In Chapter 5 of Rambunctious Garden, Emma Marris discusses assisted migration – a process by which “species move around slowly, in geological timescales, often in response to climate shifts,” and humans assist animals in their movement (80). Climate change has had severe effects on the Earth, causing species to go extinct in some places and relocate in others; we now have a world “in which some places get more rain, others less, and climate patters become, on the whole, less predictable” (74). While humans seek to protect some species by quite literally transporting them to more suitable places in terms of climate, assisted migration remains risky because the species could go extinct or become a “dreaded invasive species that takes over and pushes out native species” in their new home (72). In addition to being relatively useful as a scientific tool, as the world continues to urbanize at rapid rates according to Puth and Burns’s New York’s nature, it’s worth considering further protection and guarantees of existence for rare species.
Scientists remain split on assisted migration, for the most part: Marris writes that “scientists are pretty freaked out by the whole idea” (78). The assisted migration movement is led by people like Unitarian activist Connie Barlow, who went as far as to “put up a website” defending her stance along with other citizens (81). Despite citizen passion for the idea, scientists held off on debating it mainly out of fear and the lack of an established baseline; ecologist Mark Schwartz wrote in an editorial that without “a baseline we have no target…every kind of management, including those that result in lost native species, is arguably a success. I fear such success” (80). Yet, against scientists’ resistance, “British Columbia became the first political unit to start systematically moving its trees” because climate chance was causing destruction by forest fire and dangerous species outbreak in the form of pine beetles – clearly, “something had to be done” (91).
Measuring the good and bad of ecological change is difficult in British Columbia and other urban, densely populated places. Puth and Burns discuss this further and show the general declines in species richness in New York City, New Jersey, and Connecticut, but they mention that they “found relatively few studies reporting location-specific species richness data in the New York metropolitan area” (16). As is the case in British Columbia where trees “may have a vigorous first few years and then slow down, as the climate changes, to something it is not prepared for,” studies on species in New York City lacked much significant data, according to Puth and Burns (92). In other words, for scientists to better understand concepts like assisted migration, they must not only debate the idea but do more research, short-term and long-term, on urban environments across the world. Until this is done, the majority of citizens and scientists will remain hesitant on assisted migration, which may be useful as a scientific tool in limited circumstances but not yet for widespread future use.
