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Using assisted colonisation to conserve biodiversity and restore ecosystem function under climate change

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Assisted colonisation has received considerable attention recently, and the risks and benefits of introducing taxa to sites beyond their historical range have been vigorously debated. The debate has primarily focused on using assisted colonization to enhance the persistence of taxa that would otherwise be stranded in unsuitable habitat as a consequence of anthropogenic climate change and habitat fragmentation. However, a complementary motivation for assisted colonisation could be to relocate taxa to restore declining ecosystem processes that support biodiversity in recipient sites. We compare the benefits and risks of species introductions motivated by either goal, which we respectively term ‘push’ versus ‘pull’ strategies for introductions to preserve single species or for restoration of ecological processes. We highlight that, by focusing on push and neglecting pull options, ecologists have greatly under-estimated potential benefits and risks that may result from assisted colonisation. Assisted colonisation may receive higher priority in climate change adaptation strategies if relocated taxa perform valuable ecological functions (pull) rather than have little collateral benefit (push). Potential roles include enhancing resistance to invasion by undesired species, supporting co-dependent species, performing keystone functions, providing temporally critical resources, replacing taxa of low ecological redundancy, and avoiding time lags in the provisioning of desired functions.
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Using assisted colonisation to conserve biodiversity and restore ecosystem
function under climate change
Ian D. Lunt
a
, Margaret Byrne
b,
, Jessica J. Hellmann
c
, Nicola J. Mitchell
d
, Stephen T. Garnett
e
,
Matt W. Hayward
f
, Tara G. Martin
g
, Eve McDonald-Maddden
g,h
, Stephen E. Williams
i
, Kerstin K. Zander
e
a
Institute for Land, Water & Society, Charles Sturt University, Albury, NSW, Australia
b
Department of Environment and Conservation, Bentley, WA, Australia
c
Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
d
Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, WA, Australia
e
Research Institute for The Environment and Livelihoods, Charles Darwin University, Casuarina, NT, Australia
f
Australian Wildlife Conservancy, Nichols Point, Victoria, Australia
g
Climate Adaptation Flagship, CSIRO Ecosystem Sciences, Dutton Park, Qld, Australia
h
ARC Centre for Excellence in Environmental Decisions, University of Queensland, St. Lucia, Qld, Australia
i
Centre for Tropical Biodiversity and Climate Change, James Cook University, Townsville, Qld, Australia
article info
Article history:
Received 15 April 2012
Received in revised form 6 August 2012
Accepted 24 August 2012
Keywords:
Ecological replacement
Managed relocation
Climate change adaptation
Ecosystem management
Restoration
Translocation
abstract
Assisted colonisation has received considerable attention recently, and the risks and benefits of introduc-
ing taxa to sites beyond their historical range have been vigorously debated. The debate has primarily
focused on using assisted colonization to enhance the persistence of taxa that would otherwise be
stranded in unsuitable habitat as a consequence of anthropogenic climate change and habitat fragmen-
tation. However, a complementary motivation for assisted colonisation could be to relocate taxa to
restore declining ecosystem processes that support biodiversity in recipient sites. We compare the ben-
efits and risks of species introductions motivated by either goal, which we respectively term ‘push’ versus
‘pull’ strategies for introductions to preserve single species or for restoration of ecological processes. We
highlight that, by focusing on push and neglecting pull options, ecologists have greatly under-estimated
potential benefits and risks that may result from assisted colonisation. Assisted colonisation may receive
higher priority in climate change adaptation strategies if relocated taxa perform valuable ecological func-
tions (pull) rather than have little collateral benefit (push). Potential roles include enhancing resistance to
invasion by undesired species, supporting co-dependent species, performing keystone functions, provid-
ing temporally critical resources, replacing taxa of low ecological redundancy, and avoiding time lags in
the provisioning of desired functions.
Crown Copyright Ó2012 Published by Elsevier Ltd. All rights reserved.
Contents
1. Introduction ......................................................................................................... 172
2. Push versus pull assisted colonisation . . . . . . . . . . . . . . ...................................................................... 173
3. Contrasting risk–benefit profiles ......................................................................................... 173
4. Conclusions. ......................................................................................................... 176
Acknowledgements . . . . . . . . . . ......................................................................................... 176
References . ......................................................................................................... 176
1. Introduction
Assisted colonisation (also known as assisted migration or man-
aged relocation) is one option that has been proposed to conserve
biodiversity under anticipated climate change (McLachlan et al.,
0006-3207/$ - see front matter Crown Copyright Ó2012 Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.biocon.2012.08.034
Corresponding author. Address: Science Division, Department of Environment
and Conservation, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.
Tel.: +61 8 9219 9078; fax: +61 8 9334 0327.
E-mail address: margaret.byrne@dec.wa.gov.au (M. Byrne).
Biological Conservation 157 (2013) 172–177
Contents lists available at SciVerse ScienceDirect
Biological Conservation
journal homepage: www.elsevier.com/locate/biocon
2007; Hoegh-Guldberg et al., 2008; Richardson et al., 2009). As-
sisted colonisation involves the planned introduction of a popula-
tion or species beyond its current distribution where the climate is
expected to become unsuitable into new localities where the taxon
is expected to persist under future climatic conditions (Seddon,
2010). Management under climate change will require steps after
colonisation (sensu managed relocation, Richardson et al., 2009),
but introduction is the first step in helping species relocate as
the climate changes.
The concept of assisted colonisation has generated intense de-
bate over the relative benefits and risks of moving taxa beyond
their historical range (Hoegh-Guldberg et al., 2008; Mueller and
Hellmann, 2008; Ricciardi and Simberloff, 2009; Richardson et
al., 2009; Vitt et al., 2009, 2010; Hewitt et al., 2011). The potential
benefit is the retention of biodiversity that is threatened by climate
change, but introduced populations could cause unanticipated
ecological or economic damage (Mueller and Hellmann, 2008;
Ricciardi and Simberloff, 2009; Sandler, 2010). To date, the assisted
colonisation literature has focused primarily on a single rationale:
to enhance the survival prospects of the taxon being moved, or
small numbers of inter-dependent taxa, such as butterflies and
host plants (Hellmann, 2002). However, here we suggest that as-
sisted colonisation could also be undertaken to achieve a very dif-
ferent conservation goal – to maintain declining ecosystem
processes. Adopting the terminology of Seddon (2010), this type
of assisted colonisation would be classified as ecological replace-
ment – the release of ‘a species outside its historic range in order
to fill an ecological niche left vacant by the extirpation of a native
species’, and is akin to the ‘anticipatory restoration’ activities pro-
posed by Manning et al. (2009). This goal may become prominent
in future climate change adaptation programs as the impacts of cli-
mate change become more severe, but the juxtaposition of goals
has not been considered in the assisted colonisation literature
and demands benefit–risk evaluation.
