Gopherus polyphemus
Encyclopedia
The gopher tortoise is a species
of the Gopherus
genus
native to the southeastern United States
. The gopher tortoise is seen as a keystone species
because it digs burrows that provide shelter for 360 other animal species. They are threatened by predation and habitat destruction
.
The gopher tortoise is a representative of the genus
Gopherus, which contains the only tortoises native to North America. This species of gopher tortoise is the state reptile of Georgia and the state tortoise of Florida.
, shovel-like forelimbs, and a gular projection on a yellowish, hingeless plastron.
Male gopher tortoises have two subdentary scent gland
s under the chin
. Males are distinguished from females by their concave plastron and longer tail, but the sexes can be difficult to tell apart.
of Florida
, but its range
also extends to Georgia
, North Carolina
, Alabama
, Mississippi
, southeast Louisiana
, and the southernmost corner of South Carolina
.
, and terrestrial legumes. They also eat mushrooms, as well as fruits such as gopher apple
, pawpaw
, blackberries
, and saw palmetto berries. In addition, gopher tortoises eat flowers from the genera Cnidoscolus
(nettles), Tillandsia
(Spanish
and ball moss
), Richardia
, and Dyschoriste
. Juvenile tortoises tend to eat more legumes, which are higher in protein, and fewer grasses and tough, fibrous plants than mature tortoises. Gopher tortoises have been known to scavenge carrion and eat excrement
. As gopher tortoises usually get water from the food they eat, they usually only drink standing water in times of extreme drought.
Gopher tortoises like other tortoises of the genus Gopherus, are known for their digging ability. Gopher tortoises spend most of their time in long burrows, up to 14.5 metres (47.6 ft) in length and 3 metres (9.8 ft) deep. In these burrows, the tortoises are protected from summer heat, winter cold, fire
, and predators. The burrows are especially common in longleaf pine
savannas, where the tortoises are the primary grazers, playing an essential role in their ecosystem. Except during breeding season, gopher tortoises are solitary animals, inhabiting a small home range. Within their range they dig several burrows. On average, each gopher tortoise needs about 4 acres (16,187.4 m²) to live.
The gopher tortoise reaches maturity at about 10–15 years of age, when their shells are around 9 inches (22.9 cm) long. They may mate from February through September, with a peak throughout May and June. Females may lay clutches of 3-14 eggs, depending on body size, in a sandy mound very close to the entrance of their burrow.
Ninety percent of clutches may be destroyed by predators such as armadillo
s, raccoon
s, fox
es, skunk
s and alligator
s before the eggs
hatch, and less than 6% of eggs are expected to grow into tortoises that live one year or more after hatching.
Since July 7, 1987, the U.S. Fish and Wildlife Service has listed Gopherus polyphemus as "Threatened" wherever the tortoises are found west of the Mobile
and Tombigbee
Rivers in Alabama, Mississippi, and Louisiana. Its status is listed as "Under Review" in Florida and in other locations. On November 9, 2009, the U.S. Fish and Wildlife Service proposed rulemaking to include the eastern population of Gopherus polyphemus in the List of Threatened Wildlife. G. polyphemus appears on the IUCN Red List
as a "Vulnerable" species; however, it has not been assessed for the purposes of this list since 1996. In July 2011, United States Fish & Wildlife Service (USFWS) determined that listing the eastern population of the tortoise as Threatened under the Endangered Species Act is warranted, however, it is precluded from doing so at this time due to higher priority actions and a lack of sufficient funds to commence proposed rule development. In the interim period of time the USFWS will place the eastern population of the tortoise on its candidate species list until sufficient funding is available to initiate a proposed listing rule.
The University of Florida Conservation Clinic Center for Governmental Responsibility Levin College of Law describe five main threats to the tortoise population, they are: (1) Habitat loss through human development, (2) habitat loss through poor supervision, (3) human desire to use it as a pet or meat, (4) relocation causing population disruption, and (5) disease caused by relocation.
