Conservation // Current

It’s Survival of the Weak and Scrawny: Researchers see 'evolution in reverse' due to Hunting

This article will make people think twice about the myth that hunting helps animals and conservation:

It’s Survival of the Weak and Scrawny

Researchers see 'evolution in reverse' as hunters kill off prized animals with the biggest antlers and pelts.

By Lily Huang | NEWSWEEK
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Elk still range across parts of North America, but every hunting season brings a greater challenge to find the sought-after bull with a towering spread of antlers. Africa and Asia still have elephants, but Roosevelt would have regarded most of them as freaks, because they don't have tusks. Researchers describe what's happening as none other than the selection process that Darwin made famous: the fittest of a species survive to reproduce and pass along their traits to succeeding generations, while the traits of the unfit gradually disappear. Selective hunting—picking out individuals with the best horns or antlers, or the largest piece of hide—works in reverse: the evolutionary loser is not the small and defenseless, but the biggest and best-equipped to win mates or fend off attackers.

When hunting is severe enough to outstrip other threats to survival, the unsought, middling individuals make out better than the alpha animals, and the species changes. "Survival of the fittest" is still the rule, but the "fit" begin to look unlike what you might expect. And looks aren't the only things changing: behavior adapts too, from how hunted animals act to how they reproduce. There's nothing wrong with a species getting molded over time by new kinds of risk. But some experts believe problems arise when these changes make no evolutionary sense.

Ram Mountain in Alberta, Canada, is home to a population of bighorn sheep, whose most vulnerable individuals are males with thick, curving horns that give them a regal, Princess Leia look. In the course of 30 years of study, biologist Marco Festa-Bianchet of the University of Sherbrooke in Quebec found a roughly 25 percent decline in the size of these horns, and both male and female sheep getting smaller. There's no mystery on Ram Mountain: male sheep with big horns tend to be larger and produce larger offspring. During the fall rut, or breeding season, these alpha rams mate more than any other males, by winning fights or thwarting other males' access to their ewes. Their success, however, is contingent upon their surviving the two-month hunting season just before the rut, and in a strange way, they're competing against their horns. Around the age of 4, their horn size makes them legal game—several years before their reproductive peak. That means smaller-horned males get far more opportunity to mate.

Other species are shrinking, too. Australia's red kangaroo has become noticeably smaller as poachers target the largest animals for leather. The phenomenon has been most apparent in harvested fish: since fishing nets began capturing only fish of sufficient size in the 1980s, the Atlantic cod and salmon, several flounders and the northern pike have all propagated in miniature.

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"Losers" tend not to be very good breeders, meaning that this demographic shift ultimately threatens the viability of a species. Researchers also worry that the surviving animals are left with a narrower gene pool. In highly controlled environments, a species with frighteningly little genetic diversity can persist—think of the extremes of domesticated animals like thoroughbred horses or commercial chickens—but in real ecosystems changes are unpredictable. Artificially selecting animals in the wild—in effect, breeding them—is "a very risky game," says Columbia's Melnick. "It's highly likely to result in the end of a species."
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Battle Over Critical Manatee Habitat Re-ignites After Yacht Club Approval |

Just as populations of manatees -- Florida's state mammal -- are drawing back from the brink of extinction, federal regulators have approved a yacht club on a river that advocates say attracts roughly a quarter of all Southwest Florida manatees in the winter.

Boat collisions are one of the leading causes of death for manatees. And the prospect that 128 yachts could soon be harbored in a prime manatee area has alarmed environmental groups.

Four national conservation groups, including Save the Manatee Club and Defenders of Wildlife, recently petitioned the U.S. Fish and Wildlife Service to update a 30-year-old list of where manatees congregate, feed and breed. The petition seeks to stop development that puts more boats in places where manatees live.

"It's just long overdue," said Patrick Rose, executive director of Save the Manatee Club.

The petition has reignited a long-running battle between conservationists and boaters, frustrated by slow speed limits in manatee-protected waterways.

The river, a small tributary of the Caloosahatchee near Fort Myers, hosts a power plant that warms the water and attracts hundreds of manatees on chilly winter days.

Cold stress and toxic algae blooms are the top natural manatee killers. Boat collisions are their leading human-inflicted cause of death. Lee County frequently leads the state in the number of manatees killed by boats.

"The speed zones that are there are not there for the manatees in and of themselves. They are there because the boats are there," Rose said. "If it's really, truly critical habitat, maybe we shouldn't put more boats in those areas."

The federal government recognized the manatee as an endangered species in 1967. Since then, it has been illegal to harm manatees or destroy their designated habitat. The rules have helped manatees increase their numbers in most parts of Florida. The exception is Southwest Florida, where red tide algae pose a frequent threat.

The state Fish and Wildlife Conservation Commission conducts an aerial manatee count each year, but there are no reliable measures of the actual manatee population. At last count in 2007, 2,817 manatees were tallied.

Also, natural warm springs once helped manatees stay warm in the winter, but drinking water and irrigation demands have eliminated a large number of springs throughout the state. Power plants that constantly discharge warm water have replaced springs as sources for warm water.

The convergence of manatees basking in the Orange River's warmth and 128 yachts runs counter to the notion of protecting an endangered species, Rose said.

"It's crazy to think the most critical manatee refuge on the west coast would not be in critical habitat," Rose said.Just as populations of manatees -- Florida's state mammal -- are drawing back from the brink of extinction, federal... more

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Groups seek 'critical' habitat for manatees | floridatoday.com | FLORIDA TODAY

PHOTO: A female manatee and her calf make their way through the canals near St. George Court and Jolly Roger Drive in Satellite Beach. Environmental groups want more habitat in Brevard County and elsewhere in Florida declared "critical" for manatee survival.

Four conservation groups, including Save the Manatee Club, formally petitioned the U.S. Fish and Wildlife Service to declare more places where manatees hang out to be "critical habitat" designations.

In Brevard, the places include manmade canals such as Berkeley Canal in Satellite Beach and the C-54 Canal in south Palm Bay, as well as natural tributaries to the Indian River Lagoon such as the St. Sebastian River, Mullet Creek, Turkey Creek and Crane Creek.

The designations would add another layer of scrutiny in permitting marine structures in those areas. While it doesn't by itself keep docks, marinas and other marine structures from being built, the designation could tip the balance, said Katie Tripp, director of science and conservation for Save the Manatee Club.

Under the Endangered Species Act, federal agencies can't authorize an action that causes the "destruction or adverse modification" of habitat designated as "critical" to the survival and recovery of an endangered species.

The groups that submitted the 64-page petition say new research since the original critical habitat designations were made in 1976 proves a need for more critical habitat designations, with more precise definitions.

"What this aims to do is clarify what that original list meant," Tripp said of the petition. "Instead of just listing a water body, it explains why."

Federal law requires the U.S. Fish and Wildlife Service, within 90 days of receiving such a petition, to determine whether it "presents substantial scientific information indicating that the revision may be warranted."

If the service makes that determination, then the agency would solicit comments through a lengthy public process, then publish the new critical habitat areas in the Federal Register, before they could take effect.

Steve Webster, executive director of Florida Marine Contractors Association, a trade group of dock builders, blasted Save the Manatee Club as an organization "that has outlived its purpose."

Please Visit: http://www.savethemanatee.orgPHOTO: A female manatee and her calf make their way through the canals near St. George Court and Jolly Roger Drive in Satellite... more