In addition to direct physiological effects on organisms and
associated changes to fitness, climate change will affect many spe-
cies through indirect impacts on ecosystem structure, functions
and processes (Diaz and Cabido, 1997; Petchey et al., 1999; Dale
et al., 2001; Gilman et al., 2010). Changes in the abundance of dom-
inant, foundation and keystone species will alter ecosystem pro-
cesses that will, in turn, affect many associated organisms.
Declines in dominant forest trees, for example, lead to changes in
micro-climatic conditions, nutrient and water cycles, habitat struc-
ture, and disturbances such as fire regimes (Cochrane, 2003; Foley
et al., 2007; Van Mantgem et al., 2009).
Reviews of climate change adaptation strategies include a wide
range of approaches for maintaining ecological processes such as
nutrient cycling, hydrology, species interactions, habitat provision,
dispersal and disturbances (Millar et al., 2007; Bennett et al., 2009;
Mawdsley et al., 2009; Steffen et al., 2009; Lindenmayer et al.,
2010). Additionally, landscape and restoration ecologists have pro-
posed that vegetation be established and restored across local and
regional scales to enhance ecological processes and functions that
may in turn maintain biodiversity (Hobbs and Harris, 2001; Millar
et al., 2007; Manning et al., 2009; Seddon, 2010). Proposals to use
assisted colonisation for ecosystem benefit are not widely encom-
passed by the existing literature and its decision frameworks
(Sandler, 2010). We suggest that acknowledgement of a broader
array of motivations for assisted colonisation will enhance our
ability to contribute to the development of national and regional
climate change adaptation strategies.
Therefore, we contrast two rationales for introductions of species
outside their historical ranges: (1) direct conservation of one or
more species diminished in their native range and (2) restoration
or maintenance of a declining ecosystem function, and consider
how these rationales could be combined. We restrict our attention
to introductions for conservation purposes, but our framework
could also encompass a wider range of goals, including utilitarian
services such as timber production (McKenney et al., 2009).
2. Push versus pull assisted colonisation
For simplicity, we characterize these two contrasting rationales
for assisted colonisation as ‘push’ and ‘pull’ strategies (Fig. 1). Push
strategies that focus on conserving individual taxa or small groups
of inter-dependent taxa are already widely discussed in the as-
sisted colonisation literature. In these cases, issues such as rarity
and threat guide the selection of target taxa, and populations are
‘pushed’ into one or more localities where it is expected that they
will maintain viable populations for an extended period under cli-
mate change (e.g. Willis et al., 2009). Risk assessments are required
to ensure that informed decisions are made to relocate taxa such
that there is minimal impact on other species where they are intro-
duced (Burbidge et al., 2011).
In contrast, assisted colonisation that is also motivated by a de-
sire to restore ecosystem function should expect to have an appre-
ciable impact at the recipient site. In such ‘pull’ scenarios, desired
ecosystem functions and potential recipient sites would first be
identified, and appropriate candidate species would then be
‘pulled’ into recipient sites to maintain or restore the specified
function (Fig. 1). Relocation of taxa may be undertaken to deliver
ecological functions that are directly affected by climate change,
or where climate change exacerbates other causes of decline, such
as fragmentation or salinisation. For example, consider a tree spe-
cies that is declining (directly or indirectly) due to climate change
and provides nest holes to a bird community. Pull assisted coloni-
sation would ask which species of tree might persist regionally in
the future to provide nesting habitat for birds, and could include
the option to introduce multiple species, if a range of species are
capable of performing the desired function. Indeed, bet-hedging
approaches that relocate multiple taxa and genotypes may be pru-
dent given uncertainties about future species performances under
climate change (Beale et al., 2008). Relocation of multiple taxa will
also be important for co-dependent species, such as insects and
their host plants or species and their parasites.
In push + pull assisted colonisation, selection of species would
be guided by the function to be performed in the recipient site,
as well as the conservation status of the relocated species. Oppor-
tunities for push + pull assisted colonisation may be limited where
rare taxa have restricted distributions due to biological constraints
because they are unlikely to have the capacity to influence ecosys-
tem processes strongly in recipient sites. However, there may be
greater opportunities to maximize conservation outcomes using
‘push + pull’ assisted colonisation in landscapes where historical
stochasticity has been a major driver of rarity (Yates et al., 2007).
While further research is required to develop decision support
tools to guide pull assisted colonisation strategies, this approach
may receive high priority where relocated taxa: (1) perform ‘key-
stone’ functions that generate a cascade of ecological services
(e.g. ecosystem engineers); (2) provide ecosystem services that
are unique or have low levels of ecological redundancy; (3) provide
functions that take long periods to become effective, e.g. hollow-
bearing trees; (4) enhance resistance to invasion by undesired
species; (5) fill temporal resource gaps driven by climate-driven
phenological shifts; and (6) maintain valued species that are highly
dependent on other species. Descriptions and examples of these
functions are provided in Table 1.
3. Contrasting risk–benefit profiles
Assisted colonisation for goals of conservation introduction
or ecological replacement both share a common mechanism of
I.D. Lunt et al. / Biological Conservation 157 (2013) 172–177 173
relocating taxa (or genotypes) beyond their historical range in or-
der to conserve biodiversity under climate change. Nevertheless,
we recognise that the two approaches have very different risk
and benefit profiles.
