environment and natural resources


CORVALLIS - Willamette Valley vegetable growers are experimenting with new ways to grow vegetables while protecting soil and water quality. Their methods combine new ideas of conservation tillage with old ideas of cover crops.

The process begins right after harvest in the fall. Instead of leaving the soil bare and vulnerable to erosion over the winter, these farmers will plant a crop of vetch or low-growing oats to keep their fields covered through the winter.

"Cover crops capture residual fertilizers in the fall, and keep chemicals from leaching into groundwater," explained Richard Dick, professor of soil science at Oregon State University. Cover crops add organic matter that creates air pockets in the soil for water to penetrate and be stored. Erosion is reduced, protecting both streams and soil.

Come spring, the fields will be prepared for planting. But instead of plowing the entire field to bury all of the crop residue, farmers will till only narrow eight-inch strips for seeding and leave the ground in between undisturbed.

Sam Sweeney, a Dayton-area vegetable producer, has seen marked improvement in soil conservation in the two years he has been using this "strip-till" method. Planting on a slope with conventional methods, Sweeney had previously lost soil, water, and nutrients into the creek.

"Strip tilling on that slope creates a barrier of undisturbed soil at each row. These small terraces catch water so it can soak into the soil and not drain off," he said.

Strip-tilling has many advantages, according to John Luna, of OSU's Integrated Farming Systems Program. It minimizes the disruption of desirable organisms such as earthworms in the soil that keep plants healthy. Cover crop residue can help smother weeds. And it limits the impact of tractors and other heavy equipment.

"Soil compaction limits the yield in many Oregon soils," Luna said. "Compacted soil prevents water from moving through the soil and restricts root growth. With conventional tilling methods, farmers traditionally make four to 10 passes through a field. With strip-tillage, growers make one or two passes over a field, and they are ready to plant."

With fewer passes, and more plant material in place, strip-tilling should improve soil structure so it will retain moisture and require less irrigation. Increased organic matter from cover crops can improve soil fertility and may reduce the need for chemical fertilizers.

Strip-till methods were used to plant more than 3,000 acres of vegetable crops in the Willamette Valley this year, yet Luna and others have some reservations.

"Strip-till isn't best for every situation," Luna said. "There are some situations where conventional tillage outperforms strip-tillage, and visa-versa. We don't understand the whole picture yet."

Sweeney concurs. "With all new practices, there is an awful lot to learn," he said.

Strip-till requires growers to invest in new equipment and monitor performance against conventional methods. Sweeney has seen economic savings in labor and fuel from reduced tillage. But speaking for the handful of pioneering vegetable growers in the Willamette Valley, Sweeney said, "Our main motivation is conservation."

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Richard Dick, 541-737-5718

Fertilizers may be linked to amphibian deaths

CORVALLIS, Ore. - Researchers have discovered that a level of nitrogen-based compounds which the EPA says is safe for human drinking water - a level often found in agricultural areas as a result of using crop fertilizers - is enough to kill some species of amphibians.

A new study at Oregon State University, just published in the journal Environmental Toxicology and Chemistry, has shown that several frog, toad and other amphibian species, especially at their more vulnerable larval stages, can be highly susceptible to fa irly low levels of nitrate and nitrite exposure.

When exposed to moderate amounts of nitrates and nitrites, some tadpoles and young frogs reduced their feeding activity, swam less vigorously, experienced disequilibrium, developed physical abnormalities, suffered paralysis and eventually died. In contro l tanks with normal water, none died.

"I think this is clearly a significant problem," said Andrew Blaustein, a professor of zoology at OSU and expert on global amphibian declines. "Right here in the Pacific Northwest we're having localized extinctions of some amphibians and widespread decli nes in others. We now have clear evidence that nitrate and nitrite exposure at levels considered safe for humans or fish is enough to kill amphibians."

Blaustein has done pioneering research on the potential impact of UV-B radiation in sunlight as one possible cause of amphibian problems. He now says that exposure to nitrogen fertilizers - along with habitat destruction, climate change, pollution, patho gens and introduced predators - is probably another part of the answer to an international mystery that has alarmed ecologists around the world.

But this latest part of the puzzle goes to the heart of crop agricultural practices, he said, which depend heavily on the use of artificial fertilizers rich in nitrogen to produce the world's food supply.

