Few of the world’s ecosystems have been left untouched by humans. While we can restore many ecosystems damaged by people to their historic function, some may be beyond repair and have become “novel ecosystems.” According to experts at the Society for Ecological Restoration (SER) conference in Madison, Wisconsin, some 36 percent of the globe’s ecosystems are now novel, meaning that more are now novel than wild. Some goods news though: the maximum extent of novelty, around 50 percent, was reached around 100 years ago. The percentage of novel ecosystems has actually gone down with more intensive agricultural practices that take up less land.
Novel Ecosystems and Shifting Values
Ecologist Eric Higgs, University of Victoria, put novel systems in a broader context. Walking through Southern Vancouver Island, he has seen many invasive species from elsewhere, but has been puzzled about what to do. There’s a limited amount of energy for pulling out every invasive plant species, particularly in areas totally over-run. Even if plants are removed, “the system will revert back immediately” to a state of invasion. At the global level, land use and climate shifts, invasive plant invasions, nitrogen deposition, and cultural changes mean a constant struggle against novelty.
In a new book Higgs and others published, Novel Ecosystems: Intervening in the New Ecological World Order, a model has been created to understand what kind of ecosystems we have today. There are “historical ecosystems,” which have had no change; “hybrid ecosystems,” which have “reversible changes;” and now “novel ecosystems,” where the changes are irreversible. Novel ecosystems are characterized by a “difference in ecosystem composition, structure, and function.” They have a “persistent self-organization,” even if they were created by humans. “They have a practical condition of irreversibility.”
Restoration ecologists mostly work in the area of hybrid ecosystems, trying to restore them to historical ones. While this work is important, Higgs argues that “we have to have flexible goals in some systems.” For example, he pointed to the typical “landscape mosaic” found in exurban or peri-urban areas. There, the landscape is often segmented into hybrid and novel systems. And there, restoration ecologists have to “restore and intervene responsibly.”
In the face of this overwhelming struggle against novelty, there has been a shift in values among society. Years ago, restoration ecologists wanted to restore ecosystems to their “historic fidelity” as much as possible. Now, ecologists, scientists, and landscape architects discuss the value of novel ecosystems’ services, which to some extent are plant-agnostic.
Perhaps reflecting the shift in values, Higgs said “ecosystem services can be achieved in different ecosystems,” meaning that novel systems, no matter how different they are from historic ones, still have some value. Still, Higgs cautioned against those who think novel ecosystems are somehow beneficial, and the way to go in the future. This view point has been promoted by a number of scientists, and articulated well by Emma Marris, author of Rambunctious Garden: Saving Nature in a Post-Wild World, and others in a recent New York Times op-ed. Higgs thinks this point of view is a bit dangerous, as the Anthropocene, the globe as managed by man, could raise problems with biological diversity. “We have to be careful.”
He said all the debate about novel ecosystems and ecosystem services may prove fruitful though. The old model of ecological restoration was “history as template, single trajectory, and an emphasis on structural composition.” The new model, which he deemed “ecological restoration 2.0,” calls for “history as a guide, multiple trajectories, processional emphasis, and pragmatic goals.” Expectations are diminishing on one hand, while “possibilities are enlarged” with novel systems. “Novel ecosystems can bolster restoration goals for systems in rapid change.”
Planet Now More Novel Than Wild
Mike Perring, University of Western Australia, seeks to quantify the extent of novel ecosystems across the globe. He said “novelty is not new,” so he’s trying to figure out the current and historical extent and how things have changed over time.
Perring and his team have used “proxies” such as land-use maps and population counts. Areas used by humans and close-by areas not used are basically novel. In addition, areas previously used but no longer used, areas where there was “population in the past,” will sometimes still be novel.
While there are different land-use models, Perring estimated that a vast amount of the globe has been converted for human use, meaning about 36 percent of the world’s ecosystems are novel. Excluding the ice-covered parts of the planet, this means that more of the planet is novel than wild.
According to the models Perring used, there has been lots of change over the past 250-500 years. “The wild has been going down over time.” But the good news may be the novel is going down, too. The maximum amount of novelty, around 50 percent, was hit around 100 years ago. Novelty has gone down as humans have cultivated land more intensively.
Perring wondered whether we have reached irreversible thresholds of novelty or not, as well. With ozone, carbon dioxide, and acidification levels changing with climate shifts, there are definite implications for ecosystems.
Novelty in the Era of Climate Change
According to Brian Starzomski, University of Victoria, all ecosystems, even novel ones, are rapidly changing with climate shifts. “You basically need to move 110 meters per year to follow your climate.” Climate shifts are expected to only accelerate, further exacerbating challenges related to novel ecosystem management.
Starzomski asked, “How do we adapt to and manage ecosystems that we have never experienced before?” Ecosystem restoration must also change as the climate does. As an example, he discussed the Jasper National Park in the Canadian Rockies, where leading-edge peripheral populations are losing their range due to climate change. Also, the Garry Oak ecosystems along the Pacific Northwest are experiencing “novel conditions” that challenge restoration paradigms. He said in Canada, nine national parks “no longer contain their original climate conditions.”
The Challenge of Measuring What’s New
Finally, ecologist Jim Harris discussed how difficult it is to measure novel ecosystems, given “no two ecosystems are identical.” He added that “finding the degradation symbol may not be obvious.” An ecosystem may appear fine on the surface, but the hydrological systems may be shutting down because of subtle shifts in groundwater, or the soil compositions may be changing. In addition, some systems are extremely challenging to pin down. “Some exhibit multiple stable states.”
To measure novel ecosystems, one must look at reference sites. But how many do scientists need to look at to be sure? Without enough examples, restoration ecologists can end up with “rigid prescriptions that produce fragile systems, or worse, landscape collapse.”
In dealing with novel ecosystems, landscape architects and restoration ecologists need a “big team,” with lots of data on species and human populations. Subtle surveys collecting lots of on-the-ground information are really critical. “We can’t just deal with simple approaches like numbers and arrangements. With ecosystem services, there is a lot to measure here.”
Image credits: Novel Ecosystem in Hawaii / Image credit: Emma Marris, ASLA Interview.