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Climate & Energy
Managing Ecosystems in a Changing Climate: What to do - If Anything
V. Alaric Sample

Rambunctious Garden
Rambunctious Garden: Saving Nature in a Post-Wild World
By Emma Marris
Bloomsbury Press, 2011. 210 pp. $25.

Saving a Million Species
Saving a Million Species: Extinction Risk from Climate Change
Edited by Lee Hannah, with foreword by Thomas Lovejoy
Island Press, 2012. 411 pp. $35.

Emma Marris’s Rambunctious Garden: Saving Nature in a Post-Wild World, is one of the latest contributions to a growing genre of environmental science literature that questions not only the effectiveness of established conservation methodologies and practices, but their fundamental goals as well. As her subtitle suggests, Marris perceives a “post-wild” world in which there is no ecosystem left whose functioning has not already been altered by human activity. Building on the basic thesis introduced into the public consciousness by Bill McKibben in his book, The End of Nature (Anchor Books, 1990), Marris focuses primarily on the ubiquitous effects of climate change on native biodiversity. She accepts these as a given, and devotes most of the book to questioning what we can actually do about it, or more pointedly, what should we do about it? Her answers to these queries leave one wondering whether a more appropriate title for her book might be Rambunctious Garden: or, How I Stopped Worrying and Learned to Love Species Extinctions.

As the profound implications of The End of Nature have begun sinking in with conservationists, the basic concepts of naturalness and ecological restoration have been thrown into flux. Efforts to restore ecosystems to some ideal past state have come to be regarded as rather arbitrary (pre-Industrial Revolution? pre-Columbian? pre-Transpacific Migration?). With the goals now uncertain, ecosystem restoration itself—and whether it is even possible— also has come into question. This is particularly troubling in the restoration of forest ecosystems, with efforts currently under way around the world to repair the damage to tropical, temperate, and boreal forests from past exploitation. First, since there is not an acre of forest on the face of the planet whose ecological functioning does not already reflect human influence,Marris argues that the very concept of “natural” is in fact a purely human artifice. Second, with the concentration of atmospheric greenhouse gases already at unnaturally high levels and projected to increase still further for the next century under even the most optimistic projections, the backdrop against which scientists were trying to understand the complex functioning of natural ecosystems has gone from relatively stable to highly dynamic. Conservation biologists are being called upon to hit a moving target when, for most forest ecosystems on the planet, they had yet to figure out how to hit the target when they thought it was sitting still.

Marris notes that among environmental activists, it was until recently taboo to discuss climate change adaptation, because it would shift the policy focus away from mitigating climate change as much as possible by regulating greenhouse gas emissions. Times have changed. With momentum for climate change that is already gathering, and the seeming inability of governments to bring about any meaningful reductions in carbon emissions, the preponderance of climate change research is already shifting away from mitigation strategies to adaptation strategies. Marris too moves quickly past the mitigation question and into a detailed discussion of various adaptation strategies for conserving biodiversity in the face of climate change, why many of these are still anathema to conservation biologists, and why most are doomed to failure anyway.

Recent efforts by scientists in British Columbia are highlighted as way of illustrating one of these strategies, known as “assisted migration.” Assisted migration is the term used for several different techniques aimed at facilitating the relocation of a species from its current habitat range, to where its optimum range is expected to be at some point in the future as regional climate shifts occur. One wonders whether these scientists drew their inspiration from what Canadian hockey star Wayne Gretzky once described as the secret to his success: while others skate to where the puck is, he skates to where the puck is going to be.

In the northern hemisphere, the ecological puck is generally heading further north or higher in elevation. Forest products are a major component of the British Columbia economy, and significant investments are being made to experiment with transplanting commercially important tree species to the far northern limits of their current range, in expectation that climate change will create increasingly suitable growing conditions over the lifetime of these trees. As it happens, tree seedlings are remarkably specific to a narrow range of latitude and elevation where their parents resided. They might survive a long-distance relocation, but they often will not thrive and much of their commercial value will be lost. Marris concludes that, while commercial forestry enterprises will have a continued incentive to attempt assisted migration, they will have to put up with high levels of reforestation failures, poor tree form, and high susceptibility to insects, diseases, and drought as they attempt to “forward position” commercial tree species in areas that turn out to be too warm, too cold, too dry, or too wet.

Silver Meadow on the Uinta-Wasatch-Cache National ForestSpecies of no commercial value are pretty much on their own. Most conservation biologists are reluctant to manipulate ecosystems by intervening with selective species transplantations. As Marris notes, there will be a certain randomness in which species have their seeds picked up and transported north by favorable winds or in the digestive tracts of migratory animals. But individual species do not exist in isolation. They are components of ecological communities—ecosystems—where they live in complex interrelationships with other plant and animal species with which they have evolved over a long period of time. As these random transplantations take place, some species find themselves among strange new neighbors as they trek northward. Their old neighbors meanwhile are noticing new arrivals from further south, some of which will take on the aggressive characteristics of invasive species. Ecosystems all along a north-south axis will find themselves “torn apart” by these differential arrivals and departures of only selected members of ecological communities. Some will re-assemble themselves into new communities and become integral to new ecosystems. No one can really predict what these new ecological communities will look like, only that they will be different from anything we’ve seen before.

