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13 May 2013

True Nature: Revising Ideas On What is Pristine and Wild

New research shows that humans have been transforming the earth and its ecosystems for millenniums — far longer than previously believed. These findings call into question our notions about what is unspoiled nature and what should be preserved.
By fred pearce

Are there any pristine ecosystems out there? The evidence is growing that our ideas about virgin nature are often faulty. In fact, the lush rainforest or wind-blown moorland we think is natural may be a human creation, with alien creatures from distant lands living beside native species. Realizing this will change our ideas about how ecosystems work and how we should do conservation.

We like to think that most nature was pristine and largely untouched until recent times. But two major studies in recent weeks say we are deluded. In one, Erle Ellis, a geographer at the University of Maryland Baltimore County, and colleagues have calculated that at least a fifth of the land across most of the world had been transformed by humans as early as 5,000 years ago — a proportion that past studies of historical land use had assumed was only reached in the past 100 years or so.

The human footprint was huge from the day, perhaps 60,000 years ago, when we began burning grasslands and forests for hunting, according to the Ellis study. It extended further with swidden “slash-and-burn” agriculture, and became more intense when farmers began to domesticate animals and plow the land.

This seems odd given how few we were back then — tens of millions at most — and how primitive our technology was. But, says co-author Steve Vavrus of the University of Wisconsin, “early farmers didn’t need to be as
As much as a tenth of trees in the Amazon grow on man-made ‘dark earths’ created by pre-Columbian farmers.
efficient as modern farmers and therefore, counterintuitively, they used much more land per capita.” In other words, they spread out.

In fact, they farmed large areas that today look like virgin forests. But we now know that as much as a tenth of the trees in the Amazon rainforest grow on man-made “dark earths,” or terra preta, which archaeologists believe were created by pre-Columbian farmers who added organic wastes and charcoal to improve nutrient supply and boost yields.

Much of the Amazon, Ellis concludes, is actually forest regrowth. Or — judging by the profusion of fruit trees and other valuable species still growing in terra preta areas – perhaps overgrown gardens.

Other tropical rainforests also seem to have been farmed. In the past couple of years, James Fraser of Lancaster University in England has found dark earths in until-recently forested West Africa. And last year Doug Sheil and colleagues reported similar findings from Borneo. Other studies have found oil-palm nuts over wide areas of the central African jungle, suggesting the place was covered in palm-oil plantations 2,000 years ago.

Nor is this just about rainforests. The bison-grazed plains of North America were remade by Native Americans long before Europeans showed up. Many of the mist-shrouded treeless grasslands of the tropical Andes, known as the paramos, are the result of burning and grazing after locals cut down the natural forests centuries ago. In colder climes, the Scottish highlands tell a similar story.

Just as geographers and archaeologists are hard-pressed to find untouched landscapes, so biologists are having similar trouble locating pristine ecosystems.

Paramo Ecuador Andes
Photo by Steffen Foerster
The treeless paramos grasslands in the Andes evolved after forests were cut down centuries ago.
A new book, Novel Ecosystems, edited by Richard Hobbs of the University of Western Australia and others, shows how many superficially natural ecosystems are heavily influenced by the introduction of alien species. Whether intentional or accidental, most introductions seem to have human origins.

This is disconcerting. “Over large parts of the globe, the ‘wilderness’ that people refer back to never existed,” says one of the book’s authors, Michael Perring, also of the University of Western Australia.

Nature has always had open borders for alien species on the move. Those itinerants may have been a driving force of evolution. But human activity has dramatically increased their travel options. We move many deliberately, as commercial crops or domesticated animals, for instance. Today, others can hitch a ride on ship hulls or in ballast tanks, aboard planes or on the wheels of trucks or the backs of domesticated animals. This phenomenon seems to have been going on for much longer than we sometimes imagine.

Conventionally, we regard these unwanted interlopers as a curse, destabilizing ecosystems and devouring indigenous species. Sometimes this is true, as Hobbs and his co-authors acknowledge. But they point out that, in the 21st century, aliens make up a substantial fraction of the planet’s biodiversity, and many are actively useful, even essential parts of ecosystems.

