environment and natural resources

Ripple receives national honor from Defenders of Wildlife

CORVALLIS, Ore. – William Ripple, a professor in the Department of Forest Ecosystems and Society at Oregon State University, will receive the Spirit of Defenders Award for Science this month from the Defenders of Wildlife, a national organization dedicated to preserving native wildlife species and habitats.

The honor recognizes Ripple’s pioneering work in the study of “trophic cascades” and the importance of large predators to the proper function of entire ecosystems.

Ripple, OSU colleague Robert Beschta and graduate students have done numerous studies in recent years outlining how the decline or disappearance of predators such as wolves and cougars has led to massive ecosystem changes in everything from vegetation and tree survival to streams and insect life.

The other three individuals to be honored at the reception in September in Washington, D.C., are Ted Turner, receiving a legacy award; Sen. Sheldon Whitehouse, receiving an award for public service; and Terry Pelster, an award for citizen advocacy.

Founded in 1947, the Defenders of Wildlife is a national leader in science-based wildlife conservation, with a goal of protecting all native wild animals and plants in their natural communities. It has more than one million members and activists worldwide.

Some of the early work done by the OSU researchers has been in Yellowstone National Park, where the reintroduction of wolves has stopped decades of decline in aspen and stream ecosystems, caused by excessive populations and uncontrolled behavior of elk. As elk populations were reduced and their grazing behavior changed by what scientists refer to as the “ecology of fear,” streams, trees and many other plants and animals have begun a solid recovery.

The researchers have helped define how the loss of large predators is important not just for population control of grazing animals, but how the fear of predation dramatically changes their behavior, 365 days a year, day and night. In a range of sites, often at national parks in the United States, the scientists have observed much the same forces at work.

Ripple received his doctorate from OSU and has been on the OSU faculty since 1984.

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Brenda McComb, 541-737-6571

OSU researcher studying beaver impact on desert trout

CORVALLIS - Is the state's largest rodent the friend or foe of an isolated population of endangered trout?

A graduate student in Oregon State University's Department of Fisheries and Wildlife is closing in on the answer with his two-year study of Willow Creek in Oregon's lonesome southeastern corner.

"We don't know for sure yet whether the study will show that the presence of beavers is harmful, neutral or beneficial to the fish, and when we do we won't know how far beyond Willow Creek whatever we determine may be true," said Andrew Talabere, who is conducting the research for his master's degree. "But," he added, "we do know that this study is going to give us another tool to use in the potential recovery of these threatened fish."

Talabere is talking about Lahontan cutthroat trout, the only fish in Willow Creek. The federal government listed the Lahontan cutthroats in that tiny stream and nearby White Horse Creek as threatened in 1991.

Willow Creek is only 18 miles long. It starts in southeastern Oregon's Trout Creek Mountains near the Oregon-Nevada border and runs almost due north toward Steens Mountain. It ends in a marshy area that is a shallow lake during wet climatic periods. A person could jump across the creek in spots.

Several years ago researchers with the Oregon Department of Fish and Wildlife noted that the area right around the banks of Willow and White Horse creeks, damaged in decades past by livestock, wild horses and weather factors such as droughts, was improving. They suspected the improvement could be attributed, at least in part, to a change in how the federal land the creek runs through was managed.

The Bureau of Land Management was working cooperatively with ranchers, environmentalists and state resource managers. The improvement included the return of willows and other trees around the streams, and there seemed to be a related rise in beaver activity, including the number of dams.

Talabere began his field research in 1998 under the supervision of OSU fisheries ecologist Bill Liss and aquatic ecologist Bob Gresswell.

In recent years there has been increasing interest in how beaver ponds affect fish distribution, Talabere noted.

"Some work on this had been done in the Midwest and west of the Cascades. But none had been done in this kind of desert ecosystem.

"There's a lot of concern that beaver ponds increase the water temperature, both because of an increase in the surface area of the stream and because beavers cut down trees, removing shade," he added. Basically, what the OSU graduate student did during two fields seasons was measure shade and other physical characteristics along the stream, and survey the fish in the creek.

