Geoscience Reference
In-Depth Information
Figure 16-20.
Multitemporal Landsat image based on TM band 4 (near-infrared) for 2006, 2007 and 2009, color
coded respectively as blue, green and red (see Color Plate 16-20). Bright colors represent signii cant changes in
land cover from year to year; dull-gray colors indicate little change in land cover. The broad maroon-purple zone
shows the extent of high water in 2007; black and dark blue show perennial water bodies; compare with Fig.
16-16. CBWA - Cheyenne Bottoms Wildlife Area; TCN - The Nature Conservancy. Image from NASA; processing
following the method of Pavri and Aber (2004), central Kansas, United States.
shorebirds (Birds & Nature 2009), which i nd
food, shelter, and rest in the myriad wetlands
of the region. The main end points for this
migration path are central Canada and the Gulf
of Mexico, but some species travel from the
Arctic to Patagonia.
The Nebraska Sand Hills are now largely
stabilized by prairie vegetation, which has pre-
served the dune forms. The dunes resemble
giant waves on the ocean (Fig. 16-24) and are
comparable to other great sand seas in Africa,
Arabia, Asia, and Australia. Individual large
transverse dunes are typically several kilometers
long, one kilometer wide, and up to 100 m tall
(Keech and Bentall 1978). The dunes appear to
have been active several times during the past
16.2.4 Nebraska Sand Hills
Extensive tracts of sand dunes are common
throughout the central Great Plains and Rocky
Mountains. The greatest among these is the
Nebraska Sand Hills, which cover nearly 20,000
square miles (52,000 km
2
) in north-central
Nebraska and southernmost South Dakota (Fig.
16-23). The Nebraska Sand Hills are the biggest
expanse of sand dunes in the western hemi-
sphere, more than three times larger than the
state of Massachusetts, and one of the largest
areas of native prairie in the Great Plains (Labedz
1990). The sand hills are located along the prin-
cipal route of the North American central or
Great Plains l yway for migrating waterfowl and