Extinctions caused by new arrivals happen and can sometimes be devastating. The brown tree snake from New Guinea is eating its way through the wildlife of Guam, after arriving on a military plane. The zebra mussel, which came from the Black Sea region in the ballast water of ships, is notorious in the U.S., which returned the favor by inadvertently sending the Black Sea a jellyfish that devastated that ecosystem. But actually, such events are rare. Mostly, invaders swiftly settle down and become model eco-citizens, pollinating crops, spreading seeds, controlling predators, and providing food and habitat for native species. After a while we forget about them, or learn to love them. Where would North American be without the European honeybee?

Usually, invaded ecosystems end up with more species than they had before. Places like New Zealand, Hawaii, even the Galapagos islands — all notorious for species invasions due to human activities — are actually all more biodiverse than before. Ellis calls them “anthropogenic melting pots.”

Scientists who research the invaders and their hosts are discovering much that is intriguing. British researchers recently reported finding two species
In the new analysis, ecosystems begin to look a lot more accidental and transient than niche theory suggests.
of native tits that have learned to eat the larvae of a wasp that was introduced to the country from the Middle East 180 years ago and that lays its eggs on the Turkey oak, another introduced species. The tits are spending more and more time in the trees, eating the larvae, especially in spring because climate change means their young now hatch before their previous food source, leaf-eating moth caterpillars appear.

Novel ecosystems are different, but not necessarily worse. San Francisco Bay, for instance, is widely regarded as the most invaded estuary on the planet. But that didn’t stop the U.S. government submitting it in January to the Ramsar Convention as a wetland of international importance, because of is a “key habitat for a broad suite of flora and fauna and a range of ecological services.” Much of its rich biodioversity — and some of its ecological services — is due to its alien species.

Aliens may even contribute to rewilding those parts of the planet we no longer need. In Puerto Rico, abandoned sugarcane fields across half the island have sprouted new forest ecosystems, largely thanks to the invasive power of non-native species such as the African tulip tree, says Ariel Lugo of the International Institute of tropical Forestry. The tulip tree proved attractive to native birds and insects and now, after a few decades, native trees species have started to recover too.

The case that we have to accommodate the alien and novel when trying to conserve nature and restore ecosystems was made by Emma Marris in her 2011 book Rambunctious Garden. But the new analysis goes beyond that simple pragmatism, because it suggests we need to rethink many ideas about how nature works, too.

For instance, it calls into question the conventional view that ecosystems such as rainforests are complex machines, or super-organisms, that have emerged through a long process of co-evolution of species to fill ecological niches. But, if that is so, asks ecologist James Rosindell of Imperial College
Change, including rapid and disruptive change, is a natural feature of the world,’ says ecologist Stephen Jackson.
London, how come alien species are so good at invading other ecosystems, frequently becoming fully integrated neighbors?

Ecosystems begin to look a lot more accidental, random, and transient than niche theory would suggest. They are constantly being remade by fire and flood, disease, and the arrival of new species. They are a hodgepodge of native and alien species. This fits a rival model for how ecosystems work called “ecological fitting,” first articulated by the legendary U.S. ecologist Daniel Janzen of the University of Pennsylvania. He said that co-evolution is a bit-part player in ecosystems; most of the time, species muddle along and fit in as best they can.

Far from reaching some equilibrium state with niches filled, ecosystems have always been in a constant state of flux, says Stephen Jackson, of the Southwest Climate Science Center in Arizona, in Novel Ecosystems. “Change, including rapid and disruptive change, is a natural feature of the world.” Humans may have dramatically speeded that up, but novelty is the norm.

In that light, we need to look afresh at conservation priorities. Novel ecosystems cannot be dismissed as degraded versions of proper ecosystems, nor can alien species be demonized simply for not belonging. If novelty and change is the norm, Hobbs and colleagues ask, does it make sense for the growing business of ecosystem restoration to try and recreate static historic ecosystems? By doing that, you are not creating a functioning ecosystem; you are creating a museum exhibit that will require constant attention if it is to survive.