In their study, the OSU scientists worked with five species of amphibians, including the Oregon spotted frog, red-legged frog, western toad, Pacific treefrog and northwestern salamander. In the past 40 years, the Oregon spotted frog has largely disappear ed from most of its known historical range - an area of lowlands with intensive agricultural use.

The scientists tested the sensitivity of the amphibians to environmental levels of nitrates and nitrites. The Oregon spotted frog was the most sensitive - three to four times more vulnerable to nitrates and nitrites than red-legged frogs and Pacific tree frogs. Not by coincidence, the scientists believe, the more-sensitive spotted frog is the species that has almost totally disappeared from these areas.

Levels of nitrites considered safe for human drinking water killed over half of the Oregon spotted frog tadpoles after 15 days of exposure. All five species showed a similar level of mortality at levels of nitrites that were higher, but still well below t hose that the EPA considers safe for warm water fishes.

Nitrates themselves are of low toxicity, the study pointed out, but they cause health problems when reduced to nitrites. Nitrite levels can become higher in specific areas such as shore sites with high contents of organic matter, and also be concentrated by ranch animal manures. And nitrate can be reduced to nitrite in the gastrointestinal tract - especially in younger animals.

The study results indicate that water quality criteria set up by the EPA does not guarantee the survival of some protected and endangered amphibians, the authors said in their report.

According to Blaustein, health effects such as those caused by nitrates and nitrites may also work in concert with other environmental insults, such as acid rain or UV-B exposure, to compound problems.

"Many people are looking for the one single thing that is causing all these amphibian declines, but in reality it's almost certainly a combination of causes," Blaustein said. "It's clear there can be a synergistic effect that causes higher mortality when you have different problems all occurring at once."

For instance, Blaustein said the furor that has arisen over frog deformities such as extra legs has been linked to a trematode parasite known as a fluke.

"But it's probably not that simple," he said. "These flukes have been around forever and we never observed the level of problem we're now seeing with deformed frogs. It's quite possible this fertilizer issue relates to that, along with killing tadpoles di rectly."

The flukes that can cause amphibian deformities live part of their life cycle in a snail, Blaustein said. Snails eat algae. And higher levels of nitrogen-based fertilizers can cause increased algal growth, increasing the snail populations.

"At one pond near Corvallis, we found 67 percent of the frogs had multiple legs," Blaustein said. "And this was in a wildlife management area, which was not intensively farmed but was only surrounded by agricultural lands."

Measurements of water there showed highly elevated levels of nitrate - up to 11 milligrams per liter - which is just above the EPA legal level for drinking water.

The researchers stated in their report that chemicals used for various purposes, including crop agriculture, may permeate lakes, ponds and streams, making them unsuitable for many amphibians.

One of the amphibian species that appears to be the least vulnerable to nitrates, they said, is bullfrogs - an introduced and voracious predator that in turn preys on other amphibian species and is tending to displace them in many agricultural areas.

"As we look for the cause of declining amphibians, we're going to find a lot of these types of interactions," Blaustein said. "But the fact remains that nitrogen fertilizers by themselves, used at levels considered safe in drinking water, are enough to ki ll some amphibians. So clearly that's part of the answer and a fairly serious concern in its own right. And it's pretty good evidence that we need to think again about the level of these nitrate compounds that we say is safe."

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Andrew Blaustein, 541-737-5356

Water issues solvable in Israeli-Syrian peace talks

CORVALLIS, Ore. - An old conflict over water rights and borders in the Golan Heights is one of the key sticking points holding up the resumption and possible success of peace talks between Israel and Syria, but some experts say it is a manageable problem that can be solved.

Geographers from Oregon State University and Haifa University, who have written several books on exactly these topics, say history has shown that the very seriousness of water disputes can help lay the foundation for firm agreements that lead to cooperation and peaceful settlements.

"Israel's need to protect its crucial water supplies does not have to be a fatal stumbling block to these negotiations," said Aaron Wolf, an assistant professor of geosciences at OSU. Wolf is an expert on the resolution of water resource disputes dating back almost 5,000 years, a consultant on some of the current negotiations, and author of the new book "Water in the Middle East: a Geography of Peace."

"There are a variety of ways we could work this thing out," Wolf said. "If history has taught us anything, it's that even the most serious water disputes can and usually are settled peacefully. You hear a lot about water wars, but in reality one of the last recorded wars over water was in 2,500 B.C."

