CONFERENCE ABSTRACTS & PRESENTATIONS
* invited presentation
Talk*
CLIMATE CHANGE AND SPRING-FED WETLANDS: MONITORING CHALLENGES AND ANTICIPATED CONSEQUENCES OF DECREASING RECHARGE
SADA, DONALD W. (1); HERBST, DAVID B. (2)
(1) Desert Research Institute, Reno, NV 89509, (2) Sierra Nevada Aquatic
Research Laboratory, Mammoth Lakes, CA
93546
Springs occur where groundwater reaches the surface through natural
processes. Thousands are scattered across the
west in all elevations, geological settings, and landscape settings. Their
environments are highly variable across the
landscape and each spring is distinctive because of many interacting factors
such as discharge, water chemistry,
elevation, aspect, water temperature, persistence, and substrate. These
characteristics are a function of geology,
climate, and aquifer provinence, transmissivity, and size. In arid lands
most springs are isolated and intermittent, and
most large springs lie on bajadas and valley floors.
Predictive models describing species composition of benthic and riparian
communities are problematic because of
isolation, colonization/extinction dynamics, and environmental distinctiveness
of each spring, but work in southern
Nevada and California shows that species richness in aquatic and riparian
communities is correlated with discharge,
communities change from environmentally sensitive and intolerant to tolerant
along a gradient from source to
terminus, and crenobiontics occur only in geologically persistent springs.
Community structure is at the same time
influenced by human and natural factors (e.g., diversion, livestock, drought,
floods).
Springs provide an excellent opportunity to track climate change because
their discharge responds to precipitation,
and they are small and their physical attributes, chemistry, and biota
are easy to sample and monitor. Change can be
tracked at all springs, but natural background variability can be more
accurately and easily documented at persistent
springs that are unaffected by human disturbance (reference condition
springs). These springs are supported by
aquifers with moderate residence time, support relatively diverse aquatic
and riparian communities, and often
inhabited by obligate crenobiontic organisms. Springs that dry frequently
are poor monitoring candidates because
decades are required to determine drying periodicity, and they typically
have a depauperate fauna consisting of
common opportunistic species. Springs supported by regional aquifers are
also poor monitoring candidates because
sources are deep ancient waters with relatively, constant discharge rates,
and do not track contemporary changes in
climate.
Decreased precipitation is anticipated to reduce discharge, which will
alter thermal regimes and reduce spring brook
length, aquatic habitat heterogeneity, and soil moisture. Extent of the
stable environment associated with spring
sources will decrease and the amount of variable environment associated
with downstream reaches will increase.
Aquatic communities near spring sources will change most from being dominated
by crenobiontic macroinvertebrates
to dominance by tolerant forms such as midges and pulmonate mollusks.
In the riparian zone, the extent and cover by
obligatory wetland vegetation will decrease, and facultative and upland
vegetation will increase.
Talk
PERIGLACIAL ACTIVITY ALONG AN ELEVATIONAL
GRADIENT OF GLORIA SITES, WHITE MOUNTAINS, CALIFORNIA
SCHMID, GINGER L.; WILKERSON, FORREST D.
Department of Geography, Minnesota State University, Mankato MN, 56001
This presentation summarizes three to sixteen years of periglacial data
collection in the White Mountains of California
at or near GLORIA sites. In lower elevation GLORIA sites, measurements
of surface activity have been conducted since
2005 with three years of results. In upper elevation GLORIA sites, measurements
of periglacial activity have been
conducted since 1991. Rates of surface activity vary along an elevational
transect running from Sage Hen Flat (3265 m)
to just below the summit of White Mountain Peak (4180 m). Activity at
Sage Hen Flat is minimal, primarily due to
needle ice growth, and is restricted to the surface. Activity rates increase
as elevation increases, with the Mount
Barcroft site showing signs of deeper frost penetration and vertical movement
in small-scale frost boils approaching 8
cm per year. Larger periglacial sorted polygons at Mount Barcroft are
relict and have shown no signs of activity since
1991. The highest elevation sites near the summit of White Mountain Peak
continue to show signs of deep-seated
activity and the summit cone may be underlain by permafrost. All landforms
near the summit, including the largescale
sorted nets, show signs of horizontal and vertical movement that in some
cases approach 10 cm per year.
