An Australian perspective on rewilding
ın F. Sweeney ,1∗John Turnbull,2Menna Jones,3Mike Letnic,4Thomas M. Newsome,5
and Andy Sharp6
1National Parks Association of New South Wales, Pyrmont, NSW, 2009, Australia
2Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales,
Sydney, NSW, 2052, Australia
3School of Biological Sciences, University of Tasmania, Hobart, TAS, 7001, Australia
4Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney,
NSW, 2052, Australia
5School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
6Natural Resources Northern and Yorke, Clare, SA, 5453, Australia
Abstract: Rewilding is increasingly recognized as a conservation tool but is often context specific, which
inhibits broad application. Rewilding in Australia seeks to enhance ecosystem function and promote self-
sustaining ecosystems. An absence of large-bodied native herbivores means trophic rewilding in mainland
Australia has focused on the restoration of functions provided by apex predators and small mammals.
Because of the pervasive influence of introduced mesopredators, predator-proof fences, and establishment of
populations on predator-free islands are common rewilding approaches. This sets Australian rewilding apart
from most jurisdictions and provides globally relevant insights but presents challenges to restoring function
to broader landscapes. Passive rewilding is of limited utility in arid zones. Although increasing habitat extent
and quality in mesic coastal areas may work, it will likely be necessary to undertake active management.
Because much of Australia’s population is in urban areas, rewilding efforts must include urban areas to
maximize effectiveness. Thus rewilding is not synonymous with wilderness and can occur over multiple
scales. Rewilding efforts must recognize human effects on other species and benefit both nature and humans.
Rewilding in Australia requires development of a shared vision and strategy and proof-of-concept projects to
demonstrate the benefits. The repackaging of existing conservation activities as rewilding may confuse and
undermine the success of rewilding programs and should be avoided. As elsewhere, rewilding in Australia
should be viewed as an important conservation tool.
Keywords: apex predator, conservation fencing, critical weight range mammals, ecosystem function, keystone
species, nature-based solutions, people and conservation, policy
Una Perspectiva Australiana del Proceso de Resilvestrar
Resumen: El proceso de resilvestrar es reconocido cada vez m´
as como una herramienta de conservaci´
pero con frecuencia depende del contexto ambiental, lo que inhibe su aplicaci´
on generalizada. En Australia,
el proceso de resilvestrar busca mejorar la funci´
on ambiental y promover los ecosistemas auto-sustentables.
Una ausencia de herb´
ıvoros nativos corpulentos significa que el resilvestreo tr´
ofico en la isla principal de
Australia se ha enfocado en la restauraci´
on de las funciones que proporcionan los superdepredadores y
nos. Debido a la influencia generalizada de los mesodepredadores introducidos, los
cercos contra depredadores y el establecimiento de poblaciones en islas libres de depredadores son estrategias
comunes de resilvestreo. Esto coloca al resilvestreo australiano aparte del que ocurre en muchas jurisdicciones
y proporciona informaci´
on relevante a nivel mundial, pero presenta retos para la restauraci´
on de la funci´
en paisajes m´
as amplios. El resilvestreo pasivo es de utilidad limitada en las zonas ´
aridas. Aunque el aumento
de la extensi´
on del h´
abitat y la calidad en las ´
areas meso-costeras puede funcionar, probablemente sea
Article impact statement: Rewilding in Australia seeks to enhance ecosystem function and promote self-sustaining ecosystems.
Paper submitted October 24, 2017; revised manuscript accepted November 22, 2018.
Conservation Biology, Volume 00, No. 0, 1–9
2019 Society for Conservation Biology
necesario emprender un manejo activo. Ya que la mayor´
ıa de la poblaci´
on de Australia se encuentra en
areas urbanas, los esfuerzos de resilvestreo deben incluir a las ´
areas urbanas para maximizar su efectividad.
Por lo tanto, el resilvestreo no es sin´
onimo de la naturaleza y puede ocurrir en m´
ultiples escalas. Los esfuerzos
de resilvestreo deben reconocer los efectos que los humanos tienen sobre otras especies y deben beneficiar a
la naturaleza y a las personas. El resilvestreo en Australia requiere del desarrollo de una visi´
y de proyectos con prueba de concepto para demostrar sus beneficios. La reinvenci´
on de las actividades de
on existentes como resilvestreo podr´
ıa confundir y debilitar el ´
exito de los programas de resilvestreo,
por lo que deber´
ıa evitarse. Como en todos lados, el proceso de resilvestrar en Australia deber´
ıa verse como
una herramienta importante de conservaci´
Palabras Clave: cercado de conservaci´
on, especies clave, funci´
on ambiental, mam´
ıferos del rango de peso
ıtico, personas y conservaci´
ıtica, soluciones basadas en la naturaleza
Perceptions of Rewilding
The success of rewilding in capturing public imagi-
nation stems from its framing as a positive activity
(Monbiot 2013). The public appeal of rewilding helps
explain why nongovernmental organizations (NGOs) are
active in rewilding (e.g., Australian Wildlife Conservancy,
Greening Australia, Conservation Volunteers Australia).
