About thirty years ago, Paul Ehrlich began a book with an image that remains in my mind still: You are sitting on a plane. Outside, on the wing, you see a worker removing rivets. You watch one get popped out, and don't react. Then another...and another...At what point do you become convinced that the plane is unstable and you should leave?
The last baiji (Lipotes vexillifer or Chinese river dolphin) is probably gone. (The immediate cause--fishing with illegal longlines and giant hooks.) It follows giant mammals like Stellar's sea cow, Caribbean monk seal, and Japanese sea lion into oblivion. Most people you meet at the 7-11 will never have seen or even heard of any of these animals.
There are fewer than 300 jiangzhu (Neophocaena phocaenoides aseiaorientalis or Chinese river pig) left. Will anyone care if they disappear along with the whales, the sea lions, and the dugong?
It's hard to convince the guys you meet at the 7-11 that the disappearance of rare animals affects them personally. Many people believe that the largest mammals are just icing on the ecosystem cake--with niches analogous to that of humans, expendible in the overall food web. Part of that is due to simplistic ecology education at the K-12 level; cute, cuddly animals and bright green plants attached to one another in yarn chains. With more time and understanding, these "page 10" news blurbs would be a lot more frightening.
The newest research has confirmed that it's often the largest mammals that are the keystone species, ensuring the health of the ecosystem. Think of it this way: There are a variety of plant eaters in an area. One is stronger, reproduces faster. It could actually take over if allowed. But a predator keeps that bully under control. The plant eaters remain balanced. The plants grow. Without a single top predator, the whole ecosystem goes awry.
So you say to the North Dakota rancher, "You need those wolves. Without them, the prairie dogs will go crazy and make your ranchland look like Swiss cheese..."
Or to the Illinois corn farmer: "Have you thanked a black snake today for controlling your mouse population?"
Chances are you'll get the same incredulous disbelief with which most people greeted the news that the Bush administration was willing to list the polar bear as endangered. After all, there are over 20,000 of them, aren't there? And you aren't likely to run into one next week.
But the chain of life is long and complex, and could reach out and touch us far south of the bear's normal habitat.
First, why are bears disappearing? The most obvious cause, of course, is global warming.
Polar bears use sea ice for virtually all of their essential behaviors including feeding, mating, travel, and maternity denning. They cannot survive the loss of sea ice habitat that will occur if current levels of greenhouse gas emissions continue. Scientists have already recorded thinner bears, lower female reproductive rates, and reduced juvenile survival in the Western Hudson Bay polar bear population in Canada, which is at the southern edge of the species’ range and the first to suffer impacts from global warming.
Bears live most of the year as solitary hunters, and only seek out mates during estrous, so a decrease in density over their vast range could be a disaster for frustrated bears. The reaction of administration officials indicated a realization that the population could pitch faster than the passenger pigeon in the very near future.
So who cares about the bear? Well, follow the bouncing ball. Polar bears normally eat seals--ringed and bearded seals by preference, harbour seals and walrus in a pinch. Changes in the populations of their prey will lead to changes in populations of commercial fish, already shaky. Skinny, stressed bears are more likely to carry disease. Since they wander, those diseases can spread to domestic animals and even people. Bears, seals and fish may not be on your menu, but they are important to some populations, so their disappearance will stress other sources of food.
The ball bounces on...The truth is, we don't know where it will end up. Changes in the Arctic will reverberate southward, in ways ecologists can only guess.
The greatest challenge now is to implement the appropriate studies and infrastructure within the Arctic to monitor and document the sensitive linkages and the ecosystem responses...with a multi-disciplinary approach.
And that will take money and more concerned scientists...in an atmosphere where science is under attack from all fronts, and we are flushing money away in Iraq that should be used for science, health and education.
Our challenge in 2007--to get the guys at the 7-11 to "look out the window"--or to use Erlich's analogy, to get them to realize that each rivet we take out of the ship that is Earth endangers us all.