Does Riparian Restoration Harm Walnut Orchards?
Researcher:
Suzanne Langridge
Doctoral student
UC Santa Cruz
E.: sml@ucsc.edu
T.: (831) 459-3902
Relevant Links:
Tools:
Revised:
July 1, 2008
A codling moth ruins a walnut.
July 1, 2008
Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334
Could restoring riparian lands near walnut orchards in the Sacramento River Valley increase the problem of agricultural-pest birds and insects? According to a CALFED Science Fellow, the preliminary answer is, "No."
Suzanne Langridge, a doctoral student at UC Santa Cruz, compared the prevalence of pests at 23 walnut orchards with nearby varying amounts of riparian habitat and found that the abundances of agricultural-pest birds, such as the American crow, Brewer's blackbird and European starling, are lower or unaffected by the amount of surrounding riparian wilderness.
Two major walnut cretins, the navel orangeworm and codling moth, were also observed to be slightly less common at farms with greater proximity to restored habitats.
She is currently investigating the links between riparian habitats and the numbers of insect-eating birds and pest insects. So far, she reports that farms with more surrounding riparian habitat are also home to more insect-eating birds.
"Farmers are concerned about more pests coming into their orchards because of restoration," she says. "The issue has come up over and over and is a reason some farmers have opposed restoration along the Sacramento River."
"Stakeholders can use my results and move forward," she says.
And, they are doing just that, as her research findings have already been incorporated into a report to the Colusa Subreach Planning Committee and presented to the Sacramento River Conservation Area Forum Technical Advisory Committee. Members of both of these committees have various levels of support for and concerns about the effects of restoring former farmland.
"I hope my research will be some incentive to support restoration in the future," she says.
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