A Rambunctious Book Review: Finding the middle ground in restoration ecology

Introduction

In an era of accelerating environmental uncertainty, Emma Marris has left her mark on the field of ecological restoration with her new, daring perspectives. Often met with recoil by traditional preservationists, her book Rambunctious Garden has pushed the discussion forward by asking the field’s toughest questions and trying to answer them without adhering to conventional paradigms. 

Overall Framing

One reason many ecologists may react negatively to Marris’ book is the understatement of invasive species. Whereas invasives are usually discussed at length for their ecological downsides, Rambunctious Garden plays devil’s advocate by arguing the contrary. Although I do not necessarily disagree with many of the points she develops, I too was nevertheless taken aback by her unrestrained support for nonnative proliferation and novel ecosystems. Realistically Marris does recognize the potential downsides of nonnative species, however since the book greatly avoids presenting those concerns it gives the impression that she is pro-invasive at the detriment to other species. This selective framing can be found in chapter 6: It is initially established that nonnatives can have negative ecological consequences, but when discussing individual nonnative species, Marris doesn’t reiterate the downsides. I assume she restricts her focus to emphasize the potential utility of nonnatives, however without proper qualification the discussion comes off as one-sided. For a specific example, on page 119, Marris frames Phragmites management as ecologists’ ‘chasing their own tails,’ but fails to explain the reason why “Phrag” is so ecologically destructive in the first place. Rather, she ends the paragraph with a joke about job security, undercutting the restorer’s authority on the subject. To more fairly represent the issue of invasive management and mitigate the community’s objections to her argument, I recommend more graciously emphasizing the negatives along with the positives. Yes, nonnative plants could potentially be good— but there’s no reason to frame existing invasive management as useless without properly discussing the species’ site-specific behavior.

Other examples exist of this selective framing, from which criticism of Marris lies not on the point she develops but rather her disregard of important qualifiers. In chapter 3, Marris argues against strict adherence to historic references since ecosystems are constantly changing, thus admitting some degree of nonnative introduction. As evidence for this claim’s validity, she discusses nonnative proxies, which are not “pristine” in their historical accuracy but are functionally similar (pages 68-69). This argument succeeds in destigmatizing nonnatives but again fails to give nuance to the relevant differences between different nonnative species that make them invasive within certain environments. To mediate this blind spot, it would be useful to explicitly state that nonnatives are good insofar as they serve functional roles, rather than the open-ended pro-nonnative stance implicit within the text. 

Historic Reference Points

Mirroring the above point, Marris’ discussion of baselines in chapter 3 functions more to criticize the wilderness concept than to generate new discussion on how reference points may be used as a tool. Based on the fact that Indigenous humans greatly changed the landscapes in which they lived, she argues that pre-colonial baselines are human-derived and thus not as pristine of a condition as some would like to believe. This point reiterates Cronon’s criticism of human-nature duality, moving restoration away from wilderness idealization, but this reflects very little on how reference points are practically used as a means to promote systems functioning. Marris mainly interprets baselines and historical references as a remnant of the wilderness ideal, and dismantling that ideology logically leads to disregarding baselines. But from my knowledge of ecology, reference states still have immense utility outside of that stifling ideological framework. Baselines need not be interpreted as idealizing a perfect replication of historic conditions— in fact, Marris does care for historic references as revealed by her positive discussion of Pleistocene rewilding, yet the absolute link she envisions between baselines and the wilderness concept prevents her from admitting their ability to inform imperfect inspirations. Baselines derived from historic reference points can be used as a more general guide for how to promote certain ecosystem functions, rather than for species makeup directly. Using this definition of baselines, restorers can incorporate nonnative species and geographical changes while still being grounded in local references. 

Non-Native vs. Invasive

Above all, I would like to call attention to the terms exotic (nonnative) and invasive. Marris seems to use these words interchangeably, greatly reflecting the cultural emphasis on natives as inherently good, therefore making all nonnatives bad and invasive or exotic. 11 years after this book was published, however, I was taught a quite different perspective, possibly a result of the book’s impact on the field of ecology. Laura Dee of University Colorado Boulder taught me that non-nativeness and invasiveness are separate concepts, where not all nonnative plants act invasively, and native plants can act invasively (under the wrong conditions). With this distinction, the book’s arguments become much more straightforward. Whereas Marris argued for the acceptance of “invasives” by criticizing the wilderness concept, it would have been much more agreeable if she specified non-invasive nonnatives.

