Ranchers often argue that cattle grazing is the best way to combat cheatgrass, an aggressive invader that has taken over vast areas of the Great Basin, destroying the native sagebrush ecosystem and fueling huge wildfires.

But a study published today in the Journal of Applied Ecology arrives at the opposite conclusion. Reseachers who studied 75 Great Basin sites invaded by cheatgrass found that greater grazing intensity promoted the alien’s spread.

“Our findings raise serious concerns regarding proposals to use cattle grazing to control [cheatgrass] in these systems where remnant bunchgrass communities persist,” wrote scientists from Augustana College, the U.S. Geological Survey and Oregon State University.

It’s long been known that livestock played a role in speading cheatgrass, an annual grass from Eurasia that is thought to have been accidentally introduced to the West by settlers in the late 1800s. The study attempts to develop a better understanding of the...

Some say that you can’t put a price on precious natural resources. As of this week, you can.

The public and private tab for conserving the nation’s fish, wildlife and natural resources is close to $40 billion a year, according to a study released this week.

The analysis, commissioned by the National Fish and Wildlife Foundation, considered the jobs, tax revenue and other economic effects from federal state and private investment in conservation.

The total -- $38.8 billion — stimulates as much as $93.2 billion in economic activity, the study found.

A coalition of more than 1,200 conservation groups extrapolated the numbers from the new study and came up with another set of economic indicators.

According to the group, America’s Voice for Conservation, Recreation and Preservation, the economic impact from resource conservation, outdoor recreation and historic preservation in the United States is $1.7 trillion a year, which produces $211 billion in tax revenue and...

Two federal agencies on Friday announced a major review of how seismic testing for oil and gas deposits affects marine mammals and fish in deep waters off the Gulf of Mexico.

So-called seismic surveys entail blasts from air guns or other ship-borne devices that send out powerful sound waves that reflect the shape and extent of oil and gas fields under the ocean floor. Industry officials say the practice is necessary for efficient, safe exploration in deep seas.

The testing has long been controversial. Environmental groups have taken companies connected to the tests to court many times, contending that the blasts cause hearing loss in whales and other protected species.

In addition, scientists have observed avoidance behaviors among marine mammals and fish during testing, which can take place over weeks.

Seismic testing has also caused disturbances to animals' feeding and breeding, according to some scientists.

The multi-year review is to begin in June with the Bureau of Ocean Energy...

The U.S. Fish and Wildlife Service has two months to identify suitable in-water nesting and migratory habitat for endangered loggerhead sea turtles, according to a legal settlement filed this week.

The agreement — between the wildlife service and the groups Center for Biological Diversity, Turtle Island Restoration Network and Oceana — gives the government until July 1 to propose feeding, breeding and migratory habitat in the Gulf of Mexico and U.S. waters in the Atlantic and Pacific oceans.

PHOTOS: 10 shocking facts about turtles

The final critical habitat protections must be in place by July 1, 2014, according to the settlement filed Thursday in U.S. district court.

The Fish and Wildlife Service in March proposed protecting more than 739 miles of critical habitat for loggerhead sea turtles on their nesting beaches from North Carolina to Mississippi, about 84% of the turtle’s known nesting areas.

Although honeybee loss slowed last year, it remains at dangerously high levels, according to a new federal report that concluded there was no single remedy for the colony collapse that has hit America’s hard-working crop pollinators.

The report, released Thursday by the U.S. Department of Agriculture and the Environmental Protection Agency, attributed the colony decline to a number of factors, including pesticide exposure, parasites and poor nutrition.

Since 2006, when colony collapse disorder emerged, an estimated 10 million bee hives, worth about $2 billion, have been lost. During that period, about 30% of colonies have died every year, although in 2012 the figure dropped to 22%.

The figures are grim news for the food industry. Pollination, principally by honeybees, is necessary for the production of about one-third of all food and beverages. California almond growers alone use more than 60% of all managed colonies. 

“Currently, the survivorship of honeybee colonies is...

The Kelso Depot Visitor Center in Mojave National Preserve, the park’s popular historic site, is about to be affected by federal spending cuts.