Governments too embrace rewilding (e.g., European
Commission financially supports Rewilding Europe; state
and federal Australian Government agencies practice or
intend to practice rewilding).
There is a growing consensus that rewilding should
focus on restoring ecosystem processes and species
interactions to promote complexity and self-sustaining
andez et al. 2017; Pettorelli et al. 2018),
although several definitions exist (Jørgensen 2015;
Pettorelli et al. 2018). Trophic rewilding usually refers
to environmental change driven by strongly interacting
e et al. 2003). Rewilding can therefore
include restoration of predatory interactions that trigger
trophic cascades and ultimately affect vegetation (Ripple
& Beschta 2007), but could also encompass restoration
of the ecological functions of ecosystem engineers
such as beavers (Castor spp.) (Law et al. 2016), large-
bodied herbivores (Ripple et al. 2015), and granivores
(Mills & Letnic 2018). In passive rewilding vegetation
encroachment (e.g., via abandonment of pastoral land)
drives changes in fauna and flora species composition
and biodiversity (Regos et al. 2016).
Rewilding means different things in different places
(Seddon et al. 2014), and lack of a fixed definition
(Jørgensen 2015) makes setting goals and evaluating suc-
cess difficult (Nogu´
es-Bravo et al. 2016). Questions exist
as to what ecological state, if any, rewilding efforts should
seek to replicate (Corlett 2016), and empirical evidence
that rewilding works is scarce (Nogu´
es-Bravo et al. 2016).
Some argue trophic rewilding distracts from more urgent
conservation issues (Rubenstein & Rubenstein 2016),
others argue rewilding helps reverse declines of biodi-
versity and ecosystem function in a human-dominated
world (Svenning et al. 2016). Whether rewilding is
relevant to introduction of non-native species outside
their range is unclear (Bradshaw et al. 2006), and intro-
duction of ecological surrogates is controversial (Donlan
In Australia support for rewilding stems from increas-
ing threats to biodiversity (Cresswell & Murphy 2017),
the need for novel approaches to reverse species’ de-
cline, and its complementarity with other conservation
initiatives. However, hurdles remain to successful, broad
application of rewilding in Australia. We considered how
rewilding experiences and approaches in other juris-
dictions are relevant to Australia; compared Australian
rewilding approaches with those used in other parts of
the world; considered future directions for rewilding in
Volume 00, No. 0, 2019
Sweeney et al. 3
Australia; and identified lessons learned in Australia that
are applicable elsewhere.
Opportunities and Limitations of Trophic
Rewilding in Australia
Restoring predator populations that have undergone
range contractions may be particularly important in Aus-
tralian rewilding. Top-down control by dingoes (Canis
dingo), mainland Australia’s largest terrestrial carnivore,
for instance, is a potentially cost-effective mechanism
to suppress or alter the behavior of introduced invasive
mesopredators, such as the red fox (Vulpes vulpes)and
feral cat (Felis catus) (Brook et al. 2012; Letnic et al.
2012). Such top-down control may also enable improved
coexistence of native and non-native species (Wallach
et al. 2015) and reduce overabundant small- and medium-
bodied native and invasive herbivores (Letnic et al. 2012;
Morris & Letnic 2017), sometimes leading to positive
economic outcomes for farmers (Prowse et al. 2014).
The reintroduction of Tasmanian devils (Sarcophilus har-
risii) to mainland Australia may lower red fox and feral
cat abundance, influence trophic cascades, and benefit
small mammals (Hollings et al. 2014, 2016), although not
all species (Hunter et al. 2015).
Increases in large carnivore populations in Europe
(Chapron et al. 2014) raise concern that there is
insufficient space for large predators and humans to coex-
ist (Rubenstein & Rubenstein 2016). However, mainland
Australia is sparsely populated and Tasmanian devils and
humans coexist in Tasmania, where the species is extant.
Other objections to restoring predators relate to human
safety and livestock depredation (Fleming et al. 2012).
Human injuries from Tasmanian devils or dingoes are ex-
tremely rare, but dingoes and devils could harm livestock,
particularly sheep (Jones et al. 2003; Fleming et al. 2012).
As in parts of Europe, where wolves (Canis lupus)are
culled, societal values will be the primary determinant to
the success of trophic rewilding of predators in Australia.
Australian critical weight range (CWR) mammals
(ground-dwelling species from 35 g to 5.5 kg vulnerable
to extinction; [Burbidge & McKenzie 1989]) are suscep-
tible to predation by red foxes and feral cats because
they lack appropriate antipredator responses (Moseby
et al. 2016). Since European colonization, some ecosys-
tem functions and processes have been reduced or elimi-
nated because of mammal extinctions and range contrac-
tions (Bilney et al. 2010; Fleming et al. 2014; Hayward
et al. 2016) (Fig. 1). Thus, CWR mammals are a priority
for conservation, but ineffective control of red foxes and
feral cats, habitat loss, and altered fire regimes remain key
challenges to trophic rewilding of small mammals (Bilney
et al. 2010; Woinarski et al. 2015).
