Survival of the ‘ecologically literate’
A decade before Hurricane Katrina, ecologists and hydrologists expressed concerns about conventional approaches to flood control in the Mississippi. When disaster struck, the response exacerbated the catastrophe. Nina-Marie Lister discusses how we might avoid repeating this mistake in the future.
When mitigating natural disasters, communities often cling to the notion of ‘control’. But Toronto-based landscape ecologist and environmental planner Nina-Marie Lister wants you to consider unpredictability. Lister will be a keynote speaker at the 2017 Australian Institute of Landscape Architects conference.
JG: In “Ecological Urbanism,” you argue that ecology is now central to contemporary urban landscapes. How did this change occur?
NML: Ecosystems are now understood to be open systems that behave in ways that are self-organising and that are to some extent unpredictable. Change is built into living systems; they are characterised in part by uncertainty and dynamic change. For decades high school biology and ecology has taught – and in some places, still teaches –that ecosystems gradually and steadily succeed into stable “climax” states from which they don’t move unless “disturbed.” An old growth forest is one of the classic examples usually given. Yet we now know that change is not only built into these systems, but in some cases, an ecosystem is actually dependent on change. For example, fire-dependent forests contain tree species that require the extreme heat of fire to release and disperse seeds and to facilitate forest renewal—and sometimes, a shift in the complement of species. All ecosystems are constantly evolving and often in ways that are discontinuous and uneven.
Some of the classic examples of normal (yet often catastrophic) ecosystems change include forest fires, pest outbreaks, and significant storm events. These are taking on a new relevance today as we observe that the frequency and magnitude of storm events is increasing—a change which is being attributed to climate disruption. When major storm events happen (particularly in densely populated or urbanising regions), they can push an ecosystem into a new state which might ultimately be inhospitable for certain species, resources, or people.
We can shift our focus from managing ecosystems from a principally economic perspective to managing human actions within ecosytems. We’ve already seen evidence of this change, beginning in the conservation movement in wilderness areas.
A more timely and urban example of this paradigm shift in ecology and related management approaches can be seen in how we deal with floods. We can see this specifically through a gradual transition from flood control to flood management. At least a decade before the devastation of Hurricane Katrina, ecologists and hydrologists were warning that the US Army Corps of Engineers’ approach to flood control was effectively pushing the lower Mississippi basin towards a catastrophic threshold for change and potential collapse. Through a long-term policy of flood suppression, dyking and damming, coupled with the removal of coastal wetlands, and intensive settlement of the floodplains, the natural flood-adaptation mechanisms of the basin were comprised and impaired. When the big storm hit in 2005, we know that the devastation was catastrophic not only for the resources and the economy of the region, but for the lives of many of its most vulnerable citizens. In this very poignant example, it’s clear that traditional top-down or command-and-control engineering approaches to living systems don’t work.
JG: You quote landscape architecture professor Jane Amidon, who says, “The idea of nature has been remarried with the real thing, working ecologies.” What are some examples of this?
NML: The increased use of green infrastructure in our cities is a good example in which people can see the functions of a working ecosystem—whether in green walls that stabilise an embankment, or green roofs that provide food, or bioswales that filter and slow stormwater runoff. By making these processes visible, we have the potential to make ecology directly relevant to our publics. But really smart green infrastructures that are instrumental to productive ecologies go a step further: they facilitate hands-on learning or they require citizen participation in the ecological function. For example, many wetland creation and restoration projects rely on community volunteers for planting and maintenance; urban bioswales and green streets rely on stewardship by the community to function properly; and urban agricultural projects engage youth to work with native plants, bees, or chickens, etc, and become ambassadors for the project through outreach and education.
Green infrastructure is a practical way to understand working landscapes. As interest in local food continues to increase, we might think of food landscapes as a type of green infrastructure. Whether as vernacular community gardens or as a designed urban farm, or turning city parks into foraging landscapes with fruit and nut trees—these are all illustrations of our landscapes at work and in which people can and do participate. To my mind, this is a productive ecological urbanism. And so, making these functions visible, as opposed to just the ‘objects’ of nature – say a loved animal species – is a powerful way of communicating what an ecosystem does for us, and in turn, how we value those services.