Starting next week, the visitor center will be closed on Wednesdays and Thursdays. The visitor center will remain open Fridays through Tuesdays from 9 a.m. to 5 p.m.

The cutbacks are part of across-the-board federal spending cuts, also known as sequestration. Park officials said the budget rollbacks reduced the number of seasonal workers who would have staffed the recently reopened train depot.

The preserve’s headquarters information center in Barstow will continue to be open Mondays through Fridays from 8 a.m. to 4:30 p.m.

The park itself is open every day with no entrance fee. All other facilities, including campgrounds and trails, remain open.

Confidential surveys of water officials, water users and others involved with the Sacramento-San Joaquin Delta offer some telling insight on why the delta is stuck in a perpetual quagmire.

When it comes to fixing the hub of California’s water system, most parties would prefer it if someone else made the sacrifices.

The surveys, conducted last year by the nonpartisan Public Policy Institute of California and discussed in a new institute report, found that there was general agreement with scientists about the nature of the problems that have pushed several of the delta’s native fish species to the brink of extinction: altered and diminished water flows, water pollution, loss of fish and wildlife habitat, invasive species and fishery management.

But interest groups differed on the importance of those stressors, depending on what it would take to fix them — and who would do the fixing.

Water "exporters avoided measures that would reduce their diversions (either directly...

The U.S. Department of the Interior will become the first federal agency to take advantage of a new program to update its fleet of vehicles with gas-sipping hybrids.

The initiative is part of a General Services Administration effort to replace aging government cars with as many as 10,000 hybrids.

The Interior Department will receive 300 gasoline and alternative-fuel vehicles--about a third of the vehicles the department is expecting to replace.

Under the Fleet Consolidation program, the GSA will fund the cost difference to purchase hybrid sedans.

That fresh, pine-scented mountain air that you happily breathe in the Sierra Nevada could be hazardous to your health.

Samples taken by federal scientists in Devils Postpile National Monument, southeast of Yosemite National Park, show that ozone levels occassionally exceed state air pollution standards.

“Even at remote eastern Sierra locations, ozone air pollution may be a problem for human and ecosystem health,” said Andrzej Bytnerowicz, a U.S. Forest Service research ecologist and lead author of a study recently published in the journal Atmospheric Environment.

Researchers sampled the air at Soda Springs Meadow, elevation 6,918 feet, during the summers of 2008 and 2007. Though the testing found less air pollution than has been documented in portions of the western Sierra, emissions from widespread wildfires in 2008 and urban pollution blown from the Bay Area and the Central Valley elevated ozone levels on some days.

The highest ozone measurements were taken on days when...

Officials at Yosemite National Park say snow plows will begin clearing Tioga Road next week and hope to reopen the highway by May 11.

The road across Tioga Pass is a crucial one for tourists crossing the Sierra Nevada range. Park officials said a dry winter should speed the work.

Plowing on the road to Glacier Point began this week, according to Yosemite spokeswoman Kari Cobb, with a projected opening of May 3. Mariposa Grove road is already open

Cobb cautioned that the opening dates are subject to late spring storms, road damage and other  safety concerns.

A dry winter left the park with about 53% of the normal snowpack.

Academic researchers and federal scientists have for the first time come up with direct evidence of feral cats killing endangered Hawaiian petrels. The study, by scientists from the University of Hawaii, the National Park Service and the U.S. Geological Survey, confirms what has been widely suspected, that wild cats are playing an important role in the population decline of the rare birds.

The study involved monitoring of 14 Hawaiian petrel burrows with digital infrared video cameras in 2007 and 2008 on the island of Hawaii. The photographic evidence of feral cats at petrel nesting burrows.

In one video, a cat was shown waiting near the entrance of a burrow for more than an hour. When a petrel chick emerged, the cat quickly grabbed it and the remains of the small bird were later found nearby. Researchers attributed other kills to the condition of the bird carcasses and the presence of cat scat.

Hawaiian petrels spend most of their lives at sea and return to land to breed. The species...