The island marble butterfly (Euchloe ausonides insulanus), thought to be extinct throughout the 20th century until re-discovered on a single remote island in Puget Sound in 1998, has become the focus of a concerted protection effort to prevent its extinction. However, efforts to “restore” island marble habitat conflict with efforts to “restore” the prairie ecosystem where it lives, because of the butterfly’s use of a non-native “weedy” host plant. Through a case study of the island marble project, we examine the practice of ecological restoration as the enactment of particular norms that define which species are understood to belong in the place being restored. We contextualize this case study within ongoing debates over the value of “native” species, indicative of deep-seated uncertainties and anxieties about the role of human intervention to alter or manage landscapes and ecosystems, in the time commonly described as the “Anthropocene.” We interpret the question of “what plants and animals belong in a particular place?” as not a question of scientific truth, but a value-laden construct of environmental management in practice, and we argue for deeper reflexivity on the part of environmental scientists and managers about the social values that inform ecological restoration.
This case study examines the practice of ecological restoration, not as a straightforward process of “putting back” past environmental conditions, but as a complex, multi-faceted, and value-laden management practice. Readers will be able to: (1) compare versions of “restoration” that are premised on different values, (2) understand the distinction in restoration objectives between a commitment to historical fidelity, on the one hand, and an emphasis on conservation of an endangered species, on the other, (3) critically evaluate the concept of “nativeness” as a means of evaluating and prioritizing nonhuman belonging, (4) describe how the conventional wisdom of restoration is challenged when at-risk species require ecological conditions without a historical analog, and (5) distinguish competing approaches to restoration based on different underlying assumptions and values.
In 1998, a group of lepidopterists conducting a survey of insects on San Juan Island, WA were astonished to find a butterfly that had previously been believed to be extinct. The island marble butterfly (Euchloe ausonides insulanus), not observed since 1908, was now living on the prairie at American Camp in San Juan Island National Historical Park. Its survival had become dependent on the presence of appropriate host plants, including introduced species often described as “non-native” or “weedy.” Over the course of the next 20 years, land managers and scientists worked to develop a strategy to protect these butterflies, including restoring their habitat. The project’s importance was underscored by the determination made by the U.S. Fish and Wildlife Service that the island marble is warranted for listing as an endangered species . Throughout the same period, however, the National Park Service was simultaneously undertaking “an ambitious project to restore the prairie to a pristine state” . This effort, aimed at reestablishing the historic conditions and biotic assemblages of a rare and rapidly shrinking ecosystem type, the Puget Sound coastal prairie, prioritized the removal of introduced plant species and revegetation of the prairie with desirable native species .
In this case study, we argue that the case of the island marble butterfly rediscovery offers important insight into the human values at work in the practice of ecological restoration, with regard to what plants and animals belong in a given landscape or ecosystem. We take environmental management efforts on the San Juan Island prairie as demonstrative of two distinct versions of “restoration” in practice. The first, commonly described as prairie restoration, is largely premised on fidelity to historical ecological conditions, aimed at re-creating the biotic assemblages of an unaltered Puget Sound coastal prairie ecosystem. The second, butterfly habitat restoration, aims to create suitable living conditions for a single endangered species, the island marble butterfly, whose resource needs are dependent on anthropogenic activities including planting host plants.1
The distinction between these two modes of restoration reflects a longstanding debate over the usefulness and significance of the categories of “native” and “non-native” species, as normative assessments of what kinds of life belong, and should be protected or restored [4–6]. As Warren  points out, nativeness is fundamentally geographical—a species is either in or out of its place of origin. For many restorationists who have long relied on this distinction, the question of “what plants and animals belong in a particular place?” is readily answered by their status as either native or non-native. In contrast, we emphasize that belonging is not a fundamental quality of a plant or animal itself, but a particular, value-laden relationship between people and those plants or animals. Drawing on work in animal geography, we frame belonging as a relationship forged through the discourses and practices of conservation and restoration [8, 9].
Those discourses and practices are rapidly changing today, in the wake of the much-discussed diagnosis of the “Anthropocene,” a time when human effects on ecosystems are understood to extend to the farthest corners of the earth.2 The concomitant recognition that all ecological processes are part of integrated socioecological systems poses a significant challenge to conservationists’ usual emphasis on pristine natural ecosystems and processes. Of course, critiques of the idea of “nature” as a pristine state, unspoiled by human influence, have been well-rehearsed in academia since Cronon’s  critique of wilderness. Nonetheless, the idea of returning to a better environmental past lives on in what have been described as the “Edenic Sciences”  of conservation biology and restoration ecology. Debates over what William Adams describes as a “fracture zone in conservation” [13, p. 7] regarding the role of often-drastic human intervention to sustain so-called “natural” landscapes and ecosystems in the post-Natural world of the Anthropocene, have spilled from the halls of academia [14, 15] to the popular bookshelves [16–18].