Assisted colonisation for species conservation benefits the relo-
cated taxon only, and minimal (if any) collateral benefits are envis-
aged for other taxa or processes in recipient sites. Indeed, the
current assisted colonisation literature emphasizes the need to
avoid relocations that may alter the composition, structure or func-
tion of recipient sites in a major way (Mueller and Hellmann, 2008;
Ricciardi and Simberloff, 2009). Nevertheless, push assisted coloni-
sation may present risks to recipient sites and ecosystems (and
potentially to the broader environment and economy) if relocated
taxa have negative impacts on other species and those impacts
spread to additional locations (Ricciardi and Simberloff, 2009;
Richardson et al., 2009). Thus, the risk–benefit profile for push as-
sisted colonisation is one of localized benefit and potentially wide
risks (akin to private benefits versus public risks in human enter-
prises), depending on the taxa under consideration (Hoegh-Guld-
berg et al., 2008; Ricciardi and Simberloff, 2009; Richardson et
al., 2009; Burbidge et al., 2011).
By focusing on the conservation of threatened species as
motivation for assisted colonization, ecologists may greatly un-
der-estimate potential benefits that may arise from such intro-
ductions in providing ecosystem services. In contrast to push
assisted colonisation, taxa also introduced as ecological replace-
ments for a degraded component of an ecosystem could have
multiple beneficiaries – including all taxa that benefit from the
environmental functions or processes that relocated species
provide. Thus, the potential biodiversity benefits provided by
push + pull assisted colonisation are far greater if their impact
flows broadly across an ecosystem. Because maintenance of eco-
system processes is a key component of climate change adapta-
tion strategies (Millar et al., 2007; Mawdsley et al., 2009; Steffen
et al., 2009; Lindenmayer et al., 2010), assisted colonisations that
maintain ecosystem function may be prioritized above those that
conserve threatened species, if relocation costs are similar, ben-
efits are greater and risks deemed acceptable. Combined strate-
gies that focus on threatened species conservation and
maintenance of ecosystem function may also rate highly under
constrained management budgets, given potential benefits to
both the relocated species and recipient ecosystems.
However, assisted colonisation intended to have a significant
collateral impact also presents far greater risks, since relocated
taxa are intended to have a substantial, as opposed to negligible,
impact on specified ecosystem processes in recipient sites. For
example, a relocated species could be structurally dominant or a
keystone species, which would be unlikely to be relocated under
current decision support frameworks for assisted colonisation
(Hoegh-Guldberg et al., 2008; Richardson et al., 2009). Candidate
taxa for assisted colonisation could now include taxa with high im-
pact but low dispersal capacity, to minimize the potential for relo-
cated taxa to spread to unwanted areas. In some cases, dispersal
risks may be moderated by landscape context (McIntyre, 2011).
For example, assisted colonisations designed to have an apprecia-
ble collateral impact might receive greater attention in degraded
remnants in fragmented landscapes, where risks to existing taxa
are lower and where such introductions would build upon existing
interventions designed to enhance regional biodiversity (Fischer et
al., 2006; Lindenmayer et al., 2010).
A
B
C
Fig. 1. Contrasting types of assisted colonisation. In (a) specific species assisted colonisation – a specified taxon threatened with decline under climate change is moved
(‘pushed’) into one or more optional recipient sites where future persistence is predicted to be high. In (b) ecological replacement assisted colonization – one or more taxa are
relocated (‘pulled’) to a specified recipient site to maintain or restore an ecosystem process and/or function in the recipient site that is declining due to climate change. In (c)
assisted colonisation is used to ‘push’ a threatened taxon into a recipient site, but in so doing restores an ecosystem process and/or function that is declining due to climate
change, thus achieving outcomes from options (a and b). Dark shading in arrows indicates whether the introduction is motivated by concerns about source populations (a;
push), recipient sites (b; pull), or both (c; push + pull).
174 I.D. Lunt et al. / Biological Conservation 157 (2013) 172–177
Existing decision support tools for assisted colonisation may
be relatively easily expanded to accommodate a goal of ecosys-
tem restoration. For example, the decision making framework
developed by Richardson et al. (2009) requires the addition
of diminished ecosystem function as a potential motivation for
undertaking assisted colonisation, plus the expansion of the con-
cept of ‘focal impact’ to include collateral benefits (not just col-
lateral impacts). Populating these frameworks for push + pull
assisted colonization will require a revised approach to the eval-
uation of potential impacts. For example, impacts that are gener-
ally considered as risks in assisted colonisation motivated to
benefit a threatened taxon would be considered as potential
benefits in movement of species to achieve ecosystem function.
In any risk evaluation, the relevant comparison is not of assisted
colonisation against the status quo, but assisted colonisation
against anticipated losses under continuing climate change
(Schwartz et al., 2009). The uncertainties inherent in assessment
of the scale and direction of climate change itself, and the vulner-
ability of species to that change, are key factors in assessment of
push assisted colonisation adaptation strategies. For assisted colo-
nisation designed to have push + pull impacts, additional uncer-
tainties occur in relation to the potential for selected taxa to
establish self-perpetuating populations that contribute to ecologi-
cal function at a site within an appropriate time frame.
If assessments reveal that the benefits of undertaking either
assisted colonisation option outweigh the risks, then the question
becomes one of timing of implementation and monitoring of im-
pacts. McDonald-Madden et al. (2011) present a quantitative
framework to guide when to move species in push assisted coloni-
sation activities, based on population dynamics in the source hab-
itat, predicted dynamics in recipient sites, the cost of relocation
and species recovery potential. Additional factors need to be con-
sidered to accommodate push + pull assisted colonisation, includ-
ing the predicted dynamics of declining ecosystem processes, the
thresholds at which major change may occur, and the need to bal-
ance the delivery of the ecological function with the climate suit-
ability for the selected species. Development of success criteria
for evaluation of push assisted colonisation is relatively straight-
forward (Burbidge et al., 2011). For push + pull assisted colonisa-
tion there is the added challenge of monitoring for the continued
delivery of an ecological function with the potential complexities
of interdependences among biotic and abiotic components of the
ecosystem.
Further consideration needs to be given to the economic costs
and benefits associated with all forms of assisted colonisation. This
paper has emphasized the ecological value of species in sustaining
ecosystem services and supporting species interactions. These ser-
vices have economic value as well. For example, species that pro-
Table 1
Example functions potentially vulnerable to climate change that could be enhanced by assisted colonisation.
