read the article corlett 2016 and answer the questions 
Rewilding Questions 

Define ecological restoration, reintroduction, and rewilding.
Briefly describe how the goals and history of rewilding differ between Europe and North America. How might other countries/continents address rewilding?
How has the Anthropocene changed the way researchers think about restoration and rewilding?
What are the arguments for and against sustained intervention? How does this fit into the ideas of restoration and rewilding?Review
Restoration, Reintroduction,
and Rewilding in a Changing
Richard T. Corlett1,*
The increasing abandonment of marginal land creates new opportunities for
restoration, reintroduction, and rewilding, but what do these terms mean in a
rapidly and irreversibly changing world? The ‘re’ prefix means ‘back’, but it is
becoming clear that the traditional use of past ecosystems as targets and
criteria for success must be replaced by an orientation towards an uncertain
future. Current opinions in restoration and reintroduction biology range from a
defense of traditional definitions, with some modifications, to acceptance of
more radical responses, including assisted migration, taxon substitution, deextinction, and genetic modification. Rewilding attempts to minimize sustained
intervention, but this hands-off approach is also threatened by rapid environmental change.
Restoration, Reintroduction, and Rewilding
The abandonment of marginal agricultural land in response to economic development [1]
creates new opportunities for restoration, reintroduction, and rewilding, but what do these
terms actually mean in a changing world? The prefix ‘re’, meaning back or again in English, can
be attached to almost any verb and appears in many terms used for active interventions in
conservation biology. These include: reconnect, recover, recreate, reforest, rehabilitate, reinforce, reintroduce, remediate, repair, restock, restore, revegetate, and rewild. Most of these
have obvious meanings, although some, such as rewild, are newly coined whereas others, such
as restore, were imported into English with the prefix already in place. Thus ecological restoration
is returning an ecosystem back to the way it was, reintroduction is returning a species back to
where it used to live, and rewilding is returning a managed area back to the wild. These terms
came into common use during the nostalgic phase of conservation biology, when the initial,
preservationist phase was running out of pristine areas to protect and the main task facing
conservationists was seen as returning degraded ecosystems to their previous state, or as close
to this as possible [2,3].
Inherent in the use of the ‘re’ prefix, however, is the question ‘back to when?’ and this has
become increasingly difficult to answer. The idea that the environment is changing unidirectionally, rapidly, and irreversibly is not new, but it is only in the past decade that it has become widely
accepted, and its consequences widely understood, in conservation biology [4,5]. In statistical
terms, most environmental parameters of relevance to the distribution and abundance of
organisms are now clearly non-stationary [4]. Natural systems at all levels have an inherent
degree of resilience, but there are thresholds of environmental change – generally unknown in
advance – beyond which system changes can become irreversible [6]. The impacts of anthropogenic climate change are largely responsible for this shift in viewpoint, but irreversible
environmental changes also arise from other human impacts, including land-use legacies such
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
Abandonment of agricultural land provides an opportunity for creating new
ecosystems, but the traditional use of
past ecosystems as targets is likely to
be inappropriate in a time of rapid environmental change.
There is no agreement among conservationists about how to replace the historically based reference frame, with
opinions ranging from minor modification to the acceptance of increasingly
radical alternatives including moving
species outside their current native
ranges, using non-native taxon substitutions to maintain key functions, and
the acceptance of novel ecosystems
that are different from any past analogs.
New technologies will facilitate the
genetic modification of threatened
species and make the ‘de-extinction’
of at least some species possible, providing new, controversial options for
Future debates seem likely to increasingly focus on the degree of human
intervention that is desirable as ‘wildness’ is seen as an increasingly important attribute. Rewilding attempts to
minimize sustained intervention, but
this approach is also threatened by
rapid environmental change.
Center for Integrative Conservation,
Xishuangbanna Tropical Botanical
Garden, Chinese Academy of
Sciences, Menglun, Mengla, Yunnan
666303, China
(R.T. Corlett).
© 2016 Elsevier Ltd. All rights reserved.
as soil erosion, nutrient enrichment, population and species extinctions, and invasive alien
species – all markers of the proposed new geological epoch, the Anthropocene (see Glossary)
[4]. If we cannot go back, the traditional use of present and past ecosystems as targets and
criteria for success in ecological interventions must be replaced by an orientation not just
towards the future, but towards an uncertain future. Nostalgia is no longer an option, but what
should replace it?
