Introduction

1«Don’t judge species on their origins» asserts a group of 18 ecologists in a 2011 article in Nature. This pithy vindication problematising the «pervasive bias against alien species» that characterises conservation approaches to non-native species struck a nerve within the invasion sciences and was followed over the next two months by a series of fervent «letters», «correspondence», and «comments» in the journals Nature and Science (Davis et al, p. 153). As a field that designates, appraises and manages ecological outsiders and insiders, the invasion sciences are no strangers to dispute. While conflicts within the field have historically centred on the tensions between researchers and members of the public about «the nature and magnitude of problems posed by the invaders, and the best ways to deal with them, » contemporary disputes like this one have begun to take a more introspective turn, examining the very foundations of the field—notably the language (and embedded values) used to describe and codify ecological migrants (Shine and Doody, 2011, p. 400).

2I have chosen to explore this contemporary dispute because, as Brante asserts, controversies «constitute particularly fruitful research sites, for during [them] the contending parties scrutinize each other’s arguments and assumptions with exceptional care» (1993, p. 186). As explanatory and generative phenomena, controversies have the power to simultaneously expose deep cultural commitments, biases and factions and to generate new ones. And because knowledge production does not exist in a vacuum, the ideas circulating within a disciplinary dispute both emanate from and will inevitably have consequences for the societies in which they take place. What is more, as the «post normal» scientific discipline (Funtowicz and Ravetz, 1993) that most informs contemporary environmental thinking, management, policy and activism, we cannot overestimate the significance of ecology in producing knowledge and meaning about our planet. And, as the «crisis discipline» (Soulé, 1985) that has tasked itself with solving the urgent problem of species invasions, the invasion sciences are a domain of knowledge production that have regular and significant impacts on communal understandings of what constitutes ecological insiders and outsiders and the appropriate modes of managing them.

3While scholars from various disciplines have begun to explore the language and management of «invasive speciesv (e.g. Davis, 2006; Davis, 2011; Groning et al, 2004; Head and Muir, 2004; Holm, 2012; Johnson, 2010; Larson, 2011; Olwig, 2003; Selge and Fischer, 2011, Stanescu et al 2016), scholars of environmental communication have yet to systematically investigate this important domain of knowledge production. Inspired by this gap in the literature and the benefits of environmental communication research in addressing complex and pressing environmental problems (Druschke and McGreavy, 2016), this study offers a rhetorical analysis of the 2011 dispute in the invasion sciences.

Rethinking belonging on a novel planet

4We live in a moment characterized by heightened attention to belonging. The contemporary amplification of deep-seated crises—migration, climate change, species extinction, populism, and racial inequity—has laid bare the persistent and problematic legacies of colonial senses of place. Far more than «a set of economic, political, and military phenomenon,» imperialism «was a complex ideology which had widespread cultural, intellectual and technical expressions in the era of European world supremacy» (MacKenzie, 1990, p. vii). One of the most significant expressions of imperial power was its rethinking and reordering of the natural world. In addition to fundamentally altering the political, economic, geographic, and social fabric of much of the world, European colonialism transformed nature, «creating new landscapes, new ecologies and new relations between human and non-human naturev (Adams and Mulligan, 2004, p. 1). According to William Mark Adams and Martin Mulligan, the «destructive, utilitarian and cornucopian view of the feasibility of yoking nature to economic gain» was a direct result of Enlightenment ideas about the natural world, most notably the Cartesian dualism between mind-matter and, by extension, culture-nature and emerging economic models of nature-as-resource (2004, p. 23). This is not to glorify or overlook pre-colonial ideas about, and interactions with, the natural world but rather to acknowledge that European colonial processes instigated both major shifts in thinking about the natural world and the technological capacities to change that world on a scale and rate heretofore unimaginable.

5The «Anthropocene», both as popular symbol and scientific argument, embodies an emergent collective reckoning with modern humans’ destructive ideas about, and relationships with, the natural world; ideas and relationships accelerated and cemented by European colonialism. Though most indicators of the «Anthropocenev point to 1950 as bearing the visual markers of a new epoch, these markers are of course manifestations of earlier events and processes. In spite of the fact that it has not yet been officially recognized as a unit of geological time, the «Anthropocene» has taken on a life of its own in academic and popular discourses. One key reason for its popularity may be its foundation in «ecological novelty,» an umbrella term recognizing the unprecedented, human-mediated changes that now shape all aspects of the earth’s ecology. In beginning with «novelty,» the «Anthropocene» is a rejection both of contemporary attempts to manufacture uncertainty surrounding anthropogenic climate change and the often well-meaning conservative impulse in politics, culture and science to advocate and legislate for a nostalgic return to an imagined precolonial world where everything and everyone are «in their place». From the «Anthropocene» there is no going back.