Not that there is anything wrong with that, in Marris’s view. In a section on “novel ecosystems,” she argues that many of these new assemblages of species, often the result of intentional introductions, can exhibit high degrees of species diversity, and can be highly productive. Citing examples such as discoveries made during failed attempts to eradicate feral plantations of nonnative pines on the island of Puerto Rico, Marris marvels that “the exotic-dominated ecosystem was functioning better than nearby native forest, if function is measured as brute production of biomass.” Is it?

From this perspective, efforts to extirpate invasive species are not only virtually impossible, they are ecologically pointless and possibly counterproductive from a conservation standpoint. The determination of which species “belong” and which do not is, as Marris sees it, more of a human value judgment than a function of objective biological science. Who is to say that the particular assemblage of species that was on the scene when the first humans arrived was any more “right” than whatever assemblage came afterwards? It is quite likely that this supposedly primeval assemblage was itself quite different from what was on the landscape a thousand years before. Marris’s message: don’t worry, be happy. Be more open-minded and receptive, and recognize the intrinsic values there may be in the novel ecosystems and the scrambled ecological associations that will result from climate change in the decades ahead.

Rambunctious Garden would seem to be a textbook of realpolitik as applied to the impending, inevitable changes in the global climate, and the resulting ecological new world order. Whenever change of any kind takes place there will be winners and losers, and life is about to get very tough for the species that are the losers. Sorry about your luck.

Lee Hannah, Tom Lovejoy, and other contributors to the edited volume Saving a Million Species: Extinction Risk from Climate Change, seem less sanguine about the species extinctions likely to result from climate change. This book updates and expands upon Lovejoy’s and Hannah’s earlier groundbreaking text Climate Change and Biodiversity (Yale University Press, 2006) in terms of defining the drivers of species extinction from climate change, and refining the earlier estimates of likely extinctions. The later book is much thinner in terms of conservation responses and strategies for actually limiting such extinctions and, unlike the 2006 book, its successor lacks a section on policy responses. In the wake of the Kyoto Protocol’s questionable impact on reducing greenhouse gas concentrations, and Congress’s rejection of legislation aimed at controlling US carbon emissions, perhaps they’ve given up on policymakers.

Hannah and Lovejoy do not perceive a benign exchange of new species and new ecological communities for the old, as Marris suggests. Rather, these authors anticipate a steady, perhaps accelerating net loss of species, resulting in ecosystems that are less diverse, less stable, and more prone to further disruption from future human and natural disturbance. Species and ecosystems have always evolved and adapted to climatic shifts—say, following the Pleistocene. However, the current episode of greenhouse gas-driven climate change is taking place not over millennia but decades, they point out. As miraculous as the process of evolution may be, successful adaptation, mutation, and speciation take place over longer timeframes.

Marris and these authors seem to agree that, in spite of the geologically rapid and ecologically significant degree of climate change that is expected over the next century or so, the planet will survive, as will many of its current life forms. Will ecosystems and communities disassemble from the differential migration of species, and then simply re-assemble as novel ecosystems that are just as diverse, productive, and intrinsically valuable as their former selves? Or will we see a gradual extinction of a large percentage of today’s species, and their replacement by fewer, more competitive species, especially those with a propensity to adapt to human-influenced environments? Will climate change accelerate the global propagation of human-adapted species that paleontologist Peter Ward argues began in the 16th-century Age of Exploration, with the first major waves of intercontinental species transplantations (Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future (HarperCollins, 2007); Future Evolution: An Illuminated History of Life to Come (Henry Holt&Co., 2001)?

In the midst of all this debate among ecologists and conservation biologists, the world’s natural resource managers—those who each day make decisions that will determine the course of forests and other ecological communities under their care—are looking for guidance. If the future is to look less like Ward’s dystopia of simplified, coarse ecosystems barely worthy of the name, and more like Marris’s happy, rambunctious garden of human managed landscapes and a few altered yet still diverse “post-wild” places, then how does this change the goals, practices, and even the fundamental ecological science that guide today’s managers of forests and related terrestrial ecosystems? Natural resource managers are focused increasingly on how they can sustainably meet the needs of 10 billion people, considering that when concerns over resource scarcity galvanized the Conservation Movement a century ago world population was considerably less than 2 billion people. As these twin megatrends of population growth and climate change converge to form their own “perfect storm,” what changes must be made from the ways in which we managed for conservation in the past, to ways in which we must manage for sustainability in the future?

V. Alaric Sample is president of the Pinchot Institute in Washington, DC.
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