Although periglacial activity appears to be slowing at all sites below
4000 m, the lack of long-term data at the lowest
sites precludes a definite link between decreasing activity and climate
change at this time.
Talk
POPULATION GENETICS, DISTRIBUTIONAL
MODELING AND CLIMATE CHANGE IN SIERRA NEVADA ALPINE
BUTTERFLIES
SCHOVILLE, SEAN D.
University of California, Berkeley, Environmental Science, Policy and
Management, 137 Mulford Hall #3114, Berkeley,
CA 94720-3114
Rapid changes in ecological conditions have occurred over the past 15,000
years at high elevations in the California
Sierra Nevada. First, the recession and disappearance of alpine glaciers
from elevations above 9,500 feet caused
significant restructuring of alpine communities and impacted the genetic
variation of alpine-adapted organisms.
Second, warming trends and land-use impacts over the last century have
threatened populations of alpine species
even in areas managed as National Forests and National Parks. My research
examines patterns of genetic diversity in
codistributed alpine butterflies to examine the history and structure
of populations in the Sierra Nevada. Alpine
butterflies have genetic patterns consistent with single geographic origins
and recent population expansion across high
elevations in the Sierra Nevada. To highlight priority areas for management
and conservation under climate change, I
develop species distribution models based on environmental data and butterfly
occurrence data. Finally, I examine
how climate records over the last century suggest that declines in alpine
species are likely to have occurred
predominantly in the northern Sierra Nevada.
SCHWARZBACH, STEVEN
Western Ecological Research Center, USGS, 3020 University Drive, Suite
3006, Sacramento, CA 95819
The North American strain of the West Nile Virus (WNV) and the highly
pathogenic H5N1 strain of Avian Influenza are
both recently emerged diseases of birds that claim not only birds but
humans and other mammals as victims. Each
disease has a unique but distinct seasonal pattern that suggests both
weather and bird migrations are important
factors affecting geographic distribution. The Culex mosquito
which thrives in drought conditions is the principal
mosquito host and vector for WNV. WNV first appeared in the western hemisphere
in 1999 in New York City. In 2004
and 2005 it was responsible for mortality events in Sage Grouse on the
east side of the Sierra. Changes in climate and
weather which affect the distribution of Culex mosquitos or amplifying
host birds more resistant to WNV could
theoretically affect the distribution and occurrence of WNV. The H5N1
HPAI virus is largely a disease of poultry that
originated in the rice growing regions of China. The disease has spilled
over into wild birds and in rare cases infected
humans. Qinghai Lake, China, in May 2005 was the site of the first massive
wild bird die-offs due to H5N1 HPAI that
demonstrably did not involve poultry. Nearly 3300 Bar-headed geese, a
species of the Tibetan plateau and a trans-
Himalayan migrant not associated with rice, died in this wild bird outbreak.
Genetic evidence and the temporal
sequence of the infection among different waterbird species at Qinghai
suggested BHGOs were the initial vector, or
alternatively perhaps, only the initial victim. The genotype virus identified
at Qinghai in the May 2005 die-off
subsequently spread to wild birds in Europe then Africa in the fall of
2005. The initial spread to Europe was thought
to be exacerbated by unusually cold weather that pushed migratory birds
along the Baltic flyway in a south- south
west direction earlier than normal. The role of wild migratory birds in
the transmission of the virus is still not fully
understood and is a subject of ongoing research by USGS and many others.
The future spread of HPAI has been the
subject of much speculation and has inspired a national surveillance program
in the United States and Canada where it
still remains undetected. The role of changing climate in the future spread
of HPAI is unknown but most likely will be
related to effects of climate upon patterns and timing of avian migration.
Talk*
BIRD CONSERVATION, RESOURCE MANAGEMENT,
AND CLIMATE CHANGE
SEAVY, NATHANIEL (1,2); GEUPEL, GEOFFREY (1); HERZOG, MARK (1); MOSS,
STELLA (1); STRALBERG, DIANA (1)
(1) PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954,
(2) Information Center for the
Environment, University of California, Davis, CA 95616
The conservation of wildlife populations and their habitat is one component
of natural resource management. PRBO
Conservation Science has worked in the Eastern Sierra to use avian science
to inform the management and restoration
of bird habitats. Today, climate change has the potential to make fundamental
changes to the many aspects of the
ways we manage natural resources. As part of a new initiative, PRBO is
working at the interface of resource
management, climate change, and bird conservation. In the past, we have
used suites of bird species to serve as
indicators of successful management. Today, we are working to understand
whether or not these species will still
persist as the climate changes. In the past, we investigated riparian
restoration to evaluate our ability to return bird
populations to their historical condition. Today, riparian restoration
is important because it provides connectivity and
thermal refugia that will help make ecosystems resilient to climate change.