For comparison, Talabere and assistants conducted identical studies in stretches of the creek with beaver ponds and in stretches without beaver influences. They also placed special devices in some of the study areas to monitor the water temperature over time.

There is a difference in the beaver pond complexes between the temperature of the water going in and coming out, Talabere says. "The water heats up a degree or so in complexes in our higher-elevation study areas," he said, " and two or three degrees in lower-elevation complexes. But it did that in the study stretches without beaver activity, too."

He hasn't finished analyzing the amount of shade by the creek, but he suspects there is more where beavers are active.

"When I go out to Willow Creek beaver ponds in March," Talabere said, "some of them tend to look like war zones. Clearcut. All stumps. But by July it's all grown back, and more. There have been beavers in North America for three to four million years and willows even longer. They've evolved together."

"This is highly speculative at this point," said Talabere, "but there appear to be more large fish in the beaver complexes (we studied). If that's true, and I haven't analyzed all the data yet, it means the beaver ponds are providing either more food that allows fish to get larger, or greater habitat area. Ultimately what it means for the population is that you grow more large fish per unit of stream and get more reproduction."

The research is featured in an article in the Winter 2000 issue of Oregon's Agricultural Progress, a magazine published by OSU's Agricultural Experiment Station. Copies are available by writing: Jeanne Bush, EESC, 422 Kerr Administration, OSU, Corvallis, OR 97331-2119, or calling Bush at 541-737-3717.

Talabere said he expects to complete his report on what he learned in the study of Willow Creek by July 2000.


Andrew Talabere, 541-757-4263

Study points to U.S. as generator of greenhouse gases

CORVALLIS, Ore. - New research has found that the massive amounts of atmospheric carbon dioxide generated by fossil fuel use in the United States are not completely "offset" by the storage of carbon in growing forests and other vegetation of North America, as some earlier studies had suggested.

The new study, which will be published Friday in the journal Science, may have important implications for the role of the United States in combating the greenhouse effect and global warming.

"Some have argued that the U.S. does not need to reduce greenhouse gas emissions because we're not part of the problem," said Ronald Neilson, a professor of botany at Oregon State University and bioclimatologist with the USDA Forest Service. "Based on this study, we can no longer make that claim."

Neilson was a co-author on this research with scientists from the Max-Planck-Institute for Biogeochemistry in Germany, the Ecosystems Center at Woods Hole, Mass., the National Center for Atmospheric Research in Boulder, Colo., and other universities and agencies.

This debate and controversy, Neilson said, is a complicated but important part of the challenge facing nations around the world as they try to decide what to do about global warming and what responsibilities various countries should have. It's also a detective story of researchers looking for the "missing sink" of carbon. More carbon, they say, is being injected into the atmosphere by industrialized nations than can be clearly accounted for in the Earth's atmosphere, land, vegetation and oceans.

"Some past studies suggested that a big part of the missing carbon sink was in the forests and changing land use practices of North America," Neilson said.

Increasing levels of atmospheric carbon dioxide can literally "fertilize" plants and trees, researchers say, causing them to grow faster. Also, the United States in particular is converting a large amount of former agricultural land back into forests, which also tends to sequester carbon.

"On a global basis, we've estimated the missing sink of carbon at about 1.8 gigatons per year," Neilson said. "One earlier study suggested that changes in the forests and vegetation of North America were sequestering an extra 1.7 gigatons of carbon. Some people pointed to that as evidence that the U.S. had already done its part in the fight against global warming, that we were not contributing much to the problem."

The new research refutes that conclusion.

In their Vegetation and Ecosystem Modeling and Analysis Project, or VEMAP, the group of scientists found that atmospheric fertilization and other phenomena would sequester only an additional .08 gigatons of carbon within the lower 48 states, and possibly double that for all of North America. Regrowth of forest vegetation would sequester no more than an extra one or two times that amount.

In simpler terms, the study suggests at least 70-90 percent of the carbon injected into the atmosphere by fossil fuel use in the U.S. is either staying there or being sequestered somewhere besides North America.

