LANDCLEARING IMPACTS OF - The Impacts of the Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales - WWF-Australia
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IMPACTS OF
LANDCLEARING
The Impacts of the Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales© Viewfinder
WHEN LAND
IS CLEARED,
EVERYTHING
THAT LIVES IN
IT IS KILLED.
– AUSTRALIA STATE OF THE ENVIRONMENT 2006
© WWF-Australia. All Rights Reserved.
WWF-Australia Head Office
GPO Box 528, Sydney, NSW, Australia 2001
Tel: +612 9281 5515 Fax: +612 9281 1060
wwf.org.au
Published February 2007 by WWF-Australia. Any reproduction in full or in part of this publication
must mention the title and credit the above-mentioned publisher as the copyright owner.
The opinions expressed in this publication are those of the author and do not necessarily reflect
the views of WWF.
For bibliographic purposes this report should be cited as:
Johnson, C., Cogger, H., Dickman, C. and Ford, H. 2007. Impacts of Landclearing; The
Impacts of Approved Clearing of Native Vegetation on Australian Wildlife in New South Wales.
WWF-Australia Report, WWF-Australia, Sydney.
Impacts of Land Clearing
b
ISBN: 1 921031 17 4
World Wide Fund forWWF-Australia
Nature ABN: 57 001 594 074CONTENTS
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
WWF-Australia
1ABOUT
THE
AUTHORS
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-AustraliaPROFESSOR HUGH FORD
BIRDS
Professor Hugh Ford is one of Australia’s most senior and respected bird
scientists. He has over 30 years of experience in the ecology, behaviour
and conservation of Australian birds, especially those of eucalypt forests
and woodlands.
Until recently, Professor Ford was Head of the School of Environmental
Sciences and Natural Resources Management, University of New England.
Professor Ford is the author of Ecology of Birds: An Australian Perspective.
He has edited two books on Australian birds and authored over 100 (book)
chapters and journal articles.
In 1980, Professor Ford and Dr Howe published a landmark study of
the long-term conservation status of birds in the Mount Lofty Ranges of
South Australia. Using island biogeography principles, the two scientists
predicted that of the original terrestrial bird fauna of about 120 species,
almost 50 would eventually become extinct. This was the first Australian
study alerting us to the problem of an ‘extinction debt’. The recently
started Mount Lofty Birds for Biodiversity Regional Recovery Project
aims to tackle this problem.
In 1993, Hugh Ford was awarded the Serventy Medal for ‘Outstanding
Services to Ornithology in the Australasian region’ by the Royal
Australasian Ornithologists Union.
Hugh Ford conducted a major project on the impact of habitat loss,
fragmentation and degradation on birds with Professor Harry Recher,
Dr Denis Saunders and Dr Geoff Barrett, which was supported by
WWF-Australia in the early 1990s.
Professor Ford is a Governor of WWF-Australia and was formerly
a member of WWF’s Scientific Advisory Panel. He is also a member
of the Research and Conservation Committee of Birds Australia.
Impacts of Land Clearing
WWF-Australia
3EXECUTIVE
SUMMARY
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-AustraliaAccording 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
WWF-Australia
51. BACKGROUND
1.1 In 2003, the WWF-Australia
report, Impacts of Land Clearing
habitats for short-term gains and
reduced their diversity, adaptability
1.2
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-AustraliaWhen 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
WWF-Australia
71. BACKGROUND
1.3
NATIVE VEGETATION LOSS IN NSW
NSW covers some 800,000 square kilometres of south eastern Australia.
It is a topographically complex region that includes more than one quarter
of the nation’s plant species and encompasses almost all of the major
environments represented in Australia.
NSW has already lost well over half of its native vegetation. Since 1788,
at least 61% of the original native vegetation of NSW has been cleared,
thinned or substantially or significantly disturbed. This figure exceeds
90 per cent in the case of some types of native environments such as the
south east grassy forests.15
The following map depicts the existing extent of native vegetation in NSW
in 2005.
