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Archive for June 7th, 2007

Feds announce plan to boost desert frog

Posted by Miqe on June 7, 2007

Chiricahua leopard species threatened by drought, growth

Tucson Citizen

A frog species native to Pima County could be scratched from the federal threatened species list within about 30 years under a U.S. Fish & Wildlife Service plan announced Tuesday.

The Chiricahua leopard frog, whose habitat spans southwest New Mexico, southeast Arizona and northern Mexico, was listed in 2002 as threatened under the Endangered Species Act.

The 430-page recovery plan would rely on cooperation among governments, property owners and public land managers to help stave off the decline of the frogs, which are threatened by drought, disease and cattle ranching.

Noah Greenwald, the Center for Biological Diversity conservation biologist who wrote the petition to have the frog listed, called the plan a good start.

“I think this is one part of a larger plan that is needed to protect all of the species that rely on the rivers and streams of the Southwest,” Greenwald said.

The plan calls on ranchers and property owners to make sure the frogs can survive in backyard ponds and livestock tanks that have replaced natural habitat.

That helps, but the real issue is destruction of natural habitat that has led to declines among other species, as well, Greenwald said.

The Mexican garter snake, declining because it relies on the Chiricahua leopard frog for food, is an example, he said.

The plan calls for starting the delisting process after securing three populations of frogs in each of eight areas across Arizona and New Mexico by 2025-30.

Greenwald thinks such “museum populations” fall short of real recovery in an area where many species are at risk.

“We’re in the midst of an extinction crisis” in the Southwest, he said.

The plan calls for cooperation among U.S., tribal and Mexican governments to identify and restore habitat that has not been claimed by urbanization or other human impact.

The first five years of the recovery process are expected to cost $3.3 million, and costs beyond that would be determined later, the plan says.

Photos & images

The Chiricahua leopard frog is found in Arizona, New Mexico and Mexico.
          Additional information:
Scientific name: Rana chiricahuensis
Description: Adults range from 2 to 5 1/2 inches from nose to tail and have a distinctive pattern of raised, cream-colored spots on their thighs and greenish body color with darker spots.
Habitat: Traditionally the frogs are denizens of cienegas, ponds and streams between about 3,200-8,900 feet elevation. Their range stretches across southwest New Mexico and southeast Arizona into northeast Sonora and northwest Chihuahua in Mexico.
From Tucson Citizen

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All Caribbean frog species evolved from one South American species

Posted by Miqe on June 7, 2007

Washington, June 7: Nearly all of the 162 land breeding frog species on the Caribbean islands owe their lineage to a single frog species that rafted on a sea voyage from South America about 30-50 million years ago, a new study by Penn State University researchers has revealed.The researchers write in the June 12 issue of the Proceedings of the National Academy of Sciences, that the Central American relatives of these Caribbean frogs also arose from a single species that arrived by raft from South America.

According to Blair Hedges, evolutionary biologist and professor of biology who directed the research, “this discovery is surprising as no previous theories of how the frogs arrived had predicted a single origin for Caribbean terrestrial frogs”.

“Groups of close relatives rarely dominate the fauna of an entire continent or major geographic region. Since land connections among continents allow land-dwelling animals to disperse freely over millions of years, hence the fauna of any one continent is usually a composite of many types of animals,” said Prof. Hedges.

Previously, the anatomy of Caribbean frogs had led to theories that species in Cuba and other western-Caribbean islands were related to different mainland species than were the species on Puerto Rico and other eastern-Caribbean islands.

One prominent theory had proposed that frog species on the large islands of Cuba, Jamaica, Hispaniola, and Puerto Rico had walked there across land bridges that existed when those islands were connected in a geologic arc about 70-to-80-million years ago.

A second major theory proposed that they arrived, instead, by rafting across the Caribbean Sea after the giant asteroid impact near Cuba 65-million years ago, which is widely believed to have exterminated the dinosaurs.

Prof. Hedges said while “both theories acknowledged that the frog faunas must have arrived by rafting over water to the smaller and younger islands, the Lesser Antilles, because they never were connected by land to South America, neither of them proposed that all of the Caribbean island frog species had a single common ancestor”.

As such, “discovering a single origin for all of these species from throughout the Caribbean islands was completely unexpected,” said Prof. Hedges.

Prof. Hedges and coauthor William Duellman, a professor emeritus of the University of Kansas, were involved in much of the fieldwork.

A third co-author of the study, Penn State graduate student Matthew Heinicke, performed DNA sequencing and analyses of nearly 300 species of Caribbean, Central American and South American frogs and used three mitochondrial genes and two nuclear genes to build trees of relationships among the species and timing the divergences of the species with molecular-clock methods.

The DNA research revealed that, while many ocean dispersals might have occurred over time, only two led to the current faunas: one for the Caribbean islands and another for Central America.

“The asteroid impact generated giant waves that devastated the islands, probably eliminating any existing fauna at that time. The original frogs that successfully colonized the Caribbean islands likely hitched a ride on floating mats of vegetation called flotsam, which is the method typically used by land animals to travel across salt water,” said Prof. Hedges.

“Some rafts of flotsam, if they are washed out of rivers during storms and caught in ocean currents, can be more than a mile across and could include plants that trap fresh water and insect food for frogs. It is not likely that the frog species dispersed simply by swimming because frogs dry easily and are not very tolerant of salt water,” he said.

From DailyIndia

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