Turtle, Tortoise and Keystone Species

Turtle vs Tortoise:

There are three names for similar animals which live in our region of Florida. The general name for these reptiles is Terrapin (The mascot of the University of Maryland). The specific names are turtle and tortoise. 

I invariably see two varieties of these reptiles: Smooth Soft Shell and Gopher

Every day I spot a Gulf Coast Smooth Soft Shell turtle. (Apalone mutica calvata) I see them swimming and sunning themselves in and about my yard. Their behavior is interesting to watch. They swim just below the surface of the water and extend their heads to breath for a few minutes. The head and neck extension may be up to 8 inches. The body diameter may be up to a meter. The pointed nose is easily identified. They beach themselves on sunny days alone or in groups of three to eight and may spend minutes to hours on land. They usually stay close to the shore and quickly run or slide back into the safety of the water with little provocation. Their eyesight seems to be very good and can spot a threat from at least 30 feet. Note that I used the term turtle to describe them because they are aquatic, have flat shells and wide feet with long claws that are good for swimming. The color of their carapace (upper shell) ranges from brown to green. They may be prey to the alligators and they may predate on the smaller aquatic animals.

Less often, I observe another Terrapin in the lightly wooded areas and fields while walking about especially at Barefoot Beach Park. The Gopher Tortoise (Gopherus polyphemus) is a land-based reptile. This tortoise digs holes in exposed sandy soil with a single opening from 10 to 20 cm in diameter and in the created burrow they lay their eggs. This is the only tortoise native to Florida and it is environmentally critically important. Although they have a 40-to-60-year life span, their reproductive rate is low. The female may not reach reproductive capacity until it is 10 to 20 years old.  They may lay approximately 6 eggs at the entrance of their extensive six foot deep, 12-foot-long burrows. The annual success of a clutch is only 10%. The Gopher Tortoise is relatively small, with a compact ball-like shape. The hard shell has lightly textured plates. The feet are small and have short broad claws and those in front are especially suited for digging.The Gopher tortoise is a keystone mutualist.

The Gopher Tortoise are important to the environment for several reasons. Their digging aerates the soil. More importantly, the burrows provide essential shelter for the survival of hundreds of other animal species like snakes, mice, voles and frogs. These other species, called commensals, use them for shelter and nesting. This is even more vital during and after forest fires where the shelters protect the otherwise exposed animals and without which they would not survive. The entire ecosystem and related species would collapse without the Gopher tortoise. A term applied to this importance is “Keystone Species”. When you see these tortoises, please help to protect them and their environment. Don’t backfill their dens, don’t step on the apron of sand around the entrances to their dens, don’t mow the grass near the den, don’t run them over, if possible, don’t build on their territory. If you want to support the survival of hundreds of other species, thousands of animals and an entire ecosystem, leave them alone.

For more information on these subjectrplease link to University of Florida, box turtles, Turtle owner

I hope that you can distinguish between the turtle and the tortoise. Here is a chart of compared characteristics.

Characteristic	Turtle	Tortoise
Environment	Acquatic	Dry
Foot	Long webbed toes	Short
Carapace	Flatter	Rounder
Longer lived	Shorter	Longer

Keystone Species:

It is extraordinarily important to understand and discover Keystone Species. To leave no doubt about understanding what this means I have added the following links which I encourage you to investigate. 

“A keystone species is understood to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This definition links the community importance of keystone species to a specific ecosystem process.” ^LINK

For vivid examples of the role of keystone species in an ecosystem go to these linked sites from National Geographic and the Ecologic Society, and Wildlife habitats.

https://www.nationalgeographic.org/encyclopedia/keystone-species/

https://www.nationalgeographic.org/article/role-keystone-species-ecosystem/

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/keystone-species

Link: https://www.ecologyandsociety.org/vol7/iss1/resp11/

Report gopher tortoise locations using this app, http://myfwc.com/wildlifehabitats/managed/gopher-tortoise/app/.

We will discuss other turtles in subsequent postings including those living in fresh, brackish and swamp water as well as sea fairing species.

#Tortoise #Turtle #Soft Shell turtle #Gopher tortoise #Keystone species #Mutualist #Terrapin #Ecosystem #commensal #mutualist #Epicollect5 Observation 8

Receive new content direct to your in box, please enter your email address, click on subscribe.