As one of the largest industrialized nations in the world, the U.S. uses huge amounts of coal and petroleum products and is responsible for a major portion of the global total of greenhouse gases. But so far this country has not ratified agreements reached in Kyoto, Japan, under the United Nations Framework Convention on Climate Change, which sought international cooperation on reducing greenhouse gas emissions.

"In the U.S., some people and policy makers remain unconvinced of the reality of global warming and have concerns about the economic impact on jobs or industry if the country were to commit to greenhouse gas reductions," Neilson said. "Other nations, especially in Europe, have taken a different stance and are more receptive to the Kyoto accords."

But as the debate continues about what each nation should do, Neilson said, direct evidence and various computerized climate models make it increasingly clear that global warming is a scientific reality. "The U.S. has warmed by about one-half to one degree in the past century, and models suggest it will warm from about five to nine degrees in the next century," Neilson said. "There are still many people who don't believe these models are accurate, but the balance of evidence suggests they are getting increasingly accurate."

The impact of these climate changes may be profound, researchers say, ranging from drought and massive fires to dramatic changes in vegetation, ecology, and the agricultural potential of land. As the climate warms, there may also be feedback mechanisms that would cause even more carbon to be injected into the atmosphere and compound the greenhouse effects.

The new study also found that a nation's contribution or sequestration of carbon may be quite variable, even from one year to the next. In general, warmer or drier conditions cause carbon release to the atmosphere. So a drought or higher temperatures may change land that absorbs carbon into land that is releasing it, making it very difficult on a short-term basis to create accurate carbon measurements and fair, functional international agreements.

"All of these results indicate that we need to continue to improve our technologies for measuring carbon, determine where it is going, find ways to work through the annual variations and determine what the long-term impacts will be," Neilson said. "But this study clearly contradicts the suggestion that carbon uptake in North America is balancing our carbon emissions from fossil fuels. We are still part of the problem."

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Ron Neilson, 541-750-7303

Scientist issues 'global swarming' warning

CHICAGO - Our planet is threatened by another high-stakes environmental problem linked to human activities, an Oregon State University researcher warned today (March 28) at an international meeting.

Call it, "global swarming."

Throughout the world, non-native plants and animals that range in size from "viruses to water buffalo" are driving out native life forms, wildlife ecologist Bruce Coblentz told scientists assembled in Chicago for the North American Wildlife and Natural Resources Conference.

We haven't yet comprehended the magnitude of the problem, said the OSU researcher, who has studied the impact of non-native creatures much of his career in places such as Aldabra Atoll in the Indian Ocean, the Galapagos Archipelago off the coast of Ecuador and islands off the southern California coast.

In a presentation titled "Biological Invasions: Global Swarming is Heating Up," Coblentz said that "every successful species invasion is analogous to an explosion. An invasion is the shock wave that radiates out from the point of detonation, and each invading species proceeds at its own rate."

Native species often become "living debts" for an invasion, he said. Their eventual extinction, no matter how hard humans try to counteract it, is the price that will be paid within the natural system.

"And we don't even know what the full price is," he added. "In other words, successful biological invasions are going to cause extinctions, but we don't necessarily know when, or whose."

He discussed the spread of non-native European starlings from Central Park in New York City to Alaska in only a little more than 60 years, and Sika deer expanding their range more gradually, but steadily, on the eastern shore of Maryland.

"Homogenization of biotas (the plants, animals and microorganisms of regions) worldwide and the extinction events almost certain to occur as a result will surely shape the course of future organic evolution," the researcher told scientists attending the conference. "The end result, to be played out over the next few million years, is that we are diminishing the options," he added. "Rather than proceeding with a rich diversity of organisms, many of which have evolved to specifically exploit certain unique conditions and environments, future evolution will involve a more limited diversity of organisms that share a single trait of being able to succeed in a human-dominated landscape."

Pretty much every environment in the world already has been disturbed by humans, the researcher emphasized. Also, human transportation systems now allow organisms place-bound for eons to leapfrog oceans and other natural barriers, sometimes as crops, livestock or pets, and sometimes as stowaways.