Gopher tortoises are known as a keystone species
.
The Florida Fish and Wildlife Conservation Commission states the gopher tortoise provides refuge for as many as 350 to 400 species. The burrows are used for feeding, resting, reproduction, and protection from temperature extremes, moisture loss,
and predators. These species include gopher frogs
(Rana capito), several species of snake
, such as the eastern indigo snake (Drymarchon corais couperi), small invertebrates, and burrowing owl
s (Athene cunicularia). Therefore, conservation efforts focused on the gopher tortoise aid these species as well.
Conversion of gopher tortoise habitat to urban areas, croplands, and pasture
, along with adverse forest management practices, has drastically reduced the historic range of the gopher tortoise. The taking of gopher tortoises for sale or use as food or pets has also had a serious effect on some populations. The seriousness of the loss of adult tortoises is magnified by the length of time required for tortoises to reach maturity and their low reproductive rate. According to the website of the Brevard Zoo in Melbourne, Florida, current estimates of human predation and road mortality alone are at levels that could offset any annual addition to the population, and sightings of gopher tortoises have become rare in many areas, and the ones sighted are much smaller than in the past. A number of other species also prey upon gopher tortoises, including the raccoon
, which is the primary egg and hatchling predator, gray fox
es, striped skunk
s, nine-banded armadillo
s, dogs, snakes, and raptors. Red imported fire ant
s also have been known to prey on hatchlings. A 1980 report indicated clutch and hatchling losses often approach 90 percent
In the past, many gopher tortoises in Florida have been destroyed as developers could acquire Incidental Take Permit
s to build in the gopher tortoises' natural habitat without regard to the safety of the tortoises. This has changed. On July 31, 2007, a new policy was implemented requiring developers to relocate tortoises. Starting on April 22, 2009, three types of permits were available in Florida for developers wishing to build on gopher tortoise habitat. Two of these permits allow for the relocation of gopher tortoises, either to some other place on the site being used for construction, or to a recipient site which has been certified by the Florida Fish and Wildlife Conservation Commission
. The third type of permit allows for temporary relocation of tortoises while major utility lines are installed. In the third case, the tortoises are returned to their habitat after construction is complete.
In Mississippi
, along State Route 63, chain link fences
were built to prevent gopher tortoise mortality from traffic. These fences, made from heavy gauge wire
for durability, are three feet high and are buried one foot below the surface. The fences have "turnarounds" at either end, which are angled fences that redirect tortoises back into the area from which they come. As of 2003, no roadside gopher tortoise deaths had been reported along Route 63 since the construction of the fences.
Tortoises not only withstand predations from other animals, but they also have to withstand predations from humans as well. People have eaten gopher tortoises for thousands of years. During the Great Depression, Gopher tortoise was known as the “Hoover Chicken” because they were eaten by poor people out of work. Some people see gopher tortoise meat as a delicacy, or as simply a free source of meat. Although it is now illegal to hunt gopher tortoises or possess their meat or shells, illegal hunting continues to take place at an unsustainable rate, with some colonies being driven to extinction. In 2006, police uncovered “five pounds of tortoise meat in [a] man’s refrigerator” after they spotted empty tortoise shells along freeway in Florida. In nineteen counties in Alabama, tortoise is listed as “game species,” though one with "no open season."
Gopher tortoises have been kept as pets, preventing them from reproducing in their local population
s. Captured gopher tortoises can be raced in tortoise races
. This practice was banned in Florida in 1989. Moving a tortoise can lead to harmful consequences to the environment from which it came, because the tortoise is often not returned to the same place where it was found. Also, as tortoise racing involves several tortoises in close proximity to one another, diseases can easily spread from one tortoise to another. If an infected captive tortoise is then returned to the environment, other tortoises may be infected.
