LANDCLEARING IMPACTS OF - The Impacts of the Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales - WWF-Australia

LANDCLEARING IMPACTS OF - The Impacts of the Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales - WWF-Australia
The Impacts of the Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales
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 © WWF-Australia. All Rights Reserved.
 WWF-Australia Head Office
 GPO Box 528, Sydney, NSW, Australia 2001
 Tel: +612 9281 5515 Fax: +612 9281 1060
 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.
                  Impacts of Land Clearing
 ISBN: 1 921031 17 4
 World Wide Fund forWWF-Australia
                    Nature ABN: 57 001 594 074
ABOUT THE AUTHORS                   2
EXECUTIVE SUMMARY                   4
1. BACKGROUND                       6
2. MAMMALS                      12
3. BIRDS                        20
4. REPTILES                     28
5. CONCLUSION                   34
REFERENCES                      36

                Impacts of Land Clearing
DR HAL COGGER                                                               PROFESSOR CHRIS DICKMAN
REPTILES                                                                    MAMMALS
Dr Hal Cogger is a leading Australian herpetologist and author of the       Professor Chris Dickman is a highly respected scientist with nearly
definitive Reptiles and Amphibians of Australia. He is a former Deputy       30 years’ experience of working on the ecology, conservation and
Director of the Australian Museum.                                          management of Australian mammals. Since 1990, he has been Director of
                                                                            the Institute of Wildlife Research at the University of Sydney. In 2004, he
Dr Cogger has participated on a range of policy and scientific committees,   was awarded a personal chair in ecology at the university.
including the Commonwealth Biological Diversity Advisory Committee,
Chair of the Australian Biological Resources Study Advisory Committee       For much of the last 20 years, Professor Dickman has studied the factors
and Chair of the Australasian Reptile & Amphibian Specialist Group          that influence vertebrate diversity in arid Australia. In this work, he has
(IUCN’s Species Survival Commission). He also held a Conjoint               identified habitat loss, feral cats and foxes as being particularly detrimental
Professorship in the Faculty of Science & Mathematics at the University     to the survival of native fauna.
of Newcastle (1997-2001).
                                                                            Professor Dickman is a past President of the Australian Mammal Society and
He is currently the John Evans Memorial Fellow at the Australian Museum.    of the Royal Zoological Society of New South Wales, past Chair of the NSW
                                                                            Scientific Committee, and Chair of the Australian Marsupial and Monotreme
Hal Cogger’s research interests include the systematics and ecology         Specialist Group for the Species Survival Commission of the IUCN.
of Australian reptiles and frogs and the role of threatened species in
conservation biology and policy development. He is senior author of the     Professor Dickman currently serves on the national assessment panel for
Action Plan for Australian Reptiles.                                        the Threatened Species Network Community Grants Program, the NSW
                                                                            Biodiversity Research Network, and the Scientific Advisory Committee for
For his contribution to Australian herpetology, Dr Cogger has been          Earthwatch.
awarded an AM, an honorary Doctor of Science from the University
of Sydney, and honorary life memberships of the Australian Society of       Professor Dickman has written or edited 16 books and monographs and
Herpetologists, the American Society of Ichthyologists and Herpetologists   authored a further 220 journal articles and book chapters. He is a recipient of
and The Herpetologists’ League, Inc. He is a recipient of the Whitley       a Bolliger Award and Troughton Medal from the Australian Mammal Society.
Medal of the Royal Zoological Society of NSW.
                                                                            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.

         Impacts of Land Clearing
  2           WWF-Australia
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.

                                                                               Impacts of Land Clearing

This report uses the amount of land    Due to inadequate or uncertain          NSW Government approved
in New South Wales approved by         public data, the figures in this         639,930 hectares for clearing under
the State Government for clearing      study do not include the numbers        its native vegetation legislation.
between 1998 and 2005 inclusively      of animals killed as a result of
to calculate the impacts of land       illegal clearing that occurred in       NSW’s wildlife is seriously
clearing on the State’s wildlife.      NSW from 1998 to 2005, or as            threatened and under increasing
                                       a result of exempt clearing (ie         pressure from a range of traditional
According to these calculations        legally permitted clearing that         threats, such as the clearing of
more than 104 million native           does not require approval) that         native vegetation and the impacts
mammals, birds and reptiles have       occurred during this time. These        of exotic pests, as well as more
died or will die as a result of the    other clearing activities also result   recent factors, such as climate
clearing of native vegetation          in the deaths of many millions          change. NSW can stop the loss and
in NSW approved between 1998           of native animals. For example,         degradation of valuable habitats
and 2005.                              around 5 million mammals, birds         immediately by arresting the extent
                                       and reptiles would have been killed     of clearing and fragmentation of
These include:                                                                 native vegetation, particularly west
                                       by the amount of illegal clearing
• over 11 million mammals with         estimated by the Auditor-General        of the Great Dividing Range, and
  possums and gliders most             to have occurred in 2005.               by undertaking the level of research
  severely affected as well as                                                 and monitoring that is essential
  many millions of kangaroos,          This study does not include any         to managing natural resources at
  wallabies, bandicoots, koalas        estimates of the amphibians, fish        sustainable levels. Alternatively,
  and wombats;                         and invertebrates that were also        NSW can continue to allow native
• around 13 million birds              killed as a direct or indirect          habitats to be lost or degraded
  comprising mostly woodland           result of the approved clearing         and experience irreversible regional
  and forest birds and including       of native vegetation.                   population declines
  species of honeyeaters and                                                   and extinctions.
                                       The study used the known record
  babblers that are under threat
                                       of approved clearing of native
  of extinction in NSW; and
                                       vegetation in NSW from 1998 to
• more than 80 million reptiles        2005 inclusively that was published
  such as skinks and geckos.           by the Auditor-General in his 2006
These estimates are highly             report, Regulating the Clearing of
conservative and the true mortality    Native Vegetation: Follow-up of
is likely to be substantially higher   2002 Performance Audit. Between
than those estimated in this report.   1998 and 2005 inclusively, the