Biological invasions are expensive to human societies in several ways, Coblentz said, pointing to lost crop production, disease, lost production of desirable native species and physical damage to natural ecosystems and human property.

"Dollar estimates for damages associated with invasive species in the United States alone are staggering," he said. "For example, the Office of Technology Assessment estimated a minimum cost associated with 79 invasive species in the United States to be at least $97 billion for the 85-year period 1906-1991." One researcher put the figure much higher, at more than $137 billion per year, he noted.

How can humans combat the problem more effectively?

"The rate of spread ... is important in determining how quickly and how intensively control measures must be instituted to be effective against an invasive species," Coblentz said. "In fact, the time factor may be the key to beginning to think responsibly about invasions."

"Those (invasions) that occur too slowly to be noticed by our temporal frame of reference may not elicit any reaction by ecologists or natural resource managers," he said. "Nevertheless, they may still be tremendously rapid by measures of ecological time. A seeming non-problem could really be a major problem, but humans are too short-lived to perceive it."

It is ironic that humans would attempt to stem the tide of biological invasions, the researcher noted.

"... Homo sapiens have probably been the most invasive species in the history of the planet," he said. "In comparison with rates of reproduction and dispersal by which we sometimes judge invasibility, humans are quite inferior, yet the outcome of our global invasion from its origin in tropical Africa has been absolute."

The researcher spoke of "bleak" possibilities in the 21st century, in terms of extinction of native creatures.

"On the other hand," he said, "we still have most of our biota and habitats that can be preserved, and the time to assure their preservation has already arrived."


Bruce Coblentz, 541-737-1959

OSU researchers discover high rate of liver cancer in trout

CORVALLIS, Ore. - Researchers at Oregon State University have discovered an unusually high cancer rate in hundreds of rainbow trout at a research facility near Corvallis. One out of every 10 fish was found to have liver cancer, a rate 100 times greater t han the "normal" background rate established in 35 years of research at the facility.

Many fish also are showing severe anemia.

The researchers are now focusing on various potential causes for the cancer outbreak. There are no known fish tumor viruses that could cause such tumors, and nothing is known to have changed in the trout's feed that would account for the sudden cancer inc rease, according to George Bailey, director of the OSU Freshwater/Marine Biomedical Sciences Center, which uses the research facility.

This leads the researchers to suspect the water supply as a possible - and perhaps likely - source. The facility receives its water from a series of wells drawing from a shallow aquifer in the area just east of Corvallis, across the Willamette River. Stan dardized chemical and metal tests on the water have not yet revealed any significant contaminants.

"A great deal more work is needed to identify the contaminant involved, and its source," Bailey said.

The trout showing cancers were spawned from brood stock reared at the research facility. An additional group of trout imported last year as fertilized eggs from the Mt. Shasta hatchery in California also showed the same cancer rate when reared in the faci lity.

"We don't yet know exactly what we are dealing with or the potential risks to people living in that area," Bailey said. "No animal species, including rainbow trout, is an exact predictor of effects on human health. Trout can be extremely sensitive to some carcinogens but, on the other hand, their susceptibility in some cases may be equal to or less than humans."

Tim White, interim provost and executive vice president at OSU, said that while more testing and analysis remains to be done on the nature and source of the carcinogen, "we feel compelled in fulfilling our commitment to the public trust to communicate th is information now.

"While we cannot conclude today that this discovery constitutes a significant human health hazard to people using water in that area, we also cannot rule this possibility out," White said.

"Because of this possibility, we decided upon the course of engaging the proper public agencies and notifying the public," White added. "Indeed, it is fortunate that we have a world class research facility at that site which was conducting studies that ha ve served to alert us of a possible environmental problem."

The university is working with the Oregon Department of Environmental Quality, the Oregon Health Division, and the Linn County Health Department to further assess the situation and determine next steps. The Oregon Health Division, 541-752-7394, oversees p ublic health in Oregon, and the Department of Environmental Quality, 503-229-5983, investigates toxic spills and other environmental contamination.

