December 2012 Number 1 - Utah Native Plant Society

Calochortiana December 2012 Number 1
Biogeography and the Evolution of Rare, Endemic
Species: Insights from two Mustard Genera in the
Southwest (Draba and Boechera, Brassicaceae).
Loreen Allphin, Department of Plant and Wildlife Sciences,
Brigham Young University, Provo, UT and
Michael D. Windham, Duke University, Durham, NC.
Abstract: With a growing number of plant species in
danger of extinction due to human induced threats,
species-by-species approaches to management are becoming
unrealistic. Conservation of rare plants would
be improved by a clearer understanding of the evolutionary
forces that give rise to rare, endemic species.
These data might facilitate the development of management
strategies applicable to a wide range of rare species.
For this study we conducted a detailed survey of
species within the genera Draba and Boechera from the
Southwest United States (genera and a region with the
high concentrations of endemic species). We collected
data on geographic distribution, degree of endemism,
chromosome number, ploidy level, breeding system,
reproductive fitness and presumed mode of speciation.
The study revealed some interesting evolutionary and
biogeographic patterns. Some rare endemic species in
these genera were primarily diploid, outcrossing, paleoendemic
species with relatively low fecundity. Conversely,
other endemic species in these groups were primarily
polyploid, autogamous or apomictic, neoendemics
with relatively high fecundity. These patterns appear
to reflect both the type of speciation that occurred and
the geologic/biogeographic history of the region. The
geography of rarity and endemism in these genera appears
to be an expression of primary divergence, reticulate
evolution, and evolutionary time.
Physical and Chemical Characteristics of Xeric Soils
in Eastern Great Basin Determines the Natural Plant
Associations, but Recently Ruderal Species have Become
an Important Factor.
Rodd Hardy, Bureau of Land Management, Salt Lake
City, UT
Abstract: What are major physical and chemical properties
of the soil profiles that are key factors for different
plant associations? What are the major natural plant
associations based on these soil properties? What particular
ruderal species, to what degree, and when did
these invaders become a major role within plant associations
today? What recommendations are needed to mitigate
the impacts of ruderal species to natural plant communities?
This paper will note the ecotone sharpness in
which plant communities in dry climates change from
one type to another for major plant species and the
chemical properties of the soil which determine specific
plant communities. Winterfat and gray molly sites have
particularly been vulnerable to annual grass and goosefoot
forbs, but invasive species effects upon endemic
species such as Pohl’s milkvetch and Small spring parsley
has also been notable.
Predictive Habitat Models for Arctomecon californica
Torrey & Frémont and Eriogonum corymbosum
Bentham var. nilesii Reveal for the Upper Las Vegas
Wash Conservation Transfer Area, Nevada.
Amy A. Croft, Thomas C. Edwards, Jr., Janis L. Boettinger,
Glen Busch, James A. MacMahon, US Geological
Survey and the Ecology Center, Utah State University
Abstract: The Upper Las Vegas Wash Conservation
Transfer Area (ULVWCTA), situated northwest of
Las Vegas, Nevada provides habitat for two of the
state’s special status species, Arctomecon californica
Torrey and Frémont and Eriogonum corymbosum Bentham
var. nilesii Reveal. In an effort to aid the Bureau of
Land Management Las Vegas Field Office in conservation
based decision making, we built a family of statistical
models capable of predicting likely locations of each
species in the ULVWCTA. To predict locations of the
plant species, emphasis was placed on sensitivity, the
ability of the models to predict where the species were
located. A. californica sites were characterized by soils
with low shear and compressive strength values, a low
percentage of rock, and a physical soil crust. The most
common soil type and vegetation association occupied
by A. californica was the Las Vegas type (spring deposits)
and the Ambosia dumosa-Atriplex confertifolia
vegetation association. Models for A. californica had
moderate to excellent predictive capabilities, with accuracies
as reflected by sensitivity ranging from 75% to
95%. Small sample sizes precluded construction of any
models for E. corymbosum var. nilesii. Instead, we were
able to successfully predict likely locations of E. corymbosum
var. nilesii with the A. californica models. Overall,
the models had predictive capabilities of sufficient
accuracy to be used in conservation decisions for the
ULVWCTA.
Comprehensive Interactive Plant Keys for the Southwest
Bruce S. Barnes, Flora ID Northwest, Pendleton, OR
Abstract: Plant conservation and management for any
given locality is a complex process which depends on
reliable and continually updated information regarding
what species are found and where. These critical data
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