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The Rainbow Bay Long-term Study

David Scott, Brian Metts, and Stacey Lance


Many years have passed since schoolchildren first discovered hundreds of malformed frogs in a Minnesota farm pond. Twenty years have elapsed since scientists initiated earnest discussions concerning "global amphibian decline." Still, many questions addressing the decline and disappearance of frogs, toads, and salamanders remain unanswered. Which species? How many individuals? Where? And why?

All these questions are the focus of global, ongoing research efforts. Researchers are investigating the myriad possible causes of decline: wetland and terrestrial habitat loss, chytrid fungus, climate change, ozone depletion, aquatic contaminants, endocrine disruption, introduced predators, parasites, acid rain, and more. Regardless of the research topic, in virtually every scientific discussion of the amphibian crisis, one research project is mentioned as a model for acquiring the long-term baseline data needed to understand amphibian population fluctuations. That study is the 34-year Rainbow Bay Monitoring Project at the Savannah River Site (SRS).

Rainbow Bay is a 2.4-acre isolated seasonal wetland in the center of the SRS. Sampling of the amphibian and reptile communities that use the wetland, as well as the surrounding 85-acre terrestrial habitat, began in September 1978. Animal populations have been censused daily since initiation of the study, making this project the longest running community study of its kind in the world. More than 60 scientific articles on the fauna of this wetland have been published, making it one of the best-studied habitats of its type. Although this study was initiated by the Department of Energy to assess potential ecological impacts of construction of a high-level waste vitrification facility (the Defense Waste Processing Facility), it has achieved that monitoring goal and much more. Daily records of the amphibians and reptiles of Rainbow Bay have provided an extensive database regarding seasonal and annual variation in amphibian numbers at a site that remains relatively unimpacted by human activities. SREL's data have become critically important to the scientific and conservation communities in light of concerns about declining amphibian populations worldwide and potential effects of climate change.

The long-term data from Rainbow Bay allow analyses that cannot be conducted on short-term data – these analyses include population trends, environmental determinants of changes in community structure, determinants of survivorship, and potential consequences of climate change.

ACKNOWLEDGEMENTS:We would like to numerous people for their help in starting the Rainbow Bay study and running drift fences in the early years and beyond, including: Jan Caldwell, Brian Crawford, Anne Dancewicz –Helmers, Matt Erickson, Ruth Estes, Whit Gibbons, Judy Greene, Gary Moran, Joe Pechmann, Rich Seigel, Ray Semlitsch, and Laurie Vitt. Numerous students also assisted in the field. Rainbow Bay currently serves as a reference site for several studies concerned with potential effects of contaminants on amphibians. Funding for the project is provided by the National Nuclear Security Administration (NNSA) of DOE, and the Area Completion Projects group of Savannah River Nuclear Solutions (SRNS). Work has also been supported by the Department of Energy under Award Number DE-FC09-07SR22506 to the University of Georgia Research Foundation.

aerial of Rainbow Bay

Rainbow Bay

figure: changes in community structure 1979-2005figure: shift in breeding date 1979-2005

Some residents of Rainbow Bay:

Tiger Salamander (Ambystoma tigrinum)

Marbled Salamander (Ambystoma opacum)

Mole Salamander (Ambystoma talpoideum)


Larval Salamanders

Eastern Spadefoot Toad (Scaphiopus holbrookii)

Ornate Chorus Frog (Pseudacris ornata)


Selected Reprints:

  • Scott, DE, Komoroski MJ, Croshaw DA, and Dixon PM. 2013. Terrestrial distribution of pond-breeding salamanders around an isolated wetland. Ecology 94:2537-2546. (pdf)
  • Todd, BT, DE Scott, JHK Pechmann, and JW Gibbons. 2011. Climate change correlates with rapid delays and advancements in reproductive timing in an amphibian community. Proceedings of the Royal Society B 278:2191-2197. (pdf)
  • Scott, DE. 2008. Marbled salamander, Ambystoma opacum. Pages 139-141 in: Jensen, John, Carlos Camp, Whit Gibbons, and Matt Elliott (eds.), Amphibians and Reptiles of Georgia. University of Georgia Press, Athens, GA.
  • Scott, DE, ED Casey, MF Donovan, and TK Lynch. 2007. Amphibian lipid levels at metamorphosis correlate to post-metamorphic terrestrial survival. Oecologia 153:521-532. (pdf)
  • Taylor, B. E., D. E. Scott, and J. W. Gibbons. 2006. Catastrophic reproductive failure, terrestrial survival, and persistence of the marbled salamander. Conservation Biology 20:792-801. (pdf)
  • Scott, DE. 2005. Ambystoma opacum, Marbled salamander. Pp. 627-632 in: Amphibian Declines: the Conservation Status of United States Species. M. J. Lannoo (ed.), University of California Press, Berkeley, CA. (pdf)
  • Daszak, P., D. E. Scott, A. M. Kilpatrick, C. Faggioni, J. W. Gibbons, and D. Porter. 2005. Amphibian population declines at the Savannah River Site are linked to hydroperiod, not chytridiomycosis. Ecology 86:3232-3237. (pdf)
  • Pechmann, JHK, RA Estes, DE Scott, and JW Gibbons. 2001. Amphibian colonization and use of ponds created for trial mitigation of wetland loss. Wetlands 21:93-111. (pdf)
  • Semlitsch, R. D., D. E. Scott, J. H. K. Pechmann, and J. W. Gibbons. 1996. Structure and dynamics of an amphibian community: evidence from a 16-yr study of a natural pond. Pages 217-248 In "Long-term Studies of Vertebrate Communities." M. L. Cody and J. D. Smallwood (eds.). Academic Press, New York. (pdf)
  • Semlitsch, R. D., D. E. Scott, J. H. K. Pechmann, and J. W. Gibbons. 1993. Phenotypic variation in the arrival time of breeding salamanders: individual repeatability and environmental influences. Journal of Animal Ecology 62:334-340. (pdf)
  • Pechmann, J.H.K., D. E. Scott, R. D. Semlitsch, J. P. Caldwell, L. J. Vitt, and J. W. Gibbons. 1991. Declining amphibian populations: the problem of separating human impacts from natural fluctuations. Science 253:892-895. (pdf)
  • Pechmann, J. H. K., D. E. Scott, R. D. Semlitsch, and J. W. Gibbons. 1989. Influence of wetland hydroperiod on diversity and abundance of metamorphosing juvenile amphibians. Wetlands Ecology and Management 1:1-9. (pdf)
  • Semlitsch, R. D., D. E. Scott, and J. H. K. Pechmann. 1988. Time and size at metamorphosis related to adult fitness in Ambystoma talpoideum. Ecology 69:184-192. (pdf)
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