One of the most suitable habitats for Gopher tortoise is the longleaf pine ecosystem, which is provides suitable well-drained and sandy soils for tortoises to inhabit. Longleaf pine forests include abundant low herbaceous plant growth and open canopy/space for tortoise’s eggs to incubate. Since European settlement, longleaf pine decreased in area by an estimated of 96%, which has contributed to an 80% decrease in population densities of gopher tortoise. This means that there is only 4% of longleaf pine remaining.
Gopher tortoise could potentially lose 700 acres (2.8 km²) of its habitats if Florida’s population doubles. Due to land development and human activity, 7000000 acres (28,328 km²) of land, which is the size of Vermont, will be developed. 3000000 acres (12,140.6 km²) of agricultural lands and 2700000 acres (10,926.5 km²) of unused land will be developed. Because of this, there will be more competition for water resources between the animals and human residents. The low reproductive rate of the tortoise makes it more vulnerable impact to the decline of longleaf ecosystem. This will potentially lead to the extinction of the tortoise.
agassizii and iridovirus
and herpes virus
es. Symptoms of URTDs include serous, mucoid, or purulent discharge from the nares, excessive tearing to purulent ocular discharge, conjunctivitis, and edema of the eyelids and ocular glands. M. agassizii is known to exist in tortoises without showing obvious symptoms. The antibiotic enrofloxacin
has been used to treat bacterial URTDs in G. polyphemus.
Although long term studies indicate URTDs can cause population declines in desert tortoise populations 10–15 years after initial infection, studies of such length have not been performed on G. polyphemus. One study, which observed G. polyphemus tortoises in Florida from 2003–06, returned the unexpected observation that tortoises which were seropositive
for URTD antibodies were less likely to die over that time than seronegative
tortoises. However, the habitats of more seropositive populations had more remains of dead tortoises. The investigators offered the explanation that seropositive tortoises had survived an initial infection, then developed chronic disease. This evidence may imply a possible acute
effect on mortality, followed by chronic
disease in surviving individuals. Further studies are needed to more fully understand the effects of URTD on this species.
Conserving these forests would provide the natural habitats Gopher tortoises need.
Successful reforestation efforts have been made. According to the Environmental Defense Fund’s website, environmentalists and private land owners are working together to maintain the wildlife habitat while maintaining crops productivity. Groups provide assistance to private landowners to ensure funding for conservation incentives to landowners who are willing to preserve wildlife on their soil. Most lands in the East are privately owned. Landowners used “prescribed burns’ to restore favorable habitat conditions. Prescribed burns managed by the Safe Harbor Agreement benefits U.S. Fish & Wildlife, serve under Federal Endangered Species Act help reduces and prevents the amount of invasive species that are threatening to the tortoise; Invasive species such as the (1) cogongrass aka Imperata cylindrica and (2) Fire ant
s disrupt gopher tortoise’s habitat and kill tortoise eggs can be controlled. Prescribed fire is one method to provide sufficient ground for the tortoise and its eggs to survive and maintain biodiversity.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of the Gopherus
Gopherus
Gopherus is a genus of tortoises commonly referred to as gopher tortoises. The gopher tortoise is grouped with land tortoises that originated 60 million years ago, in North America...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
native to the southeastern United States
Southeastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....
. The gopher tortoise is seen as a keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
because it digs burrows that provide shelter for 360 other animal species. They are threatened by predation and habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
.
The gopher tortoise is a representative of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Gopherus, which contains the only tortoises native to North America. This species of gopher tortoise is the state reptile of Georgia and the state tortoise of Florida.
Anatomy and physiology
Gopher tortoise can be identified easily based on their appearance. A typical tortoise has a large head. Their skin color ranges from light to grayish or dark brown skin. Their long front legs are for burrowing, unlike their behind legs which are shorter. Their upper shell, called a “carapace” is yellowish brown. The average size ranges from 107 mm to 240 mm in length. The gopher tortoise can have a shell up to 37 centimeters or 14.6 inches in length. On average, individuals are a bit less than one foot long. The gopher tortoise's carapace is a solid dark-brown to grayish color. Hatchlings are more yellowish in color. They have hind legs reminiscent of those of an elephantElephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
, shovel-like forelimbs, and a gular projection on a yellowish, hingeless plastron.
