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Impacts of Landclearing: the impacts of the approved clearing of native vegetation on Australian wildlife in New South Wales

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Abstract and Figures

This report uses the amount of land in New South Wales approved by the State Government for clearing between 1998 and 2005 inclusively to calculate the impacts of land clearing on the State’s wildlife. According to these calculations more than 104 million native mammals, birds and reptiles have died or will die as a result of the clearing of native vegetation in NSW approved between 1998 and 2005. These include: • over 11 million mammals with possums and gliders most severely affected as well as many millions of kangaroos, wallabies, bandicoots, koalas and wombats; • around 13 million birds comprising mostly woodland and forest birds and including species of honeyeaters and babblers that are under threat of extinction in NSW; and • more than 80 million reptiles such as skinks and geckos. These estimates are highly conservative and the true mortality is likely to be substantially higher than those estimated in this report. Due to inadequate or uncertain public data, the figures in this study do not include the numbers of animals killed as a result of illegal clearing that occurred in NSW from 1998 to 2005, or as a result of exempt clearing (i.e. legally permitted clearing that does not require approval) that occurred during this time. These other clearing activities also result in the deaths of many millions of native animals. For example, around 5 million mammals, birds and reptiles would have been killed by the amount of illegal clearing estimated by the Auditor-General to have occurred in 2005. This study does not include any estimates of the amphibians, fish and invertebrates that were also killed as a direct or indirect result of the approved clearing of native vegetation. The study used the known record of approved clearing of native vegetation in NSW from 1998 to 2005 inclusively that was published by the Auditor-General in his 2006 report, Regulating the Clearing of Native Vegetation: Follow-up of 2002 Performance Audit. Between 1998 and 2005 inclusively, the NSW Government approved 639,930 hectares for clearing under its native vegetation legislation. NSW’s wildlife is seriously threatened and under increasing pressure from a range of traditional threats, such as the clearing of native vegetation and the impacts of exotic pests, as well as more recent factors, such as climate change. NSW can stop the loss and degradation of valuable habitats immediately by arresting the extent of clearing and fragmentation of native vegetation, particularly west of the Great Dividing Range, and by undertaking the level of research and monitoring that is essential to managing natural resources at sustainable levels. Alternatively, NSW can continue to allow native habitats to be lost or degraded and experience irreversible regional population declines and extinctions.
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The Impacts of the Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales
LANDCLEARING
IMPACTS OF
bImpacts of Land Clearing
WWF-Australia
WHEN LAND
IS CLEARED,
EVERYTHING
THAT LIVES IN
IT IS KILLED.
– AUSTRALIA STATE OF THE ENVIRONMENT 2006
© Viewfinder
© WWF-Australia. All Rights Reserved.
WWF-Australia Head Office
GPO Box 528, Sydney, NSW, Australia 2001
Tel: +612 9281 5515 Fax: +612 9281 1060
wwf.org.au
Published February 2007 by WWF-Australia. Any reproduction in full or in part of this publication
must mention the title and credit the above-mentioned publisher as the copyright owner.
The opinions expressed in this publication are those of the author and do not necessarily reflect
the views of WWF.
For bibliographic purposes this report should be cited as:
Johnson, C., Cogger, H., Dickman, C. and Ford, H. 2007. Impacts of Landclearing; The
Impacts of Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales.
WWF-Australia Report, WWF-Australia, Sydney.
ISBN: 1 921031 17 4
World Wide Fund for Nature ABN: 57 001 594 074
1
Impacts of Land Clearing
WWF-Australia
CONTENTS
ABOUT THE AUTHORS 2
EXECUTIVE SUMMARY 4
1. BACKGROUND 6
2. MAMMALS 12
3. BIRDS 20
4. REPTILES 28
5. CONCLUSION 34
REFERENCES 36
2Impacts of Land Clearing
WWF-Australia
DR HAL COGGER
REPTILES
Dr Hal Cogger is a leading Australian herpetologist and author of the
definitive Reptiles and Amphibians of Australia. He is a former Deputy
Director of the Australian Museum.
Dr Cogger has participated on a range of policy and scientific committees,
including the Commonwealth Biological Diversity Advisory Committee,
Chair of the Australian Biological Resources Study Advisory Committee
and Chair of the Australasian Reptile & Amphibian Specialist Group
(IUCN’s Species Survival Commission). He also held a Conjoint
Professorship in the Faculty of Science & Mathematics at the University
of Newcastle (1997-2001).
He is currently the John Evans Memorial Fellow at the Australian Museum.
Hal Cogger’s research interests include the systematics and ecology
of Australian reptiles and frogs and the role of threatened species in
conservation biology and policy development. He is senior author of the
Action Plan for Australian Reptiles.
For his contribution to Australian herpetology, Dr Cogger has been
awarded an AM, an honorary Doctor of Science from the University
of Sydney, and honorary life memberships of the Australian Society of
Herpetologists, the American Society of Ichthyologists and Herpetologists
and The Herpetologists’ League, Inc. He is a recipient of the Whitley
Medal of the Royal Zoological Society of NSW.
PROFESSOR CHRIS DICKMAN
MAMMALS
Professor Chris Dickman is a highly respected scientist with nearly
30 years’ experience of working on the ecology, conservation and
management of Australian mammals. Since 1990, he has been Director of
the Institute of Wildlife Research at the University of Sydney. In 2004, he
was awarded a personal chair in ecology at the university.
For much of the last 20 years, Professor Dickman has studied the factors
that influence vertebrate diversity in arid Australia. In this work, he has
identified habitat loss, feral cats and foxes as being particularly detrimental
to the survival of native fauna.
Professor Dickman is a past President of the Australian Mammal Society and
of the Royal Zoological Society of New South Wales, past Chair of the NSW
Scientific Committee, and Chair of the Australian Marsupial and Monotreme
Specialist Group for the Species Survival Commission of the IUCN.
Professor Dickman currently serves on the national assessment panel for
the Threatened Species Network Community Grants Program, the NSW
Biodiversity Research Network, and the Scientific Advisory Committee for
Earthwatch.
Professor Dickman has written or edited 16 books and monographs and
authored a further 220 journal articles and book chapters. He is a recipient of
a Bolliger Award and Troughton Medal from the Australian Mammal Society.
In 2001, he was elected a Fellow of the Royal Zoological Society of
New South Wales. Professor Dickman is a WWF-Australia Governor and
former member of WWF’s Scientific Advisory Panel.
ABOUT
THE
AUTHORS
3
Impacts of Land Clearing
WWF-Australia
PROFESSOR HUGH FORD
BIRDS
Professor Hugh Ford is one of Australia’s most senior and respected bird
scientists. He has over 30 years of experience in the ecology, behaviour
and conservation of Australian birds, especially those of eucalypt forests
and woodlands.
Until recently, Professor Ford was Head of the School of Environmental
Sciences and Natural Resources Management, University of New England.
Professor Ford is the author of Ecology of Birds: An Australian Perspective.
He has edited two books on Australian birds and authored over 100 (book)
chapters and journal articles.
In 1980, Professor Ford and Dr Howe published a landmark study of
the long-term conservation status of birds in the Mount Lofty Ranges of
South Australia. Using island biogeography principles, the two scientists
predicted that of the original terrestrial bird fauna of about 120 species,
almost 50 would eventually become extinct. This was the first Australian
study alerting us to the problem of an ‘extinction debt’. The recently
started Mount Lofty Birds for Biodiversity Regional Recovery Project
aims to tackle this problem.
In 1993, Hugh Ford was awarded the Serventy Medal for ‘Outstanding
Services to Ornithology in the Australasian region’ by the Royal
Australasian Ornithologists Union.
Hugh Ford conducted a major project on the impact of habitat loss,
fragmentation and degradation on birds with Professor Harry Recher,
Dr Denis Saunders and Dr Geoff Barrett, which was supported by
WWF-Australia in the early 1990s.
Professor Ford is a Governor of WWF-Australia and was formerly
a member of WWF’s Scientific Advisory Panel. He is also a member
of the Research and Conservation Committee of Birds Australia.
4Impacts of Land Clearing
WWF-Australia
This report uses the amount of land
in New South Wales approved by
the State Government for clearing
between 1998 and 2005 inclusively
to calculate the impacts of land
clearing on the State’s wildlife.
According to these calculations
more than 104 million native
mammals, birds and reptiles have
died or will die as a result of the
clearing of native vegetation
in NSW approved between 1998
and 2005.
These include:
over 11 million mammals with
possums and gliders most
severely affected as well as
many millions of kangaroos,
wallabies, bandicoots, koalas
and wombats;
around 13 million birds
comprising mostly woodland
and forest birds and including
species of honeyeaters and
babblers that are under threat
of extinction in NSW; and
more than 80 million reptiles
such as skinks and geckos.
These estimates are highly
conservative and the true mortality
is likely to be substantially higher
than those estimated in this report.
Due to inadequate or uncertain
public data, the figures in this
study do not include the numbers
of animals killed as a result of
illegal clearing that occurred in
NSW from 1998 to 2005, or as
a result of exempt clearing (ie
legally permitted clearing that
does not require approval) that
occurred during this time. These
other clearing activities also result
in the deaths of many millions
of native animals. For example,
around 5 million mammals, birds
and reptiles would have been killed
by the amount of illegal clearing
estimated by the Auditor-General
to have occurred in 2005.
This study does not include any
estimates of the amphibians, fish
and invertebrates that were also
killed as a direct or indirect
result of the approved clearing
of native vegetation.
The study used the known record
of approved clearing of native
vegetation in NSW from 1998 to
2005 inclusively that was published
by the Auditor-General in his 2006
report, Regulating the Clearing of
Native Vegetation: Follow-up of
2002 Performance Audit. Between
1998 and 2005 inclusively, the
NSW Government approved
639,930 hectares for clearing under
its native vegetation legislation.
NSW’s wildlife is seriously
threatened and under increasing
pressure from a range of traditional
threats, such as the clearing of
native vegetation and the impacts
of exotic pests, as well as more
recent factors, such as climate
change. NSW can stop the loss and
degradation of valuable habitats
immediately by arresting the extent
of clearing and fragmentation of
native vegetation, particularly west
of the Great Dividing Range, and
by undertaking the level of research
and monitoring that is essential
to managing natural resources at
sustainable levels. Alternatively,
NSW can continue to allow native
habitats to be lost or degraded
and experience irreversible regional
population declines
and extinctions.
EXECUTIVE
SUMMARY
5
Impacts of Land Clearing
WWF-Australia
According to these calculations more than
104 million native mammals, birds and reptiles
have died or will die as a result of the clearing
of native vegetation in NSW approved between
1998 and 2005.
© WWF-Canon, Martin HARVEY
6Impacts of Land Clearing
WWF-Australia
1.1
IMPACTS ON
WILDLIFE
OF LOSS
OF NATIVE
VEGETATION
The Australia State of the
Environment 2006 report states that
when land is cleared “everything
that lives in it is killed.1
The impacts of the loss of native
vegetation on Australian wildlife
are well recognised. For example,
the 2001 national report, Australia:
State of the Environment 2001,
identified the clearing of native
vegetation as the biggest threat to
Australia’s wildlife. The Australia
State of the Environment 2006
report identifies the clearing of
native vegetation as “an ongoing
threat to Australia’s environment”.2
The 2006 NSW State of the
Environment report also concluded
that the clearing of native
vegetation, with the associated
destruction of habitat, is “the
greatest single threat to biodiversity
in NSW”. 3
In 2003, the WWF-Australia
report, Impacts of Land Clearing
on Australian Wildlife in
Queensland, analysed the impacts
of the loss of native vegetation
on key elements of Queensland’s
wildlife.4 That report outlined the
profound effects, both immediate
and long-term, of the clearing of
native vegetation on the survival of
Australian wildlife, including the
deaths of many millions of native
mammals, birds and reptiles.
When an area of native bushland is
lost, most of the resident wildlife
does not simply relocate. In reality,
the vast majority of animals will
die. Most will die quickly but others
survive for a time before succumbing
to starvation, predation or other
fates. This can lead to the local and
regional extinction of populations
and, through successive cycles of
local impacts and fragmentation,
the decline and, in some cases,
extinction of entire species.
5
A further consequence of this
extinction process is that it can
take decades or more for the full
effects of land clearing to appear
– a time lag that is referred to as
an extinction debt. The debt arises
because we have “borrowed” rich
habitats for short-term gains and
reduced their diversity, adaptability
and long-term productivity through
loss of species richness. The
resultant debt is likely to fall due
in 20 to 50 or more years’ time and
will therefore be paid by future
generations as local extinctions
gradually become regional until
entire species are made extinct.6
As noted by the Australia State of
the Environment 2006 report, the
detrimental effects of vegetation
change extend “beyond the number
of hectares cleared or replanted
each year”. Any vegetation
that regrows or replaces cleared
vegetation, whether natural
regeneration or planted trees,
is rarely like the communities
that were previously cleared. For
example, dense woody shrubs
may form a monoculture in place
of a naturally occurring, complex
ecosystem.7 It also takes a very
long time for some components of
the ecosystem critical to wildlife
habitat to be replaced, such as tree
hollows, extensive areas of bark
and large trees.
