Description and Ecology: Lowland riparian forests border streams as they flow out of the
foothills onto the eastern plains. Plains cottonwoods interspersed with thickets of willows and
other shrubs such as wild plums, hackberries, hawthorns, chokecherries, and box elder generally
line these streams in eastern Colorado. Many of these lowland riparian areas have been
substantially altered by humans to create residential, industrial, and recreational developments and
to create highways and gravel mines.
Various sources report that riparian forests comprise less than 3% of the total landscape, but up
to 80% of the resident bird species use them for some part of their life cycle. Birds use this
habitat for nesting, cover, resting, migration stopover areas, and migration corridors. This system
has the richest avian species component of any of Colorado's habitats. Common species in
lowland riparian forests in Physiographic Area 36 include American Kestrel, Eastern and Western
Screech-Owls, Great Horned Owl, Mourning Dove, Northern Flicker, Western Wood-Pewee,
Western Kingbird, Eastern Kingbird, House Wren, Black-billed Magpie, American Robin, Yellow
Warbler, Blue Grosbeak, and Bullock's Oriole (Andrews and Righter 1992, Krueper 1995, Howe
1996, Kingery 1998).
Importance and Conservation Status: Lowland riparian systems provide dispersal corridors for
woodland birds across otherwise treeless terrain. Well-defined, unique, and highly productive,
riparian areas are sensitive to disturbance (Melton et al. 1984).
Riparian ecosystems are important for both humans and wildlife. During historic times, humans
have used riparian zones intensively and have substantially altered much of this habitat to create
highways, gravel mines, and residential, industrial, and recreational developments. Riparian
zones are convenient locations for those activities. They are also productive areas for domestic
livestock grazing. However, the impacts of domestic livestock are not as dominant as in high
elevation riparian zones (Melton et al. 1984, Wozniak 1995).
Unlike the high elevation riparian habitat in Colorado, much of the lowland riparian ecosystem is
in private ownership; consequently, it is much more susceptible to loss and degradation by urban
and industrial development, mining, road and trail development, and recreational development.
Priority Species Accounts: Two species are identified as high priority in lowland riparian
habitat in Physiographic Area 36: Lewis's Woodpecker and Bell's Vireo.