Functional issue for ecosystem Description Example(s)
Loss of keystone species Keystone species interact strongly with other
functions and generate a cascade of ecological
services
Many forests and woodlands in Australia are dominated by long-lived
Eucalyptus trees. These dominant, ‘foundation’ species control functions and
processes including stand structure and micro-climate, water and nutrient
cycling and fire behavior (Manning et al., 2006). Species replace each other
across climatic gradients so readily lend themselves to assisted colonisation
in anticipation of climate change
Five species of prairie dogs Cynomys spp. have a strong influence on the
functioning of grassland ecosystems in North America but have declined by
98% in the last 200 years (Hoogland, 2006). The existence of climate-related
relictual populations (Mead et al., 2010) suggests natural dispersal has been
too slow to keep up with historical climate change. There may be potential
to assist movement of different prairie dog species to retain ecosystem
services as future climates change
Loss of a unique ecosystem service Provision of ecosystem services with low
ecological redundancy that support the
persistence of other species
Larvae of the endangered European longhorn beetle affect a profound
change on the microstructure of the bark of the wild oak, enabling numerous
other endangered insects to flourish in the beetle’s presence (Buse et al.,
2008). Assisted colonisation of the European Longhorn beetle could generate
collateral benefits to invertebrate fauna at the recipient site
Sheep grazing is an essential to conservation of the Chalkhill Blue butterfly
Polyommatus coridon in the UK (Brereton et al., 2008). If conditions become
too warm for existing races of sheep on the downs, there are several others
that could be brought in as replacements (Gibbons and Lindenmayer, 2002)
Loss of a function that has a time
lag to effectiveness
Functions that take decades or longer to establish
and become effective
Tree hollows provide nesting habitat and retreat sites in almost all forest
types, with approximately 10–31% of reptiles, amphibians, birds and
mammals utilizing tree hollows in Australian ecosystems (Gibbons and
Lindenmayer, 2002). Declining tree species could be replaced with warmer-
or drier-adapted species
Biological control agent becoming
increasingly ineffective in a
changing climate
Species whose introduction to a recipient
ecosystem could prevent or reduce the invasion
of undesired species
Lesser St John’s Wort beetles are effective biological control agents in cold
climates but need to be replaced with Great St John’s Wort beetles for
effective St John’s wort (Hypericum perforatum) control in Mediterranean
climates (Schöpsa et al., 1996)
Increasing temporally mismatch of
resources
Functions that fill temporal resource gaps driven
by climate-driven phenological shifts
Plant species flowering at various times of the year provide resources for
pollinators. Banksia baxterii is one of the few plants that flower in autumn in
south western Australia and is major nectar resource for vertebrate
pollinators, particularly honey possums, a distinct lineage of marsupials. It is
vulnerable to increasing temperature (Yates et al., 2009) and may need to be
replaced by other autumn flowering plants
Maintenance of co-dependence
among species
Functions provided by one species that both
maintain and depend on functions provided by
other species
Terrestrial orchids have strong mutualistic dependence on pollinators that
tends to be site specific (unlike the mutualism with fungi; Waterman et al.,
2011) so that neither orchid nor pollinator could be moved without the
other. Similarly many pollinators have a host of other specializations that
would also need to be considered in assisted colonisation (Pemberton, 2010)
I.D. Lunt et al. / Biological Conservation 157 (2013) 172–177 175
mote pollination services might increase agricultural value. To our
knowledge, no one has investigated economic outcomes from as-
sisted colonization, but it may be possible for particular species
and ecosystems.
This conceptual integration of push + pull motivations in as-
sisted colonisation activities may help to reinforce synergies be-
tween the contrasting theoretical frameworks that underlie the
two approaches (Fig. 2). Push assisted colonisation draws heavily
on single-species population biology, invasion ecology, and an
extensive literature on management of threatened species and
small and declining populations (Simberloff, 1998; Parker et al.,
1999; Purvis et al., 2000). By contrast, push + pull assisted coloni-
sation has stronger theoretical foundations in landscape and resto-
ration ecology at ecosystem scales (Noss, 1990; Fischer et al., 2006;
Hobbs and Cramer, 2008; Lindenmayer et al., 2008). From an inva-
sion ecology perspective, introduction of a high impact taxon is
usually seen as inherently undesirable, whereas introduction of a
functional dominant is commonly viewed as a critical component
of a successful restoration strategy. Clearly, a wide range of intel-
lectual traditions will need to be drawn upon to manage assisted
colonisation effectively and safely within climate change adapta-
tion strategies for biodiversity conservation.
4. Conclusions
We emphasise that we are not promoting the adoption of any
particular assisted colonisation strategy, and we advocate that all
assisted colonisation activities must be subject to comprehensive
risk assessments and ongoing monitoring and management.
However, we encourage ecologists and managers to consider
how assisted colonisation could be adopted to achieve broader
goals than the persistence of a single, or just a few, threatened
species.
Acknowledgements
The perspective presented in this paper was developed at a
workshop on assisted colonisation supported by the Terrestrial
Biodiversity Adaptation Research Network of the National Climate
Change Adaptation Research Facility (NCCARF) in Australia.
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... Indeed, different forms of conservation translocations exist, all of which are increasingly recognised as viable means to enhance the resilience of threatened species, improve ecosystem integrity, and assist migration to favourable habitats [25,[27][28][29][30]. Firstly, "reintroductions": aim to re-establish viable populations of a focal species within their historical range but from which they have become extirpated or extinct [15]. ...
... In terms of actual translocations by year (Fig. 6), we can observe a similar trend to that of This increase in research output may be an indirect response to the increasing pressures currently facing many animal and plant populations [65], in that in the number of performed conservation translocations are increasing because it is seen as a viable way of enhancing the resilience of threatened species [25,27,66], and thus publications have increased by consequence. ...
