By Nancy Richie
Most people know by now that the protected, threatened, Loggerhead sea turtles will be nesting on Florida beaches during the spring months, with hatchlings emerging in late summer. Sea turtles symbolize the health of the oceans and are very charismatic for residents and tourists alike who embrace them with interest and protection. But, there is another turtle that has the same federal and state protection status, threatened, that nests this time of year that populates Marco Island in relatively high numbers which, unlike the Loggerhead Sea Turtles, does not go in the water, but resides in the upland, sandy habitats of the Island. It is the Gopher Tortoise, Gopherus polyphemus.
The genus name, Gopherus means “burrower” and the species name, polyphemus means “many voiced”. It is the only land turtle, or tortoise species remaining in the southeastern United States.
Noted by the famous American naturalist, William Bartram in 1773, upon his arrival in South Carolina while heading south to survey flora and fauna, he observed gopher tortoises in the “high dry hills” and pasture lands south of the Savannah River. In his writings he clearly described “dens or caverns dug in sand-hills by the great land-tortoise, called here Gopher”. Many historians, residents and visitors of Florida have known about this tortoise, its burrows and behavior, as they have likely seen it along road sides, pastures, and fields. And as development of Florida increases, they are seen commonly in places that humans frequent.
Distribution of this species is dependent on climate but also greatly influenced by the human impacts. These tortoises prefer high and dry, sandy soils with forage materials ranging from grasses, leaves, legumes, cacti and vines. A reptile, dependent on the sun to warm them and incubate their eggs, they thrive in sustained moderate to warm temperatures thus keeping their range throughout Florida and no further north than southern areas of Mississippi, Alabama and Georgia. (The sparse populations of gopher tortoises in South Carolina were relocated.) There are many isolated Floridian populations, most likely due to human distribution and development practices in such places as Sanibel, Egmont Key, Cape Sable and Marco Island.
The gopher tortoise is easy to identify with its large, elephant-like hind legs and spade-like front legs. The front legs are covered in scales and end in five strong, nails (claws) which are used for digging burrows that can be up to 40 feet in length. The sturdy hind legs are used for balance and pushing during digging and fighting. The top shell, the carapace, is typically brown in color, smooth and rounded, without ridges or spurs, and flares out over the legs and head. The carapace is covered in thick scutes that have circular rings (annuli) like a tree stump, but do get worn off by moving in the coarse, sandy soils. The bottom bone, plastron, is made of nine to eleven bones. There is a short, fat tail that curves downward. Unlike a sea turtle, the tortoise head, legs and tail can all be tucked within the shell for protection. Growing in length from a one and half inch hatchling to approximately 13-15 inches in adulthood and approximately 9 to 10 pounds; a gopher tortoise can live for approximately 60 years.
Very similar in looks, one can only tell a male and female tortoise apart by looking at the plastron. The male’s plastron will be indented, or concave, giving it the ability to mount the female during mating. Females are generally smaller in size also. Courting between the sexes occurs in early spring, with eggs laid in April through June. An average of nine eggs will be deposited in the sand near the mouth of the burrow opening, allowing the warm sun to incubate for 80 to 100 days. Eggs and hatchlings have a high predation rate – snakes, raccoons, birds, hawks prey upon the eggs and hatchlings easily, so survival rate is very low.
As herbivores and foraging animals, diversity of vegetation species is important for the tortoises’ healthy diet requiring different plants at different stages of life. Eating large variety of plants, such as grasses, leaves and legumes; the juveniles tend to eat more legumes for protein components for growth whereas the adults eat more fibrous plant material. Clearing natural vegetation, specifically groundcovers, grasses, midstory plants and vines, does great harm to the tortoises’ health and could drive them to abandon their burrows in a quest to find more nutrition and cover from predators. Basically, the tortoises don’t live on grass alone.
This tortoise is known as a “key stone” species in Florida due to the fact that their burrows can provide shelter for up to 360 species protecting them from predators, weather and fire events. Examples of the wide range of occupants in a burrow include many insects, reptiles (Black Racer, Rat Snake), amphibians (Gopher Frog, Southern Toad, Greenhouse Frog), mammals (Florida Mouse) and birds (in the burrow – Burrowing Owls and feeding at the burrow – Warblers, Vireos, Redstarts).There are two locations on Marco Island where burrowing owls and tortoises have shared a burrow. The burrow consists of the burrow “apron”, a mound of sand that has been excavated during the digging of the burrow, a burrow “mouth”; a half-moon shape that typically is as wide as the occupying tortoises length; the burrow “tunnel”, that can be up to 40 feet in length and can be at a ten foot depth or more (depending on water table levels in the area); ending in the “chamber.” There is one way in and one way out. A tortoise can have multiple burrows with males having more than females on average.