In the past, we monitored bird
populations to understand local changes in habitat conditions. Today,
we monitor bird populations to understand
global changes in climatic conditions. Our preliminary results suggest
that climate change will pose major challenges
to our historical approach to resource management and bird conservation.
Talk*
CLIMATE CHANGE AND HIGH ELEVATION AMPHIBIANS
AND REPTILES IN THE SIERRA NEVADA
SENDAK, CARRIE M.; MATTHEWS, KATHLEEN R.
USDA Forest Service, PSW Research Station, Albany, CA 94701
Climate change is predicted to impact high elevation aquatic habitats
by decreasing the amount of precipitation
falling as snowpack, the timing of snowmelt, and increasing air and water
temperatures. These predicted changes
will likely have dramatic effects on the amphibians and reptiles in the
eastern Sierra Nevada, however species will
respond differently due to their specific habitat requirements and life
histories. Amphibian and reptile populations in
the Sierra Nevada are especially vulnerable to climate change impacts
because their populations have already
declined, and are subject to other stressors such as disease, pollutants,
and exotic trout. Amphibians and reptiles are
ectothermic and therefore sensitive to changes in temperature and water
availability, and their different life history
stages (eggs, tadpoles, and adults) have different requirements for water
and temperature. Current research in Kings
Canyon National Park documented significant declines in Sierra Nevada
yellow-legged frog recruitment in low
snowpack years; lower snowpack is predicted to increase under climate
change scenarios. All life history stages (eggs,
tadpoles, and adults) of Sierra Nevada Yellow-legged Frogs are closely
tied to aquatic habitats and may be most
vulnerable to changes in water availability. Moreover, their tadpoles
require 3-4 years of permanent water for
metamorphosis, so tadpoles die if lakes dry. Other common eastern Sierra
amphibians including adult treefrogs and
Yosemite toads typically only visit aquatic habitats during breeding and
then move to more terrestrial, upland
habitats, so they may be less affected by changes in water availability.
The distribution and abundance of high
elevation mountain garter snakes are affected by amphibian populations
so garter snakes will decline if amphibians
are adversely impacted by climate change. In addition to understanding
the impacts of climate change on amphibians
and reptiles, it will be crucial to determine the interaction with other
stressors—exotic species, pollutants, disease,
etc.
SKILLMAN, JOHN B (1); SAGE, ROWAN F (2); MEYER, ARCHIE (1)
(1) Department of Biology, California State University, San Bernardino,
Ca 92407, USA. (2) Department of Ecology and
Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
Climate change-mediated altitudinal shifts in the distribution of many
montane C3 species are well documented.
Comparable changes for C4 species remain unreported. Ecophysiological
theory predicts performance tradeoffs
between C3 and C4 plants will depend upon both partial pressures of atmospheric
CO2 and daytime air temperatures.
C4 plants should be favored under low CO2 and/or at warmer temperatures
while the opposite conditions should favor
C3 plants. CO2 and temperature decline with elevation and, at present,
most C4 species are restricted to lower
elevations in all major cordilleras. Thus, temperature currently plays
a predominant role in shaping the
photosynthetic makeup of plant communities along elevation gradients.
But increasing CO2 and temperature due to
climate change may alter the relative performance and/or altitudinal limits
of C4 plants in montane ecosystems. The
grass Muhlenbergia richardsonis holds the high elevation record
for any C4 species in North America, reaching nearly
4000 meters in California's White Mountains. We have examined regional
climate and herbarium records for
M. richardsonis and co-occurring C3 grass species to see if there
is evidence for differential elevation shifts
between C4 and C3 species plausibly attributable to recent climate change.
We have also conducted surveys on leaf
stomatal density, nitrogen concentration, and carbon isotope composition
on M. richardsonis and cooccurring
C3 grass species along a 3000-3800 meter elevation gradient in the White
Mountains. These foliar traits can
provide insight into how elevation-dependent co-variation in CO2 and temperature
affect plant carbon gain limitations
and whether this differs between C4 and C3 species. Our findings provide
limited evidence that M.
richardsonis has recently moved upslope while reference C3 species
have not. Foliar trait data are consistent with the
hypothesis that C4 plants are photosynthetically pre-adapted to the CO2-poor
atmospheres of warming Alpine habitats.