In Europe, Asia, and North America reintroducing
large-bodied (>100 kg) herbivores (or surrogates) is part
of trophic rewilding. Australia lacks comparable native
herbivores but has horses (Equus caballus), donkeys
(Equus asinus), water buffalos (Bubalus bubalis), and
camels (Camelus dromedaries). These were all intro-
duced and have effects on ecosystems that are gener-
ally perceived as negative. Ecological control of these
species cannot be achieved currently due to a lack of
native predators of sufficient size to exert top-down con-
trol (Forsyth et al. 2018). Introducing surrogates of long-
extinct predators is, in the short term at least, unrealistic
in Australia due to intolerance and persecution of existing
predators. The broader effects of such reintroductions on
other species are also unknown.
Opportunities and Limitations of Passive Rewilding
Passive rewilding (broadly letting nature take its course)
in Europe has yielded conservation benefits (Regos et al.
2016), and benefits would likely accrue from passive
rewilding in parts of Australia. Australia has lost approxi-
mately 40% of its forest cover, and much of the remainder
is highly fragmented (Bradshaw 2012) or was previously
logged (Hobday & McDonald 2014). Passive rewilding
would increase forest cover and the density of large trees
and the biodiversity they support (Lindenmayer et al.
2014). The loss of hollow-bearing trees is a threat to many
forest-dependent mammals (Woinarski et al. 2014) and
birds (BirdLife Australia & Australian Government Depart-
ment of Environment 2015) because Australia possesses
a disproportionate number of species that use hollows
(Gibbons & Lindenmayer 2002).
However, complex interactions between disturbance
(e.g., logging and fragmentation), invasive plants (Lan-
tana camera), and despotic bell miners (Manorina
melanophrys) have resulted in a phenomenon called bell
miner-associated dieback affecting localized but exten-
sive areas of eucalypt forest (Silver & Carnegie 2017).
Despotic noisy miners (M. melanocephala)stronglyand
negatively affect bird species richness and abundance
in woodland ecosystems (Thomson et al. 2015). Manage-
ment intervention is likely to be required in both systems,
limiting the application of passive rewilding.
Many forest ecosystems in Australia are fire prone,
and historic Aboriginal fire management likely influenced
forest development. Fire management following forest
restoration may be necessary to protect fire-sensitive
ecosystems, such as rainforests, or for hazard reduction.
Fire is also likely to be a management concern in passively
regenerating Mediterranean vegetation types in south-
ern Europe. As climate change alters the profitability of
arid-zone pastoralism, some of these lands may become
available for conservation. However, passive rewilding in
Australia’s arid interior, which retains extensive tracts of
native vegetation, may not stop biodiversity declines if
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Figure 1. (a) Impacts of reduced digging on ecosystem function, (b) consequences of the loss of ecosystem function,
(c) impacts of reduced predation on ecosystem function, and (d) consequences of the loss of ecosystem function.
introduced mesopredators remain present or if intro-
duced weeds (e.g., buffel grass [Cenchrus ciliaris]) prolif-
erate and alter fire regimes. Efforts to restore populations
of native fauna will therefore likely need to be accompa-
nied by pest and weed control to help shift the ecosystem
to a preferred state.
Restoring ecosystem function is no less urgent in
marine ecosystems; trophic cascades commonly occur
(Estes et al. 2011) and predatory fish biomass has been
extensively depleted (Christensen et al. 2014). The
recovery of large predatory fish can occur with minimal
human intervention, through the creation of marine
protected areas (MPAs), but to maximize effectiveness,
MPAs must be large, no take, long established, well
enforced, and isolated by deep water or sand (Edgar et al.
2014). In marine systems, widespread loss of habitat-
forming species, such as oysters and corals, and the
facilitation cascades they support simplifies ecosystems
and threatens biodiversity conservation, and their
restoration may thus be construed as rewilding (Thomsen
et al. 2010; Marzinelli et al. 2016). The restoration of such
structural elements need not be confined to MPAs but
is likely to be promoted within them via restrictions on
fishing and physical damage from human infrastructure.
Fenced Exclosures and Rewilding
Australia’s fauna has been devastated by introduced novel
predators due to its long history of evolutionary isolation
(Medina et al. 2011). In Australia fencing is used to ex-
Figure 2. Fenced exclosures, such as at Arid Recovery,
from which red foxes and feral cats are eradicated
achieve some rewilding objectives (photo by Charlotte
clude introduced mesopredators (red foxes and feral cats)
and lower mortality of predator-na¨
ıve CWR mammals.
Fencing in Africa, in contrast, is used to separate humans
and large predators and in Europe to maintain predator
density in rewilding efforts (Bull et al. 2018). Predator-
proof exclosures are also used in New Zealand to provide
havens for birds, reptiles, and invertebrates threatened by
introduced predators (Pech & Maitland 2016).