          Impacts of Land Clearing
   4             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

                                                    Impacts of Land Clearing

1.1                                      In 2003, the WWF-Australia
                                         report, Impacts of Land Clearing
                                                                                 habitats for short-term gains and
                                                                                 reduced their diversity, adaptability
IMPACTS ON                               on Australian Wildlife in               and long-term productivity through      PROTECTION
WILDLIFE                                 Queensland, analysed the impacts
                                         of the loss of native vegetation
                                                                                 loss of species richness. The
                                                                                 resultant debt is likely to fall due    OF NATIVE
OF LOSS                                  on key elements of Queensland’s         in 20 to 50 or more years’ time and     VEGETATION
                                         wildlife.4 That report outlined the     will therefore be paid by future
OF NATIVE                                profound effects, both immediate        generations as local extinctions        IN NSW
VEGETATION                               and long-term, of the clearing of
                                         native vegetation on the survival of
                                                                                 gradually become regional until
                                                                                 entire species are made extinct.6
                                                                                                                         It is almost a decade since a NSW
                                                                                                                         Government recognised through
The Australia State of the               Australian wildlife, including the
                                                                                 As noted by the Australia State of      legislation that the loss or clearing
Environment 2006 report states that      deaths of many millions of native
                                                                                 the Environment 2006 report, the        of native vegetation causes serious
when land is cleared “everything         mammals, birds and reptiles.
                                                                                 detrimental effects of vegetation       loss of biodiversity.8
that lives in it is killed.” 1
                                         When an area of native bushland is      change extend “beyond the number
                                                                                                                         In 1997, NSW passed the Native
The impacts of the loss of native        lost, most of the resident wildlife     of hectares cleared or replanted
                                                                                                                         Vegetation Conservation Act 1997
vegetation on Australian wildlife        does not simply relocate. In reality,   each year”. Any vegetation
                                                                                                                         with the object of conserving and
are well recognised. For example,        the vast majority of animals will       that regrows or replaces cleared
                                                                                                                         managing native vegetation.9 In
the 2001 national report, Australia:     die. Most will die quickly but others   vegetation, whether natural
                                                                                                                         2002, the Auditor-General found
State of the Environment 2001,           survive for a time before succumbing    regeneration or planted trees,
                                                                                                                         that “the system for regulating the
identified the clearing of native         to starvation, predation or other       is rarely like the communities
                                                                                                                         clearing of native vegetation was
vegetation as the biggest threat to      fates. This can lead to the local and   that were previously cleared. For
                                                                                                                         ineffective” due to deficiencies
Australia’s wildlife. The Australia      regional extinction of populations      example, dense woody shrubs
                                                                                                                         in accountability, planning,
State of the Environment 2006            and, through successive cycles of       may form a monoculture in place
                                                                                                                         information, enforceability,
report identifies the clearing of         local impacts and fragmentation,        of a naturally occurring, complex
                                                                                                                         monitoring and reporting. As
native vegetation as “an ongoing         the decline and, in some cases,         ecosystem.7 It also takes a very
                                                                                                                         noted by the Auditor-General in
threat to Australia’s environment”.2     extinction of entire species.5          long time for some components of
                                                                                                                         2006, “this regulatory system
The 2006 NSW State of the                                                        the ecosystem critical to wildlife
                                         A further consequence of this                                                   continued until December 2005
Environment report also concluded                                                habitat to be replaced, such as tree
                                         extinction process is that it can                                               and continued to be ineffective”.10
that the clearing of native                                                      hollows, extensive areas of bark
                                         take decades or more for the full       and large trees.
vegetation, with the associated                                                                                          In 2001, NSW formally listed
                                         effects of land clearing to appear
destruction of habitat, is “the                                                                                          the clearing of native vegetation
                                         – a time lag that is referred to as
greatest single threat to biodiversity                                                                                   under its Threatened Species
                                         an extinction debt. The debt arises
in NSW”. 3                                                                                                               Conservation Act 1995 as a “key
                                         because we have “borrowed” rich
                                                                                                                         threatening process” that harms

          Impacts of Land Clearing
   6           WWF-Australia
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.

threatened species, populations or     in parts of the State over a long
ecological communities, or could       time.14 Similarly, NSW has not
cause other species to become          established a comprehensive
threatened. At the same time, the      system for adequately monitoring
Scientific Committee established        and reporting changes to the
by the Threatened Species              State’s vegetation cover. Proper
Conservation Act found that the        monitoring of all the State’s
clearing of any area of native         vegetation and a rigorous
vegetation in NSW, including areas     classification system is essential
less than two hectares in extent,      to enable future planning and
may have significant impacts on         management of the State’s
biological diversity.11                resources and to ensure that
                                       adequate and representative
In 2003, the NSW Government            protection of our biodiversity takes
stated its “commitment to end          place. This is crucial for a wide
broadscale clearing and maintain       variety of reasons, not the least to
productive landscapes” 12 and          ensure the continued functioning
passed the Native Vegetation Act       of our landscapes and ecosystems.
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
                                                                                                         © Richard McLellan

                                                                              Impacts of Land Clearing

                                                             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.

                                                             Figure 1. Map of existing native
                                                             vegetation in NSW, 200516
                               © WWF Canon / Michel DEPRAZ

                                                                Wet sclerophyll forests (shrubby subformation)
                                                                Wet sclerophyll forests (grassy subformation)
                                                                Grassy woodlands
                                                                Dry sclerophyll forests (shrub/grass subformation)
                                                                Dry sclerophyll forests (shrubby subformation)
                                                                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)
    Impacts of Land Clearing
                                                                Cleared land

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.

