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Introduction: Shrubland Ecosystem
Dynamics in a Changing Environment
E. Durant McArthur
This symposium proceedings is the ninth in a series on the
biology and management of wildland shrubs sponsored by
the Shrub Research Consortium (see inside front cover) and
published by the Intermountain Research Station. The principal co-sponsors, all members of the Consortium, were the
Shrub Sciences Laboratory of the Intermountain Research
Station, New Mexico State University, and the Jornada
Experimental Range/Long-Term Ecological Site (USDA
Agricultural Research Service and National Science Foundation). Contributions emphasize the impact of changing
environmental conditions on vegetative composition especially in the J ornada Basin and Chihuahuan Desert but also
in other parts of western North America and the world.
The symposium consisted of oral presentations, posters,
and a field trip. For convenience, we have divided the
proceedings into five sections: Overview, Vegetation Dynamics, Management, Ecophysiology, and Field Trip. This
volume includes 47 ofthe 68 papers and posters presented at
the symposium, an account of the field trip, and one paper
(Jabbes and others) presented in an earlier meeting, the
Wildland Shrub and Arid Land Restoration Symposium
(Shrub Research Consortium 1993), but not published in the
earlier proceedings (Roundy and others 1995).
Our symposium and these proceedings were intended to
report results, cultivate interest, and stimulate research
and management activities and options in shrubland ecosystems in response to changing environmental conditions. One
constant about environmental conditions is that they change
(Johnson and Mayeaux 1992; Pickett and White 1985; Tausch
and others 1993; Wondzell and Ludwig 1995; Worster 1993;
Wu and Loucks 1995). Driving forces for environmental
change include natural climatic cycles, pest irruptions, catastrophic fires, herbivore population management and dynamics, and soil development, maturation, and erosion.
Human activities throughout history, but especially during
the past few centuries and accelerating to the present time,
are driving environmental changes both on local and global
scales (Cottam 1947; Gates 1993).
Environmental changes, especially climatic changes, for
western North America have been well documented
(Betancourt 1984; Hughes and Diaz 1994; Miller and Wigand
1994; Neilson 1986; Nowak and others 1994; Spaulding and
others 1983). Adaptation oflife to past and projected future
environments is a rich and fascinating area of study, (for
example, Johnson and others 1993; Lande and Shannon
1996; McArthur and Tausch 1995; Smith and others 1995;
Tausch and others 1995). Our symposium and two recent
Interior West workshops (Tinus 1995; Waugh 1994) are
evidence of the continuing need to network environmental
change information to assist in ongoing management and
research plans and decisions.
The Shrub Research Consortium Executive Committee
has tentatively planned two additional Wildland Shrub
Symposia in the next 4 years. Subjects will be Shrubland
Ecotones and Shrubland Genetics. The eight previous symposia dealt with a wide range of shrubland biology and
management issues (Clary and others 1992; McArthur and
others 1990; McArthur and Welch 1986; Provenza and
others 1987; Roundy and others 1995; Tiedemann and
Johnson 1983; Tiedemann and others 1984; Wallace and
others 1989).
Acknowledgments _ _ _ _ _ __
I thank my organizing committee colleagues, Jerry R.
Barrow, Ronald E. Sosebee, and Robin J. Tausch, for their
assistance with all aspects ofthe planning and conduct of the
symposium. Jerry R. Barrow, Kris Havstad, and Valerie
Gamboa were gracious and helpful in making the local
arrangements. New Mexico State University Office of Conference Services personnel Katie Dunford and Carol Floren
superbly publicized the symposium in its advance and facilitated its fruition in every way. Louise Kingsbury and staff
of the Intermountain Research Station Research Information Group have been most helpful in preparation of the
symposium proceedings volume. Various sessions of the
symposium were moderated by Robin J. Tausch, Dean M.
Anderson, Daniel J. Fairbanks, Jannelle L. Downs, W. Kent
Ostler, and Ronald E. Sosebee. The field trip was lead by
Kris Havstead and Reldon Beck with assistance from Jerry
Barrow, Ed Fredrickson, Dale Gillete, Jeff Herrick, Laura
Huenneke, Curtis Monger, Bill Schlesinger, and Walt
Whitford.
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E. Durant McArthur is Project Leader and Supervisory Research
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