sudden oak death = fewer birds

Sudden oak death (SOD) is a recently discovered plant pathogen which prefers cool, damp climates.  It infects many species of trees and shrubs, and is often fatal to oaks.  Since 1995, it has been found in northern coastal California, as well as Oregon, where there is a real threat it will drastically reduce or elimate several species of red oaks. 

A recent study sought to determine how the loss of these trees will impact populations of several oak-dependent bird species: Acorn Woodpecker (Melanerpes formicivorus, left), Nuttall's Woodpecker (Picoides nuttallii), Hutton's Vireo (Vireo huttoni), Western Scrub-Jay (Aphelocoma californica), and Oak Titmouse (Baeolophus inornatus).   The authors used Christmas Bird Count and Breeding Bird Survey data, and used three different scenarios of the extent of loss of Coast Live Oak (Quercus agrifolia), and important and severely impacted species.

The models estimated >50% decrease in mean abundance in the woodpeckers and titmouse, and less severe declines in the other two species.

Models like these tend to be oversimplified, because it is difficult to take into account the complexity of disease, bird, and habitat interactions.  But these estimates are reminiscent of the declines of common bird species following other tree disease outbreaks, such as Dutch elm disease and chestnut blight.  SOD is easily transported on various species of shrubs often found in the nursery trade, and at least two species of eastern oaks are susceptible to SOD. It remains to be seen if this pathogen can adapt to other types of climatic conditions, and threaten eastern oaks and the birds that depend on them.

Click on "continue reading" for resources.

Resources:

• Monahan, W. B. and W. D. Koenig. 2006. Estimating potential effects of sudden oak death on oak-dependent birds. Biological Conservation 127:146-157.
• USFS SOD page, including information on potential for infection in eastern forests
• USDA SOD detection and management
• SOD in Oregon
• SOD research at Sonoma State University

Comments

[Wisecrow]

I didn't know this. Very interesting. And alarming. Thanks for the heads up.

[Jenn]

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