6The present dispute within invasive ecology—indeed the discipline itself—is positioned within these larger political, cultural, ecological, and epistemic shifts. As a discipline invested in designating and policing ecological belonging, the invasion sciences are an ideal site for inquiry that have obvious and important environmental, social and political implications. Foremost because their subjects—so-called invasive and non-native species—are themselves tropes for the problems and possibilities of our times; tropes that turn our attention to the vital questions: What and who belongs? What constitutes boundaries and when, where and how do we cement them? Who decides? And, ultimately, how do we imagine, represent and thereby manage belonging on a complex and dynamic planet? Using rhetorical methods to analyse the 2011 dispute in the field of invasion ecology, this study reveals the enduring albeit latent legacies of colonial discourses in the ecological and invasion sciences.

Theoretical frameworks

Environmental discourses

7The past 25 years have witnessed increasing interdisciplinary attention to the importance of language in the social construction of the natural world (Eskridge and Alderman, 2010). Diverse fields of inquiry from geography to political science have become increasingly receptive to the insights provided by discursive approaches to the natural world and its epistemic communities (e.g. Dryzek, 1997 and Hajer, 1995). At the same time, researchers in the field of communication have employed their toolkit to study representations of nature and the natural world. Discursive approaches to the environment investigate the ways in which meanings about the «environment» and «nature» are constructed, mobilized, and disseminated, as well as how they are challenged and transformed. This essay builds upon several contemporary strands in environmental communication research including: the interdisciplinary turn, which asserts that environmental issues require «collaborations across diverse institutional and disciplinary boundaries» and «environmental communication scholarship is critical to the success of sustainability science [and initiatives]» (Lindenfeld et al. 2012, p. 23); studies in the rhetoric of «risk,» «uncertainty,» and «crisis» (e.g. Cox, 2007, Heath and O’Hare, 2010); studies exploring the public mediation and understanding of science (e.g. Gross, 1994, Bauer et al, 2007); and the rhetoric of science and scientific controversy.

The rhetoric of science and scientific controversies

8The rhetoric of science is a subfield of rhetorical studies that examines the rhetorical features of knowledge production in the scientific disciplines. Rhetorical critics assert that «scientists are engaged in the process of persuasion in all of their professional and intellectual activities, not only in the forum, but also in the laboratory, the field, and the study» (Gross, 1994, p. 3). The seeds for discursive studies of science were planted by American philosopher of science, Thomas Kuhn, whose The Structure of Scientific Revolutions provided a sociological account of the ways in which science is produced, maintained, and disrupted. In opposition to the pervading logic of the time, Kuhn asserted that science does not develop «progressively»but rather in the form of what he called «revolutions». According to Kuhn, «normal science» is conservative and is produced through communities of researchers who, sharing a common disciplinary framework, a paradigm, engage in clearing up puzzles created by anomalies in the paradigm. Whereas most anomalies are resolved by incremental change or by revealing errors in observation or experimentation, the build-up of unresolved anomalies over a period of time leads on rare occasions to a challenge of the paradigm altogether. At this point, says Kuhn, the disciplinary matrix enters a period of crisis characterized by «a proliferation of compelling articulations, the willingness to try anything. The expression of explicit discontent, the recourse to philosophy and to debate over fundamentals» (1962, p. 91). The crisis is resolved by a new paradigm; hence revolution. While Kuhn’s broad account of the revolutionary character of scientific knowledge production provoked more questions than answers, there is no denying the fundamental impact his work has had on the sociological study of science. The shifting understanding of science—from neutral, transparent, objective and authoritative, to value-laden, cultural and rhetorical—has been advanced and nuanced by scholars across the academy including Paul Feyerabend, Michel Foucault, Thomas Gieryn, Jurgen Habermas, Bruno Latour, Karl Polanyi, Karl Popper, C.P. Snow, Richard Rorty, and Stephen J. Toulmin. And while «ceasing to see [the scientist] as priest» has helped to democratize knowledge production, mediation and application, it has also had the unwitting side effect of being abused by powerful interests who mobilize «uncertainty» and «relativity» to political and financial gain (in Harris, 1997, p. xvii).

9To study science from a rhetorical perspective is to concede the powerful role of science as a major institution of knowledge production and to explore the relationship between language, knowledge and action (e.g. policy, management, behavior). The subfield was first articulated in Philip Wander’s (1976) article «The rhetoric of science» and grew rapidly in the 1980s alongside two associated areas: the rhetoric of inquiry (ROI) and the interdisciplinary area science and technology studies (STS). Alan G. Gross’s (1990), The rhetoric of science and (1997) edited volume with William M. Keith, Rhetorical hermeneutics, as well as Randy A. Harris’s (1997) Landmark essays on the rhetoric of science showcase a decade of rhetorical insights on scientific practice and became the foundations for a new generation of rhetorical inquiry of science. Rhetorical studies of science are organized around three interrelated categories (Harris, 1997): scientific demarcation practices (e.g. Taylor, 1996), scientific genres, topoi and figures (e.g. Bazerman, 1997), and scientific controversies (e.g. Goodnight, 2005).