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New research shows that scientists have significantly overestimated the damage that logging in tropical forests has done to biodiversity, a finding that could change the way conservationists think about how best to preserve species in areas disturbed by humans, Fred Pearce writes.
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Conservationists, others argue, also need to be more positive about the ecological benefits of traditional farming. A widely held view is that we need more intensive industrial farming in order to provide the food the world needs while leaving land for nature. But that assumes farms can have no ecological value. Yet traditional farming methods are often better seen as novel ecosystems rich in biodiversity — havens for wildlife that is worth protecting.

Christian Kull of Monash University in Australia recently called for the protection of novel farming systems that operate within forests, such as the rubber gardens of Indonesia and the cacao farms of Cameroon, which “blur boundaries between human and natural, native and non-native, production and conservation.”

The good news from all this is that nature emerges as resilient and adaptable, able to bounce back from the worst we can throw at it. And that raises a final heretical question. In an era of coming rapid climate change, if any species are going to thrive surely it will be the desperadoes, stowaways, and vagabonds that have been hitching a ride around the world with humans — species that, in some respects, closely resemble us. So if novel is the new normal, should we be encouraging their travels, rather than stopping them at the border?

ABOUT THE AUTHOR


Fred Pearce is a freelance author and journalist based in the UK. He serves as environmental consultant for New Scientist magazine and is the author of numerous books, including the newly released The Land Grabbers: The New Fight over Who Owns the Earth. In previous articles for Yale Environment 360, Pearce has written about growing evidence that involving local communities is the best way to protect forests and explored the question of whether environmentalists increasingly are taking anti-science positions.
MORE BY THIS AUTHOR

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COMMENTS


Is there proof that industrial farming is more productive than small scale? Some figures say reverse.

Besides small farmer usually eat more local which has a huge amount of ecological benefits when multiplied by billions.

Industrial farming is just more profitable, meaning it cuts on labour force and drive people out of land and out of work. It is based on machinery and simplification which can by no means be compatible with an healthy ecosystem that relies on complexity.

It is less about subsidising small agriculture, for conservation, than stopping the flow of tax payer money toward big farming. Besides it is proven, via leaks, that the American Administration is lobbying for GMO, using worker money to kill small farming all over the world. There is the problem: an administration owned by private interest.

Posted by kervennic on 15 May 2013


Probably much earlier. The tables began to turn at the dawn of Homo, ca 2.5 mya, at the end of the Pliocene and transition to the Pleistocene. Australopithecus was still around and, perhaps, was also getting in on the action. An upgrade of the tool kit --- improved social organization, better weapons and accessory technology --- led to more protein in the diet, a larger brain, and increased numbers. These allowed hominins, the human clade, to begin dishing it about this time.

The first hominins to seriously diminish the biota were probably kleptoparasites. They took animals killed by large (Werderlin and Lewis 2013. PloS1). They ate what the big cats drug in.

Posted by Don Strong on 15 May 2013


Many of the ecosystems referred to in this article are what modern permaculture practitioners refer to as "forest gardens" (http://en.wikipedia.org/wiki/Forest_gardening).

These forest gardens bear no resemblance to the geometric monoculture gardens or industrial farms that we utilize for food production in the west. They are essentially integrated plant systems from canopy to fungal layer that produce ever greater quantities of food with less and less human input required each year (the antithesis of modern agriculture where the inverse is true). Forest gardens have far greater yields per acre and are far more ecologically sustainable. And, yes, they are commercially viable alternative to industrial agriculture as the reduced input equates to reduce cost to the farmer. These systems are designed to last thousands of years, which is why we find "abandoned" ones still thriving thousands of years later without any humans tending them. Thankfully, it's a farming practice that is being reintroduced throughout Asia, Africa, Australia and even here in the U.S.

Also, no plant is truly "native." Some have just been in a particular ecosystem longer than others.