1.2
PROTECTION
OF NATIVE
VEGETATION
IN NSW
It is almost a decade since a NSW
Government recognised through
legislation that the loss or clearing
of native vegetation causes serious
loss of biodiversity.8
In 1997, NSW passed the Native
Vegetation Conservation Act 1997
with the object of conserving and
managing native vegetation.9 In
2002, the Auditor-General found
that “the system for regulating the
clearing of native vegetation was
ineffective” due to deficiencies
in accountability, planning,
information, enforceability,
monitoring and reporting. As
noted by the Auditor-General in
2006, “this regulatory system
continued until December 2005
and continued to be ineffective”.10
In 2001, NSW formally listed
the clearing of native vegetation
under its Threatened Species
Conservation Act 1995 as a “key
threatening process” that harms
1. BACKGROUND
7
Impacts of Land Clearing
WWF-Australia
threatened species, populations or
ecological communities, or could
cause other species to become
threatened. At the same time, the
Scientific Committee established
by the Threatened Species
Conservation Act found that the
clearing of any area of native
vegetation in NSW, including areas
less than two hectares in extent,
may have significant impacts on
biological diversity.11
In 2003, the NSW Government
stated its “commitment to end
broadscale clearing and maintain
productive landscapes” 12 and
passed the Native Vegetation Act
2003. One of the main objects
of the legislation is to prevent the
clearing of any native vegetation
that has not been cleared since
1 January 1990 (or 1 January
1983 in the case of land in the
Western Division) unless
it improves or maintains
environmental outcomes. 13
This Act did not become
operational until 2005.
It is noted that the NSW legislative
regime is not supported by a
comprehensive mapping of
NSW native vegetation although
various studies have been made
in parts of the State over a long
time.14 Similarly, NSW has not
established a comprehensive
system for adequately monitoring
and reporting changes to the
State’s vegetation cover. Proper
monitoring of all the State’s
vegetation and a rigorous
classification system is essential
to enable future planning and
management of the State’s
resources and to ensure that
adequate and representative
protection of our biodiversity takes
place. This is crucial for a wide
variety of reasons, not the least to
ensure the continued functioning
of our landscapes and ecosystems.
When an area of native bushland is lost, most
of the resident wildlife does not simply relocate.
In reality, the vast majority of animals will die.
© Richard McLellan
8Impacts of Land Clearing
WWF-Australia
Figure 1. Map of existing native
vegetation in NSW, 200516
1. BACKGROUND
© WWF Canon / Michel DEPRAZ
Rainforests
Wet sclerophyll forests (shrubby subformation)
Wet sclerophyll forests (grassy subformation)
Grassy woodlands
Grasslands
Dry sclerophyll forests (shrub/grass subformation)
Dry sclerophyll forests (shrubby subformation)
Heathlands
Alpine complex
Freshwater wetlands
Forested wetlands
Saline wetlands
Semi-arid woodlands (grassy subformation)
Semi-arid woodlands (shrubby subformation)
Arid shrublands (chenopod subformation)
Arid shrublands (acacia subformation)
Cleared land
1.3
NATIVE VEGETATION LOSS IN NSW
NSW covers some 800,000 square kilometres of south eastern Australia.
It is a topographically complex region that includes more than one quarter
of the nation’s plant species and encompasses almost all of the major
environments represented in Australia.
NSW has already lost well over half of its native vegetation. Since 1788,
at least 61% of the original native vegetation of NSW has been cleared,
thinned or substantially or significantly disturbed. This figure exceeds
90 per cent in the case of some types of native environments such as the
south east grassy forests.15
The following map depicts the existing extent of native vegetation in NSW
in 2005.
9
Impacts of Land Clearing
WWF-Australia
During the years 1998 to 2005
inclusively, 639,930 hectares of
native vegetation was approved
for clearing in NSW. It is noted
that these figures do not include
areas of native vegetation subject
to illegal clearing or exempt
clearing (i.e. clearing that may be
legally carried out under the Native
Vegetation Act without approval).17
The table below sets out the
known record of clearing of native
vegetation approved by the NSW
Government in NSW from 1998
to 2005. The Auditor-General also
estimated that 30,000 hectares of
illegal clearing took place in 2005.
Approved clearing has been
greatest in areas to the west of the
Central Division for agriculture,
and in coastal regions for urban
development. The greatest area of
new clearing of native vegetation
in NSW since 1997 has taken place
in the central west and north west
of the State. Within these western
areas, the most intensive clearing
has been in the hotspot area around
Walgett, Nyngan and Tottenham.
New clearing in the State’s western
areas has been attributed to the
development of new strains of
wheat suitable for arid climates
which have provided a financial
incentive for clearing native
vegetation in areas previously
considered too arid for crops.19
In February 2007, the NSW
Government reported that, on
average, around 16,000-18,000
hectares of woody vegetation had
actually been cleared in NSW
during a two year period between
2004 and 2006.20 This compares
with the Auditor General’s estimate
of around 75,000 hectares for
2005 alone. The huge discrepancy
between the Auditor-General’s
figures and these latest findings
has not been comprehensively
explained. The NSW Government
also reported on new clearing
approvals for the first six months
of 2006.21
Year Hectares (approvals)
1998 73,735
1999 160,863
2000 74,459
2001 90,786
2002 57,753
2003 63,501
2004 73,951
2005 44,882
TOTAL 639,930
Table 1: Known record of approved clearing of native vegetation in
NSW, 1998-2005. 18
NSW has already lost well over half of its
native vegetation. Since 1788, at least 61%
of the original native vegetation of NSW
has been cleared, thinned or substantially
or significantly disturbed.
10 Impacts of Land Clearing
WWF-Australia
1.4
NSW WILDLIFE
UNDER THREAT
FROM LOSS
OF NATIVE
VEGETATION
Significant loss of native vegetation
and the associated destruction of
habitat continues to occur in NSW
despite the fact that NSW wildlife
is already under siege.
In NSW, 315 animal species or
populations are listed as threatened
with Statewide extinction.22 This
comprises:
amphibians – 27;
aquatic invertebrates – 3;
bats – 21;
birds – 115;
endangered populations – 36;
fish – 12;
invertebrates – 14;
marine mammals – 7;
marsupials – 24;
reptiles – 44; and
rodents – 12.23
Eighty-two per cent of the
terrestrial or non-marine
species had the clearing of
native vegetation listed as a key
threatening process under the
NSW Threatened Species
Conservation Act.
The following table sets out the
numbers of terrestrial or non-
marine mammals, birds and reptiles
listed by NSW as threatened
with Statewide extinction and the
number having land clearing as a
key threatening process.
No.
threatened
No. with land
clearing as
key threaten-
ing process
Percentage of
species having
land clearing as
key threatening
process
Mammals
(terrestrial)
57 49 86%
Birds
(non-marine,
not offshore)
88 72 82%
Reptiles
(terrestrial)
36 28 78%
TOTAL 181 149 82%
Table 2: Terrestrial or non-marine mammals, birds and reptiles
listed by NSW as threatened with Statewide extinction by the end
of 2006 and the number having land clearing as a key threatening
process under the NSW Threatened Species Conservation Act 24
1. BACKGROUND
11
Impacts of Land Clearing
WWF-Australia
1.5
METHODOLOGY
• Information on native vegetation change
The calculations in this report are based on the known record of approved
clearing of native vegetation between 1998 and 2005 published by the
NSW Auditor-General in the 2006 report, Regulating the Clearing of
Native Vegetation. Follow-up of 2002 Performance Audit. 25
The figures reported by the Auditor-General are not a complete record
of the clearing of native vegetation in NSW for the subject time period.
Instead, the Auditor-General’s report figures comprise only the area subject
to approvals under the previously applicable legislation (being the Native
Vegetation Conservation Act 1997)26 and an estimate of illegal clearing
in 2005.
• Calculation of wildlife impacts
Given Australia’s megadiversity of species and our comparatively small
human population and research base, the density (ie number of individuals
in a given area) of relatively few species has been determined with
precision. In addition, the number of different species, or species richness,
occurring in a given area is not known in great detail for many habitats.
Estimates of these values must necessarily be extrapolated from a relatively
small number of detailed studies. Therefore the authors have deliberately
employed highly conservative estimates in making their calculations. The
true mortality is likely to be substantially higher than those estimated in
this report.
© Bruce Thomson, auswildlife.com
12 Impacts of Land Clearing
WWF-Australia
2.1
OVERVIEW
Australia supports a rich and
impressive diversity of mammals,
with over 300 native species
occupying the land.27 The
continent is unique in being
dominated by marsupials, and in
being the only great land mass to
contain representatives of the three
major groups of living mammals:
the marsupials, monotremes (the
egg-laying platypus and echidna)
and placentals. About 244 species,
or 81% of this distinctive fauna,
are found only in Australia, with
the others occurring also in the
New Guinea region.28 Some 27
species and subspecies of native
mammals have become extinct in
Australia over the last 200 years,
the highest rate of loss for any
region in the world. 29
A detailed stock-taking in 1992
found records of 130 species of
native mammals in NSW.30 Of
these, 63 were marsupials, 28
were rodents and 37 were bats; the
two remaining species were the
echidna and platypus. Disturbingly,
the stock-take found that 27 of
the original species no longer
occurred in NSW, with eight of
these being extinct Australia-wide.
An additional 50 species were still
present but were threatened with
extinction in the future. Several
species have since been added
to the original stock-take due to
more survey work and taxonomic
revisions but the perilous state of
the majority of NSW mammals
remains unchanged.
In general, mammals are more
diverse and abundant in the higher
rainfall coastal regions of NSW
and on the slopes and tablelands
of the Great Dividing Range. These
regions remain the strongholds
for many of the tree-dwelling
marsupials, rodents and bats,
and provide the major refuges
for specialist species such as the
platypus and mountain pygmy-
possum. With declining rainfall
inland, tree cover becomes more
sparse and gives way in parts of
the far west of the State to arid
and semi-arid shrubland and
grassland. These drier habitats still
provide homes for many species
of native mammals, but the low
and uncertain productivity of the
environment means that these
species typically survive ‘on the
edge’ at lower and precariously
variable densities. Although there
is a lack of detailed information
on the types of vegetation that
are currently being cleared, the
available data indicate that large
areas of the central west and
Barwon regions are being affected,
as well as parts of the eastern
catchment of the Darling River.
Clearing in these areas removes
diverse vegetation types that can
be classified broadly as woodland
and parkland. Many mammals that
already occur sparsely in these
vegetation types are being pushed
to the brink of regional extinction,
and those with bigger populations
or broader geographical ranges
are being reduced, fragmented
and placed at future risk as more
vegetation is destroyed. Clearing
of vegetation in coastal areas for
development can also be expected
to have very negative consequences
for mammals, but there is no
reliable information on how much
vegetation is destroyed there.
2.2
NUMBERS OF
MAMMALS
KILLED BY
VEGETATION
LOSS IN NSW
• More than 11 million
native mammals died
or will die in NSW as
a result of the clearing
of native vegetation
approved between
1998 and 2005.
It is conservatively estimated that
over 11 million mammals will die
or have already died as a result of
land clearing approved in NSW
between 1998 and 2005 inclusively.
As noted previously, this estimate
does not include the number of
mammals killed by illegal or
exempt clearing. For example,
around half a million mammals
would have been killed by
the amount of illegal clearing
estimated by the Auditor-General
to have occurred in 2005.
2. MAMMALS
13
Impacts of Land Clearing
WWF-Australia
Possums and gliders are affected
most severely by clearing, with
common brushtail possums
(Trichosurus vulpecula), ringtail
possums (Pseudocheirus
peregrinus), feathertail gliders
(Acrobates pygmaeus), sugar and
squirrel gliders (Petaurus breviceps
and P. norfolcensis) suffering the
highest rates of mortality. Small
carnivorous marsupials are also
killed in large numbers each
year, with dunnarts (Sminthopsis
species) being most at risk in
central and western regions and
antechinuses (Antechinus species)
further east.
It is conservatively estimated that over 11 million
mammals will die or have already died as a result
of land clearing approved in NSW between 1998
and 2005 inclusively.
© Klein & Hubert
14 Impacts of Land Clearing
WWF-Australia
2.3
HOW HAVE
THESE
NUMBERS
BEEN
ESTIMATED?
The numbers of native mammals
killed by approved vegetation
clearing were estimated by, firstly,
obtaining estimates of mammal
population density in NSW and,
secondly, multiplying these density
estimates by the areas of vegetation
approved to be cleared in order to
obtain the numbers of mammals
impacted by the clearing process.