JG: You argue that brownfield sites, once stripped of layers of toxic soils, are often locations for new “hybrid ecologies”, are they a good thing? And what are some examples?
NML: These are sites with both liabilities and opportunities, where ecological processes may be shaping the transformation of the site quite independently of human intervention. The very act of neglect opens a variety of ecological niches, exploited by plants, animals and people who use the site informally. Brownfields are often populated by co-evolving assemblies of introduced and native species which form new ecological communities—the kind that are usually associated with derelict lots, urban decay and the image of the shrinking city. But these hybrid ecologies can be useful.
Weedy plants (both native and non-native) are able to rapidly colonise disturbed and moderately contaminated sites; they can often tolerate and metabolise toxic materials such that they begin to remediate the site.
Interestingly, the environmental movement has become an inadvertent opponent of brownfield remediation using a hybridised ecological approach. A considerable portion of fast-growing, resilient but undesirable plants, commonly called “weeds,” are non-native. I would point out that Harvard ecologist Peter del Tredici, re-branded weeds as “wild urban plants,” alluding to their important role in the urban landscape. Not all non-native plants are invasive, but the unintended consequence of campaigns to eradicate non-native plants and to grow native species at all costs has been to overlook the potential benefits provided by non-natives in site remediation.
I want to emphasise that I am using the word “remediation” quite explicitly. I don’t like to use the word “restoration” in this context, because it’s rarely made clear what state we’re restoring towards and why. Restoration implies that a particular moment in an ecosystem’s evolutionary trajectory can be captured and preserved. But there is no pristine state in a world where the human animal is a participant in the ecosystems of which we’re evolved. The ecological restoration rhetoric has been over-simplified to the point where well-meaning citizen volunteers are pulling out any species that “don’t belong here.” There’s a xenophobic overtone to the language of restoration ecology that I find somewhat concerning. It’s not dissimilar to the language we use to describe people who “don’t belong”: non-natives, aliens, foreigners, exotics, intruders, etc.
JG: The lack of well designed wildlife crossings, has led to a 50 percent increase in collisions between wildlife and cars over the past 15 years in the U.S. Not only do these collisions take a huge toll of wildlife and people, but they cost the U.S. economy 8 billion a year. You advised the ARC Design Competition, which aimed to come up with a improved model for wildlife crossings. What are the next steps for the winning design by Michael Van Valkenburgh and HNTB? What is really needed to get these rolled out across the U.S. and Canada?
NML: Landscape architects are uniquely positioned to remediate this problem by designing new, “connective tissue” in the form of wildlife crossing infrastructure that must function structurally and ecologically, as habitat. On a continental scale, a network of crossing structures, both under and over roadways, can literally weave the landscape together Wildlife crossing structures present an interesting design challenge in that they must serve two clients: the human and the non-human. Of course, the wildlife client’s needs are less clear than the human clients’ needs. This necessitates considerable ecological research by the design team, usually with an ecologist or conservation biologist.
The short-term tangible goal for the ARC competition was to get a wildlife bridge built over the I-70 at Vail Pass which is a particularly problematic location for motorists and wildlife. This stretch of the I-70 has been studied extensively for over a decade, and the preliminary environmental impact study for the I-70 Corridor calls for a mitigation strategy. There is clear evidence that there is a need for crossing structure, and when you look at the data in terms of overall costs of vehicle-wildlife collisions to motorists and to the state– from personal damages to auto repair to insurance claims and premium increases to road maintenance—it’s staggering to see that nothing is being done. The competition has helped to raise awareness of the costs of these collisions to both humans and wildlife. To date, we’ve had a very positive response to the competition by the public as well as the Governor and the local Congressman. We’re currently at work on an implementation strategy with a number of stakeholders in the region.