A Taxonomy of Terms
Three clusters of related terms are widely used in the recent (2010–2015) conservation literature
(Table 1). One group fits under the umbrella of restoration in the broad sense of ‘assisting the
recovery of an ecosystem that has been degraded, damaged, or destroyed’ [7] and includes
restoration in the strict sense of restoring species composition, structure, and function to an
approximation of a historical reference system, as well as the less ambitious targets of reforestation, revegetation, rehabilitation, and reclamation and the more human-focused approach of
ecological engineering. A second group of terms fits under the IUCN’s definition of conservation
translocation, which is the movement and release of organisms for conservation reasons,
including reintroduction and reinforcement, where the organisms are released within their
indigenous range, as well as conservation introductions outside this range, to avoid extinction
(assisted colonization) or to restore ecological function (ecological replacement or taxon
substitution) [8]. Assisted migration, the most widely used term for overcoming dispersal
limitations in species that will be harmed by climate change, is best understood as a subcategory
of assisted colonization [9]. Two additional terms are not used in the IUCN guidelines: assisted
Table 1. A Taxonomy of the Major Terms Mentioned in this Review with a Brief Explanation of Their Recent
Umbrella Term
Key Element in Usage
Restoration (in a strict sense)
Restoring original composition and function
Functional restoration
Prioritizing function over species composition
Restoring forest cover
Restoring vegetation cover
Returning highly degraded sites to usefulness
Returning highly degraded sites to usefulness
Ecological engineering
Creating sustainable ecosystems with both
human and ecological value
Release within previous native range
Release into an existing population
Assisted gene flow
Release within native range to assist adaptation
Pleistocene reintroduction
Release within the Pleistocene range
Conservation introduction
Release outside the native range
To avoid extinction
Assisted migration
To keep up with climate change
Ecological replacement
To restore an ecological function
Mostly of harvested wild populations
Trophic rewilding
Introductions to restore top-down trophic interactions
Pleistocene rewilding
Restoring to a pre-human Pleistocene baseline
Ecological rewilding
Allowing natural processes to regain dominance
Passive rewilding
Little or no human interference
Assisted colonization
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
Anthropocene: a proposed
geological epoch following the
Holocene that began when human
activities started to have a major
impact on the global environment.
Various starting dates have been
suggested, with around 1800 or
1950 having the most support
De-extinction: the process of
bringing a species – or something
closely resembling it – back from
extinction. Advances in genetics and
reproductive technology make it likely
that this will be possible for some
species within the next few years.
Ex situ conservation: literally ‘offsite conservation’ that is, protecting
an endangered plant or animal
species outside its natural habitat, in
zoos, botanical gardens, seed banks,
or gene banks.
Taxon substitution: the
replacement of an extinct species by
a functionally similar substitute to
restore ecological processes. The
substitute may or may not be closely
related to the extinct species.
Virtual fences: the reliance on
techniques other than physical
barriers to modify animal behavior at
boundaries. Examples include
sensory deterrents, biological
barriers, training collars, and real-time
tracking systems.
Box 1. A Brief History of Rewilding
The term rewilding was coined 25 years ago in North America for the restoration of large, connected wilderness areas that
support large, wide-ranging animals, with an emphasis on carnivores [45]. When it was adopted in Europe, however,
large carnivores were de-emphasized, while the focus on large connected areas and other large animals remained [63].
Another transatlantic difference in current usage is that the absence of sustained human intervention is central to
European rewilding; indeed, rewilding in Europe can be entirely passive [31]. This aspect has not usually been
emphasized in North America, although a major justification for rewilding there has been that the resulting ecosystems
are expected to be self-sustaining. Much of Europe also lacks the existing wilderness areas that form the core of most
North American rewilding proposals. These differences to a large extent reflect Europe’s higher human population
density and longer history of intensive human land use. The maintenance of diverse early successional anthropogenic
habitats following the abandonment of the agricultural practices that created them has been a major focus for European
conservation [37,64].
This has also led to significant philosophical differences. While the aim in North America was initially to restore the preColumbian wilderness, with all of its large vertebrates, the major aim in Europe has been to create ‘wildness’ (autonomy,
spontaneity, self-organization, absence of human control) in areas that have been managed for millennia [65]. PreNeolithic Europe is often cited as an example of what this wildness could look like [66], but more as an inspiration than a
target, and most European projects are explicitly future oriented [31,40]. Of course, pre-Columbian North America was
also inhabited, a fact that has prompted the suggestion of an earlier historical reference state before the megafaunal
extinctions of the Late Pleistocene, to be achieved by introducing extant conspecifics and related taxa [55]. One
consequence of these differences is that objections to rewilding in North America have often focused on the perceived
risks that large carnivores pose to people and their livestock, whereas in Europe the loss of traditional biocultural
landscapes has been of greater concern [64]. However, carnivore populations have recovered dramatically in Europe
without help from deliberate rewilding and now pose a potential threat to the ‘no intervention’ paradigm [35].
geneflow involves reinforcement with conspecifics carrying genes that can help adaptation to
environmental change, whereas restocking is mostly used for boosting populations of harvested
A distinction that is not inherent in the nomenclature is that restoration has traditionally focused
on vegetation, with a largely passive approach to restoring animal populations [10], whereas
reintroduction and related activities have been dominated by animals, particularly vertebrates.
Were it not for these divergent traditions, these two clusters could probably be merged. A recent
proposal to use routine translocations of dispersal-limited animal species (termed ‘wildlife
restoration’) to keep common species common by infilling gaps in their current distributions
bridges this gap [11].
