BY STEVE URIE | Truckee
Over the past decade, academics, environmental engineers, and government agency managers have driven a public aquatic invasive species policy that has enlisted the consent and support of virtually every environmental organization, agency, and Tahoe citizen. Painted by Tahoe’s aquatic ecologists as evil invaders that must be repelled at all cost, all non-native aquatic plants and animals (except trout and salmon) are as popular at Lake Tahoe as pond scum.
Even though few non-native animals can survive, much less prosper, at Lake Tahoe, millions have been spent to prevent them from trying. And millions more are spent to monitor, control, and attempt to eliminate the hardy few who do find a niche in the lake’s ecology. The largest expenditure has been on the control of Asian clams. Ecologists agree the clams, which are also called pygmy clams and golden clams, will always be in Lake Tahoe, regardless of how much money is spent to eliminate them. None of the lake’s aquatic invasive species have been eradicated, nor has control resulted in their long-term reductions at Lake Tahoe or anywhere else.
Extensive control efforts are underway to reduce the established clam population, but evidence conclusively shows that the method of purging the lake of Asian clams is environmentally destructive. The rubber matting used to suffocate the clams sterilizes large portions of Tahoe’s sandy shoreline, killing native and non-native species alike.
To the April 2011 Lake Tahoe Aquatic Invasive Species Forum, Tahoe Environmental Research Center Director Geoffrey Schladow said, “You see death just about everywhere. One of the disadvantages of [the rubber mats] is that it takes out the good guys along with the bad guys.” The bad guys are, of course, Asian clams.
The good guys are at least a dozen other native aquatic plants and animals that live on the lake floor, including pea clams, which have lived in Lake Tahoe since long before any human viewed its grandeur. About the pea clams’ chances of surviving slow suffocation by rubber mats, Schladow says, “Some of the good guys like the pisidium [pea clam] will possibly survive” — or possibly not.
The Tahoe Regional Planning Agency takes Schladow’s nonchalance toward the natives a step further and justifies killing untold numbers of pea clams, saying, “Control actually gives the natives a leg up in the competition, even after killing some of them.” Unfortunately, no pea clams were available for comment.
Four years ago, Schladow told a UC Berkeley audience: “In one year’s time, Asian clams have changed from being virtually unnoticed to having an all-consuming presence.” And last October he said, “You’re laying down mats … so the shells aren’t affecting people.” Have you noticed the clams’ all-consuming presence or even seen an Asian clamshell, and if you did find one, wouldn’t the tiny shell be prized and slipped into a pocket?
Since his presentation, generalized statements such as Asian clams “affect the lake’s ecology, appearance, property values — everything,” has created an exaggerated sense of urgency that borders on hysteria, and 40 public and private organizations and agencies have stepped up to sponsor and support TERC’s work in controlling Asian clams before they “spread to an unmanageable level.”
This rhetoric has filtered into the national media, where outlets like UPI.com’s Science page reports, “the clams will consume so much plankton native fish will starve.” And by saying “Asian clams out-compete native species,” Tahoe ecologists imply there is a limited number of ecological niches that the lake supports, and that Asian clams are denying native species their rightful place.
This is not true. There is growing evidence that many non-native species improve biodiversity and strengthen some native species. The pea clam is only one of many victims in this Darwinian process that is being designed and accelerated by engineers. And when non-native species don’t cause problems, isn’t it preferable to allow nature to determine its balance instead of engineers?
There is great enthusiasm to see all non-natives, except sport fish, controlled in Lake Tahoe, but at what ecological and financial costs? (A request to Ted Thayer, TRPA’s Lake Tahoe AIS Program Coordinator, asking for this year’s TRPA AIS program budget was unanswered.) Is it worth killing a dozen good guys to get one supposed bad guy? And are Asian clams really Tahoe’s bad guys?
It was disheartening when Schladow told his Berkeley audience, “It will take a lot of money to reengineer the Basin.” Many believe Mother Nature did a magnificent job designing Tahoe, and that we should help salve her wounds by not indiscriminately killing the lake’s native plants and animals just because we’ve been prejudiced against a new one — who knows, five years from now Asian clams may be less intrusive than non-native crayfish and trout. It’s certain that pea clams already find them less invasive than humans.
~ Steve Urie is a graduate environmental engineer and a 40-year Truckee resident.
Editor’s Note: View this guest column online for links to the referenced studies, presentations, and media reports.