Another longer-term strategy of the competition is to engage the public in a higher-level discourse about the importance of landscape connectivity and the role that connected, living landscapes play in the health of the environment. A key part of this communication strategy is to develop a traveling educational and experiential exhibit that brings the wildlife crossings to the public in a personal way. We also want to be able to use the structures themselves as an engagement tool for citizens to understand the need for them.
For example, we can use the structures as live monitoring sites around which schools could develop educational programming, and scientists can gather data for research. There are infrared cameras already installed at a number of crossing locations and while these are currently used for research purposes, they could also be linked to a live Web feed through which scientists, students, and the general public could track and observe various wildlife species in real-time. These cameras—or others installed specifically for this purpose on new structures—could also be used to feed visual data to a mobile device, perhaps as an application for smartphones. These visual and interactive strategies have the added benefit of allowing people to become more engaged with a landscape that so far has been relatively invisible to an urban population traveling at 60 miles an hour along the interstate.
A primary objective of the competition was to bring the cost of crossing structures down. We also wanted to show how we can use new materials, or how we can reinvent common, easily available materials ways that offer more flexibility and adaptation to the various landscape contexts in which these structures might be deployed. The jury was impressed with the winning entry on all accounts, but in particular by the use of an old material in a new, cost-effective way: precast concrete is a familiar material, the technology is well understood. The hypar-vault modules are cost-effective. This is principally because there are over 400 pre-casters throughout North America so transportation costs of getting the modules to where they are needed is reduced.
The jury noted that the benefit of using a familiar technology is that it is more likely to be accepted, even if in a new way. Once several of these structures are implemented, it’s more likely that we’ll see a willingness to experiment with different materials. This too was an objective of the competition, and several of the finalist teams developed innovative concepts using newer materials and engineering approaches, including cast-in-place thin-shell concrete, reclaimed beetle-killed timber, wood-core plastic laminate, resins and steel mesh. In this way we can consider the ARC competition as the beginning of a new typology of infrastructure—and a new role for landscape architecture.
JG: Instead of big theoretical approaches, you seem to say that any good ecological design has to be rooted in its natural place. How can landscape architects ensure they are doing this when they create these new ecological landscapes for people and wildlife in cities?
NML: Throughout this conversation I keep coming back to the centrality of scale and context in ecology. Our cities are much larger than in the past, and more of us live in cities. So in a very real sense, our cities are landscapes with functioning ecologies, including both natural and cultural components. Making ecological context (or “place”) is central to all my work. Of course, this is not a new idea. It’s simply a timely emphasis on a very old idea. One that civilisations always understood when the ability to survive depended fundamentally on the ability to know an ecosystem intimately.
Now that we’ve scaled up and supersized our cities, we’ve distanced ourselves from the ecological functions on which we ultimately but invisibly depend. The negative affects of this scaling are becoming clearer every day. But the good news is that landscape architects, ecologists and even some engineers (ok, many engineers) usually understand these ideas very well already. The fact that we are collaborating more than ever, finding creative synergies in our work, and taking on more complex projects are all good signs.
We are seeing a more infrastructural and performative approach to landscape design. There is growing recognition of the economic and social benefits of ecologically functional landscapes. But I think we can work towards a more sophisticated ecological urbanism in a number of ways. Chief among them is to make our designs reveal and celebrate the complexity of the ecosystems that define and sustain us. I am an optimist, and I believe design has the power to cultivate a more ecologically literate and engaged citizenry.
This text is an edited excerpt from an interview originally published by the American Society of Landscape Architects.
Nina-Marie Lister, MCIP, RPP, Hon. ASLA, is Associate Professor of Urban & Regional Planning at Ryerson University. She is a contributor to “Ecological Urbanism” and co-editor of “The Ecosystem Approach: Complexity, Uncertainty and Managing for Sustainability.” Lister recently served as the Professional Advisor to the ARC International Wildlife Crossing Infrastructure Design Competition.