In Chapter 6 and Chapter 7 of Rambunctious Garden: Saving Nature in a Post Modern World, Emma Marris turns her focus to the benefits of introduced species. She explains that, although there has been a historical view that all species that were introduced to an area by humans are a threat to their new environment, this is not always the case.
Chapter 6 of the book opens with an example of an introduced species that harmed its new ecosystem but Marris goes on to provide many examples of cases in which the opposite has occurred. In many, if not most cases, introduced species do not do as much harm as people expect.
In Chapter 7, Marris discusses Novel ecosystems, which thrive with both introduced and native species. In some cases, biodiversity can increase with introduced species. In fact, introduced species may evolve in a new environment, thus increasing biodiversity.
I believe that, given the information from these chapters, an ecosystem that includes species which are not native is not necessarily a bad ecosystem and it may not be so bad to introduce a species to an ecosystem if it is done carefully. Although an ecosystem may be able to survive and even thrive after a species has been introduced, this is not always the case. For this reason, I believe that it is important that people continue to be extremely careful about introducing a nonnative species to an area. The information provided in these chapters does not justify an idea like rewilding in my opinion. It may, however, justify certain cases of introducing species, such as assisted migration of an endangered species that has almost no chance of surviving any other way, as long as it is done extremely carefully.