During the years 1998 to 2005            Approved clearing has been             In February 2007, the NSW
inclusively, 639,930 hectares of         greatest in areas to the west of the   Government reported that, on
native vegetation was approved           Central Division for agriculture,      average, around 16,000-18,000
for clearing in NSW. It is noted         and in coastal regions for urban       hectares of woody vegetation had
that these figures do not include         development. The greatest area of      actually been cleared in NSW
areas of native vegetation subject       new clearing of native vegetation      during a two year period between
to illegal clearing or exempt            in NSW since 1997 has taken place      2004 and 2006.20 This compares
clearing (i.e. clearing that may be      in the central west and north west     with the Auditor General’s estimate
legally carried out under the Native     of the State. Within these western     of around 75,000 hectares for
Vegetation Act without approval).17      areas, the most intensive clearing     2005 alone. The huge discrepancy
                                         has been in the hotspot area around    between the Auditor-General’s
The table below sets out the             Walgett, Nyngan and Tottenham.         figures and these latest findings
known record of clearing of native       New clearing in the State’s western    has not been comprehensively
vegetation approved by the NSW           areas has been attributed to the       explained. The NSW Government
Government in NSW from 1998              development of new strains of          also reported on new clearing
to 2005. The Auditor-General also        wheat suitable for arid climates       approvals for the first six months
estimated that 30,000 hectares of        which have provided a financial         of 2006.21
illegal clearing took place in 2005.     incentive for clearing native
                                         vegetation in areas previously
                                         considered too arid for crops.19

        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

                                                                                                                      Impacts of Land Clearing

1.4                                    Eighty-two per cent of the
                                       terrestrial or non-marine
                                                                              The following table sets out the
                                                                              numbers of terrestrial or non-
NSW WILDLIFE                           species had the clearing of            marine mammals, birds and reptiles

UNDER THREAT                           native vegetation listed as a key
                                       threatening process under the
                                                                              listed by NSW as threatened
                                                                              with Statewide extinction and the
FROM LOSS                              NSW Threatened Species                 number having land clearing as a
                                       Conservation Act.                      key threatening process.
VEGETATION                                                    No.          No. with land    Percentage of
                                                          threatened         clearing as    species having
Significant loss of native vegetation
                                                                           key threaten-   land clearing as
and the associated destruction of
                                                                            ing process    key threatening
habitat continues to occur in NSW
despite the fact that NSW wildlife
is already under siege.                  Mammals               57               49                86%
In NSW, 315 animal species or               Birds              88               72                82%
populations are listed as threatened    (non-marine,
with Statewide extinction.22 This       not offshore)
                                           Reptiles            36               28                78%
• amphibians – 27;                       (terrestrial)
• aquatic invertebrates – 3;
                                           TOTAL              181              149                82%
• bats – 21;
• birds – 115;                         Table 2: Terrestrial or non-marine mammals, birds and reptiles
                                       listed by NSW as threatened with Statewide extinction by the end
• endangered populations – 36;
                                       of 2006 and the number having land clearing as a key threatening
• fish – 12;                            process under the NSW Threatened Species Conservation Act 24
• invertebrates – 14;
• marine mammals – 7;
• marsupials – 24;
• reptiles – 44; and
• rodents – 12.23

          Impacts of Land Clearing
 10            WWF-Australia
• 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,

                                                                                                                   Impacts of Land Clearing

2.1                                    these being extinct Australia-wide.
                                       An additional 50 species were still
                                                                               is a lack of detailed information
                                                                               on the types of vegetation that
OVERVIEW                               present but were threatened with        are currently being cleared, the       NUMBERS OF
Australia supports a rich and
                                       extinction in the future. Several
                                       species have since been added
                                                                               available data indicate that large
                                                                               areas of the central west and          MAMMALS
impressive diversity of mammals,
with over 300 native species
                                       to the original stock-take due to       Barwon regions are being affected,     KILLED BY
                                       more survey work and taxonomic          as well as parts of the eastern
occupying the land.27 The              revisions but the perilous state of     catchment of the Darling River.        VEGETATION
continent is unique in being
dominated by marsupials, and in
                                       the majority of NSW mammals
                                       remains unchanged.
                                                                               Clearing in these areas removes
                                                                               diverse vegetation types that can
                                                                                                                      LOSS IN NSW
being the only great land mass to                                              be classified broadly as woodland       • More than 11 million
contain representatives of the three   In general, mammals are more            and parkland. Many mammals that
                                       diverse and abundant in the higher                                               native mammals died
major groups of living mammals:                                                already occur sparsely in these
the marsupials, monotremes (the        rainfall coastal regions of NSW                                                  or will die in NSW as
                                                                               vegetation types are being pushed
egg-laying platypus and echidna)       and on the slopes and tablelands                                                 a result of the clearing
                                                                               to the brink of regional extinction,
and placentals. About 244 species,     of the Great Dividing Range. These      and those with bigger populations        of native vegetation
or 81% of this distinctive fauna,      regions remain the strongholds          or broader geographical ranges           approved between
are found only in Australia, with      for many of the tree-dwelling           are being reduced, fragmented            1998 and 2005.
the others occurring also in the       marsupials, rodents and bats,           and placed at future risk as more
New Guinea region.28 Some 27           and provide the major refuges                                                  It is conservatively estimated that
                                                                               vegetation is destroyed. Clearing
species and subspecies of native       for specialist species such as the                                             over 11 million mammals will die
                                                                               of vegetation in coastal areas for
mammals have become extinct in         platypus and mountain pygmy-                                                   or have already died as a result of
                                                                               development can also be expected
Australia over the last 200 years,     possum. With declining rainfall                                                land clearing approved in NSW
                                                                               to have very negative consequences
the highest rate of loss for any       inland, tree cover becomes more                                                between 1998 and 2005 inclusively.
                                                                               for mammals, but there is no
region in the world. 29                sparse and gives way in parts of        reliable information on how much       As noted previously, this estimate
                                       the far west of the State to arid       vegetation is destroyed there.
A detailed stock-taking in 1992                                                                                       does not include the number of
                                       and semi-arid shrubland and
found records of 130 species of                                                                                       mammals killed by illegal or
                                       grassland. These drier habitats still
native mammals in NSW.30 Of                                                                                           exempt clearing. For example,
                                       provide homes for many species
these, 63 were marsupials, 28                                                                                         around half a million mammals
                                       of native mammals, but the low
were rodents and 37 were bats; the                                                                                    would have been killed by
                                       and uncertain productivity of the
two remaining species were the                                                                                        the amount of illegal clearing
                                       environment means that these
echidna and platypus. Disturbingly,                                                                                   estimated by the Auditor-General
                                       species typically survive ‘on the
the stock-take found that 27 of                                                                                       to have occurred in 2005.
                                       edge’ at lower and precariously
the original species no longer         variable densities. Although there
occurred in NSW, with eight of