Estimates of density were obtained
from published studies of mammals
in NSW and from studies carried
out in other parts of Australia in
similar habitats to those present
in NSW (Table 3). Many of these
studies targeted just one or a small
number of species of mammals,
and these have been grouped
for simplicity into the broader
categories of possums and gliders,
native mice and rats, etc. When
averaged across the broad habitat
types in which the studies had been
conducted, mean densities for each
of the different mammal groups
ranged from 0.01 – 15.5 animals
per hectare, with higher values
being obtained usually in studies
carried out in coastal regions than
on the tablelands, western slopes
of the Great Dividing Range,
and plains. Because the most
clearing occurred in the central and
western regions of NSW, only the
lower density estimates were used
in analyses.
Estimates of population density
were based on species-specific
estimates as well as broader survey
studies that survey a range of
species in an area and sample the
various habitats that are available.
The following table sets out the
estimates of density of native
mammals from different habitats
and regions in NSW and total
numbers that have died or will
die as a result of land clearing
approved in 2005.
2. MAMMALS
© Chris Dickman
15
Impacts of Land Clearing
WWF-Australia
* Data sources: Abensperg-
Traun, M. 1990. Patch selection
and patch use in the echidna,
Tachyglossus aculeatus Shaw 1792
(Monotremata: Tachyglossidae),
in Western Australian wheatbelt
reserves. PhD thesis, University
of Western Australia; Barrott, E.
1999. Census techniques, habitat
use and distribution of koalas in the
Pilliga State Forests. Hons thesis,
University of Sydney; Dickman,
C.R. 1980. Ecological studies of
Antechinus stuartii and Antechinus
flavipes (Marsupialia: Dasyuridae)
in open-forest and woodland
habitats. Australian Zoologist 20:
433-446; Dickman, C.R. 1993.
The biology and management of
native rodents of the arid zone in
New South Wales. New South Wales
National Parks and Wildlife Service
Species Management Report 12:
1-149; Dickman, C.R. and
Read, D.G. 1992. The biology
and management of dasyurids
of the arid zone in New South
Wales. New South Wales National
Parks and Wildlife Service
Species Management Report
11: 1-112; Hartley, M. 2002.
Sarcoptes scabei var. wombati
infection in the common wombat
(Vombatus ursinus). M.Appl.
Sci. thesis, University of Sydney;
Kerle, J.A. 2001. Possums: the
Brushtails, Ringtails and Greater
Glider. University of New South
Wales Press: Sydney; Martin,
R.W. 1985. Overbrowsing, and
decline of a population of the
koala, Phascolarctos cinereus, in
Victoria III. Population dynamics.
Australian Wildlife Research 12:
377-385; Skerratt, L.F., Skerratt,
J.H.L., Banks, S., Martin, R. and
Handasyde, K. 2004. Aspects of
the ecology of common wombats
(Vombatus ursinus) at high density
on pastoral land in Victoria.
Australian Journal of Zoology
52: 303-330; Southwell, C. 1987.
Macropod studies at Wallaby
Creek II. Density and distribution
of macropod species in relation to
environmental variables. Australian
Wildlife Research 14: 15-33;
Tasker, E.M. 2002. The ecological
impacts of cattle grazing, and
associated grazier burning in the
eucalypt forests of northern NSW.
PhD thesis, University of Sydney:
Sydney; and numerous chapters in
books edited by Goldingay, R.L.
and Jackson, S.M. (eds). 2004. The
Biology of Australian Possums and
Gliders. Surrey Beatty & Sons:
Sydney; Grigg, G., Jarman, P. and
Hume, I. (eds). 1989. Kangaroos,
Wallabies and Rat-kangaroos.
Surrey Beatty & Sons: Sydney;
Jones, M.E., Dickman, C.R. and
Archer, M. (eds). 2003. Predators
with Pouches: The Biology of
Carnivorous Marsupials. CSIRO
Publishing: Melbourne; Lunney,
D. (ed.). 1991. Conservation of
Australia’s Forest Fauna. Royal
Zoological Society of New South
Wales: Sydney; Lunney, D. (ed.).
2004. Conservation of Australia’s
Forest Fauna, 2nd edition. Royal
Zoological Society of New South
Wales: Sydney; Lunney, D.,
Urquhart, C.A. and Reed, P. (eds).
1990. Koala Summit: Managing
Koalas in New South Wales. NSW
National Parks and Wildlife Service:
Sydney; Seebeck, J.H., Brown, P.R.,
Wallis, R.L. and Kemper, C.M.
(eds). 1990. Bandicoots and Bilbies.
Surrey Beatty & Sons: Sydney;
Smith, A. and Hume, I. (eds).
Possums and Gliders. Surrey Beatty
& Sons, and the Australian Mammal
Society: Sydney.
** Calculated using mean density
estimates of each mammal species /
group from the tablelands, western
slopes and plains.
Mammal species/
group
Coast and eastern
ranges
Tablelands, western
slopes and plains
Numbers killed by
approved clearing
per year (2005 data)**
Echidna 0.01 0.02 898
Koala 0.05 (<0.01 – 4.4) 0.08 (<0.01 – 2.1) 3,591
Common wombat 0.5 (0.01 – 1.9) 0.1 (<0.1 – 0.4) 4,488
Possums and gliders 15.5 (0.5 – 34.0) 7.0 (0.5 – 26.5) 314,174
Kangaroos, wallabies
and rat-kangaroos
0.8 (0.1 – 2.6) 0.5 (<0.1 – 1.0) 22,441
Bandicoots 2.1 (0.1 – 2.7) 1.7 76,299
Antechinuses,
dunnarts and other
carnivorous marsupials
9.5 (1.5 – 24.9) 3.8 (0.5 – 52.0) 170,552
Native mice and rats 2.9 (0.5 – 20.0) 4.3 (0 – 44.0) 192,993
Densities (numbers of animals per hectare) in
forest, woodland and scrub: means are shown
in bold with range, if available, in brackets*
Table 3: Estimates of density of native mammals from different habitats and regions, and total
numbers to be killed annually by land clearing approvals for 2005.
16 Impacts of Land Clearing
WWF-Australia
2.3
HOW HAVE
THESE
NUMBERS
BEEN
ESTIMATED?
Continued
Several decisions were taken that
have led to very conservative
estimates of numbers being made.
Specifically:
Many species were excluded
from estimates because there
is insufficient information on
their abundance. The largest
omission is the entire NSW bat
fauna (37 species), for which
no information on density could
be found.
Many small mammals in
semi-arid and arid regions
exhibit large fluctuations
in density depending on
the prevailing weather. For
example, historical accounts of
the long-haired or plague rat
(Rattus villosissimus) suggest
that densities well in excess of
1000 animals per hectare can
be attained after years of good
rain31, with the species virtually
disappearing again during
drought. For such eruptive
species, only the low-density
population estimates were used.
The densities of several
common species, such as the
brown antechinus (Antechinus
stuartii), agile antechinus
(A. agilis), yellow-footed
antechinus (A. flavipes) and
brushtail possum (Trichosurus
vulpecula) have been measured
in several studies, with most
yielding low to moderate
densities but small numbers
of studies yielding very high
estimates. To reduce bias
arising from these rare high
values, means for each species
were first calculated as log-
transformed densities and then
back-transformed to produce
normal values. This method was
used also by Cogger et al.32
Several species were omitted
from consideration due
to uncertainty about how
vegetation clearing would affect
them. Exclusions included red
kangaroos (Macropus rufus),
eastern grey (M. giganteus)
and western grey kangaroos
(M. fuliginosus), which can
flee clearing operations that
are in progress; rock-wallabies
(Petrogale species), platypus
(Ornithorhynchus anatinus),
the water rat (Hydromys
chrysogaster) and the dusky
hopping-mouse (Notomys
fuscus), as these species occupy
habitats not directly subject to
clearing; and species that are
largely restricted to arid desert
country with few trees and
shrubs (three species were in
this category, the planigales,
Planigale gilesi and
P. tenuirostris, and Forrest’s
mouse Leggadina forresti).
Although these latter species
sometimes occur in wooded
habitats, most records in NSW
are from open habitats that are
not likely to be cleared.33
As noted, the usually lower
densities obtained from studies
carried out in the tablelands,
western slopes and plains were
used in preference to the higher
estimates obtained in surveys
further east.
Despite the uncertainties inherent
in extrapolating numbers of
animal mortality over large
areas, the above points ensure
that the estimated numbers are
conservative. Omission of the
bat fauna alone will lead to a
substantial underestimation of
the true impact of vegetation
clearing, even though it is known
to be a highly destructive process
for many species34. In addition,
habitats near cleared areas are
usually reduced in quality due
to the effects of fragmentation
and processes that occur along
the boundary of the cleared area,
including increased access by pests
and feral predators such as foxes.35
Although these indirect effects of
vegetation clearing are less obvious
and longer-term, they highlight
the conservative nature of the
estimates that we provide here.
2.4
DO MAMMALS
DIE WHEN
THEIR NATIVE
HABITAT IS
CLEARED?
Does vegetation clearing actually
kill mammals, or simply displace
them? From an ecological
perspective, clearing of vegetation
has several immediate effects on
the mammals that use it. Some
individuals can be expected to die
of injury or trauma sustained during
the clearing process. For survivors,
clearing removes shelter from the
extremes of weather, cover from
predators, depletes or destroys food
resources, and disrupts the familiar
home range and social environments
that individuals experienced pre-
clearing. The cleared environment
is therefore inimical to the survival
of mammals. Some species such
as large kangaroos make use of
open pastures, but still need some
remnants of scrubbier vegetation
for shelter.
If mammals cannot survive in
a newly-cleared environment,
can they survive if they move to
uncleared areas of vegetation?
The answer is ‘no’, for several
reasons. Firstly, except for some
desert-dwelling species most native
mammals are sedentary, and many
will even ‘home’ back to a familiar
location if they are displaced.
2. MAMMALS
17
Impacts of Land Clearing
WWF-Australia
Secondly, uncleared areas of
vegetation will be occupied by
resident animals. In the
short-term, residents will often
repel intruders and prevent them
from relocating. In the longer
term, if displaced individuals
do settle, they will increase
demands on scarce resources in
the reduced areas of uncleared
land, and population numbers
in the fragments will decline.
Thirdly, even if unoccupied land
is available, there is no guarantee
that it will be suitable for displaced
individuals to use. For example,
Tyndale-Biscoe and Smith
experimentally removed greater
gliders (Petauroides volans) from
a block of forest and then waited to
see if gliders from a logged block
next to it would use it.36 They
did not; animals moved in at the
same very low level as they did
into fully occupied forest. Finally,
a serious problem for mammals
displaced by vegetation clearing is
that they face a very high risk of
being taken by predators such as
red foxes (Vulpes vulpes), feral
cats (Felis catus) and dogs (Canis
lupus familiaris). For example,
a study of ringtail possums
(Pseudocheirus peregrinus)
released experimentally into
Ku-ring-gai Chase National Park,
near Sydney, Augee et al. (1996)
found that 110 of 118 animals
whose fates they could determine
were killed by predators. The
impacts of predators on displaced
mammals have been documented
in several studies.37
2.5
FUTURE OF
MAMMALS IN
NEW SOUTH
WALES
As well as Australia having the
world’s highest extinction rate
for native mammals in the last
200 years, a further 83 terrestrial
species and subspecies are
currently listed as being at risk
of extinction.38 Within Australia,
NSW has a particularly poor
conservation record for its
mammals, with the worst-affected
regions lying west of the Great
Dividing Range39. These regions
are where much vegetation clearing
now occurs. Clearing of vegetation
and subsequent land uses such as
grazing and cropping have been
identified previously as major
threats for mammals in these
regions.40 Looking to the year
2038, Dickman constructed three
scenarios for NSW mammals.41
The first scenario predicted
increased mammalian diversity due
to discoveries in fauna surveys and
research, and the second foresaw
no change. In both scenarios, no
further extinctions were envisaged.
In the third scenario, land clearing
and other threatening processes
were seen as continuing without
check, and reducing the State’s
mammal fauna from its original
130 species to just 53 species by
2038. The destruction of some
60% of the State’s native mammals
would be unprecedented on a world
scale. Continued land clearing has
the potential to push us closer to
this apocalyptic scenario.
Within Australia, NSW has a particularly poor
conservation record for its mammals, with the
worst-affected regions lying west of the Great
Dividing Range
© WWF / Frédy MERCAY
1
GREATER GLIDER
(PETAUROIDES
VOLANS)
Occurring broadly in
forest and woodland in
eastern Australia, this large gliding
possum depends on hollows in old
trees for shelter and specialises in
eating the leaves of a small number
of Eucalyptus species. During
clearing operations animals may
escape being crushed by gliding
as trees fall. In a detailed study by
Tyndale-Biscoe and Smith45, near
Canberra, the authors captured
and marked every glider that
escaped tree fall. Although the
study extended for five years, more
than three quarters of the marked
gliders were never seen again after
being marked. Of the few survivors,
almost three quarters were
recaptured within eight days of tree
clearing; these had lost weight and
the females had lost their pouch
young. The very few animals that
survived to the following year
typically had home ranges that
overlapped a block of forest that
had not been felled. Is
it possible that the animals that
disappeared had simply moved
somewhere else? In this particular
study the cleared forest was mostly
surrounded by pine plantations
and open farm land where gliders
cannot live. Searches for marked
animals failed to find any there.