This is the second incident in 15 months where fish have died or otherwise been affected at the OSU laboratory. In December of 1998, several thousand rainbow trout at the facility died within a 48-hour period. Researchers concluded the 98-percent mortali ty rate was caused by an unknown contaminant passing through the system. The 1998 contaminant could not have come from the trout food, Bailey said, because trout of all ages died, including those too young to be fed. "Therefore, we think it can only have come through the water supply."

Water is supplied to the area by a shallow aquifer, which has never been mapped. Fortunately, Bailey said, another nearby OSU fish research facility has suffered no problems from its water supply. That facility gets its water from the same general aquifer a mile away.

Bailey says it is possible that the recently discovered cancerous tumors were caused by months of exposure to a lower dose of the same toxic agent in the water. These tumors could not be detected earlier, he pointed out, because they take about nine mont hs to develop. Tests just confirmed the tumors to be cancerous.

The trout with cancerous tumors were "control" fish from a study conducted by Bailey, a leading national expert in cancer and cancer prevention. Bailey said the fish received a pure, standard diet formula that has been unchanged for the past three decade s of research. The researchers were surprised to observe the declining health of some of these control fish. Many fish in this ongoing study were smaller than expected and in obvious poor condition. Follow-up examinations revealed abnormally low productio n of red blood cells, or anemia.

When the study was completed, the control trout were examined internally and 10 percent of them were found to have developed the cancerous tumors.

Bailey, who holds the title of "Distinguished Professor of Environmental and Molecular Toxicology," says his colleagues have never seen such conditions in control fish. While it is of concern and needs further study, "it is too early to conclude that the re is a human health hazard."

"Trout can be more susceptible to things than you and I are," he said. "There is a compound, for example, called aflatoxin that the Food and Drug Administration allows in foods such as peanut butter at 20 parts per billion. However, when you give aflatox in to rainbow trout at this rate, it causes cancer in 40 percent of them.

"The flip side," he said, "is that there are examples where trout are less susceptible than humans to certain contaminants. And since we don't know what we're dealing with, we need to keep an open mind."

The fish research facility - known as the Food Technology and Nutrition Lab - is located just east of Corvallis in Linn County.

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George Bailey, OSU, 541-737-3164

OSU president to be honored by landscape ecologists

CORVALLIS - Oregon State University President Paul Risser will be honored by the U.S. chapter of the International Association for Landscape Ecology at the group's annual awards banquet on April 17 in Fort Lauderdale, Fla.

Risser will receive the 2000 Distinguished Landscape Ecologist Award, which is given by the association for outstanding scientific achievement in landscape ecology over a period of a decade or more. It is the most prestigious honor bestowed by the chapter.

"I'm honored to receive this award," Risser said. "The association is active in natural resource management, land planning and design, conservation, and land use policy. I truly appreciate the fact that they recognize my work in this field."

Risser, who has been president of OSU since Jan. 1, 1996, is an internationally known scientist. He began his academic career as a biologist and ecologist, studying grassland and forest ecosystems, environmental planning and management, and global change.

A fellow of the American Association for the Advancement of Science and the American Academy of Arts and Sciences, Risser has been active in national and international science organizations. He served as president of the Ecological Society of America and the American Institute of Biological Sciences, and was secretary general to the Scientific Committee on Problems of the Environment, headquartered in Paris, France.

The International Association for Landscape Ecology aims to develop landscape ecology as a scientific basis for analysis, planning and management of the landscapes of the world. The association advances international cooperation and interdisciplinary synergism within the field, through scientific, scholarly, educational and communication activities.


Paul Risser, 541-737-4133

Biology colloquium to focus on invading species

CORVALLIS - The global threat to biodiversity posed by invading species will be examined at the 61st annual Biology Colloquium at Oregon State University on April 12, titled "Biological Invasions! The Quiet Global Change."

The program will focus on the economic and ecological havoc caused by nonnative invasive species, like the blackberries that must be dug out by the roots, the opossum in your garbage can, or the hitchhikers customs officials try to intercept when they ask if you're carrying any fruit or vegetables.

The event will be held at the LaSells Stewart Center and is free and open to the public, but registration is required. For more information, visit the web site or contact Christi Sheridan at 541-867-0367 (e-mail: christi.sheridan@hmsc.orst.edu).

