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A Human Security Framework for the Management of Invasive NonindigenousPlantsAuthor(s): Andrew J. Tanentzap, Dawn R. Bazely, Peter A. Williams, and Gunhild HoogensenSource: Invasive Plant Science and Management, 2(2):99-109. 2009.Published By: Weed Science Society of AmericaDOI: http://dx.doi.org/10.1614/IPSM-08-127.1URL: http://www.bioone.org/doi/full/10.1614/IPSM-08-127.1

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Invited Review

A Human Security Framework for theManagement of InvasiveNonindigenous Plants

Andrew J. Tanentzap, Dawn R. Bazely, Peter A. Williams, and Gunhild Hoogensen*

Few individuals or governments have suggested that invasions by nonindigenous species are relevant to the broader

issue of human security, despite a growing awareness of the ecological, economic, and societal impacts associated

with invasive nonindigenous species (INIS). We propose that by framing management actions in a human and

environmental security context, the threats (and benefits) posed by INIS to individuals and communities can be

explicitly articulated and debated. This framework allows multiple stakeholders to bring their concerns to bear upon

specific policy, and attempts to integrate broad environmental concerns within its parameters. We use the case of

ecosystem-based management of invasive nonindigenous plants as an example of the utility of a human security

framework. The dominant management approach to these species remains focused on the individual species, despite

increasing calls for the implementation of ecosystem-based management strategies. Ecosystem-based management is

supported by generalized and widely accepted mechanisms of plant community dynamics, such as succession,

disturbance, and interspecific competition, but these scientific arguments do not consistently carry weight at the

policy level and with the broader public. A human security framework may provide an approach for overcoming this

resistance by placing the debate over management within the social and political context of the wider community.

Overall, human security can allow applied ecologists to be better positioned to meet the challenges of

communicating the need for science-based management.

Key words: Communication, ecosystem-based management, policy, single-species, stakeholder engagement.

Growing global awareness of the broad environmental,social, and economic impacts of invasive nonindigenousspecies (INIS) has resulted in an increased attention beingpaid to invasion ecology (Simberloff 2004). It is widelyaccepted that INIS have the potential to result insubstantial social and economic impacts (Lounibos 2002;Meyerson and Reaser 2002; Mooney and Hobbs 2000;Perrings et al. 2000, 2002; Pimentel et al. 2000; Soule1990) by altering the functioning of natural systems at thegenetic, species, community, and ecosystem level (Gordon

1998; Myers and Bazely 2003; Walker and Smith 1997;Williamson 1996). Although exceptions may exist, e.g., thefiltering of eutrophic water by zebra mussels in the GreatLakes may economically outweigh the cost of controllingthe mussels (Brown et al. 2007), INIS have the potential tothreaten ecosystem services as well as economic and socialvalues that directly affect human security and wellbeing.Both the mainstream media and scientific literature nowregularly address the impacts of biological invasions. AGoogle News (http://news.google.com) search for the term‘‘invasive species’’ for August 2008 returned over 1,600newspaper articles. Individuals and governments worldwidehave responded to the issue with a number of initiativesadvocating an agenda for invasive species management.However, the issue is dominated by slow-moving, if not alack of, action, particularly in North America (Kerr et al.2005; Reichard et al. 2005; Simberloff et al. 2005). Wesuggest that it is therefore timely to consider the link thatexists between the fields of invasive species and humansecurity.

DOI: 10.1614/IPSM-08-127.1

* First author: Department of Plant Sciences, University of

Cambridge, Downing Street, Cambridge CB2 3EA, U.K.; second

author: Department of Biology, York University, 4700 Keele Street,

Toronto, Ontario M3J 1P3, Canada; third author: Landcare

Research, Private Bag 6, Nelson, New Zealand; fourth author:

Department of Political Science, University of Tromsø, 9037

Tromsø, Norway. Corresponding author’s E-mail: ajt65@cam.ac.uk

Invasive Plant Science and Management 2009 2:99–109

Tanentzap et al.: Human security and invasives N 99

Despite a growing awareness of the problems posed byINIS, few individuals or governments have suggested thatthese invasions are relevant to the broader issue of humansecurity. This is in contrast to other environmental issuesthat have emerged on both political and security agendas(Brown 1977; Dalby 2002; Dodds and Pippard 2005;Gleditsch 1997; Myers 1986). The threats posed toindividuals by climate change are, perhaps, the most clearlydeveloped case in which ecological change has been directlylinked to human security (Brauch et al. 2008; Symon et al.2005). Although there has been criticism of expandinghuman security to include a ‘‘laundry list’’ of concerns(King and Murray 2002; Paris 2001), the threats on thislist have developed their own large and evolving academicliteratures (e.g., environmental security; Dalby 2002). Inthis paper, we provide a framework that allows invasionbiologists to articulate our field with respect to its policyrelevance and to contribute to political and securityagendas within broader discussions about environmentaland human security. Using the example of ecosystem-basedmanagement of invasive nonindigenous plants, we dem-onstrate how cooperation between natural and socialscientists can better inform policy makers and society ofthreats to human and environmental security, in a mannerthat may increase the likelihood of achieving morescientifically based management actions. We argue thatgiven the theory underlying mechanisms of plant invasions,that ecosystem-based management is more appropriatethan species-specific approaches. However, ecosystem-based management is often less likely to be implemented,and this may reflect some resistance from policy makersand the broader public toward science-based argumentsand the difficulty in applying management strategies todynamic systems across spatial and temporal scales(Christensen et al. 1996).

What is Human Security and Why Should

Ecologists Care?

The notion of human security is often debated injuxtaposition to state security, which focuses on protectingthe state from existential threats that can lead to full-scaleconflict and potentially change borders and regimes, suchas attacks by terrorists or foreign invasion (Buzan et al.1998; Fierke 2007; Walt 1991). The environment, letalone INIS, has historically been perceived as a nonissue inthis context. However, dissatisfaction with the narrownessof traditional security has led to a widening of this concept(Brown 1977; Burgess and Owen 2004; Dalby 2002;Myers 1986). Since the 1970s, environmental issues havemade their way onto security agendas; first in terms ofprotection of resources for the state, and later movingbeyond state security concerns and recognizing thatprotection of the actual environment, rather than the state,

should be the focus of environmental security (Hoogensen2009). These developments in environmental security wereinfluential in acknowledging the importance of a widersecurity agenda, in which the security of nonstate or non–government agency stakeholders, and their dependence onthe environment, also became relevant, leading first policyand then theory to the concept of human security(Hoogensen 2009). It was recognized by the UnitedNations and countries comprising the Human SecurityNetwork (www.humansecuritynetwork.org) that hunger,disease, and natural and environmental disasters actuallypresent a greater potential cause of human sufferingand death than state security concerns (Tadjbakhsh andChenoy 2006; UNDP 1994). An entire conceptualframework has consequently developed around humansecurity that encompasses health, food safety, andenvironmental security (UNDP 1994), along with threatsto the political, economic, personal, and societal or self-identity security of individuals and communities (e.g.,Burgess and Owen 2004; Dodds and Pippard 2005;Hoogensen 2008).

To date, there is little agreement on the definition ofhuman security. Instead, key overarching features areaccepted that can be advantageously defined dependingon the context in which human security is applied. Theprimary feature of human security is a focus on theindividual: ‘‘The world can never be at peace unless peoplehave security in their daily lives.’’ (UNDP 1994, p. 1).Another feature is the range of issues it embraces, includingmilitary-related, but largely nonmilitary security concerns,such as food, health, and environmental security. As such,human security attempts to bridge a number of securityperspectives by identifying their value and relevance to theindividual. In fact, the entire field of security studies, withits broad range of issues and multi-scale approaches,ranging from the individual to the state to global, can beseen to parallel the multi-scale framework of ecology inwhich we examine ecological interactions at the levels of theindividual, population, community, and ecosystem, and atdifferent spatial scales. Human security, in particular,illustrates the connectivity between scales and values, andhas posed a serious challenge to traditional views of state-centered, political boundary–driven security that arebecoming increasingly debated (Dalby 2002).

