Since my last post on our Hemlock Hospice installation and exhibition, we had a very successful opening event (October 7) that brought more than 150 people to Harvard Forest, many of who had never been here before; the 18+ outdoor sculptures have successfull weathered torrential rains, howling winds, and the season’s first three snowfalls; and, in the past 6 weeks, over 400 more visitors have signed into the log book, leaving comments there and on ribbons tied to the Exchange Tree.
Lead artist and designer David Buckley Borden and I have given many tours of the exhibition to groups both large and small, and to visiting journalists who have written or are writing pieces about it for a range of audiences. All of these individuals have asked interesting and provocative questions that have spurred us to continue to think ever more deeply about the pieces and their broader meaning and context.
In this essay, I reflect on “invasive species”, how we conceptualize and contextualize them, and how we relate to them. My focus here is on the hemlock woolly adelgid (“HWA”), which is the non-native insect that is killing eastern hemlock throughout the range of this magnificent, late successional tree, but the ideas are, I hope, applicable to other invasive species.
The seventh piece on the Hemlock Hospice trail is the HWA Tent (illustrated below). The formative idea for this piece came during a discussion with our summer student intern, Salua Rivero, that focused on how the adelgid has found and makes its (new) home in North American hemlock forests. We wanted to articulate the idea that the adelgid is just like any other animal. It needs a place to live, to eat, and to reproduce, and our hemlock forests can be seen as temporary housing and a food source for these short-lived insects. The HWA Tent illustrates these ideas. The tent is green, and like a hemlock needle, it has two white stripes underneath. Tents are not, or should not be in 21st century North America, permanent housing. The state “patches” silkscreened onto the canvas represent all the US states from which the adelgid is known to occur (HWA also is established in British Columbia, Canada [since the 1920s], and has been recorded in Ontario [2011 and 2013; eradication thought likely] and Nova Scotia ); their seemingly haphazard arrangement is analogous to how a backpacker might array patches of visited locations on her jacket, backpack, or tent.
In reminding ourselves and visitors to Hemlock Hospice that the adelgid is “just like any other animal,” we want not only to encourage understanding of and empathy for the adelgic, but also to reflect on what we think about when we label it an “invasive species.”
According to the Oxford English Dictionary (accessed online the afternoon, November 22, 2017), invade means to enter in a hostile manner, or with armed force, and invasive pertains to an offensive (as opposed to defensive) invasion or attack. This usage goes back centuries, and has changed little over time. Invasion implies intention, or agency, on the part of the invader. Yet those organisms that we label “invasive species” lack agency and are not here (or elsewhere where they are unwanted) intentionally.
In cases like the adelgid, they entered North America unintentionally; for the adelgid, transported—long before we had APHIS or other border checks—on potted plants destined for the horticultural trade. In other cases (kudzu, honeysuckle, garlic mustard, among many others) we deliberately introduced them for ecological, aesthetic, culinary, or other economic reasons. But in all cases, like other stow-aways and immigrants, the adelgid and other such nonnative species looked for a place to sleep, to live, to eat, to reproduce, and to make better lives for its offspring.
Calling a species “invasive,” like calling it a weed, reflects our values, not traits or characteristics intrinsic to the species, its underlying biology, ecology, phylogenetic position, or evolution. And these values have changed through time, and may change again. So maybe rather than calling them invasive species, we should call them immigrant species, and reflect on how we’ve welcomed immigrants to the benefit of our societies, or tried to deport them or keep them out, to our detriment. Or better yet, just call it a species, an insect, the adelgid, and relate to it as another component of Earth’s wonderful biodiversity.