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

Hey Brett,

If the salamanders were found by the roadside (as opposed to along the edge
of the wetland) the quick freeze idea may be somewhat less likely. You
might wish to get in touch with Mac (Malcolm) Hunter at U Maine Orono to
see what he has to say about the reference to CaCl2 related mortality.

If the calcium chloride is used to control dust and it was responsible for
the mortality it brings up an interesting weird weather link as it would be
highly unusual - I'm guessing - to worry about dust in NH in April (usually
mud season!) but no so this year. To get more info. on this theory, I'd
suggested that you ask the town (if you haven't already done so) if they
applied any dessicant to the road around migration time this spring. It's
unlikely that an old application (like from the winter or previous fall)
would be an issue as the salt would have long before mostly washed away and
run off.
Good luck with the case!
Bryan

On Mon, May 7, 2012 at 4:43 PM, Brett Amy Thelen <thelen@harriscenter.org>wrote:

> **
>
>
> 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
>
>
> [Non-text portions of this message have been removed]
>
>
>


[Non-text portions of this message have been removed]



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