Rewilding has not yet achieved the maturity and respectability of restoration and conservation
introduction and has been used in various different ways, but it is clearly distinct in both
philosophy and methods (Box 1). It is useful to distinguish two extreme approaches: trophic
rewilding, where the aim is to restore ecosystem functions by restoring top-down trophic
interactions, and passive rewilding, where human interference is minimized from the start
[12]. An additional term, ecological rewilding, has been applied to an intermediate approach
that might be most appropriate in highly modified landscapes, such as most of Europe [13]. Both
rewilding and reintroduction can be prefaced by Pleistocene to indicate a historical baseline – or,
at least, an inspiration – in the late Pleistocene, before widespread megafaunal extinctions.
Most other ‘re’ words in common use in conservation, such as reconnect, recreate, and repair,
are usually used in their everyday senses rather than as technical terms, so they are not
considered further here. However, their frequent use reinforces the impression that conservation
is fundamentally about nostalgia: a longing for the past [3]. Reconciliation (Latin: bring back
together) has a specific meaning in reconciliation ecology, which refers to attempts to encourage
biodiversity in human-dominated landscapes – in many ways, the opposite of restoration and
rewilding [14]. Despite the ‘re’ prefix, this usage does not imply a return to a former state,
reflecting the broad use of this word in everyday English. Resilience (Latin: jump back) is another
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
‘re’ word, but is often used as a system property without reference to a historical state, so even
novel ecosystems can be resilient.
Adjusting to the Anthropocene
Historical baselines have always been contentious in conservation, with fears of ‘shifting
baselines’ when systems are compared with earlier reference states that themselves differ
significantly from the original state of the system [15]. Pleistocene rewilding in North America
was an attempt to avoid this problem by choosing a baseline before human arrival (Box 1) and
there have been similar arguments in Australia and Europe, where modern humans arrived even
earlier. What has changed in the past decade, however, has been an increasing recognition that
the accelerating and effectively irreversible environmental change of the Anthropocene puts
any historical baseline out of reach [4,6]. Climate change has received most attention, partly
because it is most easily modeled, but other changes are the focus in some cases (e.g., soil
nutrients [16]).
The widespread awareness of environmental change has not, however, led to widespread
agreement on how conservation should respond. Hobbs [17] suggests that the polarization of
responses reflects different stages of grief in response to the ongoing loss of biodiversity, from
initial denial to final acceptance, but obviously those he considers to be in the earlier stages
would not accept this diagnosis. Conceptual tensions resulting from the new perspectives are
clearest in restoration ecology, which has traditionally been defined by a historically based
reference frame [10,18]. Some have argued that this frame needs to be modified rather than
abandoned, since it is what distinguishes restoration ecology from revegetation for erosion
control or aesthetic reasons [19–21]. Suggested modifications include recognizing the contributions of past human impacts to the reference frame and aiming to construct resilient
assemblages of native species that have a better chance of adapting to future changes. Others
express a willingness to tolerate and, in some cases, manage for novel ecosystems (Box 2) with
no historical analogs [22–24]. These shifts in attitudes have coincided with, and been reinforced
by, a reorientation away from species composition as a goal and towards a focus on ecosystem
function [10,25].
Box 2. Dealing with Novel Ecosystems
Novelty defines the Anthropocene [4] and biotic novelty – extinctions and invasions – is a major challenge to restoration,
reintroduction, and rewilding since it can put traditional conservation targets beyond reach. The term novel ecosystem
has been used in various ways, but most often for ecosystems that differ from historical ecosystems as a result of human
impacts [33]. Most authors restrict it to ecosystems that will persist without human intervention, thus excluding
croplands, and some require that they have crossed an ecological threshold that makes the changes impossible to
reverse [24]. Ignoring novel ecosystems is no longer an option since, depending on the definition, they include much to all
of the land newly available for conservation. Indeed, the human role in ‘historical ecosystems’ is widely underestimated
[20]. Recognizing that we inhabit an ‘anthropogenic biosphere’ [48] does not, however, mean accepting that ‘anything
goes’, since ignoring the ecological memories in a landscape (e.g., remnant vegetation, soil properties, seed banks) is
neither practical nor desirable [18]. If restoration is defined as moving from an undesired ecosystem state to a desired
one, it is easy to broaden the concept from restoration to a desired historical reference state to achieving other goals,
including restoration of desired ecosystem functions such as water infiltration and conservation of one or more desired
species [67]. Rather than evaluating success against a fixed baseline, the results of conservation interventions would then
be compared with a counterfactual; that is, what would have occurred without the interventions [68].
Deviation from historical models has proved easier to accept on oceanic islands and in Australia, where extinctions and
invasions have had a dominant influence on present-day ecosystems. Non-native tortoises have been introduced to
control invasive plants on Round Island, Mauritius [69], while in Australia it has been suggested that introduced dingoes
should be viewed favorably for their impact on invasive cats and foxes and that elephants could be introduced to control
invasive grasses [70]. If restoration is thus freed from its traditional constraints, the difference from rewilding is only the
level of intervention, ranging from a continued high level to maintain a desired state through initial species introductions to
push an ecosystem in a desired direction [70] to embracing whatever nonintervention brings [31]. As with all conservation
interventions, however, experimental tests of optimistic forecasts are essential.