Fenced exclosures (Fig. 2) have been used success-
fully in Australia to protect threatened species and in-
crease their populations (Moseby et al. 2009). Current
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Sweeney et al. 5
exclosures range from small to reasonably large (123 km2,
Arid Recovery) and a 1450-km2exclosure is proposed
for Yorke Peninsula in South Australia. Recovery of small
mammal populations influences fungi (Clarke et al. 2015)
and termite assemblages (Coggan et al. 2016), soil prop-
erties (Martin 2003; James et al. 2009), seed dispersal,
and shrub recruitment (Mills et al. 2017). In this regard,
fenced exclosures achieve rewilding objectives at least
for some functions driven by smaller species. Only the
largest exclosures can achieve rewilding of devils and
dingoes (Moseby et al. 2018), and these would need to be
even larger to host self-sustaining populations or multiple
groups of devils and dingos.
Fences are ultimately inconsistent with the goal of rein-
stating self-sustaining ecosystems due to the maintenance
requirements of fences, the need for managed migration
between metapopulations, and the disruptions to ecosys-
tem processes and habitat degradation that may arise with
increasing animal populations contained within fences
(Hayward & Kerley 2009). Without the reintroduction of
native predators, fenced exclosures may exacerbate the
problem of prey na¨
e (Moseby et al. 2016). Fences
may therefore be best viewed as a starting point on a
rewilding continuum toward landscape-scale rewilding
that would be achieved in theory through restoration of
native predator populations, the use of livestock guardian
animals, shifts in pastoral practices, financial incentives to
farmers (Van Eeden et al. 2017), and novel means, such as
promoting conditions for native prey species to coevolve
with introduced predators (Moseby et al. 2016). Concur-
rent efforts to improve outcomes on a landscape scale are
necessary to restore self-sustaining ecosystems and avoid
small mammals being confined to fenced exclosures and
loss of their functions in the broader landscape.
Australian NGO and academic sectors enthusiastically
support Tasmanian devil reintroductions to the Australian
mainland (Ritchie et al. 2012) (Supporting Information)
to improve ecosystem function. Devils were extirpated
from mainland Australia 3000 years ago (White et al.
2018). In the absence of a demonstrated broader func-
tional role, assisted colonization of species as a global
conservation tool (Bradshaw et al. 2006) does not fit
rewilding goals. For example, proposals by the Australian
Rhino Project to bring black (Diceros bicornis)andwhite
(Ceratotherium simum) rhinoceroses to Australia have
not focused on the restoration of ecosystem processes,
but rather on conservation of these species.
People and Rewilding
One criticism of rewilding has been a perceived aim of
excluding human involvement with and influence on na-
ture and ecosystems (Jørgensen 2015). Some rewilding
efforts in Europe do seek to reduce human influence
on modified agricultural landscapes (Ceaușu et al. 2015).
But benefits can accrue to humans from rewilding. These
may accrue directly, such as income derived from wildlife
tourism and dingoes increasing profitability of farming
in some circumstances (Prowse et al. 2014; Johnson &
Wallach 2016), or indirectly through ecosystem services.
For example, restoring forest ecosystems in catchments
could reduce flood risk and provide clean water. Rewild-
ing thus shares similarities with nature-based solutions to
social problems that deliver both biodiversity and human
over et al. 2017).
The importance of community involvement, particu-
larly in trophic rewilding, cannot be overstated. Predator
conservation efforts are likely to be opposed initially by
some, and social impacts of rewilding should be assessed
and made clear (Pettorelli et al. 2018). Predator-friendly
farming, designed to integrate socioeconomic and envi-
ronmental outcomes (Johnson & Wallach 2016), is used
in North America and Africa and may help overcome
aversions to predators in Australia too.
Globally, rewilding is synonymous with large, near-
continental scale projects. Yet in Australia, approximately
70% of the human population live in cities and 85% live
in urban areas. Urban rewilding is therefore a high pri-
ority in Australia to demonstrate tangible outcomes and
increase engagement with nature (Jepson 2016). Urban
programs, such as reintroductions of pollinators, reptiles
or small mammals accepted by humans, should occur
alongside initiatives in rural landscapes with the dual aim
of increasing ecosystem function and engaging the pub-
lic in conservation (Watson & Watson 2015). Rewilding
should therefore occur at multiple spatial scales (Fig. 3)
and seek to increase nonhuman autonomy, rather than
spatially separate humans and nonhumans (Prior & Ward
2016). In urban areas, rewilding will necessarily become a
compromise between restoring ecosystem function and
raising public awareness through species tolerated by
humans. There may also be a need to reduce the key
threats that led to the loss of species in the first place,
which sometimes may not be achievable.
Location is an important consideration in rewild-
ing because some areas and landscapes are more eco-
logically and socially suitable than others (Supporting
Information). In Europe a network of experimental sites
has been proposed to identify priority rewilding areas
(Jepson 2016), which could offer a model for Australia.
Locating rewilding initiatives where they have a good
chance of success and where economic benefits can ac-
crue may provide proof of concept and raise the profile of
rewilding. Success may be more readily achieved in areas
where there are ongoing conservation programs run by
local communities. Indigenous owned and managed land
in Australia offers great potential in this regard, especially
where there are established conservation programs or
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Figure 3. Scales at which rewilding is relevant: (a) wisent (Bison bonasus), a large-bodied herbivore, has a large
trophic influence over landscape scales, (b) beaver dams affect biodiversity at regional and local scales, and (c)
pygmy possum (Cercartetus spp.) have local effects in their home ranges of <1ha.
voluntary conservation agreements such as indigenous
protected areas. Indigenous land covers 52% of the coun-
try, and around three-quarters of Australia’s threatened
terrestrial or freshwater vertebrates occur on these lands
(Renwick et al. 2017).
