Landscape History - Mountains and Plains: The Ecology of Wyoming Landscapes - page 26

4. River bottoms have changed dramatically, caused
by impoundments, irrigation, cultivation, livestock
grazing, and settlements; and some river margins
now have more trees than in 1870. 64
5. Areas of sparse plant growth, such as desert shrub-
lands, retain a nearly identical appearance to those
of 1870.

agricultural purposes, often accelerating erosion. Live-
stock have replaced bison almost everywhere, and many
plant species have been introduced from other conti-
nents, some becoming invasive weeds. towns, cities,
highways, coalmines, oil and gas fields, refineries, wind
energy projects, power lines, dams, and reservoirs have
been built. Riparian landscapes and some grasslands
and forests have been altered most dramatically; trees
have been planted where there were none before. Some
industrial impacts have accelerated to alarming rates in
the past 20 years, especially in the intermountain basins
and western Great Plains. Still, many parts of Wyoming
and nearby states are little changed since American
indians first encountered white-skinned explorers from
the east.

Photographs must be used cautiously in drawing con-
clusions, as they only provide snapshots in time of a
small area. 65

Since Wyoming became a state in 1890, changes have
continued to occur. Forest landscapes in many areas
have been fragmented by road building and timber
harvesting, and some rangelands have been plowed for