Greater gliders are typically
sedentary and are reluctant to
move even if unoccupied forest is
available.
The authors concluded that, while
few greater gliders are killed during
tree fall, over 90% remain in their
destroyed home range and die
soon after. The immediate causes
of death are not known, but most
likely include starvation, exposure
and predation. Some animals
can survive, but only if at least
part of their home range remains
uncleared.
2.6 CASE STUDIES:
THE EFFECTS
OF CLEARING
ON POSSUMS
AND GLIDERS
Surveys in recent years have shown that over
300 species of native vertebrates use tree
hollows for shelter, with 83 of these species
(31%) being mammals.42 Many more species
use trees and shrubs as arenas for social
interactions, to move about in the canopy,
to escape predators and other enemies on
the ground, to search for insects and other
foods, or to eat the leaves, buds and flowers
on the plants directly.43 For slow-moving
species, such as koalas and possums, we
can expect many individuals to be killed
by the trauma of tree fall or by associated
injuries sustained in the clearing operation.44
If animals do survive the process of clearing,
what prospects do they have afterwards?
Quantitative information from two case
studies of possums and gliders shows that
most will die.
18 Impacts of Land Clearing
WWF-Australia
19
Impacts of Land Clearing
WWF-Australia
2EASTERN
PYGMY-POSSUM
(CERCARTETUS
NANUS)
This diminutive possum
lives in forest and heath-dominated
habitats in south-eastern Australia,
and visits flowers to obtain nectar,
pollen and occasional insects. It
is listed as a vulnerable species in
NSW. In the Dorrigo region on the
New England Tablelands, eastern
pygmy-possums can sometimes
be found in scattered remnants
of forest that has otherwise been
cleared for cattle grazing. Studies
of this species in a small
(4 hectare) remnant by Bladon
et al46 found that possums took
readily to nest boxes that were
placed in trees, and used them
to rear their young. Eighteen
months after the studies began, a
substantial portion of the remnant
(1.4 hectares, 35%) was cleared
without warning by the land’s new
owner. Although two-thirds of the
original habitat remained, monthly
capture rates of pygmy-possums
fell from 33.5% to just 7.8%, and
the population from 15-20 animals
to only 5-8. In percentage terms,
these population reductions were
much greater than might have
been expected from the loss of
habitat. The authors concluded that
the population crash was due to
immediate losses of possums (i.e.,
deaths), loss of habitat, and time
taken for surviving pygmy-possums
to relocate and begin using nest
boxes again. There was no evidence
that the missing possums had
relocated elsewhere. Apart from
being surrounded by open pasture,
no marked animals were found in
other forest remnants around the
disrupted one, despite intensive
searching.
There were two other unexpected
findings in this study. Firstly, the
effects of the clearing appeared
to be much greater on females
than on males. Prior to clearing
females comprised about 60%
of the adult animals in the
population, but in the six months
post-clearing the sex ratio fell so
dramatically that just one animal
out of every five captured was
female. Secondly, females that had
been carrying young before the
clearing event were not seen again,
and recruitment of young to the
population over the breeding season
was zero. These results suggest that
even partial clearing can have large
and disproportionately negative
effects on pygmy-possums and
(to quote the authors) “support
concerns that the long-term survival
of the eastern pygmy-possum in
New South Wales is threatened by
continued land clearing throughout
much of its present range.”
© Viewfinder
20 Impacts of Land Clearing
WWF-Australia
3.1
OVERVIEW
Some 450 species of birds regularly occur in NSW and about half of
these may be found in the eucalypt forests and woodlands of the Great
Dividing Range, western slopes and plains. Some 115 species of birds
(i. e. about 25%) in NSW are considered to be threatened with extinction
in the State. Twenty seven of these threatened species may be found in the
woodlands and open forests west of the Great Dividing Range, that is in
the habitats that have been most extensively cleared in the last 10 years.
Most significantly, the loss and fragmentation of habitat, due to clearing,
has been listed as a key threatening process for all of these species. Many
of these birds are characteristic of the western slopes woodlands, such
as the endangered regent honeyeater (Xanthomyza phrygia), swift parrot
(Lathamus discolor) and black-throated finch (Peophila cincta). The box-
ironbark forests of the slopes are also the major habitats for vulnerable
species such as the grey-crowned babbler (Pomatostomus temporalis),
diamond firetail (Staganopleura guttata) and black-chinned honeyeater
(Melithreptus gularis).47
In addition to these threatened species there is accumulating evidence
that many other birds of the inland woodlands and forests are declining
and disappearing locally. A continuation of broad-scale clearing of native
vegetation will mean that they may soon join the list of threatened species
in the State.
3.2
NUMBER OF BIRDS KILLED BY
NATIVE VEGETATION LOSS IN NSW
• Some 13 million native birds died or will die in
NSW as a result of the clearing of native vegetation
approved between 1998 and 2005.
It is conservatively estimated that around 13 million birds have died or will
die as a result of the clearing of native vegetation approved between 1998
and 2005.
As noted previously, this estimate does not include the number of birds
killed by illegal or exempt clearing. For example, over half a million birds
would have been killed by illegal clearing in 2005 as estimated by the
Auditor-General.
Although the birds that have died or will die will of course include
numerous common species, such as noisy miners (Manorina
melanocephala) and striated pardalotes (Pardalotus striatus), they
will include a number of species that are threatened in NSW such as
regent honeyeaters (Xanthomyza phrygia) and grey-crowned babblers
(Pomatostomus temporalis). Furthermore, an increasing number of
woodland birds in NSW are known to be declining, with a likelihood
that they will become threatened in the near future, if current threatening
processes, such as loss of their habitat, continues.
3. BIRDS
21
Impacts of Land Clearing
WWF-Australia
It is conservatively estimated that around
13 million birds have died or will die as a result
of the clearing of native vegetation approved
between 1998 and 2005.
© Andrew Cochran/ Taronga Zoo
22 Impacts of Land Clearing
WWF-Australia
3.3
HOW HAVE
THESE
NUMBERS
BEEN
ESTIMATED?
The estimates have been calculated
by multiplying a mean value
for bird density by the number
of hectares known to have been
approved for clearing by the NSW
Government.48
Birds occur at different densities in
different natural habitats, reaching
their highest densities in wet
forests and their lowest densities
in grassland. The available
evidence suggests that most recent
clearing has been in the Barwon
and central west regions of NSW
and the eastern parts of the far
west. Broadly, this consists of
woodland and parkland. In actual
fact, vegetation in this region
ranges from open eucalypt forests
and woodlands, as well as open
forest and woodland with varying
amounts of Callitris pine and
Casuarina, plus small areas that
are dominated by Acacia. Some
woodlands, for instance those
with poplar box (E. populnea)
contain quite low densities of
trees. Generally, birds become less
abundant as the density of trees
and shrubs declines. Consequently,
studies have been sought that
estimate the densities of birds in
a range of vegetation types that
occur in the region of NSW where
clearing has been most prevalent.
Table 4 lists the results from a
range of locations, mostly in
NSW, where bird densities have
been estimated. These range from
the Tablelands to the eastern part
of the Western Plains, and from
south of the Murray in Victoria to
central Queensland. They include
all of the major vegetation types
in the region, from woodland to
forest, and dominated by gums,
boxes, stringybarks and ironbarks
(Eucalyptus), as well as Callitris
and Casuarina. The density of
birds in these sites range from
under 10/ha in degraded woodlands
in Victoria, poplar box woodland
and tablelands woodland after a
severe drought, to over 30/ha in
white box (E. albens) remnants
and mixed open forest with many
ironbarks near Bundarra. The
overall mean value is 20.7 birds/ha.
Therefore some 13 million
woodland and forest birds have
been or will be affected by the
clearing of all vegetation that
had been approved by the NSW
Government from 1998 to 2005
(640,000 x 20.7 = 13,250,000).
The following table lists the results
of estimates of bird densities from
a range of locations.
3. BIRDS
© Klein Hubert
23
Impacts of Land Clearing
WWF-Australia
Habitat Region Density - Birds/ha Reference Notes
Coastal and Range
Forests
Mean = 30.4
Open forest and woodland SE Queensland 9.9 summer, 25.5 winter Catterall et al. 199849
Dry sclerophyll forest Coastal NSW 23.6-51.3 Milledge and Recher 198550
Wet sclerophyll forest Coastal NSW 36.8-54.1 Milledge and Recher 198551
Dry sclerophyll forest Coastal NSW 31.5 Shields et al. 1985 52
Wet sclerophyll forest Coastal NSW 25.9-35.5. Shields et al. 1985 53
Open forest Sydney 23.3 Keast 1985 54
Silvertop ash, stringybark Eden 25.6 Kavanagh and Stanton
2003
Unlogged sites only
Tableland Woodlands Mean = 19.5
Stringybark woodland New England 21.5-23.6 Ford and Bell 1982 55 Large remnant
Stringybark woodland New England 9.7 Ford et al. 1985 56 Same as above but
after severe drought
Stringybark, gum, box
woodland/ open forest
New England 18.2 breeding, 32.5 winter Howe 1984 57 Continuous forest
Stringybark, gum, box
woodland/ open forest
New England 16.1 breeding, 16.6 winter Howe 1984 58 Remnants
Tablelands woodland S NSW 16.4-20 Recher and Holmes 198559
Tablelands open forest S NSW 15-27.6 Recher and Holmes 1985 60
Blakely’s red gum, yellow
box
ACT 22.8 Er and Tidemann 1996
Slopes Woodland and
Open Forest
Mean = 35.1
Open forest NW Slopes of NSW 42.8 Oliver et al. 1999 61
Box, stringybark, gum, pine Pilliga Scrub 25.9 Date, pers comm
White box woodland Gunnedah 36.6 Martin et al. 2004
Plains Woodland and
Scrub
Mean = 13.8
Box, gum, pine woodlands Northern Plains, Victoria 8.2 Antos and Bennett 2004
Box, gum, pine Murray Plains 19.7 Oliver and Parker 2006 Mature only – excl.
replanted
Eucalypt woodland,
brigalow
Emerald, Queensland 21.7 Woinarski et al. 2006 Average of 1973-6
and 2001-2 counts
Poplar box Central Queensland 9.2 Gilmore 1985 62 Number of pairs x 4
Gidgee Central Queensland 10.2 Gilmore 1985 63 Number of pairs x 4
Grassland Mean = 1.3
Grassland New England 0.8 Ford and Bell 1982 64 Native grassland,
scattered trees
Grassland New England 1.9 Barrett 1995 65 Native or Exotic
Pasture, Scattered
Trees
Rainforest Mean = 33.0
Rainforest Coastal NSW 33.0 Shields et al. 1985 66
Table 4: Estimates of the density of birds from a variety of habitats.
24 Impacts of Land Clearing
WWF-Australia
3.4
WHAT
HAPPENS TO
BIRDS WHEN
THEIR HABITAT
IS CLEARED?
Somewhat surprisingly, there
seem to have been few studies on
the direct impact of vegetation
clearance on birds. Birds are
considerably more mobile than
most mammals and reptiles, and
many will survive the immediate
clearing and even the burning
of wind-rowed vegetation. Eggs
and nestlings, and most recently
fledged young will probably die
immediately. Ludwig et al. (2000)67
studied the impact of clearing
of eucalypt woodlands near
Emerald in central Queensland.
Four of the six most common bird
species were significantly less
common in cleared land, and a
fifth probably was also negatively
affected by clearing. Only the
red-backed fairy-wren (Malurus
melanocephalus) increased in
cleared sites, because it prefers
dense grassy habitat. Fulton and
Majer (2006)68 looked at the effect
of chaining of Allocasuarina
shrubland in the Western Australian
Wheatbelt. They compared sites
in uncleared shrubland, in chained
but unburnt shrubland and in dead
stubble. Again, most woodland
birds declined or disappeared
after chaining, including two
species that are regarded as near
threatened, the crested bellbird
(Oreoica guttaralis) and the white-
browed babbler (Pomatostomus
superciliosus). A few species
became more common in the
chained site or stubble, for example
the willy wagtail (Rhipidura
leucophrys), and the Richard’s pipit
(Anthus novaeseelandiae) which
only moved in after chaining.
The longer term effects of clearing
or chaining of woodland, burning
of the debris and conversion to
pasture of crops can be seen from
examining birds in grassland (Table
4). There are typically only one
or two birds per ha in grassland,
i. e. 90-95% fewer than in intact
woodland. It should also be noted
that these are mostly not woodland
species, such as the pipit.
Therefore, it is reasonable to
conclude that almost all woodland
birds either die or leave the
area after it has been cleared,
though some may stay for some
time. We can only surmise what
happens to birds that leave when
their home ranges are destroyed.