Posted by Aaron von Frank on 16 May 2013


Pearce has demonstrated that he knows how to paraphrase a book, but his knowledge and understanding of the ecological issues of biological invasion is greatly lacking. Through gross oversimplification, he has created a misleading impression of the realities of biological invasion and human alteration of ecosystems.

For one, he has presented no examples based in fact and hard evidence of human alteration of the environment that compares to the modern era. Yes, it is well known now that humans have manipulated vegetative cover using a variety of means for agriculture and habitat management over the past 10,000 years. But the recreation of the vegetative landscape over time is still riddled with uncertainties, and to imply that 2,000 years ago, for example, that central Africa was covered with palm-plantation is drawing a conclusion from evidence that is not fully in, purely speculation.

There have also been several examples of relatively stable ecological states. Change is the norm in nature, and there is no such thing as a static equilibrium, but nature WANTS to establish equilibrium and is constantly moving toward it in a world of stochasticity. Take the temperate rainforests of North America, an ecosystem with long-term human habitation, but one in which relatively little large-scale disturbance had occurred until western settlers began deforestation. For millenia, these massive forests existed in a relatively stable, productive, and moderate climatic and geologic environment, enabling tree species to attain record biomass and size. Biodiversity, especially that of macroinvertebrates, has historically been typically very high in these old-growth stands.

The statement that Hawaii is "more biodiverse" because of invasive species is bogus as well and not supported by fact or evidence. Hawaii has experienced more extinctions and has more critically endangered species than any other US state or territory, especially when it comes to birds. The number one threat to these species has been loss of native habitat.

Finally, nature and the planet may recover just fine from massive global change. But how many human generations is Pearce willing to wait until it is habitable again by our species? The fact is, the scale of change that the earth's ecosystems are experiencing is unprecedented during the rest of human history by an order of magnitude, especially when climate change is factored in. Pearce's arguments seem to lack critical thinking and come across as lazy justification for the current state of affairs. Nature has not, until now, seen the worst humanity can throw at it, and if current trends continue, the worst is yet to come.

Posted by Ross Geredien on 16 May 2013


With no offense intended, much of this article seems to cover ground already covered by William Cronon in his 1995 book 'Uncommon Ground: Toward Reinventing Nature.' Other than some details, I think the concept Pearce focuses on already has been well–established.

However, I do agree with Ross Geredien's comments. There is a matter of scale that Pearce ignores. But as every ecologist knows, scale is very important.

I think too Pearce's final paragraph is highly problematic. Climate change presents different challenges to species compared to most past alteration of the earth by humans. There is both the degree of change and the rate of change which are vastly greater compared to what has occurred for around the past ten million years. No doubt, nature will still be resilient but will likely show evidence of change not seen since the C–T event.

Finally, a question needs to be asked about the point of establishing that nature is resilient, if by that all we mean is that some species of plants and animals will return and re–establish. We already know nature is resilient, but what comes back might be very different. Does this matter? And as far as extinction are concerned each one removes evolutionary capital. The estimates of species and genotype loss from climate change are on a vastly different scale than things Peace mostly focuses, but he mostly ignores this.

Posted by Dr. John Lemons on 16 May 2013


Abstract from "The 'New Conservation’s' Surrender to Development" by Brian Miller, Michael E. Soulé, and John Terborgh:

When a functioning ecological system is perturbed by human activity, processes are distorted and species diversity often declines. Research has shown that loss of species diversity decreases productivity, resilience (stability), efficiency of ecosystems, and increases chances of catastrophic disease. Recently, powerful interests propose to manage wild places and biodiversity for human benefits alone. We argue that this ideological leap rests on several flawed assumptions: (1) nature is a warehouse for humans (2) humans can construct new ecosystems from non-native species (exotics) (3) humans don’t have to live within limits (4) nature is resilient (5) nature is nowhere pristine (6) nature is a social construct (7) conservationists preach too much doom and gloom (8) humans can manage nature intensively while preserving biodiversity. We contend that these revisionist anthropocentric doctrines are faith-based, resting more on an engineering world view and wishful thinking than on evidence.

