December 2012 Number 1 - Utah Native Plant Society

Calochortiana December 2012 Number 1
Responses of Colorado Plateau Drylands to Climate
Change: Variability due to Land Use and Soil-
Geomorphic Heterogeneity
Mark E. Miller and Jayne Belnap, U.S. Geological Survey,
Southwest Biological Science Center, Moab, UT
Abstract: Dryland ecosystems comprise well over 50
percent of the Colorado Plateau province and are subjected
to land uses such as livestock grazing, recreation,
and energy development. Low and variable amounts of
precipitation constrain dryland resilience to land-use
activities, making drylands particularly susceptible to
persistent changes in structure, function, and capacity
for providing key ecosystem services such as soil stabilization.
Through multiple effects on soil and vegetation
attributes, land use also mediates ecosystem responses
to climate. Ecosystem responses to interactive effects of
land use and climate vary spatially in relation to soil
geomorphic properties such as texture, depth, horizonation,
and topographic setting due to effects of these
properties on water and nutrient availability, soil erodibility,
and site susceptibility to hydrologic alteration by
soil-surface disturbances. We use existing data from
Colorado Plateau drylands to illustrate these concepts
and to develop a set of testable hypotheses about climate-land-use
interactions (i.e., how climate and land use
each affect ecosystem resilience to the other) in relation
to soil-geomorphic properties. For example, we predict
that climate-land-use interactions in Colorado Plateau
drylands will be greater on deep soils than on shallow,
rocky soils because the former support grasslands and
shrub steppe ecosystems that have been most extensively
used and modified by livestock grazing. We also
predict that climate-land-use interactions will be greater
on relatively fine-textured soils than on coarse-textured
soils because the former tend to be more susceptible to
exotic plant invasions and hydrologic alteration following
disturbance, and because they exhibit greater fluctuations
in resource availability in response to precipitation
variability. Variable ecosystem responses to climate
due to land use and soil have implications for scientists’
efforts to predict ecological consequences of climate
change with sufficient detail to inform management decisions,
and for decision makers’ efforts to prioritize and
evaluate risks of different management strategies.
Colorado Rare Plant Conservation Initiative, Saving
Colorado’s Wildflowers
tage by improving the stewardship of Colorado’s most
imperiled plants. One hundred thirteen native plant species
in Colorado are considered imperiled or critically
imperiled by the Colorado Natural Heritage Program,
meaning they are at significant risk of extinction. Of
these species, 63 are endemic, growing only in Colorado
and no place else in the world. Nearly 50% of our
state’s imperiled native plants are considered poorly or
weakly conserved. Unlike animals, Colorado has no
state-level recognition or protection for plants. Impacts
to Colorado’s rare plants are at an all-time high due to
our rapidly expanding human population. Primary
threats include habitat loss and fragmentation associated
with resource extraction, motorized recreation, housing
and urban development, and roads. Many rare plants are
also at risk due to a simple lack of awareness regarding
their precarious status. Despite the size and scale of
these threats, we still have a chance to make a difference
through strategic conservation actions, since healthy
populations of many imperiled plants still exist. The
goal of the Rare Plant Conservation Initiative is to conserve
Colorado’s most imperiled native plants and their
habitats through collaborative partnerships for the preservation
of our natural heritage and the benefit of future
generations.
Rare Plant Management and BLM Policy
Carol Spurrier, Bureau of Land Management, Washington,
DC.
Abstract: Rare plant conservation continues to be part
of the multiple use mission of the Bureau of Land Management
(BLM) in the United States. With continuing
increases in the demand for all types of energy and other
goods provided by the public lands, as well as landscape
scale changes in natural vegetation due to increased
wildfire and climate change, we wondered if the public
lands that have been designated as part of the Natural
Landscape Conservation System (NLCS) hold significance
for protection of rare plant resources in BLM. We
examined 2006 occurrence data on BLM lands from
NatureServe within NLCS unit boundaries to determine
rare plant species occurring in each unit. In this paper
we discuss our findings for the different types of
designations (wilderness, wilderness study areas, National
Monuments and National Conservation Areas)
within the System.
Brian Kurzel, Colorado Natural Areas Program
Abstract: The Colorado Rare Plant Conservation Initiative
is a diverse partnership of public and private organizations
dedicated to conserving our state’s natural heri-
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