          Impacts of Land Clearing
 12            WWF-Australia
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.

Possums and gliders are affected
                                       © Klein & Hubert

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.

                                                          Impacts of Land Clearing

                                             2.3                                    native mice and rats, etc. When
                                                                                    averaged across the broad habitat
                                             HOW HAVE                               types in which the studies had been

                                             THESE                                  conducted, mean densities for each
                                                                                    of the different mammal groups
                                             NUMBERS                                ranged from 0.01 – 15.5 animals
                                                                                    per hectare, with higher values
                                             BEEN                                   being obtained usually in studies
                                             ESTIMATED?                             carried out in coastal regions than
                                                                                    on the tablelands, western slopes
                                             The numbers of native mammals          of the Great Dividing Range,
                                             killed by approved vegetation          and plains. Because the most
                                             clearing were estimated by, firstly,    clearing occurred in the central and
                                             obtaining estimates of mammal          western regions of NSW, only the
                                             population density in NSW and,         lower density estimates were used
                                             secondly, multiplying these density    in analyses.
                                             estimates by the areas of vegetation
                                                                                    Estimates of population density
                                             approved to be cleared in order to
                                                                                    were based on species-specific
                                             obtain the numbers of mammals
                                                                                    estimates as well as broader survey
                                             impacted by the clearing process.
                                                                                    studies that survey a range of
                                             Estimates of density were obtained     species in an area and sample the
                                             from published studies of mammals      various habitats that are available.
                                             in NSW and from studies carried
                                                                                    The following table sets out the
                                             out in other parts of Australia in
                                                                                    estimates of density of native
                                             similar habitats to those present
                                                                                    mammals from different habitats
                                             in NSW (Table 3). Many of these
                                                                                    and regions in NSW and total
                                             studies targeted just one or a small
                                                                                    numbers that have died or will
                                             number of species of mammals,
                                                                                    die as a result of land clearing
                                             and these have been grouped
                                                                                    approved in 2005.
                                             for simplicity into the broader
                                             categories of possums and gliders,
© Chris Dickman

                  Impacts of Land Clearing
       14             WWF-Australia
Mammal species/             Densities (numbers of animals per hectare) in    Numbers killed by                      eucalypt forests of northern NSW.
      group                   forest, woodland and scrub: means are shown       approved clearing                      PhD thesis, University of Sydney:
                                in bold with range, if available, in brackets* per year (2005 data)**                  Sydney; and numerous chapters in
                                                                                                                       books edited by Goldingay, R.L.
                                Coast and eastern         Tablelands, western                                          and Jackson, S.M. (eds). 2004. The
                                     ranges                slopes and plains                                           Biology of Australian Possums and
          Echidna                        0.01                      0.02                        898                     Gliders. Surrey Beatty & Sons:
           Koala                 0.05 (