Those that survive may move
into neighbouring habitat or cross
open areas to other remnants. This
may put them at greater risk of
predation (see section 3.4). If they
reach suitable habitat this is likely
to be occupied by, and defended
by, other members of the same
species. More likely, they will
have to settle for inferior habitat.
Although they may survive here
for some time, they are unlikely
to breed successfully and replace
themselves before they die. This
could be because safe nest sites
such as tree hollows or dense
shrubs are lacking or because
predators are more common. Also,
important foraging sites or foods,
such as large tree trunks and nectar
may be scarce. Consequently, even
though clearing may not kill the
majority of the woodland birds
directly, over the longer term they
will be lost from the landscape.
3.5
FUTURE
IMPACTS OF
CLEARING
OF NATIVE
VEGETATION
ON BIRD
POPULATIONS
Whereas, there may be a direct
decline in the populations of
woodland birds due to loss of their
habitat, what is now becoming
clear is that for many species the
decline in these populations is
actually far greater than simply the
proportion of habitat that has been
lost.69 Clearing of native vegetation,
especially in those regions where
only a small proportion is left,
will lead to remnants that are
smaller, and more isolated from
each other, and also, because they
have more edge are likely to be
more degraded than continuous
woodland. Many woodland birds
avoid, or soon disappear from,
smaller patches. Furthermore, they
may be unwilling to disperse to
isolated remnants. Most species
are absent from sites smaller than
3. BIRDS
25
Impacts of Land Clearing
WWF-Australia
10 ha, but also quite a few species
tend to be less frequent in sites
less than 100 ha in area. There
are many reasons for this, and
they interact in complex ways.
As well as the chance loss of
small populations and difficulties
experienced in dispersing, birds in
highly fragmented and degraded
landscapes may suffer higher rates
of predation, especially on their
nests, and also competition from
aggressive species, such as noisy
miners. We perhaps know best
what is happening in the case of the
robins (see case study).
Taken overall, the impact of
clearing and loss of a substantial
proportion of the native vegetation
may lead to the decline of many
woodland birds, and even the
regional extinction of some
species. This is most evident when
only about 10% of the native
vegetation remains. This is the
case in the Mount Lofty Ranges of
South Australia, where the long-
term effects of extensive clearing
over a century ago are still being
felt. As a result, as many as 50
of the 120 native bird species are
predicted to eventually disappear as
a result of the reduction of habitat
area to ten per cent of its former
extent.70 The impact of removing
90% of the native vegetation is
also clear in the Western Australian
Wheatbelt, and parts of Victoria.
Within NSW, critical levels of
habitat loss have been reached on
parts of the Tablelands. Although
we may not yet have reached these
critical levels throughout parts of
the western slopes and adjoining
plains, if we continue to clear at
current rates, we shall soon reach
the point at which many bird
populations move into regional
decline and extinction. It is
imperative that we limit the amount
of clearing of native vegetation
in NSW to prevent any further
declines and extinctions of our
native birds. Unless we do this, any
efforts to revegetate will be in vain.
It is reasonable to conclude that almost all
woodland birds either die or leave the area after
it has been cleared, though some may stay for
some time.
© WWF-Canon, Martin HARVEY
3.6 CASE STUDY:
WHAT IS
HAPPENING
TO ROBINS?
Robins are a brightly coloured
group of birds with two or three
species often found in most
wooded areas. They have been the
subject of many studies and these
together provide a clear indication
of how the loss, fragmentation
and degradation of habitat can
affect our woodland birds. Birds
Australia conducted its second
bird atlas from 1998 to 2002,
some 20 years after the first atlas
was completed.71 The atlases have
provided one of the few sources of
quantitative information on how
the abundance of some woodland
birds has changed. The robins
have fared worse than most, with
several species showing a decline
in detection rate of 40% or more in
NSW (Table 5).
Studies in Western Australia,
Victoria and NSW have
documented the loss of hooded
and yellow robins from vegetation
remnants. The Armidale area
provides an excellent example.
Hooded robins had gone from
three patches in the early 1980s,
and from three more by 2006.
Eastern yellow robins in this time
had vanished from two patches.
Although these are probably
random losses of very small
populations – often single pairs,
what is worrying is that they are
not rescued by immigrants from
other patches.
So, are robins unable or unwilling
to disperse among isolated patches?
Debus72 moved eastern yellow
robins to one patch, which had
lost the species in the early 1990s.
Some of the birds stayed and even
bred successfully, suggesting that
the habitat was satisfactory for
them, but that they had not been
able to reach it. However, two birds
travelled 7 km to the reintroduction
site from another patch unaided.
So yellow robins can move
between remnants. Scarlet robins
also arrived in another site every
spring, probably from over 10 km
away. Further translocations have
provided less clear-cut results.
Few birds stayed in their new
locations for long, and in fact,
several translocated birds were
killed by predators, probably
grey butcherbirds (Cracticus
torquatus). So robins can disperse,
but it is a risky exercise, and
perhaps they often choose not to
cross cleared country.
Whether or not robins can disperse
among vegetation remnants may
be irrelevant if there are too few
young birds available to disperse.
Debus found that young fledged
from only about 9% of scarlet
robin nests in one woodland
remnant, a figure very similar to
that found by Robinson in more
continuous woodland in southern
NSW.73 Yellow robins were more
than twice as successful, but even
so they barely produced enough
young to replace local deaths,
let alone provide new dispersers.
Scarlet robins only maintained
themselves due to the immigrants.
The main nest predators were pied
currawongs (Strepera graculina),
which have increased due to the
winter supply of exotic berries.
However, there are plenty of other
nest predators from possums to
shrike-thrushes and kookaburras.
Even if they manage to escape
nest predators, robins may still
struggle to feed their babies.
Zanette found that there are fewer
ground invertebrates in some
smaller remnants, and chicks and
incubating females were fed less
often in such sites.74 Fertilised soils
also may mean denser grass cover,
which can make capture of food
difficult for the pouncing robins.
Robins even in extensive eucalypt
woodlands are found in much
lower densities than in rainforest.
This is probably due to lower food
abundance, most likely due to the
scarcity of leaf litter and perhaps
because there is less fallen timber.
To some extent this is natural, and
to some extent because people have
collected firewood.
So, robins are affected by a host of
problems as they struggle to survive
in their highly modified landscapes.
Quite likely other birds, which
have not been studied as well, are
influenced in the same way.
It is noted that for almost all species
the decline has been greater in NSW
than in Australia as a whole.
Species Decline in
Australia
Decline in
NSW
Flame robin 51% 56%
Scarlet robin 31% 55%
Hooded robin 27% 41%
Jacky winter 19% 21%
Crested shrike-tit 25% 18%
Dusky woodswallow 28% 41%
White-browed woodswallow 38% 61%
Black-faced woodswallow 36% 65%
Masked woodswallow 22% 46%
Bush stone curlew 63%
Table 5. Declines in recording rates of robins, and some other
woodland birds, in Australia and NSW, between the first and
second bird atlas. 75
26 Impacts of Land Clearing
WWF-Australia
© John Courtney
28 Impacts of Land Clearing
WWF-Australia
4.1
OVERVIEW
About 830 species of non-marine
reptiles are found in Australia - of
these, 227 (27%) occur in NSW.
4.2
NUMBER OF
REPTILES
KILLED BY
THE CLEARING
OF NATIVE
VEGETATION
• 80 million reptiles died
or will die in NSW as
a result of the clearing
of native vegetation
approved between
1998 and 2005.
It is conservatively estimated
that more than 80 million reptiles
have died or will die as a result of
the clearing of native vegetation
approved in NSW between 1998
and 2005. In 2005 alone, it is
estimated that at least 9.7 million
reptiles perished.
However, the actual mortality is
likely to be much higher because a
conservative population density has
been used.
Furthermore, as noted previously,
this estimate does not include the
number of reptiles killed by illegal
or exempt clearing. For example,
the level of illegal clearing
estimated by the Auditor-General
to have occurred in 2005 would
have resulted in the deaths of more
than 3 million reptiles.
In NSW the highest numbers
of reptile species are found in
the moister forests of the coast
and ranges. This region suffered
high levels of clearing of native
forest in the nineteenth and
early twentieth centuries, so that
current clearing rates represent a
relatively small proportion of the
total native vegetation clearing
being undertaken in NSW at the
present time. Consequently, though
estimates of the number of reptiles
perishing as a result of native land
clearing in the State have been
estimated for all of NSW, the
highest annual levels of clearing,
and thus the greatest numbers of
reptile deaths, are occurring in the
approximately three quarters of
NSW extending from the western
slopes of the Great Dividing Range
4. REPTILES
© Digital Stock
29
Impacts of Land Clearing
WWF-Australia
4.3
HOW HAVE
THESE
NUMBERS
BEEN
ESTIMATED?
In the absence of any reliable
studies of the total numbers of all
reptiles occurring in any given
site in Australia, estimates were
made by modifying the method
developed by Ehmann & Cogger76,
in which they concluded that,
on average across Australia, the
density of reptiles in any given
area was about 200/ha, based on
the average presence of about
20 species with a mean density per
species of 10 individuals/ha.
However, because an Australia-
wide estimate must take into
account large areas of reptile-rich
desert lands and those of the wet
and seasonally-wet tropics, this
approach has been modified here
to take into account the known
distributions of NSW reptiles
across various vegetation zones and
to estimate the number of species
occurring in each zone.
First, each of the major plant
associations found in NSW
and their original geographic
distributions were extracted from
a vegetation map in which the
17 vegetation associations defined
by Williams77 that occurred in
NSW were later aggregated by
Williams78 into nine broader
associations. The approximate
areas in which each of these plant
associations occur within NSW
were estimated, together with the
total number of species of reptiles
occurring in each association
(Table 6).
The resulting species-richness
numbers were then weighted to take
into account the total areas of each
zone in order to arrive at a mean
species richness per zone, with the
further assumption made (based on
qualitative observations) that in any
given hectare of any zone, at least
25% of the species found in that
zone are likely to be present.
Vegetation Association Area of potential
occurrence (ha approx)
Reptilian Species Richness Area x richness weighting
1. Rainforest 1,200,000 33 39,600,000
2. Evergreen sclerophyll forest 14,500,000 124 1798,000,000
3. Woodland & parkland 31,600,000 116 3665,600,000
4. Grassland & savannah 3,000,000 64 192,000,000
5. Malee Scrub & heath 3,300,000 58 191,400,000
6. Mulga & other arid scrub 20,200,000 100 2020,000,000
7.
S
altbush & other shrub steppe 7,500,000 71 532,500,000
8. Semi-desert steppe 200,000 56 11,200,000
Total 81,500,000 622 8,450,300,000
Mean 10,187,500 77.75 1,056,287,500
Mean species richness = 77.5
Mean weighted species richness/vegetation type (mean area richness weighting/mean area of potential occurence) = 103.7
Mean weighted species richness/ha = 25.9
Table 6: Major vegetation associations in NSW and the number of species of reptiles recorded from each association
It is conservatively estimated that more than
80 million reptiles have died or will die as
a result of the clearing of native vegetation
approved in NSW between 1998 and 2005.
30 Impacts of Land Clearing
WWF-Australia
4.3
HOW HAVE THESE NUMBERS
BEEN ESTIMATED?
Continued
Finally, to take into account the lower productivity of NSW’s temperate
climatic zone, the mean individual species density/ha was reduced from
1079 to 5. This reduction is arbitrary, but is intended to demonstrate that
when using a very conservative estimate, the deaths of large numbers of
reptiles have resulted from the clearing of native vegetation in NSW during
the past decade (Table 7).
4. REPTILES
Table 7: Estimates of reptile mortalities resulting from the approved
clearing of native vegetation in NSW, 1998-2005. Clearing rates,
to the nearest thousand, are those recorded by the NSW Auditor-
General.80 Mortality numbers were calculated using the formula
N= total area cleared (ha) x mean species richness (25.9) x mean
individual species density (5)
Year Approved clearing (ha) Reptile mortality
2005 45,000 5,827,500
2004 74,000 9,583,000
2003 64,000 8,000,000
2002 58,000 7,511,000
2001 91,000 11,784,500
2000 74,000 9,583,000
1999 161,000 20,849,500
1998 74,000 9,583,000
Total 641,000 82,721,500
4.4
WHAT
HAPPENS TO
REPTILES
WHEN THEIR
HABITAT IS
CLEARED?
It is commonly, but erroneously,
believed that reptiles (and many
other animals) displaced by
clearing native vegetation will
simply ‘move on’ to the next
available patch of suitable habitat.
However, reptiles are surprisingly
sedentary. Smaller lizards such
as many skinks, geckos and
dragons usually have home ranges
measured in the hundreds of
square metres or less. Even many
snakes and larger lizards have
similarly small home ranges and
it is only individuals of some of
the larger goannas, snakes,
turtles and crocodiles that may
range over many hectares or even
square kilometres.