The practice of restoration, as an intentional human intervention designed to repair previous human-induced environmental damage, stands precisely astride this fracture zone. Contrary to the stereotype of “restoration” as a literal return to past conditions, many restoration ecologists recognize that such a practice is neither necessarily desirable nor even possible.3 A narrowly defined commitment to historical fidelity in restoration, to the extent that it ever existed, has significantly given way to an emphasis on restoring the “historic trajectories”  and ecological processes  of ever-changing, non-equilibrium systems [23, 24]. This focus goes hand in hand with increasing interest in the so-called “novel” ecosystems and emergent, no-analog species assemblages of the Anthropocene [25, 26]. Despite this supposed turn toward “Restoration v2.0” , however, many restoration practitioners remain committed to a certain degree of fidelity to historical conditions, insofar as they continue to value native species over non-natives . In this context, the use of non-native plants (as in the case of the island marble butterfly) still marks a deviation from long-established norms in the practice of restoration.
By framing debates over native and non-native species as a question about the social norms that define nonhuman belonging, this case study examines how categories established by the natural sciences work to enact particular social values. We treat the practice of restoration as the construction of a “relational ecology of belonging”  in which categorizations, such as “native” and “non-native” species, serve to normalize either protecting or killing particular plants and animals. By drawing on the perspective of critical geography to emphasize the social construction of nature(s), we aim to offer a new lens through which to consider the implicit norms and values of restoration. The island marble case offers an opportunity to examine competing approaches to restoration based on different underlying social values, as well as to explore how those values are changing in the contemporary practice of restoration. While we do not aim to adjudicate what is the “right” nature to be restored, we argue that the deeper examination of these assumptions and values strengthens the theory and practice of restoration in and for the Anthropocene.
CASE EXAMINATION: THE ISLAND MARBLE BUTTERFLY
An unnamed butterfly was first collected and cataloged by the western scientists in the 19th century on Vancouver Island, BC, and adjacent islands . It was not seen again after 1908. The butterfly was considered extinct until the “shocking rediscovery”  made in 1998, which spurred a significant effort to learn more about the biology, lifecycle, and habitat of the “rediscovered” (and newly named) island marble butterfly, as well as to determine the size and geographic range of the population. Currently, the butterfly is found only on San Juan Island, with an estimated population of fewer than 500 individual organisms . It is one of the most restricted endemic butterflies in the continental United States .
Island marble survival is highly dependent on the presence of appropriate “host plants.” The butterflies lay their eggs on the flowers of the host plant, where they hatch into larvae (caterpillars). The larval stages of growth take place entirely on a single plant, where the caterpillar eats the gradually developing fruits and flowers. It then crawls off the host plant into surrounding vegetation and forms a pupa (chrysalis), where it spends the next 11 months of the year. The adult (butterfly), which emerges the following spring, lives for only about 10 days and spends this time locating mates, searching for host plants, and laying eggs to begin the cycle again. The butterflies are adapted to specific host plants, and their reproductive capacity is often limited at the larval stage by the absence of sufficient plant material.
One of the most frequently used hosts is field mustard (Brassica rapa) (Figure 1). A common non-native agricultural crop, field mustard springs up like a weed in sites with disturbed soil , including on the prairie at American Camp and along road corridors around San Juan Island.4 Field mustard was likely introduced by early settler farming in the region, perhaps as long ago as the mid-19th century, though no one knows precisely when the butterfly adopted it as a host plant. It was widespread across the prairie from the time the island marble was rediscovered there in 1998 through the early 2000s. By 2012, however, the plants were nearly absent from American Camp due to lack of soil disturbance, absence of seed, and grazing by deer, contributing to a sharp decline in the butterfly population.
