In the third and fourth chapters of Rambunctious Garden, Emma Marris introduces the concept of Pleistocene rewilding. Pleistocene rewilding attempts to restore an area to its natural state before humans invaded it. Pleistocene rewilding does this by introducing species similar to those that lived in the area at that point in history. While Pleistocene rewilding does have its advantages, it also has many faults and risks.
One of the biggest reasons for Pleistocene rewilding is the protection of species and biodiversity. For as long as we have existed, humans have greatly influenced the ecosystems of our planet. We have caused the extinction of numerous species either directly by killing them or indirectly by impacting the ecosystem they adapted to so that they could no longer survive within it. Relatively recently, we have realized our impact and are now more careful about what animals we directly kill to avoid wiping out an entire species. However, we are still working on how to solve the problem of species at risk for extinction due to changes in their ecosystems. Rewilding attempts to solve this problem by restoring these ecosystems as much as possible.
In order to restore these ecosystems that have been drastically harmed by humans, rewilding involves introducing species to an area that are similar to those that once lived in that area but have since gone extinct. The idea is that these introduced species will take the roles of the similar species that they are replacing and the ecosystem will regain balance, allowing all species within the ecosystem to survive.
There are two major problems that I see with Pleistocene rewilding. The first is that the ecosystems have evolved since they were originally disrupted by humans and attempting to restore them to their pre-human state is not a viable solution as a result. The second is that the species that are being introduced, while similar, are not the same as those that were originally a part of the ecosystem and introducing a new species to an ecosystem can be very dangerous, even if precautions are taken.
Since humans first disrupted these ecosystems, they have been evolving to deal with the changes. Attempts to restore these ecosystems by reintroducing species similar to those that went extinct may not work well because the ecosystems may have evolved past their state in which that species was supported and needed. Even if it were possible to fully restore these ecosystems to their pre-human states, doing so may reverse any positive changes that have occurred as these ecosystems evolved.
The risks associated with introducing species are high, especially considering the evolution of the ecosystems. One of the ways humans harmed many ecosystems in the first place was by introducing invasive species. When a new species is introduced to an ecosystem, it may not be able to survive its new ecosystem or its new ecosystem may not be able to survive it. The species in a natural ecosystem evolved together and are therefore able to exist together. When a new species is introduced, this concept no longer applies. Although rewilding involves introducing species similar to those that were originally part of the ecosystem, they are not the same as those that went extinct and the ecosystems have evolved since those species went extinct. No one can know for certain exactly what impact the introduction of these species will have on the ecosystems today and it could actually lead to the extinction of some of the species we want to preserve through rewilding.
I believe that the downsides of rewilding are not worth the possible benefits and we should continue to look for better solutions to the problems Pleistocene rewilding attampts to solve.