The human security concept is frequently contested inthe arenas of policy, diplomacy, and justice. Academics inthe fields of security studies and international relations havealso hotly debated the value and effectiveness of the conceptsince its popularization in 1994, arguing that humansecurity should have a narrowly bounded scope because thebroader concept is too dilute for directing policy andproviding concrete action (King and Murray 2002; Paris2001). Nevertheless, the concept has demonstrated bothtraction and staying power, not only surviving more than a

100 N Invasive Plant Science and Management 2, April–June 2009

decade of mixed successes but also finding much of itsapplication through the development of environmentalsecurity (Brauch et al. 2008, 2009; Dodds and Pippard2005; Homer-Dixon 1999; Hough 2004). Recent publi-cations have moved on from viewing environmentalsecurity as being exclusively concerned with armed conflictover limited resources, such as water and oil, andincorporate such topics as sustainable land use strategy(e.g., Petrosillo et al. 2008). This shift is reflected in thedefinition of environmental security as creating theconditions that support life by not only mitigating militarydamage to the environment and environmentally inducedconflicts but also protecting the environment because of itsinherent moral value (Glenn and Gordon 2007). In thisrespect, environmental security has shifted from a largelythreat-based security concept (identifying state-basedthreats and merely mitigating against them) to a positive‘‘security creating’’ concept by establishing structures suchas laws and management plans that ensure the security ofthe environment and the human beings who rely upon it.

Implementing a Human Security Framework

The developments in environmental security, whichwould include INIS research, are well represented throughthe human security model because it allows for (1) theconcerns of stakeholders to influence the policies thatattempt to regulate and mitigate the potential threatshuman and ecological systems pose to one another and (2)facilitation of the opportunities and security these samestakeholders can productively exploit (Figure 1). Tradi-tionally, many of the recommended research-based ap-proaches to the management of INIS by scientists and landmangers (researchers), who are part of this framework,might not be implemented because different stakeholderspossess different security perspectives. The purpose of the

human security model is to identify competing orcomplementary security perspectives (instead of focusingon one dominant perspective) and allow a framework ofdialogue upon which possible compromises and solutionscan be based (Figure 1). When a human security approachis applied, the result is that multiple stakeholders expresstheir concerns in a discourse that aims not to be dominatedby any one particular view, thus allowing previouslymarginalized stakeholders to have a voice (Figure 1).

The benefit of the human security debate has been tohighlight and make visible the concerns and valuesarticulated by individuals and communities that haveotherwise not been adequately addressed through state-basedsecurity approaches. A central issue associated with thehuman security approach, however, has been to identifythese concerns and values within contexts that do not includelarge-scale conflicts. The work and research conducted onINIS clearly have impacts on the concerns and values ofhuman communities, and we wish to explicate theserelationships using a human security approach. Humansecurity does not replace INIS management, but rather,provides a context for understanding the impacts of INIS onhuman communities, as well as prioritizing these impactsagainst other human security issues that may conflict withthe needs of INIS management, e.g., economic well-being.

For INIS, human security would provide support for thedevelopment of management strategies by prioritizingobjectives and defining management success with respectto the interests and values of individuals and communities.The need to determine goals and define success is anessential component of developing management strategies(NISC 2005) and this can be particularly challenging whenthese definitions are based solely upon ecological responses(Palmer et al. 2003). In New Zealand, pest managementstrategies are required to prioritize all of the potentialimpacts of a species on human security, including human

Figure 1. A model of human security (adapted from Hoogensen, 2008). All lines denote communication (and possible conflictingsecurity perspectives) among stakeholders (communities or individuals, researchers, policy makers, the military, media, and businessesor industries) in human security. Arrows are omitted where necessary for clarity. The dashed line represents the role of the state-securities perspective.

Tanentzap et al.: Human security and invasives N 101

health, indigenous culture, agro-forestry, and indigenousecosystems. Under New Zealand’s National Pest PlantAccord (NPPA), species are identified for evaluation fromthe monitoring programs of regional councils and otherpublic submissions, and assessed for classification as anational-level biosecurity threat by industry and regionaland national government based on the potential to invadenatural habitats and the threats posed to componentsof human security (Champion 2005). The goal of theNPPA is to prevent further sale or distribution oflisted species, without explicitly defining success aspreventing the establishment or expansion of naturalizedpopulations. Ultimately, a human security frameworkwould not outline how management should proceed norremove the requirement for monitoring the success ofmanagement.

