Digital Project

Unseen Majority

“What happens if we don’t touch buckthorn for a hundred years?” Poet Jared Stanley speaks with microbial ecologist Chelsea Carey about assisted migration, invasive flora, plants as active subjects, and the complex relationship between microorganisms and their environment. Stanley's “Oaths of the Blossoms,” an essay and artwork that considers how the poetry of notary publics might let flowers speak for themselves, was recently published by Triple Canopy.

Jared StanleyWe were talking the other day about how we’re not only presently losing habitat, but habitat itself is moving (north, most often). This sometimes requires local-level improvisation at odds with the standard principles of the field of ecology. You mentioned “assisted migration,” in which conservation scientists help endemic species move into new habitats that will, if climate predictions are correct, be suitable habitats for those species. But some are resistant to this practice.

Chelsea CareyApplied ecologists—and restoration ecologists in particular—have always had to address difficult ethical questions. Decades ago, when the non-scientific community (and some in the scientific community) pushed back against projects removing invasive plants, we had to really consider why we were attempting to eradicate these species and how we could justify our actions. Attempts to answer these questions were, and continue to be, confused by debate around what to restore to.

When discussing a concept as young and radical as assisted migration—just as invasive species eradication was thirty years ago—a sense of doubt surfaces. Will assisted migration result in invasion—in which non-native species are introduced to an ecosystem, intentionally or by accident—which can reduce biodiversity and alter ecosystem functioning (e.g., soil water availability)? And how do we know what the right thing to do is? No amount of data can ensure that we choose correctly—assuming that there is only one correct way. How ecosystems change as a result of global warming, and how we subsequently respond as ecologists and land managers, depends on a whole suite of interacting abiotic (non-living) and biotic (living) variables. The complexity of these interactions has historically limited our ability to generalize across space and time; as a result, no single course of action can be applied to every case. It would be easy to argue that the only overarching rule (or law) in ecology is: It depends.

StanleyAre there people who think that invasion is already such a pervasive phenomenon that the very idea that invasion wouldn’t occur is a fantasy?

CareyAs an invasion ecologist one cringes when one hears that, but you’re right. A hypothetical land manager might be encouraged to facilitate migration of a plant species if the site is on the edge of the species’ expanding climate range. However, in another scenario not located on the edge of this range, the land manager may be fine trying to restore in a more traditional way. In either case, it is unlikely that the land manager would explicitly be told they’ve been doing it wrong; instead, they will be encouraged to alter the way they have been practicing restoration/conservation by adopting practices they may not be particularly comfortable with (e.g., not removing invasive plants within an area because they help stabilize stream banks and minimize erosion; facilitating assisted migration of native plants).

While there are many areas where assisted migration is successful, there are at least a few difficulties. Soil is a prime example: There is some evidence that invasive plants influence the soil in ways that can facilitate their persistence. Many studies have looked at methods to manipulate soil after the removal of invasives in order to increase restoration success; however, there are very few examples where these approaches have been applied in actual restoration projects. This has to do with the feasibility of measuring and manipulating soil properties (especially microbial/biotic) on a large scale with a limited budget. If and when more funding is allocated toward restoration, and soil measurement/manipulation techniques decrease in cost and increase in accessibility, we might see these techniques applied more frequently on larger scales. However, even with this advance, site-specific knowledge will often be required in order to successfully conserve or restore areas since, as is always the case, the effects of [insert any anthropogenic change here]—and the response entailed—will depend.

I worked on a project in Chicago called One Hundred Sites for One Hundred Years. One objective of this project is to observe systems that were invaded by Rhamnus cathartica, or European buckthorn. The plant is now the most prevalent woody species in all of the Chicago region, so it’s a massive management concern for most ecologists. Over a hundred years, we hope to monitor what happens at a variety of sites: places where the forest preserves are managing in various ways for buckthorn, and places that are not going to be touched at all. This project allows us to ask, “You know what—what happens if we don’t touch buckthorn for a hundred years? Is it just gonna go away on its own? Are we spending all this effort and money to control it when it’ll just take care of itself?”

