Elusive salamanders have role in developing new sampling models

06/01/05

OAK RIDGE, Tenn., June 1, 2005 Rare salamanders at a Georgia military base are the guinea pigs for Oak Ridge National Laboratory researchers whose goal is to develop methods to better determine whether a species has vanished.

After not finding any flatwoods salamanders since 2001, Fort Stewart biologists were a bit concerned and were looking for a better survey method, said Mark Bevelhimer, an aquatic ecologist and member of ORNL's Environmental Sciences Division. A Strategic Environmental Research and Development Program project is helping in that area and addressing even greater challenges.

"Just because you don't see any of the specific species you are looking for doesn't mean they aren't there," Bevelhimer said. "So for us, our task is to develop a method to make field sampling techniques more accurate and efficient. With that information, we can improve our models, and we should be able to do a better job of predicting the type and location of suitable habitats plus minimize unnecessary and time-consuming sampling."

Of more than 1,000 seasonal ponds at the 280,000-acre military facility in southeastern Georgia, 483 have been identified as potential candidates to support this particular salamander, technically known as Ambystoma cingulatum. Until April 21, however, none had been found over a stretch that spanned four years. Researchers noted that this was not totally unexpected because of a 100-year drought event that dried ponds and halted reproduction from 1999 through 2002. Since the first salamander was found six weeks ago, 36 more have been found in one pond, but none in 11 others that have supported them in the past.

In the United States, flatwoods salamanders are found only in Florida, South Carolina and Georgia. The adults lay their eggs in wetland depressions in the late fall. With winter rains, the ponds rise and the eggs hatch in December, January and February. Larval development lasts through May. The larvae then undergo metamorphosis and leave the ponds as terrestrial juveniles. Juvenile and adult salamanders may move 400 or more yards from ponds and burrow in old crayfish holes and other crevices in soggy pine flatwoods.

This research is important to the military because better information about the presence or absence of salamanders can help installation natural resource managers apply effective conservation strategies for this species. Helping provide research tools that support conservation is one of the missions of the SERDP.

The three-year SERDP project, which began in January, takes advantage of some of the Department of Energy laboratory's extensive capabilities. In addition to Bevelhimer's contributions in the area of quantitative ecology, other ORNL researchers involved in the project are Neil Giffen, a wildlife biologist, and Bill Hargrove, a habitat modeler. Fort Stewart herpetologist Dirk Stevenson is also a key player in the project and is responsible for monitoring the rare reptile and amphibian populations on base.

Kara Ravenscroft, the project's technician, actually found the first salamander, which she trapped. In subsequent sampling she has extended the date of recorded residence by larval flatwoods salamanders in Fort Stewart ponds by two to three weeks, which is well beyond the period when experts thought they normally leave ponds.

One of the project tasks consists of field experimentation to compare the larval capture efficiency of methods in use at Fort Stewart with methods used by other researchers for other salamander populations and with methods being developed during this project. These studies will be performed in coordination with the existing program, which includes sampling suspect ponds over the next six to 12 years.

Researchers also will compare sampling effectiveness of the different methods, looking closely at cost, and also use several sites to calculate the best approach to estimate juvenile abundance. Meanwhile, Hargrove and local biologists will gather physical data about the ponds and their watersheds combined with the presence or absence of salamanders to develop models to identify ponds most likely to support reproduction of the flatwoods salamander.

The habitat modeling takes into account numerous environmental and other variables and will be used to identify the relative importance of different factors for predicting the presence of salamanders. This process will provide valuable information for the management of flatwoods salamander habitat.

A final component of the project is technology transfer, as this research is expected to produce results and a tool useful to scientists and others working with rare species.

"In the third year of the project, we will be testing our model at Eglin Air Force Base in Florida, where flatwoods salamanders are also found," Bevelhimer said. "We expect that the methods we develop will be useful in flatwoods salamander conservation throughout the Southeast. More importantly, we are hopeful that these methods can be applied to monitoring efforts for a variety of rare species as part of the ongoing challenge faced by natural resource managers to balance resource use and resource preservation."

Source: Eurekalert & others

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