Restoring Processes Rather than Historic States
Rewilding’s focus on ecological processes means success
should be measured by the degree to which management
actions result in the restoration of desired processes. Pos-
itive relationships between biodiversity and ecosystem
function (Cardinale et al. 2012) suggest restoration of
ecological processes may maintain biodiversity. A pro-
cess focus recognizes that ecosystems are dynamic and
therefore do not have a single historic state (Rohwer &
Marris 2016). A reintroduction of beavers (Castor fiber)
confirmed predictions that restored processes would in-
crease biodiversity (Law et al. 2016; Stringer & Gaywood
2016; Law et al. 2017). The restoration of pre-European
landscapes and species assemblages in Australia is in most
cases unachievable due to extinctions and the difficulties
of removing invasive species. Rewilding should therefore
consider contemporary patterns and processes, including
widespread human settlement, and the effects of human
activities and climate change on abundances and distri-
butions of species.
Current conservation policy in Australia tends to focus on
species-specific or ecological-community-specific threat
reduction that targets species and ecosystems listed as
threatened by experts. Two projects, Gondwana Link
and the Great Eastern Ranges Initiative, seek to enhance
connectivity on the continental scale, and connectivity
is often an aim of conservation strategies. Strategies also
regularly recognize the need to build human appreciation
of nature. The National Reserve System seeks to achieve
comprehensive, adequate, and representative protection
of ecosystems at a bioregional level.
Rewilding should not replace these approaches, but
could be complementary and assist in meeting goals. For
example, explicitly considering maintenance of identi-
fied ecosystem processes could inform reserve selection
and better identify priorities for private land conserva-
tion. Some agricultural policies (e.g., lethal control of din-
goes and land clearing) are contradictory to both conser-
vation and rewilding goals and will require policy shifts.
Lessons from Rewilding in Australia
Although rewilding in Australia differs from rewilding
on continental landmasses, primarily due to the impact
of introduced mesopredators, there are lessons to be
learned from Australia. For example, the focus on re-
constructing all components of food webs, starting with
small consumers such as small mammals and birds, is
underdeveloped globally. Predator exclosures are used
to good effect in Australia and New Zealand and may
facilitate rewilding by promoting persistence of smaller
species affected by introduced predators.
The development of shared goals and strategies for
rewilding in Australia would provide more clarity of pur-
pose and allow evaluation of success and would clearly
signal to policy makers and funding bodies what con-
stitutes rewilding and help avoid rewilding becoming a
rehash of existing activities, which risks eroding pub-
lic interest. For example, the term rewilding is used
in the context of fairy bell-flower (Homoranthus spp.)
conservation to mean reintroductions following seed col-
lections, with no reference to broader ecosystem bene-
fits (Department of the Environment and Energy 2017).
Translocations of species for conservation purposes dif-
fer from translocations of species for that species to per-
form an ecological role (rewilding) (Seddon et al. 2014)
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Sweeney et al. 7
Developing projects to demonstrate proof of concept
that integrate communities and research into rewilding
actions (Supporting Information) would help answer in-
ternational calls for more evidence (Nogu´
es-Bravo et al.
2016; Svenning et al. 2016). Projects in urban areas
designed to deliver outcomes for humans and nature
and high-profile, achievable landscape-scale rewilding are
clear priorities. Differences among arid, Mediterranean,
and mesic Australia mean rewilding needs to be tailored
to location. Passive rewilding may play a greater role in
coastal areas, but a complete absence of management
is likely impossible. However, the important ecological
role of CWR mammals in Australian ecosystems, and their
widespread declines (Fig. 1), means restoration of their
populations remains a high priority throughout Australia.
In New Zealand, restoring the ecological functions of
bird pollinators that have declined because of predation
by mammalian predators has been identified as a priority
(Anderson et al. 2011). To our knowledge, few rewilding
efforts in other jurisdictions focus on restoring ecological
functions of small consumers.
Engaging communities should be a fundamental
component of rewilding efforts and could be aided by
focusing initially on species and functions most likely
to be accepted by humans. This approach would help
develop societal support for rewilding before tackling
controversial activities, such as reintroduction of preda-
tors. For trophic rewilding in Australia, a concerted effort
is needed to shift current attitudes—and policy—from
one of predator persecution to one of tolerance. Trial
reintroductions of Tasmanian devils to mainland Australia
(Supporting Information) have yet to gain political
support. In areas of high ecological value, caution is
warranted. But in highly modified areas, more ambitious
policies should be pursued to accelerate rewilding. For
example, there are large parks in many Australian cities
where small mammals could be readily reintroduced and
passive rewilding promoted.