Male gopher tortoises have two subdentary scent gland
Scent gland
Scent glands are found in the genital area of most mammals and in various other parts of the body, such as the underarms of humans and the preorbital glands of deer and muskox. They produce a semi-viscous fluid which contains pheromones. These odor-messengers indicate information such as status,...
s under the chin
Chin
In the human anatomy, the chin is the lowermost part of the face.It is formed by the lower front of the mandible.People show a wide variety of chin structures. See Cleft chin....
. Males are distinguished from females by their concave plastron and longer tail, but the sexes can be difficult to tell apart.
Ecology
The gopher tortoise is common in the stateU.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, but its range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
also extends to Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...
, southeast Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
, and the southernmost corner of South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
.
Diet
Gopher tortoises are herbivore scavengers. Their diets contains over 300 species of plants. They consume a very wide range of plants, but mainly eat broad-leaved grasses, wiregrassAristida stricta
Aristida stricta is a warm-season grass, native to North America, that dominates understory vegetation in sandhills and flatwoods coastal plain ecosystems of the Southeastern United States...
, and terrestrial legumes. They also eat mushrooms, as well as fruits such as gopher apple
Licania michauxii
Licania michauxii, commonly known as Gopher Apple, is an evergreen shrub. It grows in the sandhills of peninsular Florida as well as coastal Mississippi and Georgia, and its fruit is eaten by wildlife and is being used in cancer research. It fruit is a food source for the gopher tortoise....
, pawpaw
Asimina triloba
Asimina triloba, the pawpaw, paw paw, paw-paw, or common pawpaw, is a species of Asimina in the same plant family as the custard-apple, cherimoya, sweetsop, ylang-ylang and soursop...
, blackberries
Blackberry
The blackberry is an edible fruit produced by any of several species in the Rubus genus of the Rosaceae family. The fruit is not a true berry; botanically it is termed an aggregate fruit, composed of small drupelets. The plants typically have biennial canes and perennial roots. Blackberries and...
, and saw palmetto berries. In addition, gopher tortoises eat flowers from the genera Cnidoscolus
Cnidoscolus
Cnidoscolus is a plant genus of the family Euphorbiaceae. The name is derived from the Greek words κνίδη , meaning "nettle," and σκολος , meaning "thorn" or "prickle."-Selected species:...
(nettles), Tillandsia
Tillandsia
Tillandsia is a genus of around 540 species in the Bromeliad family , found in the forests, mountains, and deserts, of Central and South America, and Mexico and the southern United States in North America....
(Spanish
Spanish Moss
Spanish moss is a flowering plant that grows upon larger trees, commonly the Southern Live Oak or Bald Cypress in the southeastern United States....
and ball moss
Tillandsia recurvata
Tillandsia recurvata, commonly known as Ball Moss, is a flowering plant that grows upon larger host plants. It grows well in areas with low light, little airflow, and high humidity, which is commonly provided by southern shade trees, often the Southern Live Oak...
), Richardia
Richardia
Richardia is a small genus of about 15 species of flowering plants in the family Rubiaceae, native to tropical to warm temperate regions of the Americas, with one species also native to Fiji in the Pacific Ocean. They are mostly annual plants, a few species being herbaceous perennial...
, and Dyschoriste
Dyschoriste
Dyschoriste is a genus of flowering plants in the acanthus family, Acanthaceae. Members of the genus are commonly known as snakeherb.-Selected species:*Dyschoriste angusta Small – Pineland Snakeherb...