At some points, however, Marris does actually refer to invasive behavior positively. For example, fast establishment of nonnative plants can be interpreted as ‘bad’ if it hinders functionally-significant plants, however it could also be considered ‘good’ if it helps prevent erosion or supplies shading for other species. In this, Marris advocates not just for the acceptance of mere nonnatives, but for invasive nonnatives. 

With the book’s current wording, the arguments in favor of 1. accepting nonnative species and 2. accepting invasive behavior are not properly distinguished and may be confused. Although Marris advocates for both under the umbrella of “exotic acceptance,” they are actually quite different as people can readily accept some nonnative species while still denouncing the invasive behavior of others. I believe this to be a much more moderate conclusion between traditional ecology and Marris’ radical acceptance of invasives.

Complex Interactions

Unlike Marris’ liberal inclusion of nonnative invasives, I still give a premium to functional roles/niches within ecosystems, posited to have coevolved between native species. In this, I think proxies to “original” species may be good enough to fulfill some roles, but I’m hesitant to say that nonnatives in general can do so in a reliable manner. The book gives examples of how nonnatives can provide individual functions like food or shade, but such surface-level interaction may not be a sufficient replacement for coevolved complexity. Marris argues that adaptive capacities of ecological systems can make up for this difference, however the metrics she cites fail to adequately convince me:

In systems ecology, biodiversity and a species’ presence do not have direct value— they’re reductive shorthands for referencing general ecological integrity. We care about biodiversity because it supports resilient, functional ecosystems, being just an indicator of ecological health rather than a final measure of it. Because of this, simple reference to biodiversity and extinction rates can be misleading as they doesn’t show the full picture. For example, the Shannon Diversity Index over-values species richness: a site may be majority dominated by a single plant species, but as long as other species exist in small quantities along the margins, then the metric will be inflated. This situation represents a near monoculture, but the reported total number of species distracts from the unnatural distribution. In this vein, Marris purports that adding invasive species is good as it increases the total number of species present, but her data lacks specification as to the nature of biodiversity. In order to prove that invasive nonnatives can coexist with native populations over time, I would like to see more research and details than have been so far presented.

Restoration Goals

The strongest and widest-reaching argument Marris presents against traditional restoration is its infeasibility. Although many people would like to return to ideal wilderness, the truth is that the world has changed and we lack the technical ability to restore historic conditions. Considering the time sensitivity of ecological concerns and a lack of project funding, it’s better to use the money wisely than be distracted by ideals, however there is a real danger in settling for less. 

One fear is that a lack of defined baselines will dilute the concept of nature so as to compromise overall structure and function. A big strength of using historic references is that they preserve the established complex interactions developed over time, whereas novel ecosystems require reestablishment of niches. In this, a stricter definition of “natural” systems could be useful as imperceptible components are not accounted for in constructed environments, leading to unforeseen consequences when natural physiognomy is altered. Therefore presenting idealized restoration goals, though potentially unrealistic, functionally serves as a precaution. Expanded human control over nature is a slippery slope that may lead to further excused degradation, a sentiment echoed by Schwartz on page 96. “Without a baseline we have no target. Without a target, every kind of management, including those that result in lost native species, is arguably a success.” This same precautionary argument can be applied to how we choose to value ecosystems. Compared to an ecocentric or biocentric ethic, anthropocentric ecosystem services run the risk of lowering ecological standards via their reductionist approach. Rather than confiding in the security of the past, however, Marris leans into novel ecologies as supporting ecosystem services. As discussed, this is potentially dangerous, but she avoids this criticism by referencing ecological adaptiveness. One’s opinion on novel ecosystems may thus depend on their perception of resiliency and willingness to risk unknown ecological intricacies.

Conclusion

Perhaps I am just too conservative to accept her “eco-industrial” vision, but whether one fully agrees with Marris or not is less important than the discussion this book generates. In advancing an important set of arguments, Rambunctious Garden ought to be given thoughtful consideration as well as analysis and critique. Many of the core arguments about wilderness and nativeness hold up to scrutiny, but some of the more controversial opinions require further debate. I personally would recommend Rambunctious Garden to people within the field of ecology in order to challenge the standards of existing management projects, however I caution full promotion of the book because some of its arguments are dissatisfactory. Given that the book was published over 12 years ago, I am curious how the field of ecology has since tested her hypotheses. What I do know though, is that Phragmites has yet to become my friend.