C4 species may become frequent in future Alpine plant communities.
SLATON, MICHÈLE R.
National Park Service, Death Valley National Park, Death Valley, CA 92328
Inyo County contains at least 12 isolated mountain ranges with 6000
ft. or more relief, which offer an ideal setting for
replicated studies of vegetation patterns along elevation gradients, and
potential shifts with climate change. Largescale,
30-year record climatic grids were created for this study area, and summarized
for map units of individual
vegetation communities, ranging from creosote shrublands below sea level,
to mixed desert shrublands and sagebrush
steppe, forested lands, and alpine communities at over 14,000 ft. Estimates
for changes in available land area for
these communities under predicted temperature regimes are given, and generally
indicate reductions in area for
communities at higher elevation, but expansion for some communities at
low elevations. Geomorphologic and
substrate constraints significantly reduce land availability for many
communities, such as specialized shrublands and
herbaceous vegetation types. Biophysical changes in temperature, pressure,
and solar radiation with elevation result
in disproportionately greater increases in temperature and water loss
for communities at higher elevations under
predicted climate regimes, and may result in accelerated changes in those
areas.
Talk*
CLIMATE-INDUCED ELEVATION SHIFTS IN A SIERRA
NEVADA FOOD WEB: HOW DO THE PREDATORS RESPOND?
SMILEY, JOHN
University of California White Mountain Research Station, 3000 E. Line
St., Bishop CA 93514
During the past few decades, climate in the Sierra Nevada Mountains of California has warmed enough to produce earlier snowmelt and a longer growing season at subalpine and alpine elevations. A long-term study of the willow leaf beetle Chrysomela aeneicollis (Coleoptera: Chrysomelidae) has revealed a marked upward shift in elevational range, such that local populations at lower elevations have gone extinct while new populations have been established at high elevations. The overall average upward shift is on the order of 300m (1000’). Approximately 1/3 of summer mortality on the beetles can be attributed to the hunting wasp Symmorphus cristatus (Hymenoptera: Vespidae). This wasp feeds its young exclusively by provisioning its nest with 3rd instar larvae of the willow leaf beetle. Wasp nesting behavior was observed between 1998 and 2008 at two sites: a 2925m site where willow leaf beetles became locally extinct in 2004, and a 3230m site where the leaf beetles maintained healthy populations throughout the study. Between 1982 and 1999, wasps were absent from the 3230m site, but in 2000 began gradually increasing their numbers, becoming common by 2004. Mean hunting time, a measure of how long it takes to find leaf beetle prey, was found to be inversely related to prey abundance, and became longer and longer as the prey became locally extinct at the 2925m site. By 2006, wasps had abandoned the 2925m site completely. By contrast, mean hunting time at the 3230m site was short (~15 minutes) during and after 2004. By 2007 the upward shift appeared to be complete, with hunting times and other parameters at 3230m being approximately what they were at 2925m in 1998. The predator, like its prey, experienced an average upward shift of about 300m.
Talk*
MONO LAKE, RESTORATION, AND CHANGING CLIMATE
SPIVY-WEBER, FRANCES
California State Water Resources Control Board, Redondo Beach, CA
State Perspective on Changing Climate Issues that affect Mono Lake and
Mono Basin Restoration: The State Air
Resources Board will complete its scoping plan for reducing ghg emissions
at the end of 2008, which will be followed
by 1-2 years of implementation actions, both incentives and regulations.
At the same time the State is ramping up its
work on adaptation to climate change with a California EPA report to the
governor and legislature in late 2008. All
State agencies are engaged in both processes, and those that work closely
with Mono Lake--State Water Board, Fish
and Game, State Lands, Air Board--can consider incorporating research
and restoration programs at the Lake and in
the region into California response to climate change.
Talk*
ALPINE MEADOWS, SIERRA NEVADA BIGHORN
SHEEP, AND WILDERNESS: WILL CLIMATE CHANGE IMPACT RECOVERY?