Wolf is collaborating in OSU laboratories with Arnon Medzini, a visiting professor from Haifa University in Israel and author of two upcoming books on the geopolitics of the Jordan River and Tigris-Euphrates river system in the Middle East. Both scientists say that lessons from history can probably help point the way to resumption of talks and solutions acceptable to both Syria and Israel.

"Right now Israel is seeking a full peace agreement with Syria, considering the return of the Golan Heights to Syria and essentially working out a land-for-peace accord," Wolf said. "But the devil is in the details, exactly what land and under what conditions."

A sticking point, the researchers say, is dispute over a comparatively small amount of land - about 60 square kilometers - scattered in three tracts along the border between Israel and the Golan Heights. But those very small pieces of land , indeed the very creation of this border which dates back to 1923, are oriented to water rights.

In this case, those water resources include access to parts of the Sea of Galilee, the Banyas Springs that are part of the Jordan River headwaters, and control of both sides of the lower Jordan River.

"These water resources together comprise about one-third of Israel's total water supply, and they will insist that those rights be protected," Medzini said. "There are other considerations also about the Golan Heights region, such as military security, but a lot of the concern goes directly to this water."

Even when borders are finalized, the scientists say, Israel will probably demand access to some water, such as the Banyas Springs, that clearly will be on the Syrian side of the border. And the protection of water quality is also a consideration, as Israel will want to ensure that Syrian agricultural or industrial activities don't pollute the water that flows downhill into its drinking water supplies.

A fundamental key to the solution and part of the historical precedent, Wolf said, is to separate the issue of sovereignty over the land from the rights to, and use of, the water that flows through it.

"There are places where one side or the other will demand, with justification, sovereignty over certain tracts of land," Wolf said. "But the actual borders in some cases were drawn the way they were because of concerns about water rights and water resources. If we look at those concerns separately from the issue of sovereignty, there are usually ways that a compromise can be reached."

In the arid Middle East, the researchers said, it's becoming increasingly common to trade not only land for peace, but water for peace. Formal leases can and have been drawn up providing for purchase or exchanges of water. And bartering is possible, where a water rights concession is made in one locale in exchange for other water rights elsewhere.

"Once you get past the issue of sovereignty over the land, there are a lot of things we can do with the water," Wolf said. "For instance, Turkey and Syria have an ongoing water dispute on the Euphrates River. But Turkey and the U.S. are important NATO allies. Maybe Turkey could be persuaded to concede a modest amount of water to Syria in this different dispute, in exchange for some Syrian concessions on the Israeli border. That's just one of several possibilities."

The researchers said because of its very value and complexity, water rights can often be negotiated to produce "win-win" situations that both sides can live with. Wolf, in fact, has created a computerized database of 3,600 water treaties over almost 5,000 years that show different ways problems have been solved throughout recorded time - and how water treaties have been honored even as wars raged around them.

There's almost no such thing as a new type of water conflict that hasn't been seen, he said, and those ancient conflicts can point the way to modern solutions.

Some critics, Wolf said, are alluding to the problems over water as a final reason that Israel should not even consider giving up the Golan Heights or pursuing other peace initiatives with Syria.

"There are extremely strong feeling in this area that go back to conflicts of the past, and there may be people who don't want any type of treaty between Israel and Syria," Wolf said. "Those are different problems. But I can guarantee you the issues over water should not stop this peace process from going forward. These are problems we can solve, and history will show us the way."

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Aaron Wolf and Arnon Medzini, 541-737-2722

Amphibian declines complicated, disturbing

WASHINGTON, D.C. - People who are looking for a magic bullet that will explain all of the amphibian deaths and declines around the world are going to be disappointed, a leading expert said Friday at the annual meeting of the American Association for the Advancement of Science.

It's now a certainty that there are multiple causes contributing to this problem, said Andrew Blaustein, a professor of zoology at Oregon State University and one of the pioneers in this field of study. But the lack of a single, definite cause does not diminish the seriousness of this alarming ecological phenomenon, he said.

"At this point we can say for sure that there are several causes of amphibian declines, which include rising levels of UV-B radiation in sunlight, pathogens, pollutants, habitat destruction, introduced predators and most recently, crop fertilizers," Blaustein said. "But the overall result is that this group of animals which has been around since the time of the dinosaurs is now in serious decline all over the world. And some of the things that are killing frogs almost certainly have implications for other animal species, including humans."

The multiple causes of amphibian declines, in fact, helps to illustrate how ecological changes may have a synergistic effect to compound problems, Blaustein said. In various instances it might be that UV-B radiation, or pathogens, or high nitrate levels by themselves would not be enough to cause death or deformity.