. Juvenile tortoises tend to eat more legumes, which are higher in protein, and fewer grasses and tough, fibrous plants than mature tortoises. Gopher tortoises have been known to scavenge carrion and eat excrement
Coprophagia
Coprophagia or coprophagy is the consumption of feces, from the Greek κόπρος copros and φαγεῖν phagein . Many animal species practice coprophagia as a matter of course; other species do not normally consume feces but may do so under unusual conditions...
. As gopher tortoises usually get water from the food they eat, they usually only drink standing water in times of extreme drought.
Burrowing
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
, and predators. The burrows are especially common in longleaf pine
Longleaf Pine
Pinus palustris, commonly known as the Longleaf Pine, is a pine native to the southeastern United States, found along the coastal plain from eastern Texas to southeast Virginia extending into northern and central Florida....
savannas, where the tortoises are the primary grazers, playing an essential role in their ecosystem. Except during breeding season, gopher tortoises are solitary animals, inhabiting a small home range. Within their range they dig several burrows. On average, each gopher tortoise needs about 4 acres (16,187.4 m²) to live.
Breeding and reproduction
Sexual reproduction involves courtship rituals between the male and the female tortoises. During the mating season between April and November, females lay their eggs in the open; about 1-25 eggs incubate underground for 100 days. The sex of the eggs is determined by the temperature where they are incubated in a nest laid below sand. If the sand is over 30 degrees Celsius, it’s a female and if below 30 degrees Celsius, the egg is a male. Incubation period can last from 80–90 days in Florida and 110 days in South Carolina. Gopher tortoises can live up to 40 years.The gopher tortoise reaches maturity at about 10–15 years of age, when their shells are around 9 inches (22.9 cm) long. They may mate from February through September, with a peak throughout May and June. Females may lay clutches of 3-14 eggs, depending on body size, in a sandy mound very close to the entrance of their burrow.
Ninety percent of clutches may be destroyed by predators such as armadillo
Armadillo
Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...
s, raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
s, fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es, skunk
Skunk
Skunks are mammals best known for their ability to secrete a liquid with a strong, foul odor. General appearance varies from species to species, from black-and-white to brown or cream colored. Skunks belong to the family Mephitidae and to the order Carnivora...
s and alligator
Alligator
An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator and the Chinese alligator ....
s before the eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
hatch, and less than 6% of eggs are expected to grow into tortoises that live one year or more after hatching.
Conservation concerns
Mobile River
The Mobile River is located in southern Alabama in the United States. Formed out of the confluence of the Tombigbee and Alabama rivers, the approximately river drains an area of of Alabama, with a watershed extending into Mississippi, Georgia, and Tennessee. Its drainage basin is the...
and Tombigbee
Tombigbee River
The Tombigbee River is a tributary of the Mobile River, approximately 200 mi long, in the U.S. states of Mississippi and Alabama. It is one of two major rivers, along with the Alabama River, that unite to form the short Mobile River before it empties into Mobile Bay on the Gulf of Mexico...
Rivers in Alabama, Mississippi, and Louisiana. Its status is listed as "Under Review" in Florida and in other locations. On November 9, 2009, the U.S. Fish and Wildlife Service proposed rulemaking to include the eastern population of Gopherus polyphemus in the List of Threatened Wildlife. G. polyphemus appears on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
as a "Vulnerable" species; however, it has not been assessed for the purposes of this list since 1996. In July 2011, United States Fish & Wildlife Service (USFWS) determined that listing the eastern population of the tortoise as Threatened under the Endangered Species Act is warranted, however, it is precluded from doing so at this time due to higher priority actions and a lack of sufficient funds to commence proposed rule development. In the interim period of time the USFWS will place the eastern population of the tortoise on its candidate species list until sufficient funding is available to initiate a proposed listing rule.
The University of Florida Conservation Clinic Center for Governmental Responsibility Levin College of Law describe five main threats to the tortoise population, they are: (1) Habitat loss through human development, (2) habitat loss through poor supervision, (3) human desire to use it as a pet or meat, (4) relocation causing population disruption, and (5) disease caused by relocation.