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
The traditional focus of reintroduction on the species themselves rather than their ecological
roles has made it easier to incorporate some nontraditional targets, such as assisted migration to
sites outside the native range that are projected to have a suitable climate in the future, but more
difficult for practitioners to accept proposals for substituting functionally important extinct native
species by related or functionally similar non-natives [5,8]. However, there are already ‘shades of
nativeness’ in landscapes with a long history of human impacts, even before functional substitutions for extinct species are considered [26], and non-native taxon substitutions could
potentially reduce the need for other interventions by restoring ecological processes [27]. Taxon
substitutions have many similarities with deliberate introductions for biological control – which, it
should be remembered, were the source of many highly invasive species – and could usefully
adopt the same stringent guidelines, including initial quarantine, small-scale field trials, and postrelease monitoring [27]. Similar issues will undoubtedly arise in the future as it becomes practical
to apply new molecular tools to genetically modify threatened and functionally important native
species to accelerate their adaption to changing environments [25]. De-extinction of at least
some extinct native taxa might soon be another option [28]. Although this is likely to be less
controversial than taxon substitution, concerns about unplanned impacts are reasonable when
the original extinction was back in the Pleistocene or early Holocene.
Rewilding’s origins were explicitly nostalgic, but the recent literature, particularly in Europe,
focuses on ‘future wildness’ rather than recreating the past (Box 1). Despite the range of different
approaches included under the rewilding umbrella, a common feature is a belief that natural
processes can achieve conservation objectives, including adjustment to environmental change,
better than active human management. Trophic rewilding is based on a belief in the power of
top-down ecological control through trophic cascades, although there is little direct evidence for
the generality of this mechanism with large carnivores [29]. In Europe, it has been suggested that
grazing by large herbivores might be able to maintain the open habitats that forest recovery
would otherwise threaten [12]. While there is evidence that the diverse and abundant large
herbivore guild in the last interglacial (including extinct species of elephant and rhinoceros)
achieved this, the depleted herbivore assemblage of the early Holocene, which is a better model
for what is achievable in modern Europe, apparently did not [30]. Passive rewilding is also based
on a ‘leave it to nature’ philosophy, although the justifications in this case tend to be more
philosophical than scientific [31].
To Intervene or Not to Intervene
The recent literature suggests that a major axis of variation in conservation, which is not
adequately reflected in the current terminology, is the question of if and when to intervene
[6,32]. A good illustration of this is the range of attitudes to invasive species, which vary from
elimination or control whatever the costs, as has been traditional in restoration ecology, to
tolerance and even encouragement of novel ecosystems where they are impossible or impractical to eliminate [33] (Box 2). Restoration was traditionally the active side of conservation, but
conservation as a whole is now becoming more interventionist [34]. All interventions have
associated risks, however, and can have unintended consequences. Future management will
often need to be anticipatory, with actions aimed at how the system is expected to be in the
future. Moreover, conservation actions on larger spatial scales cannot practicably be scaled up
from local actions [34].
Rewilding’s emphasis on little or no sustained management – with or without initial introductions
of keystone species – contrasts strongly with the increased level of intervention implicit in many
visions for the future of conservation biology. However, while some rewilding advocates favor
simply letting ecosystems evolve out of human control [31], there is an ongoing debate in
conservation on the need for sustained intervention to minimize human–wildlife conflicts [35], to
control invasive species that can transform ecosystems [25], to restore ‘natural’ disturbance
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
regimes [36], to maintain open habitats for species that are threatened by the encroachment of
forest [36,37], to overcome dispersal limitation in plants and animals [38], and to adapt to rapid
climate change [39].
In densely populated regions, compromises are unavoidable [40]. These compromises will most
often involve active interventions in specific areas to maintain particular species and their
habitats, while other areas are left alone. Fencing between unmanaged areas and intensively
managed, human-dominated landscapes is an option [41], particularly for experimental purposes, but fences are unselective and intrusive and ‘virtual fences’ of various forms are a littleexplored alternative [42]. Some problems, however, might require intervention across the entire
landscape. Plant invasions are already a massive problem on oceanic islands and now a growing
one in continental protected areas [43]. Highly invasive pests and diseases, such as chytridiomycosis in amphibians and chestnut blight in the American chestnut, also provide a major
challenge to a ‘hands-off’ approach on any scale, since it might be impossible to maintain
ecological functions and prevent extinctions without sustained, intensive intervention [21,25,44].
Climate change in areas with a high projected climate change velocity is another problem that will
require more than local intervention [39].
The need for interventions to maintain biodiversity and ecosystem functions, and the aggressiveness of these interventions, will be greater the faster the rate of environmental change
(Figure 1). The need is also likely to be much greater in smaller, more isolated areas than in the
very large, connected ecosystems envisaged by the originators of the rewilding concept [45], but
rapid environmental change can overwhelm the capacity of even the best-connected ecosystems to adapt [39]. Where rapid changes lead to phenotype–environment mismatches, as is
likely to occur in many long-lived, poorly dispersed species, possible management interventions
include modifying the local environment (for example, by reducing soil nutrient levels [16]),
assisted migration to areas with a more suitable environment [9], or genetic modification to
improve the fit to the new environment [25,46]. The last of these options has not been practical in
the past but seems likely to become so in the near future, judging by recent progress in
agriculture [47].