I'll take Miller, Soulé and Terborgh over Pearce's gibberish any day.
Posted by Harry White on 17 May 2013


Industrial farming is just more profitable, meaning it cuts on labour force and drive people out of land and out of work. It is based on machinery and simplification which can by no means be compatible with an healthy ecosystem that relies on complexity.

It is less about subsidising small agriculture, for conservation, than stopping the flow of taxpayer money toward big farming. Besides it is proven, via leaks, that the American Administration is lobbying for GMO, using worker money to kill small farming all over the world. There is the problem: an administration owned by private interest.

In that light, we need to look afresh at conservation priorities. Novel ecosystems cannot be dismissed as degraded versions of proper ecosystems, nor can alien species be demonized simply for not belonging. If novelty and change is the norm, Hobbs and colleagues ask, does it make sense for the growing business of ecosystem restoration to try and recreate static historic ecosystems? By doing that, you are not creating a functioning ecosystem you are creating a museum exhibit that will require constant attention if it is to survive.

Posted by Anil Kumar Choudhary on 19 May 2013


As others have alluded, this piece does not meet the usual standards of most Environment360 articles.

Having taken a look at the Ellis papers cited by Mr. Pearce, it appears this article tends to overplay what the papers actually claim. Ellis’s global land-use analyses are broad scale modeling exercises, with the stated caveat that “the further back in time one extends the model, the poorer the data: In the ‘prehistorical period’(before 1700), all land use estimates depend on model-based reconstructions from limited sets of empirical data.”

I was surprised to read the author’s claim that a human impact on 20 percent of the earth’s land surface as of 5,000 years ago is a groundbreaking insight, given the global advent of agriculture is twice as old as that, and the widespread use of fire by indigenous peoples has been recognized by anthropologists and paleo-ecologists for decades.

To blithely claim invaded ecosystems are more biodiverse because they have more species, and “not necessarily worse” off is puzzling at best. The author apparently does not recognize that while local species richness might be increased by the invasion of generalist taxa, global diversity declines with loss of specialized local endemics. As Miller, Soulè, and Terborgh (cited above) say: “the trend is for increasing biological homogeneity, not diversity.” Biodiversity is not simply shorthand for species numbers; it comprises the full range of diversity, from genes to species to associations to biomes.

As for the “not necessarily worse off” claim, I invite Mr. Pearce to visit our Great Basin here in western North America, and witness the millions of acres transformed by the invasion of cheat grass and cows – an ecosystem once rich with native bunch-grasses, shrubs, and a diverse fauna, now transformed into a depauperate landscape, desolated by frequent fires and the loss of bird song.

And finally, to insinuate that ecosystems as super-organisms is a “conventional view,” is to ignore decades of work in disturbance ecology and conservation biology.

True Nature: Revising Ideas On What is Pristine and Wild is another voice arising from the so called “new environmentalism,” a growing chorus in which the author Emma Marris and Peter Kareiva of The Nature Conservancy are outspoken advocates. Their stated aim is to change the traditional conservationist view of people as guardians, to a view of people as gardeners. One of their chief targets is wilderness and other large natural areas protected from the worst of human impacts. Restraint is a term seldom seen in their writings. What they don’t seem to recognize is not only that their science is suspect, but more importantly, that the loss of wild nature is a profound and disheartening disaster to the spirit and soul of all people everywhere.

Posted by Tim Hogan on 22 May 2013


Three responses to this article. First, Pearce inter alia sets up a straw man for argumentation and makes generic claims about how “our” ideas of “untouched” and “pristine” are incorrect and thus require a revamping of conservation goals. What portion of the public is he talking about? I cannot identify any viable conservationist organization that is mesmerized by or otherwise entirely focused on “pristine.” There exists a widespread recognition that much of the Earth has been impacted by human beings in some way, but Pearce’s article perpetuates the straw man argument (made by Marris and her ilk) and thus makes the tacit suggestion that because there is no such thing as pristine, the justification to preserve or restore anything must necessarily change, or just go away altogether. “Nothing to see here folks.”

