Sand County Revisited
by Dan Whipple
Aldo Leopold wasn't just "an American Isaiah" writing an "almost holy book in conservation circles," as Wallace Stegner wrote, referring to A Sand County Almanac. Leopold was also a practical farmer and a scientist. Now, 50 years after the publication of his landmark book, Leopold's legacy is being used to illustrate the effects of climate change.
As Aldo Leopold restored the Wisconsin farm that provided the inspiration for his land ethic, he kept a record of the farm's inhabitants. From 1936 until 1947, Leopold recorded the spring arrival of birds and the blossoming of plants. In 1976 Nina Leopold Bradley, Aldo's daughter and a plant ecologist, moved back out to the Leopold Preserve to continue her father's work. Since then she has kept similar records.
The records show that global warming is changing the very mark of spring. Bradley tracks 300 different natural events--mostly the timing of birds' and plants' natural cycles. "We are finding that at least a third of the [events] are happening earlier because of the warming temperatures," she says.
Other scientists are finding similar trends around the globe. A study by Camille Parmesan, an entomologist at the University of Texas at Austin, concluded that the checkerspot butterfly has shifted its U.S. range northward in response to warmer temperatures, and that 36 European species have seen northward shifts in their ranges as well. She points out that many studies looking at the effects of a warming climate are short-term. "Only a few go back more than 20 years," she says. "The Bradley-Leopold study, with data going back to 1936, is exactly what we need. It tells you better whether it's an overall trend."
Bradley, along with her brother Carl Leopold and two other researchers, focused on 55 spring events, and found that a third of the events are occurring as if spring were arriving earlier. The Eastern phoebe, for example, is returning to the farm about 20 days earlier than it used to. And the forest phlox is blooming in late April instead of mid-May. Birds migrating from central Mexico and Florida are returning as much as three weeks ahead of their usual time.
While some species of birds and plants are adapting to the changes in temperature by altering their habits, others are not. When the non-adapters do return they might find the best nesting sites already taken by the earlier arrivals, which could reduce their reproductive success. Plus, less food might be available. Carl Leopold fears that over time those species that are unable to adapt may be more vulnerable to extinction.
Marine Habitat: Scraping Bottom
Nestled at the foot of the Rockies, Colorado Springs doesn't have a whole lot of oceanfront property. So it's a bit surprising that Rep. Joel Hefley (R-CO) is sponsoring a bill to protect marine habitat hundreds of miles away. But last spring, when this avid sportfisherman read an article in his local paper about the devastating effects of trawling, he knew he had found his next project. "Even people in the Rocky Mountain West, who don't see much water, still have concerns about the world's oceans," Hefley says.
Hefley has proposed a moratorium on the use of trawling equipment at 16 spots off the coasts of Oregon, California, New England, and Florida until the National Marine Fisheries Service (NMFS) can determine the extent of the destruction such gear causes. Seabed-hugging trawl nets are a devastatingly efficient way to scoop up groundfish, shrimp, scallops, and other shellfish. When these heavily weighted nets, which are as much as 100 feet wide, are dragged along the muddy sea floor, they churn up, crush, bury, or kill everything in their path, including coral reefs, rocky shoals, and seagrass beds. Not only do commercially important species suffer, but other creatures do, too, including squishy sea cucumbers, sedentary tube worms, and spiny urchins. And once an area is trawled, it can't begin to recover, because it will be repeatedly trawled. Even if left alone, scientists project, it will take decades or even centuries for these natural structures to recover.
University of Maine oceanographer Les Watling estimates that trawlers scrape nearly 6 million square miles of ocean each year. That's an area almost twice the size of the continental United States, or 150 times the amount of forest clear-cut worldwide each year. "Just about all continental shelves are trawled," he says. Trawling is even allowed in most national marine sanctuaries.
Now's the time to address the trawling issue, Hefley says, since the Magnuson-Stevens Act is up for renewal this year. The act requires the NMFS to protect fish habitat, but the service has done little to regulate trawling. Although Hefley's bill has a ways to go--it's currently being evaluated by the Congressional Resources Committee and has half a dozen cosponsors--this bipartisan legislation is "the first to specifically address damage caused by trawling," says Elliott Norse, president of the Marine Conservation Biology Institute. "It's the first crucial step."