2.3                                    • The densities of several
                                         common species, such as the
                                                                                this category, the planigales,
                                                                                Planigale gilesi and
HOW HAVE                                 brown antechinus (Antechinus           P. tenuirostris, and Forrest’s      DO MAMMALS
THESE                                    stuartii), agile antechinus
                                         (A. agilis), yellow-footed
                                                                                mouse Leggadina forresti).
                                                                                Although these latter species       DIE WHEN
NUMBERS                                  antechinus (A. flavipes) and            sometimes occur in wooded           THEIR NATIVE
                                         brushtail possum (Trichosurus          habitats, most records in NSW
BEEN                                     vulpecula) have been measured          are from open habitats that are     HABITAT IS
ESTIMATED?                               in several studies, with most
                                         yielding low to moderate
                                                                                not likely to be cleared.33
                                                                             • As noted, the usually lower
Continued                                densities but small numbers           densities obtained from studies      Does vegetation clearing actually
                                         of studies yielding very high         carried out in the tablelands,       kill mammals, or simply displace
Several decisions were taken that        estimates. To reduce bias             western slopes and plains were       them? From an ecological
have led to very conservative            arising from these rare high          used in preference to the higher     perspective, clearing of vegetation
estimates of numbers being made.         values, means for each species        estimates obtained in surveys        has several immediate effects on
Specifically:                             were first calculated as log-          further east.                        the mammals that use it. Some
• Many species were excluded             transformed densities and then                                             individuals can be expected to die
                                                                             Despite the uncertainties inherent
  from estimates because there           back-transformed to produce                                                of injury or trauma sustained during
                                                                             in extrapolating numbers of
  is insufficient information on          normal values. This method was                                             the clearing process. For survivors,
                                                                             animal mortality over large
  their abundance. The largest           used also by Cogger et al.32                                               clearing removes shelter from the
                                                                             areas, the above points ensure
  omission is the entire NSW bat       • Several species were omitted                                               extremes of weather, cover from
                                                                             that the estimated numbers are
  fauna (37 species), for which          from consideration due                                                     predators, depletes or destroys food
                                                                             conservative. Omission of the
  no information on density could        to uncertainty about how                                                   resources, and disrupts the familiar
                                                                             bat fauna alone will lead to a
  be found.                              vegetation clearing would affect                                           home range and social environments
                                                                             substantial underestimation of
• Many small mammals in                  them. Exclusions included red       the true impact of vegetation          that individuals experienced pre-
  semi-arid and arid regions             kangaroos (Macropus rufus),         clearing, even though it is known      clearing. The cleared environment
  exhibit large fluctuations              eastern grey (M. giganteus)         to be a highly destructive process     is therefore inimical to the survival
  in density depending on                and western grey kangaroos          for many species34. In addition,       of mammals. Some species such
  the prevailing weather. For            (M. fuliginosus), which can         habitats near cleared areas are        as large kangaroos make use of
  example, historical accounts of        flee clearing operations that        usually reduced in quality due         open pastures, but still need some
  the long-haired or plague rat          are in progress; rock-wallabies     to the effects of fragmentation        remnants of scrubbier vegetation
  (Rattus villosissimus) suggest         (Petrogale species), platypus       and processes that occur along         for shelter.
  that densities well in excess of       (Ornithorhynchus anatinus),         the boundary of the cleared area,
  1000 animals per hectare can                                                                                      If mammals cannot survive in
                                         the water rat (Hydromys             including increased access by pests
  be attained after years of good                                                                                   a newly-cleared environment,
                                         chrysogaster) and the dusky         and feral predators such as foxes.35
  rain31, with the species virtually                                                                                can they survive if they move to
                                         hopping-mouse (Notomys              Although these indirect effects of
  disappearing again during                                                                                         uncleared areas of vegetation?
                                         fuscus), as these species occupy    vegetation clearing are less obvious
  drought. For such eruptive                                                                                        The answer is ‘no’, for several
                                         habitats not directly subject to    and longer-term, they highlight
  species, only the low-density                                                                                     reasons. Firstly, except for some
                                         clearing; and species that are      the conservative nature of the
  population estimates were used.                                                                                   desert-dwelling species most native
                                         largely restricted to arid desert   estimates that we provide here.
                                                                                                                    mammals are sedentary, and many
                                         country with few trees and
                                                                                                                    will even ‘home’ back to a familiar
                                         shrubs (three species were in
                                                                                                                    location if they are displaced.

          Impacts of Land Clearing
 16            WWF-Australia
Within Australia, NSW has a particularly poor
                                         conservation record for its mammals, with the
                                         worst-affected regions lying west of the Great
                                         Dividing Range

Secondly, uncleared areas of
vegetation will be occupied by
                                         2.5                                   regions lying west of the Great
                                                                               Dividing Range39. These regions
                                                                                                                      were seen as continuing without
                                                                                                                      check, and reducing the State’s
resident animals. In the                 FUTURE OF                             are where much vegetation clearing     mammal fauna from its original
short-term, residents will often
repel intruders and prevent them         MAMMALS IN                            now occurs. Clearing of vegetation
                                                                               and subsequent land uses such as
                                                                                                                      130 species to just 53 species by
                                                                                                                      2038. The destruction of some
from relocating. In the longer           NEW SOUTH                             grazing and cropping have been         60% of the State’s native mammals
term, if displaced individuals                                                 identified previously as major          would be unprecedented on a world
do settle, they will increase            WALES                                 threats for mammals in these           scale. Continued land clearing has
demands on scarce resources in                                                 regions.40 Looking to the year         the potential to push us closer to
                                         As well as Australia having the
the reduced areas of uncleared                                                 2038, Dickman constructed three        this apocalyptic scenario.
                                         world’s highest extinction rate
land, and population numbers                                                   scenarios for NSW mammals.41
                                         for native mammals in the last
in the fragments will decline.                                                 The first scenario predicted
                                         200 years, a further 83 terrestrial
Thirdly, even if unoccupied land                                               increased mammalian diversity due
                                         species and subspecies are
is available, there is no guarantee                                            to discoveries in fauna surveys and
                                         currently listed as being at risk
that it will be suitable for displaced                                         research, and the second foresaw
                                         of extinction.38 Within Australia,
individuals to use. For example,                                               no change. In both scenarios, no
                                         NSW has a particularly poor
Tyndale-Biscoe and Smith                                                       further extinctions were envisaged.
                                         conservation record for its
experimentally removed greater                                                 In the third scenario, land clearing
                                         mammals, with the worst-affected
gliders (Petauroides volans) from                                              and other threatening processes
a block of forest and then waited to
see if gliders from a logged block
next to it would use it.36 They
                                          © WWF / Frédy MERCAY