Following clearing of native
vegetation, crossing areas of hostile
habitat to reach other patches of
suitable vegetation is therefore
not an option for most reptiles.
Few would attempt it and those
that did will quickly die from
predation or exposure to unsuitable
climatic conditions.
And so, unlike birds (and other
flying organisms), the vast majority
of reptiles whose habitats are
disturbed by clearing of native
vegetation have nowhere to go
unless the area cleared is part of
a larger, continuous patch. In this
case, some of the displaced reptiles
may be able to make their way into
the remaining remnant.
However, if the area being cleared
is an isolated patch that has no
direct link - a habitat corridor
– to other patches of the same
habitat, the majority of reptiles will
simply die or be eaten immediately
after clearing has occurred. The
exceptions are those few species
that might have been exploiting
disturbed sites in the original
habitat (road, track and stream
edges, patches of invasive weeds,
clearings caused by humans or
tree falls) and which may not
only survive but also thrive in the
remaining habitat. If the clearing is
undertaken in stages, some species
may survive for a time in windrows
prior to burning, but their reprieve
is likely to be temporary.
31
Impacts of Land Clearing
WWF-Australia
Further, it is often argued that
biodiversity loss resulting
from native vegetation clearing
is a reversible process – that
natural regeneration or active
rehabilitation by humans can
result in recolonisation by those
species that constituted the original
biodiversity of an area. In reality
it is nearly always only a smaller
subset of the original species that
can successfully recolonise the area,
and then only if the rehabilitated
vegetation is continuous with an
intact, uncleared area of the original
habitat. The latter is essential as a
source of recruitment of the species
originally present. Consequently, the
clearing of any isolated remnants
of native vegetation permanently
reduces or eliminates most of their
reptile fauna.
Thus, for the great majority (ca.
90%) of native reptiles clearing is
a death sentence. Even for those
individuals that can make their
way to adjacent areas of suitable
habitat, the carrying capacity of
that habitat is more or less stable
and relatively inflexible. Despite
seasonal variations in its carrying
capacity (for example, as a result
of flowering events or drought),
it can rarely accommodate a new
wave of consuming migrants
without serious impacts on its
ecological integrity. Therefore new
immigrants, if they survive, will
do so at the expense of existing
residents. The net effect will be the
deaths of old and new residents
roughly equivalent to the numbers
migrating from the original
clearing event. Those individuals
that fail to migrate to nearby
suitable habitat will die.
4.5
THE FUTURE
OF REPTILES
The majority of reptiles are
declining in numbers, but those
at the greatest risk of extinction
are those whose declines are
driven largely by the loss of native
vegetation and the consequent
fragmentation of their populations.
© Klein & Hubert
4.6 CASE STUDY:
MALLEE/
SPINIFEX – A CASE STUDY
IN PERMANENT LOSS OF SPECIES
FOLLOWING CLEARING
Reptile Species Regional
Generalist
Regional
Specialist
Exploits
disturbed
(post-clearing)
habitats
Byrne’s gecko
(Diplodactylus byrnei)
Southern spiny-tailed
gecko (Strophurus
intermedius)
Eastern stone gecko
(Diplodactylus vittatus)
Beaded gecko
(Lucasium damaeum)
Beaked gecko
(Rhynchoedura ornata)
Dtella (Gehyra variegata)• •
Thick-tailed gecko
(Underwoodisaurus milii)
Unpatterned delma
(Delma inornata)
Burton’s snake-lizard
(Lialis burtonis)
Eastern hooded scaly-
foot (Pygopus schraderi)
Common scaly-foot
(Pygopus lepidopodus)
Nobbi (Amphibolurus nobbi)
Table 8: The reptile species permanently extirpated from native mallee/spinifex plant communities following clearing for cereal production
– vicinity of Round Hill Nature Reserve, NSW.
Reptile Species Regional
Generalist
Regional
Specialist
Exploits
disturbed
(post-clearing)
habitats
Mallee dragon
(Ctenophorus fordi)
*
Painted dragon
(Ctenophorus pictus)
Central bearded dragon
(Pogona vitticeps)
• •
Gould’s goanna
(Varanus gouldii)
• •
Lace monitor
(Varanus varius)
• •
Carnaby’s snake-eyed
skink (Cryptoblepharus
carnabyi)
• •
Ctenotus allotropis
Ctenotus atlas
Robust ctenotus
(Ctenotus robustus)
Schomburg’s ctenotus
(Ctenotus schomburgkii)
Desert skink (Egernia
inornata)
Tree skink (Egernia
striolata)
• •
Mueller’s lerista (Lerista
muelleri)
Spotted lerista (Lerista
punctatovittata)
Gray’s four-toed skink
(Menetia greyi)
Boulenger’s morethia
(Morethia boulengeri)
• •
In a long-term study commenced in 196781 and monitored periodically
to the present, Cogger studied trends in a population of mallee dragons
(Ctenophorus fordi) at Round Hill Nature Reserve in mid-western NSW,
an area dominated by a rich mallee/spinifex plant community.82 Other
species of reptiles were concurrently recorded within the reserve and,
more intensively, in the 3 hectares study plot. Over this same period, large
tracts of mallee on adjacent private lands were cleared (mostly for cereal
production) and provided an opportunity to study the effects of clearing on
the original reptilian residents of the cleared land.
Impacts of Land Clearing
WWF-Australia
32
33
Impacts of Land Clearing
WWF-Australia
Table 8: The reptile species permanently extirpated from native mallee/spinifex plant communities following clearing for cereal production
– vicinity of Round Hill Nature Reserve, NSW.
Reptile Species Regional
Generalist
Regional
Specialist
Exploits
disturbed
(post-clearing)
habitats
Dull morethia
(Morethia obscura)
Western blue-tongue
(Tiliqua occipitalis)
Eastern blue-tongue
(Tiliqua scincoides)
• •
Shingleback (Tiliqua rugosa)
• •
Southern blind snake
(Ramphotyphlops australis)
*
Prong-snouted blind
snake (Ramphotyphlops
bituberculatus)
Carpet python
(Morelia spilota)
Western brown snake
(Pseudonaja nuchalis)
• •
Coral snake
(Simoselaps australis)
Dwyer’s black-headed
snake (Parasuta dwyeri)
Bandy-bandy
(Vermicella annulata)
Of the 39 reptile species recorded
from the reserve (Table 8), 7 (18%)
are essentially mallee specialists
that were not or rarely encountered
outside intact mallee/Triodia
habitats within the region. A
further 32 species were regional
generalists in that they also
occurred in a range of vegetation
associations – Callitris and other
native parklands and woodlands,
and in rocky outcrops, stony hills
and lightly-wooded grazing lands
within the region.
Only 10 species – generally
snakes and larger lizards such
as the western brown snake
(Pseudonaja nuchalis), shingle-
back lizard (Tiliqua rugosus) and
Gould’s goanna (Varanus gouldii)
– readily exploited cleared land
and regrowth. Some of the arboreal
generalists – for example the
Dtella (Gehyra variegata) and
the tree skink (Egernia striolata)
- continued to occupy isolated trees
and copses left after clearing has
occurred. This group represented
26% of the species present in the
undisturbed mallee.
But for the majority of species
in this study, clearing resulted in
their permanent extirpation from
the areas in which they originally
occurred. Twenty-nine species
(74% of the 39 species found in the
intact mallee/spinifex community)
were lost. Using the conservative
calculation shown above/below
(assigning a mean density per
species of 10 individuals/ha)
indicates that at this study site
at least 290 reptiles are killed
for every hectare cleared for
commercial production, and that
the ‘standing crop’ or biomass
of each of these native species is
not only permanently reduced,
but the ecosystem services and
productivity of the cleared land are
also permanently compromised.
Accurate figures on past and
recent mallee clearing rates in
NSW are unavailable, although
the Australian Natural Resources
Atlas83 estimates that of the
36,746 km2 of mallee woodlands
and shrublands present in pre-
European NSW, 92% (33,889
km2) remained uncleared in 1997.
Yet in 1974 Specht et al. (basing
their calculations on Williams’
1955 vegetation map of Australia)
estimated the area of semi-
arid mallee in NSW as 25,000
km84. These differences reflect
differences in both the vegetation
classifications used over time
and the unreliability of available
estimates of mallee distribution
and clearing rates.
This case study is not intended
to imply that no mallee should
ever have been cleared, or should
not be cleared in the future, for
commercial production. Rather,
it is argued that the long-term
impacts of clearing of any native
vegetation can vary widely in its
impacts on regional and national
biodiversity. Such clearing should
be part of a well-developed
regional plan that aims to optimise
the retention of viable wildlife
corridors and to set aside other
areas for sustainable biodiversity
conservation. In other words, every
hectare of surviving mallee is not
of equal value for biodiversity
conservation purposes. Cairnes
(1989) suggested a set of land
use planning policies for mallee
ecosystems in NSW that could as
well serve as a guide for all native
ecosystems.85
However policies to date, even
when developed and implemented
through legislation, have been
shown by the NSW Auditor-
General86 to fail miserably unless
the Government of the day is
prepared to rigorously police its
own legislation.
Species present = 39
Mallee specialists = 7 (18%)
Regional generalists
(found in a range of regional vegetation associations) = 32 (82%)
Exploiters of post-clearing habitats = 10 (26%)
34 Impacts of Land Clearing
WWF-Australia
WWF called on a team of
specialists to provide this estimate
of the impact of the rates of
clearing of native vegetation in
NSW on mammals, birds and
reptiles approved between 1998
and 2005 inclusively. The figures
are clearly dire and show that the
long-term impacts of clearing
native vegetation are disastrous
for wildlife in NSW.
More than 104 million native
mammals, birds and reptiles have
died or will die as a result of
the clearing of native vegetation
approved by the NSW government
between 1998 and 2005.
Despite a decade of native
vegetation legislation, NSW has
implemented no Statewide system
of monitoring changes to its
vegetation, recording the amount
of vegetation being lost or even
comprehensively classifying its
vegetation types.
These impacts are additional to the
many millions of native animals
that have died or will die as a
result of other clearing activities
in NSW, such as illegal clearing
and exempt clearing during this
period. Furthermore, enormous
loss of native wildlife has occurred
in NSW as a result of the clearing
of native vegetation prior to 1998
and since European settlement. For
example, figures for the previous
decade 1988-1998 suggest that
annual native vegetation clearing
rates have long been substantial,
though variable, and of a similar
order to those that occurred in the
period 1998-2005.
In addition, the full impact of
NSW’s past land clearing on
native animal populations is still
to be felt. The native vegetation
already lost in NSW has created an
extinction debt that is yet to be paid
and has set in train a process of
regional and ultimately Statewide
extinctions of entire populations.
5. CONCLUSION
©WWF-Canon / Michële_DEPRAZ
35
Impacts of Land Clearing
WWF-Australia
...the long-term impacts of clearing native
vegetation are disastrous for wildlife in NSW.
36 Impacts of Land Clearing
WWF-Australia
1 2006 Australian State of the Environment Committee. 2006. Australia State of the Environment 2006.
Independent Report to the Australian Government Minister for the Environment and Heritage. Australian
Department of the Environment and Heritage: Canberra. [URL: http://www.deh.gov.au/soe/2006/
publications/drs/indicator/13/index.html] last viewed 16 January 2007.
2 2006 Australian State of the Environment Committee. 2006. Australia State of the Environment 2006.
Independent Report to the Australian Government Minister for the Environment and Heritage. Australian
Department of the Environment and Heritage: Canberra. [URL: http://www.deh.gov.au/soe/2006/
publications/report/land-1.html] last viewed 16 January 2007.
3 NSW Department of Environment and Conservation. 2006. NSW State of the Environment 2006. NSW
Dept of Environment and Conservation: Sydney. Section 6.1. [URL:http://www.environment.nsw.gov.
au/soe/soe2006/chapter6/chp_6.1.htm#6.1.11] last viewed 10 January 2007. Citing Coutts-Smith, A.J. and
Downey, P.O. 2006. The Impact of Weeds on Threatened Biodiversity in NSW, Technical Series no. 11, CRC
for Australian Weed Management Systems: Adelaide.
4 Cogger, H.G., Ford, H.A., Johnson, C.N., Holman, J. and Butler, D. 2003. Impacts of Land Clearing on
Australian Wildlife in Queensland. WWF Australia: Brisbane.
5 Cogger, H.G., Ford, H.A., Johnson, C.N., Holman, J. and Butler, D. 2003. Impacts of Land Clearing on
Australian Wildlife in Queensland. WWF Australia: Brisbane. Pg. 6.
6 For more detailed discuss of the extinction debt concept, refer to Cogger, H.G., Ford, H.A., Johnson, C.N.,
Holman, J. and Butler, D. 2003. Impacts of Land Clearing on Australian Wildlife in Queensland. WWF
Australia: Brisbane. Pp. 6-7, 9.
7 2006 Australian State of the Environment Committee. 2006. Australia State of the Environment 2006.