STEPHENSON, THOMAS R. (1,2); GREENE, LACEY (1,2); KONDE, LORA (1)
(1) California Department of Fish and Game, 407 West Line St., Bishop,
CA 93514, (2) University of Montana,
Missoula, MT
Sierra Nevada bighorn sheep are a federally endangered species that
spends most, and in some cases all, of the year
in the alpine. Sierra bighorn are dependent upon, and well adapted to,
a landscape above 11,000 feet during both
summer and winter. Vegetation that provides forage for bighorn is limited
in the alpine of the Sierra Nevada. The
seasonally arid climate characteristic of this range results in minimal
precipitation during the growing season.
Although of limited distribution in the alpine of the Sierra, meadows
provide an important source of forage biomass
and nutrients for bighorn sheep. Many of these alpine meadows are fed
by permanent snow fields that are in decline
as a result of a warming climate. Advances in tree-line also may result
in the eventual loss of alpine habitat.
Consequently, some alpine meadows are at risk of disappearing or at least
drying and senescing earlier in the growing
season. If meadow systems disappear in the alpine, the ability of the
Sierra Nevada to support bighorn sheep will
decline and recovery may be hampered. We used logistic regression and
resource selection functions to quantify use
of alpine meadows by bighorn sheep in the Sierra Nevada. We examined the
use of these meadows on a monthly basis
and among herd units. Sierra Nevada bighorn sheep are an umbrella species
that represents the health and landscape
integrity of the Sierra Nevada; they are dependent upon a contiguous,
expansive wilderness landscape. In addition to
the necessity of alpine habitats, bighorn sheep populations are most productive
when they use lower elevation (<8,000
feet) winter ranges. In some regions of the Sierra Nevada, forest cover
reduces the potential for bighorn to use lower
elevation ranges. Prescribed burning is proposed to remove forest cover
and create the open habitats preferred by
bighorn sheep. Such management actions will increase the likelihood of
recovery of this endangered animal. Yet in
some areas, prescribed burns need to occur within wilderness.
Plenary Talk*
ADAPTIVE MANAGEMENT; OPPORTUNITIES AND CHALLENGES
IN MANAGING ECOSYSTEMS UNDER CHANGING CLIMATES
STINE, PETER A.
USDA Forest Service, Sierra Nevada Research Center, 1731 Research Park
Dr., Davis, CA 95618
Climate Change presents significant challenges to all sectors of our
society. In a landscape of dire predictions and
with a partially skeptical public there is a need to offer options that
give us direction for a constructive future. The
scientific community needs to come forward with solutions amongst the
throng of discouraging problems that are
being reported. In the land management arena there are clear roles for
the professional manager and researcher to
take in making a contribution. There are both adaptation and mitigation
options that are worthy of exploration.
Given the uncertain future these options need to be explored in an active
adaptive management approach in a
partnership between research and management. Examples of the new partnership
in the Southern
Sierra will be discussed.
Talk*
TIMING AND MAGNITUDE OF LATE PLEISTOCENE
AND HOLOCENE GLACIATIONS IN YOSEMITE NATIONAL PARK
STOCK, GREG M. (1); DÜHNFORTH, MIRIAM (2); ANDERSON, ROBERT (2);
KESSLER, MARK (2); DEVINE, PETE (3)
(1) Division of Resources Management and Science, Yosemite National Park,
El Portal, CA 95318 (2) Institute of Arctic
and Alpine Research, University of Colorado, Boulder, CO 80309. (3) Yosemite
Association, El Portal, CA 95318
We mapped the extent of the Tioga (Last Glacial Maximum) glaciation
in Yosemite National Park using a combination
of field mapping, LiDAR data acquistion, geochronology, and numerical
modeling. Results tend to confirm previous
mapping by Matthes (1930) and Wahrhaftig (unpublished), with slight adjustments
in the Tuolumne drainage. U/Pb
dating of granitic boulders along the rim of Yosemite Valley confirms
the presence of an early (Sherwin?) valley-filling
glaciation. Boulders on Tahoe moraines yield cosmogenic beryllium-10 exposure
ages of >100 kyr. Boulders on Tioga
terminal moraines in Yosemite Valley yield exposure ages of ~22 kyr, and
boulders on lateral moraines in the Merced
and Tuolumne canyons yield exposure ages of 19-21 kyr. Exposure ages of
polished bedrock surfaces suggest that the
Tioga deglaciation began ~19 ka and was complete by ~10 ka. At present
there are no confirmed glacial deposits of
Younger Dryas age in Yosemite National Park.
