Hi Peter
More correct to say that populations of some of these species haven't been
sustained in the Otways, rather than that no birds made the trip - they may
have been there and disappeared - though it's hard to imagine Eastern
Whipbirds and Superb Lyrebirds making much headway through grassland and
grassy woodland if we were starting from scratch :-)
The land clearing you mention is of course the important contemporary story
- extinction debt is alive and "well"!
L.
On 12/03/2008, <>
wrote:
>
> I think this is a great case study for the conservation of sedentary and
> habitat restricted species.
>
> The distance between the southern end of the Great Dividing Range and the
> beginning of the otways couldn't be more than 100-150km apart. And the
> minimum distance that a species would have to travel over an 'inhospitable
> biogoegraphic barrier' would be about 50-70km.
>
> For such a short distance, it seems that no habitat restricted species has
> been able to make the journey in over 6,000 years! (probably extending to a
> few hundred thousand years)
>
> The land clearing that has occurred in the last 200 years in the Great
> Dividiing Range has introduced expanses a lot bigger than 50km. So what
> strains are we putting on genetic diversity of such species???
>
> Peter
>
>
>
>
>
> *"Lawrie Conole" <>*
> Sent by:
>
> 12/03/2008 11:31 AM
> To
> "Birding Aus" <> cc
>
> Subject
> [Birding-Aus] re: Otways- Eastern Whipbird, Superb Lyrebird?
>
>
>
>
>
>
> Regarding the absence of a range of typical east coast wet forest birds
> from
> the Otway Ranges in SW Victoria, you need to think back in time - way back
> in time! The landscape has changed a lot in the last few hundred thousand
> years - particularly in configuration as well as nature of habitat blocks.
>
> One of the most important factors in differentiating SW Victoria's
> avifauna
> from the otherwise continuous East Coast/Great Dividing Range would have
> to
> be the enormous and inhospitable biogeographic barrier called the
> Victorian
> Volcanic Plain. Consider that Red-browed Treecreeper occurs all the way
> west to near Daylesford on the Great Divide; Superb Lyrebirds, Pilotbirds,
> Large-billed Scrubwrens and Lewin's Honeyeaters peter out around the west
> end of the Kinglake Plateau and Mt Disappointment - all of these contained
> within the relatively continuous Great Dividing Range wet forests.
> Pilotbirds are more or less replaced by Rufous Bristlebirds in the Otways.
>
> It would be very surprising indeed if there were anything functionally
> "wrong" with the Otway forests to explain the mildly depauperate avifauna
> -
> more likely it's simple species turnover from relative isolation. Some
> typical wet forest birds are still there (residents and migrants - Satin
> Bowerbird; King Parrot; Gang-gang; Flame, Pink & Rose Robin, Rufous
> Fantail,
> Brush Cuckoo, Bassian Thrush, Olive Whistler, Satin Flycatcher) - and some
> continue on into other relict populations even as far west as the South
> Australian border (Rose Robin, Gang-gang Cockatoo, etc.). Some wet forest
> mammals occur well west in isolated outliers of the Great Dividing Range
> through central Victoria (Mountain Brushtail Possums at Mount Cole near
> Ararat; various species in the Grampians and Otways). All looking like
> bits
> and pieces of a formerly more extensive wet forest landscape.
>
> There are in fact some apocryphal stories about odd lyrebirds seen in the
> central Otway Range (e.g. one during Atlas I on Cape Otway, May 1977 -
> from
> Pescott 1983), but nobody seriously believes these are representative of
> relict local populations - rather they are misidentifications, wishful
> thinking, or escaped/liberated captive birds.
>
> --
> ++++++++++++
> Lawrie Conole
> 28 Reid Street
> Northcote, VIC 3070
> AUSTRALIA
> lconole[at]gmail.com
> 0419 588 993
>
>
> REFERENCE
>
> Pescott, T. (1983). 'Birds of Geelong.' (Neptune Press: Newtown).
> ===============================
> www.birding-aus.org
> birding-aus.blogspot.com
>
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--
++++++++++++
Lawrie Conole
28 Reid Street
Northcote, VIC 3070
AUSTRALIA
lconole[at]gmail.com
0419 588 993
===============================
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