--Gretel H. Schueller
Of Mice and Men, and Women
Biologists have found some very strange rodents near northern California's Kesterson Reservoir--the same area where toxic agricultural runoff poisoned thousands of birds in the early 1980s. During routine wildlife monitoring, scientists discovered that one-third of the 87 mice and voles they trapped appeared to have both male and female reproductive organs. "The number of intersex mammals we found was surprising," says Michael Delamore of the U.S. Bureau of Reclamation. "What we've deduced is that if it occurred across four species, it was probably caused by some kind of environmental exposure." Researchers are using cellular tests to confirm the presence of both testes and ovaries. Next they will try to identify the cause and scope of the problem. It clearly gives them pause. "These are mammals--not so much different from you and me," says Delamore.
Fresh water is becoming an increasingly precious resource as the number of people living in water-poor areas grows. By 2025 as much as two-thirds of the world's population will face chronic shortages, according to the United Nations. "The wars of the next century will be about water," declares Ismail Serageldin, vice-president of the World Bank.
Representative Bart Stupak (D-MI) is leading the effort in Congress to block water exports from the Great Lakes and elsewhere in the United States. He is sponsoring a bill that would ban removals from any U.S. freshwater body until Congress sets rules and regulations to cover the practice. Stupak's bipartisan bill has 24 cosponsors, including 7 Republicans, and has won the backing of the Clinton administration.
Meanwhile, the Canadian government is urging its provinces to ban large-scale exports. Two years ago Ontario decided to allow a local company to remove 156 million gallons of Lake Superior water every year for five years for export to Asia. Though the amount was small--Buffalo, New York, uses about that much every three days--in May the province bowed to public pressure and reversed the decision.
Opponents fear that such a plan would set a dangerous precedent. "Where do you draw the line?" Stupiak asks. The Lake Superior scheme appears to result from flexible laws under the North American Free Trade Agreement, which seems to treat bulk fresh water as a "tradable" commodity, though these provisions have yet to be tested in court. Meanwhile, entrepreneurs are hatching thirst-quenching plans. The Global Water Corporation, in Vancouver, British Columbia, has received a permit from the city of Sitka, Alaska, to export up to 5 billion gallons per year from an Alaskan lake.
In August the International Joint Commission, which helps the United States and Canada resolve boundary issues, released a preliminary report on bulk removals. It noted that water in the Great Lakes system preserves environmental diversity by inundating dry areas and renewing habitat. Says Michael J. Donahue, executive director of the Great Lakes Commission, "Overseas water export is tantamount to draining this region's lifeblood."
As the nation's endangered-species capital, Hawaii is struggling to prevent new extinctions among its native birds. Exotic species and habitat loss have taken a toll, especially on the puaiohi, a small thrush found only in Kauai's AlakaŽi Wilderness Preserve.
In January 1999, 14 captive-raised puaiohi were released there [see "Born to Be Wild," January-February 1999], and researchers are eager to see if the rainforest songbird displays the same fecundity that marked its first breeding season in the wild. A federal Biological Resources Division crew tracked eight of the birds through the breeding season. Between March and September, the puaiohi produced 21 nests and 7 fledglings. Three of the females even paired with wild males. But rats managed to kill five nestlings and two adult females, despite intensive baiting and trapping. Still, enough survived to warrant the release of five more birds last month and to bolster hopes of creating a self-sustaining population.
What's New, Pussycat, Em-bry-o-o-o
Scientists are trumpeting the birth of Jazz, a rare African wildcat, last November. The reason: Her mother is an ordinary American house cat. Jazz, who was born at the Audubon Institute's Center for Research of Endangered Species (no relation to the National Audubon Society) in New Orleans, is the result of the world's first successful interspecies frozen-embryo transfer. Combining sperm from a male African wildcat and the egg of a female wildcat, scientists grew the embryo in an incubator for five days and then froze it. Jazz was born about 70 days after the thawed embryo was implanted in the house cat. The similarity in the size and weight of the two species makes them ideal for interspecies embryo transfers. Researchers at the institute are at work on similar projects involving tigers, lions, and bongos, an African antelope. Betsy Dresser, the project's lead scientist, is excited but doesn't want the new technology to be seen as a substitute for conservation. "The science is a safety net," she says. "It's just another tool to help insure against extinction."
© 2000 NASI