Hugo, Michael and others,
Sorry to drag this out, but I'm still not completely satisfied.
Hugo Phillipps wrote:
> Different people have followed different conventions. I would consider
> successful breeding (raising young to the point of independence and sexual
> maturity) is an important step that should be recognised. When a
> population (not just a single pair) breeds successfully (sustaining
> numbers) over a few generations, that is another. So, when atlassing
> marginal or newly established populations of ferals it is especially
> important to record breeding.
I would agree with you that successful breeding and maintenance of a population
over several years are necessary criteria for a recently introduced population
of
a species to be recognised as established, thereby warranting its inclusion on
distribution maps in field guides. However, the nitty gritty of these criteria
you present are still missing. How many generations of breeding must occur or
how
many years must a population be self-sustaining before it is granted such
recognition? This was the detail requested in Michael Atzeni's original enquiry,
I believe.
As you say, different conventions are followed by different people. Perhaps it
would be instructive to hear what criteria the Atlas will use to decide on
whether to include 'feral populations' in their new distribution maps. Will
they
use the '10-year rule' or some other decision system?
This raises another question. If the 1984 RAOU Atlas does not indicate
Long-billed Corellas in Queensland, for example, will they be included in the
new Atlas based on the distribution snapshot received over the next few years?
Wouldn't inclusion require longer term records demonstrating that particular
populations were present and breeding at specific sites over the prescribed
period (e.g. 10 years, or x generations) or will records gathered over the four
year life of the project suffice?
In Queensland, another species for which this whole issue is pertinent is the
Red-whiskered Bulbul which has been in the Mackay area (and perhaps elsewhere)
for quite some time, yet does not appear in the various field guides. Common
sense indicates this population should be included on distribution maps and the
State list of birds, but the formal criteria for supporting such an inclusion
are
vague.
Any guidance and suggestions would be welcomed.
Cheers,
Ian
--
+----------------------------------------+
Dr Ian Gynther
Senior Conservation Officer
Research Coordination Unit
Planning and Research Division
Queensland Parks and Wildlife Service
PO Box 155
Brisbane Albert St. QLD 4002
Tel: (07) 3227 7055 Fax: (07) 3227 6386
E-mail:
Visit us online at http://www.env.qld.gov.au
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