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

                                                                                                                        Impacts of Land Clearing

                                                            GREATER GLIDER               disappeared had simply moved
Surveys in recent years have shown that over                (PETAUROIDES                 somewhere else? In this particular
300 species of native vertebrates use tree                  VOLANS)                      study the cleared forest was mostly
                                                                                         surrounded by pine plantations
hollows for shelter, with 83 of these species                 Occurring broadly in       and open farm land where gliders
(31%) being mammals. Many more species
                                     42                       forest and woodland in     cannot live. Searches for marked
                                                 eastern Australia, this large gliding   animals failed to find any there.
use trees and shrubs as arenas for social        possum depends on hollows in old        Greater gliders are typically
interactions, to move about in the canopy,       trees for shelter and specialises in    sedentary and are reluctant to
                                                 eating the leaves of a small number     move even if unoccupied forest is
to escape predators and other enemies on         of Eucalyptus species. During           available.
the ground, to search for insects and other      clearing operations animals may
                                                 escape being crushed by gliding         The authors concluded that, while
foods, or to eat the leaves, buds and flowers     as trees fall. In a detailed study by   few greater gliders are killed during
on the plants directly. For slow-moving
                                43               Tyndale-Biscoe and Smith45, near        tree fall, over 90% remain in their
                                                 Canberra, the authors captured          destroyed home range and die
species, such as koalas and possums, we          and marked every glider that            soon after. The immediate causes
can expect many individuals to be killed         escaped tree fall. Although the         of death are not known, but most
                                                 study extended for five years, more      likely include starvation, exposure
by the trauma of tree fall or by associated      than three quarters of the marked       and predation. Some animals
injuries sustained in the clearing operation.
                                          44     gliders were never seen again after     can survive, but only if at least
                                                 being marked. Of the few survivors,     part of their home range remains
If animals do survive the process of clearing,   almost three quarters were              uncleared.
what prospects do they have afterwards?          recaptured within eight days of tree
                                                 clearing; these had lost weight and
Quantitative information from two case           the females had lost their pouch
studies of possums and gliders shows that        young. The very few animals that
                                                 survived to the following year
most will die.                                   typically had home ranges that
                                                 overlapped a block of forest that
                                                 had not been felled. Is
                                                 it possible that the animals that

     Impacts of Land Clearing
18       WWF-Australia
© Viewfinder
           EASTERN                     boxes again. There was no evidence
           PYGMY-POSSUM                that the missing possums had
           (CERCARTETUS                relocated elsewhere. Apart from
           NANUS)                      being surrounded by open pasture,
                                       no marked animals were found in
             This diminutive possum    other forest remnants around the
lives in forest and heath-dominated    disrupted one, despite intensive
habitats in south-eastern Australia,   searching.
and visits flowers to obtain nectar,
pollen and occasional insects. It      There were two other unexpected
is listed as a vulnerable species in   findings in this study. Firstly, the
NSW. In the Dorrigo region on the      effects of the clearing appeared
New England Tablelands, eastern        to be much greater on females
pygmy-possums can sometimes            than on males. Prior to clearing
be found in scattered remnants         females comprised about 60%
of forest that has otherwise been      of the adult animals in the
cleared for cattle grazing. Studies    population, but in the six months
of this species in a small             post-clearing the sex ratio fell so
(4 hectare) remnant by Bladon          dramatically that just one animal
et al46 found that possums took        out of every five captured was
readily to nest boxes that were        female. Secondly, females that had
placed in trees, and used them         been carrying young before the
to rear their young. Eighteen          clearing event were not seen again,
months after the studies began, a      and recruitment of young to the
substantial portion of the remnant     population over the breeding season
(1.4 hectares, 35%) was cleared        was zero. These results suggest that
without warning by the land’s new      even partial clearing can have large
owner. Although two-thirds of the      and disproportionately negative
original habitat remained, monthly     effects on pygmy-possums and
capture rates of pygmy-possums         (to quote the authors) “support
fell from 33.5% to just 7.8%, and      concerns that the long-term survival
the population from 15-20 animals      of the eastern pygmy-possum in
to only 5-8. In percentage terms,      New South Wales is threatened by
these population reductions were       continued land clearing throughout
much greater than might have           much of its present range.”
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

                                                                              Impacts of Land Clearing

3.1                                                                           3.2
OVERVIEW                                                                      NUMBER OF BIRDS KILLED BY
Some 450 species of birds regularly occur in NSW and about half of            NATIVE VEGETATION LOSS IN NSW
these may be found in the eucalypt forests and woodlands of the Great
Dividing Range, western slopes and plains. Some 115 species of birds          • Some 13 million native birds died or will die in
(i. e. about 25%) in NSW are considered to be threatened with extinction        NSW as a result of the clearing of native vegetation
in the State. Twenty seven of these threatened species may be found in the      approved between 1998 and 2005.
woodlands and open forests west of the Great Dividing Range, that is in
                                                                              It is conservatively estimated that around 13 million birds have died or will
the habitats that have been most extensively cleared in the last 10 years.
                                                                              die as a result of the clearing of native vegetation approved between 1998
Most significantly, the loss and fragmentation of habitat, due to clearing,
                                                                              and 2005.
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 noted previously, this estimate does not include the number of birds
as the endangered regent honeyeater (Xanthomyza phrygia), swift parrot        killed by illegal or exempt clearing. For example, over half a million birds
(Lathamus discolor) and black-throated finch (Peophila cincta). The box-       would have been killed by illegal clearing in 2005 as estimated by the
ironbark forests of the slopes are also the major habitats for vulnerable     Auditor-General.
species such as the grey-crowned babbler (Pomatostomus temporalis),
diamond firetail (Staganopleura guttata) and black-chinned honeyeater          Although the birds that have died or will die will of course include
(Melithreptus gularis).47                                                     numerous common species, such as noisy miners (Manorina
                                                                              melanocephala) and striated pardalotes (Pardalotus striatus), they
In addition to these threatened species there is accumulating evidence        will include a number of species that are threatened in NSW such as
that many other birds of the inland woodlands and forests are declining       regent honeyeaters (Xanthomyza phrygia) and grey-crowned babblers
and disappearing locally. A continuation of broad-scale clearing of native    (Pomatostomus temporalis). Furthermore, an increasing number of
vegetation will mean that they may soon join the list of threatened species   woodland birds in NSW are known to be declining, with a likelihood
in the State.                                                                 that they will become threatened in the near future, if current threatening
                                                                              processes, such as loss of their habitat, continues.