StanleyI’m fascinated by your work on the interactions between plants and their soils at a scale, the microbiome, that is very hard to see. I wondered if you could talk a bit about how standards and practices in your work are acted upon and changed by global climate change?

CareyI study microbial communities by asking questions like: Who is there (in the soil, in the air)? What are they doing (transforming nitrogen, helping plants, producing methane)? How are the answers to these two questions altered by climate and other environmental changes (do community membership and activity change as climate and other environmental parameters change)? As a microbial ecologist, I am joining the effort to simply capture the diversity and functioning of this “unseen majority,” while at the same time trying to understand how these microbial drivers (of nutrient cycling, trace gas emissions, and plant composition) respond and offer feedback to climate and other global changes. In contrast to plant ecologists, we have very few tools to manage and manipulate microbial communities in the field; those that exist have been limited to small-scale restoration efforts and agriculture. In this way, what I do and how my work is affected by climate change have not advanced beyond trying to capture, at a fundamental level, the complex relationship between microorganisms and their environment. I should note, however, that there is a growing effort to include microbial communities in models of climate change, and to create more effective and cheaper ways to manipulate soil microbial communities during restoration and for biocontrol purposes (use as natural enemies to manage invasive populations).

In the broadest sense, our standards haven’t changed because methods of scientific inquiry are still the same. Ecologists have always been interested in capturing temporal and spatial patterns of interactions between organisms and the environment, and in determining what drives these patterns. These are still the fundamental questions at the heart of ecology. However, new questions and new experimental designs are certainly developed in order to help us understand and contend with global climate change. In fact, most research programs are linked either directly or indirectly to climate or other anthropogenic environmental changes (e.g., plant invasion, nitrogen deposition, land-use change). This is a shift that has developed over the past several decades: Many researchers now explicitly couch their questions in the context of anthropogenic change. Sometimes these questions are crafted in order to get funding, but mostly the development of specific research questions is driven by a recognition that there is a need to understand ecological interactions in a rapidly changing world. For instance, one question I am interested in exploring is: How do adaptations to local environmental parameters confer resistance and resilience in soil microbial communities? This is a basic ecological question, but the motivation for it is really a need to understand why some landscapes (and their microbial communities) are more vulnerable to climate change than others.

StanleyIn “Oaths of the Blossoms,” I’m trying to play with the notion that plants, specifically wildflowers, can be active subjects, as opposed to passive objects. Do practitioners of assisted migration consider plants objects to be moved around at will, as the ecosystem changes? Is there any sense that plants, part of the web of an ecosystem, are subjects and therefore possess certain, or even special, rights?

CareyThis is a really hard but great question. Yes, I believe that plants are active subjects insomuch as they interact with their environment (individual-level) and evolve (population-level). It is precisely because they are active subjects that we think of them as passive objects for assisted migration. In other words, because plants are active subjects, each species and even individual has different genetic and functional capabilities that allow it to survive in this or that environment. These differences, along with an inherent ability to adapt—or, in the case of rapid climate change, not adapt—to changing conditions, lay the foundation for humans to use plants as passive objects within and outside the context of assisted migration. Outside of assisted migration, for instance, plants are exploited as passive providers of medicine.

But here is a further question: Do we consider plants or any other organism to have a special right to exist? Well, to start, I’m not certain humans consider other humans to have the right to exist. What is the right to exist and where does it come from? Do we have the ultimate say? With that said, it seems that humans consider plants to have less right to exist than their animal counterparts. This, I would imagine, is probably because we identify less with plants than with animals, particularly vertebrates. We identify more with things that we are like than those that we are not like. Many humans have what is sometimes called “plant blindness,” meaning they don’t see or notice plants in their daily life, so how could they deem them to have rights? Ecologists may be more encompassing in their views, since they are in theory not plant blind and understand that plants are critical to life on Earth. But an appreciation for the importance of something does not necessarily lead to the view that something has a right to exist. In fact, it may be that understanding the importance or value of some nonhuman living entity minimizes or muddles our ability to believe that something—a plant, in this case—has an inherent right to exist. Since, pursuant to our assessment of its importance and value, there’s often an assumption that it exists to “serve,” for lack of a better term, humans.