|Lagoon Park in Santa Barbara by Van Atta Associates. Photo by Saxon Holt|
“Implicit in the proposals that call for the control and/or eradication of invasive species is the assumption that the native vegetation will return to dominance once the invasive is removed, thereby restoring the “balance of nature.” That’s the theory. The reality is something else. Land managers and others who have to deal with the invasive problem on a daily basis know that often as not the old invasive comes back following eradication (reproducing from root sprouts or seeds), or else a new invader moves in to replace the old one. The only thing that seems to turn this dynamic around is cutting down the invasives, treating them with herbicides, and planting native species in the gaps where the invasives once were. After this, the sites require weeding of invasives for an indefinite number of years, at least until the natives are big enough to hold their ground without human assistance.
What’s striking about this so-called restoration process is that it looks an awful lot like gardening, with its ongoing need for planting and weeding. Call it what you will, but anyone who has ever worked in the garden knows that planting and weeding are endless. So the question becomes: Is “landscape restoration” really just gardening dressed up with jargon to simulate ecology, or is it based on scientific theories with testable hypotheses? To put it another way: Can we put the invasive species genie back in the bottle, or are we looking at a future in which nature itself becomes a cultivated entity?” Peter Del Tredici from "Neocreationism and the Illusion of Ecological Restoration," Harvard Design Magazine.
I’ll confess: I am not an ecologist or an expert at ecological restoration. I have, however, worked with ecological restoration experts like Rutger’s Steven Handel. Consider my recent experience on a two thousand-acre agricultural site that we intended to convert into a mosaic of different native habitats. After going through the process of analyzing the site and preparing a restoration concept, my impression was that restoration was really not that different from the design process I use for any ornamental landscape. Obviously, the goals were different and our application of native habitats was based in a much more thorough site analysis. But the end result was the same: we imposed a human concept of what “nature” should be on the site. The end result would be entirely artificial and constructed.
|Vernal Pool created in an area that once wasa parking. Van Atta Associates. Photo by Saxon Holt|
Del Tredici’s conclusion for designers and gardeners is to “not to limit themselves to a palette of native species that might once have grown on the site.” He argues for using plants that will tolerate the conditions of the site, native or not, particularly in the tough urban conditions.
I have two responses to the article. The first is to agree with Del Tredici’s claim that ecological restoration creates “entirely artificial and constructed” landscapes. It’s absolutely true. It bursts the romantic notion that we can bring back plant and animal communities as they existed before Columbus arrived. It also challenges the myth that native plants are natural, good, low maintenance, and self-sustaining. They aren’t. They require human intervention. The sooner we can lose the mythology that “nature” will come back one day, the sooner we can get to the real work of creating entirely artificial, native landscapes that perform essential ecological services. See my posting here for more on this.
|Boardwalk at Lagoon Park in Santa Barbara by Van Atta Associates. Photo by Saxon Holt|
Of course, some natives—many of which are ubiquitous in the nursery trade—are not tough enough for urban sites. The natives that are widely available in the nursery trade are mostly selected for their ornamental value. We’ve hardly explored the full potential of native systems to address the environmental challenges of the day. To judge the adaptability of native plants based on the scant selection of natives that are currently available in the trade is preposterous. Mark Simmons, a researcher at The Lady Bird Johnson Center, is doing research that proves that many native plants are much tougher than non-natives and capable of solving many of our environmental problems. I will feature an article on his research later this month.
I love articles like Del Tredici’s. The debate over natives vs. exotic plants is really a debate about what is natural. I look forward to the day when we drop our romantic notions about nature existing somewhere “out there,” and can start to focus improving the ecology of the human-impacted landscapes that we encounter every day.
What do you think? I would love to hear other reactions to Del Tredici's article, especially any who have some experience or thoughts about ecological restoration.