Article
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Background Ecosystem degradation, mainly through overexploitation and destruction of natural habitats, is a well-known threat to the viability and persistence of many species’ populations worldwide. The use of translocations as a viable conservation tool in conjunction with protected areas has been rapidly increasing over the last few decades. Protected areas such as strict nature reserves, national parks, and species management areas continue to be central tools for biodiversity conservation as they provide vital habitats set aside from various human pressures. Because action consistently runs ahead of policy, the need for a clearer evidence base on the outcomes of wildlife translocations undertaken at a global scale is becoming increasingly urgent for scientific and decision-making communities, in order to build clear strategy frameworks around conservation translocations. We therefore conducted a systematic mapping exercise to provide an overview of the existing evidence on the outcomes of wildlife translocations in protected areas. Methods We searched two bibliographic databases, four web-based search engines with search-by-key-words capacity, 5 specialist websites, and conducted a grey literature call through two project stakeholders. We screened articles by title, abstract, and full text using pre-defined inclusion criteria all the while assessing the consistency of the reviewers. All relevant translocations were coded from retained publications. Key variables of interest were extracted and coded for each translocation event. The quantity and characteristics of the available evidence and knowledge gaps/clusters are summarised. The distribution and frequency of translocations are presented in heat- and geographical maps. Review findings A total of 613 articles were considered eligible for coding bibliometric data. Metapopulation management and review articles were not coded for quantitative and qualitative variables. Linked data (duplicated translocations) were also excluded. Finally, 841 studies of different translocation events were fully coded from 498 articles. Most of these translocations were carried out in North America and Oceania. The most commonly undertaken intervention types were one-off supplementations and “supplemented reintroductions”. Mammals were by far the most transferred group among animals. Magnoliopsida was the most translocated plant group. Survival, space use, and demography metrics were the most studied outcomes on translocated species. Conclusions This systematic map provides an up-to-date global catalogue of the available evidence on wildlife translocations to, from, or within protected areas. It should enable protected area managers to better understand their role in the global network of protected areas, regarding translocation practice, both as suppliers or recipients of translocated species. It may help managers and practitioners make their own choices by comparing previous experiences, regarding both the species concerned and the precise translocation modalities (number of individuals, etc . ). Finally, it constitutes a decision-making tool for managers as well as for policy makers for future translocations.
... There are many strategies to conserve threatened animal species, some more drastic (e.g. assisted colonisation; Lunt et al., 2013) or more costly (e.g. ecosystem restoration; Strassburg et al., 2019) than others. ...
Article
While the imminent extinction of many species is predicted, prevention is expensive, and decision-makers often have to prioritise funding. In democracies, it can be argued that conservation using public funds should be influenced by the values placed on threatened species by the public, and that community views should also affect the conservation management approaches adopted. We conducted on online survey with 2400 respondents from the general Australian public to determine 1) the relative values placed on a diverse set of 12 threatened Australian animal species and 2) whether those values changed with the approach proposed to conserve them. The survey included a contingent valuation and a choice experiment. Three notable findings emerged: 1) respondents were willing to pay $60/year on average for a species (95% confidence interval: $23 to $105) to avoid extinction in the next 20 years based on the contingent valuation, and $29 to $100 based on the choice experiment, 2) respondents were willing to pay to reduce the impact of feral animals on almost all presented threatened species, 3) for few species and respondents, WTP was lower when genetic modification to reduce inbreeding in the remaining population was proposed.
... The rate of climate change continues to accelerate, and it is uncertain how many species will be able to shift quickly enough to track their climatic niche across increasingly human-dominated landscapes (Schloss et al., 2012). This has led some scientists to advocate new and bold approaches, such as assisted translocation (Lunt et al., 2013). For species which require large-scale interventions, public attitudes are likely to be important, particularly in densely populated areas or where there is potential conflict (O'Rourke, 2014). ...
Article
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The global redistribution of species due to climate change and other anthropogenic causes is driving novel human–wildlife interactions with complex consequences. On the one hand, range‐shifting species could disrupt recipient ecosystems. On the other hand, these species may be contracting in their historic range, contributing to loss of biodiversity there. Given that arriving range‐shifting species could also perhaps have positive effects on recipient ecosystems, there is [in principle] a net benefit equation to be calculated. Thus, public opinion on these species may be divided and they may present a unique challenge to wildlife management. We surveyed the opinion of wildlife recorders about the establishment and management of eight birds and eight insects whose ranges have recently shifted into the United Kingdom. We asked whether respondents' attitudes were explained by the species' or respondents' characteristics, and whether or not climate change was emphasised as a cause of range‐shift. We also conducted qualitative analysis of the recorders' text responses to contextualise these results. Attitudes to range‐shifting species were mostly positive but were more ambivalent for less familiar taxa and for insects compared with birds. Respondents were strongly opposed to eradicating or controlling new range‐shifters, and to management aimed to increase their numbers. Whether climate change was presented as the cause of range‐shifts did not affect attitudes, likely because respondents assumed climate change was the driver regardless. These findings suggest that it will be difficult to generate support for active management to support or hinder species' redistribution, particularly for invertebrate or overlooked species among wildlife recorders. However, the positive attitudes suggest that on the whole range‐shifting species are viewed sympathetically. Engaging with wildlife recorders may represent an opportunity to garner support for conservation actions which will benefit both currently native and arriving species, such as improvements to habitat quality and connectivity. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog.
... Increased availability of spatially explicit paleoclimatic models and data, along with enhanced molecular tools capable of testing more refined phylogeographic hypotheses, has made the investigation of the effects of climate history more readily available (Lawing, 2021;Svenning et al., 2015). Paleoclimatic legacies have important implications for biodiversity conservation as they identify (1) where species might experience climatically stable refugia worthy of long-term protection (Ackerly et al., 2010;Loarie et al., 2009), and (2) which species may not be able to track climate changes via migration due to biogeographic constraints or humanimpacted areas (Bertrand et al., 2011;Lunt et al., 2013). Answering these questions for S. tergeminus is critical because of the fragmented nature of its populations and threats to its grassland habitat. ...