The popular appeal of rewilding means it should not
be dismissed as a conservation tool. For rewilding to be
effective, it is important that it not be used to rebrand
existing activities. Provided use of the term rewilding is
restricted to conservation actions that fit the definition,
it could greatly increase the profile of conservation and
wild nature in general.
Insights in this article resulted from a forum supported
financially by Taronga Conservation Society, the National
Parks Association of NSW, FAUNA Research Alliance, and
Conservation Volunteers Australia. We thank staff and
volunteers from the National Parks Association of NSW
and all participants for the productive and collaborative
manner in which they engaged in the process. Several
reviewers provided valuable feedback on earlier drafts of
Forum participants (Appendix S1), methods (Ap-
pendix S2), and results (Appendix S3) are available on-
line. The authors are solely responsible for the content
and functionality of these materials. Queries (other than
absence of the material) should be directed to the corre-
Anderson SH, Kelly D, Ladley JJ, Molloy S, Terry J. 2011. Cascading
effects of bird functional extinction reduce pollination and plant
density. Science 331:1068–1071.
Bilney RJ, Cooke R, White JG. 2010. Underestimated and severe: Small
mammal decline from the forests of south-eastern Australia since
European settlement, as revealed by a top-order predator. Biological
BirdLife Australia & Australian Government Department of Environ-
ment. 2015. The state of Australia’s birds 2015: headline trends
for terrestrial birds. Birdlife International, Cambridge, United
Kingdom. Available from http://www.birdlife.org.au/documents/
SOAB-2015.pdf (accessed February 2018).
Bradshaw CJ. 2012. Little left to lose: deforestation and forest degra-
dation in Australia since European colonization. Journal of Plant
Bradshaw CJA, Isagi Y, Kaneko S, Bowman DMJS, Brook BW. 2006.
Conservation value of non-native Banteng in Northern Australia.
Conservation Biology 20:1306–1311.
Brook LA, Johnson CN, Ritchie EG. 2012. Effects of predator control
on behaviour of an apex predator and indirect consequences for
mesopredator suppression. Journal of Applied Ecology 49:1278–
Bull JW, Ejrnæs R, Macdonald DW, Svenning JC, Sandom CJ. 2018.
Fences can support restoration of human-dominated ecosys-
tems when rewilding with large predators. Restoration Ecology
Burbidge AA, McKenzie NL. 1989. Patterns in the modern decline of
western Australia’s vertebrate fauna: causes and conservation impli-
cations. Biological Conservation 50:143–198.
Cardinale BJ, et al. 2012. Biodiversity loss and its impact on humanity.
Ceaușu S, Hofmann M, Navarro LM, Carver S, Verburg PH, Pereira HM.
2015. Mapping opportunities and challenges for rewilding in Eu-
rope. Conservation Biology 29:1017–1027.
Chapron G, et al. 2014. Recovery of large carnivores in Europe’s modern
human-dominated landscapes. Science 346:1517–1519.
Christensen V, Coll M, Piroddi C, Steenbeek J, Buszowski J, Pauly D.
2014. A century of fish biomass decline in the ocean. Marine Ecology
Progress Series 512:155–166.
Clarke LJ, Weyrich LS, Cooper A. 2015. Reintroduction of locally extinct
vertebrates impacts arid soil fungal communities. Molecular Ecology
Coggan NV, Hayward MW, Gibb H. 2016. Termite activity and de-
composition are influenced by digging mammal reintroductions
along an aridity gradient. Journal of Arid Environments 133:
Corlett RT. 2016. Restoration, reintroduction, and rewilding in a chang-
ing world. Trends in Ecology & Evolution 31:453–462.
Volume 00, No. 0, 2019
Cresswell ID, Murphy HT. 2017. Australia state of the environment
2016: biodiversity. Australian Government Minister for the Environ-
ment and Energy, Canberra, Australia. Available from https://soe.
nch-version2-24feb17.pdf?v=1488792935 (accessed March 2017).
Department of the Environment and Energy (DEE). 2017. Threatened
species prospectus. DEE, Canberra, Australia. Available from http://
(accessed March 2017).
Donlan J. 2005. Re-wilding North America. Nature 436:913–914.
Edgar GJ, et al. 2014. Global conservation outcomes depend on marine
protected areas with five key features. Nature 506:216–220.
Estes JA, et al. 2011. Trophic downgrading of planet earth. Science
andez N, Navarro LM, Pereira HM. 2017. Rewilding: a call for
boosting ecological complexity in conservation. Conservation Let-
Fleming PA, Anderson H, Prendergast AS, Bretz MR, Valentine LE, Hardy
GES. 2014. Is the loss of Australian digging mammals contribut-
ing to a deterioration in ecosystem function? Mammal Review 44:
Fleming PJS, Allen BL, Ballard G-A. 2012. Seven considerations about
dingoes as biodiversity engineers: the socioecological niches of dogs
in Australia. Australian Mammalogy 34:119–131.