The potential for (re)extinction of this newly (re)discovered species sparked alarm among conservationists who mobilized to protect it. They advocated aggressive steps for butterfly conservation, including growing butterfly larvae in captivity for re-release into the wild and fencing out deer from butterfly habitat areas. Notably, the Park also began planting field mustard at American Camp to enhance island marble habitat . These interventions were justified through an emphasis on the risk of extinction—for example, one local newspaper described the island marble butterfly as one of the “most imperiled animals in the world,” in “imminent danger of extinction” . The San Juan Preservation Trust  explains that “this is the only known place in the world where this tiny creature lives, and its future lays in our hands.” One scientist working on the project described this as an “endangered species mentality” that shifted her teams’ priorities by creating the imperative to take immediate steps for the animals’ protection. They felt compelled “to act, because we have to do something” to prevent extinction, she said, sometimes even in the absence of clearly defined knowledge about how best to do so . While the island marble butterfly had been understood to be at risk of extinction ever since its rediscovery in 1998, this mentality took on a new urgency after the 2012 crash in the field mustard population.
The imperative to protect the island marble butterfly, however, stood in conflict with a competing, preexisting set of environmental goals—a vision of ecological restoration premised on fidelity to historical conditions. The San Juan Island National Historical Park Management Plan, published in 2008, calls for using “prescribed burning, mechanical and/or chemical control of invasive plants, and planting of native grasses and forbs” to restore the grasslands at American Camp . Public outreach from the Park Service emphasized a baseline target for “returning the prairie to a pristine state” based on conditions before the arrival of European settlers . The National Park Service blog explained that the goal is to
“restore the prairie ecosystem by replacing exotic plant species with native vegetation. This effort benefits not only the plants and animals on the island, but will one day offer visitors a sweeping, unspoiled panorama of Puget Sound as it once existed, hundreds of years ago” 
The overlapping endeavors to restore the American Camp prairie to a pristine state and to restore the island marble butterfly population, while both articulated as “restoration,” in fact exemplify two competing environmental objectives. The field mustard plant stands at the intersection of these different approaches. In the eyes of a restoration effort characterized by a strong commitment to historical fidelity, mustard plants are understood to be non-native and therefore non-belonging, and potentially a risk for negative ecological effects such as outcompeting native prairie species. Indeed, field mustard removal continued to be a part of ongoing prairie restoration efforts even in the years immediately after island marble rediscovery.5 On the other hand, from the perspective of the restoration of the butterfly population, the mustard host plant can be reinterpreted as a critical habitat for the survival and reproduction of a rare, at-risk, and highly valued butterfly. Through these two approaches, the same plant can be constructed as either a threat to the ecosystem or a necessary component, and justifications can be made for killing it, allowing it to live, or propagating it across the landscape.
The official Conservation Agreement and Strategy for the Island Marble Butterfly noted these competing priorities, explaining that the rediscovery and prioritization of island marble posed “an enigmatic management challenge, whereby a species of high concern depends upon non-native species whose eradication in native-dominated habitats, if not a priority, would be otherwise desirable” , p. 5. This document, written in 2006, was emblematic of the initial effort to make the project conform to the norms of a more literal “restoration” to historical conditions. It emphasized the desire to find native host plants to be propagated “in the hope of reducing the island marble’s dependency upon non-native, invasive species of mustards” (p. 14).6 Despite that caveat, however, the agreement ultimately prioritized “the continued existence of the island marble butterfly at American Camp” over the “ability for restoration to pristine prairie conditions” (p. 15). Land management at American Camp followed suit: the island marble restoration effort underway since 2012 has included intentionally planting and cultivating the non-native mustards that are essential for butterfly reproduction.
The island marble butterfly rediscovery and protection effort are a useful case study for examining how scientists and policy-makers determine what plants and animals belong in a particular place or ecosystem (a key concern of restoration ecology and environmental conservation more broadly). The discourses surrounding the island marble project illuminate two significantly different conceptualizations of “restoration” at work, which we characterize as prairie restoration, on the one hand, and butterfly habitat restoration, on the other. The objectives of the first emphasize fidelity to historical ecological conditions, hence only native species are understood to belong in the American Camp ecosystem.7 From this perspective, restoration means a return to the “pristine state” of the prairie as it “once existed.” The second emphasizes the value of the endangered butterfly as one of the “most imperiled animals in the world.” Restoration in this context has come to mean the reproduction of a single endangered species, and by extension, its non-native host plants .
The distinction between these two versions of “restoration” reflects how the conventional wisdom of restoration, aimed at reproducing historical conditions, is challenged by the prioritization of an at-risk species whose reproduction is reliant on a non-native host plant and therefore requires ecological conditions without a historical analog. Those circumstances, though unusual, demonstrate an increasingly common conundrum in conservation practice, in which a species (here, field mustard) has a “dual status” of simultaneous belonging and non-belonging, creating “uncertainty for environmental management—should it be retained or removed?” , see also . The value of the plant as habitat for the butterfly seems to have largely won out, in this case, over the notion of belonging based on nativeness. The priority of the scientists working on the project today is to facilitate the successful recovery of the butterfly population, requiring the creation of an effective habitat for them, which includes propagating non-native plants across the landscape. The importance and value of the butterfly extend to encompass its ecological relations, necessitating a reconsideration of the value of the non-native field mustard plants as habitat.