Put them all together and you have far more serious impacts, he said, such as: The 14 species of amphibians that have disappeared from Australia in recent years. The five species of amphibians in the Pacific Northwest of the United States that are listed as candidates for the endangered species list. The extinction of the golden toad in Costa Rica. Massive egg mortalities of the Cascades frog in Oregon. Amphibian declines in Europe, South America, Asia, Africa. Even problems in the pristine confines of Yosemite National Park.

"This is an incredibly complex problem, a disturbing one, and there's no end in sight," he said. In 1997, Blaustein published a major paper in Proceedings of the National Academy of Sciences which linked ambient but rising levels of UV-B radiation in sunlight to physical deformities in amphibians. This field study found that more than 90 percent of the salamander embryos not shielded from UV-B radiation either died or hatched with deformities, whereas practically all of those protected by special filters survived and were perfectly normal.

In 1998, Blaustein published a study which correlated an increase in UV-B radiation to retinal damage in the Cascades frog. The authors pointed out that the effect of solar UV radiation on the eye and retina are well known in animals and that the risk increases at higher altitudes. In frogs, this could lead to progressive decline in visual ability, impairment of visually guided behaviors, and less successful avoidance of predators. They concluded that increasing terrestrial levels of solar UV radiation represent a serious environmental threat to species across many ecosystems, including humans.

In late 1999, Blaustein published a study in the journal Environmental Toxicology that showed a level of nitrogen-based compounds the EPA says is safe for human drinking water was high enough to kill some species of amphibians. Levels of this type are often found in agricultural areas as a result of using crop fertilizers, the authors said. When exposed to them, some tadpoles and young frogs reduced their feeding activity, swam less vigorously, experienced disequilibrium, developed physical abnormalities, suffered paralysis and eventually died.

And problems such as that, Blaustein said, may go even further.

"The furor that has arisen over frog deformities such as extra legs has been linked to a trematode parasite known as a fluke," Blaustein said. "But these flukes have been around forever and we never observed the level of problem we're now seeing with deformed frogs. One thing we know is that these flukes live part of their life cycle in a snail. Snails eat algae. And higher levels of nitrogen-based fertilizers can cause increased algal growth, increasing the snail populations."

Those types of linkages, he said - intricate, complicated, sometimes even unproven - are starting to crop up more and more in the strange case of declining amphibians. It means that the Earth's ecological systems work in a delicate balance and that seemingly trivial impacts in one area can become magnified as they ripple through the ecosystem, with unintended results or consequences that are difficult to predict and sometimes frightening in their scope.

For some time, researchers have been referring to the dying frogs as the "canary in the coal mine," an early warning sign of environmental danger.

What's less clear, Blaustein said, is exactly what insult, or combination of them, killed these animals, or caused their diseases and deformities.

Or, he added, which species will be the next to fall.

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Andrew Blaustein, 541-737-5356

OSU president to speak at Columbia River conference IV

CORVALLIS - Oregon State University President Paul Risser will speak on biodiversity and its role in maintaining ecosystems at the upcoming Columbia River Conference IV, the fourth in a series of conferences examining partnerships in the Columbia River Watershed.

The conference is scheduled for March 16-17 at the Skamania Lodge Conference Center in Stevenson, Wash. It is open to all persons interested in the future of the river system.

The two-day event will explore the roles of individuals, businesses, governments and organizations in solving problems associated with the river, said Bill Krueger, a member of the conference advisory committee. Krueger is also head of the Oregon State University Department of Rangeland Resources, which is co-sponsoring the conference along with the University of Washington's Sea Grant Program.

Keynote speakers for the conference include Bill Dietrich, Pulitzer Prize-winning journalist and author of books and articles on the Columbia River; Jack Ward Thomas, professor of forestry at Montana State University and former chief of the U.S. Forest Service, and Jim Lichatowich, fisheries biologist.

The conference also features concurrent sessions on several topics including international and national indicators of sustainability affecting the Columbia Basin; climatic effects and changes relating to fisheries management; science in land management, and explorations into Columbia River curricula.

The registration fee is $150; a limited number of scholarships are available to cover registration fees. These awards are intended to assist individuals without agency, industry, business, or other sponsorship support.

For more conference information, contact Susan Hester, Washington Sea Grant Program, 3716 Brooklyn Ave. NE, Seattle, WA 98105; telephone: 206-685-9117; e-mail: shester@u.washington.edu.


