Paper for the elective course “Wildlife and ecology”

9.5.2003

Gene Pools and Endangered Species:
The Plight of the Florida Panther

 

By Gil Ismach

 

In the last 400 years, more than 700 of Earth’s animals and plant species have become extinct. In the U.S alone, at least 30 species have suffers extinction in the last decade. In addition, hundreds of genetically distinct plant and animal species are now endangered. The rate of species and ecosystem losses are accelerating rapidly and are predicted to continue unabated during this millennium too. This dramatic loss of biological diversity is a direct consequence of human activity. As we human increase our numbers and spread over Earth’s surface, we harness more of Earth’s resources  for our use, clearing forests, polluting the water and inexorably and permanently altering Earth’s natural balance.

            Although the destruction continues, we are beginning to understand the implications of our actions and to make efforts to save some of Earth’s more endangered life forms. However, despite our best efforts to save threatened species, we often intercede after population numbers have suffered sever declines. This means that much of the genetic diversity that existed in the species is lost, and the population must be rebuilt from a reduced gene pool. The resulting genetic uniformity can reduce fitness, as well as exposing genetic diseases. This reduced fitness may further deplete the number of the threatened animal or plant, and the population spirals downward to extinction.

            The story of the Florida panther provides a poignant example of how an animal can be brought to verge of extinction, and how the efforts of scientists and general public might restore this creature to a healthy place in the ecosystem. The Florida panther, Felis Concolor Coryui, is one of 30 subspecies of cougar (puma or mountain lion), and is one of the most endangered mammal in the world. Florida panthers once roamed the southeast corner of North America, from South Carolina and Arkansas to the southern tip of Florida. As people settled the southern and eastern states, panthers were killed as potential threats to livestock and humans. In the 19^th and 29^th centuries, panthers were killed by hunting, highway collisions, poisoning, and loss of habitat. Today, only 30-50 Florida panthers remain, isolated in southern Florida in the Big Cypress Swamp and Everglades National Park region. Population projection indicate that the Florida panther will be extinct in 25 years.

            The geographical isolation and inbreeding of the remaining Florida panthers have resulted in the loss of genetic variability and declined health. The panther has been separated  from other cougars subspecies for 15 to 25 generations. As a result, they have the lowest levels of genetic heterozygosity of any subspecies of cougar. This loss of genetic diversity has manifest itself in the appearance of several sever genetic defects. Almost 80 % in the Big Cypress region show a rare heritable (autosomal dominant or sex-linked recessive) condition known as cryptorchidism, manifested as the failure of one or both testicles to descend. This defect is associated with the lower testosterone levels and reduced sperm count. Florida panther males in general have the poorest seminal quality of any cat species, with approximately 93% abnormal sperm. Life-threatening congenital heart defects are also appearing in the panther population, possibly due to an autosomal dominant gene defect. In addition, some immune deficiencies are appearing, and these may have a genetic component. Reduced immunity could wipe out the population. Other less serious genetic features have appeared, such as kink in the tail and a whorl of fur on the back.

            Over the last two decades, a faint glimmer of hope has appeared for the Florida panthers. Federal and state agencies, as well as private individuals, are implementing a “Florida Panther Recovery Program”. The goal of the plan is to have 130 breeding animals (wild and captive) by the year 2004 and 500 by the year 2015. If successful, the plan would grant the panther a 95% probability of survival while retaining 90% of its genetic diversity. The plan is multifaceted and includes a captive breeding program, strict protection, increasing and improving the panther habitat, and education the public and private landowners. Wildlife underpasses have been constructed on highway fatalities (which count for half of the panthers deaths). In 1995, a genetic restoration program began. In order to introduce genetic diversity into the Florida panther population and to retard the detrimental effects of inbreeding, eight female wild Texas panthers (a related subspecies from western Texas) were released into Florida panther territory. Two of the females have been killed, one from an automobile collision and one from gunshot wounds. However, the remaining Texas females have given birth to 12 healthy kittens (as of summer 1998) and one of these F1 offspring has produced three kittens of her own. None of the kittens appear to have the “kinked” tail of the inbred Florida panther.

            The survival of the Florida panther is far from certain. Its recovery will require years of monitoring and frequent intervention. In addition, people must be willing to share their land with the wild creatures that no not directly further their self-interests. However, as public support for the return of the Florida panther has been strong, there may be hope for this unique, impressive animal.

 

 

References:

Website: The Florida Panther Society

http;/members.atlantic.net/-oldfla/panther