Shifting Baselines

Captain John Smith
Monument to Captain John Smith, Jamestown, Virginia

In 1608 Captain John Smith led a crew of fourteen to explore the Chesapeake Bay in a shallop brought over from England in the hold of the Susan Constant.  Leaning over the side of the small craft they could see nearly four fathoms down through clear water. The bed of the estuary was encrusted with oyster reefs, enough to completely filter the bay every week, and some of the shells were large enough to serve a hearty meal. In his journal, Smith recorded, “the oysters lay as thick as stones … (there are) more sturgeon than could be devoured by dog or man … (and plenty of) grampus, porpoise, seals, stingrays, brits (?), mullets, white salmon (striped bass/ rockfish), trouts, soles, and three sorts of perch.”

The sailors must have been in awe of the bald cypress trees lining the shore like a curtain behind which a mysterious forest stretched to the horizon. The canopy was taller than any cathedral they knew in Europe, and was home to unfamiliar birds and game animals. Native people never went hungry where there was so much good fishing and hunting, and they grew corn, beans, and squash in the clearings. Smith noted the country was “very goodly.”

He never found the gold he came for, nor did he realize that the real wealth lay under his boat. It wouldn’t be harvested until the Oyster Rush in the 19th Century, which made shellfish a rarity. When they were still plentiful, their shells accumulated in the sediments leaving a record of when the Bay still teemed with life.

Fishermen and commercial watermen plowing the bay today are content with their normal catch of seafood because its original abundance stretches our imagination, if we think of it at all. We define what is normal not from the deep past, which is barely-known, but from our own experience and stories passed down by elders—“You should have seen the catches in my day, boy!” The pristine state of the Chesapeake Bay and its watershed predate human memory, and explorers like Captain Smith have left scanty records, if any. But does it really matter what the Bay looked like, because in a fast-moving world our attention is fastened on managing a man-made present and future? History is bunk, isn’t it?

Daniel Pauly disagrees. He has a theory that each generation makes its own mental map of what is normal, and consequently it can have lower expectations of richness and diversity in the environment than the previous generation if that has already deteriorated. Progressive generational myopia is called “shifting baselines,” and as a marine biologist Pauly had ocean fisheries in mind, although the concept applies generally in conservation biology and social science. To remind me of the concept I have a list of favorite shifting baselines, starting with shifting waistlines:

  • A Gallup Survey showed that Americans weigh 20 lb more than they did two decades ago, which many people thought was “just right” or normal.
  • House finches can be seen most days in Eastern Virginia, but that would not be normal for previous generations of birders.
  • Thin topsoil in my yard is normal, although I now know that a farm exhausted the land years ago when it was much richer.
  • Since average Americans watch live TV for 34 hours a week I presume they are satisfied with normal programs, though old curmudgeons who remember the hey-days of TV excoriate them.
  • Slow journeys to work in congested cities are not frustrating to everyone as we might expect because new residents accept lengthy commutes as normal.

You will have many more examples of your own, but I must get back to my theme.

There is no doubt that we have been poor stewards by polluting and overfishing the oceans. As consumers we feel the scarcity in our pockets from spiraling prices of tuna, cod, and anchovy, etc. That such a wonderful food is becoming only affordable in the rich world is a tragedy, and governments have been slow to protect collapsing fisheries, perhaps because conservation science has been blinded by the wrong baselines. Maybe a better knowledge of the original state of the environment can help to protect oceanic health and stabilize harvests because everything in a living ecosystem is linked with something else, like a spider’s web which is sensitive to changes in tension anywhere in its orb.

All things are connected.

Whatever befalls the earth

Befalls the sons of earth.

Man did not weave the web of life,

He is merely a strand in it.

Chief Seattle (1780-1866)

Chief Seattle
Chief Seattle

The wisdom of an old Native American chief who lived close to nature chimes with modern ecology. But how can we discover what stable and healthy environments looked like before they were exploited—from poring over the logs of old explorers, fishermen and whalers, or dredging up sub-fossil remains like oyster shells? The baselines that Captain Smith knew have been lost and there are precious few pristine places anymore to serve as models.

