Geography Reference
In-Depth Information
years. Ten years before, the trees were cleared and along with them went the
Pacii c wrens, warblers, and thrushes. Now an acre of lawn replaced the dense
growth of lovely salmonberry. Evicted was a rich community of sparrows and
towhees. For the next two years I drove past the lawn daily, and I only twice
saw a bird on it. Always it was a starling. The lawn seemed to me only slightly
greener than concrete, and even pets and children dared not tread upon its
manicured surface.
Gaining perspective on change in subirdia requires an artist's eye and a
scientist's acumen. Fortunately, Jack DeLap possesses both. As a Ph.D. stu-
dent, Jack carefully analyzes annual satellite images to distill changes in the
vegetation associated with urbanization. His artistic talent supports this work
as he uses an electronic pen to highlight and code each pixel of lawn, con-
crete, and forest on the many images. (Jack's original drawings also appear
throughout this topic.) These ef orts put cold statistics to the changes that I
took personally.
Jack discovered that the creation of Seattle's neighborhoods converted
forests to mosaics of built, open, and forested lands. The process of develop-
ment cropped a landscape that was 80 percent forest into one that was half
forest, a quarter grass, and about 20 percent buildings and roads. Where for-
ests once held two water features, now subdivisions supported seven small
ponds. The mixture of land was stunning. Before the start of our study, Jack
measured 384 miles in each subdivision where forest abutted dif erent types
of land (meadows, existing built areas, and the like), but after development,
this “edge” rose by 60 percent to a whopping 650 miles. In our study, most of
the gains and losses of individual bird species could be linked back to this
changing tapestry of subirdia. In some cases one species' success quickly be-
comes another species' nightmare.
