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Figure 16-12. Overview of the Pueblo, Colorado, saltcedar study site on the Arkansas River l oodplain just below
Lake Pueblo. Ground cover is a patchwork of saltcedar thickets, salt sacaton grass, rabbitbrush and assorted weeds,
and bare sandy soil. Part of the dam is visible across the top of the scene. This site is supervised by the U.S.
Bureau of Reclamation. Kite aerial photo by S.W. Aber, J.S. Aber and D. Eberts (lower left).
immediate success, particularly in arid plateau
canyons and intermontane valleys of Nevada,
Utah and western Colorado. Large tracts of salt-
cedar were cleared from river valleys and willow
are beginning to recover (Bean, Ortega and Jan-
dreau 2009; Dudley et al. 2010).
At the Pueblo study site, ongoing research
focused on the biology and behavior of the
beetles and the effects of their release on
wildlife, saltcedar, and non-target vegetation
(Eberts et al. 2003). Initial release of D. carinu-
lata was successful in defoliating saltcedar
quite well (Fig. 16-13), but the beetles did not
migrate away from the Pueblo site in large
numbers (Bean, Ortega and Jandreau 2009).
Other releases were made subsequently down-
stream along the Arkansas River in southeastern
Colorado. Saltcedar was defoliated in some situ-
ations (Fig. 16-14), but in general beetles did
not become well established in many locations.
The reason for limited success of saltcedar leaf
beetles along the Arkansas River may be attrib-
uted to a couple of factors in particular (Bean,
Ortega and Jandreau 2009):
Figure 16-13. Saltcedar largely defoliated by saltcedar
leaf beetles at Pueblo, Colorado study site. This ground
picture was taken near the end of the growing season
in October 2003, two years after i eld release of the
beetles. Saltcedar bush stands about 4 m high. Photo
courtesy of D. Eberts.
Beetle reproduction is tied closely to length
of summer daylight; at 38° N beetles achieve
only 1-2 generations per summer. At the
home-range latitude, longer summer days
allow three generations per year.
• Predators - birds, other insects, and spiders -
are much more numerous on the semi-arid
plains than in the arid plateau canyons of
• Latitude of
38° N has a shorter summer day
compared with the home ranges of the
beetles imported from central Asia (
44° N).
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