RE: [vernalpool] cause of spotted salamander mass mortality?

I attended a presentation called A Salted Salamander: Impacts of Road Runoff on Amphibians by Steven Brady of Yale University School of Forestry last year. The website has a link to an article which appeared in Science Daily. His email is: steven.brady@yale.edu

http://environment.yale.edu/skelly/steveb.html

Sophie Zyla

--- On Mon, 5/7/12, Brett Amy Thelen <thelen@harriscenter.org> wrote:

From: Brett Amy Thelen <thelen@harriscenter.org>
Subject: RE: [vernalpool] cause of spotted salamander mass mortality?
To: vernalpool@yahoogroups.com
Date: Monday, May 7, 2012, 4:43 PM

Hello again everyone --

Thanks to everyone for your thoughts! A few follow-up pieces of
information:

(1) The salamanders were found near the road (not in the wetland), although
I haven't yet been able to find out anything about their condition (i.e.,
were they desiccated, as you might expect with calcium chloride?) or the
exact date they were found.

(2) We've had some pretty cold nights in the last few weeks (temperatures in
the teens & 20s) but our pools haven't held ice for quite some time.
However, if the mortality event actually happened in March or early April,
and the news only just now found its way to me, Bryan's cold-snap theory
could make sense for this site.

(3) Matt Burne suggested I contact a faculty member at Plymouth State who
had done her master's thesis on salt impacts to breeding pools. She did not
have much information on calcium chloride or adult salamander mortality, as
she had worked primarily with embryos, but she did send along one citation
that made note of the potential impacts of roadside contaminants:

Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors
that may present a risk to population viability and accounts on the
identification, distribution, taxonomy, habitat use, natural history, and
the status and conservation of individual species. Report to USFS Region 1,
Order Number 43-0343-0-0224. University of Montana, Wildlife Biology
Program. Missoula, Montana. 161 pp.

This is the specific paragraph of note:

"Contaminant runoff from roads or campground surfaces may also affect
amphibians. Maintenance of gravel road surfaces with calcium or magnesium
chloride or oils in order to control airborne dust and prolong the life of
the road surface may present a serious biohazard. Calcium chloride has been
associated with mass mortalities of migrating salamanders apparently as a
result of desiccation caused by the chemical (deMaynadier and Hunter 1995).
Petroleum products may also contaminate aquatic habitats next to roadways or
may be directly introduced from motorized watercraft. Mahaney (1994)
examined the effects of crankcase oil on tadpoles of the green treefrog
(Hyla cinerea). Concentrations of 100 mg/L inhibited tadpole growth and
prevented metamorphosis. Finally, although leaded fuels are no longer a
concern, Birdsall et al.'s (1986) finding that lead concentrations in frog
tadpoles living in roadside ponds and ditches were correlated with daily
traffic volumes in Maryland and Virginia demonstrates how contaminant levels
are likely to be correlated with traffic volume."

If I get any more information, I'll let you all know!

Best,
Brett

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