Tag: science

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 19^th 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)

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.

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.

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.

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