Independent Report to the Australian Government Minister for the Environment and Heritage. Australian
Department of the Environment and Heritage: Canberra. [URL: http://www.deh.gov.au/soe/2006/
publications/report/land-1.html] last viewed 16 January 2007.
8 Native Vegetation Conservation Bill, Second Reading at NSW Legislative Assembly Hansard web site.
[URL: http://www.parliament.nsw.gov.au/prod/parlment/hansart.nsf/8bd91bc90780f150ca256e630010302c/
ca256d11000bd3aa4a25656e000f218e!OpenDocument] last viewed 17 November 2006.
9 Native Vegetation Conservation Act 1997 (repealed). Section 3.
10 NSW Auditor-General. 2006. Regulating the Clearing of Native Vegetation: Follow-up of 2002 Performance
Audit. The Audit Office of NSW: Sydney. Pp. 2-3, 11.
11 NSW Scientific Committee, Clearing of native vegetation – key threatening process declaration.
[URL: http://www.nationalparks.nsw.gov.au/npws.nsf/Content/Clearing+of+native+vegetation+key+threatenin
g+process+declaration] last viewed 7 August 2006.
12 NSW Legislative Council Hansard, Second Reading at NSW Legislative Council Hansard website [URL:
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46dbb882a914442dca256dfd001a0ce9!OpenDocument] last viewed 17 November 2006.
13 Native Vegetation Act 2003. Sections 3, 8 and 9.
14 For example, Scully, L. 2003. Notes and Abstracts. Relationships between vegetation clearance and the
introduction of legislation in the Nyngan Region, Central Western NSW. Ecological Management &
Restoration 4(2): 150-153; Bedward, M., Sivertsen, D.P., Metcalfe, L.M., Cox, S J. and Simpson, C.S. 2001.
Monitoring the Rate of Native Woody Vegetation Change in the New South Wales Wheatbelt. Final Project
Report to the Natural Heritage Trust/ Environment Australia. NSW National Parks and Wildlife Service:
Hurstville, NSW; Keith, D. 2004. Ocean Shores to Desert Dunes: The Native Vegetation of NSW and the ACT.
NSW Department of Environment and Conservation: Sydney.
15 NSW National Parks and Wildlife Service web site. [URL: http://www.nationalparks.nsw.gov.au/npws.
nsf/Content/Clearing+of+native+vegetation] last viewed 7 February 2007.
16 NSW Depar tment of Environment and Conservation. 2006. NSW State of the Environment 2006. NSW
Dept of Environment and Conservation: Sydney. Section 6.1 (modified from Keith, D. 2004. Ocean Shores
to Desert Dunes: The Native Vegetation of NSW and the ACT. NSW Department of Environment and
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17 NSW Auditor-General. 2006. Regulating the Clearing of Native Vegetation: Follow-up of 2002 Performance
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18 Exact figures advised by Lucian McElwain,NSW Department of Natural Resources by email dated
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Vegetation. Follow-up of 2002 Performance Audit.
19 NSW Depar tment of Environment and Conservation. 2006. NSW State of the Environment 2006. NSW
Department of Environment and Conservation: Sydney. Section 6.1. [ URL: http://www.environment.nsw.
gov.au/soe/soe2006/chapter6/chp_6.1.htm#6.1.11] last viewed 10 January 2007. NSW Auditor-General. 2006.
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21 See NSW Depar tment of Natural Resources. 2007. NSW Native Vegetation Report Card. 1 January 2006 to
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22 This is distinct from extinction on a national basis.
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24 NSW Depar tment of Environment and Conservation threatened species web site. [URL: http://www.
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25 Some figures were published in the NSW State of the Environment Report 2006 for the period commencing
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26 The Auditor-General’s figures also include an estimate of illegal clearing for 2005.
27 Menkhorst, P. and Knight, F. 2001. A Field Guide to the Mammals of Australia. Oxford University Press:
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Forty-eight species are listed as vulnerable, 31 as endangered, 3 as critically endangered and 1 as conservation
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41
Dickman, C.R. 1994. Mammals of New South Wales: past, present and future. Australian Zoologist 29: 158-165.
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Audit. The Audit Office of NSW: Sydney.
... The most pervasive threat affecting almost all threatened species in NSW identified in this review was habitat loss through land clearing and degradation. Habitat loss through land clearing has been identified as the single greatest threat to biodiversity in NSW (DEC 2006, Johnson et al. 2007). Since 1788, at least 61% of the native vegetation of NSW has been cleared or substantially modified, as outlined in a report commissioned by WWF Australia (Johnson et al. 2007). ...
... Habitat loss through land clearing has been identified as the single greatest threat to biodiversity in NSW (DEC 2006, Johnson et al. 2007). Since 1788, at least 61% of the native vegetation of NSW has been cleared or substantially modified, as outlined in a report commissioned by WWF Australia (Johnson et al. 2007). At least 35.5 million hectares (44% of the State) was ringbarked between 1788 and 1921, mostly in the period 1893 to 1921 (Glanznig 1995). ...
... During this period, all major coastal river valleys in NSW were extensively cleared including the Bega, lower Shoalhaven, Hunter, Clarence, Richmond, Tweed and the Cumberland Plains. Also heavily cleared were agricultural areas of the sheep– wheat belt running along the western slopes and tablelands of NSW including what is now the ACT (Glanznig 1995)Johnson et al. 2007). The amount of illegal clearing is unknown.Johnson et al. (2007)also estimated that at least 11 million animals died or will die as a result of the land clearing in NSW between 1998 and 2005. ...
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... Factors that have influenced that shift in Australia include the evolution of animal welfare statutes in the Australian states and territories, government and non-government initiatives to communicate welfare issues (e.g. RSPCA Australia 2002; Cogger et al. 2003;Johnson et al. 2007;Commonwealth of Australia 2011;McLeod and Sharp 2014) and improvements in our understanding of how wild animals respond to non-lethal interactions with anthropogenic stressors (e.g. Bejder et al. 2009;Johnstone et al. 2012a;Brearley et al. 2013;van der Hoop et al. 2017;Tablado and Jenni 2017). ...
... An evaluation of the harm that land clearing causes to wildlife may seem unnecessary because there would appear to be little scientific controversy as to the basic proposition that clearing native vegetation kills animals living at that site (Ehmann and Cogger 1985;Glanznig 1995;Williams et al. 2001;Cogger et al. 2003;McDonald et al. 2003; Department of the Environment 2006; Johnson et al. 2007). Nonetheless, there are several reasons why it is timely to review the harm that land clearing causes in a journal read by wildlife researchers and managers and environmental consultants, as well as by other environmental administrators and professionals. ...
... Saunders et al. 1991;Ford et al. 2001;Lindenmayer and Fischer 2006;Ford 2011). There is, therefore, a basic commonality of interest between concerns about harm to individual animals and efforts focussed on conserving populations and species (Cogger et al. 2003;Johnson et al. 2007). On that basis, efforts to integrate consideration of the death, physical injury and other pathological conditions caused by land clearing into environmental decisionmaking should also support better conservation outcomes. ...
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Land clearing is a significant environmental issue in Australia and an area of active legislative reform. Despite evidence of the harm that land clearing causes to individual animals, such harm is either ignored or considered only indirectly in environmental decision-making. We argue that the harm that land clearing causes to animals ought to be identified and evaluated in decision-making relating to land clearing and consider the following three propositions in support: (1) land clearing causes deaths that are physically painful and psychologically distressing because of their traumatic and debilitating nature; (2) land clearing causes physical injuries, other pathological conditions, pain and psychological distress over a prolonged period as animals attempt to survive in the cleared environment or in the environments they are displaced to; and (3) on the basis of current clearing rates, more than 50million mammals, birds and reptiles are likely to be killed annually because of land clearing in Queensland and New South Wales. The scientific consensus about the harm caused by land clearing means that decisions to allow land clearing are decisions to allow most of the animals present to be killed and, as such, frameworks for decision-making ought to include proper evaluation of the harm to be imposed.
... Dickman's estimate was based on the method of Johnson et al. (2007), which entailed multiplying areas of habitat destroyed by vertebrate animal density estimates that were available at the time. ...
... Some species may be able to flee fire, seeking shelter and migrating to new habitat. However, landclearing decreases habitat availability and connectivity, thus reducing availability of refuges, and has altered fire regimes in Australia (Johnson et al. 2007). ...
... Estimates of the numbers of animals impacted by the fires were obtained using estimates of fauna densities in NSW by Johnson et al. (2007). The majority of animals impacted are likely to have died as a result of the drought, the fires and the shortage of food, water and shelter after the fires. ...
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The year 2019 was Australia’s hottest and driest on record (Abram et al. 2021) and culminated in the catastrophic ‘Black Summer’ bushfires of spring and summer 2019-20. More than 23% of the temperate forests of south-eastern Australia were burnt in this one fire season, making the scale of the fires unprecedented both for Australia and globally (Boer et al. 2020). One of the worst affected areas was the Greater Blue Mountains World Heritage Area and surrounds, including the proposed Gardens of Stone State Conservation Area (SCA), which encompasses Newnes, Wolgan and Ben Bullen State Forests. The proposed SCA has a total area of 34,330 ha. This report documents the extent and severity of the 2019-20 fires in the proposed SCA based on a QGIS analysis of spatial data from the NSW Government’s Fire Extent and Severity Mapping (FESM) project (https://datasets.seed.nsw.gov.au/dataset/fire-extent-and-severity-mapping-fesm). FESM is a collaborative project between NSW Department of Planning, Industry and Environment and NSW Rural Fire Service. It is a semi-automated approach to mapping fire extent and severity through a machine learning framework based on Sentinel 2 satellite imagery (Department of Planning, Industry and Environment 2020). An earlier version of the report (Smith 2020) was based on FESM Version 2 (19-3-2020) mapping. However, the FESM mapping has since been updated and the current FESM Version 3 (18-12-2020) is substantially different. For example, the estimated proportion of the proposed Gardens of Stone SCA burnt at extreme severity has increased from 6% (Version 2) to 34% (Version 3). It has thus been necessary to update the earlier report.
... Estimates of the numbers of native animals impacted by the fires were obtained using estimates of fauna densities in NSW by Johnson et al. (2007). The majority of the animals impacted are likely to have died as a result of the drought, the fires and the shortage of food, water and shelter after the fires. ...
Technical Report
Full-text available
The year 2019 was Australia’s hottest and driest on record (Abram et al. 2021) and culminated in the catastrophic ‘Black Summer’ bushfires of spring and summer 2019-20. More than 23% of the temperate forests of south-eastern Australia were burnt in this one fire season, making the scale of the fires unprecedented both for Australia and globally (Boer et al. 2020). One of the worst affected areas was the Greater Blue Mountains World Heritage Area, which encompasses over one million hectares of native bushland in the ranges west of Sydney. It is an area of international significance because of its exceptional floral and faunal biodiversity. This report documents the extent and severity of the 2019-20 fires in the World Heritage Area based on a QGIS analysis of spatial data from the NSW Government’s Fire Extent and Severity Mapping (FESM) project (https://datasets.seed.nsw.gov.au/dataset/fire-extent-and-severity-mapping-fesm). FESM is a collaborative project between NSW Department of Planning, Industry and Environment and NSW Rural Fire Service. It is a semi-automated approach to mapping fire extent and severity through a machine learning framework based on Sentinel 2 satellite imagery (Department of Planning, Industry and Environment 2020). An earlier version of the report (Smith 2020) was based on FESM Version 2 (19-3-2020) mapping. However, the FESM mapping has since been updated and the current FESM Version 3 (18-12-2020) is substantially different. The estimated proportion of the World Heritage Area burnt in the fires has increased from 65% (Version 2) to 79% (Version 3). It has thus been necessary to update the earlier report.
... In particular, over 780,000 individual native mammals were estimated to have been condemned, on average, due to approved and illegal clearing each year, albeit with wide error margins above and below this average. 3 In 2005, the new Native Vegetation Act 2003 came into force. Broad-scale clearing of remnant bushland was prohibited unless it could be demonstrated that the clearing would "improve or maintain environmental outcomes", primarily by protecting areas of recovering bushland to offset the areas being cleared. ...
