Landscape History - Mountains and Plains: The Ecology of Wyoming Landscapes - page 24

0

10

20

Wetter

30

40

Little Ice Age

50

Drier

60

70

800 1000 1200 1400 1600 1800 2000

Year AD

Fig. 2.11. Drought occurrence and duration in the interior
western states during the past 1,200 years based on tree-ring
data collected from sites throughout the region. the hori-
zontal line indicates the average proportion of the western
United States that experienced drought during this time.

Black areas indicate drought. note that the past 400 years
have been relatively moist. Long droughts of at least several
decades occurred before 1300 ad and were more severe than
the droughts of, for example, the 1930s. See also Wise (2012)
and fig. 3.5. Adapted from Gray et al. (2006).

territory, becoming ranchers, farmers, miners, mer-
chants, railroad workers, telegraphers, educators, and
industrialists. 52
the first significant influence of euroAmericans was
through the trapping of beaver in the early 1800s. 53
Such trappers as Wilson Price Hunt, Jedediah Smith,
and Jim Bridger were lured to the region because beaver
pelts were highly valued for the fabrication of felt used
for clothing, primarily men's hats. their unregulated
trapping caused a sharp decline in beaver popula-
tions. Soon, many beaver dams failed—causing soil
erosion and the development of gullies in some areas
where ponds, meadows, and willow-dominated shrub-
lands had existed previously (see chapter 4). Some early
explorers noted how the gullies could be a “madden-
ing hindrance” that would require traveling a circu-
itous route of several miles just to make one mile in the
desired direction—even though the gullies were only
a few yards wide. Dudley Gardner, author and arche-
ologist, suggests that most gullies were the effect of
trapping too many beaver, though he acknowledged
that other factors could have been involved, such as
an increase in wagon traffic and overgrazing by horses
and cattle. 54 notably, the market for beaver pelts dimin-
ished rapidly in the late 1830s. Beaver are now common,
though much less so than previously.
indians had subjected bison and other animals to
hunting for thousands of years, often using cliffs to
kill or trap their prey. the Vore Buffalo Jump, located
along interstate 90 in northeastern Wyoming, is an

outstanding example and was used actively by indi-
ans from about 500 to 200 years ago. 55 Hunting pres-
sure by indians intensified after they acquired horses.
even more bison were killed when the railroad arrived
in 1867-1868, with the tendency of early travelers to
shoot large numbers of animals—part of the adven-
ture. 56 Bison were essentially absent as a free-roaming
animal by the 1880s, about the same time that domestic
livestock herds were increasing. By 1900 the population
of all large mammals (bison, mule deer, whitetail deer,
elk, pronghorn antelope, bighorn sheep, and black and
grizzly bear combined) in Wyoming had been reduced
to as few as 60,000. only with the conservation move-
ment fostered by President theodore Roosevelt and oth-
ers in the early 1900s did natural resource management
improve so that big game populations in Wyoming
could recover. in 2013, the Wyoming Game and Fish
Department estimated that the state was providing hab-
itat for 528,000 pronghorn, 427,000 mule deer, 104,000
elk, 60,000 whitetail deer, 7,400 moose, 5,500 bighorn
sheep, and about 4,000 bison (including Yellowstone
national Park). For comparison, the state had about
576,000 people. 57
A useful approach for determining landscape changes
during the past 100-200 years is to compare present-
day conditions with those described in early journals.
Robert Dorn, noted Wyoming botanist, ornithologist,
and natural historian, summarized salient observations
by trappers, explorers, and settlers in Wyoming during
1805-1878 and concluded the following: 58