The colloquium should be of interest to gardeners, fishing enthusiasts, bird watchers or anyone interested in ecological protection, organizers say.

OSU began hosting an annual biology colloquium in 1940 as a forum for public discussion of research topics relevant to the academic mission of the university and the lives of students and citizens.

An invasive species, experts say, is a newcomer that isn't a good neighbor. For instance, the brown tree snake is implicated in the virtual disappearance of native songbirds on Guam. The gypsy moth made lunch out of Pacific Northwest forests. Nutria today chomp their way through significant portions of public marshland in Chesapeake Bay.

Starlings, introduced by homesick European colonists, compete with regional songbirds for food and nesting areas across the U.S. And zebra mussels, such effective filter feeders they can starve neighboring native clams to death, became known for their skill at plugging pipes.

In the Pacific Northwest, invasive species include the nutria, the European green crab, and a plethora of plant invaders that choke out native vegetation and in some cases alter habitat. There's also the incredibly prolific and tenacious Himalayan blackberry, various crop weeds such as leafy spurge and cheatgrass, and the sunny but sneeze-inducing Scotch Broom, implicated in historical fires that swept through Bandon, Ore.

All of these invaders live in ecological balance in their native habitats. But lacking natural controls, their exploding populations can rupture the ecological balance of their new home, wiping out regional species in the process.

Many invasive species get a foothold due to human intervention, scientists say.

New species often get introduced deliberately by homeowners ordering plants or bringing pets or plants home from trips; by hunters wanting a favorite game animal or a new fishing challenge; by authorities pressed to solve problems ranging from erosion to insect infestations. Some species are simply hitchhikers, tagging along with humans and our cargo as we hopscotch around the globe.

According to the Nature Conservancy and U.S. Department of Agriculture, invasive species have contributed to the decline of more than 400 endangered and threatened species in the U.S. Given the pressures on remaining ecosystems, some worry that invasive species may even alter the course of evolution.

Eradicating invasive populations once they are established can be so difficult and damaging to native neighbors that every state in the nation has been asked to develop a formal method of preventing, identifying and stopping invasions before they take hold. President Clinton created a national Invasive Species Council last February to oversee that effort.

Countries use trade policies to attempt to control the importation of diseases and unwanted species. Agriculturists and natural resource managers frequently must rely on chemical controls for established invasions, and pass along to the consumer the cost of herbicides and crop losses.

The financial costs are staggering.

The European gypsy moth is thought to have cost the U.S. economy $764 million, according to the U.S. Department of Agriculture. The zebra mussel alone may cause $5 billion in damages by the year 2002. And the annual impact of nonnative weeds on the U.S. economy is roughly $13 billion.

Websites and other resources exist to inform gardeners, outdoors lovers and travelers about the problem and how to avoid adding to it. Visit the links page of the colloquium website or contact the Nature Conservancy, the Native Plant Society, the National Park Service, Oregon Sea Grant, or your county Extension agent.


Christi Sheridan, 541-867-0367

Task force to examine well water at OSU research site

CORVALLIS - A task force including representatives of Oregon State University, the Department of Environmental Quality, the Oregon Health Division, and the Linn County Health Department has been formed to determine why trout at an OSU research site have such a high rate of liver cancer.

The OSU fish research laboratory, located east of Corvallis in Linn County, reported rates of cancer in rainbow trout that were 100 times higher than normal. Water for the lab is pumped into the facility from wells.

Researchers will begin analyzing tissue samples from the fish to see if they can determine whether the toxicity can be linked to a chemical contaminant, according to Larry Curtis, head of the Department of Molecular and Environmental Toxicology at OSU and chair of the multi-agency task force.

The DEQ will begin regularly testing the water in hope of identifying the contaminant. It may take a series of heavy rainfalls to trigger any potential problem with the water supply, however, Curtis said. "We have begun the process of trying to identify what is causing these high cancer rates in the fish," Curtis said. "It is hard to say how long it will take, especially if the contamination is occurs periodically."

Curtis said researchers from OSU and the other agencies are exploring the development of a continuous, in-line water monitoring system for the research facility's wells.

