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Unfortunately, many of our vernal ponds in SW Nova Scotia are now too acidi=
c for amphibian eggs, so perhaps we should be throwing a piece of limestone=
in at the same time.
In a 1999 essay "Pickled Eggs and Frogs' Legs", John Brownlie noted the neg=
ative effects of acid rain on amphibians in SW Nova Scotia, and that adults=
will keep laying eggs even in waters that are acid enough to pickle the eg=
gs. He was hopeful that acidification would be reversed by 2020, by which t=
ime the adults would have passed on but then "there will still be people li=
ke me around who love frogs and salamanders; who like to hear them singing =
in the spring and who observe their mating rituals in breeding ponds. These=
people will re-introduce amphibians to ponds and lakes from which they hav=
e disappeared."
As now well documented, SW Nova Scotia is NOT seeing the reversal in acidif=
ication accruing from emission controls seen in other regions because our s=
oils/rocks have some of the lowest weathering rates (and hence lowest capac=
ity to replace calcium and other basic cations) amongst soils of Europe and=
eastern North America, a situation that is only worsened by clearcutting.
So my thought is that we should be both transferring eggs and throwing a pi=
ece of limestone into these ponds to keep the populations going for a futur=
e age. A good research project for sure, but in the absence of that under t=
he present regimes, perhaps some guerilla action to save our amphibians?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
* Donna Crossland<https://ca-mg6.mail.yahoo.com/neo/launch?.rand=3Ddml2=
ots1jou79#>
* Today at 10:49 AM
To
* naturens@chebucto.ns.ca
Hello Fred: What do you think of possibly transferring some to those
otherwise "doomed" wood frog egg masses to the more traditional ponds
located nearby, where wood frogs are traditionally known to frequent? I
know that we humans have a tendency to "play God" with wildlife, but this
would seem like a fairly innocuous thing to do with perhaps very positive
outcomes. With many wetland sites already dealing with external stressors
caused directly/indirectly by humans, is it possible that we could help out
a little here (if so inclined)?
This question may be more philosophical than natural history-based.
Donna Crossland
-----Original Message-----
From: naturens-owner@chebucto.ns.ca<mailto:naturens-owner@chebucto.ns.ca> [=
mailto:naturens-owner@chebucto.ns.ca<mailto:naturens-owner@chebucto.ns.ca>]
On Behalf Of Fred Schueler
Sent: April-20-14 8:50 AM
To: naturens@chebucto.ns.ca<mailto:naturens@chebucto.ns.ca>
Cc: Owen Clarkin; Phil Chadwick
Subject: Re: [NatureNS] wood frog eggs
Quoting nancy dowd <nancypdowd@gmail.com<mailto:nancypdowd@gmail.com>>:
> On the Big Lots Rd, Northwest, Lun Co, there was a steady quacking of
> Wood Frogs late yesterday afternoon. Their dark egg masses were
> everywhere along the dirt road- in ditches, large and small puddles
> and even in shallow tire ruts. The latter two locations are quite a
> gamble unless we continue to have wet weather. Or is it possible for
> Wood Frog eggs to tolerate some degree of drying out?
* no, they just lay in the "best available site" as judged by them at the
time (they're never more than 10cm above the ground). This spring we've got
a chorus here that usually breeds in a nice Red Maple swamp, but this year,
with an unusual thawing process, they're calling from a flooded area in a
harvested Soybean field, which will almost certainly dry up long before the
tadpoles are ready to transform.
We call what you describe "rut breeding" and in Ontario it seems to be
characteristic of El Nino springs, which seem to have early warm spells
without much rain, so that little rut-like waterbodies are thawed before th=
e
breeding ponds.
see - http://fragileinheritance.org/documents/RESULTS_Cochrane.pdf - "In
1983, the first El Nino spring that we were aware of as such, cold and
warmth alternated so abruptly that eggs were laid in flooded tire ruts all
across Ontario, from the Niagara Peninsula to our study site at Long Lake,
south of Cochrane (48.91606N 80.97202W; see Weaving a fabric of sound, FWS,
2001. Trail and Landscape 35(1):8-11). Again in the El Nino spring of 2002,
on the James Bay Expedition, we found that 'Most auditory records from 14-1=
6
May around Cochrane, and at Moosonee, were index 3 choruses, but these were
not actively breeding congresses, as the choruses could not be approached,
and no concentrations of egg masses were laid at those chorus sites that
could be visited during daylight. Scattered egg masses were laid in the rut=
s
along the track at Long Lake.'
"In 2010, temperatures in the first days of April reached 27?C around
Cochrane, well before lakes, or ponds the size of those where Wood Frogs
breed, were thawed. We presume that this led the frogs to move overland and
lay eggs in tiny bodies of water such as tire ruts.
Subsequent cold temperatures froze these eggs, which were in a granular
tapioca-like condition, bright green with colonizing algae, when we surveye=
d
them. Crystal marks on the bottoms of puddles in the road at Long Lake
suggested that small waterbodies had frozen to a depth of 10cm. A few
eggmasses, that presumably had been laid subsequently, had hatched, or
developed towards hatching, though without a sufficient volume of water in
the ruts there couldn't be much expectation that they'd persist through the
summer to transformation.
fred.
------------------------------------------------------------
Frederick W. Schueler & Aleta Karstad Bishops Mills Natural
History Centre - http://pinicola.ca/bmnhc.htm Mudpuppy Night in Oxford Mill=
s
- http://pinicola.ca/mudpup1.htm Daily Paintings -
http://karstaddailypaintings.blogspot.com/
South Nation Basin Art & Science Book
http://pinicola.ca/books/SNR_book.htm
RR#2 Bishops Mills, Ontario, Canada K0G 1T0
on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
(613)258-3107 <bckcdb at istar.ca> http://pinicola.ca/
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