Human security differs from conventional stakeholderengagement because it not only facilitates a discussionamongst interested parties but also attempts to (1) engagethe broader society that may be affected by many of theissues being discussed and (2) actively address the concernsof all stakeholders. As opposed to stakeholder engagement,where parties initiating the outreach identify stakeholders apriori, e.g., government agencies seeking public participa-tion in land management plans, human security aims toinclude the broadest range of voices and opinions. Bydeveloping a process in which individuals have a role asboth stakeholders and as creators of security (albeit unequalin power), traditional and more powerful stakeholders ofsecurity (policy makers and the military) are no longerperceived as the only providers of security. Although thisstructure may or may not consist of a process of mediationamong stakeholders, it defines security from multipleperspectives that need to be consolidated in managementactions. Such an approach has been taken on U.S. militarybases, where the threats posed by INIS to human securityare also considered as threatening the broader operationaland strategic interests of state security providers (West-brook et al. 2005). High-ranking U.S. government officialsand departments responsible for state security have alsopromoted the relationships between environmental andhuman security, including through the establishment of aCentral Intelligence Agency unit to assess the role of theenvironment in national and regional level instabilities thatmay affect U.S. interests (Foster 2001). Despite thecreation of the U.S. Department of Homeland Security(DHS) in response to the state security threats posed by thefactors responsible for the events of September 11, 2001,the importance of environmental and human security tostate security providers has not disappeared. The recentinclusion of the DHS within the National Invasive SpeciesCouncil and the Council’s most recent management plan(NISC 2008) suggest increasing participation by DHS tomanage INIS and communicate with state governments,

local communities, academic researchers, and businessesand industry.

Ecosystem-Based Management of INIS: An Example

of the Need for a Human Security Framework

The majority of research into the management ofinvasive nonindigenous plants has been published in thelast 10 years, and it is evident that in North America, themost common management approaches focuses on thespecies level (Table 1). This contrasts with more holisticapproaches that explicitly account for how ecologicalprocesses and mechanisms are linked to the theoreticalfoundation of invasion ecology, and are occasionallyadvocated elsewhere, such as in New Zealand (e.g.,Atkinson 2001; Owen 1998; Williams 1997; Williamsand West 2000) and in the field of restoration ecology(Hobbs and Norton 1996). Ecosystem-based managementstrategies, such as prescribed burning and grazing, are morechallenging to implement and success is more difficult todetermine for ecosystem-level objectives (Christensen et al.1996; Simberloff 1998). Ecosystem-based management isalso less likely to receive broad public support than species-led strategies, perhaps because of the perception thatmanagement actions having broader impacts will be morelikely to have unintended consequences (e.g., escaped fires,soil erosion). Biological reasons for adopting a scaled-upapproach include the importance of maintaining long-termsustainability through ecological integrity, and the recog-nition that ecosystems are both holistic and dynamic unitsthat are profoundly impacted by humans (Arkema et al.2006; Christensen et al. 1996; Grumbine 1994, 1997). Aparadigm shift away from species-specific approaches andtoward ecosystem-based management has been occurring inthe last two decades for several fields: resource and wildlandmanagement (Galindo-Leal and Bunnell 1995), weedmanagement in rangeland systems (Sheley and Krueger-Mangold 2003), and restoration ecology projects followinglarge-scale invasions (Hobbs and Norton 1996) and landabandonment (Standish et al. 2008).

We propose that a perceptual shift toward ecosystem-based management of invasive nonindigenous plant speciesis highly desirable and justified, given the ecological basis ofplant invasions. The demography and ecology of individualpopulations are dependent on the holistic, community, andecosystem-based theories of vegetation succession, distur-bance, and interspecific competition (Figure 2). In fact,themes of invasion are fundamental to the emergence of thefield of plant community ecology, and vice versa (e.g.,successional changes and competition associated withnonnative Russian-thistle (Salsola tragus L.) in Nebraskain the late 1890s), and many of these concepts form theunderlying theoretical basis that informs most currentthinking in invasive plant ecology (Figure 2). Species-

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specific approaches may be applicable only early in thestages of invasion when all individuals of a species can betargeted, although this still requires consideration ofecosystem-based processes and mechanisms (Zavaleta etal. 2001). Additionally, INIS can directly alter ecosystemprocesses such that the establishment and proliferation ofthe invasive species itself, and even additional newcomers,are promoted (Simberloff and Von Holle 1999). Themodification of ecosystems by such keystone INIS candrive ecosystems to alternate states (e.g., Baiser et al. 2008;Mack and D’Antonio 1998; Standish et al. 2008). Forexample, invasion of the Sonoran desert by fire-tolerantnonindigenous grasses downy brome (Bromus tectorum L.),red brome (Bromus rubens L.), and common Mediterraneangrass [Schismus barbatus (Loefl. ex L.) Thell.] leads toincreased fire frequency that negatively affects less fire-tolerant native species (Brown and Minnich 1986).Management strategies aimed solely at removing theseinvasive species will fail in restoration under thesecircumstances. Similarly, the invasion of riparian zones inthe southwestern United States by nonindigenous saltcedar

