Other precautions include treating irrigation water with chemicals toxic to fish and amphibians, and setting poisoned bait for rodents.
"The California Leafy Green Hander agreement is transparent, flexible and science based," said Gennet. "Going above and beyond it just creates costs for farmers and doesn't improve safety."
It also creates costs for wildlife. Although scant evidence exists of risk of food-borne disease spread by wildlife, the risk of rejection of produce by major buyers is too much for most growers to bear, say Gennet and her co-authors. They measured changes in wetlands and riverside habitat in the Salinas Valley between 2005 and 2009, finding 13.3 percent converted to bare ground, crops or otherwise diminished. Widespread introduction of fencing blocked wildlife corridors. Low barriers even kept out the frogs.
Unlike the LGMA standards, individual corporate requirements for farm produce are generally not transparent to the public. But in surveys, farmers report pressure from auditors to implement fences and bare ground buffers around spinach, lettuce, and other leafy greens.
Such pressures have set back years of collaboration between growers and environmental advocates to make farm edges slim sanctuaries for wildlife, as well as buffers between agricultural fields and waterways. Fallow strips along streams and rivers provide corridors for migrating animals and birds.
"This is an area that is already 95 percent altered the habitat that remains is critical," said Gennet. "Removing 13 percent of what is already heavily-impacted habitat and cutting off wildlife corridors is a significant loss."
The Salinas River and its tributaries are an important rest stop on the Pacific Flyway, a major migration route for neotropical songbirds, and home to raptors and shorebirds. The waterways are also corridors for deer and other big animals moving between the high country of the Diab
|Contact: Liza Lester|
Ecological Society of America