Monitoring amphibians in Great Smoky Mountains National Park

Abstract

Amphibian species have inexplicably declined or disappeared in many regions of the world, and in some instances, serious malformations have been observed. In the United States, amphibian declines frequently have occurred even in protected areas. Causes for the declines and malformations probably are varied and may not even be related. The seemingly sudden declines in widely separated areas, however, suggests a need to monitor amphibian populations as well as identify the causes when declines or malformations are discovered. In 2000, the President of the United States and Congress directed Department of the Interior (DOI) agencies to develop a plan to monitor the trends in amphibian populations on DOI lands and to conduct causes of declines. The DOI has stewardship responsibilities over vast land holdings in the United States, much of it occupied by, or potential habitat for, amphibians. The U.S. Geological Survey (USGS) was given lead responsibility for planning and organizing this program, named the Amphibian Research and Monitoring Initiative (ARMI). Authorization carried the mandate to set up a national amphibian monitoring program on Federal lands, to develop the sampling techniques and biometrical analyses necessary to determine status and trends, and to identify possible causes of amphibian declines and malformations. The biological importance of Great Smoky Mountains National Park has been recognized by its designation as an International Biosphere Reserve. As such, it is clearly the leading region of significance for amphibian research. Although no other region shares the wealth of amphibians as found in the Great Smokies (31 species of salamanders, and 13 of frogs), the entire southern and mid-section of the Appalachian Mountain chain is characterized by a high diversity of amphibians, and inventories and monitoring protocols developed in the Smokies likely will be applicable to other Appalachian National Park Service properties. From 1998 to 2001, USGS biologists carried out a pilot inventory and monitoring research project in Great Smoky Mountains National Park. A variety of inventory, sampling, and monitoring techniques were employed and tested. These included wide-scale visual encounter surveys of amphibians at terrestrial and aquatic sites, intensive monitoring of selected plots, randomly placed small-grid plot sampling, litterbag sampling in streams, monitoring nesting females of selected species, call surveys, and monitoring specialized habitats, such as caves. Coupled with information derived from amphibian surveys on Federal lands using various other techniques (automated frog call data loggers, PVC pipes, drift fences, terrestrial and aquatic traps), an amphibian monitoring program was designed to best meet the needs of biologists and natural resource managers after taking into consideration the logistics, terrain, and life histories of the species found within Great Smoky Mountains National Park. This report provides an overview of the Park’s amphibians, the factors affecting their distribution, a review of important areas of biodiversity, and a summary of amphibian life history in the Southern Appalachians. In addition, survey techniques are described as well as examples of how the techniques are set up, a critique of what the results tell the observer, and a discussion of the limitations of the techniques and the data. The report reviews considerations for site selection, outlines steps for biosecurity and for processing diseased or dying animals, and provides resource managers with a decision tree on how to monitor the Park’s amphibians based on different levels of available resources. It concludes with an extensive list of references for inventorying and monitoring amphibians. USGS and Great Smoky Mountains National Park biologists need to establish cooperative efforts and training to ensure that congressionally mandated amphibian surveys are performed in a statistically rigorous and biologically meaningful manner, and that amphibian populations on Federal lands are monitored to ensure their long-term survival. The research detailed in this report will aid these cooperative efforts.