Figure 1. Map of existing native
vegetation in NSW, 200516
© WWF Canon / Michel DEPRAZ
Rainforests
Wet sclerophyll forests (shrubby subformation)
Wet sclerophyll forests (grassy subformation)
Grassy woodlands
Grasslands
Dry sclerophyll forests (shrub/grass subformation)
Dry sclerophyll forests (shrubby subformation)
Heathlands
Alpine complex
Freshwater wetlands
Forested wetlands
Saline wetlands
Semi-arid woodlands (grassy subformation)
Semi-arid woodlands (shrubby subformation)
Arid shrublands (chenopod subformation)
Arid shrublands (acacia subformation)
Impacts of Land Clearing
8
Cleared land
WWF-AustraliaNSW 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
WWF-Australia
91. BACKGROUND
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.
OF NATIVE
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
process
despite the fact that NSW wildlife
is already under siege. Mammals 57 49 86%
(terrestrial)
In NSW, 315 animal species or Birds 88 72 82%
populations are listed as threatened (non-marine,
with Statewide extinction.22 This not offshore)
comprises:
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-Australia1.5
METHODOLOGY
• Information on native vegetation change
The calculations in this report are based on the known record of approved
clearing of native vegetation between 1998 and 2005 published by the
NSW Auditor-General in the 2006 report, Regulating the Clearing of
Native Vegetation. Follow-up of 2002 Performance Audit. 25
The figures reported by the Auditor-General are not a complete record
of the clearing of native vegetation in NSW for the subject time period.
Instead, the Auditor-General’s report figures comprise only the area subject
to approvals under the previously applicable legislation (being the Native
Vegetation Conservation Act 1997)26 and an estimate of illegal clearing
in 2005.
• Calculation of wildlife impacts
Given Australia’s megadiversity of species and our comparatively small
human population and research base, the density (ie number of individuals
in a given area) of relatively few species has been determined with
precision. In addition, the number of different species, or species richness,
occurring in a given area is not known in great detail for many habitats.
Estimates of these values must necessarily be extrapolated from a relatively
small number of detailed studies. Therefore the authors have deliberately
employed highly conservative estimates in making their calculations. The
true mortality is likely to be substantially higher than those estimated in
this report.
© Bruce Thomson, auswildlife.com
Impacts of Land Clearing
WWF-Australia
112. MAMMALS
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
2.2
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-AustraliaIt 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
WWF-Australia
132. MAMMALS
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-AustraliaMammal 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. MAMMALS
2.3 • The densities of several
common species, such as the
this category, the planigales,
Planigale gilesi and
2.4
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
CLEARED?
• 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-AustraliaWithin 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
WWF-Australia
172.6 CASE STUDIES:
THE EFFECTS
OF CLEARING
ON POSSUMS
AND GLIDERS
1
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
2
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
WWF-Australia
193. BIRDS
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-AustraliaIt 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
WWF-Australia
213. BIRDS
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
Government.48
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-AustraliaHabitat Region Density - Birds/ha Reference Notes
Coastal and Range Mean = 30.4
Forests
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
2003
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
box
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
Scrub
Box, gum, pine woodlands Northern Plains, Victoria 8.2 Antos and Bennett 2004
Box, gum, pine Murray Plains 19.7 Oliver and Parker 2006 Mature only – excl.
replanted
Eucalypt woodland, 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
Trees
Rainforest Mean = 33.0
Rainforest Coastal NSW 33.0 Shields et al. 1985 66
Table 4: Estimates of the density of birds from a variety of habitats.
Impacts of Land Clearing
WWF-Australia
233. BIRDS
3.4 of chaining of Allocasuarina
shrubland in the Western Australian
though some may stay for some
time. We can only surmise what
3.5
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
VEGETATION
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
POPULATIONS
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-AustraliaIt 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
WWF-Australia
253.6 CASE STUDY:
WHAT IS
HAPPENING
TO ROBINS?
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-AustraliaYou can also read
