Hi Tweets,

On a CBC scouting mission on Queen Anne Hill yesterday morning I for the
first time took a good look at the ravine on the NE side of the hill (from
the bridge on McGraw St.) and was horrified by the degree to which the
ravine has been taken over by invasive vines. Not even Himalayan blackberry
seems to be competing successfully with the undulating masses of ivy,
clematis and deadly nightshade. All of the trees have leafy green girdles,
and many have fluffy clematis seedheads spewing forth from their crowns.

I had the good fortune to see a female Sharp-shinned hawk shifting among the
vine-laden trees, and among the usual native city-birds (bc chickadee, de
junco, house finch, pine siskin, bushtit, etc.), I found a winter wren
ducking through the ivy.

My questions are these -- obviously this unusual plant community is
currently supporting a moderate number of winter city birds, but left to
itself, will these vines kill everything on which they climb? Once the
shrubs and even trees have been completely eliminated, will bird species
diversity decline? Which species can use these vine mats, or even prefer
them? Is there enough structure to provide habitat for species that nest on
or near the ground? Would rats be a problem? (Cats certainly are -- the
surrounding neighborhood supports an alarming number of free roaming
felines, not to mention seed sources for all these vines and other invasives
should we ever try to launch an attack...). I ask mostly out of curiousity.
I've been involved in a fair number of efforts to remove invasives from
various public places and to plant natives, so I know the ultimate futility
of the exercise (not that it isn't incredibly satisfying on a small scale!)
Given that invasives are here to stay, what level of habitat are they providing?

Katie Sauter
sauter at igc.org