Article
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The western massasauga (Sistrurus tergeminus) is a small pit viper with an extensive geographic range, yet observations of this species are relatively rare. They persist in patchy and isolated populations, threatened by habitat destruction and fragmentation, mortality from vehicle collisions, and deliberate extermination. Changing climates may pose an additional stressor on the survival of isolated populations. Here, we evaluate historic, modern, and future geographic projections of suitable climate for S. tergeminus to outline shifts in their potential geographic distribution and inform current and future management. We used maximum entropy modeling to build multiple models of the potential geographic distribution of S. tergeminus. We evaluated the influence of five key decisions made during the modeling process on the resulting geographic projections of the potential distribution, allowing us to identify areas of model robustness and uncertainty. We evaluated models with the area under the receiver operating curve and true skill statistic. We retained 16 models to project both in the past and future multiple general circulation models. At the last glacial maximum, the potential geographic distribution associated with S. tergeminus occurrences had a stronghold in the southern part of its current range and extended further south into Mexico, but by the mid‐Holocene, its modeled potential distribution was similar to its present‐day potential distribution. Under future model projections, the potential distribution of S. tergeminus moves north, with the strongest northward trends predicted under a climate scenario increase of 8.5 W/m2. Some southern populations of S. tergeminus have likely already been extirpated and will continue to be threatened by shifting availability of suitable climate, as they are already under threat from desertification of grasslands. Land use and habitat loss at the northern edge of the species range are likely to make it challenging for this species to track suitable climates northward over time. The western massasauga (Sistrurus tergeminus) is a small pit viper with an extensive geographic range, yet they persist in patchy and isolated populations, threatened by habitat destruction and fragmentation, mortality from vehicle collisions, and deliberate extermination. Changing climates may pose an additional stressor on the survival of isolated populations. Here, we evaluate historic, modern, and future geographic projections of suitable climate for S. tergeminus to outline shifts in their potential geographic distribution and inform current and future management.
... The primary objective of a conservation translocation is to preserve population, species or ecosystem diversity (IUCN, 2013) through the creation or bolstering of genetically diverse populations. Conservation translocations may be required in response to co-occurring pressures such as climate change (Vitt et al., 2010;Lunt et al., 2013), genetic and reproductive isolation (Weeks et al., 2011;Frankham, 2015) and habitat isolation and fragmentation (Monks and Coates, 2002;Dalrymple et al., 2012). One high profile, characteristic example of a conservation translocation is Wollemia nobilis (Wollemi Pine), which has been translocated to protect wild populations from threats of disease, climate, local population collapse and a single stochastic event, such as fire, impacting the entire population (Mackenzie et al., 2021). ...
Article
Full-text available
Translocation of plants is used globally as a conservation action to bolster existing or establish new populations of threatened species and is usually communicated in academic publications or case studies. Translocation is also used to mitigate or offset impacts of urbanization and development but is less often publicly published. Irrespective of the motivation, conservation or mitigation, on ground actions are driven by overriding global conservation goals, applied in local or national legislation. This paper deconstructs the legislative framework which guides the translocation process in Australia and provides a case study which may translate to other countries, grappling with similar complexities of how existing legislation can be used to improve accessibility of translocation records. Each year, across Australia, threatened plants are being translocated to mitigate development impacts, however, limited publicly accessible records of their performance are available. To improve transparency and opportunities to learn from the outcomes of previous mitigation translocations, we propose mandatory recording of threatened plant translocations in publicly accessible databases, implemented as part of development approval conditions of consent. The contribution to these need not be onerous, at a minimum including basic translocation information (who, what, when) at project commencement and providing monitoring data (outcome) at project completion. These records are currently already collected and prepared for translocation proposals and development compliance reporting. Possible repositories for this information include the existing national Australian Network for Plant Conservation translocation database and existing State and Territory databases (which already require contributions as a condition of licensing requirements) with new provisions to identify and search for translocation records. These databases could then be linked to the Atlas of Living Australia and the Australian Threatened Plant Index. Once established, proposals for mitigation translocation could be evaluated using these databases to determine the viability of mitigation translocation as an offset measure and to build on the work of others to ensure better outcomes for plant conservation, where translocations occur.
... proposals for translocations to restore ecosystem functions (e.g., IUCN 2013; Aslan et al. 2014) have been the subject of substantial discussion of potential risks and benefits (Nogués-Bravo et al. 2016;Rubenstein and Rubenstein 2016;Fernández et al. 2017;Pettorelli et al. 2018;Perino et al. 2019). Lunt et al. (2013) have compared possible risks and benefits of translocations to restore ecosystem functions and translocations to address climate change, pointing to the possibility of addressing both goals simultaneously. To employ proposed decision tools and adhere to the International Union for Conservation of Nature (IUCN) guidelines, both advocates and critics increasingly agree that progress is required on more accurate risk assessments and on characterization, categorization, and quantification of the environmental impacts of translocations , as has occurred with the Environmental Impact Classification for Alien Taxa (EICAT) framework Hawkins et al. 2015;Evans et al. 2016), which has been adopted as an IUCN standard (IUCN 2020), and similarly for socioeconomic impacts, as has begun under the socio-economic impact classification of alien taxa (SEICAT) framework (Bacher et al. 2018). ...
... Pelai et al. 2021). The idea of moving a species beyond its historical range to keep pace with changing climatic conditions is increasingly being considered as an adaptation option (Lunt et al. 2013;Vitt et al. 2016;Wang et al. 2019). Such prospects raise several daunting challenges for protected areas, including problems associated with translocations (Batson et al. 2015) and with the uncertainty of managing translocations in a context of unexpected consequences (Dudney et al. 2018;Schuurman et al. 2020), especially where there is already a negative bias due to previous impacts from humantransported invasive species (Richardson et al. 2020). ...
Article
Full-text available
Horizon scanning is increasingly used in conservation to systematically explore emerging policy and management issues. We present the results of a horizon scan of issues likely to impact management of Canadian protected and conserved areas over the next 5–10 years. Eighty-eight individuals participated, representing a broad community of academics, government and nongovernment organizations, and foundations, including policymakers and managers of protected and conserved areas. This community initially identified 187 issues, which were subsequently triaged to 15 horizon issues by a group of 33 experts using a modified Delphi technique. Results were organized under four broad categories: ( i) emerging effects of climate change in protected and conserved areas design, planning, and management (i.e., large-scale ecosystem changes, species translocation, fire regimes, ecological integrity, and snow patterns); ( ii) Indigenous governance and knowledge systems (i.e., Indigenous governance and Indigenous knowledge and Western science); ( iii) integrated conservation approaches across landscapes and seascapes (i.e., connectivity conservation, integrating ecosystem values and services, freshwater planning); and ( iv) early responses to emerging cumulative, underestimated, and novel threats (i.e., management of cumulative impacts, declining insect biomass, increasing anthropogenic noise, synthetic biology). Overall, the scan identified several emerging issues that require immediate attention to effectively reduce threats, respond to opportunities, and enhance preparedness and capacity to react.