10Studies in rhetorical demarcation, genres and topoi explore and make visible the «complex but open-ended network of cultural practices» that constitute the «scientific ecosystemv (Taylor, 1996) as well as the rhetorical exigencies and features that constitute various genres of scientific communication. Studies range from the macro- to micro-level examining whole fields (e.g. Halloran, 1997) and alternately single texts (e.g. Ceccarelli, 2001) and from popular (e.g. Fahnestock, 1998) to technical (Myers, 1997). Research in this subfield can be synthesized into the following insights: First, science is demarcated by highly ritualized norms and conventions that are stable but may change in response to the shifting needs of communities and cultural moments. Second, scientific norms and conventions are constructed and mediated via rhetorical strategies and texts (e.g. textbooks, peer review, laboratory practices). And third, scientific knowledge is produced and mediated through a variety of symbolic practices (e.g. academic conferences and articles, science popularizations) and rhetorical appeals (e.g. ethos, pathos). Early rhetorical studies of science studies were based predominantly in the application of argumentation theory and Neo-Aristotelian theory and criticism; contemporary research is marked by its interdisciplinarity.

11Whereas early studies detailed the rhetorical dimensions of what Ceccarelli (2001) calls «prototypical scientific texts» (e.g. Bazerman, 1988, Campbell, 1997, Halloran, 1984, Myers, 1997), contemporary studies increasingly examine the diverse, hybrid, and often invisible genres of scientific communication through which science is made, mediated, debated and popularized (e.g. Ceccarelli, 2001, Miller, 2005). The rhetoric of scientific controversies is a contemporary line of research that examines the complex social, political and epistemic work being done by constituents in a scientific controversy. Constructed of diverse texts and artifacts, scientific controversies are rich sites for rhetorical inquiry because they bring to the surface the oft invisible commitments, practices, stakeholders and relationships in scientific phenomena, research, and applications. In this way, scientific controversies are not just about science; they are about our cultures, our values, and our beliefs (Lyne, 2005). As such, they are ideal texts for rhetorical study because they reveal the latent entanglements between science and society. And rather than highlighting some longstanding clash between competing parties, scientific controversies underscore the ways in which all discourses are complex rhetorical hybrids embedded in diverse, and often contradictory, ways of being and seeing in the world (Miller, 2005). Studies in the rhetoric of scientific controversies explore the unique texts, stakeholders, exigencies and rhetorical strategies that characterize contemporary scientific controversies (e.g. Fahnestock, 1997, Lyne and Howe, 1986). Not surprisingly, many of these studies identify the important function of «uncertainty» in the rhetorical construction, maintenance and negotiation of scientific controversies (e.g. Ceccarelli, 2011 and Michaels and Monforton, 2011).

Methodological approach

12As a rhetorical critic, I am interested specifically in how texts in this dispute frame the debate: Which issues are included and emphasized? Which are excluded or obfuscated? How do the medium and audience influence the contours of the debate? And, how do these rhetorical fetures mediate and frame belonging? In order to explore these questions I used «close textual-intertextual analysis» described by Ceccarelli as «a close reading not only of the primary text but also of the intertextual material produced by audience members who were responding to it» (2001, p. 8). According to the author, this methodology «provides a more reliable connection between internal form and external function» (p. 8). Close textual-intertextual analysis is amenable to the study of scientific controversies generally, constituted as they are by multiple texts, and more specifically to what Engelhardt and Caplan (1987) term «complex controversies,» those scientific controversies with heavy political and ethical overlays.

13As an analysis corpus, this essay examines the initial eight «comments,» «letters» and «correspondences» that constitute the early debate (including Davis et al’s June 2011 provocation in Nature and the seven direct responses to Davis et al in Nature and Science). I have chosen to draw the lines around these eight texts because they distil key positions and beliefs among key constituents and because, as «commentaries», they constitute a unique genre of scientific communication worthy of rhetorical analysis, and, taken together, they constitute the early dispute, in this case the «text». The debate began with Mark A. Davis et al’s (June 2011) «comment» in Nature’s June issue, «Don’t judge species by their origins». The following month Nature published four reactions to this piece in its «correspondence»section. The first correspondence, «Non-natives: 141 scientists object,» was led by prominent biologist David Simberloff (July 2011) and published alongside Alyokhin’s (July 2011) «Non-natives: Put biodiversity at risk,» Lockwood, Hoopes and Marchetti’s (July 2011) «Non-natives: Plusses of invasion ecology» and Lerdau and Wickham’s (July 2011) «Non-natives: Four risk factors». The dispute carried over into the «letters» section of Science with Lambertini et al’s (July 2011) «Invasives: A major conservation threat,» Marques’s (August 2011) «Invasives: A sea of data to come» and Moore’s (August 2011) «Invasives: Classify with care».