Gopher tortoises are known as a keystone species
Keystone species
A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and...
.
The Florida Fish and Wildlife Conservation Commission states the gopher tortoise provides refuge for as many as 350 to 400 species. The burrows are used for feeding, resting, reproduction, and protection from temperature extremes, moisture loss,
and predators. These species include gopher frogs
Gopher Frog
The Gopher Frog is a species of frog in the Ranidae family. It is endemic to the Southeastern United States. It primarily inhabits the threatened sandhill communities, flatwoods, and scrub in the Atlantic coastal plain, where it is usually found near ponds.-Subspecies:Its two subspecies include...
(Rana capito), several species of snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
, such as the eastern indigo snake (Drymarchon corais couperi), small invertebrates, and burrowing owl
Burrowing Owl
The Burrowing Owl is a tiny but long-legged owl found throughout open landscapes of North and South America. Burrowing Owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open dry area with low vegetation. They nest and roost in burrows, such as those excavated...
s (Athene cunicularia). Therefore, conservation efforts focused on the gopher tortoise aid these species as well.
Conversion of gopher tortoise habitat to urban areas, croplands, and pasture
Pasture
Pasture is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep or swine. The vegetation of tended pasture, forage, consists mainly of grasses, with an interspersion of legumes and other forbs...
, along with adverse forest management practices, has drastically reduced the historic range of the gopher tortoise. The taking of gopher tortoises for sale or use as food or pets has also had a serious effect on some populations. The seriousness of the loss of adult tortoises is magnified by the length of time required for tortoises to reach maturity and their low reproductive rate. According to the website of the Brevard Zoo in Melbourne, Florida, current estimates of human predation and road mortality alone are at levels that could offset any annual addition to the population, and sightings of gopher tortoises have become rare in many areas, and the ones sighted are much smaller than in the past. A number of other species also prey upon gopher tortoises, including the raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
, which is the primary egg and hatchling predator, gray fox
Gray Fox
The gray fox is a mammal of the order Carnivora ranging throughout most of the southern half of North America from southern Canada to the northern part of South America...
es, striped skunk
Striped Skunk
The striped skunk, Mephitis mephitis, is an omnivorous mammal of the skunk family Mephitidae. Found over most of the North American continent north of Mexico, it is one of the best-known mammals in Canada and the United States.-Description:...
s, nine-banded armadillo
Nine-banded Armadillo
The nine-banded armadillo , or the nine-banded, long-nosed armadillo, is a species of armadillo found in North, Central, and South America, making it the most widespread of the armadillos...
s, dogs, snakes, and raptors. Red imported fire ant
Red imported fire ant
See main article Fire ant.The red imported fire ant , or simply RIFA, is one of over 280 species in the widespread genus Solenopsis...
s also have been known to prey on hatchlings. A 1980 report indicated clutch and hatchling losses often approach 90 percent
In the past, many gopher tortoises in Florida have been destroyed as developers could acquire Incidental Take Permit
Incidental Take Permit
An incidental take permit is a permit issued under Section 10 of the Federal Endangered Species Act to private, non-federal entities undertaking otherwise lawful projects that might result in the take of an endangered or threatened species...
s to build in the gopher tortoises' natural habitat without regard to the safety of the tortoises. This has changed. On July 31, 2007, a new policy was implemented requiring developers to relocate tortoises. Starting on April 22, 2009, three types of permits were available in Florida for developers wishing to build on gopher tortoise habitat. Two of these permits allow for the relocation of gopher tortoises, either to some other place on the site being used for construction, or to a recipient site which has been certified by the Florida Fish and Wildlife Conservation Commission
Florida Fish and Wildlife Conservation Commission
The Florida Fish and Wildlife Conservation Commission is a Florida government agency charged with managing the state's fish and wildlife resources, regulating Florida's fisheries and wildlife, and enforcing related laws...