... Explaining the variable response to novel site conditions observed here is important for choosing sites for ex situ conservation efforts like managed relocation, which may be necessary to ensure ginseng viability in a changing climate . Although managed relocation has been debated extensively from ethical and theoretical perspectives (Lunt et al., 2013;Minteer & Collins, 2010;Ricciardi & Simberloff, 2009;Richardson et al., 2009;Sax et al., 2009), few have tested its success empirically (but see (Willis et al., 2009). The Field transplant Experiment 1 illustrates how local adaptations to both climatic and nonclimatic environmental factors can affect the efficacy of managed relocation. ...
Article
As climates change, species with locally adapted populations may be particularly vulnerable as specialization narrows the range of conditions under which populations can persist. Populations adapted to local climate as well as other site‐specific characteristics like soils present challenges for inferring how changing climates affect fitness, as climatic and nonclimatic variables that constitute local conditions decouple. We conducted two transplant experiments involving American ginseng to test how climatic conditions affect performance while controlling for effects of other site characteristics. We first out‐planted populations from differing elevations to gardens arrayed along an elevation/climate gradient. We also grew maternal plants under temperatures corresponding to home‐site and future conditions (16.4–22.4°C), transplanting resultant progeny to two home‐sites at different elevations (400 m, 800 m). Source populations responded idiosyncratically to elevation reflecting how nonclimatic site characteristics strongly affected plant fitness. Germination rates declined for seeds from maternal plants exposed to warmer temperatures, which compounded with diminished seed production of maternal plants, suggested that population growth may decline rapidly as warm years become hotter and more frequent. Controlling for maternal temperature effects provided evidence that plants are adapted to home‐site conditions, both climatic and nonclimatic, with population growth rates for out‐planted populations ranging from below population replacement levels (λ = 0.58) to well above (λ = 1.33). Evidence of local adaptation to climatic and nonclimatic environmental components, in combination with negative fitness impacts of warming climates on offspring via maternal effects, suggests that changing climate may imperil ginseng and other similar understory species. Growth of populations transplanted to similar climates at novel sites was idiosyncratic. Both mid‐ and high elevation populations exhibited the highest population growth in the mid‐elevation transplant site, while performance diverged at the high elevation site in a pattern suggesting home‐site advantage. All transplant sites supported ginseng populations prior to establishment of transplant gardens, and were selected due to similarly in vegetative composition and soil characteristics to home‐sites of transplanted populations. Despite this, population growth rates varied between 0.58–1.33 highlighting the challenge of appropriate site selection for ex situ conservation in response to change climate.
... Alternatively, their prey species, or native species affected by habitat change, are sheltered from feral species' negative impacts by exclusion-fencing (Legge et al., 2018) or by taking populations into captivity (Harley et al., 2018). There is also a possibility of moving negatively impacted wildlife to other, safer sites using assisted migration (Lunt et al., 2013), which is more commonly considered in terms of climate adaptation than avoiding feral animals. We tested public preferences for the following approaches: (i) killing feral animals directly, (ii) managing feral animals without harming them using fire and weed control, (iii) excluding feral animals using fences, (iv) moving native species to a new location away from the feral animal threat or (v) taking native species into captivity. ...
Article
Conservation management is a rapidly evolving field in which scientific innovation and management practice can run ahead of social acceptability, leading to dispute and policy constraints. Here we use best-worst scaling (BWS) to explore the social preferences for two broad areas of threatened species management in Australia as well as support for extinction prevention as a whole. Of the 2430 respondents to an online survey among the Australian general public, 70% stated that extinction should be prevented regardless of the cost, a sentiment not fully reflected in existing policy and legislation. There was strong support for existing measures being taken to protect threatened species from feral animals, including explicit support for the killing of feral animals, but the demographic correlations with the results suggest approval is lower among women and younger respondents. There was a particularly high level of support for moving species to new places, which does not match current capabilities of managers responsible for assisted migration, suggesting messaging about the current limitations needs to be improved, or for resources to overcome them greatly increased. There was less support for genetic interventions than the feral animal control and other land management measures. A small majority of respondents thought it would be better for a species to cope without assistance than invasively alter their genome. This suggests that greater community consultation is desirable before applying genetic management approaches more interventionist than interbreeding subspecies.
Preprint
Current species’ range displacements are mostly triggered by climate change but European landscapes are largely dominated by human activities. In this study we identify the most promising spatial adaptive trajectories (SATs) for the thirty most threatened non volant mammal species in Europe up to 2080 (under three climate and land change scenarios) and where/when SATs of each species synchronically converge. We found large contrasts on the persistence of species in SATs, with some species largely reliant on the functionality of areas where many SATs converge. Overall, SATs and convergence centers are not adequately covered by existing conservation areas and coincide with crop and arable lands, compromising species persistence. It is important to invest in the protection of SATs and convergence centers through a mix of conventional instruments and new collaborative forms with the socio-economy. Anticipative plans at long-term coupled with risk analysis offer decision–makers templates to prevent negative surprises.
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Species composition of prey consumed by spotted hyaenas Crocuta crocuta in three divergent areas in southern Africa was determined by scat analyses. The larger abundant antelopes predominated in the diet and their occurrence in the diet was apparently directly related to the availability of the prey within the hyaena foraging areas. In Mkuzi' Game Reserve and the Namib Naukluft National Park, hyaenas coexist with only one other large predator. In Umfolozi Game Reserve, where hyaenas coexist with four other large predators, a greater variety of prey was taken. Scat weight in desert-dwelling hyaenas was twice that of those from more mesic areas, which may be an adaptation to restricted water intake. The incidence of domestic livestock in the diet was meagre, probably the result of collecting scats only from latrines within the game reserves. Die spesies-samestelling van prooi verbruik deur gevlekte hienas Crocuta crocuta in drie verskillende gebiede in Suidelike Afrika is bepaal deur faeces-analise. Die groter meer volop wildsbokke het die dieet gedomineer en die voorkoms in dieet toon 'n direkte verwantskap met beskik­ baarheid van prooi in hiena-jaggebiede. Hienas deel Mkuzi Wildtuin en die Namib Naukluft Nasionale Park met slegs een ander groot roofdier terwyl vier ander groot roofdiere Umfolozi Wildtuin met hienas deel, wat lei tot groter variasie in prooi-items. Faeces-massa van woestynlewende hienas ..,as twee keer meer as die van hienas in meer mesiese gebiede wat waarskynlik 'n aanpassing is vir beperkte water inname. Die voorkoms van plaasdiere in die dieet was baie laag, maar dit is heel waarskynlik as gevolg van faeces­ versameling slegs binne die wildtuine.
