Eric,
Dr. Peck has already said it is unlikely that rufa Red Knots will be
extinct by 2010, and claims that their paper (Baker et al., 2004) never
explicitly said that they would be. In a recent private communication to me
he has also stated that the model using 1998-2001 data was only a snapshot
during that time period only and that they never suggested anything more in
the paper. Contrast this to statements that you and others unfortunately
made saying that "absent bold action, extinction by 2010 is certain". The
model is in the process of failing, as the rate of decline has slowed and
the population is levelling out. As far as I'm concerned, extinction by or
about 2010 was never a reasonable possibility. Dr. Peck concurs that the
information from the paper was misused and that their paper was misquoted by
the various well-meaning conservation organizations including NJ Audubon,
for the purpose of garnering support for the moratorium. Will NJ Audubon
now stop using the 'extinction by or about 2010' line?
I do wish you and everyone involved every success in the necessary
conservation measures needed to restore the migratory populations of knots
and other shorebirds in Delaware Bay,
Sincerely,
Rick Heil
Richard S. Heil
S. Peabody, MA
[log in to unmask]
----- Original Message -----
From: "Eric Stiles" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, May 31, 2007 6:31 PM
Subject: [SHOREBIRDS] Red Knot Extinction Question Redux
> I have been copied on a posting made by Mr. Heil dated May 25, 2007 which
> cast aspersions on the Baker et al (2004) study. The study includes
models
> of population changes for the Red Knot rufa subspecies. Per Dr. Peck's
> well-written and appropriate response, NJ Audubon and its many
conservation
> partners who are working to protect the Delaware Bay shorebird stopover,
> correctly reference the Baker et al study to substantiate the high risk of
> extinction. It is truthful to state that population models for the Red
Knot
> rufa subspecies demonstrate that the population could be at or near
> extinction circa 2010. No one pretends population models are a crystal
> ball, but it provides a useful temporal context in which to categorize
> probability of extinction. To date, I have not read or seen any
> publications or presentations claiming that the Red Knot rufa subspecies
is
> anything other than highly imperiled.
>
> According to leading scientists from the Wader Study Group, prior to the
> overharvest of horseshoe crabs the Delaware Bay was one of the top four
most
> important stopover locations in the world. Both the Baker et al (2004)
and
> Morrison et al (2004) articles document the rapid decline of Red Knots on
> the Delaware Bay and discuss a causal link of the decline to the
overharvest
> of horseshoe crabs. Furthmore, as Dr. Peck wrote, other species such as
the
> Ruddy Turnstones, Sanderlings and Semipalmated Sandpipers are also
> exhibiting declines in weight gain rates and population.
>
> While Mr. Heil may doggedly attack the strong science of Baker and his
> co-authors, I would rather welcome all to join us in restoring the
Delaware
> Bay shorebird stopover site to its former resplendent, intact condition
> hosting nearly 1 million individuals from 9 shorebird species.
>
> Below are excerpts from the two cited studies which I feel help establish
a
> baseline for discussion:
>
> 1. In a recent publication in the Proceedings of the Royal Society of
London
> (2004), Dr. Baker et al. made the following findings and conclusion, "From
> 1997-2002 known survivors in Delaware Bay were heavier at initial capture
> than birds never seen again, annual survival of adults decreased by 37%
> between May 2000 and May 2001, and the number of second year birds in
> wintering flocks declined 47%... Population size in Tierra del Fuego
> declined alarmingly from 53,000 to 27,000 in 2000-2002, seriously
> threatening the viability of this subspecies. Demographic modelling
predicts
> imminent endangerment and an increased risk of extinction of the
subspecies
> without urgent risk-averse management."
>
> 2. Similarly, Dr. Morrison et al. (2004) reported in Condor that "Surveys
of
> the North American race of the Red Knot (Calidris canutus rufa) on its
main
> wintering areas on the coasts of Patagonia and Tierra del Fuego (Argentina
> and Chile) showed a dramatic decline in the wintering population: totals
in
> 2003 were about 30 000 compared to 67 500 in the mid-1980s. Numbers at
the
> principal wintering site, Bahia Lomas, fell by approximately 50%, from 45
> 300 in 2000 to 22 000-25 000 in 2002-2003. Numbers at peripheral sites on
> the coast of Patagonia declined dramatically, decreasing 98% compared to
> numbers in the mid-1980s. Possible reasons for the declines are discussed.
> Banding studies in Delaware Bay have shown that in recent years an
> increasing proportion of Red Knots is unable to gain sufficient weight for
> migration to the breeding grounds. This is likely due to reductions in
> their main food resource, eggs of the horseshoe crab Limulus polyphemus.
> The resulting increase in mortality could account for the magnitude and
> severity of the declines we observed."
>
> Citations
>
> Baker, Allan J., Patricia M. Gonzalez, Theunis Piersma, Lawrence J. Niles,
> Ines de Lima Serrano do
>
> Nascimento, Phillip W. Atkinson, Nigel A. Clark, Clive D.T. Minton, Mark
K.
> Peck, and Geert
>
> Aarts. 2004. Rapid population declines in red knots: fitness consequences
of
> decreased refueling
>
> rates and late arrival in Delaware Bay. Proc. R. Soc. Lond. B (2004) 271,
> 875-882
>
> Morrison, R.I. Guy, P. Kenyon Ross and Lawrence J. Niles. 2005. Declines
in
> wintering populations
>
> of Red Knots in Southern America. The Condor. 106:60-70.
>
> Sincerely,
> Eric Stiles, Vice President for Conservation and Stewardship
> New Jersey Audubon Society
> __________________
>
> 11 Hardscrabble Road
> Bernardsville, New Jersey 07924
>
> Phone: 908.766.5787 ext 13 Fax: 908.766.7775
> Website: www.njaudubon.org/conservation
>
> Conserving New Jersey's Natural Heritage Since 1897
>
|