14The analysis was performed in two parts beginning with a historical contextualization of the primary text and followed with a close reading of the text and its reception over the next two months in seven response essays. The historical contextualization includes both a brief history of the study of invasive species as well as the «exigencies»that gave rise to Davis et al’s June 2011 «comment» in Nature. The close reading involved a textual analysis of the primary text followed by close readings of each text as it responded to Davis et als’ provocations.

Results and discussion

On the origin of species

15As is the case with many contemporary disciplines, invasion ecology emerged from a variety of older fields of inquiry including agriculture, biogeography, botany, entomology, forestry, natural history, pathology and zoology (Davis, 2006, Lockwood et al, 2013). Though not their central focus, scientists within each of these fields were grappling with the existence and effects of non-native species--a phenomenon that was in large measure a product of the «planting and displanting» central to European colonial expansion (Mastnak et al, 2014). The language of species «nativity» was first articulated by British botanist John Stevens Henslow and codified by British botanist, Hewett Watson, who in the mid-1800s drew upon the language and underlying philosophies of British colonial law and formally introduced the terms native, denizen, colonist, alien, and incognita in the sciences (Chew and Hamilton 2011). Over the next century, many researchers, including prominent scientists Charles Darwin, Charles Lyell, and Joseph Grinnell, researched and wrote about species nativity (Richardson 2011; Simberloff 2011). Indeed, according to Lockwood et al (2013), the list of scientists who have dabbled in the invasion sciences reads like an all-star roster of who’s who in the life sciences.

16As in other realms of cultural production, early modern scientists made use of the dominant frameworks of their time as they encountered and studied new subjects; and as part and parcel of British colonialism, these frameworks were often steeped in colonial ideas and constructs. This is not to suggest that the influence was one way; rather they informed each other. As historian John MacDonald Mackenzie asserts, «imperial power[…] and research in the natural sciences were closely dependent in the nineteenth century» (1990, p. vii). Natural history, early modern botany, and what would become ecology, each intimately supported and profited from European colonialism (Adams and Mulligan, 2004; Schiebinger and Swan, 2005). Drawing on pre-existing views of the colonial periphery, colonial scientific discourses and practices took possession of, institutionalised, and exported biological specimens in what Mastnak et al. have called «a massive operation of planting and ‘displanting’» (p. 364).

17Charles Elton’s (1958) The ecology of invasions by animals and plants marks the official birth of the discipline dedicated solely to the definition, identification, codification and management of «nativeness»and remains one of the most cited works in the field. The book’s 50^th anniversary in 2008 prompted a major conference on the topic and was likely central to contemporary introspection in the field and the 2011 dispute examined in this essay (Richardson, 2011).

18Invasion ecology is organised around two camps of thought: The Eltonian and the Asilomar. The Eltonian camp began with Charles Elton’s aforementioned publication. The Eltonian approach is management-oriented and is based upon the presupposition that non-native species are inherently problematic. Its founder, Charles Elton, viewed species «invasions» in the larger context of niches--the specialised roles species take in an intact, co-evolved ecosystem--viewing non-natives as inherently disruptive of the so-called natural harmony of such systems (Marris, 2009). The Asilomar camp was established in 1964 when the International Union of Biological Science held a symposium to explore the concept of species colonisations, including those mediated by humans. The resulting book, The genetics of colonizing species (1965) by Baker and Stebbins, has come to define this approach, which is theory- (as opposed to management) based and set in opposition to the Eltonian bias against non-native species.

19Beyond the two substantial works in the mid-twentieth century, invasive species research did not pick up again until the 1990s following the publication of the Scientific Committee on Problems of the Environment (SCOPE) volumes, which brought together a large group of ecologists from around the world to document the problems associated with invasive species (Lockwood et al, 2013). The following decade saw numerous conferences and sessions dedicated to the topic as well as the growth of conservation biology and restoration ecology, two fields centrally focused on the management of non-native species (Davis, 2006). According to Lockwood et al (2013), the language of the SCOPE volumes and the research that followed from it are characterized by an Eltonian view of invasions as major threats to biodiversity. Research at the turn of the century has continued in this vein with most studies focusing on the management, control and eradication of non-native species, especially as the effects of climate change on biodiversity and habitat destruction have become increasingly evident.

