Landscape History - Mountains and Plains: The Ecology of Wyoming Landscapes - page 25

1. Bison were present in all parts of Wyoming, includ-
ing subalpine meadows, but they were especially
common on the eastern plains. evidence of heavy
grazing by bison was common.
2. Range fires occurred, but they were not mentioned
often; grazing by native animals may have mini-
mized fuel accumulation.
3. Forest fires were common.
4. Big sagebrush was very common.
5. Grizzly bears, black bears, wolves, and elk were com-
mon in grasslands and shrublands of the basins and
plains but declined with increased hunting pressure.
6. Some streams were ephemeral and had steep-walled
gullies.
7. Grasshopper and Mormon cricket plagues occurred,
as they do now.
8. Vegetation patterns have changed very little since
the mid-1800s.

mer of 1886 and the devastating winter of 1886-1887,
which killed 40-60 percent of the cattle in most of
Wyoming. 62 Vegetation changes caused by livestock in
the late 1800s and early 1900s are difficult to assess,
but they surely were substantial and are still apparent
in some areas (see chapters 6 and 7).
Forests also were subjected to new kinds of human
influences in the 1800s. the Union Pacific Railroad, the
nation's first transcontinental railroad, required rail-
road ties, and lumber and timbers were needed along
the way for new towns and for mining gold, silver, and
copper. the remnants of slab piles can still be found,
indicating the locations of sawmills. Some forests were
essentially clearcut. elsewhere, forests were thinned as
the tie-hackers cut only the trees they wanted. Railroad
ties typically were floated down creeks and rivers to rail-
heads, especially during spring when water levels were
high. Such activity, along with placer mining for gold,
must have caused significant changes along some rivers
and creeks.
the first photographers provided another kind of his-
torical record. Several studies have compared early and
modern photographs of the same areas. For example,
rangeland ecologist Kendall Johnson retraced the route
of William Henry Jackson, the famous landscape pho-
tographer who accompanied the 1870 expedition of
geologist Ferdinand Hayden across Wyoming, which
occurred prior to the cattle boom. 63 Johnson located
and rephotographed 56 scenes in the 1980s, approxi-
mately one century later. the photo comparisons led
him to conclude:

Human influences were minor when the early explor-
ers were writing their journals in the 1800s. 59 Probably
fewer than 10,000 people resided in Wyoming territory
at the time, less than 10 per square mile. However, more
than 350,000 immigrants traveled through Wyoming
along the oregon trail between 1841 and 1868, and
with the wagon trains came thousands of livestock.
these animals grazed along the way and sometimes were
concentrated in small areas. For example, one group of
cowboys worked unsuccessfully for five days to drive its
herd across the Platte River near casper, and during this
time the grass was devoured for miles around. 60 Dur-
ing the 1800s, the environmental impacts of people and
livestock were probably much greater along the oregon
trail than in the region as a whole.
the effect of livestock became more widespread
after the completion of the Union Pacific Railroad in
1869, which made western rangelands a source for
much of the nation's beef, lamb, and wool. Large herds
of cattle were driven northward from texas. Sheep were
imported by railroad, and some herds grew to 10,000
animals. investors and western stock growers became
wealthy. Livestock were forced to graze on marginal
rangelands, leading rangeland scientists John Mitchell
and Richard Hart to write, “the land was filled entirely
with cattle.” 61 Fortunately for rangeland condition,
the livestock boom ended in 1887, following a crash
in the beef market that coincided with the dry sum-

1. except in the relatively small area where the land had
been plowed, the grasslands of eastern Wyoming are
very similar to those of 100 years ago. overall, the
effects of livestock grazing appear not to have been
much different than the effects of native ungulates,
although shifts in plant species composition may
have occurred.
2. Big sagebrush has increased, decreased, or remained
about the same, depending on land use and site char-
acteristics, but it was abundant in the intermountain
basins long before livestock arrived.
3. Woodlands and forests on the uplands have become
more dense, probably because of fire suppression,
but trees have not invaded adjacent vegetation types
over large areas.