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Scott & Steve,
Scott's comments are quite correct. I haven't
seen the article but I suspect that the newsworthiness could be that someone has
recently rediscovered that someone called Allee, decades ago, documented
principles that are now being re-established independently. Not that his
observations are different from new knowledge but that it is now thought that
the "new" knowledge is not so new after all and so it is a pity that
these principles were "discredited and largely forgotten". The path of
science has many twists like this.
Just like the genetic
discoveries by Gregor Mendell were totally ignored for about 80 years (or lesser
but still a real long time), even though they would have been of immense value
to Charles Darwin, who never was aware of them.
Philip
-----Original Message-----
From:
Scott O'Keeffe <>
To:
<>;
<>
Date:
Friday, 9 February 2001 19:52
Subject: RE: [BIRDING-AUS]
Serendipity
Steve-
Whatever the New Scientist
article may say, these are hardly new ideas for
ecologists or population
biologists. Is there something you havn't told us
about the
article? Or maybe there is something else the article hasn't
told
us about Allee's ideas?
Scott
O'Keeffe
-----Original Message-----
From:
[m("lists.vicnet.net.au","owner-birding-aus");">]On
Behalf Of
Sent:
09 February 2001 13:34
To:
Subject:
[BIRDING-AUS] Serendipity
G'day all
A couple of
days ago I was rambling on about a theory for the declinme of
some
of
our woodland birds. It had to do with little islands
of favoured
habitiat in forests and a birds reluctance to leave one
island
and
colonise the next one.
Reading the latest New
Scientist (3rd Feb) today I came across an article
entitled "Safety
in numbers".
It discusses how , for some animal species,
undercrowding can lead to
extinction. Apparently a US
zoologist
named Warder Allee (1885-1955) studied this in the 1940's but
his ideas were
discredited and largely forgotten.
Now, however,
"an awareness of these Allee effects looks set to
transform
conservation practices."
"Allee effects centre
on the observation that some species find it difficult
to
breed
successfully once the population
falls below a certain number or
density"
There are several Allee effects that result from
undercrowding:-
Harder to find mates (Blue Whales)
Species where
males gather together to stimulate one another for
breeding
(Kakapo)
Reduced predator protection (Flamingos, Banded
Stilts)
Cooperative breeders finding themselves without helpers (African
hunting
dogs,
White-winged Choughs)
It is a nice bt of
serendipity and I would like to hear the thoughts of any
of
the
ornithologists on birding-aus about Allee effects.
Please don't get too
technical
though.
Cheers
Steve
*********************************************************
Steve
Clark
Hamilton, Victoria, 3300
HTTP://www.ansonic.com.au/clarks/sw_birds.htm
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