December 2012 Number 1 - Utah Native Plant Society

Calochortiana December 2012 Number 1
were chosen to include a range of environmental variability,
growth form, and plant communities. Herbarium
records of known occurrences were used to identify initial
sample sites. We established multiple field sites to
determine the geographic coordinates, environmental
attributes (slope, aspect, soils, parent material) and
vegetation data (associated species) in order to develop
two predictive models for each species: a field key and a
probability-of-occurrence or predictor map. The field
key was developed from environmental attributes and
associated species data collected at the sites and used
only field data. Predictive maps were developed with a
geographic information system (GIS) containing slope,
elevation, aspect, soils, and geologic data – then randomly
tested. Classification-tree (CT) software was
used to generate dichotomous field keys and the maps of
occurrence probabilities. Predictions from both models
were randomly field-validated during the second phase
of the study, and final models were developed through
an iterative process. Data collected during the field validation
were then incorporated into subsequent predictive
models. The models identified potential habitat by
combining elevation, slope, aspect, rock type, and geologic
process into habitat models for each species. The
cross-validated models were >96% accurate and generally
predicted presence with accuracy >60%.
Ute Ladies’-Tresses in the Diamond Fork Watershed:
An Update
Bridget M. Atkin and Steve R. Ripple, BIO-WEST,
Logan, Utah
Abstract: Ute ladies’-tresses (Spiranthes diluvialis)
(ULT) was listed as threatened in 1992. The largest
known population is in the watershed of Diamond Fork
Creek and its tributary, Sixth Water Creek. Between
1916 and 2004, these streams were used as canals, and
they conveyed irrigation water diverted from Strawberry
Reservoir to the Wasatch Front. Increased peak flows
altered the stream channel and aquatic ecosystem, creating
unique conditions that allowed the rare orchid to
thrive. In 2004 a system of pipes was installed to divert
water directly into the Spanish Fork River, thereby reducing
the flows in Diamond Fork and Sixth Water
Creeks. Studies of ULT populations have been conducted
since 1992 under the direction of Utah Reclamation
Mitigation and Conservation Commission. Results
show that ULT colonies are still maintaining large
numbers. However, monitoring of ULT has been difficult.
The unique life-cycle characteristics of ULT, along
with its dynamic habitat, create many challenges.
Highly variable yearly ULT counts are very difficult to
interpret or correlate with environmental parameters. In
2005 other studies were initiated and more associated
plant species data are now being systematically collected
to track changes that may indicate whether the
decreased flows are impacting ULT habitat. During
2007 ULT numbers showed at least two flushes, in early
August with tiny individual plants. Conversely, in 2008
ULT numbers were highest in mid-September and
plants were large. These observations have wide reaching
implications pertinent to many species, indicating
that unless a population is observed carefully, data could
easily be misinterpreted.
Arizona Cliffrose (Purshia subintegra), An Arizona
Endemic
Debra Crisp, Coconino National Forest, Flagstaff, AZ,
and Barbara G. Phillips, Zone Botanist, Coconino, Kaibab
and Prescott National Forests
Abstract: The Arizona cliffrose is a long-lived shrub,
endemic to white Tertiary (Miocene and Pliocene)
limestone lakebed deposits that are high in lithium, nitrates,
and magnesium and is an Endangered species. It
occurs in four disjunct populations spread across an area
of approximately 200 miles in central Arizona. Threats
to Arizona cliffrose include livestock grazing, mineral
exploration, road and utility corridor development, offhighway
vehicle use, urban development and drought.
In this poster we summarize the results of some longterm
monitoring transects initiated in 1987. These transects
are in the Cottonwood population, which is
thought to be the healthiest and contains the most diverse
age structure of the four known populations. Data
on these transects were collected three times, in 1987,
1996 and in 2008.
Demography and Pollination Biology of Graham's
Penstemon (Penstemon grahamii), a Uinta Basin Endemic;
5-year results.
Rita [Dodge] Reisor and Wendy Yates, Red Butte Garden
and Arboretum, University of Utah, Salt Lake City,
Utah
Abstract: Penstemon grahamii is a Uinta Basin endemic
which grows on oil-shale outcrops of the Green
River Formation. Long-term monitoring plots were established
for P. grahamii to collect basic life history
data, study pollination biology, and survey critical habitat.
Research was conducted over 5 years (2004 to 2008)
during May – June, at the Blue Knoll/Seep Ridge and
Buck Canyon population sites located on BLM land.
Data gathered includes rosette diameter, number of inflorescences,
inflorescence height, flowers per inflorescence,
number of fruiting individuals, and herbivory.
The breeding systems study used the following treat-
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