20The past 20 years has seen mounting criticism of dominant approaches to invasive species; most visibly by ecologist Mark A. Davis. One of Davis’s early and central concerns was the siloing of invasive ecology, which he believes would be better studied and managed within the larger framework of ecology. As he put it, «there is little about biological invasions that make them so unique that a specialized subdiscipline need be sustained to study them» (Davis, 2009). Davis’s 2009 textbook Invasion biology challenges much of the discipline’s conventional wisdom about non-native species from its basis in niche theory and related presuppositions about the relationship between native species and diversity, to its treatment of non-native species as both fundamentally different from natives and inherently problematic. On most accounts, Davis asserts the evidence does not bear out. What is more, he notes that most eradication efforts are costly and unsuccessful. His ultimate recommendation is nothing short of abolishing the discipline altogether. According to environmental writer, Emma Marris (2009), «Davis is not on the fringe. His arguments crystallize a rumbling of dissent recently heard among those who study invasive species» (p.327). This dissent is both pragmatic (the present toolbox cannot solve the perceived problems of invasive species) and philosophical (the perceived problems are rooted in cultural biases) (see Chew and Laubichler, 2003, Colautti and MacIsaac, 2004, Davis, Thompson and Grime, 2009, Larson, 2005, Woods and Moriarty, 2001). Brendon Larson’s (2005) article in Frontiers in Ecology, «The war of the roses: demilitarizing invasion biology»offers the most extensive critique of the effects of «militaristic and combative metaphors» in invasion ecology. The article was adapted into a larger book project, Metaphors for sustainability: redefining our relationship with nature (2011), that examines four feedback metaphors (including «invasional meltdown») in the sustainability sciences.

21This rumbling finally erupted with Davis et al’s June 2011 Nature commentary, «Don’t judge species on their origins». Highlighting the pervasive native-versus-alien species dichotomy, the authors claim that current management approaches, based in militant language that lends inevitably to eradication efforts, are often a poor use of resources and assert that it may be more sensible to use scarce resources for other conservation threats, such as habitat destruction and degradation. The essay was followed immediately by seven reaction letters and correspondences printed in Nature and Science over the next two months and a flurry of correspondence, essays and books addressing the problems and possibilities highlighted in this dispute over the next three years (e.g. Larson and Kuffer, 2013, Paolucci, MacIsaac and Riccardi, 2013, Ricardson and Ricciardi, 2013, Shackelford et al, 2013, Simberloff et al, 2012, Simberloff, 2013a, Simberloff, 2013b and Simberloff et al, 2013). The topic has also been popularised in recent years by science journalist, Elizabeth Kolbert in her 2014 New Yorker article, «The big kill: New Zealand's crusade to rid itself of mammals» as well as journalist Sonia Shah’s (2020), The next great migration: The story of movement on a changing planet.

The provocation: Don’t judge species on their origins

22Davis et al’s «Don’t judge species on their origins» spans two pages (just over 1400 words) and includes five images of «introduced species». The piece opens with a brief history of the 200 year scientific study of «nativeness» and follows with two sections, «biological bias» and «new guiding principles». The subheading states, «Conservationists should assess organisms on environmental impact rather than whether they are natives, argues Mark Davis and 18 other ecologists» (p. 153). The comment is directed at conservationists and land managers, (and by association invasion biologists) who, they assert, make management decisions based upon a longstanding and problematic commitment to the «native-versus-alien species dichotomy» and spoken from the standpoint of ecologists and uses the first person «we» on several occasions. The 19 coauthors represent some of the most well published and well recognized English-speaking ecologists in the area and unsurprisingly include one of the leading proponents of the concept of «novel ecosystems,» Richard J. Hobbs.

23The author’s central argument occurs midway through the article: «Classifying biota according to their adherence to cultural standards of belonging, citizen, fair play, and morality does not advance our understanding of ecology. Over the past few decades, this perspective has led many conservation and restoration efforts down paths the make little ecological or economic sense» (p. 153). Citing several examples, the authors contend that these cultural biases against non-natives have resulted in many futile, if not «counterproductive,» management actions. On several occasions throughout the article, the authors note the use of «apocalyptic threats,» «vilification» and «military metaphors» and «exaggerated claims of impending harm» as they influence public perception of non-native species. The authors advocate for management decisions based in «sound empirical evidence» rather than «unfounded claims of harm caused by non-natives» and encourage «dynamic and pragmatic» approaches that «embrace the fact of ‘novel ecosystems’»and even «incorporate alien species into management plans». The authors close stating «We are not suggesting that conservationist abandon their efforts to mitigate the serious problems caused by some introduced species. But we urge conservationists and land managers to organize priorities around whether species are producing benefits or harm to biodiversity, human health, ecological services and economies» (p. 154).

The reaction: Scientists and managers (mostly) object

24The following month (July 2011) Nature printed four reactions in the correspondence section (Simberloff et al’s «Non-natives: 141 scientists object,» Alyokhin’s «Non-natives: Put biodiversity at risk,» Lockwood et al’s «Non-natives: Plusses of invasion ecology,» and Lerdau &Wickham’s «Non-natives: Four risk factors») and Science published one in its commentary section, Lambertini et al’s «Invasives: A major conservation threat» .