Book
More than 300 species of Australian native animals — mammals, birds, reptiles and amphibians — use tree hollows, but there has never been a complete inventory of them. Many of these species are threatened, or are in decline, because of land-use practices such as grazing, timber production and firewood collection. All forest management agencies in Australia attempt to reduce the impact of logging on hollow-dependent fauna, but the nature of our eucalypt forests presents a considerable challenge. In some cases, tree hollows suitable for vertebrate fauna may take up to 250 years to develop, which makes recruiting and perpetuating this resource very difficult within the typical cycle of human-induced disturbance regimes. Tree Hollows and Wildlife Conservation in Australia is the first comprehensive account of the hollow-dependent fauna of Australia and introduces a considerable amount of new data on this subject. It not only presents a review and analysis of the literature, but also provides practical approaches for land management.
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1. Ecological factors influencing prey selection by tiger Panthera tigris, leopard Panthera pardus and dhole Cuon alpinus were investigated in an intact assemblage of large mammals in the tropical forests of Nagarahole, southern India, between 1986 and 1990. 2. Densities of large herbivores were estimated using line transects, and population structures from area counts. Carnivore diets were determined from analyses of scats (faeces) and kills. Selectivity for prey species was inferred from likelihood ratio tests comparing observed counts of scats to hypothesized scat frequencies generated from prey density estimates using parametric bootstrap simulations. Predator selectivity for size, age, sex and physical condition of prey was estimated using selection indices. 3. Ungulate and primate prey attained a density of 91 animals km-2 and comprised 89-98% of the biomass killed. Predators showed significant (P
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Canada regenerates more than 400 000 ha of forest land annually through planting and seeding operations. Much of the stock for this effort is selected to be climatically suited to the planting site-a match that is often facilitated through the development of seed zones. However, if climate change proceeds as predicted, stock that is well matched under current climate will be growing in sub-optimal conditions within the next 20 to 50 years-in some parts of the country, trees may already be growing outside their optimal climates. To provide a sense of the magnitude of these changes, we present past and predicted future climate trends for Ontario and British Columbia seed zones. For Ontario, over the period 1950 to 2005, minimum temperature of the coldest month has already increased by up to 4.3°C, growing season has lengthened by up to 6 days, and precipitation during the growing season has increased by up to 26%. Changes were more pronounced across British Columbia's Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) seed zones, with minimum temperature increasing by up to 8°C, a growing season extension of up to 30 days, and growing season precipitation increases of up to 40%. Projections for the end of the current century include: minimum temperature increase of 5°C to 10°C, growing season extension of 31 to 60 days, and growing season precipitation increases of 3% to 42% across the seed zones in both provinces. These changes are certain to have extensive impacts on forest ecosystems. We briefly discuss 3 forest management adaptation strategies intended to mitigate the negative impacts of climate change in Canada.
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The predator-prey aspects of four cheetah (Acinonyx jubatus) groups were studied in Nairobi National Park, Kenya, from October, 1966, through February, 1967. Hunt:kill ratios were applied to direct observation data of 157 hunts and 30 kills. Hunting success apparently varied with habitat-type, prey species, sex and age-classes of prey, herd size, cheetah group size, and the cheetah's or group's hunting experience. Cheetah kills appeared to be other than a random sample of prey populations. There was differential selection in prey of females and juveniles.
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African wild dog (Lycaon pictus) predation was observed in Ngorongoro Crater, Tanzania, between September, 1964, and July, 1965, when packs were in residence. The original pack of 21 dogs remained only 4 months, but 7 and then 6 members of the group reappeared in the Crater at irregular intervals. The ratio of males:females was disproportionately high, and the single bitch in the small pack had a litter of 9 in which there was only one female. The pack functions primarily as a hunting unit, cooperating closely in killing and mutual defense, subordinating individual to group activity, with strong discipline during the chase and unusually amicable relations between members. A regular leader selected and ran down the prey, but there was no other sign of a rank hierarchy. Fights are very rare. A Greeting ceremony based on infantile begging functions to promote pack harmony, and appeasement behavior substitutes for aggression when dogs are competing over meat. Wild dogs hunt primarily by sight and by daylight. The pack often approaches herds of prey within several hundred yards, but the particular quarry is selected only after the chase begins. They do not run in relays as commonly supposed. The leader can overtake the fleetest game usually within 2 miles. While the others lag behind, one or two dogs maintain intervals of 100 yards or more behind the leader, in positions to intercept the quarry if it circles or begins to dodge. As soon as small prey is caught, the pack pulls it apart; large game is worried from the rear until it falls from exhaustion and shock. Of 50 kills observed, Thomson's gazelles (Gazella thomsonii) made up 54 percent, newborn and juvenile wildebeest (Connochaetes taurinus) 36 percent, Grant's gazelles (Gazella granti) 8 percent, and kongoni (Alcelaphus buselaphus cokei) 2 percent. The dogs hunted regularly in early morning and late afternoon, with a success rate per chase of over 85 percent and a mean time of only 25 minutes between starting an activity cycle to capturing prey. Both large and small packs generally killed in each hunting cycle, so large packs make more efficient use of their prey resource. Reactions of prey species depend on the behavior of the wild dogs, and disturbance to game was far less than has been represented. Adult wildebeest and zebra (Equus burchelli) showed little fear of the dogs. Territorial male Thomson's gazelles, which made up 67 percent of the kills of this species, and females with concealed fawns, were most vulnerable. The spotted hyena (Crocuta crocuta) is a serious competitor capable of driving small packs from their kills. A minimum of 4-6 dogs is needed to function effectively as a pack. It is concluded that the wild dog is not the most wantonly destructive and disruptive African predator, that it is an interesting, valuable species now possibly endangered, and should be strictly protected, particularly where the small and medium-sized antelopes have increased at an alarming rate.