It was not however the sea but the land that alerted me to one of my own shifting baselines. I knew that most of our eastern forests are secondary or tertiary growths that have been rapidly regenerating since farming and logging started to decline here. But my error was to assume they were in the process of becoming facsimiles of the virgin forest and would again harbor the same native species with huge tree boles and towering canopies, as if we had never trammeled the land. And I thought the few remaining stands of uncut forest and reforested land protected by the Wilderness Act were pristine.

When President Lyndon Johnson signed the Act into law in 1964 he said something that used to strike a chord in me: “If future generations are to remember us with gratitude rather than contempt, we must leave them a glimpse of the world as it was in the beginning…” (emphasis added). I wish it could true, but regret I have been naïve.

I see many native trees and shrubs on my hikes that have seeded naturally—oaks, maples, hemlocks, et cetera. I fooled myself that the mixture is normal. I thought that wildness guaranteed the forest is the same as it was in the beginning, but in fact it is coming back differently. Some species that used to be dominant are now absent and replaced by foreign species. Suppression of natural wildfires (a well-meaning forestry policy) encourages the succession of fire-resistant species by others, and firebreaks create more edges where different species thrive. A history of logging and poor farming practices has often exhausted or eroded the soil, and dams and mills have altered floodplains and sediments which, in turn, alter the vegetation that grows there.

The American chestnut tree was my biggest blind spot. The tree used to inspire country folk to dub it “king of the forest,” but it is completely eliminated by blight (American Chestnut: the Life, Death, and Rebirth of a Perfect Tree by Susan Freinkel). There is now a host of introduced diseases and insect borers working their way through our pines, oak, hemlock, ash, and dogwood, and they are very hard to control. Sometimes alien species out-compete the native flora because grazing beasts and insects in their new country find them unappetizing.

George Washington
George Washington by Gilbert Stuart

If we could resurrect Captain Smith from his London grave he would tell us tales of a primeval forest he knew that is very different today. We have inklings of it from archives of the colonial era when land surveyors like a young man called George Washington were drawing plats in Virginia’s western frontier for farmers, lumbermen, and land speculators. “Witness” trees that were used as boundary markers on plats give a rare glimpse of species that grew there over two centuries ago.

land plat
A land survey plat by George Washington

And in the North-East and Appalachia sub-fossil records show that giant beech, hemlock, and spruce of the old-growth forests are now substantially replaced by maples in regenerating forests. This difference may not seem unwelcome because maples are ornamental natives, but they are less productive for supporting animal communities and the farm animals that used to run in the forest. The most productive species of all, the oak family, has declined across the range.

Gaudineer Scenic Area in West Virginia. A tiny fragment of uncut, old-growth Appalachian forest

I know that it is no good fawning over the old forests, whatever they were actually like, because they will never come back. Looking back at their green light is unlikely to make a difference, and it is futile to “beat on, boats against the current, borne back ceaselessly into the past (The Great Gatsby). The land passed a tipping point of no return a long time ago when drivers of change were first released into the environment, and they continue to mold it. These changes may even accelerate with global warming.

But if the land is slipping further away from its original state, we can be more optimistic about oceans according to marine biologists. Some of them say the tide of ocean poverty can still be turned by careful management, and the Chesapeake Bay is improving, if agonizingly slowly. For eons, the Bay danced only to nature’s tune, rolling with the seasons, and generations of Native Americans who had little impact on it therefore shared a mental baseline for what they thought was normal for its waters and in the surrounding forest. Only when European colonists arrived with technologies for rapidly extracting resources was there much change, and after four centuries of exploitation Captain Smith would find the Bay strange and much diminished.

I was musing that we condemn people responsible for war, prejudice, and human bondage but rarely blame those who have spoiled the environment by industrialization, mining, overfishing, clear-cutting, and draining, eroding and poisoning land. I wondered if we excuse the pioneers because they struggled to survive in hostile territory and perhaps felt a God-given right to subdue it? Or was it because as their power of exploitation grew they didn’t realize the sea and land have limited abilities to recover? Or do we forgive them because we have benefited from their excesses. Perhaps it is a bit of all of them, but those who don’t know better can’t be held responsible for error.