25The first reaction was authored by prominent invasion biologist Daniel Simberloff and his 141 signatories who begin «We the undersigned feel that in advocating a change in the environmental management of introduced species Davis et al assail two straw men». First, they assert «most conservation biologists and ecologist do not oppose non-native species per se». Second, «invasion biologists and managers do not ignore the benefits of introduced species». They state that Davis et al «downplay the severe impact of non-native species that may not manifest for decades after their introduction» and that «pronouncing a newly introduced species as harmless can lead to bad decisions about its management». The essay cites the eradication of 27 invasive species in the Galapagos Islands as evidence to the contrary that «harmful invasive species have been successfully kept in check by biological, chemical and mechanical means». They conclude with the pronouncement: «The public must be vigilant of introductions and continue to support the many successful management efforts» (all quotes p. 36).

26Opening with the statement «bias against non-native species is not xenophobic (Nature, 474, 153-154; 2011)—it has a sound scientific foundation,» Alyokhin’s, «Non-natives: put biodiversity at riskv contends that «the non-native status of a species is highly relevant to assessing its potential environmental and economic impacts» (p. 36). The author cites the introduction of placental mammals to Australia, as the case in point regarding the negative influence of the «invaders» on global biodiversity. Lockwood et al’s 124-word defense of invasion ecology, «Non-natives: plusses of invasion ecology» opens with the assertion that «Contrary to the implications of Mark Davis and colleagues…invasion ecology has given us valuable insight into the effects of new species on ecological function» and continues with the assertion that as early as 1986 the position among invasion ecologists has generally been «that only a very small fraction of non-native species harm their new ecosystems» (p. 36). Like Simberloff et al, they conclude with a direct appeal: «It is unfair to characterize any scientific discipline solely by past failures and to ignore its successes. Invasion ecology is making real progress with defining impact and characterizing risk. Let’s not throw up our hands in despair just yet» (p. 36).

27The final piece in the July issue, Lerdau and Wichams, «Non-natives: four risk factors» makes an argument for efficiency stating «Mark Davis et al. set an unrealistically high bar for those making management decisions about exotic species…Control is often easier, cheaper and more effective soon after detection» (p. 36). Given the problem that research on ecosystem impact «can take years,» the authors propose four guidelines for easily identifying disruptive invaders: high reproductive rates, dispersal ability, food source similarities, and lack of predators and pathogens. They conclude with the example of the red turpentine beetle in North America versus China.

28Lambertini et al’s Science commentary, «Invasives: A major conservation threat» is the most critical of Davis et al. The authors, «leaders of conservation organizations with missions to protect biodiversity,» assert that Davis et al’s proposal to downsize «the struggle against invasives» and the recent calls «upon the conservation community to embrace invasive species»incorrectly imply «that the concern with invasive species derives from the unreasonable desire to maintain pristine ecosystems and exclude all alien species» (p. 404). They assert that conservationists recognize the dynamic nature of species distributions, and the important distinction between alien and invasive species. The authors «believe that the endorsement of invading species—although potentially stimulating from an academic perspective—risks trivializing the global action that is need to address one of the most severe and fastest growing threats to biological diversity» (p. 405) and go on to cite the successes of conservation organizations and practitioners in combating invasive species, promoting biosecurity, supporting eradications, recovering ecosystems, preventing extinctions, protecting biodiversity, addressing threats to human communities including food and water access, disease and economic damage. They assert that their organizations are on the «frontline»of international initiatives to «prevent, control and eradicate the most harmful invasive species» and as such «encourage countries and communities to support and contribute this effort». Speaking directly to academics, they conclude, «Now more than ever, academics should be supporting action against invasive species, identifying tomorrow’s most damaging invaders to enhance prevention, and working actively to develop innovative tools to control, eradicate or mitigate the impacts of the most harmful invaders» (p. 405).

29The summer of dispute ended with Marque’s, «Invasives: Sea of data to come» and Moore’s «Invasives: Classify with care» in the August 19 issue of Science. Marque’s short piece asserts that «alarmingly» too little is known about the natural history of his research area (marine invertebrates) to correctly label species (native/non-native/invasive) and to thus take appropriate actions. The author suggests that lack of knowledge about natural history of species dispersal has led in some cases to the misinterpretation of species as «potentially hazardous bioinvaders when, in fact they are natural distributions» (p. 936). Moore’s concluding piece offers a reflection on the summer of debate stating «in the ensuing tumult, [Davis et als’] ideas have become obfuscated by semantics». He reminds readers that Davis and his colleagues never used the term «invasive» and that their comments reflected the idea shared by most managers and decision makers that «species management decisions should be based on goals for the area in question, not solely on the native or non-native classification of the species» (p. 936). The most noteworthy feature of Moore’s response is its attention to the importance of language, whether it be «the many terms to describe non-native species, the degree to which they thrive in their new environment, and their impacts on ecosystems», the «misleading» descriptions of Davis et al’s essay or the need to «keep the arguments clear» (p. 936).

