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The Need for Long-Term Monitoring
In recent decades, biologists have documented worldwide declines in
amphibian populations. Several species are now extinct, and other
once-thriving populations have diminished greatly in numbers.
Amphibian deformities also appear to be on the rise. Possible causes of
declines and deformities include habitat degradation and loss,
introduction of pathogens, fish and other animals in to ecosystems,
thinning of the ozone layer and increased exposure to ultraviolet
radiation, environmental contaminants, and commercial exploitation
(Beebee 1996; Mitchell 2000).
The problem for scientists and citizens concerned about amphibians is
that we lack the long-term data sets necessary for realistic
evaluations of population trends.
Natural fluctuations in amphibian population numbers from year to year
make it difficult to determine overall trends in population growth and
decline. Are populations in a given area declining, stable, or
increasing? Are populations declining in some areas and not in others?
Answers to such questions require information from numerous places over
many years where scientists are using the same methodologies (Mitchell,
2000). An accurate assessment of the distribution and abundance of
amphibians is a first step towards understanding the causes and extent
of amphibian decline.
Monitoring Amphibians on the Palouse (MAP) is one of a growing number
of long-term monitoring projects nationwide that rely on data gathered
by citizen volunteers to add to our understanding of amphibian
population declines. The southern portion of Latah County presents a
unique opportunity to conduct a long-term monitoring project for
several reasons, as listed below.
- Northern Idaho boasts a rich amphibian diversity, yet the ranges of
the species present have just begun to be documented. A detailed
assessment of the amphibian population of 37 artificial ponds in Latah
County was conducted in 1996-97 by University of Idaho graduate student
Ryan Monello. Four of the ponds in his study had been monitored for
amphibian presence in 1976-77. These studies provide excellent baseline
data about Palouse amphibian populations.
- Two amphibian species present here, the Columbia spotted frog, Rana
luteiventris, and the Western toad, Bufo boreas, have declined
significantly in adjacent portions of their range, but have not been
noted to be in a state of decline in the Palouse (Monello, 1998).
- Bullfrogs, an introduced species, and roughskin newts, a possible
introduced species, are present in several of the 37 ponds in Monello’s
study, and their movement to new ponds can be tracked as part of the
monitoring project.
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