I then wondered if the excuse is wearing thin on current generations and if we will be judged more harshly than we judged the past. We are no longer ignorant of our impact and are leaving plenty of evidence of our own stewardship. If future generations live in a more impoverished world than ours they will not be so blinded by shifting baselines and would justly hold us in contempt, just as President Johnson warned.

Next Post: Scavengers and Decomposers

Green Fire

“We reached the old wolf in time to watch a fierce green fire dying in her eyes. I realized then, and have known ever since, that there was something new to me in those eyes—something known only to her and to the mountain. I was young then, and full of trigger-itch; I thought that because fewer wolves meant more deer, that no wolves would mean hunters’ paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view” (Aldo Leopold, A Sand County Almanac, 1949).gray wolf

As a forester in the South-West, Leopold’s job was to control predators for protecting game species.  But one day after shooting a wolf he had something like a religious conversion experience: an ineffable change of heart. He started questioning policies and cherished beliefs about managing wildlife populations. He guessed that when wolves and cougars were extirpated the deer and elk populations would boom, the genetic stock would deteriorate as less fit animals were no longer weeded out, and overgrazing herds could eat out their food supply and starve. He had realized that when a keystone species is eliminated the ecosystem gets out of whack, although he didn’t live to see proof of his theory when gray wolves were reintroduced to the Yellowstone National Park.

Leopold, exchanging his rifle for a pen, drafted a Land Ethic from his Wisconsin farm at the end of life. When I read the passage that, “conservation is a state of harmony between men and land,” I wondered about my own backyard.  Is it as harmonious as I assumed, or had I been hardening an ecologically dissonant landscape?

After a hurricane ravaged our acreage we brought in topsoil, planted trees, seeded lawns, and laid out flowerbeds. It was patient work and now, nearly a decade later, the yard looks mature and the new growth provides welcome shade from Virginia’s summer sun. A landscape designer planned the attractive setting for our home, something that neighbors and visitors could admire and I could imagine featuring in a glossy garden magazine. But in making landscape appeal the goal we paid no heed to the interests of critters who shared the land with us. Perhaps I was delusional in thinking I was acting as nature’s physician, healing the wounded land by turning it into a garden of neat lawns and cheerful flowers. I know how appearances can be deceptive, like assuming that a ruddy human face always means a healthy body.

Energy pyramid
Energy pyramid

Healthy bodies don’t need a physician because they can fight off some threats and repair wounds.  We have allostatic mechanisms that return stressed bodies to a stable state. Likewise in the oak-hickory forests that existed here before European colonization, there was a self-regulating biome in which the bottom of an energy pyramid fed by products of decomposition and photosynthesis provided nourishment for a rich variety of herbivorous animals which, in turn, fed carnivores and top predators. After a wildfire or storm the landscape was gradually restored by a succession of larger plants and trees, like scabs healing over a skin wound until the canopy closed over again. When Teddy Roosevelt wrote about the Grand Canyon, “You cannot improve on it. The ages have been at work on it, and man can only mar it,” he might have been thinking about the great eastern forest of America, but it was already fragmented. It had taken only a few generations to undo what eons of evolution had created.

A land as bountiful as Virginia’s was never going to be left to nature. The Peninsula is now a mosaic of farms, gardens, and woodlots. It is picturesque, even romantic (Virginia is for Lovers), but no longer in harmony with nature. Even nature preserves that look “natural” to our eyes need help in their struggle against invasive animals, plants, and diseases introduced from Asia and Europe: bamboo marches, kudzu smothers, cankers kill, and Japanese stiltgrass blankets the forest floor. Gardeners and farmers wage incessant war on alien plants and epidemics of tent caterpillars, Japanese beetles, ticks, and cloven-hooved locusts (deer).

kudzu vines

Despite spraying lakes of herbicides and pesticides, the insurgents keep coming back. In trying to dominate nature and grow for our own needs and pleasure we are eliminating, often unintentionally, some critters at the top of the pyramid that are most beneficial as pest consumers (birds, bats, amphibians, and reptiles) or control deer herds (wolves). At the bottom of the pyramid our impact is mostly feeble or temporary (invasive and disease-bearing plants, fungi, and microbes). We would like to turn the pyramid on its head, but that is biologically impossible. Being mainly an urban species now, most of us are unaware of how much havoc human ecology has created and our continuing dependence on nature.  Some species of formerly common birds have declined by over two-thirds since the 1960s; many butterflies and bumble bees that do magisterial pollination services are vanishing; forty years ago you had to raise your voice to be heard here above the din of crooning frogs, but no longer. Poisons and starvation are depleting the landscape of wonderful creatures and some of our best friends.