Matthes (Little Ice Age) glaciers in Yosemite National Park have retreated
substantially since their maximum extent
circa 750 yrs. B.P. This retreat has important implications for river-dependent
ecosystems downstream. We are
monitoring the retreat of the Lyell and Maclure glaciers by reoccupying
photo points established as early as 1880,
resurveying cross-glacier transects established in the 1930’s, and
mapping the glacier terminus with GPS. Recently
acquired LiDAR data allows for more accurate volume calculations in the
future. Future work will include field and
numerical assessments of glacier mass balance and predictions of future
water yield in light of projected warming.
Plenary Talk*
INDICATIONS FOR PRESENT AND FUTURE MANAGEMENT
FROM PAST GREAT BASIN CLIMATE AND VEGETATION CHANGE
TAUSCH, ROBIN J.
USDA Forest Service, Rocky Mountain Research Station, Reno, NV 89503
Arid and semi-arid ecosystems of the Great Basin have recently seen
major changes in response to climate and other
human driven environmental changes that represent important management
challenges. From both vegetation data,
and other proxy data, centennial scale climate oscillations have occurred
across the Holocene, and similar changes are
possible in the future. Sensitivity of Great Basin vegetation to these
past climate changes has been consistent over
the Holocene, particularly in response to drought. The associated changes
resulting from the repeated drought cycles
in particular, have provided important information on the kinds of vegetation
changes that are possible in the Great
Basin in response to significant changes in climate. It is the understanding
of the relationships between these
Holocene climate changes and the associated vegetation changes that can
help management to anticipate future
vegetation changes. The patterns and rates of change in Great Basin piñon-juniper
woodlands over the last 150 years
provides an example of the speed and landscape scales at which climate,
and human driven changes in environmental
conditions, can drive landscape scale ecosystem changes. The major challenge
for management is that, combined
with the increasing presence of exotics, these climate and environmentally
driven changes can result in permanent
alteration of the affected ecosystems.
Talk*
INTEGRATED MANAGEMENT FOR CLIMATE IN
THE EASTERN SIERRA NEVADA
UPCHURCH, JIM
USDA Forest Service, Inyo National Forest, Bishop, CA
no abstract submitted
Talk*
WILDERNESS LAW AND POLICY IN A TIME OF CLIMATE
CHANGE
VAIL, JEFFREY
USDA Forest Service, Wilderness and Wild and Scenic Rivers, Pacific Southwest
Region, Vallejo, CA
I will present an overview of Wilderness law and policy, particularly
describing the definition and purposes of
wilderness. Relying upon the definition and purposes for which wilderness
areas are to be administered, I will discuss
how wilderness may be particularly well-suited to assess the consequences
of climate change on our natural resources
and the options and limitations to mitigating effects of climate change
in wilderness. I will discuss briefly how
determinations of wilderness character and maintenance of wilderness in
its untrammeled, natural condition may be
impacted by a changing climate. Finally, I will offer two alternative
scenarios for management response to the impact
of climate change on wilderness to encourage reflection regarding the
appropriate stewardship approach to changing
wilderness conditions resulting substantially from human activities occurring
outside of wilderness areas.
Talk*
A RANGE-WIDE MODEL OF NIGHT-TIME TEMPERATURE
INVERSION BASED ON HOURLY TEMPERATURE DATA
VAN DE VEN, CHRISTOPHER (1); WEISS, STUART B. (2); ERNST, GARY (3)
(1) Albion College, Albion, MI, (2) Creekside Center for Earth Observation,
Menlo Park, CA 94025, (3) Stanford
University, Stanford CA 94035
Plants respond to a warming climate by shifting their distributions
to cooler areas. Typically, this results in an
upslope migration, but it can also result in shifts across aspects (such
as from south- to north-facing slopes).
However, in the case of many mountain-slope valleys, plants have responded
by moving downslope toward valley
floors. We suggest that they are responded to less severe night-time cold
air drainage into those valleys. To
understand the magnitude, timing, and pattern of the cold air drainage,
we have deployed temperature data loggers
throughout the Crooked Creek valley and selected surrounding regions within
the White Mountains, CA. From late July
to early October, 35 thermochrons recorded hourly temperature in 2006,
70 were deployed in 2007, and 98 deployed
in 2008. Although the 2008 data have not been analyzed yet, the previous
data showed significant night-time
temperature inversions, frequently with valley floors 7°C cooler than
adjacent ridge tops, a few hundred meters
higher in elevation.