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Larry Curtis, 541-737-3791

Scientists create first complete image of Himalayan fault, subduction zone

CORVALLIS, Ore. – An international team of researchers has created the most complete seismic image of the Earth’s crust and upper mantle beneath the rugged Himalaya Mountains, in the process discovering some unusual geologic features that may explain how the region has evolved.

Their findings, published this week in the journal Science, help explain the formation of the world’s largest mountain range, which is still growing.

The researchers discovered that as the Indian and Eurasian tectonic plates collide, the Indian lower crust slides under the Tibetan crust, while the upper mantle peels away from the crust and drops down in a diffuse manner.

“The building of Tibet is not a simple process,” said John Nabelek, an Oregon State University geophysicist and lead author on the Science study. “In part, the mountain building is similar to pushing dirt with a bulldozer except in this case, the Indian sediments pile up into a wedge that is the lesser Himalayan mountains.

“However, an important component of the mass transfer from the upper crust of India to the Himalayas also occurs at depth through viscous processes, while the lower crust continues sliding intact farther north under the Tibet plateau,” Nabelek added.

The findings are important because there has not been clear scientific consensus on the boundaries and processes for that region’s tectonic plates. In fact, the piecemeal images gathered by previous research have led to a series of conflicting models of the lithospheric structure and plate movement.

In this study, the international research team – called Hi-CLIMB (Himalayan-Tibetan Continental Lithosphere during Mountain Building) – was able to create new in-depth images of the Earth’s structure beneath the Himalayas.

The interface between the subducting Indian plate and the upper Himalayan and Tibetan crust is the Main Himalayan thrust fault, which reaches the surface in southern Nepal, Nabelek said. The new images show it extends from the surface to mid-crustal depths in central Tibet, but the shallow part of the fault sticks, leading to historically devastating mega-thrust earthquakes.

“The deep part is ductile,” Nabelek said, “and slips in a continuous fashion. Knowing the depth and geometry of this interface will advance research on a variety of fronts, including the interpretation of strain accumulation from GPS measurements prior to large earthquakes.”

Nabelek, an associate professor in OSU’s College of Oceanic and Atmospheric Sciences, said the lower part of the Indian crust slides about 450 kilometers under the southern Tibetan plate and the mantle appears to shear off and break into sub-parallel segments.

The researchers found evidence that subduction in the fault zone has been occurring from both the north and south sides – likely at different times in its geologic history.

In this project, funded primarily by the National Science Foundation, the researchers deployed and monitored about 230 seismic stations for a period of three years, cutting across 800 kilometers of some of the most remote terrain in the world. The lowest-elevation station was at 12 meters above sea level in Nepal; the highest, nearly 5,500 meters in Tibet. In fact, 30 of the stations were higher than 5,000 meters, or 16,400 feet.

“The research took us from the jungles of Nepal, with its elephants, crocodiles and rhinos, to the barren, wind-swept heights of Tibet in areas where nothing grew for hundreds of miles and there were absolutely no humans around,” Nabelek said. “That remoteness is one reason this region had never previously been completely profiled.”

Other authors on the Science study include Gyorgy Hetenyi and Jerome Vergne of Ecole Normale Superieure in France; Soma Sapkota and Basant Kafle, Department of Mines and Geology in Kathmandu, Nepal; Mei Jiang and Heping Su, Chinese Academy of Geologic Sciences; John Chen, Peking University in Beijing; Bor-Shouh Huang, Academia Sinica in Taiwan; and the Hi-CLIMB Team.

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John Nabelek, 541-737-2757

Multimedia Downloads

Soma Sapkota

Soma Sapkota, of Nepal’s Department of Mines and Geology, at a seismic station in barren, wind-swept central Tibet. (photo courtesy of OSU’s John Nabelek)

Mt. Everest

The Hi-CLIMB (Himalayan-Tibetan Continental Lithosphere during Mountain Building) seismic station at the Mt. Everest base camp in Tibet. (photo courtesy of OSU’s John Nabelek)

Chitwan National Park in Nepal

The researchers go through Chitwan National Park in Nepal after completing the first phase of the network deployment. (photo courtesy of OSU’s John Nabelek)

Restoring gravel mining areas helps fish, scientist says

CORVALLIS - Restoring the land around exhausted Willamette Valley gravel mines as a substitute for natural floodplains lost to development in the 19th and 20th centuries can help endangered fish and other native species, an Oregon State University researcher says.