Japanese stiltgrass
Japanese stiltgrass is even eschewed by deer

Before I read Leopold’s book I was already tapering off my use of chemicals in the yard, applying Roundup only for spot treatment of weeds. But now I realize that my change of heart was far too tepid, and that pretty flower borders and lawns look like sterile deserts to the critters who used to live here. Most of the plants we buy are aliens that evolved in quite different environments, and without their natural herbivores they grow profusely, sometimes out-competing the natives.

If these foreigners are unpalatable to caterpillars and grubs it would explain why butterflies, bugs, and creepy-crawlies are so much diminished, except for the hardiest ones which can boom when they have fewer competitors and predators. To test this hunch I checked if insects prefer our native plants.

I collected bundles of leaves from many different species in our yard to count the percentage that had been nibbled. This wasn’t a perfect study, but I didn’t need more data to convince me that natives (green color) were the preferred food plants by a huge margin. Most aliens (red) were ignored by the diners.

leaf survey
Leaves nibbled by insects

I shouldn’t have been surprised. Apart from a few insects that are not fussy about their veggies, most are particular about their food plant which they are adapted to chew and digest because they evolved in the same habitat. We have provided an inedible landscape.


Animals can adapt to graze a species that is new to them, but require thousands of generations. Take for instance phragmites (“phrag”), an aggressive reed that is overrunning wetlands and shorelines up and down the East Coast. In its homeland on the other side of the globe it is a food plant for 170 species of herbivores of all kinds, but since it was introduced to North America three centuries ago there are still only five species that will eat it. The mill of evolution grinds slowly.

Doug Tallamy’s book helped to bring home these thoughts (Bringing Nature Home). He is an ecologist at the University of Delaware whose vision is a garden revolution for a more sustainable relationship with nature. It is too late to preserve more wilderness areas here, but there are lots of “spare” land in backyards, and 40 million acres of lawn in the US. He urges us to cast aside esthetic preferences to cultivate more native plants.

This doesn’t mean turning back the clock to the original forest—which has gone forever. But we can have a healthier land, and need it as desperately as a patient fed by tubes, wires, and drips in the ICU needs organ and stem cell transplants to recover.

But when Tallamy explained that native plants help to restore the numbers of insects I paused.

Yikes! Is he crazy? What will my family and neighbors say?

“Don’t we have enough bugs already, Roger?” I hear someone say. “Remember the yellow jackets that chased me inside? And didn’t you complain about horseflies?”

“Yes, dear.”

It’s hard to defend bugs and creepy-crawlies, apart from butterflies and bees. It’s easy to point fingers at industries that pollute waterways and developers that scorch the ground for new shopping malls. But responsibility also rests on our shoulders, and especially gardeners and farmers as land stewards.

With a pricked conscience I raised my lawnmower blades to their maximum height so that white clover flowers beloved by pollinators are not decapitated. I’m now convinced that clover is more attractive than fescue, staying green all winter, and more beneficial, providing soil nourishment by nitrogen-fixation in the roots. Clover is not a native here, but I’ve found commercial growers that supply native plants for a butterfly garden: milkweed for monarchs, spicebush for swallowtails, and violets for fritillaries. I also have a new “immigration control” policy for alien plants, and am growing native redbud, dogwood, crab apple, Rudbeckia, sneezeweed, joe pye weed, wild asters, and possumhaw. They are no less beautiful, and if their leaves are grazed more by insects I feel a green fire of satisfaction that critters will feast on them.

