The foundation for the idea of assisted migration stemmed largely from climatic changes, specifically anthropogenic changes. Scientists believe that human emissions of certain gasses–like methane, carbon dioxide, hydrofluorocarbons–can be attributed to changing the composition of Earth’s atmosphere so it now retains more heat. The results include a warmer climate, sure, but also climate patterns, predictability, and rainfall. In 2003, it was ecologist Camille Parmesan predicted that “the average species’s range… moves 3.8 miles toward the pole every decade” (76). The solution, in some ecologists’ eyes, is assisted migration. It is the notion of taking a species from one ecosystem and transporting it into another in response to climate shifts, in hopes of providing that species with better conditions to survive and thrive.
Initially, this idea of assisted migration might sound somewhat logical. The intention is pure and sympathetic to those species that are having trouble withstanding and sustaining within the anthropogenic-changed-environment. Scientists who are in favor of assisted migration are ultimately concerned with increasing rates of species’ extinctions. On the other hand, “opponents are worried about the integrity of coevolved ecosystems” (78). Either argument strikes a chord with me, though I find myself siding more with the latter. I am a proponent of a laissez-faire environment, so-to-speak. I believe that evolution is the only force that rightfully should hold weight over the workings of the natural world. We, man, should not “intervene on [nature’s] behalf” (81). What really raises some skepticism is that there is “very little evidence that [assisted migration] is going to help” at all (93).
That being said, the usefulness of assisted migration in urban ecosystems is also in question. According to Puth and Burns, 75% of land area of New York City’s five boroughs has been developed for either residential, commercial, and/or industrial uses. Due to filling, dredging, and the like 80% of tidal wetlands and 99% of freshwater wetlands in the five boroughs have been lost. In a more general sense, out of 79 studies reporting location-specific species richness data, 26 of them had data from multiple time periods. Out of those 26, 17 showed decreases in species richness–a large percentage. The impact of urbanization proves to have been/be rather negative on the environment.
In this case, I tend to lean towards a regulated form of assisted migration. Camille Parmesan and Hugh Possingham provide a good guide for deciding when to move species. They “suggested that species should be moved if they can be feasibly transported, and if ‘the benefits of translocation outweigh the biological and socioeconomic costs and constraints'” (82). In my opinion, somewhat following these guidelines, candidates from those species that are categorized as both high-risk and feasible-transporters, can be relocated to a “target” habitat (so to speak) that, after being tested for conditions in all regards, are found fit for them. The importance, I think, is not complete and total special transportation, but only enough to try adapting and reproducing in the new environment. I, and many scientists, are wary of the unpredictable outcomes of moving species in fear of maladaptation–failure to adapt or becoming invasive species.