The enhanced dichotomy between nature and human culture implied by rewilding has not
always been welcomed, particularly in Europe, where nature and culture have interacted for
millennia [37]. At the opposite end of the intervention spectrum from that occupied by large-scale
rewilding are attempts to maximize biodiversity in multifunctional landscapes that include
agriculture and human settlements [14,48]. Success in this endeavor to reconcile people
and nature will depend on both land sparing, where urbanization and agricultural intensification
free land for wild species, and land sharing, where wild species live within the urban and
agricultural matrix. Many sensitive wild species do poorly in such landscapes [48,49], but those
that thrive contribute more to human experiences of nature – and some components of human
Restora on and
reintroduc on
with historical
reference state
Rate of environmental change
Na ve species
and genotypes
adapted to
future condi ons
Assisted migra on
of species
beyond their
na ve ranges
Non-na ves
and gene c
modifica on
of na ves
Figure 1. Possible Conservation Interventions in Relation to the Rate of Environmental Change. Traditional
restoration and reintroduction assume little or no environmental change since the historical baseline. Careful selection of
native species and genotypes can increase resilience to greater rates of change, but if the rate exceeds the capacity of the
local biota to adjust, intervention in the form of assisted migration of species beyond their native ranges might be necessary.
At the highest rates of change, it might be necessary to use non-native species or to genetically modify native species.
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
well-being [50] – than those in remote and more extensive wild areas. Although the philosophies
of rewilding and reconciliation ecology are opposites, there is no ecological reason why large,
low-intervention rewilded areas and biodiversity-rich multifunctional landscapes cannot coexist
at regional and continental scales.
The Way Forward
Many of the questions raised by rapid environmental change do not have purely scientific
answers. In particular, the move away from historical reference systems, the rewilding of ancient
cultural landscapes, the use of taxon substitutions, and the potential use of genetic modification
raise important ethical issues that cannot be ignored [10]. Modern conservation has always had
an ethical basis, but as the issues becomes greyer and less tidy in the Anthropocene the
underlying imperative to preserve and protect nature will not always lead to a single, simple,
optimal solution. Looking forward is necessarily more difficult than looking backwards, although
history also has biases and uncertainties that increase the further back in time you go [3]. If
historical continuity is completely abandoned as a goal, conservation risks becoming merely a
form of landscaping, driven by aesthetic and engineering considerations [18]. Even the most
forward-looking of conservationists agree that interventions – and nonintervention – need to be
historically informed, with historical knowledge used as a guide, not a template [18,24,33]. The
past – or, ideally, a range of pasts – reflects the environmental conditions to which the regional
species pool is adapted and shows the local species assemblages that are possible with this
biota (Figure 2). Moreover, the most plausible futures in most places are likely to be only
incrementally different from today, so a complete break with the past is unnecessary [51].
c. 120 000 BP
c. 6000 BP
100–500 BP
Diverse, abundant
megafauna, more
open habitats
Extensive closed
forest, restricted
open habitats
Less forest cover,
low intensity
Expanding forest
cover, restricted
open habitats
Ac on
Introduce taxon
subs tutes for
ex nct taxa
extant large
tradi onal land
Historical and ecological con nuity
Figure 2. Possible Conservation Baselines in Europe and Related Conservation Interventions. The last
interglacial represents the potential landscape under a modern climate but without modern humans [30], the early Holocene
represents a human-occupied Europe before agriculture, the historical period represents a human-dominated landscape
before industrialization, and the future is the remainder of this century. The dates are years before present (BP). Images of a
straight-tusked elephant, Eurasian wolf, and domesticated sheep are from Wikimedia Commons, reproduced under a
Creative Commons License.
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
It is not possible to separate consideration of timescales from those of space. Conservation has
traditionally thought big, but intervention-intensive restoration projects are limited to small areas
by practical considerations, and often contracts. Unless care is taken, this can result in isolated
patches that are vulnerable to all of the problems that affect fragments of natural ecosystems
[52]. To avoid these problems, local projects must be seen as embedded in landscape, regional,
and global settings [53]. Where conservation action is needed on regional scales, rewilding, with
or without vertebrate introductions, is probably the only practical option at present. A global
perspective is particularly necessary for long-distance migrants whose survival depends on
conditions at multiple sites [54].
A focus on ecological functions and processes can make it much easier to project historical
models into an uncertain future [10,51], but this approach also has its risks. The use of traitbased models to achieve functionally defined targets has been proposed [51] but requires that
the measured traits are adequate proxies for ecological functions. Moreover, the range of
functions and processes displayed in recent landscapes in much of the world is only a subset
of those seen before the megafaunal extinctions of the past 50 000 years [30,55] (Figure 2). Also,
whereas most functions and processes in natural systems are dominated by common species,
and could thus be replicated in much simpler systems, less common species can possess
unusual combinations of functional traits that provide a degree of insurance against environmental changes in the longer term [56]. Moreover, biodiversity has other values – aesthetic,
cultural, and ethical – that are independent of its ecological functions.