The 1964 Wilderness Act makes no requirement that land qualifying for designation be pristine. Many wilderness areas in the U.S. (Desolation, California, and Indian Peaks, Colorado, for example), and many national parks were once locations for a wide variety of human activities such as grazing, mining, and water management. These places are far from pristine, but nevertheless retain powerful elements of wilderness value that can and should be preserved. True, we need not endeavor to uproot every dandelion, but let’s not turn away from challenging conservation or rehabilitation efforts simply because we can’t bring ourselves to identify anything as pristine.

A second point relates to invasive species and Pearce’s claim “invaders swiftly settle down and become model eco-citizens.” It’s easy to cherry pick a case or two, but what about examples like the tamarisk in the American Southwest, Burmese pythons in the Everglades, cheat grass on the Great Plains, zebra mussels in the Great lakes, rats and goats on the Galapagos, or rabbits and cane toads in Australia? These are hardly model eco-citizens in light of irrefutable evidence about their destructive role in their new homes. Can anyone seriously argue that any of these species (and there are many other examples) are making a positive contribution to biodiversity? Have millions of dollars been spent on control or eradication efforts because these species are model eco-citizens?

Incidentally, while Hawaii may be considered by some to be more biodiverse today in terms of the sheer number of species on the islands, that isn’t necessarily a positive development as the
list of extinct and threatened native species indicates. The invaders have essentially wiped out a good portion of the natives. Leaning toward the shallow position that more species equates to greater biodiversity is a huge disservice to biological reality and especially to those species pushed to and over the brink of existence.

Finally, Pearce attempts to end his article on an upbeat note by claiming “the good news from all this is that nature emerges as resilient and adaptable, able to bounce back from the worst we can throw at it.” Is that right? What about the fate of wild Pacific salmon, desertification in
the Mediterranean Basin, suburban development across once productive farmlands, continued destruction of animal migration routes, plastic in the oceans, toxins in the bodies of marine (and other) mammals, or the fate of the Colorado River, just to name a few examples? Resilient and adaptable? Bouncing back? These claims are mostly baseless beyond a handful of select examples. One hopes the products mentioned as science in this article are neither mainstream, nor moving in that direction.

Posted by Kyle Gardner on 23 May 2013


Whether we embrace anthropogenic change, shrug it off, try to hold it at bay or strive to 'reverse' it, a few facts remain: it's happening at all scales, and there's probably no individual life on the planet that isn't being touched in ongoing ways. People are part of the real world everything lives in.

Some proximate effects in some places and on some species are roughly foreseeable. For the most part, though, we don't know and can't know in much detail what to expect. We are facing the effects of perhaps tens of billions of decisions and actions taken every day. Most are habitual or tactical and occur without reference to their potential cumulative or ultimate outcomes.

Experience to date indicates we really aren't smart or benevolent or organized enough to manage the biosphere, and not just for lack of information. Neither the wisest nor the most strident nor the most moderate voices can offer a comprehensive 'way out' of a predicament that is (culturally, at least) several thousand years in the making.

To those obsessing about 'invasive' species, I can only suggest that you think very carefully before complaining about things that are thriving under prevailing conditions, because they are the progenitors of the future. They are not bad actors. They are 'the fittest'. How they got that way doesn't matter, and never has. They owe neither allegiance nor consideration to others to futures or to pasts.

As always, individuals of all lineages will either survive or not, and populations of all taxa will persist or not under the conditions they actually encounter. Life will go on and evolution will continue until it can't. And as always, it will happen primarily moment by moment.

Posted by Matt Chew on 12 Jun 2013


There is absolutely nothing new in the finding that humans have had major impacts on nearly all of the Earth's environments over the hundreds of thousand years of their existence. What would be surprising if it was found they had not. All wilderness conservationists as far as I am aware acknowledge this. What they do claim is that if humans are deliberately left out of the equation (except as guardians) as far as active disturbance is concerned the forces of nature will come to be dominant. Of course for the maximum possible outcome relatively large wilderness areas are necessary. This is not to claim that there will not be human factors still at work (even in Antarctica) but they will minimised.

Posted by Geoff Mosley on 01 Jul 2013



 

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