Marris 6 & 7 – Exotic Species – 9/27
In Chapters 6 and 7 of Rambunctious Gardens, Marris presents two arguments on viewing exotic species. The conventional wisdom as of now is that exotic species are invasive. Marris quickly tells us, hwoever, that “the vast majority are not. Science is finding that some are quite well behaved and innocuous, or even helpful” (98). Be establishing this, Marris relates back to her original argument that we should embrace nature, not try and change it. She stresses that battling exotics is resourcefully consuming and unnecessary. Ultimately, she is saying that we, as humans, are the true enemy.
On one side of the argument are the majority of ecologists and conservationists who brands exotics as invasive. Marris presents extreme examples of this, including Bill Clinton’s executive order on war against invasive species and Shahid Naeem’s nighttime raids. There exists several arguments about how and why exotics do well in certain environments over others. Such explanations include lack of predators, lack of resistance, propagule pressure, and a reduction in the variety of life. Regardless of the reason, many still seek to obliterate non-native species from ecosystems in an attempt to revert back to a vague baseline. Marris combats these assertions by giving examples of beneficial organisms and inaccurate naming of exotics. She further informs us of how some ecologists are promoting and introducing exotics to help endangered species and hinder undesirable ones.
The opposing side of the argument are “a brave few” who embrace exotic-dominated ecosystems, novel ecosystems. Novel ecosystems refer to “the more dramatically altered systems” (114). In other words, an ecosystem whose composition of species has changed dramatically within the last few centuries—regardless of anthropogenic change. Marris hypothesizes that many are scared of change to explain the inclination of opposing exotic species. Exotic species usually kept in check by the surrounding organisms. The ecosystem as a whole is more stable and natural because of the lack of human intervention. Non-natives are hardly cited as the cause of extinction of other species. Even so, the extinction is a product of nature.
Ultimately, I agree with Marris and believe that the war on invasive species is an unnecessary one. Not only does it exhaust time and money, but it seems to be an endless circle which requires high amounts of attention. Exotic species are not new nor are they a recent phenomenon. I believe that “survival of the fittest” and evolution are a part of nature and therefore, should be allowed to happen on its own course. As Marris says, exotic species that adapt will create more diversity in the future. If a problem does arise to the point where the exotic does become invasive, they I think we should be able to deploy an extent of human intervention (which relates back to the notion of a rambunctious garden). “As the Earth responds to the changes we humans have made, does it make sense to destroy ecosystems that’s thrive under the new conditions?”
Marris Chapters 6-7
The negative perspective towards invasive species is fueled by emphasis on such “new germs and viruses [that] can make people and animals sick” or the “introduced species [that] can cost farmers and ranchers big money, as they destroy crops or displace more palatable species on the range” (Marris 99). By focusing on such cases as the introduced brown tree snakes species that “has killed off ten of twelve native forest-dwelling birds on the island of Guam,” (99) we are only considering the negative aspect of introducing new species to a region. When it comes to invasive species, similarly to other topics Marris addresses in her book, we could perhaps benefit from being more open minded with the ability to recognize the possible beneficial impact a species could have on the new ecosystem it is being introduced to. One example that illustrates the potential benefit of new species is that in Britain, where climate change caused chicks to hatch early, leaving them without caterpillars to eat. In this case, the newly introduced European Turkey Oaks were beneficial to the survival of the chicks as they brought with them wasps that served as food in lieu of the caterpillars. Examples like these are necessary as they illustrate the recurrent benefits that many so called “invasive species” can have on ecosystems. Marris brings up a valid point by questioning why we are inclined towards disliking the introduction of new species. I agree with the notion that perhaps it is because we “merely fear and dislike any change” (107). I also agree “the invasive species paradigm is so easy” and that it is simply convenient for us to implicitly immediately judge new species as invasive and dangerous and solely welcome natives in ecosystems (108). Ecologist Mark Davis brings up another valid idea, suggesting we should “forget about where they came from, identify species that are causing us problems…and then deal with them” and perhaps we could deal with each species as a “separate case” rather than categorizing based on native or invasive status (108). I appreciate Marris’ introduction of novel ecosystems, as they appear to be a good balance between complete conservation and radical moves such as assisted migration. Novel ecosystems are “defined by anthropogenic change but are not under active human management” (114). I am optimistic regarding the concept of introducing a species to an environment and allowing it to thrive, perhaps even assisting the processes of evolution and natural selection. My optimistic outlook towards the idea of introducing new species to an ecosystem stems from the positive results from scientists such as Ariel Lugo who “found that the novel forests [in his study], on average, had just as many species as native forests” (119). Although I, like Mascaro states, recognize that ”we will always have to deal with the risk [new species] pose to other systems,” I think we should further work towards and research novel ecosystems as it would be unfair to simply dismiss their potentially beneficial role in our environment.
