|The 14,000-acre Palos Preserve in Cook
County is perhaps the most famous single natural
tract in the lower Des Plaines region. Cited by
the 1939 WPA Guide to Illinois as a landmark for
hikers, it is known for its seasonal carpets of
wildflowers and its migratory birds.
Yet even here, in this extensive piece of
wildness in the southwest suburbs of Chicago,
the ecological effects of surrounding
urbanization have taken their toll.
Native ecosystems such as oak savanna
and.prairie became degraded because of the
"island" effect of surrounding development and
the absence of fire. Naturalists and ecological
activists determined that active human
involvement was needed to preserve the region's
native plant and animal species. In the early
1980s, volunteers began tending sites in the
Dennis Nyberg, volunteer steward at Cranberry
Slough Nature Preserve in the Palos complex,
says restoration management has dramatically
improved both the appearance and ecology of the
Cranberry Slough area. Volunteers have burned,
trimmed and girdled brush and trees, primarily
to reduce nonnative buckthorn and to re-open
vistas between sedge meadows, wetlands and oak
woodlands, which had become overgrown due to a
lack of fire and invasion of foreign species.
They also planted native spxcies and repaired
eroded natural ponds.
Since the 1980s, Nyberg estimates that he has
visited the site about 50 times each year, for a
few hours per visit. That's typical of the
dedication of many volunteer restorationists. He
feels his efforts paid off when sandhill cranes
returned to nest at the slough in 1998, probably
the first cranes to nest in Cook County since
the Civil War. The impressive birds prefer open
wetlands surrounded by oak savanna, the
19th-century landscape of the slough area,
brought back by restoration.