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January 12, 1998

Carol Shennan takes the helm of Agroecology

Carol Shennan

By Jennifer McNulty

For Carol Shennan, the new director of UCSC's Center for Agroecology and Sustainable Food Systems, navigating the sometimes antagonistic worlds of organic and conventional agriculture is nothing new. For nearly three years, she has been at the forefront of a research project that aims to resolve long-standing conflicts among environmentalists, farmers, and hunters in the Tulelake Basin of northern California.

Shennan joined the UCSC faculty this past fall as a professor of environmental studies. She will spend half her time directing the activities of the center, which has an international reputation for innovation in the field of sustainable agriculture. She came to UCSC from UC Davis, where she was an associate professor in the Department of Vegetable Crops.

Shennan's Tulelake work is an ambitious six-year project to develop new land-use strategies that will preserve farming while addressing a steep decline in biodiversity in the Tulelake Wildlife Refuge, a wetlands area that until recently was the country's premier refuge for waterbirds outside of Alaska. Historically, more than 10 million birds passed through the refuge in fall and spring migrations.

For more than 85 years, the at-times competing interests of farmers, birds, and hunters have coexisted on the refuge's 40,000 acres in the high desert region northeast of Mount Shasta near the Oregon border. Over the years, complex irrigation and drainage systems have been constructed to support farming and homesteading in the region. About one-third of the refuge is currently leased to local farmers who grow potatoes, sugar beets, and small grain. Intensive irrigated farming now surrounds the wetlands area on three sides.

Despite human interventions, the wetlands remained a productive bird habitat until the 1960s, said Shennan. Since then, there has been a steep decline in the bird population (last year's migration was the largest of the past 30 years, with almost 2 million birds coming through), as well as significant drops in the number and variety of amphibians and fish. Many believe that water-quality deterioration and changes in vegetation around the shallow lake have reduced the quality of the habitat for nesting birds.

"Agriculture became the immediate suspect," said Shennan, noting that pesticide drift and chemical fertilizers were immediately identified as possible causes of the problems. But even as lawsuits and countersuits were filed, and demands for new farm practices or an all-out ban on farming in the refuge were voiced, extensive studies failed to confirm a link between farming and the loss of environmental quality or water purity.

"No huge, obvious problem was readily identified," said Shennan, and attention shifted from pesticides to habitat changes resulting from stabilization of water levels in the wetlands as part of flood control and regional water management. Much of the wetland has become "degenerate," with dense stands of tule grass creating a virtual monoculture that is unsuitable for birds but is attractive to two of their key predators: coyotes and raccoons.

With a history of antagonism among environmentalists, hunters, and farmers, Shennan said one of the major challenges of the project is devising a land-use management strategy that will reverse the trend of environmental degradation while integrating the needs of the diverse groups.

"We've worked hard to get farmers, federal agencies, and public groups involved in the research process to help us assess the desirability of different management options," said Shennan, who spent a year just talking to people in the area before she proposed a research project. "And of course any changes have to be consistent with national policies regarding refuge management."

With major funding from the U.S. Department of Agriculture and additional support from the U.S. Bureau of Reclamation and the U.S. Fish and Wildlife Service, Shennan's research team has developed a rotation plan that provides for farming and wetlands management on the site. The strategy basically uses agriculture to replicate the boom-and-bust cycles of climatic variation, which haven't taken place since the introduction of modern irrigation and drainage systems, she said.

So far, seven pilot sites of approximately 40 acres each have been established: Three sites are being used to monitor the transition to wetland in a 20- to 30-year "long cycle" that is designed to create diverse, mature marshes; and four sites are on the "short cycle" rotation that encompasses two years of management as seasonal wetlands, one year of continuous flooding, and three or four years of crop production. This cycle allows for the frequent creation of juvenile and seasonal marsh habitat. The next step is to drain a portion of the existing wetlands to establish a long-term farming site, said Shennan.

The tension lies in weighing the interests of the different groups, and although one of Shennan's goals is to make the conflicts explicit to facilitate the final decision-making process, she said "it absolutely comes down to values."

Shennan's team has been collecting baseline data and monitoring behavior of the pilot sites and adjacent areas for three years. The research phase of the project will continue for another three years, after which the implementation phase will begin.

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