An invasive species is an invasive species, a commentary at Baltimoresun.com, asks, “What's the difference (between a mute swan and a nutria)? The only significant one is human aesthetics. People love to look at swans with their white feathers and elegant long necks. Not so much with nutria, which might generously be described as a cross between a beaver and a rat.” The difficulty inherent in trying to reconcile human aesthetics with natural selection is at the root of the problem. I call this wicked inconvenience the conundrum of dangerous beauty.
When it comes to landscape and garden design, stakeholders are divided between those for whom beauty has equal weight with fundamental ecosystem services and those for whom regulating services are paramount. The concept of ecosystem services includes basic regulation services such as CO2 exchange and provisioning services such as genetic diversity. And ecosystems include services such as providing food and informing cultural references such as aesthetics. In other words the actual debate is about which service is more important.
The problem is in the question and the assumption that one side of ecosystem services or the other should be more heavily weighed. There is a third way that says all services are equally important, and that the task before us is to find balance within the dynamics of a system that tends to oscillate wildly between extremes. We should not be choosing between clean water and our individual sense of beauty, but rather selecting a mix that brings the extremes back into balance. Those who seek beauty want clean water as much as those who seek a pristine environment with little measurable impact from human activities.
The disagreement cannot be a matter of what looks good for there is no disputing taste so aptly spoken by the Romans (non est disputandum gustibus). Beauty is the relationship between form and sentiment in nature. Invasive species confound the relationship at many levels. The fragrance of the rose provides the sentiment based upon a cultural tradition rooted in the writings and stories of the past, but what of form in this relation? The form is the general human capacity to link to this rose the mysteries and feelings of the fragrance identifying among many traits color, setting and experiences. An alternative relationship could be the observance of the form of interactions with the sentiment based upon the implications of sustainability.
Paraphrasing a General Lee: It is good that invasive species are so destructive lest we grow too fond of them.