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Hi Fred & All, June 30, 2014
Unless someone actually recorded the number of turtles removed or at =
least a respectable sample of removal there is no valid reason to assume =
removal to be the cause of decrease. Or even a valid reason to assume =
that a significant number were removed.=20
Other changes might have taken place concurrently. The =
characteristics of that water, if sampled, might provide a clue. BTW =
water low in alkalinity is very poorly buffered so if site also had high =
pH and low alkalinity then it would be unusually vulnerable to =
acidification by acid rain.=20
Removing 15% of turtles from a watershed year after year until they =
were gone is not realistic. How does one proceed to remove that last few =
percent ? Capturing a constant percentage of the original population =
year after year would require greatly enhanced collecting effort with =
time. A constant decrease over time suggests a population that, due to =
some degradation of the environment such as acid rain, was not =
reproducing. A reproducing population should have compensated for =
removal (a type of predation) by increasing egg count per female.
Some years ago I was on a Lep site and one long post related how =
collecting had been 'conclusively' tied to extirpation of a rare Lep. =
Someone found a glassine envelope, no rare Lep on site and jumped to a =
conclusion which was soon spread widely as documented fact. Fortunately =
someone had the good sense to check across the road where an artillery =
range tended to start fires and retain the open habitat and Carex that =
this Lep needed. The Lep had just moved where it could continue to have =
access to this Carex.=20
Yt, DW
=20
=20
----- Original Message -----=20
From: "Fred Schueler" <bckcdb@istar.ca>
To: <naturens@chebucto.ns.ca>; "John Gilhen" <GILHENJA@gov.ns.ca>; =
"Andrew Hebda" <HEBDAAJ@gov.ns.ca>
Sent: Monday, June 30, 2014 8:07 PM
Subject: Re: [NatureNS] Wood Turtle: long
> On 6/30/2014 6:13 PM, David & Alison Webster wrote:
>=20
>> I noticed on a post to naturens recently that (from the NS =
Museum
>> of NH site)--
>> "It may seem harmless to keep a turtle as a pet for a while, but this =
is
>> not a good idea. Two of the province's four turtle species are =
already
>> at risk in Nova Scotia. It is likely that removal of turtles by =
people
>> is part of the reason, for Wood Turtles."
>> I expect this supposition rests in part on your 1984
>> statement (Amphibians and Reptiles of Nova Scotia p. 148) that--
>> "Another problem facing the Wood Turtle is the removal of many
>> individuals from their habitat by people while on fishing trips or
>> camping trips" which are then subsequently "released in the woods =
many
>> kilometers from its natural habitat."
>> Perhaps you can provide some details of the observations on =
which
>> your above statement was based.
>=20
> * the story is told, though I don't have the reference at hand, of a=20
> municipal drinking water-shed reserve in Connecticut, where, in the=20
> glorious germ-phobia of the 1920s, all random human access was=20
> prohibited. A student studied the Wood Turtles there, and found a=20
> certain population.
>=20
> Then in the we'd-never-think-of-pooping-in-the-woods of the 1980s, =
that=20
> reserve was opened to hiking and biking and all, without otherwise=20
> changing the habitat, and the Wood Turtles declined at a rate of =
15%/yr,=20
> until they were gone.
>=20
> I believe there's numerous places where similar declines due to casual =
> pet-taking have been observed, though this case would seem to be=20
> exceptionally well documented.
>=20
> fred.
> ------------------------------------------------------------
> Frederick W. Schueler & Aleta Karstad
> Daily Paintings - http://karstaddailypaintings.blogspot.com/
> Vulnerable Watersheds - http://vulnerablewaters.blogspot.ca/
> study our books - http://pinicola.ca/books/index.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/
> ------------------------------------------------------------
>=20
>=20
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2014.0.4714 / Virus Database: 3986/7771 - Release Date: =
06/30/14
>
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<DIV>Hi Fred & All, =
=20
=
=20
June 30, 2014</DIV>
<DIV> Unless someone actually recorded the number of =
turtles=20
removed or at least a respectable sample of removal there is no valid =
reason to=20
assume removal to be the cause of decrease. Or even a valid reason to =
assume=20
that a significant number were removed. </DIV>
<DIV> Other changes might have taken place =
concurrently.=20
The characteristics of that water, if sampled, might provide a clue. BTW =
water=20
low in alkalinity is very poorly buffered so if site also had high =
pH and=20
low alkalinity then it would be unusually vulnerable to =
acidification=20
by acid rain. </DIV>
<DIV> Removing 15% of turtles from a watershed year =
after year=20
until they were gone is not realistic. How does one proceed to remove =
that last=20
few percent ? Capturing a constant percentage of the original=20
population year after year would require greatly enhanced =
collecting effort=20
with time. A constant decrease over time suggests a population that, due =
to some=20
degradation of the environment such as acid rain, was not =
reproducing. A=20
reproducing population should have compensated for removal (a type of =
predation)=20
by increasing egg count per female.</DIV>
<DIV> Some years ago I was on a Lep site and one long =
post=20
related how collecting had been 'conclusively' tied to extirpation of a =
rare=20
Lep.