which are endangered marine
herbivores. Many marine species also utilize seagrass habitats as feeding grounds and nursery
areas. Fishes including the tarpon (Megalops atlanticus), snook (Centropomus undecimalis),
ladyfish (Elops saurus), crevalle jack (Caranx hippos), and goliath grouper (Epinephelus itajara)
forage in seagrass habitats. Gray snapper (Lutjanus griseus), sheepshead (Archosargus
probatocephalus), spotted seatrout (Cynoscion nebulosus) and red drum (Sciaenops ocellota)
spend their juvenile stage in seagrass habitat, eventually moving on to mangroves as they
mature. Other commercially important species including spiny lobsters (Panulirus guttatus), pink
shrimp (Penaeus duorarum) and stone crabs (Menippe mercenaria) also use seagrasses as
nurseries.
Sediment Stabilization
Seagrasses stabilize bottom sediments with their dense roots and rhizomes that form a secure
mat. This sediment stabilization and erosion prevention is especially important during storms
and hurricanes that often threaten Florida’s coastline.
Water Clarity
Seagrasses are efficient at removing dissolved nutrients from waters that often enter coastal
waters as a result of runoff from the land. Seagrasses also trap fine sediments and particles from
both land and water. The settle out of the water column, becoming trapped among the blades and
roots of the seagrasses. The removal of sediments and nutrients from the water results in high
water clarity and nutrient-poor waters required for the survival of coral reefs.
FLORIDA KEYS: THREATENED AND ENDANGERED SPECIES
Threatened and Endangered Species include:
"Endangered" species are in danger of becoming extinct throughout all or the majority of its range
while a "threatened" species is one that is likely to become endangered in the near future. Each
species must be listed on the Federal list of endangered and threatened species before it can
receive protection under the Endangered Species Act. The ESA was enacted in 1973 to conserve
and set up recovery plans for listed species and associated habitats.
Numerous threatened and endangered species depend upon the habitats of the Florida Keys.
Schaus Swallowtail Butterfly
Currently ranging from Biscayne National Park to Key Largo and Lower Matecumbe Key, the
Schaus Swallowtail Butterfly is dwindling with populations numbering less than 1,000 individuals.
The primary reason for decline is loss of habitat, use of insecticides, collection of the larvae, and
extreme weather conditions. Recovery efforts for this endangered species includes captive
breeding programs to help restore the population.
Key Deer
Habitat use by the endangered key deer (Odocoileus virginianus clavium) includes pinelands,
hardwood hammocks, and mangrove swamps. Pinelands, hardwood hammocks and other
upland dry areas are utilized for feeding activities while mangrove swamps are used for shelter
from the heat during the day. Two-thirds of the key deer population inhabits Big Pine Key and No
Name Key. The remaining deer reside in the following keys: Lower Keys: Big Pine, Big Torch,
Cudjoe, Howe, Little Pine, Little Torch, Middle Torch, Sugarloaf, and Summerland. Keys located
further south lack a permanent supply of freshwater required by key deer for survival. The current
key deer population is estimated at around 300, up from the 1955 estimate of 25-80.
Lower Keys Marsh Rabbit
The lower keys marsh rabbit (Sylvilagus palustris hefneri) lives in coastal prairies and freshwater
marshes of the lower Keys. These habitats are rapidly disappearing due to development in the
lower keys, placing this endangered species under the threat of extinction.
Key Largo Woodrat and Key Largo Cotton Mouse
Tropical hardwood hammocks provide critical habitat for the Key Largo woodrat (Neotoma
floridana smalli) and the Key Largo cotton mouse (Peromyscus gossypinus allapaticola). Both
species originally ranged throughout Key Largo, however as a result of habitat destruction they
are currently limited to the northern third of the island and listed as endangered species. The
endangered Schaus swallowtail butterfly (Papilio aristodemus ponceanus) is also dependent
upon hardwood hammocks. This species is on the decline due to habitat destruction as well as
insecticide use and extreme weather conditions.
Sea Turtles
Marine and estuarine habitats surrounding the Keys provide habitat for threatened and
endangered species. The Florida population of green sea turtles (Chelonia mydas) has been
considered endangered since 1978. The declining population has been victim to commercial
harvesting for eggs and food as well as incidental by-catch in the shrimp fishery. Hawksbill sea
turtle (Eretmochelys imbricata), Atlantic Ridley sea turtle (Lepidochelys kempii), and leatherback
sea turtle (Dermochelys coriacea) are all listed as endangered species while the loggerhead sea
turtle (Caretta caretta) is considered threatened under the protection of the ESA. Recovery plans
have been established for all listed sea turtle species. The manatee (Trichechus manatus) is
another endangered aquatic animal observed from time to time in the waters surrounding the
Keys.
American Alligator
American alligator (Alligator mississippiensis) is protected due to its similarity in appearance to
the threatened American crocodile (Crocodylus acutus).In Florida, alligators are widespread and
are residents of Biscayne National Park in the Keys.
Other Threatened and Endangered Species
There are many other threatened and endangered species in the Florida Keys including the Stock
Island tree snail (Orthalicus rees), southern bald eagle (Haliaeetus leucocephalus), and roseate
tern (Sterna dougalli). For more information on threatened and endangered species, visit the
Florida Fish and Wildlife Commission's List of Florida's Endangered and Threatened Species
and Species of Special Concern.
