Endangered Species Project: the Dusky Gopher Frog

The Dusky Gopher Frog, also known as the Mississippi Gopher Frog, is a rare species of frog. This species grows between 5.6 cm to 10.5 cm long”the female growing typically longer than the male. The tadpoles of this species measure up to 7.4 cm long and are typically a greenish brown color, while the adult frogs are average out to be 8 cm long and darkly colored. This species is named for its dark coloration, warty back, and tendency to hide in the burrows of the gopher tortoise (Wildscreen Arkive). The color of the frog varies between black, grey, or brown exterior complimented with large dark brown spots. According to the Wildscreen Arkive, the dusky gopher frog has a huge head with a remarkably large mouth, which helps it feed on larger prey, and prominent ridges down its back. These frogs are known by their significant croaks on land and underwater and are considered to be an extremely distinct species (International Union for the Conservation of Nature).

Range (Distribution in space):

The Dusky Gopher Frog is native to the southern United States. They were known to be most abundant along the Gulf Coastal Plain near Louisiana, Mississippi, and Alabama; but they have not been seen in Louisiana or Alabama for decades (International Union for the Conservation of Nature). In the most present times, they have been most widely known to be in Glen's Pond which is located Harrison County, Mississippi; however, recently they have been found 50 miles east and 20 miles west at other pond sites (Wildscreen Arkives).

Habitat:

The Dusky Gopher Frog's natural habitats are temperate, sandy longleaf pine forests along the coasts. According to the International Union for the Conservations of Nature, these frogs favor areas with open canopy and abundant ground vegetation. They breed in temporary, shallow ponds that are both submerged and emerged in vegetation (Wildscreen Arkive). These frogs have been known to find shelter in the burrows of gopher tortoise, but if conditions are not favorable, they will also shelter in other small animals or in holes and stumps. Historically, they have been found in Louisiana, Mississippi, Alabama, and Florida areas; however, since endangerment, they have only been found in Glen's pond.

Figure 1 is a depiction of the geographic range of the Dusky Gopher Frog since endangerment (Ritcher and Jensen).

Figure 2 is a depiction of the historic geographic range of the Dusky Gopher Frog and the single remaining population.

Life History and Ecology:

According to the International Union for the Conservations of Nature, the Dusky Gopher Frog spends majority of its life in underground refuge. They have been historically known to breed in these areas between the winter and spring time, typically between the months December and April. The male dusky frogs tend to arrive at the breeding sites earlier than the females in order to protect territories and find a mate. Breeding has been observed to increase during hurricanes and tropical storms within this species.

During breeding the eggs are typically laid on emerging herbaceous vegetation, but due to a loss of habitat, it has been observed that the gopher frogs will lay their eggs in less favorable conditions such as small tress or in areas where there is floating woody debris (Ritcher and Jensen). The females are known to lay a clutch size ranging in the sizes of 500-2,800 eggs in Mississippi; however, in other areas where they occurred, the clutch sizes ranged higher than that of Mississippi. It takes the larvae approximately 81-179 days to develop, and the size of them during this stage varies drastically due to the conditions that they are distributed in (Ritcher and Jensen). According to the Natural Conservancy, they live less than seven years and achieve adequate maturation around 6-8 months in males and 24-36 months in females, which may explain why male sizes are smaller than females. Adult gophers eat upon insects as well as other amphibians that do not prey upon them, while tadpoles tend to eat upon plants.

Table 1 is a snapshot of all Rana species survival percentage with a reference to each study that was found. The Rana Servosa, also known as the Dusky Gopher Frog, had a survival rate of 16-22% in both male and females.

Basis for Classification:

This species has been listed endangered by the state of Mississippi in 1992 and by U.S. Fish and Wildlife Service in 2001 and are considered critically endangered (US Fish and Wildlife Service). These frogs have been listed critically endangered due to a loss of habitat. Over the years the range of this species decreased throughout the areas that it was most known to occur. Recently, this species has only been seen in Mississippi. The last observation of this species in Louisiana was in 1967 and in Alabama, 1922.

According to the International Union for Conservations of Nature (IUCN), some of the major threats to this species include population isolation, urbanization, disease, and lack of suitable habitat. The drastic decrease of range in this species can be a direct result of the destruction of longleaf pine forest and land management practices which have altered the soil horizon, forest litter, herbaceous community, and the occurrence of fallen trees and stumps used as refugia (ICUN). These human activities affect the quality of breeding for the Dusky Gopher Frog because they are destroying the areas in which conditions for survival and breeding are most favorable for this species. The specific habitat requirements known to this species are that they need temporary, fish-free pools in open, grassy forest, and an abundance of burrows in which to shelter. This species, therefore, does not adapt well to changes in its environment, such as the alteration of temporary to permanent ponds, the introduction of predatory fish, and fire suppression, which increases canopy cover and alters ground vegetation which are not ideal for breeding and survival (ICUN). This species is also at risk of predation of

Recommendations:

I think that though this species may seem as if it is doomed, a variety of things can be done to restore favorable conditions for breeding with this species. I saw that one of the problems for the dusky gopher frog is that the abundance of gopher tortoise continuously decreases due to a loss of habitat as well, maybe a reintroduction of these tortoises to the habitat in Glen's Pond could create more favorable conditions. If that may seem too complicated, maybe when the existing gopher frogs breed the next generation, the eggs could be moved to areas that are more suitable for the eggs to survive. Or humans could take more time out to learn about the areas that they find favorable for the activities that they want to carry out and figure out a way to carry out those activities without harming the existing wildlife in those areas.

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