Technical Report
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In 2005, the Native Vegetation Act 2003 came into force. The Act was the result of an agreement between farmers, government, scientists and environmentalists. Under the Act, the broad-scale clearing of forests and woodlands (“bushland”) was prohibited unless it could be demonstrated that the clearing would “improve or maintain environmental outcomes”, primarily by protecting areas of recovering bushland to offset the areas being cleared. The Native Vegetation Act dramatically reduced the extent of landclearing approved in NSW and, in doing so, has saved the lives of hundreds of thousands of native mammals, as well as protecting forests and woodlands that provide an abundance of other benefits of economic value, including shelter for stock and crops from wind and weather; pest control and pollination; health, recreation and amenity benefits; climate moderation; and protection from erosion, waterlogging and salinity. Following the commencement of the legislation, approved clearing fell precipitously from about 80,000 hectares to only 911 hectares a year, on average, which represents an 88-fold reduction. Additionally, clearing approved after 2005 has been offset by protection and recovery of 7,852 hectares annually, on average. The Native Vegetation Act, along with other initiatives to expand protected areas, puts NSW in the forefront of protection of natural landscapes and the unique plant and animal species they support. Despite the dramatic reduction in clearing approvals, however, the area of remnant bushland actually cleared for agriculture or development has fallen by a lesser amount. About 15,730 hectares were still cleared for these purposes annually in the period 2006-2010 (exclusive of the area cleared under approvals over the same period), compared to 19,681 hectares cleared annually from 1998-2005, on average. This 20 per cent fall in actual remnant bushland clearing has meant that some 53,000 fewer native mammals have been killed each year since the law changed – a reduction of 14 per cent. However, about 320,000 mammals continue to be killed each year as a result of the ongoing clearing of remnant bushland other than clearing under approvals. We were not able to determine how much of this ongoing remnant clearing is legal by virtue of exemptions under the present legislation or approvals under other legislation, or is illegal. The NSW Government does not publicly report these data. The authors recommend that such data should be made publicly available. We only had access to data up to 2010, and more recent clearing data are likely to show more substantial declines in clearing rates than those reported here. WWF recommends the NSW Government: 1. Maintain the Native Vegetation Act 2003 in its existing form; 2. Quantify and report on the scale of ongoing illegal clearing; 3. Boost compliance capacity to reduce illegal clearing; 4. Continue the strategic growth of national parks and other protected areas; and 5. Ensure that voluntary private land conservation targets under NSW 2021 are met.
... In this case, reintroduction may be a tool for returning reptiles to restored forest following significant disturbance. Many reptile species have complex micro-habitat requirements, very small home ranges (often less than a few hundred square metres; Johnson et al. 2007) and low mobility. Some rely heavily on specific microhabitat features such as fallen logs, branches and other coarse woody debris for shelter, foraging and refuge from avian and terrestrial predators (Richardson 2006). ...
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Context The value of animal reintroduction as a conservation tool is debated. This is largely because the limited quantity of research that has been conducted on animal reintroductions has shown varying degrees of success in establishing new populations. The reasons why some reintroductions are successful, whereas others are not, are often not clear. Aims The present research aims to determine whether reptile reintroduction into restored mine pits is a potential management technique for managing and conserving reptile populations within a mined landscape. Methods Twelve Napoleon's skinks were trapped then fitted with 0.9-g transmitters. Half were reintroduced into 5-year-old restored mine pits and the other half into unmined forest. Bodyweights, movement patterns and macro-habitat selection were recorded weekly during November and then monthly until March. Key results Skinks reintroduced into restored sites quickly moved into unmined forest. Both groups of skinks moved large distances, but those reintroduced into restored sites travelled further than did control skinks and took longer to reduce their distances travelled, showing possible stress as a result of release into unsuitable habitat. Eventually, almost all skinks found suitable habitat in unmined forest and settled into these areas while continuing to gain weight. Conclusions Reintroduction was an ineffective technique for facilitating colonisation of restored minesites by Napoleon's skink. Lack of suitable micro-habitats within restoration areas, such as ground logs and coarse, woody debris piles, is likely limiting the use of these areas by Napoleon's skinks and is likely to be the cause of their failure to remain or settle in restored sites after reintroduction. Implications Determining the habitat requirements of skinks and replicating this in restoration sites would seem the more appropriate management option than is reintroduction, and this may be the case for other reptiles and habitat specialists.
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Bushfires in Australia in the “Black Summer” of 2019–2020 shocked the world. Research is allowing us to begin to appreciate the scale of the catastrophe for humans, other animals, and the environment. If we are to anticipate, mitigate, and prevent further catastrophes and to protect biodiversity as best we can, we must develop a comprehensive picture of the impacts of these recent bushfires, understand their causes, and trace where responsibility for their catastrophic impact on biodiversity falls. This opinion piece argues that doing so requires an analysis that combines legal, philosophical, and scientific lenses. Correlatively, a comprehensive response demands the rapid introduction of a range of scientific, legal, political, economic, and cultural changes, not simply to reduce fossil fuel emissions and better protect biodiversity, but to disable the ideological conditions that enable the existing policy framework. This article is categorized under: • Climate, Ecology, and Conservation > Conservation Strategies Abstract An ecological approach to understanding the causes and effects of the Black Summer fires
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Until recently, animal and plant extinctions were limited to ocean islands. Sadly, extinctions now have arrived on continents, as human populations have rapidly grown, enormous areas of natural habitat converted to agricultural land, hunting for food and poaching for “fake” medicines and jewelry increased, introduction of alien species expanded, and resource consumption and pollution have increased since WWII and exploded since the 1990s acceleration in globalization and global income disparity. Today 83% of all animals are domestic, while the loss and fragmentation of natural habitat and space is critically endangering much of the wildlife that is left. Poaching for elephant ivory, rhino horn, pangolin scales, and helmeted hornbill’s casque is at all-time high. Additionally, bush-meat consumption is contributing to the emergence of new pathogens.
Technical Report
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Executive summary • Internationally and nationally, habitat loss is the greatest threat to threatened species. • More than 400 ecologists, including leading conservation scientists from Australia and around the world, have issued a declaration in 2016 warning of the devastating impacts of land clearing on Australia’s biodiversity. • Numerous scientific, peer reviewed studies have been published warning of the impacts of land clearing on biodiversity and threatened species. • The woody vegetation clearing rate in Queensland increased in the period 2013-2015 to 296,000 hectares per year, and was 3.8 times the rate of woody vegetation clearing in 2009-10. • The Brigalow Belt, Central Queensland Coast, New England Tableland, Southeast Queensland and Wet Tropics bioregions are fragmented landscapes resulting from historical and recent land clearing. The Mulga Lands and Desert Uplands bioregions have been increasingly fragmented in recent years. • Land clearing causes species death and habitat loss, but also exacerbates other threatening processes, particularly in fragmented landscapes. • Land clearing reduces the resilience of threatened species populations to survive future perturbations such as climate change. • Apart from the immediate impacts of clearing, significant time lags occur before the full cumulative impact on biodiversity is realised. • The impact of the previous century of land clearing has resulted in small, fragmented relictual populations of many native species. Any further land clearing will further elevate the extinction pressure arising from loss of habitat and a range of other threatening processes which are exacerbated by fragmentation. • Land clearing has significant negative impacts offsite e.g. (sediment runoff into streams, rivers, wetlands and the Great Barrier Reef marine lagoon), and is a major contributor to climate change through greenhouse gas outputs, and rainfall and temperature dynamics. • Land clearing has been directly responsible for two plant species becoming extinct in the wild, and has been identified as a threatening process for many of the 739 threatened flora species and 210 threatened fauna species in Queensland. • Eight species are discussed in a series of case studies indicating the major reduction in the area and quality of habitat that historic and recent land clearing has caused. • The current State protected area estate and voluntary nature refuge estate combined only retain 11.4% of the pre-clearing potential habitat for terrestrial threatened species, and hence are unlikely to prevent further species from becoming extinct.
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This paper reviews the impacts of three species of introduced mammalian predators on native fauna in Australia. The feral cat Felis catus, introduced over 200 years ago, is linked with early continental extinctions of up to seven species of mammals, regional and insular extinctions of many more species of mammals and birds, and the failure of management programs attempting to reintroduce threatened native species to parts of their former ranges. Evidence for cat-impact is largely historical and circumstantial, but supported by observations that afflicted native species are, or were, small (<200 g) occupants of open habitat and hence likely to be especially vulnerable to cat predation. The red fox Vulpes vulpes was released successfully in 1871. Its subsequent spread into all except parts of arid and tropical Australia coincided with local and regional declines of medium-sized (450 - 5,000 g) mammals, birds and chelid tortoises. The fox has also created recent failures of many management attempts to recover threatened native species. Unequivocal demonstration of fox-impact has been obtained in removal experiments, especially on rock-wallables Petrogale lateralis. The dingo Canis lupus dingo, introduced 3,500-4,000 years ago, probably caused the extinction of the thylacine Thylacinus cynocephalus and Tasmanian devil Sarcophilus harrisii on mainland Australia. In effectively suppresses extant populations of large mammals, such as kangaroos, and emus, over large areas. Impacts of all three predators are wrought primarily by direct predation. Negative impacts appear to be increased in spatially fragmented forests where native species are restricted to remnant vegetation, and in arid landscapes when native species become restricted temporarily to scattered oases during drought. Alternative prey especially rabbits Oryctolagus cuniculus, enhance negative impacts on native species by supporting large populations of the predators. It is concluded that feral cats, and especially foxes have major negative impacts on certain small and medium-sized native vertebrates in Australia, whereas dingoes have major negative impacts on large species. Dingoes could have positive effects on smaller native species if they significantly suppress populations of foxes and cats. Further quantification of both the direct and indirect in pacts of the three predators on native fauna is needed and should be obtained from experimental field studies.
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A total of 131 non-marine species of native mammals, including the Dingo, Canis familiaris dingo, has been recorded in New South Wales since the early days of European settlement in 1788. Twenty-nine of these species are now extinct in the State; 21 species remain extant beyond the borders of New South Wales while eight species are entirely extinct. Most losses (21 species) occurred before 1900, particularly in the arid western region of the State. Overall, state-level extinctions represent 39.3% of native rodents (11 of 28 species), 27.0% of marsupials (17 of 63 species) and 2.7% of bats (one of 37 species). Forty-eight extant species of native mammals are considered to be presently endangered, including 20 species of marsupials, nine rodents and 19 bats. -from Author
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More than 300 species of Australian native animals — mammals, birds, reptiles and amphibians — use tree hollows, but there has never been a complete inventory of them. Many of these species are threatened, or are in decline, because of land-use practices such as grazing, timber production and firewood collection. All forest management agencies in Australia attempt to reduce the impact of logging on hollow-dependent fauna, but the nature of our eucalypt forests presents a considerable challenge. In some cases, tree hollows suitable for vertebrate fauna may take up to 250 years to develop, which makes recruiting and perpetuating this resource very difficult within the typical cycle of human-induced disturbance regimes. Tree Hollows and Wildlife Conservation in Australia is the first comprehensive account of the hollow-dependent fauna of Australia and introduces a considerable amount of new data on this subject. It not only presents a review and analysis of the literature, but also provides practical approaches for land management.
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Apart from the small though vital contribution of nature conservation reserves (which account for 4% of Australia's surface area), the conservation of Australia's herpetofauna is currently legislatively-based on either the protection of species-as-individuals at a regional or national level, or, at an international level, on preoccupation with rarely-found forms. The criteria used by both government and non-government conservation agencies in establishing legislation and policies are argued to be deficient. Frequent preoccupation with individual organisms or assumed rarity results in serious inconsistencies, and has distracted legislators from the more pressing need to conserve populations and habitats. -from Authors
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Following 2 introductory chapters, contributions are arranged in 3 sections: bird communities in forests and woodlands (9 papers); ecology and adaptations of forest and woodland birds (10 papers); and human impact-the response of forest and woodland bird communities (10 papers). Each section has its own introduction, and the final paper in each section provides a synthesis. All 31 contributions are abstracted separately. -P.J.Jarvis
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The Tall Open and Open Eucalyptus forests of southeastern and southwestern Australia and of Tasmania sustain 57 species of indigenous mammals. Between 10 and 20 of the species are wholly dependent on these forests for their survival and have evolved adaptations to suit a stable environment. The rest are less dependent and use the forests mainly as shelter. Compared to southeastern Australia the mammal faunas of the other two regions are depauperate, and the missing species are generally those considered to be wholly dependent. It is suggested that their dependence on the forests prevented them crossing non-forested barriers during the Pleistocene.
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(1) Wet sclerophyll forest being clear-felled for pine plantations in New South Wales, contains several species of arboreal marsupial. The fate of one of these species, Schoinobates volans, has been followed by marking and recapture of the entire population in an area of 4300 ac during 6 years. (2) A total of 1038 adult and immature gliders and 319 pouch young were marked and released at the point of capture during clear felling. One-quarter of these were recaptured in the same season, over 70% within the first week after initial capture; very few were recaptured more than once. These short term recaptures had lost up to 25% of their body weight and many breeding females had lost pouch young. (3) Less than 7% of the animals marked were recaptured 1 year after marking, but unlike the short term recaptures these animals had gained weight and had advanced their reproductive status. In half the cases these animals had moved only short distances in the intervening year and just across the boundary between the felled and standing forest and it was concluded that those animals are most likely to survive felling whose immediate environment is only partially destroyed by felling. (4) Prior depletion of the glider population in a block of forest in the last year of the study did not increase the survival of marked animals or their movement into the depleted forest. It was concluded from this that the displaced gliders die in situ rather than emigrate to occupied forest and die there through failure to become established.