(Tamarix spp.) increases soil salinity and alters hydrologicalregimes (DiTomaso 1998), displacing less-competitivenative species less tolerant of arid, saline conditions (Glennet al. 1998; Vandersande et al. 2001). Restorationapproaches that address the ecosystem properties that arealtered by Tamarix spp. (i.e., salinity, pH, and groundwa-ter availability), rather than solely removing individualTamarix spp. plants, are more likely to successfully restorenative species and control future invasions (Bay and Sher2008).

The benefits of early control and prevention ofwidespread establishment far exceed the risks and costsassociated with managing a widespread invasion (Williams1997). Species-specific approaches should focus only on theprevention of transportation and establishment becauseestablished populations affect, and are affected by, entireecosystems. Ecosystem-based management should becomeimportant during the establishment phase of invasion(Figure 3), because the establishment of invasive species isunlikely to be successfully prevented by targeting anindividual species with either manual or chemical control,

Table 1. Primary literature searches for articles recommending species-specific or ecosystem-based management of invasivenonindigenous species outside of and within North American from 1998 to 2007, and from 1948 to 1997. Values report number ofarticles recommending a specific strategy and corresponding percentages.

All taxa (including plants) Plants

Non-North America North America Non-North America North America

1998–2007 Strategya

Species-specific 85 51% 152 59% 70 48% 138 57%

Ecosystem-based 57 34% 59 23% 54 36% 59 24%

Integrative (species and ecosystem) 25 15% 45 18% 23 16% 44 18%

Total number of papers recommendingmanagement 167 256 147 241

1948–1997 Strategy

Species-specific 26 62% 25 76% 15 50% 20 77%

Ecosystem-based 12 29% 2 6% 12 40% 1 4%

Integrative (species and ecosystem) 4 10% 6 18% 3 10% 5 19%

Total number of papers recommendingmanagement 42 33 30 26

a In order to compare the relative occurrence of the three management strategies, we constructed a database of articles indexed in theISI Web of Science (http://portal.isiknowledge.com) up to and including December 2007 with the following keyword searches: (1)(‘‘species led’’ OR ‘‘species specific’’ OR herbicide OR biocontrol OR bio-control OR pulling) AND (management OR control) AND(inva* OR introduced OR alien OR exotic OR non-native OR non-indigenous); and (2) (‘‘ecosystem based’’ OR ‘‘ecosystem basedmanagement’’ OR burning OR grazing OR mowing) AND (management OR control) AND (inva* OR introduced OR alien ORexotic OR non-native OR non-indigenous). After considering only articles in the top 70 journals for each search based on the numberof returns (top 85 in the case of search 2 due to the presence of ties), 126 journals remained in our database for a total of 1,382 articles.We classified articles based on whether the authors recommended a species-specific or ecosystem-based approach to management. Weacknowledge that just because ecologists recommend a species or ecosystem based management approach, managers are not necessarilyimplementing this strategy on the ground. Rather, we assume that because managers are likely to follow the recommendations ofecologists in developing management plans for invasive nonindigenous species, the recommended strategies are likely to beimplemented.

Tanentzap et al.: Human security and invasives N 103

and likely to be caused by ecosystem attributes thatpromote invasion. However, because humans respondstrongly only when they perceive crisis, early control isfrequently neglected. Spotted knapweed (Centaurea macu-losa auct. non Lam.; 5 C. stoebe L. ssp. micranthos (Gugler)Hayek), a virulent invader of western North Americangrasslands, is an example of such misfocused management.The suppression of summer burns in Midwestern grass-lands due to human intervention furthers the success ofinvading C. maculosa (Emery and Gross 2005). Commonlyused control tactics focusing only on manual removal orherbicide application (Rice et al. 1997; Sheley et al. 1998,2000) target the symptom of invasion, the presence of C.maculosa, rather than the cause of invasion, human-mediated fire suppression.