"Our experimentation with the restoration of off-stream gravel mine areas with pits less than 20 feet deep appears to be positive for fish, plants and animals, when the pits are not too deep," said OSU fisheries ecologist Peter Bayley.

Bayley and colleagues are doing restoration work, in cooperation with the gravel mining industry and the Oregon Department of Fish and Wildlife, around two former mine sites near Corvallis and one near Harrisburg. The research includes making surface water connections by installing channels or culverts to connect the areas to the Willamette River.

"Early data suggests that there are more native species using the restored areas with increased access to the main river, especially during October to May," and that fish grow faster when they are in these areas rather than in the river, Bayley said. This could make ocean-going fish such as juvenile chinook salmon larger and more able to fend for themselves when they enter the ocean phase of their lives, he added.

Besides young salmon, native fish such as cutthroat trout may benefit from restoring floodplains, according to Bayley.

The idea behind the research, the OSU researcher explained, is to partially restore natural floodplain systems that used to exist around the Willamette and other western Oregon rivers. Since the 1850s, he said, floodplains have been isolated from the rivers to allow farming, housing and other human uses.

"We're trying to restore the floodplain areas associated with shallow mines that are less than 20 feet deep, rather than maintain the gravel ponds themselves in their present form," Bayley said. "Backwaters and floodplain lakes are rich with zooplankton. Also, terrestrial creatures such as earthworms, slugs and earwigs are made available as food for fish by flooding.

"Historically, during in the rainy season when the river expanded into floodplains, fish could follow food out into the fields and forests and 'harvest' the bounty produced there during the summer," Bayley said. "For those that migrated, it was like a stop-off diner on their way to the ocean. They still feed like this even when small floodplains are flooded for only a few days."

Bayley has done similar research on the upper Mississippi River and in the Amazon Basin. He started his current research in 1998 by establishing a monitoring program. He and his graduate student Cyndi Baker used a combination of capture methods to identify the fish that lived in the three gravel pits before they were relinked to the Willamette River.

So far, they have found 10 native species of fish out of 20 native species living in the river, as well as 10 non-native species.

"Even before we connected these areas to the Willamette River we noticed young chinook entering the ponds during extremely high floods," he said. Now, with the ponds reconnected to the river, more native fish are entering the areas during the rainy season, the research suggests.

The percentage of non-native fish is higher during July and August when no fish from the river can reach the areas.

"We don't expect to rid these areas of non-native fish," Bayley said, "but we want to learn what we can do to help natives thrive."

Restoration of the areas around gravel ponds with native trees and other plants that stabilize the land surface or provide sources of food should also be of benefit to other creatures such as western pond turtles and red-legged frogs, Bayley believes.

The researcher said finding a beneficial use for former gravel mining areas may surprise some Oregonians. But information on benefits of floodplain habitats to native fishes in Washington State and British Columbia suggests that similar benefits would result in the Willamette Basin.

"When the off-stream mining is finished at a site, parts of the area can be returned to agriculture, but not all of it," he said. "To me the answer to what should be done with the land is very clear.

"We lack natural floodplains while agricultural land dominates the landscape," he said. "However, a functioning floodplain does not have to be a continuous zone along the whole river, and restoration of the small amount of land in off-channel gravel mining would be beneficial locally and provide examples of what could be gained in other floodplain areas."

Providing funding or other support for the research program were the Willamette River Gravel Fund; Morse Brothers, an aggregate company based at Tangent; the Oregon Watershed Enhancement Board; the Corvallis Environmental Center; the Oregon Department of Fish and Wildlife; the Oregon Concrete & Aggregate Producers Association; and the OSU Department of Fisheries and Wildlife.


Peter Bayley, 541-737-0569