December 2012 Number 1 - Utah Native Plant Society

Calochortiana December 2012 Number 1
trends and supports the idea that the species is reproductive
(data not presented) and recruitment is probably
occurring at these locations. This monitoring project
provided minimal data to inquire into the interactions of
the plant community and resource use within the ecosystem.
The multivariate ordination (NMS) analysis
found interesting relationships between species richness
and penstemon density (Figure 4), although linear regressions
had weak results. We hypothesized that water
is a driving resource in the system and that higher sagebrush
density indirectly reduces species richness and
penstemon density due to its control over the soil moisture
and possibly space and nutrients. Our current data
cannot support this hypothesis, but the initial analysis of
the plant community data found interesting and relevant
interactions that could lead to a better understanding of
the rare species’ population and community dynamics.
Sampling of additional sites and increased measuring of
soil moisture will assist in the development of theories
that relate sagebrush and penstemon densities to the
availability of water and the effects of inter-specific
competition.
The Eagle study site was roller-chopped in the 1980s
to reduce sagebrush cover and improve the system for
grazing. This disturbance may have reduced sagebrush’s
control over soil moisture and provided an appropriate
disturbance for increased recruitment and establishment
of P. harringtonii. An understanding of this ecosystem’s
plant community dynamics and competition for water
may provide clues to improving habitat of the rare penstemon,
especially if the rate of habitat loss continues to
accelerate in this rapidly developing region. If we improve
our knowledge of the resources (water) and processes
(disturbance) that regulate P. harringtonii it may
be possible to develop management and restoration
practices that promote higher density populations of the
species by the manipulation of sagebrush cover and surface
disturbance.
REFERENCES
Buckner, D.L. and J.E. Bunin. 1992. Final report:
1990/91 status report for Penstemon harringtonii
Penland. Unpublished report prepared for the Colorado
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Caldwell, M.M., T.E. Dawson, and J.H. Richards.
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Colorado Native Plant Society. 1997. Rare Plants of
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Elzinga, C.L., D.W. Salzer and J.W. Willoughby.
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BLM Technical Reference 1730-1 (BLM/RS/ST-
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Panjabi, S.S. and D.G. Anderson. (2006, June 30).
Penstemon harringtonii Penland (Harrington’s beardtongue):
a technical conservation assessment. [Online].
USDA Forest Service, Rocky Mountain Region. Available:
http://www.fs.fed.us/r2/projects/scp/assessments/
penstemonharringtonii.pdf [1/7/09].
PC-ORD Version 5.0. 2005. MjM Software, Gleneden
Beach, OR, USA.
Spackman, S., B. Jennings, J. Coles, C. Dawson, M.
Minton, A. Kratz, and C. Spurrier. 1997. Colorado Rare
Plant Field Guide. Prepared for the Bureau of Land
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USDA, NRCS. 2009. The PLANTS Database (http://
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