Forsyth D, Latham D, Davis N, Caley P, Letnic M, Moloney P, Wood-
ford L, Woolnough A. 2018. Interactions between dingoes and
introduced wild ungulates: concepts, evidence and knowledge
gaps. Australian Mammalogy 41:12–26. https://doi.org/10.1071/
Gibbons P, Lindenmayer DB. 2002. Tree hollows and wildlife conserva-
tion in Australia. CSIRO, Collingwood, Australia.
Hayward MW, Kerley GIH. 2009. Fencing for conservation: Restriction
of evolutionary potential or a riposte to threatening processes? Bio-
logical Conservation 142:1–13.
Hayward MW, Ward-Fear G, L’Hotellier F, Herman K, Kabat AP, Gibbons
JP. 2016. Could biodiversity loss have increased Australia’s bushfire
threat? Animal Conservation 19:490–497.
Hobday AJ, McDonald J. 2014. Environmental issues in Australia. Annual
Review of Environment and Resources 39:1–28.
Hollings T, Jones M, Mooney N, McCallum H. 2014. Trophic cascades
following the disease-induced decline of an apex predator, the Tas-
manian devil. Conservation Biology 28:63–75.
Hollings T, Jones M, Mooney N, McCallum H. 2016. Disease-induced
decline of an apex predator drives invasive dominated states and
threatens biodiversity. Ecology 97:394–405.
Hunter DO, Britz T, Jones M, Letnic M. 2015. Reintroduction of Tas-
manian devils to mainland Australia can restore top-down control
in ecosystems where dingoes have been extirpated. Biological Con-
James AI, Eldridge DJ, Hill BM. 2009. Foraging animals create fertile
patches in an Australian desert shrubland. Ecography 32:723–732.
Jepson P. 2016. A rewilding agenda for Europe: creating a net-
work of experimental reserves. Ecography 39 https://doi.org/
Johnson CN, Wallach AD. 2016. The virtuous circle: predator-friendly
farming and ecological restoration in Australia. Restoration Ecology
Jones ME, Oakwood M, Belcher C, Morris K, Murray AJ, Woolley PA,
Firestone KB, Johnson B, Burnett S. 2003. Carnivore concerns: prob-
lems, issues and solutions for conserving Australasia’s marsupial
carnivores. Pages 418–430 in Jones ME, Dickman CR, Archer M, edi-
tors. Predators with pouches: the biology of carnivorous marsupials.
CSIRO Publishing, Melbourne, Australia.
Jørgensen D. 2015. Rethinking rewilding. Geoforum 65:482–488.
Law A, Gaywood MJ, Jones KC, Ramsay P, Willby NJ. 2017. Using ecosys-
tem engineers as tools in habitat restoration and rewilding: beaver
and wetlands. Science of The Total Environment 605–606:1021-
Law A, McLean F, Willby NJ. 2016. Habitat engineering by beaver ben-
efits aquatic biodiversity and ecosystem processes in agricultural
streams. Freshwater Biology 61:486–499.
Letnic M, Ritchie EG, Dickman CR. 2012. Top predators as biodiversity
regulators: the dingo Canis lupus dingo as a case study. Biological
Lindenmayer DB, et al. 2014. New policies for old trees: averting a
global crisis in a keystone ecological structure. Conservation Letters
Martin BG. 2003. The role of small ground-foraging mammals in topsoil
health and biodiversity: implications to management and restora-
tion. Ecological Management & Restoration 4:114–119.
Marzinelli EM, Leong MR, Campbell AH, Steinberg PD, Verg´
es A. 2016.
Does restoration of a habitat-forming seaweed restore associated
faunal diversity? Restoration Ecology 24:81–90.
Medina FM, Bonnaud E, Vidal E, Tershy BR, Zavaleta ES, Josh Donlan C,
Keitt BS, Corre M, Horwath SV, Nogales M. 2011. A global review
of the impacts of invasive cats on island endangered vertebrates.
Global Change Biology 17:3503–3510.
Mills CH, Gordon CE, Letnic M. 2017. Rewilded mammal assemblages
reveal the missing ecological functions of granivores. Functional
Mills CH, Letnic M. 2018. Reversing functional extinction of mam-
mals prompts a rethink of paradigms about seed fate in arid Aus-
tralia. Royal Society Open Science 5https://doi.org/10.1098/rsos.
Monbiot G. 2013. Feral: searching for enchantment on the frontiers of
rewilding. Penguin, London, United Kingdom.
Morris T, Letnic M. 2017. Removal of an apex predator initiates a trophic
cascade that extends from herbivores to vegetation and the soil nu-
trient pool. Proceedings of the Royal Society B: Biological Sciences
Moseby KE, Blumstein DT, Letnic M. 2016. Harnessing natural selection
to tackle the problem of prey na¨
e. Evolutionary Applications
Moseby KE, Crowther MS, Letnic M. 2018. Ecological role of an
apex predator revealed by a reintroduction experiment and
Bayesian statistics. Ecosystems https://doi.org/10.1007/s10021-018-
Moseby KE, Hill BM, Read JL. 2009. Arid recovery–a comparison of
reptile and small mammal populations inside and outside a large
rabbit, cat and fox-proof exclosure in arid South Australia. Austral
over C, et al. 2017. The science, policy and practice of nature-
based solutions: an interdisciplinary perspective. Science of The
Total Environment 579:1215–1227.
es-Bravo D, Simberloff D, Rahbek C, Sanders NJ. 2016. Rewilding
is the new Pandora’s box in conservation. Current Biology 26:R87–
Pech R, Maitland M. 2016. Conservation of native fauna in highly in-
vaded systems: managing mammalian predators in New Zealand.