The change in the terminology that is commonly used for field mustard—once commonly called an “alien species” or a “weed,” it is now typically described only as a “host plant”—exemplifies ecological management attitudes based on judging the belonging of this species not only by its origins but also by its ecological function [4, 43]. Such a shift is not unique to this case study: many restoration ecologists have begun to embrace the role that non-native species may play in restoration efforts [44, 45]. Active propagation of non-native host plants on the San Juan Island prairie could, therefore, be interpreted as evidence of shifting values in ecological restoration for the Anthropocene, akin to “Restoration v2.0” . Land managers at American Camp have deemphasized nativeness as an ecological priority, valuing the processes that produce (desirable forms of) life rather than aiming to reproduce a static set of past conditions, and recognizing that human-induced changes to the ecosystem are here to stay.
Importantly, though, this shift in thinking was made possible by the status of the butterfly as an extremely rare, at-risk species, whose rediscovery sparked the reevaluation of field mustard’s role in the ecosystem. We argue that the willingness of restorationists to actively propagate a non-native species cannot be understood without a simultaneous analysis of the “endangered species mentality,” self-diagnosed by a scientist working on the project. This mentality emphasizes the small size of the butterfly population and the risk factors it faces—including, especially, anthropogenic threats such as disturbances due to development or agriculture. The discursive emphasis on endangerment and extinction produces the island marble butterfly as a valued species worthy of special protection and justifies the tremendous effort undertaken to sustain it (“its future lays in our hands”). This mentality necessitated the new approach to restoration that would allow for the production of island marble habitat. Moreover, any appeal to historical conditions was made difficult in the context of a “rediscovered” species, thought to have been extinct for the better part of a century, whose historical ecological conditions and relations (e.g., host plants) can be only guessed. The move to “restore” a no-analog system was possible not only because of new models of ecological thinking but also because of the significant social value placed on this particular endangered species.8 Even with that emphasis, the shift to using a non-native plant was a challenge for restorationists, as evidenced by the intensive, but ultimately unsuccessful, effort to develop a restoration plan that would help the butterfly transition “back” to a native host plant.
This case study offers important lessons to other restoration practitioners dealing with non-native species, “novel” ecological systems, and other socio-ecological relations in the Anthropocene. While the different versions of “restoration” observed in the island marble case have conflicting goals, we argue that the tension between them is a productive one because it reveals the assumptions and values are implicit in each version. The question of which types of nonhuman life belong is not a scientific truth, but instead a social norm that reinforces and is reinforced by these underlying human values. In the context of an ongoing paradigm shift in the theory of restoration ecology (from “Edenic science” to “Restoration v2.0”), restoration practitioners find themselves grappling with competing norms about nonhuman belonging. Significantly, though, those norms are not commonly recognized as socially constructed, taking on apparent objectivity through scientific categories such as “native” and “non-native” species. Those categories still hold sway, for many practitioners, as the primary means of determining which species belong.
The case study of island marble rediscovery and restoration, while certainly demonstrative of a broader, ongoing shift in ecological thinking, also highlights significant resistance to that shift on the part of restoration practitioners, as they struggled to decide between competing ecological commitments and priorities. Even as the scientific literature in restoration ecology (and the popular literature on “post-wild” conservation) has moved away from a strong commitment to historical fidelity, on-the-ground practitioners, in this case, were initially quite resistant to do so. Restorationists at American Camp placed a strong discursive emphasis on “pristine” nature, even when faced with compelling reasons that ultimately led them to embrace a non-native species.
The distinction between “prairie” restoration, on the one hand, and “habitat” restoration, on the other, should not be misinterpreted as simply an older version of restoration being replaced by a newer one. Instead, restorationists at American Camp have been engaged in an active process of re-evaluating the categories and value judgments that underlie their actions. Understanding restoration as encompassing a wide variety of practices based on multiple values (such as a commitment to historical fidelity or to protect endangered species) serves to rebut critiques of restoration as hopelessly or nostalgically aimed at re-creating a lost past. Moreover, the analysis of these competing versions makes clear that restoration is not only a technical or scientific practice but also one that enacts particular social norms and values. This view, far from taking a relativist stance on the politics of restoration, instead opens up space for critical reflection on the political and ethical role of the restorationist, and the kind of human-nature relations that are created through the act of restoration.