Transferring Research Recommendations Into Policy

Rational scientific arguments do not always carry weightat the policy and public level. Applied biologists repeatedly

articulate their frustration with the time lag between thereporting of research results and management recommen-dations in the literature, and the implementation of thisinformation in policy (Benton et al. 2007; Lodge andShrader-Frechette 2003; Rosenstrom and Lyytimaki 2006;Stevens 2001). Although some of the difficulty in translatingresearch into policy may be a result of the challenge thatpolicy makers face in resolving the inherent uncertainty inwhich ecology is rooted (Ludwig et al. 2001), research fromacross the natural and social sciences shows that there is aknowledge mobilization gap of at least 10 years betweenpeer-reviewed research being conducted and being imple-mented at broader societal levels (Heher 2006).

Can ecologists reach the point where ecosystem-basedmanagement of invasive species becomes normal practice?We suggest that by placing invasive species in a humansecurity framework, ecologists and land managers willincrease the likelihood of garnering broad-based supportfor ecosystem-based management. Human security isimplicit in New Zealand’s biosecurity legislation, which

Figure 2. Chronology of development of some of the major concepts in invasive (white) and community (grey) plant ecology. 1Bessey1893; Bessey and Weber 1890; Pound and Clements 1898; 2Clements 1916, 1928; 3Elton 1927; Grinell 1914, 1917; 4Clements 1916;Cooper 1913; Gleason 1926; Watt 1924; 5Hutchinson 1944, 1957; MacArthur and Levins 1967; 6Elton 1958; 7Curtis and McIntosh1951; Egler 1954; Whittaker 1967; 8Grubb 1977; 9Coley 1983; Coley et al. 1985; Feeny 1976; Rhoades and Cates 1976; 10Connell1980; Davis et al. 2000; 11Connell and Slatyer 1977; Grime 1974, 1977, 1979; Tilman 1985; 12Blossey and Notzold 1995;13Simberloff 1995; 14Davis et al. 2005; 15Simberloff and Von Holle 1999; 16Callaway and Ridenour 2004; 17Fridley et al. 2007.

104 N Invasive Plant Science and Management 2, April–June 2009

aims to protect the country’s biodiversity and manageeconomic and human health risks (e.g., Biosecurity Act1993, Hazardous Substances and New Organisms Act1996 [Parliament of New Zealand 1993, 1996]). To date,this has been relatively successful at preventing andcontrolling economically significant INIS (Jay et al.2003). Invasive non-indigenous plants were largely regard-ed as a rural problem prior to this legislation despite therole nonrural communities play in their establishment andspread. The Biosecurity Act encourages rural and urbaninterests to collectively identify INIS for management,creating dialogue among stakeholders for whom INIS maypose distinctly different threats, and whom policymakersdid not view as connected prior to this legislation. Similarlegislation may further benefit from explicitly consideringhuman security, which requires other stakeholders, includ-ing state security providers, to engage in discussions aboutINIS.

Successful management of INIS depends largely oncooperation between scientists and society as a whole. Theability to build a coalition of private and publicstakeholders around management issues will usuallydetermine success. Lodge and Shrader-Frechette (2003)identify this as the major challenge facing the riskmanagement of INIS. Restoration ecology, for example, afield in which INIS management occurs, is increasinglypracticed because it is seen as a process in which humanvalues are managed equally with natural systems (Higgs

1997). In contrast, the failure of the environmentalmovement to have their message accepted in full may bedue to the inability of environmentalists to engageindividuals outside of their field (Shellenberger andNordhuas 2004). We believe that a similar barrier existsto the social acceptance of ecosystem-based managementwithin the broader population, especially within NorthAmerica. Restoration ecology has confronted this challenge(Hobbs et al. 2004) and succeeded in adopting ecosystem-based approaches to control INIS. Addition of the term‘‘restor*’’ to our search databases (Table 1) found that 67%of restoration ecology studies that successfully identifiedstrategies to control INIS were conducted in NorthAmerica (n 5 85), and ecosystem-based strategiespredominated both in North America (ecosystem-based5 37%; species-specific 5 30%; integrative 5 33%), andglobally (ecosystem-based 5 38%; species-specific 5 33%;integrative 5 29%).

Ecosystem-Based Management in a Human

Security Framework

We propose that the placement of the issue of invasivespecies in a human security framework will assist inaddressing the knowledge-mobilization challenges faced byecologists and habitat managers concerned with INIS. Thisconceptual and action-oriented framework allows for thearticulation of the pros and cons of various management

Figure 3. Relative importance of species-specific (hatched line) and ecosystem-based (solid line) strategies to control nonindigenousspecies throughout the stages of invasion (adapted from Williams 1997). Once an invasive species becomes entrenched, managementefforts should be diverted towards mitigating (dotted line) the impact of invasion. The light grey lines give the location of Williams’(1997) original model, and the arrow identifies our suggested shift in intersection between strategies to an earlier stage in invasion, fromthe ‘‘Explode’’ stage to the ‘‘Expand’’ stage.

