11/18/14-University of Missouri-Columbia
In
the 1970s, ecologists published results from one of the first
whole-forest ecosystem studies ever conducted in Hubbard Brook, New
Hampshire. In the paper, scientists reported that salamanders represent
one of the largest sources of biomass, or food, of all vertebrates in
the forest landscape. Now, using new sampling and statistical techniques
not available during the past study, researchers at the University of
Missouri have estimated that the population of salamanders in forested
regions of the Missouri Ozarks are 2-4 times higher than originally
thought, and in other regions of the eastern U.S. may be on average 10
times higher. Scientists believe that acknowledging salamanders as one
of the main food sources in forest ecosystems could help drive
conservation efforts and forest management.
"Our
lab works to identify salamanders as an influential part of the forest
ecosystem and food chain," said Ray Semlitsch, Curators Professor of
Biological Sciences in the College of Arts and Science at MU. "Using the
latest research methods, we calculated the population size of Southern
Redback Salamanders in Ozark Forests and their value as a food source.
We found that 1.88 billion salamanders inhabit one district of the Mark
Twain National Forest alone, which is roughly 1,400 metric tons of
biomass. For comparison, that's equivalent to the biomass found in most
whitetail deer in that region!"
There
are two methods for estimating abundance. One is to simply count
salamanders and plot the numbers on a grid representing the forest
landscape. That is how the estimates were calculated in the 1970s.
However, Semlitsch's group, armed with the knowledge that the majority
of salamanders are underground at any given time, captured animals on
the surface during intensive repeated surveys over two years and used
statistical modeling to produce a more thorough accounting of variation
in salamander population density.
"Our
abundance models also take into account environmental factors,"
Semlitsch said. "Factors such as date of collection, time since last
rainfall, slope of the terrain and forest canopy cover are plugged into
the model to help predict variation in the surface population over time;
that's what makes our model so powerful. The hidden biodiversity of
amphibians is something we don't generally consider; we forget that
salamanders are nocturnal and mostly unobserved. Therefore, I think most
will be amazed at the quantities of food out there that we just don't
see."
Semlitsch
believes that future research should consider the importance of
amphibians to ecosystem processes such as soil enrichment. Future forest
management techniques and protection of salamanders are important to
healthy forest ecosystems and should be considered in all forest
management decisions, Semlitsch said.
Story Source:
Journal Reference:
- R.D.
Semlitsch, K.M. O’Donnell, F.R. Thompson. Abundance, biomass
production, nutrient content, and the possible role of terrestrial
salamanders in Missouri Ozark forest ecosystems. Canadian Journal of
Zoology, 2014; 997 DOI: 10.1139/cjz-2014-0141
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