. The third type of permit allows for temporary relocation of tortoises while major utility lines are installed. In the third case, the tortoises are returned to their habitat after construction is complete.
In Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...
, along State Route 63, chain link fences
Chain-link fencing
A chain-link fence is a type of woven fence usually made from galvanized or LLDPE-coated steel wire...
were built to prevent gopher tortoise mortality from traffic. These fences, made from heavy gauge wire
Wire
A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...
for durability, are three feet high and are buried one foot below the surface. The fences have "turnarounds" at either end, which are angled fences that redirect tortoises back into the area from which they come. As of 2003, no roadside gopher tortoise deaths had been reported along Route 63 since the construction of the fences.
Human Predation
Gopher tortoises have been kept as pets, preventing them from reproducing in their local population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
s. Captured gopher tortoises can be raced in tortoise races
Turtle racing
Turtle racing is a popular event in which participants typically place turtles in the center of a circle and watch them walk around until one of them crosses out of the circle...
. This practice was banned in Florida in 1989. Moving a tortoise can lead to harmful consequences to the environment from which it came, because the tortoise is often not returned to the same place where it was found. Also, as tortoise racing involves several tortoises in close proximity to one another, diseases can easily spread from one tortoise to another. If an infected captive tortoise is then returned to the environment, other tortoises may be infected.
Climate Change
Climate change poses another challenge for the Gopher tortoise through alteration of habitat. According to the Florida’s Fish and Wildlife Conservation Fish and Commission, rising temperature and change in rainfall patterns may increase the numbers of invasive species which if more adapted to these environmental changes could drive out native plants essential for tortoise’s diet. Invasive species can cause habitat fragmentation and increase stress to Gopher tortoises and other native animals. Warmer temperature may cause sea level to rise and more storms to occur. Extreme periods of rainfall and drought will cause fewer lands to become available. There will also be an increase or decrease in water availability. One meter rise in sea level leads to loss of 20% of existing conservation lands and 30% of the natural habitats. As the sea level rises, it will move storms closer to land and affect both coastal and marine environments. Species may move inland as less land is accessible. This can increase the spread of diseases or disrupt food cycles and reproduction.Habitat Loss
In 1987, human urbanization and various human activities in Mississippi, Louisiana, and Alabama caused dramatic declines in the tortoise population, and the U.S. Fish and Wildlife Service listed them as “endangered.” Even though the population declined in Florida, Georgia, and South Carolina, they were not yet listed as threatened at the time. However, in recent years, habitat loss is increasing as southern states continue to experience human population growth, and expand on highway road construction. The southeast has had a 20% increase in human population between 1990 and 2000.One of the most suitable habitats for Gopher tortoise is the longleaf pine ecosystem, which is provides suitable well-drained and sandy soils for tortoises to inhabit. Longleaf pine forests include abundant low herbaceous plant growth and open canopy/space for tortoise’s eggs to incubate. Since European settlement, longleaf pine decreased in area by an estimated of 96%, which has contributed to an 80% decrease in population densities of gopher tortoise. This means that there is only 4% of longleaf pine remaining.
Gopher tortoise could potentially lose 700 acres (2.8 km²) of its habitats if Florida’s population doubles. Due to land development and human activity, 7000000 acres (28,328 km²) of land, which is the size of Vermont, will be developed. 3000000 acres (12,140.6 km²) of agricultural lands and 2700000 acres (10,926.5 km²) of unused land will be developed. Because of this, there will be more competition for water resources between the animals and human residents. The low reproductive rate of the tortoise makes it more vulnerable impact to the decline of longleaf ecosystem. This will potentially lead to the extinction of the tortoise.
