Monitoring Amphibian and Reptile Populations on
the Idaho National Laboratory: Indicators of Environmental
Health and Change
Investigators and Affiliations
Scott Cambrin, Graduate
Student, Herpetology Laboratory, Department of Biological
Sciences, Idaho State University, Pocatello, ID
Charles R. Peterson, Professor, Herpetology Laboratory,
Department of Biological Sciences, Idaho State University,
Idaho State University Graduate Student Research and Scholarship
U.S. Department of Energy Idaho Operations Office
Many amphibian and reptile species have characteristics that
make them sensitive environmental indicators. The main research
goal of this project is to provide indicators of environmental
health and change by monitoring the distribution and population
trends of amphibians and reptiles on the INL. This information
is important to the DOE for several reasons:
As an indicator of environmental health and
For management of specific populations of
requirements regarding the siting of future developments.
Providing a foundation for future research into the ecological
importance of these species.
The main objective of this project is to monitor amphibian and
reptile distribution on the INL. Specific objectives for 2006
included the following:
Continue monitoring snake and lizard populations at the three
main den complexes (Figure 9-1);
Expand monitoring program to include a 170 km driving loop to
complement the den data (Figure 9-1). This has been added
because Denim Jochimsen’s data showed that the proportion of
gopher snakes on the roads is higher than at the main den sites;
Continue to monitor breeding sites for Great Basin Spadefoot
“toads” (Spea intermontana)
Continue entering current herpetological information into a
geographic information system (GIS) database;
Provide herpetological expertise, as needed;
Provide snake safety workshops; and
Provide educational opportunities for undergraduate and
Accomplishments Through 2006
Specific accomplishments for 2006 include the following:
Continued monitoring of snake populations at
three den complexes (Cinder Butte, Crater Butte, and
Rattlesnake Cave) allowed us to increase the total number of
snakes captured by 463 snakes, 241, of which were new marks
(Figure 9-2) . Calculated
population estimates for Rattlesnake Cave (Figure 9-3).
Determined body condition for the rattlesnakes at the three
den sites for 2006 (Figure 9-4) and cumulatively for
rattlesnakes from 1994 through 2006 (Figure 9-5). Looked at the
spatial and temporal variation and estimate what environmental
characteristics might play a role in determining snake body
condition and ultimately survival.
Found 27 snakes during 10 road cruising trips.
Confirmed spadefoot toad breeding activity at the Big Lost
River sinks in 2006.
The number of marked snakes on the INL was increased to 3919
in 2006, which includes all snakes PIT-tagged since 1994 and
marking data collected at Cinder Butte from 1989 to 1994 (Table 9-1).
We found that in 2006, 54 percent of females were gravid at
Cinder Butte, 37 percent were gravid at Crater Butte, and 23
percent were gravid at Rattlesnake Cave (Figure 9-6).
Two observations of a leopard lizard (Gambelia wislizenii)
were made at Circular Butte in 2006. Western skinks (Eumeces
skiltonianus) were found in funnel traps at Rattlesnake Cave.
Sagebrush lizards (Sceloporus graciosus) were found across the
We found 20 gopher snakes (one alive), four rattlesnakes, and
three garter snakes during our road cruising surveys (Figure 9-7).
Spadefoot toad (Spea intermontana) breeding was observed in
the Big Lost River sinks, and tadpole, adults and recently
metamorphosed spadefoots were located.
Provided herpetological expertise in the form of snake safety
talks for the INL, as well as, at the Idaho Falls Earth Day
celebration and to elementary school children at different
schools and libraries. This monitoring program was the subject
of a talk at the Idaho Herpetological Society in November 2006.
Through the continuation of Scott Cambrin’s Masters Degree
research he has also started to look at some of the factors
affecting body condition and pregnancy rates. He found there was
a positive correlation with yearly precipitation and body
condition with an R2 value of 0.37 and a p-value of 0.035
(Figure 9-8). He also found a significant relationship between
body condition and percent gravid females with an R2 value of
0.36 and a p-value of 0.039 (Figure 9-9).
Plans for Continuation
A M.S. thesis is expected to be completed in 2007 by S. Cambrin
based on this work. Monitoring herpetofauna is one part of the
wildlife monitoring task in the ESER program and is expected to