Finally, it is important to note that the Anthropocene has not been the only driver of changes in
conservation practice over the past decade. There has also been an increasing recognition of the
need for greater efficiency and cost-effectiveness in response to the scale of the problems to be
tackled [10,21,57], a greater awareness of the importance of social and cultural factors in
conservation [10], and calls for greater public involvement in conservation activities [10,11].
Opposed to these drivers of change are institutional inertia, social resistance, and lack of
experience in the necessary technologies [58], as well as the continued uncertainties in the
projections of environmental change. It is also clear that conservation practitioners on the ground
tend to be more conservative than the writers of academic articles [59].
Concluding Remarks
A continuing worldwide decline in fertility rates, coupled with economic growth and increasing
urbanization, suggests that land abandonment will increase globally over the coming decades
as agricultural activity becomes concentrated on the most productive land. Some of this land
will have been relatively lightly impacted but much of it will be like recently abandoned land in
Europe, with altered soils, a depleted native biota, well-entrenched aliens, and poor connectivity. Along with climate change, these impacts have put many traditional conservation
targets out of reach and demand a comprehensive rethink of conservation aims and strategies. In response, there has been an explosion of radical new ideas in conservation over the
past few years and this is likely to continue. Many of the recently proposed interventions have
been – and often still are – controversial and there is a danger that policy makers will pick
actions from the expanding menu on grounds of cost, convenience, perceived ‘coolness’, or
political acceptability, whereas the risks of unforeseen consequences are overlooked. The
uncertainties need first to be reduced by further research (see Outstanding Questions),
including large-scale trials in fenced enclosures. However, the most important conservation
debates in the coming decades will probably not be about baselines, targets, and techniques,
but about if and when to intervene, and we need agreed criteria to facilitate these decisions.
Meanwhile, it may be useful to develop a new vocabulary for the developing forward-looking
conservation paradigms, rather than trying to stretch the meanings of terms that are inherently
backward looking.
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
Outstanding Questions
What happens if large areas of former
agricultural land are simply left alone
(i.e., passively rewilded)? Are the
results desirable from a biodiversity
and ecosystem services perspective
and are they acceptable to local and
regional stakeholders?
When is human intervention necessary
to prevent species extinctions in natural
areas? Is intervention necessary in
response to rapid climate change
and species invasions even in large,
connected areas?
How can the restoration techniques
used in small patches be scaled up
to landscapes and regions? Conversely, can rewilding be scaled down?
Is wildness a reasonable and attainable
goal? How can we measure it? Is maximizing wildness compatible with the
traditional goals of protecting biodiversity and maintaining ecosystem services in a rapidly changing world?
How can the new molecular technologies contribute to conservation goals?
When should we genetically modify wild
species, if ever? Is de-extinction useful?
The author has tested the patience of many colleagues while working on this review, but is particularly grateful to Alice
Hughes and David Dudgeon for useful inputs and to Zhou Meiling, whose Masters project sparked his interest in these
issues. Two reviewers made a big difference to the final version. The author was funded by the 1000 Talents Program
1. Queiroz, C. et al. (2014) Farmland abandonment: threat or opportunity for biodiversity conservation? A global review. Front. Ecol.
Environ. 12, 288–296
26. Crees, J.J. and Turvey, S.T. (2015) What constitutes a ‘native’
species? Insights from the Quaternary faunal record. Biol. Conserv. 186, 143–148
2. Wilson, E.O. (1992) The Diversity of Life, Norton
27. Aslan, C.E. et al. (2014) Building taxon substitution guidelines on a
biological control foundation. Restor. Ecol. 22, 437–441
3. Alagona, P.S. et al. (2012) Past imperfect: using historical ecology
and baseline data for contemporary conservation and restoration
projects. Environ. Philos. 9, 49–70
4. Corlett, R.T. (2015) The Anthropocene concept in ecology and
conservation. Trends Ecol. Evol. 30, 36–41
5. Seddon, P.J. et al. (2014) Reversing defaunation: restoring species in a changing world. Science 345, 406–412
6. Wiens, J.A. and Hobbs, R.J. (2015) Integrating conservation and
restoration in a changing world. Bioscience 65, 302–312
7. Society for Ecological Restoration (2004) The SER International
Primer on Ecological Restoration, Society for Ecological Restoration
8. IUCN/SSC (2013) Guidelines for Reintroductions and Other Conservation Translocations. Version 1.0, IUCN Species Survival
9. Hällfors, M.H. et al. (2014) Coming to terms with the concept of
moving species threatened by climate change – a systematic
review of the terminology and definitions. PLoS ONE 9, e102979
10. Perring, M.P. et al. (2015) Advances in restoration ecology: rising
to the challenges of the coming decades. Ecosphere 6, art131
11. Watson, D.M. and Watson, M.J. (2015) Wildlife restoration: mainstreaming translocations to keep common species common. Biol.
Conserv. 191, 830–838
12. Svenning, J-C. et al. (2015) Science for a wilder Anthropocene:
synthesis and future directions for trophic rewilding research.