30While it does not directly engage in this specific debate, it is worth noting that Science’s August 5 book review blog «Books et al« published a 2-page review («Mind your language») of Brendon Larson’s recently published Metaphors for sustainability, a book that explores how language functions in scientific inquiry and offers a detailed analysis of four «feedback metaphors» in the sustainability sciences, one of which is «invasional meltdown». The thorough and positive review concludes with the statement « [the book] seems an essential read for practicing scientists, editors and reviewers, students and teachers, policy-makers and funders, and the informed public. While words alone will not save the world, the art of conversation may lead to better conservation» (Golubiewski, 2011, p. 701) and is followed by Larson’s own words: «Part of what a poet does is come up with novel language that reveals something that was previously unnoticed. Such metaphors can help enliven environmental science, especially when they inspire love for local places that people care about» (2011, p. 228).

Controversial commentary: Unleashing the «dogs of rhetoric»

31Notwithstanding Alyokhin’s outright defense of «bias against non-native species»as having «sound scientific foundation» (p. 36) and Moore’s lament that «ideas have become obfuscated by semantics» (p. 936), reactions to Davis et al’s comment sidestepped their provocation on language, focusing instead on three themes: (1) wholesale rejection of claims of bias without supporting evidence (Lockwood et al & Simberloff et al), (2) anecdotal evidence of the successes and values of mainstream eradication and management efforts (Lockwood et al, Lambertini et al, Simberloff et al) and (3) risk and efficiency-based appeals for the continued support of conservation pursuits (Simberloff et al, Lambertini et al, Lerdau and Wickham). While Marques’ «Invasives: A sea of data to come» is an appeal for continued research, the author’s advancement of «better understanding of the natural history of marine invertebrates» (p. 936) and careful use of terms to describe species (e.g. using «organisms»and «species» as opposed to «invasives,» «aliens,» «colonizers» and «non-natives»), is in set stark contrast to the crisis-oriented, militant and imprecise language that characterizes much of the commentary.

32The problematic language surrounding invasive species was first brought to my attention in 2009 when I joined colleagues for a habit restoration project sponsored by the Environmental Sciences program at my university in southern Switzerland. The central objective of the «clean up» was the removal of an «invasive» windmill palm that had taken root in a local nature reserve. The participating students took the task seriously, perhaps too seriously. I was struck by the symbolic and physical fervor with which volunteers removed the palms and (perhaps strangely) felt a sort of empathy for the baby palms whose only crime was trespassing beyond the walled gardens their ancestors were brought here to beautify in the 19th century. While I understood the threat of the palm to the «local» flora and fauna, I was taken aback by the fury that joined the scythe. In retrospect, I should not have been so surprised; for what other action might the language of «invasion» inspire?

33The editorial decision in Nature and Science to publish, indeed facilitate, this internal dispute on a «popular» forum—first by inviting Davis et al’s original comment and then printing seven reactions over the next two months—suggests awareness on their part of the contemporary salience of the dispute. Indeed, given its colonial heritage, postcolonial origins and rapid growth in the context of early 21^st century environmental and social justice issues, the topic of invasive species was ripe for the debating. And though the debate has been a part of a wider interest in language in the sciences, it also revealed enduring misconceptions about language. According to ecologist Brendon Larson (2011), the enduring and pervasive impression of science as purely empirical and neutral has lent to an understanding—both by scientists and publics—of language as instrumental. What is more, «Scientists are not accustomed to being questioned about their language. Their facts—maybe. Their words—no. Many scientists don’t think it matters, stating it’s just a matter of semantics» (Golubiewski, 2011, p. 700). The contributions in this dispute overwhelmingly exhibited these attitudes toward language. One critical question then is, why and through what mechanisms do such misconceptions persist?

34One explanation may be the forum in which the dispute took place. Letters, correspondence and comments constitute an important and unique genre of scientific argument and exchange and are regular features of both Nature (Britain) and Science (United States). In addition to their primary mission to publish peer-reviewed original research for an international audience, both journals have non-peer reviewed sections dedicated to news, media, reviews, commentary and analysis. All eight texts in this dispute were published within the «commentary» sections of each journal, starting in June with Davis et als «comment» in Nature proceeding in July with four «correspondences» in Nature and one «letter» in Science and concluding in August with two «letters» in Science. According to the journals’ guidelines for authors, «commentary» sections are generally commission-only and designed to provide a space to discuss issues of general interest in an accessible and appealing style. According to Nature, «comment pieces can be writerly historical narratives or conceptual or philosophical arguments of pressing contemporary relevance, told with authority, colour, vivacity and personal voice. These attempt to bring an original perspective before the widest readership, through erudite reasoning and telling examples» (https://www.nature.com/​nature/​for-authors/​other-subs). Commentary pieces alternately «are generally agenda-setting, authoritative, informed and often provocative expert pieces calling for action on topical issues pertaining to scientific research and its political, ethical and social ramifications. They road-map a proposed solution in detail; they do not simply snapshot a problem» (https://www.nature.com/​nature/​for-authors/​other-subs). According to Science, letters «discuss material published in Science in the last 3 months or issues of general interest» (https://www.sciencemag.org/​authors/​science-information-authors).