It is estimated that the Florida Gopher Tortoise population has decreased by 30% over the past few years. Marco Island’s population is being surveyed by a graduate student from Florida Gulf Coast University, Julie Ross. She is in her sixth year of studying the Island’s tortoises for their genetics and overall population statistics and has gathered information on over 200 tortoises. She estimates that there may be 300-400 tortoises on the Island. Being an isolated Florida population, this island population is further sub-isolated with large concentrations of tortoises found in the Estates and Sheffield/Dogwood Drive areas, smaller numbers on Spinnaker Drive and west side of Hideaway Beach, on Horr’s Island, and small areas that were previously disturbed such as the Steven’s Landing property. Ms. Ross plans to study the impacts on these isolated populations and examine ideas that can help sustain the current population as development continues.
The gopher tortoise is listed by the federal government and the State of Florida as Threatened. Without proper management this tortoise is likely to become listed and protected as an endangered species in the near future. The primary reason for the decline of this species is habitat destruction. Due to the gopher tortoises’ protected status, it is illegal to take, harm, or harass this species under the Endangered Species Rule, Chapter 39 of the Florida Administrative Code. Additionally, the destruction of gopher tortoise burrows and their habitat constitutes “taking” under this law except when authorized by specific permit. If you are planning the development of a current gopher tortoise habitat or have been notified that tortoises are located on your property, you should be fully aware of your responsibilities and the available management options.
It is important to note that knowing where to look or not for the presence of tortoises can avoid decisions that kill tortoises. Though control burns in long leaf pine forests and roller chopping in saw palmetto habitat are considered management practices for concentrated tortoise populations, it is known now that tangled patches of vegetation, such as Greenbriar (Smilax) patches, fallen limbs and similar vegetation such as Bracken Fern or Wild Grape vines are places that juveniles, subadults and hatchlings are found taking shelter and feeding upon. Often “abandoned” burrows are their shelters and the mats of vines have been found to be brooding areas where hatchlings hide and forage. With the rapid decline of this species, studies have increased knowledge of habitat and population needs prompting consultants and land managers alike reporting to experts and regulators that they have killed many tortoises due to their ignorance on habitat needs.
The following list provided by the Florida Fish & Wildlife Conservation Commission (FWC) offers options to develop your property and assist in conserving this species in decline:
• Avoid developing in the area occupied by tortoises. No permit is required.
• Develop so as to avoid gopher tortoise burrows by avoiding concentrations of burrows altogether and/or staying at least 25 feet radius from entrances of individual burrows. No permit is required but the FWC management guidelines are followed.
• Relocate, through permitting options, of on site or off site relocation, those tortoises that would be within the footprint or within 25 feet of development/construction activities. An environmental consultant who has been certified as a Gopher Tortoise Agent must be used to further explore this option. A permit is required from the FWC. For further information on permitting, population and habitat management and the State’s Gopher Tortoise Management Plan, please go to www.MyFWC.com.
What Can You Do?
Slow Down: Gopher Tortoises frequently cross our island roads so use caution and follow the speed limits. Inlet Drive, Ludlow Court, Spinnaker Drive, and State Road 92 are a few roads that have frequent tortoise mortalities due to speeding vehicles. Please be observant and slow down.
Keep it Healthy: If you have tortoises and other wildlife in your neighborhood, use less herbicide and pesticides on your landscape. More than likely they will graze and forage in your yard.
Go Native: Plant native species to conserve water and money but also provide forage areas for the tortoises. As well as providing habitat for native animal species, many native species of plants can add flowers, fruits and interest to your landscape.
Get Help: If you observe destruction or harassment of a tortoise, its burrow or habitat, please call FWC at 1-888-404-3922 (FWCC), a 24 hour, 365 day animal alert hotline. If you come across an injured or distressed tortoise, please call the Conservancy of SW Florida’s Wildlife Rehab Clinic at 239-262-2273.
Enjoy!: Watch at a respectful distance and enjoy the free-ranging population of gopher tortoises of Marco Island!
If you need additional information or have any questions and/or comments, please contact the City of Marco Island at 239-389-5003 (office), 239-825-0579 (mobile) or [email protected] Nancy Richie is a long time Island resident and Marine Biologist.