Maria Merkling Havens wrote:
>
> Was nobody (at Birds Australia in particular) given advance warning
> that this story was to air tonight? I for one would have loved a
> heads-up to get some tape in the VCR.
The transcript should appear on the 7.30 website. However, I think this
transcript from Ockham's Razor has far more info than the 7.30 segment
LK
_______________________________________________________________________________
http://www.abc.net.au/rn/science/ockham/stories/s201833.htm
Ockham?s Razor
with Robyn Williams
on Sunday 22/10/00
The Mount Lofty Ranges Spotted Quail Thrush
Summary:
The Mount Lofty Ranges spotted quail thrush, found only in the hills
around Adelaide, is Australia's most endangered bird.
Transcript:
Robyn Williams: Scott Field is a lecturer in conservation biology at
the University of Adelaide and he wants to put a direct question to you
today: Do you care whether the spotted quail thrush, usually found
around the Mount Lofty Ranges, goes extinct? Had you ever heard of it
before? Why worry about one more little bird, when we have so many? How
will this little creature make a difference?
Well as Australia turns its attention at this time of year to matters
of ornithology, here?s Scott Field to put the case.
Scott Field: It?s official: the Mount Lofty Ranges spotted quail
thrush, a rare sub-species of bird found only in the hills around
Adelaide, is Australia?s most endangered bird. That?s according to the
country?s premier bird research and conservation organisation, Birds
Australia, which has just released its Action Plan for Australian
Birds, a report tabling the status of all 1274 species and sub-species
of Australian birds, a staggering 264, or 21% of which are threatened,
and around 70 of which are in imminent danger of disappearing forever.
As I speak, the Mount Lofty Ranges spotted quail thrush hovers on the
brink of extinction, in fact for all we know it might be gone already.
The last confirmed sighting was way back in 1984, at a location known
only to a handful of people. For the past 18 years no-one has seen hide
nor hair of this shy, ground-dwelling bird, which once roamed the ranges
in its hundreds. Even if it is still alive out there, it is almost
certain doomed to extinction in the near future. Another one, as they
say, bites the dust.
?So what?? I hear 99% of Australia?s population say. Truth is the vast
majority of people have never even heard of a spotted quail thrush,
wouldn?t have a clue what it looks like, and certainly won?t miss it
once it?s gone. A handful of people might feel momentarily saddened by
the news, perhaps a few will feel guilty they haven?t done more to
support conservation, but most will just shrug their shoulders and go
back to whatever they were doing. And it?s easy to see why. Why exactly
should they care that an obscure bird they?ve never heard of before is
disappearing? Answering that question has always been one of the
thorniest problems facing the advocates of conservation, and that?s what
I want to talk about today.
The first point is something the Bird Action Plan makes abundantly
clear: the spotted quail thrush is not alone. Just in the Mount Lofty
Ranges, a full 13 species are on the threatened or endangered list.
Local research also indicates that at least another dozen are declining
in number and may be on the way out. And that?s to say nothing of the
seven that have already been officially driven extinct. Adelaide
residents will never again see azure kingfishers plunging into their
streams, glossy black cockatoos cracking seed-pods on their sheoaks, or
a rusty field-wren singing its heart out from the top of a bush. They?ll
never again be startled when a king quail or a swamp parrot suddenly
flushes from its hiding place at their feet, or be suddenly distracted
by the flash of gold on black as a regent honeyeater careers through the
treetops. Why? What?s happened, in the last 40-odd years, to make some
30 or more bird species either disappear or begin spiralling towards
extinction?
In keeping with the spirit of Ockham?s Razor, we can offer one very
simple answer, that most everyone agrees is of overwhelming importance:
Vegetation clearance. When Stephen Garnett and Gabriel Crowley, the
authors of the Bird Action Plan, chose the spotted quail thrush to be
the standard-bearer for Australian bird extinctions, they did so for a
reason. In their own words, it is ?a symbol of the destruction of the
once extensive island of forest that for thousands of years clothed the
Mount Lofty Ranges.? The fact is, that of the half a million or so
hectares of magnificent eucalypt woodland that once covered the Mount
Lofty Ranges, a meagre 10% remains. And even this is really understating
the problem, because almost none of this is intact, old growth forest.
Virtually every stand of native vegetation we have left has been logged,
disturbed, or otherwise exploited at one time or another. And what we,
and future generations have been left with as a consequence, is what?s
known in ecological circles as an ?extinction debt?. This is a
collective social and ecological debt that is unfolding on a scale to
rival even our shameful State Bank fiasco.
It?s this concept of the extinction debt that can help us understand
why even today, some 20 years after legislation was passed to halt
vegetation clearance in the Mount Lofty Ranges, extinctions continue to
roll on. The idea behind an extinction debt is that there is usually a
time lag, anywhere from a decade to a century or more, between a block
of scrub being bulldozed, and the final extinction of a species that
relied on that patch as its population stronghold. Maybe there could be
small isolated populations of the species elsewhere that can struggle on
for a generation or two, before they finally wink out of existence as
well. And once a population has been whittled down to, say, fewer than
500 individuals, its long-term chance of survival is almost zero. This
is because when the population is that small, it?s inevitable that
sooner or later chance events like fires and disease epidemics, or human
introductions like feral predators or invasive weeds are going to catch
up with them. These species are living on borrowed time.
Back in 1980, ecologists calculated the size of our bird extinction
debt in the Mount Lofty Ranges, and came up with a figure of 35 to 50
species, that?s almost half the birds originally inhabiting the region.
Local authorities have little doubt we are well on the way to seeing
that gloomy prediction become reality.