Next Post: Re-baselining

The Return of the Native

Blogger_at-workApologies to anyone who recently visited my blogs posted between January and March 2013 and found the pictures were missing. This was a widespread problem affecting WordPress bloggers, but the images have now been reloaded.


A large black-and-white bird flying above our yard towards the James River caught my eye last week. It was no “buzzard.” A bald eagle is still uncommon enough to be arresting, and perhaps there is even a patriotic American somewhere who stands to attention when he sees his national emblem soaring past, like Air Force One. But there is a grander reason for saluting the bird—it is a native that has returned home.

Eagles were a common sight in the Chesapeake Bay watershed until catastrophes in the 1950s and ‘60s. In those decades, an industrial plant was disgorging poisons into the James River. The chemical waste was Kepone, an insecticide related to DDT, which so polluted the river that a Virginia Governor prohibited consumption of fish for a 100 mile stretch. But no respecters of law, eagles kept fishing. Not only did they accumulate poison from eating fish but also lead from the scattered gunshot of duck hunters. Hardly a single chick could be brooded in those days. Those woes were aggravated by the loss of nest sites to waterfront developments, and the failure of naïve birds to navigate around traffic and power lines. It seemed as if the 1940 Act of Congress intended to protect the species had been written on disappearing ink.

Photo: Don Snyder

Forty years ago you would have been lucky to have seen a single eagle along the James; fewer than thirty pairs nested across the entire state. But after the poisons were banned by the EPA in 1972 river health slowly improved, which encouraged the US Fish and Wildlife Service to launch a program for reintroducing eagles. It is perhaps the greatest American conservation story for a single species. Nest sites are monitored annually by fly-overs in light aircraft, and at the last count there were over 700 breeding pairs in the state, allowing the species to be delisted from the Endangered Species Act. So the bird depicted on the escutcheon of the Great Seal of the United States can now be seen even within Washington DC itself, and that is something that even congressmen who put business before conservation should be proud of! 

On that eagle day, my mind was pulled away from its absorbing interest to thoughts that had no obvious connection.  I found myself thinking about Clym Yeobright in Thomas Hardy’s The Return of the Native. When an image comes out of the blue like that I often strain to find a meaning for the unexpected distraction. I suppose there was something inside me trying to fathom a metaphor for what I had just seen.

Clym Yeobright and his wife Eustacia in The Return of the Native

In the novel, Clym returned to his birthplace on Egdon Heath after making his fortune in Paris. It had been hard growing up on the Heath, but he believed it would be easier now to flourish in the bosom of land that had nurtured his ancestors, where old neighbors would celebrate his return and he could settle down to productive work with a wife and family.

Perhaps the novel came to mind because I was uneasy remembering how things turned out for the returning native and deep down was wondering about the fortunes of eagles back in their homeland. But unlike Clym, who needed no help moving to the Heath, bringing species back often needs our helping hands, the very hands that originally extirpated them. The job of preserving species seems unfathomably difficult to me, and is yet so immensely important for preserving the web of life and a healthy planet, which some call Gaia. But since human populations are continuing to migrate from rural origins to urban communities it is easy to forget our dependence on biodiversity. Connections between sources of our food, clothing, medicines, and raw materials for manufacturing and building on the one hand and living things “out there” on the other are under-rated or taken for granted. Without beloved companion animals inner city dwellers might even forget that we share the planet with other creatures. And when we do think of human ecology we find it overwhelming and hope that someone else is working on it.

The United Nations has designated our times as a Decade of Biodiversity. It is an admirable attempt to draw global attention to environmental sickness, even if the politicians themselves are soon distracted by the latest humanitarian disaster (caring for the one species instead of for all). Unfortunately, no one I asked had ever heard about this splendid declaration—nor had I before preparing this post—but the responsibility for preserving biodiversity really should fall on our shoulders, and the efforts of government, NGOs, researchers, and citizen scientists need our support.