Decolonizing the Anthropocene: «We are here because you were there»

36One of the first features of this dispute that caught my attention was the illustration around which the first four responses were set—a sketch depicting four humans, a kangaroo and an alligator taking a «citizenship test». The satirical image underscores the informality of the forum but it also signals editorial recognition of Davis et al’s central provocation: «Classifying biota according to their adherence to cultural standards of belonging, citizen, fair play, and morality does not advance our understanding of ecology» (p. 153). Though the debate was not cast, nor perhaps conceived, in colonial terms, Davis et al’s suggestion that the field «ditch this preoccupation with the native-alien dichotomy» (p. 153) is in step with the emergent global reckoning with the enduring legacies of colonialism in our institutions, systems, monuments, stories and symbols. This illustration draws attention to the absurdity of applying human standards of «belonging, citizen, fair play, and morality» to non-humans but it may also encourage deeper reflection about the cultural and historical context in which such standards emerged. Regrettably, only Marques’ «Invasives: A sea of data to come» highlights the importance of history in the classification and management of species. In her poignant reflection on this debate, paleoecologist Jacqueline Gill wonders «what a deeper time perspective could offer invasive ecology» (2011, n.p.).

37While contemporary critics of invasion ecology astutely flag the problematic implications of militant and nativist rhetoric on management practices and public perception, they have yet to appropriately situate the field (and its biases and language) in its historical context. Just as early natural science was indelibly marked by colonialism, so too has invasion ecology been shaped by its development alongside decolonial processes and preoccupations. And as an outgrowth of the mid-nineteenth century conservation movement, invasion ecology bares the marks of both colonial and decolonial attitudes. According to Adams and Mulligan, while conservationism reflected a «social reaction against technology, industrialization and growth-oriented development» it was nevertheless «deeply imbued with the European Enlightenment values that drove global colonial development» and «reflected the ideologies of nature that grew out of utilitarian and reductionist ‘natural sciences’» (2004, p. 7). Conservation parks and protected areas were first established in the colonial «peripheries» not only because the environmental degradation caused by colonial exploitation was more visible there but also because colonists imagined colonies as «a golden opportunity for retrieving some of the knowledge of nature man had had in the Garden of Eden» (Mastnak, Elvachar and Boellstorff, 2014, p. 365). As these «Gardens of Eden» increasingly bore the mark of colonial exploitation, conservation sites became colonial « nativity scenes». To this day, conservation practices, including invasion management, remain unreflexively embedded in such conceptions and valorisations of «nativity». As journalist Sonia Shah (2020) notes, present language around migratory and non-native species obscures our own roles (past and present) in creating the opportunities for non-native species to spread outside their range. Perhaps it is time ecologists recognize and reconcile Ambalavaner Sivanandan’s poignant aphorism, vwe are here because you are there». And just as in human migration, while we cannot practically or ethically undo the past, we do not have to reproduce it. The charge of the Anthropocene then is to thoughtfully assess and ethically redress the abrupt displacement and destruction wrought by colonial processes and pursuits.

Conclusion

38As Kuhn suggests, periods of crises in a disciplinary matrix involve recourse to philosophy and fundamentals. While Davis et al’s provocation attempted to steer the dispute to level of fundamentals, most of the early reactions side-skirted this deeper provocation altogether, evoking instead familiar mantras about the successes and importance of invasive management and the risks of inaction. In addition to avoiding deeper discussions about language, texts in this dispute displayed the enduring conception in science of language as mechanistic, trivial and/or derogatory. And while the editorial decision to air this debate in a public forum acknowledged the contemporary salience of the issue, it may have also reinforced problematic distinctions between the rhetoric of public science and the rhetoric of «real» science.

39In addition to highlighting persistent misunderstandings of the role of language in knowledge production, this analysis has attempted to take this discussion deeper, revealing the enduring legacies of colonialism in our scientific language and constructs and, I hope, demonstrating the value of rhetorical approaches to the study of scientific discourses. As postcolonial theorist Elleke Boehmer asserts, «decolonization demanded—and still demands—symbolic overhaul, a reshaping of dominant meanings» (2005, p. 3). Invasion ecology is one central site for symbolic overhaul. Equipped with a better understanding of the colonial roots of conservation ecology, communication scholars, invasion scientists, and the communities they serve, can both better understand this dispute and also devise rhetorical frameworks better suited to the project of decolonising and repairing our planet. As ecologist Brendon Larson suggests, «to make the shift to sustainability, we must overcome embedded faults in our socioecological systems. If the dominant discourse is unsustainable, we need to address it and select an ‘outlaw’ discourse» (Larson, 2011, p. 18-19).