          Impacts of Land Clearing
 20            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

                                    Impacts of Land Clearing

3.3                                     studies have been sought that
                                        estimate the densities of birds in
                                                                             birds in these sites range from
                                                                             under 10/ha in degraded woodlands
HOW HAVE                                a range of vegetation types that     in Victoria, poplar box woodland

THESE                                   occur in the region of NSW where
                                        clearing has been most prevalent.
                                                                             and tablelands woodland after a
                                                                             severe drought, to over 30/ha in
NUMBERS                                 Table 4 lists the results from a
                                                                             white box (E. albens) remnants
                                                                             and mixed open forest with many
BEEN                                    range of locations, mostly in        ironbarks near Bundarra. The
                                        NSW, where bird densities have
ESTIMATED?                              been estimated. These range from
                                                                             overall mean value is 20.7 birds/ha.

                                        the Tablelands to the eastern part   Therefore some 13 million
The estimates have been calculated
                                        of the Western Plains, and from      woodland and forest birds have
by multiplying a mean value
                                        south of the Murray in Victoria to   been or will be affected by the
for bird density by the number
                                        central Queensland. They include     clearing of all vegetation that
of hectares known to have been
                                        all of the major vegetation types    had been approved by the NSW
approved for clearing by the NSW
                                        in the region, from woodland to      Government from 1998 to 2005
                                        forest, and dominated by gums,       (640,000 x 20.7 = 13,250,000).
Birds occur at different densities in   boxes, stringybarks and ironbarks
                                        (Eucalyptus), as well as Callitris   The following table lists the results
different natural habitats, reaching
                                        and Casuarina. The density of        of estimates of bird densities from
their highest densities in wet
                                                                             a range of locations.
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
                                        © Klein Hubert

abundant as the density of trees
and shrubs declines. Consequently,

          Impacts of Land Clearing
 22            WWF-Australia
Habitat                      Region                 Density - Birds/ha                Reference                        Notes
     Coastal and Range                                            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            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            New England            18.2 breeding, 32.5 winter         Howe 1984 57                 Continuous forest
    woodland/ open forest
    Stringybark, gum, box            New England            16.1 breeding, 16.6 winter         Howe 1984 58                     Remnants
    woodland/ open forest
    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              ACT                             22.8              Er and Tidemann 1996
   Slopes Woodland and                                            Mean = 35.1
       Open Forest
         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                                           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.
     Eucalypt woodland,          Emerald, Queensland                     21.7               Woinarski et al. 2006          Average of 1973-6
          brigalow                                                                                                         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
          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.

                                                                                                                  Impacts of Land Clearing

3.4                                   of chaining of Allocasuarina
                                      shrubland in the Western Australian
                                                                             though some may stay for some
                                                                             time. We can only surmise what
WHAT                                  Wheatbelt. They compared sites         happens to birds that leave when        FUTURE
HAPPENS TO                            in uncleared shrubland, in chained
                                      but unburnt shrubland and in dead
                                                                             their home ranges are destroyed.
                                                                             Those that survive may move             IMPACTS OF
BIRDS WHEN                            stubble. Again, most woodland          into neighbouring habitat or cross      CLEARING
                                      birds declined or disappeared          open areas to other remnants. This
THEIR HABITAT                         after chaining, including two          may put them at greater risk of         OF NATIVE
IS CLEARED?                           species that are regarded as near
                                      threatened, the crested bellbird
                                                                             predation (see section 3.4). If they
                                                                             reach suitable habitat this is likely
Somewhat surprisingly, there          (Oreoica guttaralis) and the white-    to be occupied by, and defended         ON BIRD
seem to have been few studies on
the direct impact of vegetation
                                      browed babbler (Pomatostomus
                                      superciliosus). A few species
                                                                             by, other members of the same
                                                                             species. More likely, they will
clearance on birds. Birds are         became more common in the              have to settle for inferior habitat.    Whereas, there may be a direct
considerably more mobile than         chained site or stubble, for example   Although they may survive here          decline in the populations of
most mammals and reptiles, and        the willy wagtail (Rhipidura           for some time, they are unlikely        woodland birds due to loss of their
many will survive the immediate       leucophrys), and the Richard’s pipit   to breed successfully and replace       habitat, what is now becoming
clearing and even the burning         (Anthus novaeseelandiae) which         themselves before they die. This        clear is that for many species the
of wind-rowed vegetation. Eggs        only moved in after chaining.          could be because safe nest sites        decline in these populations is
and nestlings, and most recently                                             such as tree hollows or dense           actually far greater than simply the
                                      The longer term effects of clearing    shrubs are lacking or because
fledged young will probably die                                                                                       proportion of habitat that has been
                                      or chaining of woodland, burning       predators are more common. Also,
immediately. Ludwig et al. (2000)67                                                                                  lost.69 Clearing of native vegetation,
                                      of the debris and conversion to        important foraging sites or foods,
studied the impact of clearing                                                                                       especially in those regions where
                                      pasture of crops can be seen from      such as large tree trunks and nectar
of eucalypt woodlands near                                                                                           only a small proportion is left,
                                      examining birds in grassland (Table    may be scarce. Consequently, even
Emerald in central Queensland.                                                                                       will lead to remnants that are
                                      4). There are typically only one       though clearing may not kill the
Four of the six most common bird                                                                                     smaller, and more isolated from
                                      or two birds per ha in grassland,      majority of the woodland birds
species were significantly less                                                                                       each other, and also, because they
                                      i. e. 90-95% fewer than in intact      directly, over the longer term they
common in cleared land, and a                                                                                        have more edge are likely to be
                                      woodland. It should also be noted      will be lost from the landscape.
fifth probably was also negatively                                                                                    more degraded than continuous
                                      that these are mostly not woodland
affected by clearing. Only the                                                                                       woodland. Many woodland birds
                                      species, such as the pipit.
red-backed fairy-wren (Malurus                                                                                       avoid, or soon disappear from,
melanocephalus) increased in          Therefore, it is reasonable to                                                 smaller patches. Furthermore, they
cleared sites, because it prefers     conclude that almost all woodland                                              may be unwilling to disperse to
dense grassy habitat. Fulton and      birds either die or leave the                                                  isolated remnants. Most species
Majer (2006)68 looked at the effect   area after it has been cleared,                                                are absent from sites smaller than

         Impacts of Land Clearing
 24           WWF-Australia
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.