Restoration Ecology 24:816–820.
Pettorelli N, Barlow J, Stephens PA, Durant SM, Connor B, Schulte to
uhne H, Sandom CJ, Wentworth J, . 2018. Making rewilding fit for
policy. Journal of Applied Ecology 55:1114–1125.
Prior J, Ward KJ. 2016. Rethinking rewilding: a response to Jørgensen.
Prowse TAA, Johnson CN, Cassey P, Bradshaw CJA, Brook BW.
2014. Ecological and economic benefits to cattle rangelands of
restoring an apex predator. Journal of Applied Ecology 52:455–
Regos A, Dom´
ınguez J, Gil-Tena A, Brotons L, Ninyerola M, Pons X.
2016. Rural abandoned landscapes and bird assemblages: winners
and losers in the rewilding of a marginal mountain area (NW Spain).
Regional Environmental Change 16:199–211.
Volume 00, No. 0, 2019
Sweeney et al. 9
Renwick AR, Robinson CJ, Garnett ST, Leiper I, Possingham HP, Car-
wardine J. 2017. Mapping Indigenous land management for threat-
ened species conservation: an Australian case-study. PLOS ONE 12
Ripple WJ, Beschta RL. 2007. Restoring Yellowstone’s aspen with
wolves. Biological Conservation 138:514–519.
Ripple WJ, et al. 2015. Collapse of the world’s largest herbivores.
Science Advances 1(e1400103) https://doi.org/10.1126/sciadv.
Ritchie EG, Elmhagen B, Glen AS, Letnic M, Ludwig G, McDonald RA.
2012. Ecosystem restoration with teeth: What role for predators?
Trends in Ecology & Evolution 27:265–271.
Rohwer Y, Marris E. 2016. Renaming restoration: conceptualizing and
justifying the activity as a restoration of lost moral value rather than
a return to a previous state. Restoration Ecology 24:674–679.
Rubenstein DR, Rubenstein DI. 2016. From Pleistocene to trophic
rewilding: a wolf in sheep’s clothing. Proceedings of the Na-
tional Academy of Sciences 113 https://doi.org/10.1073/pnas.
Seddon PJ, Griffiths CJ, Soorae PS, Armstrong DP. 2014. Reversing defau-
nation: restoring species in a changing world. Science 345:406–412.
Silver MJ, Carnegie AJ. 2017. An independent review of bell miner
associated dieback. Final report New South Wales Office of
Environment and Heritage, Sydney, Australia. Available from http://
associated-dieback-independent-review.pdf (accessed July 2017).
e ME, Estes JA, Berger J, Del Rio CM. 2003. Ecological effectiveness:
conservation goals for interactive species. Conservation Biology
Stringer AP, Gaywood MJ. 2016. The impacts of beavers Castor spp.
on biodiversity and the ecological basis for their reintroduction to
Scotland, UK. Mammal Review 46:270–283.
Svenning J-C, et al. 2016. Reply to Rubenstein and Rubenstein: time to
move on from ideological debates on rewilding. Proceedings of the
National Academy of Sciences 113:E2–E3.
Thomsen MS, Wernberg T, Altieri A, Tuya F, Gulbransen D, McGlathery
KJ, Holmer M, Silliman BR. 2010. Habitat cascades: the conceptual
context and global relevance of facilitation cascades via habitat
formation and modification. Integrative and Comparative Biology
Thomson JR, et al. 2015. Avifaunal disarray: quantifying models of the
occurrence and ecological effects of a despotic bird species. Diver-
sity and Distributions 21:451–464.
Van Eeden LM, Crowther MS, Dickman CR, Macdonald DW, Rip-
ple WJ, Ritchie EG, Newsome TM. 2017. Managing conflict be-
tween large carnivores and livestock. Conservation Biology 32:26–
Wallach AD, Ripple WJ, Carroll SP. 2015. Novel trophic cascades:
apex predators enable coexistence. Trends in Ecology & Evolution
Watson DM, Watson MJ. 2015. Wildlife restoration: mainstreaming
translocations to keep common species common. Biological Con-
White LC, Saltr´
e F, Bradshaw CJA, Austin JJ. 2018. High-quality fossil
dates support a synchronous, Late Holocene extinction of devils
and thylacines in mainland Australia. Biology Letters 14 https://
Woinarski JCZ, Burbidge AA, Harrison PL. 2014. The action plan for
Australian Mammals 2012. CSIRO, Collingwood, Australia.
Woinarski JCZ, Burbidge AA, Harrison PL. 2015. Ongoing unraveling of
a continental fauna: decline and extinction of Australian mammals
since European settlement. Proceedings of the National Academy of
Volume 00, No. 0, 2019