A Field Day with Gopher Tortoises

Defenders helps count gopher tortoise burrows

Defenders works to save wildlife every day, and we recently spent one of those days in a special and different way – the Florida staff ventured into the field to survey for gopher tortoises and their burrows at Boyd Hill Nature Preserve here in St. Petersburg.

It was slow going for us humans – searching for tortoise burrows while making our way through stands of dense saw palmetto, staying wary of ankle-grabbing logs and veering clear of prickly pear cactus wasn’t easy. But the gopher tortoise is finely adapted to this ancient scrub and sandhill habitat, as well as to other Florida natural communities. It was the subject of my master’s degree and a focal species in the consulting work I did before coming to Defenders, so it was great fun to see my colleagues now taking part for the first time in the burrow surveying, identification and data collection.

The gopher tortoise lives in dry, sandy uplands, such as pine flatwoods, scrub, oak-sandhills and coastal dunes of the southeastern United States. Human activities eliminated gopher tortoises from a significant portion of their historic range, but they still occur in Alabama, South Carolina, Louisiana, Mississippi and Georgia, with the majority of the remaining population occurring in Florida, where they are listed as threatened by the Florida Fish and Wildlife Conservation Commission (FWC). The US Fish and Wildlife Service states that listing under the federal Endangered Species Act is warranted and should be extended to cover the tortoise’s entire range .

The gopher tortoise is considered a keystone species because it is a pivotal member of its natural community. It creates burrows and disperses seeds, actions which contribute significantly to upland biodiversity. Gopher tortoises take refuge from extreme temperatures, fire, and predators in their burrows, as do nearly 400 other species, such as the Florida mouse, gopher frog, eastern indigo snake, diamondback rattlesnake, burrowing owl and bobcat. We got an up close and personal look at this aspect of tortoise ecology when an armadillo suddenly ran out of an old burrow and over one of our boots! Most animals retreat down the burrow when people are around, though I do recall an instance of mutual surprise when a rattlesnake ran over my own boot and into hiding.

The burrow survey at Boyd Hill Nature Preserve, one of the last remaining natural areas in urban Pinellas County, Florida was conducted to determine the estimated tortoise population size and demographics, such as average age of the animals. This information can be used to improve habitat management and restoration efforts, and to determine if there is a healthy ratio of young tortoises to adults. Gopher tortoises may live to be over 60 and they usually don’t reach reproductive age and size until at least their teens, and sometimes 20 years of age. Also, they have very few young that survive predation at the egg and infant stage, so protection of all members of the colony is essential. My own research resulted in finding one of the two largest known clutches, 25 eggs, but generally only 8-12 eggs are in the hole dug out and covered over by the female tortoise.

Herpetologist George Heinrich oversaw the Boyd Hill survey, directing volunteers to walk specific management sections in all areas of the preserve that contain appropriate upland habitat. With the other volunteers we lined up in a row evenly spaced apart and walked straight ahead – as well as we could in dense vegetation — in a transect noting any burrows we found.

As we found them, we classified each burrow as active, inactive, or abandoned. The complete survey documented a total of 302 gopher tortoise burrows (239 active and 63 inactive) as well as more than 318 abandoned burrows. Based on this information, experts estimate that 151 tortoises are found on the preserve.

Defenders of Wildlife’s efforts to protect and recover the gopher tortoise is aimed at increasing the amount of habitat available by promoting acquisition of new public lands, working with landowners to establish conservation easements, assuring irresponsible road projects that fragment habitat and lead to roadkill are stopped or modified, and helping shape land use plans that protect important habitat and connections.

In order to reverse the continuing tortoise and habitat loss, Defenders is also trying to increase outreach to the public and land developers and let them know that gopher tortoises are actually a relatively adaptable animal that can coexist with humans.

Some people say that the gopher tortoise has celebrity appeal: its face looks a bit like E.T., the Extra-Terrestrial’s! But these tortoises aren’t just cute: they’re a vital part of Florida’s landscape, and that’s why it’s so important that we monitor and protect them.

Laurie Macdonald is the Florida Program Director at Defenders of Wildlife