Lignumvitae Key Aquatic Preserve

Lignumvitae Key Aquatic Preserve holds significant archaeological value, with documented historical structures and archaeological sites both within and adjacent to its boundaries. Although no archaeological resources are officially listed within the aquatic preserve itself, nearby sites offer glimpses into the region's rich history, including:

• Prehistoric shell middens and burial mounds on Lignumvitae Key provide evidence of Native American presence.
• The Matheson House on Lignumvitae Key, a caretaker's home built in 1919, serves as the visitor center for the Lignumvitae Key Botanical State Park. It showcases how early island inhabitants relied on the surrounding land and sea for their livelihood.
• The San Pedro wreck, submerged south of Indian Key, dates back to 1733 and represents a significant part of Florida's maritime history. It became the San Pedro Underwater Archaeological Site in 1989.
• Indian Key, although south of the preserve's boundary, has been inhabited by various cultures since prehistoric times and served as a prominent trading village in the 1800s.

The Lignumvitae Key Aquatic Preserve is part of the Florida Keys, an archipelago formed from ancient coral reefs. The formation process began around 125,000-100,000 years ago during a period of rising sea levels, creating conditions favorable for coral growth. Over time, these submerged reefs cemented into rock, forming the Key Largo Limestone that characterizes Lignumvitae Key and other islands in the Upper and Middle Keys.

• Lignumvitae Key itself is a prime example of an ancient domed patch reef, with elevations reaching 16 feet above sea level at its center.
• Key Largo Limestone is a porous rock primarily composed of fossilized coralline algae and coral skeletons.
• This limestone consists of three main rock types: calcarenite (formed from mollusks, algae and other fragments), coralline limestone (dominated by large, intact coral heads) and calcilutite (comprised of fine, well-cemented sediments).

The unique geological history of the Florida Keys has created a diverse range of habitats within the Lignumvitae Key Aquatic Preserve, supporting a rich variety of marine life.

Lignumvitae Key Aquatic Preserve features a diverse ecosystem encompassing a transitional zone between Florida Bay and the Atlantic Ocean. This unique location supports a variety of habitats, including seagrass flats, mangroves and hardbottom communities, which provide shelter, food and breeding grounds for a wide array of marine life. Seagrass beds serve as nurseries for commercially and recreationally important fish and crustaceans, while mangrove swamps offer protection for shorelines and habitat for birds and other wildlife. Hardbottom communities provide a substrate for corals, sponges and algae, further enhancing biodiversity within the preserve. The interaction of these habitats creates a complex and productive ecosystem that is vital to the health of the Florida Keys.

Wildlife Habitat and Ecosystem Type
Lignumvitae Key Aquatic Preserve is recognized as an outstanding water resource of the state. The three navigable channels that traverse the preserve from north to south are a transitional zone between Florida Bay and the Atlantic Ocean.

Invertebrates
Crustaceans: Spiny lobster, Stone crab

Nesting and Migrating Birds
Great White Heron, Bald Eagle, Roseate spoonbill, Great Blue heron, Brown pelican, peregrine falcon, osprey, White ibis, Great egret, ducks, grebes, loons, cormorants

Mammals
Atlantic bottlenose dolphin, West Indian manatee, raccoon, marsh rabbit, opossum

Reptiles
American crocodile, Atlantic green sea turtle, Atlantic loggerhead sea turtle, Atlantic hawksbill sea turtle

Fish
Bonefish, tarpon, permit, barracuda, jack, red grouper, gray snapper, yellowtail snapper, mutton snapper, common snook, smalltooth sawfish

Other Species 
Plants: lignum vitae tree, milkbark, Florida boxwood

A full list of species can be found in the management plan.

Year-round. From December to April, known as the dry season, the region gets nearly 25% of its annual rainfall, typically before the arrival of cold fronts. The wet season spans from June to October, accounting for about 65% of the total annual precipitation, primarily through showers and thunderstorms. May and November are generally regarded as transitional months between the two seasons. During the wet season, easterly waves can sometimes bring heavy rain, and rare hurricanes may also result in substantial rainfall. 

No guided tours or formal education programs are available within the aquatic preserve. Interpretive signs detailing the ecology, recreational opportunities and regulations within Lignumvitae Key Aquatic Preserve are installed at popular access points, including marinas, kayak/boat launches and the recreation area on the Fills.

Lignumvitae Key Botanical State Park offers guided tours of the island, including visits to the historic Matheson House.

Yes. Aquatic preserves often are adjacent to other conservation areas that may have nesting birds or other easily disturbed wildlife. Please do not let your pet run free in areas not designated for pets, and please pick up after your pet to avoid hazardous pathogens in our coastal waters. However, visitors should check with state parks for rules specific to Lignumvitae Key and Indian Key. Crocodiles, while shy, are often sighted in the aquatic preserve and can be a hazard to small animals.

Follow current FWC saltwater fishing regulations.

Most areas outside of marked channels are designated No Internal Combustion Motor Zones to protect the shallow seagrass beds and avoid disturbing nesting birds.

Seagrass is protected within aquatic preserves; avoid shallow waters and raise motor if over seagrass. Damage to seagrass can result in a fine up to $1,000.

Call Florida Fish and Wildlife Conservation Commission at 1-888-404-FWCC (3922).

Report any unusual sightings, including marine debris; vessel groundings and anchor damage; invasive species; harmful algal blooms; fish disease and fish kills; discolored water; and coral disease and bleaching to SEAFAN.

ADA accommodations are specific to each access point and the managing entity for that site. 

There are no fees required by the preserve, but both Lignumvitae Key Botanical State Park and Indian Key Historic State Park have entrances fees at self-service stations on the islands. 

The staff of the Aquatic Preserve organize both land- and kayak-based clean-ups, as well as collaborate in partner-led cleanup events throughout the year. These efforts are often promoted through the Friends of the Islamorada Area State Parks, a nonprofit organization dedicated to protecting the waters of Lignumvitae Key Botanical State Park and the surrounding aquatic preserve. For more details, please contact the Aquatic Preserve Manager.