We argue that the island marble case demonstrates that restoration should be interpreted and understood not only as a singular practice with self-evident, objective, scientific goals (such as removing non-native species in general or creating conditions “as they once existed”) but also as a contingent, site-specific, and value-laden art of constructing desirable environmental futures. As we have shown, practices labeled “restoration” may draw on different environmental values, such as the competing ideas of belonging that are enacted in the island marble case. Our goal is not to evaluate these approaches, but instead to argue that recognition (and subsequent debate) over the underlying environmental values is precisely what is needed—and cannot be automatically resolved by appeals to conventional norms—in the practice of restoration. A critical examination of the categories, such as “native” species, by which we evaluate nonhuman belonging is a conceptual challenge for practitioners of restoration and will require ongoing re-examination from project to project. Yet restoration itself, conceptualized as the active examination of human-ecological relations, rather than the simple putting-back of historical conditions, is and will be a critical practice for environmental management in the Anthropocene.
CASE STUDY QUESTIONS
How is a practice of restoration that is premised on historical fidelity different from the restoration that focuses on the conservation of an endangered species?
How is the conventional wisdom of restoration challenged in the case of the island marble butterfly?
What are the differences between “prairie” restoration and “habitat” restoration in the case of the island marble butterfly? What restoration objectives are misaligned in these two approaches?
Can you think of other case studies, or contexts, in which prioritizing either historical fidelity or endangered species conservation might lead to different objectives?
How is the concept of “nativeness” defined?
What is the relationship between “nativeness” and “belonging”?
Do you think the use of non-native species in restoration is justified in the case of the island marble butterfly, or more generally when needed to protect endangered species?
What factors should be considered when making decisions about the use of non-native species in restoration; what trade-offs might be involved?
What is the role of human values in the processes of ecological restoration and conservation?
Do you think that restoration as a technical, scientific process can be separated from social or cultural values regarding plants, animals, and ecosystems?
Do you think there are differences between how scientists and professionals understand the practice of ecological restoration, and how the general public does?
RA conceptualized the argument and drafted the initial manuscript. AL provided technical data on the island marble butterfly and developed pedagogical aspects of the case. Both authors contributed to revising the final manuscript.
AL would like to thank Dr. Julie Combs for her valuable and constructive suggestions during the development of this research and assistance with data collection. RA would like to thank Christine Biermann, Sarah Elwood, Victoria Lawson, Caitlin Alcorn, Elizabeth Shoffner, Yolanda Valencia, and Maggie Wilson for their constructive feedback on earlier versions of this paper.
AL wishes to acknowledge the financial assistance provided by the National Park Service and US Fish and Wildlife Service. RA’s research was supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1256082. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
The authors have declared that no competing interests exist.
DATA ACCESSIBILITY STATEMENT
Both of these types fall within the broader field typically described as “ecological restoration.” Since our goal is to unpack the various meanings implicit in “restoration,” we use this term without the modifier throughout this paper.
We use the term “Anthropocene” not as the name of a formal geological epoch (for which it has been proposed, but not formally adopted), but to signal the growing ecological uncertainty and anxiety about the proper role of human intervention into ecological systems, in the wake of appeals to pristine nature. That is, we take the idea of the Anthropocene to suggest an ontological shift rather than a strictly scientific question .
The butterfly has been observed to use three different species of host plants, one of which is a native species. Early efforts at island marble conservation and preservation, during the period of approximately 1998–2012, emphasized the protection of existing populations of all host plants. In this paper, we focus on the non-native field mustard precisely because it has been embraced by the habitat enhancement effort since 2012.
The phrase “prairie restoration” has typically meant the re-establishment of the community of species commonly and historically found on Puget Sound prairies—and thus, an implicit or explicit commitment to native species. Of course, this is not the only possible definition. Contemporary practice at SJINHP seems to be moving toward a redefinition of “prairie restoration” that represents a compromise between the different priorities outlined here, including the establishment of field mustard for island marble habitat as part of the suite of desirable species.
Endangered species conservation is itself often a preservationist impulse, aimed at maintaining extant biodiversity as a snapshot in time rather than emphasizing ecological processes (which could include, for instance, extinction). In this way, while the newer mode we describe as “habitat restoration” values field mustard for its ecological function as butterfly habitat, the restoration project as a whole can still be understood as having a commitment to historical fidelity, with the aim of reproducing a historical species assemblage (a prairie ecosystem that includes the butterfly), albeit modified by the presence of non-native species.