Gopher Tortoises are a threatened species that lives throughout pine forests of Florida, where they dig deep burrows to use as their homes. The leading threat to gopher tortoises in Florida is human expansion of cities and suburbs, which displace the tortoises and destroy the burrows they create. Given the extent of urbanization in Miami, it's not a surprise that the tortoises are rare here.
A new study led by Zoo Miami's Conservation and Research Department focuses on the last populations of gopher tortoises left in Miami-Dade County. One population is within the Richmond pine rocklands (surrounding Zoo Miami), and another at the Deering Estate.
The study compared habitat features at tortoise burrows and random points in pine rockland habitat to assess the habitat requirements in pine rocklands. The pine rocklands are a habitat unique to Miami-Dade County, and are an unusual habitat for the tortoise because tortoises generally prefer sandy soils over rocky limestone soils. However, the team found that the tortoises are able to find sandy patches in the rocky soils to dig their burrows. In addition to deep sandy pockets, the tortoises require open canopy habitats with little leaf litter. Land managers can't effectively create deeper or sandier soil, but they can target areas with deep soils for prescribed burns - a management strategy that lowers canopy cover and litter depth.
"Gopher Tortoises in Miami-Dade County are at the forefront of threats from urbanization and warming climate," says Dr. Steven Whitfield, a conservation biologist at Zoo Miami who leads the gopher tortoise research. "We were concerned that the geology of the pine rocklands may also be difficult for the tortoises, but it's good to see that they don't seem troubled by rocky soils."
Gopher tortoises are known as a keystone species, a species that is critical to the function of habitats where they live. "More than 400 species of animals have been seen using the burrows created by gopher tortoises. Humans could learn a lot from them about how to coexist with other species," says Dr. Whitfield.
Ongoing conservation research is focused on developing management strategies for tortoises in areas encroached by urbanization, and on understanding impacts of warming climate on the tortoises.
If you see a gopher tortoise in or around Miami, you can help by reporting it to FWC's gopher tortoise reporting website.
The study was published in the journal Ichthyology and Herpetology.
Burrow Characteristics and Habitat Associations of Gopher Tortoises in Urban Pine Rockland Reserves (Miami, Florida, USA)
Steven M. Whitfield, Daniel Valle, Adrian Figueroa, Brianna Chin, Hugo Bravo-Gallegos, Frank Leone
Ichthyology & Herpetology 110 (1), 22-32. https://doi.org/10.1643/h2020168