Since zoos, wildlife parks, and technology can only go so far towards preserving species, rare animals and plants must eventually be reintroduced to their old habitats. The international organization that reports population status and coordinates reintroduction programs is the IUCN. It publishes the famous Red List of species that are threatened or endangered, including those that are extinct. A Threatened species is one that is vulnerable to stepping down the list to Endangered, the dire category which used to include bald eagles. Searching the List for threatened species is quite sobering because it includes 41% of all amphibians, 34% of conifers, 33% of corals, 31% of sharks and rays, 25% of mammals, and 13% of birds around the world. Diners are relieved that most types of lobster are safe, at least for now (1%).

When humans become urbanized the disconnection with nature makes it harder to notice or even care about year-on-year changes in the natural environment or that a formerly abundant species has now grown scarce. Like the drip-drip of a retreating glacier, it is only by observing over a period of time that you notice how far it has retreated up the mountain. At least that is how I rationalize the gap between my impression that songbirds are as common as ever in my backyard and the fact that national bird counts reveal alarming trends over my lifetime.

It is a sad reflection on the character of Homo economus that both the UN and conservationists feel it is necessary to appeal to our self-interest to encourage conservation-mindedness. One of their favorite examples is the Amazon jungle, for which preservation is sought for the cornucopia of potentially valuable products and medical remedies for ourselves. Perhaps we would feel more concerned if we lived five times longer than our four score years, since we would then have to face a more impoverished landscape in our own lifetime. But for me the moral argument is so much more powerful: that if we live more gently with nature we can avoid the curse of posterity for grandstanding and being grand executioners during the sixth great extinction on earth. This is the only extinction we cannot blame on geology or asteroids.

If the resources available for research and conservation were stretched thinly enough to cover most threatened species nothing could be achieved, so hard choices have been made. Those getting most attention are well-loved or iconic species, and many of them sit at the top of the food chain, like eagles. Golden lion tamarins (Brazil), Siberian tigers (Asia), black-footed ferrets (Great Plains), and gray wolves (Yellowstone National Park) have been successfully reintroduced, and the publicity helps to prime the pump for funding other projects. But what about more lowly species that are nevertheless important for supporting those above them in the chain? Who is going to help half-a-million species of beetles?  The physiologist J.B.S. Haldane pointed out that God must have had “an inordinate fondness” for them, so surely they deserve some attention?

I have a particular fondness for the red kite story because forty years ago I drove with student friends to Tregaron Bog in mid-Wales to see the last survivors in Britain. Before persecution they thrived throughout the country where they provided equivalent services to vultures in other countries. We only had a fleeting glimpse of two rusty-colored raptors with forked tails as they flew over the wetland, but this was enough to tick them on our checklists, as crazy birders do, before turning for the long journey home. We anticipated their imminent extinction, but some years later healthy birds were brought over from Europe to found a thriving population now numbering about 2,000 pairs. The bird has been seen again in London and hunts the countryside of Hardy’s Wessex novels.

Yet behind these sweet stories eternal vigilance is needed as the price of biodiversity, to twist an expression often attributed to Thomas Jefferson. Habitats are not static, human pressures come and go and come again, and the globe continues to warm, encouraging competitive alien species, melting ice shelves under polar bears, et cetera. Besides, not everyone welcomes the natives home. Developers grumble that people should have a greater call on waterfront properties than eagles, ranchers in Wyoming and Idaho keep their guns handy watching for wolves, and an English student even complained that a red kite had swooped down for his sandwich! Restoring species to their habitats is patient work, and never ending.

That brings me back to Thomas Hardy who, as a Victorian, was lucky not to live in such anxious times. Life didn’t turn out well for Clym, the returning native. He never settled down happily and found himself at odds with residents and married a belle who became dissatisfied after he fell into poverty, working as a laborer cutting furze on the cruel Heath.

I always hope that after suffering trials sympathetic characters in the novels I read will be rewarded with a contented and harmonious life, but that never happens in the Hardy world where fate trumps hope. The author may have called himself a realist, but pessimism is an unattractive demeanor that curbs endeavor and can be a self-fulfilling prophecy. I wish it had been Jane Austen who had come to mind on my eagle day because Jane-AustenDarcy returned to Longbourne to marry Elizabeth Bennet and they lived happily ever after, and that is the metaphor I wish for all returning natives.

New Post: Bugs need not Apologize