Monday, May 28, 2012

Zoos and Endangered Species -- trade-offs in everything

Take a look at this article by Leslie Kaufman for the New York Times, "Zoos’ Bitter Choice: To Save Some Species, Letting Others Die." An excerpt:
As the number of species at risk of extinction soars, zoos are increasingly being called upon to rescue and sustain animals, and not just for marquee breeds like pandas and rhinos but also for all manner of mammals, frogs, birds and insects whose populations are suddenly crashing.
To conserve animals effectively, however, zoo officials have concluded that they must winnow species in their care and devote more resources to a chosen few. The result is that zookeepers, usually animal lovers to the core, are increasingly being pressed into making cold calculations about which animals are the most crucial to save. Some days, the burden feels less like Noah building an ark and more like Schindler making a list.
A core dilemma is whether zoos should be more focused on entertainment, which people are more willing to pay for, or on preserving biological diversity for the "public good."

In some cases, it seems like advocates in the latter camp are more concerned with shaping public preferences than responding to them. The article continues:
Zoos are essentially given a menu of endangered species that the association is trying to maintain and can then choose according to their particular needs. But final decisions are often as much about heart as logic.
St. Louis, for example, has committed $20 million — or the equivalent of 40 percent of its annual operating budget — to building an enormous exhibit for polar bears — complete with a fake ice floe — even though its last polar bear died in 2009 and the Marine Mammal Protection Act makes it illegal to remove or rescue the bears from the wild. The zoo hopes that in the five years needed to open the exhibit, it can argue for an exemption, import orphaned bears from Canada or perhaps secure the cubs of captive bears.
Dr. Bonner acknowledges that the polar bear project runs counter to many of his more practical convictions on the role of the modern zoo. He has insisted that his keepers spend what limited field conservation dollars they raise on threatened animals that are most likely to make a comeback in the wild. With sea ice disappearing at an alarming rate, polar bears do not fit the profile.
But he justifies the exemption as a lesson for zoo visitors: “I want people to see this beautiful creature and ask, ‘How could we have let this happen?’ ”
Personally, if I went to a public zoo and saw nearly half of its operating budget spent on an object lesson in how difficult it is to preserve polar bears, collective guilt over habitat loss would not be the first thought to cross my mind.

There is a valid argument to be made for preserving biological diversity. Fear of a catastrophic breakdown, expressed through a variety of vivid analogies, is one of the more popular arguments, although perhaps one of the less valid. This "invisible threshold" argument has become a rationale for preserving species within even the most marginal ecological niches.
Several large buckets of dirt are now home to the threatened American burying beetle, so named because it buries the corpses of small animals, like birds and squirrels, and lays its eggs around them. Once, the beetles, with their brilliant red markings, ranged over 35 states. By the time the United States Fish and Wildlife Service listed them as endangered in 1989, there was one known population left, in Rhode Island.
At the government’s behest, the St. Louis Zoo, in conjunction with a zoo in Rhode Island, has been successfully breeding them and returning them to the wild.
Mr. Merz says the effort was worthwhile because the beetle might play an irreplaceable role in the ecological web. He considers picking species worth saving akin to life-or-death gambling. “It is like looking out the window of an airplane and seeing the rivets in the wing,” he said. “You can probably lose a few, but you don’t know how many, and you really don’t want to find out.”
One has to wonder, if burying beetles and partula snails are so crucial to the ecosystem, why are they only surviving in the back closet of a zoo? The burying beetle has functionally vanished from the North American ecosystem for over twenty years. Why haven't we seen any consequences yet?

Of course maybe this is just one more "rivet in the airplane's wing", the loss of which pushes us imperceptibly closer to global disaster. But, when you have to compare the costs of saving potentially millions of different endangered species, it helps to have an idea of the probabilities, rather than saying they are all equally unknown and potentially deadly.

What is the chance that any one particular species is completely irreplaceable? It is incumbent on the defenders of biodiversity to make these estimations, instead of demanding that every species must be saved, regardless of the cost. Even zoo-keepers can't live up to such an unattainable goal.

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