So when we hear about a single bird species like the spotted quail
thrush going to the wall, we shouldn?t be fooled into thinking it?s an
obscure, isolated, one-off case. The point to remember is that the
impacts of habitat loss take place on a relatively long time-scale, an
ecological time-scale. So yes, vegetation clearance in the Mount Lofty
Ranges might have ended more or less, 20 years ago, but the ecological
effects of past losses will continue to rumble on for decades to come.
And birds are just one small part of the biodiversity story. We know
very little to nothing of extinction rates in the massively diverse
groups like insects and fungi. But it?s safe to assume that the species
losses from these groups are orders of magnitude worse than those for
birds.
Another reason to care about all this is that if we act quickly, there
is possibly something that can be done. One thing that?s essential is to
formulate a long-term strategy to at least partially reconstruct the
natural landscape we have decimated. Ecologists generally agree on a 30%
rule of thumb for ecosystem function; once a region has been denuded of
70% of its primary vegetation cover, it crosses a threshold beyond which
ecosystem processes rapidly begin to crumble and whole suites of species
begin to decline. Restoring 30% of the natural vegetation in the Mount
Lofty Ranges is a daunting task, but a target for ecological
sustainability we must start lobbying for, and planning towards.
What makes the challenge of landscape reconstruction all the more
daunting is that we don?t yet have much of a clue as to how to go about
doing it. How do you put a jigsaw back together when half the pieces are
missing? The theory and practice of landscape reconstruction is one of
the great emerging research frontiers of Australian science. One of the
key considerations is how best to arrange the patches of vegetation
across the region. Do we focus on consolidating the large existing
blocks of scrub and making them bigger? On building corridors between
adjacent patches? Should we re-vegetate barren land from scratch, and if
so, what shape of patch will work best, how big should it be and how
close to other patches in order to remain viable? When questions like
these are considered at a landscape scale in a place like the Mount
Lofty Ranges, which has been chopped and diced into literally hundreds
of patches, all varying in their size, condition and spatial context,
the problem becomes almost overwhelming.
In our ecological modelling research group, based at the Universities
of Queensland and Adelaide, we are looking at the problem of optimising
landscape reconstruction for bird diversity, and break it down into a
three-step process. The first step is to conduct bird surveys in a
selection of remnant patches of bush, to see which birds have managed to
survive in which patches and try and understand why. By looking at a
range of patch characteristics like size, shape, proximity to other
patches, the land forms it includes, plant species, vegetation structure
and so forth, we can deduce which of those features are good indicators
that a particular bird will live in a certain kind of patch. Then in
step two, we can make predictions about which birds will be living in
the remaining patches, the ones we didn?t have a chance to survey. What
we end up with then is a landscape map of all the patches in the region,
and for each one an estimate of which species will be living there, and
also the total species richness and diversity the region can support.
That map is the crucial tool for progressing to step three. By feeding
its contents into some industrial-strength computing algorithms, we can
begin exploring all the millions of different landscape reconstruction
options and see which of them are likely to produce the greatest
possible biodiversity benefits across the entire region.
But while all this is very nice in theory, we certainly can?t afford to
pin all our hopes for averting extinctions on landscape reconstruction.
Even once we work out a strategy, chances are it will take a century or
more to implement, and by that time, it seems certain that many of the
species we?re aiming to save will long since have vanished. So in the
short term, an equally urgent priority is to find out for each species,
which of the multitude of threatening processes we humans have inflicted
on them is affecting them the most, and what we can do to lessen those
effects.
To make our task more urgent, we also can?t afford to get our research
strategies wrong, for two reasons. First, the market-driven economic
table from which conservationists occasionally snatch a few scraps of
funding will exercise very little tolerance for failure. Second, the
time window in which we can actually pay down our extinction debt, and
reverse the ecological tide is whizzing by at an alarming rate. Inaction
or incompetence today will translate directly into extinctions in a
generation?s time.
Many city-dwelling Adelaideans no doubt feel comforted when they look
up from the plains and see an ocean of green cradling their city. Indeed
they are among the privileged few in the world who can do so. Adelaide
is in some senses a world leader in conservation, with one of the first
national parks in the world at Belair, some of the world?s earliest
legislation against land clearance, and a visionary mandate for
protection of the Hills Face Zone. But these innovations have come about
only because Adelaide has also been a world leader in environmental
destruction. It was not a prophetic sense of environmental
responsibility that led us to act first, but rather the state of crisis
brought about by the astonishing rate at which the Adelaide plains and
Mount Lofty Ranges were ecologically disembowelled after European
settlement.
Given this historical precedent, it is difficult to fathom why States
like Queensland seem intent on going down the same path. Recent figures
show that every year Australia now clears an area equivalent to the
entire Mount Lofty Ranges, that?s half a million hectares, and 80% of
this destruction takes place in Queensland. Land clearance legislation
was recently watered down so that only those ecosystem types down to 10%
representation could be protected. Ten percent, the same disastrous
level of clearance we are suffering from here in the Mount Lofty Ranges.
This blind charge of clearing places Australia in the elite company of
the top five land clearance nations in the world, along with Brazil, the
Congo, Bolivia and Indonesia. The act of land clearance alone directly
kills about 7-1/2-million individual birds a year, and through the
extinction debt effect will be indirectly responsible for the decline
and extinction of entire species for decades to come. Coupled with the
well-documented effects of land degradation that accompany land
clearance, currently costing the nation over a billion dollars a year in
lost agricultural production, the trend is towards both ecological and
economic disaster. Even if one wasn?t bothered at all about the loss of
our unique wildlife, 80% of which is found only in Australia and can
never be replaced, the long-term economic costs are reason enough to
care about the unfolding national disaster so aptly symbolised by the
plight of the Mount Lofty Ranges spotted quail thrush.
Robyn Williams: Scott Field, from the Waite Institute, University of
Adelaide. And let?s hope the little quail thrush is saved.
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
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