Proc. Natl. Acad. Sci. U.S.A. 113, 898–906
13. Pereira, H.M. and Navarro, L.M. (2015) Preface. In Rewilding
European Landscapes (Navarro, L.M. and Pereira, H.M., eds),
pp. v–x, Springer
14. Martin, L.J. et al. (2014) Conservation opportunities across the
world’s anthromes. Divers. Distrib. 20, 745–755
15. Corlett, R.T. (2013) The shifted baseline: prehistoric defaunation in
the tropics and its consequences for biodiversity conservation.
Biol. Conserv. 163, 13–21
16. Schelfhout, S. et al. (2015) Phosphorus mining for ecological
restoration on former agricultural land. Restor. Ecol. 23, 842–851
17. Hobbs, R.J. (2013) Grieving for the past and hoping for the future:
balancing polarizing perspectives in conservation and restoration.
Restor. Ecol. 21, 145–148
18. Higgs, E. et al. (2014) The changing role of history in restoration
ecology. Front. Ecol. Environ. 12, 499–506
19. Aronson, J. et al. (2014) The road to confusion is paved with novel
ecosystem labels: a reply to Hobbs et al. Trends Ecol. Evol. 29,
20. Balaguer, L. et al. (2014) The historical reference in restoration
ecology: re-defining a cornerstone concept. Biol. Conserv. 176,
21. Jacobs, D.F. et al. (2015) Restoring forests: what constitutes
success in the twenty-first century? New Forests 46, 601–614
22. Davis, M.A. et al. (2011) Don’t judge species on their origins.
Nature 474, 153–154
23. Fischer, L.K. et al. (2013) Creating novel urban grasslands by
reintroducing native species in wasteland vegetation. Biol. Conserv. 159, 119–126
24. Hobbs, R.J. et al., eds (2013) Novel Ecosystems: Intervening in the
New Ecological World Order, Wiley-Blackwell
25. Dumroese, R.K. et al. (2015) Considerations for restoring temperate forests of tomorrow: forest restoration, assisted migration, and
bioengineering. New Forests 46, 947–964
28. Seddon, P.J. et al. (2014) Reintroducing resurrected species: selecting de-extinction candidates. Trends Ecol. Evol. 29, 140–147
29. Ford, A.T. and Goheen, J.R. (2015) Trophic cascades by large
carnivores: a case for strong inference and mechanism. Trends
Ecol. Evol. 30, 725–735
30. Sandom, C.J. et al. (2014) High herbivore density associated with
vegetation diversity in interglacial ecosystems. Proc. Natl. Acad.
Sci. U.S.A. 111, 4162–4167
31. Schnitzler, A. (2014) Towards a new European wilderness:
embracing unmanaged forest growth and the decolonisation of
nature. Landsc. Urban Plan. 126, 74–80
32. Götmark, F. (2013) Habitat management alternatives for conservation forests in the temperate zone: review, synthesis, and implications. For. Ecol. Manag. 306, 292–307
33. Truitt, A.M. et al. (2015) What is novel about novel ecosystems:
managing change in an ever-changing world. Environ. Manag. 55,
34. Hobbs, R.J. et al. (2011) Intervention ecology: applying ecological
science in the twenty-first century. Bioscience 61, 442–450
35. Boitani, L. and Linnell, J.D.C. (2015) Bringing large mammals
back: large carnivores in Europe. In Rewilding European Landscapes (Pereira, H.M. and Navarro, L.M., eds), pp. 67–83,
36. Navarro, L.M. et al. (2015) Maintaining disturbance-dependent
habitats. In Rewilding European Landscapes (Pereira, H.M. and
Navarro, L.M., eds), pp. 143–167, Springer
37. Zakkak, S. et al. (2015) Assessing the effects of agricultural land
abandonment on bird communities in southern-eastern Europe. J.
Environ. Manag. 164, 171–179
38. Rey Benayas, J.M. and Bullock, J.M. (2015) Vegetation restoration
and other actions to enhance wildlife in European agricultural
landscapes. In Rewilding European Landscapes (Pereira, H.M.
and Navarro, L.M., eds), pp. 127–142, Springer
39. Corlett, R.T. and Westcott, D.A. (2013) Will plant movements keep
up with climate change? Trends Ecol. Evol. 28, 482–488
40. Sandom, C. et al. (2013) Rewilding. In Key Topics in Conservation
Biology 2 (Macdonald, D.W. and Willis, K.J., eds), pp. 430–448,
John Wiley & Sons
41. Lorimer, J. and Driessen, C. (2014) Wild experiments at the
Oostvaardersplass: rethinking environmentalism in the Anthropocene. Trans. Inst. Br. Geogr. 39, 169–181
42. Jachowski, D.S. et al. (2014) Good virtual fences make good neighbors: opportunities for conservation. Anim. Conserv. 17, 187–196
43. Foxcroft, L.C. et al. (2013) Invasive alien plants in protected areas:
threats, opportunities, and the way forward. In Plant Invasions in
Protected Areas: Patterns, Problems and Challenges (Foxcroft, L.
