Date: 4/8/17 8:00 pm From: Wayne Hoffman <whoffman...> Subject: [obol] Re: Willamette Valley habitats
I grew up in western Oregon - lived southeast of Eugene (Pleasant Hill area) until I was 10 - I remember picking both "Himalayan" and "Evergreen' blackberries, to eat and for pies in my childhood. I do not have much recollection of prevalence, but they were not hard to find in pickable volumes.
One other thought: I wonder if Richard Eddy chose his sites because they had native vegetation, and chose to avoid sites with alien berries? That might have been a logical thing to do, depending on his goals, but if so, we can only conclude that there were enough such sites still around that he could find some, and enough that the warblers were persisting. The landscape might have already had a major presence of the alien terrorists.
On 4/8/2017 7:06:19 PM, Joel Geier <joel.geier...> wrote:
Hi Bruce (& OBOLites),
Thanks for your informed discussion of Eurasian blackberries and their impacts on bird habitats in the Willamette Valley.
About Franklin and Dyrness (1989), I'm inclined to think that they might just have been disinclined to list one of these invasive species, as I remember Himalaya/Armenian blackberries (along with scotch broom) were quite evident along the I-5 corridor when I passed through on a Greyhound bus in May of 1985, and during my subsequent years of residence in the Puget Sound area.
Anyway I agree that the effects on native bird species must be profound. Looking at the PEERJ paper that Doug Robinson cited, at least three of the species that were common in 1952, but not found in 2013 re-surveys of approximately the same areas, would have been negatively impacted by invasion of Eurasian blackberries in the understory. Specifically:
Nashville Warbler (invasion of native understory)
Chipping Sparrow (ditto)
Northern Rough-winged Swallow (overgrowth of river/creek banks nesting strata by blackberries).