Diseases
Gopher tortoises are known to contract upper respiratory tract diseases (URTDs) caused by various microorganisms, including the bacterium MycoplasmaMycoplasma
Mycoplasma refers to a genus of bacteria that lack a cell wall. Without a cell wall, they are unaffected by many common antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis. They can be parasitic or saprotrophic. Several species are pathogenic in humans,...
agassizii and iridovirus
Iridoviridae
Iridoviridae are a family of viruses with double stranded DNA genomes. The name is derived from Iris the Greek goddess of the rainbow. This name was chosen because of the "rainbow like" iridescence observed in heavily infected insects and pelleted samples of invertebrate iridoviruses.-Taxonomy:The...
and herpes virus
Herpesviridae
The Herpesviridae are a large family of DNA viruses that cause diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word herpein , referring to the latent, recurring infections typical of this group of viruses...
es. Symptoms of URTDs include serous, mucoid, or purulent discharge from the nares, excessive tearing to purulent ocular discharge, conjunctivitis, and edema of the eyelids and ocular glands. M. agassizii is known to exist in tortoises without showing obvious symptoms. The antibiotic enrofloxacin
Enrofloxacin
Enrofloxacin is a fluoroquinolone antibiotic sold by the Bayer Corporation under the trade name Baytril. Enrofloxacin is currently FDA-approved for treatment of individual pets and domestic animals in the United States...
has been used to treat bacterial URTDs in G. polyphemus.
Although long term studies indicate URTDs can cause population declines in desert tortoise populations 10–15 years after initial infection, studies of such length have not been performed on G. polyphemus. One study, which observed G. polyphemus tortoises in Florida from 2003–06, returned the unexpected observation that tortoises which were seropositive
Serostatus
Serostatus is a term used to refer to the presence or absence of specific substances in the blood serum. Most commonly, this medical test is looking for specific antibodies in an effort to diagnose a particular disease....
for URTD antibodies were less likely to die over that time than seronegative
Serostatus
Serostatus is a term used to refer to the presence or absence of specific substances in the blood serum. Most commonly, this medical test is looking for specific antibodies in an effort to diagnose a particular disease....
tortoises. However, the habitats of more seropositive populations had more remains of dead tortoises. The investigators offered the explanation that seropositive tortoises had survived an initial infection, then developed chronic disease. This evidence may imply a possible acute
Acute (medicine)
In medicine, an acute disease is a disease with either or both of:# a rapid onset, as in acute infection# a short course ....
effect on mortality, followed by chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
disease in surviving individuals. Further studies are needed to more fully understand the effects of URTD on this species.
Longleaf Forest Conservation
Since the longleaf ecosystem is required for the maintenance of the Gopher tortoise, conservation efforts are needed to maintain this endangered ecosystem. The longleaf pine ecosystem provides extreme conditions such as “nutrient” deprived soil and “sandy sites” for gopher’s habitation. It takes 100 to 150 years for longleaf pine to grow and can live to over 300 years old.Conserving these forests would provide the natural habitats Gopher tortoises need.
Successful reforestation efforts have been made. According to the Environmental Defense Fund’s website, environmentalists and private land owners are working together to maintain the wildlife habitat while maintaining crops productivity. Groups provide assistance to private landowners to ensure funding for conservation incentives to landowners who are willing to preserve wildlife on their soil. Most lands in the East are privately owned. Landowners used “prescribed burns’ to restore favorable habitat conditions. Prescribed burns managed by the Safe Harbor Agreement benefits U.S. Fish & Wildlife, serve under Federal Endangered Species Act help reduces and prevents the amount of invasive species that are threatening to the tortoise; Invasive species such as the (1) cogongrass aka Imperata cylindrica and (2) Fire ant
Fire ant
Fire ants are a variety of stinging ants with over 285 species worldwide. They have several common names, including ginger ants, tropical fire ants and red ants.- Appearance :...
s disrupt gopher tortoise’s habitat and kill tortoise eggs can be controlled. Prescribed fire is one method to provide sufficient ground for the tortoise and its eggs to survive and maintain biodiversity.
External links
- Enchanted Forest Nature Sanctuary: Gopher tortoise
- Gopherus Polyphemus Blog of the Digital Library of Georgia