Bill Krueger, 541-737-1615

Asteroid devastation could even be worse than feared

CORVALLIS, Ore. - Researchers say in a new report that if a huge asteroid were to hit the Earth, the catastrophic destruction it causes, and even the "impact winter" that follows, might only be a prelude to a different, but very deadly phase that starts later on.

They're calling it, "ultraviolet spring."

In an analysis of the secondary ecological repercussions of a major asteroid impact, scientists from Oregon State University and the British Antarctic Survey have outlined some of the residual effects of ozone depletion, acid rain and increased levels o f harmful ultraviolet radiation. The results were just published in the journal Ecology Letters.

The findings are frightening. As a number of popular movies have illustrated in recent years, a big asteroid or comet impact would in fact produce enormous devastation, huge tidal waves, and a global dust cloud that would block the sun and choke the plane t in icy, winter-like conditions for months. Many experts believe such conditions existed on Earth following an impact around the Cretaceous-Tertiary, or K-T boundary, when there was a massive extinction of many animals, including the dinosaurs.

That's pretty bad. But according to Andrew Blaustein, a professor of zoology at Oregon State University, there's more to the story.

"Scientists have pretty well documented the immediate destruction of an asteroid impact and even the impact winter which its dust cloud would create," Blaustein said. "But our study suggests that's just the beginning of the ecological disaster, not the e nd of it."

Blaustein and colleague Charles Cockell examined an asteroid impact of a magnitude similar to the one that occurred around the K-T boundary, which is believed to have hit off the Yucatan Peninsula with a force of almost one trillion megatons.

The immediate results would be catastrophic destruction and an impact winter, with widespread death of plants and the large terrestrial animals - including humans - that most directly depend on those plants for food. That's the beginning of an ugly scena rio, the researchers say.

As a result of the impact, the atmosphere would become loaded with nitric oxide, causing massive amounts of acid rain. As they become acidified, the lakes and rivers would have reduced amounts of dissolved organic carbons, which would allow much greater p enetration of ultraviolet light.

At first, of course, the ultraviolet rays would be blocked by the dust cloud, which sets the stage for a greater disaster later on. Many animals depend on some exposure to ultraviolet light to keep operational their biological protective mechanisms agains t it - without any such light, those protective mechanisms would be eroded or lost.

During the extended winter, animals across the biological spectrum would become weaker, starved and more vulnerable. Many would die. Then comes ultraviolet spring, shining down on surviving plants and animals that have lost their resistance to ultraviolet radiation and penetrating more deeply, with greater intensity, into shallow waters than it ever has before.

"By our calculations, the dust cloud would shield the Earth from ultraviolet light for an extended period, with it taking about 390 days after impact before enough dust settled that there would be an ultraviolet level equal to before the impact. After tha t, the ozone depletion would cause levels of ultraviolet radiation to at least double, about 600 days after impact."

According to their study, these factors would lead to ultraviolet-related DNA damage about 1,000 times higher than normal, and general ultraviolet damage to plants about 500 times higher than normal. Ultraviolet radiation can cause mutations, cancer, and cataracts. It can kill plants or slow their growth, suppressing the photosynthesis which forms the base of the world's food chain.

Smaller asteroid impacts, which have happened far more frequently in Earth's history, theoretically might cause similar or even worse problems with ultraviolet exposure, the researchers say. The ozone depletion would be less, but there would also be less of a protective dust cloud.

"Part of what we're trying to stress here is that with an asteroid collision, there will be many synergistic effects on the environment that go far beyond the initial impact," said Cockell, a researcher with the British Antarctic Survey who did some of th is analysis while formerly working with NASA. "Effects such as acid rain, fires, the dust clouds, cold temperatures, ozone depletion and ultraviolet radiation could all build upon each other."

During the K-T event, the scientists said, many of the animals may actually have been spared most of the ultraviolet spring they envision. That impact, oddly enough, hit a portion of the Earth's crust that was rich in anhydrite rocks. This produced a 12-y ear sulfate haze that blocked much of the ultraviolet radiation. But it was a lucky shot - that type of rock covers less than 1 percent of the Earth's surface.

So when the next "big one" comes, the scientists said, the ecological repercussions may be more savage than any of those known in Earth's long history. The collision will be devastating, the "impact winter" deadly.

But it will be the ultraviolet spring that helps finish off the survivors.

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Andrew Blaustein, 541-737-5356

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