In a similar vein to rewilding, assisted migration aims to introduce plant and animal species to non-native ecosystems. The potential need of assisted migration stems mainly from climate changes caused by human activity. Carbon dioxide emissions in particular have increased dramatically since the Middle Ages (Marris 74). In conjunction with other gases such as methane and hydrocarbons, the atmosphere has been altered “such that it now retains more heat” (Marris 74).
The changes to the atmosphere play a crucial role in determining species’ need to move. Changes in temperature, for example, have already prompted some species to migrate to new areas while others try to adapt to the changes. For those species that have not yet migrated, either because they cannot relocate themselves or can still survive in the altered yet continuously altering climate, the option exists to proactively relocate such species to more suitable environment in the hopes of stabilizing the species’ population in the new geographical location.
While the notion has the best of intentions, assisted migration is not necessary. One of the arguments supporting assisted migration is the fact that “species richness shows declines” in the New York metropolitan area, as concluded from research done by Puth and Burns for Diversity and Distributions. However, assisted migration carries more risk than potential reward. There is no concrete evidence that moving certain species to certain new locations will ensure their well-being and survival. In the best-case scenario, the species will interact positively with its environment and the ecosystem will stabilize, successfully saving the migrated species. Ecologists opposed to the idea argue, “’organisms could die, because you don’t know exactly what they need to live-some specific microbes or microclimatic condition’” (Marris 77). The temperature of an area alone does not define the climatic conditions in which species live.
If a species’ living conditions is absolutely unbearable, it might find a way to a more suitable environment, just as birds often migrate south to warmer weather during the winter. For those species that are not as mobile, they may have the ability to adapt to the climate changes. However, prematurely moving them from their native ecosystems may jeopardize their abilities to adapt. Furthermore, that species may be vital to the balance of the native ecosystem and thus, removing it could disrupt the balance of the native ecosystem.
Another hesitation to assisted migration is the possibility of creating a “dreaded ‘invasive’ species that takes over and pushes out native species” (Marris 77). What if the assisted migration disrupts its new ecosystem enough that the native species cannot compensate for the new inhabitant? Scientists can only speculate how the ecosystem will react, effectively making assisted migration just a game of chance. Taking all of this into account, it is safer to just leave the species where they are and allow them to, hopefully, adapt to their environments while humans focus more on limiting the negative consequences of their actions.
Humans cannot save every plant or animal. Unfortunately, human activity has created a ripple effect on the Earth’s ecosystem that is now negatively affecting species around the world, directly and indirectly. However, there are too many variables in assisted migration that scientists cannot control, which may allow assisted migration to go awry. As a method of correcting the wrongs that human activity has done to the Earth and its ecosystems, assisted migration can have similar detrimental effects on the environment as human activity has already done, and two wrongs will not make a right.