C. et al., eds), pp. 621–639, Springer
44. Bosch, J. et al. (2015) Successful elimination of a lethal wildlife
infectious disease in nature. Biol. Lett. 11, 20150874
45. Soulé, M.E. and Noss, R. (1998) Rewilding and biodiversity. Wild
Earth 8, 2–11
46. Carroll, S.P. et al. (2014) Applying evolutionary biology to address
global challenges. Science 346, 1245993
47. Lombardo, L. et al. (2015) New technologies for insect-resistant
and herbicide-tolerant plants. Trends Biotechnol. 34, 49–57
48. Ellis, E.C. (2015) Ecology in an anthropogenic biosphere. Ecol.
Monogr. 85, 287–331
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
49. Edwards, D.P. et al. (2015) Land-sparing agriculture best protects
avian phylogenetic diversity. Curr. Biol. 25, 1–8
50. Hartig, T. et al. (2014) Nature and health. Annu. Rev. Public Health
35, 207–228
51. Laughlin, D.C. (2014) Applying trait-based models to achieve
functional targets for theory-driven ecological restoration. Ecol.
Lett. 17, 771–784
52. Haddad, N. et al. (2015) Habitat fragmentation and its lasting
impact on Earth’s ecosystems. Sci. Adv. 1, e1500052
53. Hobbs, R.J. et al. (2014) Managing the whole landscape: historical,
hybrid, and novel ecosystems. Front. Ecol. Environ. 12, 557–564
54. Finch, T. et al. (2015) A pan-European, multipopulation assessment of migratory connectivity in a near-threatened migrant bird.
Divers. Distrib. 21, 1051–1062
55. Donlan, C.J. et al. (2006) Pleistocene rewilding: an optimistic
agenda for twenty-first century conservation. Am. Nat. 168,
56. Mouillot, D. et al. (2013) Rare species support vulnerable functions
in high-diversity ecosystems. PLoS Biol. 11, e1001569
57. Kimball, S. et al. (2015) Cost-effective ecological restoration.
Restor. Ecol. 23, 800–810
58. Stanturf, J.A. (2015) Future landscapes: opportunities and challenges. New Forests 46, 615–644
59. Kuebbing, S.E. and Simberloff, D. (2015) Missing the bandwagon:
nonnative species impacts still concern managers. Neobiota 25,
60. Mitsch, W.J. (2012) What is ecological engineering? Ecol. Eng. 45,
Trends in Ecology & Evolution, June 2016, Vol. 31, No. 6
61. Aitken, S.N. and Whitlock, M.C. (2013) Assisted gene flow to
facilitate local adaptation to climate change. Annu. Rev. Ecol. Evol.
Syst. 44, 367–388
62. Piorno, V. et al. (2015) Low persistence in nature of captive reared
rabbits after restocking operations. Eur. J. Wildl. Res. 61, 591–599
63. Höchtl, F. et al. (2005) Wilderness: what it means when it becomes
a reality – a case study from the southwestern Alps. Landsc. Urban
Plan. 70, 85–95
64. Linnell, J.D.C. et al. (2015) Framing the relationship between
people and nature in the context of European conservation. Conserv. Biol. 29, 978–985
65. Hall, M. (2014) Extracting culture or injecting nature? Rewilding in
transatlantic perspective. In Old World and New World Perspectives in Environmental Philosophy (Drenthen, M. and Keulartz, J.,
eds), pp. 17–35, Springer
66. Smit, C. et al. (2015) Rewilding with large herbivores: the importance of grazing refuges for sapling establishment and woodpasture formation. Biol. Conserv. 182, 134–142
67. Perring, M.P. et al. (2013) Incorporating novelty and novel ecosystems into restoration planning and practice in the 21st century.
Ecol. Process. 2, 18
68. Bull, J.W. et al. (2014) Importance of baseline specification in
evaluating conservation interventions and achieving no net loss
of biodiversity. Conserv. Biol. 28, 799–809
69. Griffiths, C.J. et al. (2013) Assessing the potential to restore
historic grazing ecosystems with tortoise ecological replacements.
Conserv. Biol. 27, 690–700
70. Bowman, B. (2012) Bring elephants to Australia? Nature 482, 30

Purchase answer to see full

Why Choose Us

  • 100% non-plagiarized Papers
  • 24/7 /365 Service Available
  • Affordable Prices
  • Any Paper, Urgency, and Subject
  • Will complete your papers in 6 hours
  • On-time Delivery
  • Money-back and Privacy guarantees
  • Unlimited Amendments upon request
  • Satisfaction guarantee

How it Works

  • Click on the “Place Order” tab at the top menu or “Order Now” icon at the bottom and a new page will appear with an order form to be filled.
  • Fill in your paper’s requirements in the "PAPER DETAILS" section.
  • Fill in your paper’s academic level, deadline, and the required number of pages from the drop-down menus.
  • Click “CREATE ACCOUNT & SIGN IN” to enter your registration details and get an account with us for record-keeping and then, click on “PROCEED TO CHECKOUT” at the bottom of the page.
  • From there, the payment sections will show, follow the guided payment process and your order will be available for our writing team to work on it.