10 ha, but also quite a few species    90% of the native vegetation is
tend to be less frequent in sites      also clear in the Western Australian
less than 100 ha in area. There        Wheatbelt, and parts of Victoria.
are many reasons for this, and         Within NSW, critical levels of
they interact in complex ways.         habitat loss have been reached on
As well as the chance loss of          parts of the Tablelands. Although
small populations and difficulties      we may not yet have reached these
experienced in dispersing, birds in    critical levels throughout parts of
highly fragmented and degraded         the western slopes and adjoining
landscapes may suffer higher rates     plains, if we continue to clear at
of predation, especially on their      current rates, we shall soon reach
nests, and also competition from       the point at which many bird
aggressive species, such as noisy      populations move into regional
miners. We perhaps know best           decline and extinction. It is
what is happening in the case of the   imperative that we limit the amount
robins (see case study).               of clearing of native vegetation
                                       in NSW to prevent any further
Taken overall, the impact of           declines and extinctions of our
clearing and loss of a substantial     native birds. Unless we do this, any
proportion of the native vegetation    efforts to revegetate will be in vain.
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
                                                                                © WWF-Canon, Martin HARVEY

extent.70 The impact of removing

                                                                                                             Impacts of Land Clearing

Robins are a brightly coloured        robins to one patch, which had          Species                                  Decline in           Decline in
group of birds with two or three      lost the species in the early 1990s.                                             Australia              NSW
species often found in most           Some of the birds stayed and even
                                                                              Flame robin                                51%                    56%
wooded areas. They have been the      bred successfully, suggesting that
subject of many studies and these     the habitat was satisfactory for        Scarlet robin                              31%                    55%
together provide a clear indication   them, but that they had not been        Hooded robin                               27%                    41%
of how the loss, fragmentation        able to reach it. However, two birds    Jacky winter                               19%                    21%
and degradation of habitat can        travelled 7 km to the reintroduction
                                                                              Crested shrike-tit                         25%                    18%
affect our woodland birds. Birds      site from another patch unaided.
Australia conducted its second        So yellow robins can move               Dusky woodswallow                          28%                    41%
bird atlas from 1998 to 2002,         between remnants. Scarlet robins        White-browed woodswallow                   38%                    61%
some 20 years after the first atlas    also arrived in another site every
                                                                              Black-faced woodswallow                    36%                    65%
was completed.71 The atlases have     spring, probably from over 10 km
provided one of the few sources of    away. Further translocations have       Masked woodswallow                         22%                    46%
quantitative information on how       provided less clear-cut results.        Bush stone curlew                                                 63%
the abundance of some woodland        Few birds stayed in their new
                                                                              Table 5. Declines in recording rates of robins, and some other
birds has changed. The robins         locations for long, and in fact,        woodland birds, in Australia and NSW, between the first and
have fared worse than most, with      several translocated birds were         second bird atlas. 75
several species showing a decline     killed by predators, probably
in detection rate of 40% or more in   grey butcherbirds (Cracticus           currawongs (Strepera graculina),
                                                                                                                       scarcity of leaf litter and perhaps
NSW (Table 5).                        torquatus). So robins can disperse,    which have increased due to the
                                                                                                                       because there is less fallen timber.
                                      but it is a risky exercise, and        winter supply of exotic berries.
Studies in Western Australia,                                                                                          To some extent this is natural, and
                                      perhaps they often choose not to       However, there are plenty of other
Victoria and NSW have                                                                                                  to some extent because people have
                                      cross cleared country.                 nest predators from possums to
documented the loss of hooded                                                                                          collected firewood.
                                                                             shrike-thrushes and kookaburras.
and yellow robins from vegetation     Whether or not robins can disperse
                                                                                                                       So, robins are affected by a host of
remnants. The Armidale area           among vegetation remnants may          Even if they manage to escape
                                                                                                                       problems as they struggle to survive
provides an excellent example.        be irrelevant if there are too few     nest predators, robins may still
                                                                                                                       in their highly modified landscapes.
Hooded robins had gone from           young birds available to disperse.     struggle to feed their babies.
                                                                                                                       Quite likely other birds, which
three patches in the early 1980s,     Debus found that young fledged          Zanette found that there are fewer
                                                                                                                       have not been studied as well, are
and from three more by 2006.          from only about 9% of scarlet          ground invertebrates in some
                                                                                                                       influenced in the same way.
Eastern yellow robins in this time    robin nests in one woodland            smaller remnants, and chicks and
had vanished from two patches.        remnant, a figure very similar to       incubating females were fed less          It is noted that for almost all species
Although these are probably           that found by Robinson in more         often in such sites.74 Fertilised soils   the decline has been greater in NSW
random losses of very small           continuous woodland in southern        also may mean denser grass cover,         than in Australia as a whole.
populations – often single pairs,     NSW.73 Yellow robins were more         which can make capture of food
what is worrying is that they are     than twice as successful, but even     difficult for the pouncing robins.
not rescued by immigrants from        so they barely produced enough
other patches.                        young to replace local deaths,         Robins even in extensive eucalypt
                                      let alone provide new dispersers.      woodlands are found in much
So, are robins unable or unwilling    Scarlet robins only maintained         lower densities than in rainforest.
to disperse among isolated patches?   themselves due to the immigrants.      This is probably due to lower food
Debus72 moved eastern yellow          The main nest predators were pied      abundance, most likely due to the

          Impacts of Land Clearing
 26           WWF-Australia
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