- Productivity and Shelter
- Sediment Stabilization
- Water Clarity
Productivity and Shelter
Seagrasses are a primarily food source for many organisms including the manatee (Trichechus
manatus) and green sea turtle (Chelonia mydas) both of which are endangered marine
herbivores. Many marine species also utilize seagrass habitats as feeding grounds and nursery
areas. Fishes including the tarpon (Megalops atlanticus), snook (Centropomus undecimalis),
ladyfish (Elops saurus), crevalle jack (Caranx hippos), and goliath grouper (Epinephelus itajara)
forage in seagrass habitats. Gray snapper (Lutjanus griseus), sheepshead (Archosargus
probatocephalus), spotted seatrout (Cynoscion nebulosus) and red drum (Sciaenops ocellota)
spend their juvenile stage in seagrass habitat, eventually moving on to mangroves as they
mature. Other commercially important species including spiny lobsters (Panulirus guttatus), pink
shrimp (Penaeus duorarum) and stone crabs (Menippe mercenaria) also use seagrasses as
nurseries.
Sediment Stabilization
Seagrasses stabilize bottom sediments with their dense roots and rhizomes that form a secure
mat. This sediment stabilization and erosion prevention is especially important during storms
and hurricanes that often threaten Florida’s coastline.
Water Clarity
Seagrasses are efficient at removing dissolved nutrients from waters that often enter coastal
waters as a result of runoff from the land. Seagrasses also trap fine sediments and particles from
both land and water. The settle out of the water column, becoming trapped among the blades and
roots of the seagrasses. The removal of sediments and nutrients from the water results in high
water clarity and nutrient-poor waters required for the survival of coral reefs.
FLORIDA KEYS: THREATENED AND ENDANGERED SPECIES
Threatened and Endangered Species include:
- Schaus Swallowtail Butterfly
- Key Deer
- Lower Keys Marsh Rabbit
- Key Largo Cotton Mouse
- Key Largo Woodrat
- Sea Turtles
- American Alligator
"Endangered" species are in danger of becoming extinct throughout all or the majority of its range
while a "threatened" species is one that is likely to become endangered in the near future. Each
species must be listed on the Federal list of endangered and threatened species before it can
receive protection under the Endangered Species Act. The ESA was enacted in 1973 to conserve
and set up recovery plans for listed species and associated habitats.
Numerous threatened and endangered species depend upon the habitats of the Florida Keys.
Schaus Swallowtail Butterfly
Currently ranging from Biscayne National Park to Key Largo and Lower Matecumbe Key, the
Schaus Swallowtail Butterfly is dwindling with populations numbering less than 1,000 individuals.
The primary reason for decline is loss of habitat, use of insecticides, collection of the larvae, and
extreme weather conditions. Recovery efforts for this endangered species includes captive
breeding programs to help restore the population.
Key Deer
Habitat use by the endangered key deer (Odocoileus virginianus clavium) includes pinelands,
hardwood hammocks, and mangrove swamps. Pinelands, hardwood hammocks and other
upland dry areas are utilized for feeding activities while mangrove swamps are used for shelter
from the heat during the day. Two-thirds of the key deer population inhabits Big Pine Key and No
Name Key. The remaining deer reside in the following keys: Lower Keys: Big Pine, Big Torch,
Cudjoe, Howe, Little Pine, Little Torch, Middle Torch, Sugarloaf, and Summerland. Keys located
further south lack a permanent supply of freshwater required by key deer for survival. The current
key deer population is estimated at around 300, up from the 1955 estimate of 25-80.
Lower Keys Marsh Rabbit
The lower keys marsh rabbit (Sylvilagus palustris hefneri) lives in coastal prairies and freshwater
marshes of the lower Keys. These habitats are rapidly disappearing due to development in the
lower keys, placing this endangered species under the threat of extinction.
Key Largo Woodrat and Key Largo Cotton Mouse
Tropical hardwood hammocks provide critical habitat for the Key Largo woodrat (Neotoma
floridana smalli) and the Key Largo cotton mouse (Peromyscus gossypinus allapaticola). Both
species originally ranged throughout Key Largo, however as a result of habitat destruction they
are currently limited to the northern third of the island and listed as endangered species. The
endangered Schaus swallowtail butterfly (Papilio aristodemus ponceanus) is also dependent
upon hardwood hammocks. This species is on the decline due to habitat destruction as well as
insecticide use and extreme weather conditions.
Sea Turtles
Marine and estuarine habitats surrounding the Keys provide habitat for threatened and
endangered species. The Florida population of green sea turtles (Chelonia mydas) has been
considered endangered since 1978. The declining population has been victim to commercial
harvesting for eggs and food as well as incidental by-catch in the shrimp fishery. Hawksbill sea
turtle (Eretmochelys imbricata), Atlantic Ridley sea turtle (Lepidochelys kempii), and leatherback
sea turtle (Dermochelys coriacea) are all listed as endangered species while the loggerhead sea
turtle (Caretta caretta) is considered threatened under the protection of the ESA. Recovery plans
have been established for all listed sea turtle species. The manatee (Trichechus manatus) is
another endangered aquatic animal observed from time to time in the waters surrounding the
Keys.
American Alligator
American alligator (Alligator mississippiensis) is protected due to its similarity in appearance to
the threatened American crocodile (Crocodylus acutus).In Florida, alligators are widespread and
are residents of Biscayne National Park in the Keys.
Other Threatened and Endangered Species
There are many other threatened and endangered species in the Florida Keys including the Stock
Island tree snail (Orthalicus rees), southern bald eagle (Haliaeetus leucocephalus), and roseate
tern (Sterna dougalli). For more information on threatened and endangered species, visit the
Florida Fish and Wildlife Commission's List of Florida's Endangered and Threatened Species
and Species of Special Concern.
Importance of Seagrasses
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