Tanentzap et al.: Human security and invasives N 105

actions in terms of their threats and benefits to society,thereby directly linking ecological systems to social, orhuman, systems. The inherent focus on human rights inthe human security framework should increase the capacityto overcome the sort of polarization that often arises withmany management actions, i.e., prescribed burning orgrazing. Because human security is both a policyinstrument and a conceptual tool, it can provide a meansfor overcoming inertia due to regional and culturaldifferences in human values. Human security also allowsarguments about INIS to be more clearly articulated thandebates rooted in an ecological or philosophical context,such as the intrinsic worth of biodiversity, by widening thediversity of involved stakeholders, which demands alterna-tive, accessible communication and knowledge delivery.Such an approach would increase the knowledge andawareness of all stakeholders while not relying solely on thepotentially alienating language of peer-reviewed ecologicalstudies and vegetation succession theory, which may beperceived as abstract and inaccessible by government andpolicy makers. Consequently, we suggest that the humansecurity framework provides a means of making abstruseinvasion science more accessible.

One example that encompasses all of the ideas we presentin this review is giant hogweed (Heracleum mantegazzianumSommier & Levier), which is widely considered to be one ofthe most widespread and problematic INIS in Europe.Heracleum mantegazzianum invasion displaces native plantspecies at multiple spatial scales (Pysek et al. 2008) withinhuman-disturbed sites with relatively weak competitors(Pysek and Pysek 1995; Thiele and Otte 2006). Matureplants pose a significant health risk for humans due to thewidespread occurrence within tissue of furanocoumarinsthat can induce severe chemical burns upon contact withskin and subsequent exposure to ultraviolet light (Lagey etal. 1995). Erosion of riparian areas from senescent winteringindividuals and the harboring of agricultural pests andpathogens can also negatively affect economic interests(Caffrey 1999; Page et al. 2002). In Germany, the estimatedannual cost of H. mantegazzianum invasion is at least $17million (Reinhardt et al. 2003). The breadth of research onH. mantegazzianum and translation of these results intopublic awareness has generated high levels of public supportfor management actions in Scotland (Bremner and Park2007), and in New Zealand, H. mantegazzianum has beenclassified as a biosecurity threat through the NPPA becauseof its potential to invade natural habitats and its impacts onhuman health (Derraik 2007). Although it remains to beseen whether public and policy recognition of the threatsimposed by H. mantegazzianum will lead to ecosystem-based management, we believe that the human securitymodel (Figure 1) can more rapidly lead to managementapproaches that best address current and future INISthreats.

Conclusions

Human security is, from an ecological and sciencecommunication perspective, a framework for engaging in abroader, political-social discussion of ecological issues such asINIS. By operating at both grassroots and high political levels,the multi-stakeholder framework of human security willrequire that ecologists connect with the broader communityover stories that convey the threats and benefits of invasivespecies and how individuals may be personally affected (e.g.Shellenberger and Nordhaus 2004). The familiarity thatecologists have with the need to consider and work with multi-scale data makes us well suited to relate to the human securityconcept. However, the actions of individuals are key infacilitating species introductions. Small-scale managementapproaches that focus on individual species or sites can serve asthe basis for engaging local communities and define largermanagement schemes, wherein individuals have a clearerunderstanding of their role towards a larger, collectivedefinition of success. Weed awareness programs promotedby countries such as New Zealand and Australia are examplesof this approach. The Council of Australasian Weed Societiespresents annual awards to commercial nurseries that volun-tarily remove invasive nonindigenous plants from their stock,sell indigenous flora, and educate consumers about invasivenonindigenous plants, thereby encouraging local-scale partic-ipation to collectively address the broader goals of national-level biosecurity legislation (DOC 2004). Establishing similarlinks between individual actions and the broad-scale ecosystemconsequences that promote invasions by nonindigenousspecies (‘‘think globally, act locally’’) remains the challenge.

Acknowledgments

We thank A. L. Smith, N. D. Yan, D. A. Coomes, C.Dionigi, and two anonymous reviewers for helpful commentsand discussion that greatly benefited the development of ourmanuscript.

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