The consequences of rapidly accelerating climate change have put ecologists and conservationists in a moral and ecological pickle. The debate over assisted migration– whether humans should intentionally plant or move species into areas outside their native ranges– is highly controversial.
Climate change has already driven many species out of parts of their native ranges and will drive many species to extinction. As global temperatures rise, climate regimes are shifting to higher latitudes, with places now experiencing climates that were historically characteristic of places closer to the equator. The climate of Northfield has already shifted approximately 200 miles to the south– our current climate was once the climate of Des Moines, Iowa.
Plants that are suited to colder climates will continue to die off at the lower extent of their ranges, replaced by species suited to warmer conditions. To survive this shift, species will need to adapt to changing conditions or colonize newly suitable habitats. However, climate change is accelerating at a rate that is simply too fast for many species to naturally disperse into new suitable habitats. Proponents of assisted migration argue that helping these species disperse into areas immediately adjacent to their historic ranges is just a boost to an otherwise natural process. Additionally, many landscapes are already so fragmented by developed land that the potential for natural migration is severely limited.
Those opposed to assisted migration proposals cite that any risk of introducing new invasive species to an ecosystem is a risk not worth taking. But do the risks of losing species to extinction by “letting nature run its course” outweigh the risks of potentially introducing new invasive species?
It’s worth keeping in mind that nowhere on the planet is truly free of human interference. Anthropogenic climate change is a human intervention in itself. The “natural” landscape of the Arb has only recently been planted to resemble what it looked like before European settlement; most of the Arb’s land was agricultural through the mid 1900s. Extensive ecological restoration work is in itself an assisted migration of sorts, so what is really holding us back from planting for the future?
–Samara Kroeger ‘21, for the Cole Student Naturalists
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