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Oregon State University Agricultural Research updates

Restored Gravel Mining Areas Help Fish

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

Men moving fish trap in stream.

OSU fisheries ecologist Peter Bayley, right, and his research assistants maneuver a live fish trap into a connecting channel. Photo: Peter Klingeman

"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, Bayley said.

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 when the land is flooded.

"Historically, during the rainy season when the river expanded into floodplains, fish could follow the flood out into the fields and forests and 'harvest' the bounty produced there during the previous summer," Bayley said. "For those species 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.

"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 connected to the river during most months, more native fish are entering the areas during the rainy season, the research suggests.

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.

"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."

Funding or other support for the research program was provided by 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.

Hardy Dorper Sheep Evaluated by OSU Animal Scientists

A unique new flock has taken up residence at the Oregon State University Sheep Center. They are Dorper lambs, which at first glance look a bit like a herd of a tiny black-and-white Holstein cows.

Last fall, OSU animal science researchers bred 100 ewes with two Dorper rams. As a result, about 160 Dorper crossbred lambs were born this spring at the Sheep Center. They are part of a research project to test their suitability for production in Oregon, said Howard Meyer, an OSU animal sciences professor.

Dorpers were developed in South Africa from a cross between Dorsets, a cream-colored English wool breed, and the black-headed Persian, a haired sheep. Dorper sheep usually have a black head and a cream-colored body, while their crossbred lambs may have splashes of black or primarily black coats.

Sheep and lamb.

A flock of black and white Dorper lambs were born at the OSU Sheep Center in the spring. Photo: Tom Gentle

The Dorper lamb project is a sort of piggyback research project for Meyer. At the request of an Oregon Dorper breeder, Meyer agreed to the mating of Dorper and Suffolk rams to the ewes from his main research project to compare the development of the lambs. Interest in the Dorpers is high because they appear to be hardy and fast growing.

Although Dorpers are found in Oklahoma, Ohio and parts of Canada, Meyer's research represents the first time they are being tested in Oregon.

The Dorper breed was imported to the United States in 1995 in embryo form via Canada, said Ron Gunther, who raises Dorpers at River Wood Farms in central Ohio. Gunther said the breed has several unique characteristics that make it attractive to potential lamb breeders. Aside from its hardiness and its good-sized carcass for the meat market, Dorper lambs do not require shearing.

"I call them a shedding breed rather than a hair breed," Gunther said. With the market value of raw wool depressed, it is hard for sheep producers to recoup the cost of shearing, which can be as high as $2.50 a head.

Another attribute of Dorpers is that they will mate almost anytime, as compared to most other varieties of sheep, which are seasonal breeders. "That's an advantage if you are trying to create a uniform supply of lambs," he said.

According to the American Sheep Association, most domestic lamb is consumed on the East and West Coasts, which have large ethnic populations from nations where lamb consumption is more common. Those include Central and South America, the Middle East and the Mediterranean nations.

The U.S. Department of Agriculture reports that 24 percent of the lamb consumed domestically is imported, creating an opportunity for domestic growers to capture a share of that market.

Meyer said the research project might help determine whether Dorper lambs could be a part of that market growth.

Winter Goose Grazing Damages Willamette Valley Crops

Oregon State University researchers studying "overwintering" geese in the Willamette Valley have found that these migratory birds are capable of causing significant damage in valley winter wheat fields.

The study revealed winter wheat yield losses of up to 25 percent in some fields.

Geese landing in field.

Geese grazing in a Willamette Valley wheat field. The number of Canada geese overwintering in the valley has increased dramatically. Photo: Bob Rost

Flocks of geese damage crops by feeding on young winter wheat plants early in the year.

Range scientist Mike Borman, OSU Department of Rangeland Resources, and a department colleague, Doug Johnson, conducted the study along with Mounir Louhaichi, a graduate student in rangeland resources.

Borman stressed that the purpose of the study was not to estimate damage throughout the valley due to goose grazing, but to develop reliable methods farmers can use to estimate the amount of crop damage caused by geese.

"The project employed a combination of Global Positioning System (GPS) technology, aerial photography and yield monitoring systems to form an accurate picture of what happened in grazed fields examined in the study in January, March and April when the highest numbers of overwintering geese were present," said Borman.

GPS uses satellites to produce an accurate map grid of a particular area or field. Researchers used the map grid to identify specific sections within a field and study changes in those sections over time. The aerial photography revealed the extent of changes in crop growth over the field, and yield monitoring equipment installed on harvesting combines provided a picture of how yields fluctuated throughout the field.

In addition, the research team set up "exclosures," or fenced-off plots, in fields.

"The exclosures were protected from goose grazing throughout the winter and provided several points of comparison with grazed areas in the fields," said Borman.

According to Borman, "ground-truthing"-the careful collection of observations by researchers walking through damaged areas-was a key component of the study.

"The aerial photography and yield monitoring only tell us what's going on in the field," Borman said. "To find the cause, you have to go in and take a look.

"In some areas of the fields, poor plant growth and low yields were due to excessive moisture," he said. "In other areas we observed clipped leaves and stalks on plants and the presence of goose droppings. This told us geese had been there and gave some indication of the numbers of birds grazing in the location."

Overwintering geese on valley farmland isn't new, but over the past two decades the number of Canada geese spending the winter in Oregon has shot up from 25,000 to more than 250,000.

"The increase is due, in part, to droughts over the past several years in California where Cackling Canada Geese had wintered until dry conditions made goose forage scarce," Borman said.

In the second phase of the project Borman is studying methods of monitoring goose grazing in grass seed fields in the Willamette Valley. Growers can use these methods to document goose-caused damage.

"The second part of the goose grazing study will be very important because grass seed is a dominant crop in the valley and there is a lot of interest in what we find," said Borman. In particular, more study is needed on the costs of hazing geese, or scaring them away from fields that growers want to protect, he said.

"Currently farmers use sound generating equipment, such as propane cannons, and all kinds of scarecrow-like devices to scare geese out of fields," said Borman. "But these birds are smart. It doesn't take them long to figure out whether a threat is real."

Control of the geese population through hunting is another option that is under consideration.

Funding for the project is provided through a U.S. Fish and Wildlife Service grant.