Using the 2006 temperature data, a 10m digital elevation model (DEM),
and data from long-term weather stations, we
modeled the night-time minimum temperatures across the range. Using multiple
least-squares regression, deviations
from the local weathers station were predicted for the Crooked Creek valley
using topographic position (the local
elevation minus the average elevation within a 500m radius), slope, and
the absolute value of topographic position
(r2=0.92). Using the same variables embedded with the overall lapse rate,
these results were extrapolated across the
rest of the White Mountains, showing similar patterns and magnitudes of
night-time temperature inversions. As
regional temperatures increase, the cold air draining down these valleys
also are become less cold, allowing
bristlecone pine (Pinus longaeva) and limber pine (P. flexilis)
to become established downslope, closer to the valley
floors, a pattern that has been observed in the field and in airphoto
analyses.
Talk*
IMPROVING MEADOW HEALTH IN THE FACE OF CLIMATE CHANGE
Meadows in the Sierra Nevada are particularly at risk of the impacts
associated with climate change as they have
experienced significant degradation in the past 150 years. In this presentation,
I will summarize the historical impacts
to meadow health such as grazing, invasive species, and shrub encroachment.
After reviewing the condition of Sierra
meadows and meadow residents, the current efforts to improve meadow health
in the Sierra
will be discussed. Finally, I will address the challenges to improving
or buffering Sierra meadows to adapt to climate
change.
VORSTER, PETER (1); REIS, GREGORY (2)
(1) Consulting Hydrologist, Oakland, CA, (2) Mono Lake Committee, Lee
Vining, CA
State Water Resources Control Board Decision 1631 and Orders 98-05 and
98-07 used the historic hydro-climatology of
the mid to late 20th century in a deterministic water balance based forecast
model to determine future lake levels and
allocate in-stream flows and exports. Similarly the Los Angeles Department
of Water and Power (DWP) relies on
historic hydrology to guide operations and the implementation of these
decisions. We examine the climate change
impact on lake evaporation and stream runoff and the near and long-term
management challenges that it poses. Even
with no change in average precipitation and runoff, increasing temperatures
and greater evaporation rates translate
into a longer transition period at the current reduced export levels while
the lake rises to the trigger level of 6391 ft
and less exports on average as the lake fluctuates around that level.
The current lake level is lower than what the
models forecasted and it will take an abnormally wet period to achieve
the 6391 ft level by 2014- the year that the
State Board will determine if any revisions to its decisions are warranted
if that level has not been achieved. Further
analysis will indicate how much of the discrepancy is due to model error
and how much is due to climate change.
Likewise higher temperatures during the winter and spring change the timing
and possibly the magnitude of peak
snowmelt runoff. Already earlier than expected snowmelt peaks have created
operational challenges for DWP in its
management of peak flows on Lee Vining Creek. Modification of the post-snowmelt
season hydrograph may be needed
for other ecosystem management needs such as riparian recruitment and
stream temperatures.
Talk*
CLIMATE CHANGE AND DESERT BIGHORN SHEEP:
THE DEVIL IS IN THE DETAILS
WEHAUSEN, JOHN D (1); CLINTON W. EPPS (2)
(1) White Mountain Research Station, 3000 E. Line St., Bishop, CA 93514,
(2) Oregon State University,
Department of Fisheries and Wildlife, Corvallis, OR 97331-4501
Projecting the effects of climate change on wildlife species requires
a detailed understanding of ecological
causal networks that link precise climatic variables with key demographic
parameters that drive population
dynamics. Desert bighorn sheep in California are a model species to examine
this question because longterm
data bases needed to make such analyses exist. Deserts are water limited
ecosystems. For bighorn
sheep populations in the Mojave Desert of California, population dynamics
substantially reflect the
influence of late winter and spring nutrient intake on lamb survival.
Variation in that nutrient intake is
driven by the amount of rainfall in the cold season (October-April). Within
that season, rainfall in certain
months is most influential, with different periods acting independently
through influences on different
forage classes (annual vs. perennial plants). The influence of temperature
on diet quality also varies with
month. Early in the cold season warmer temperatures improve nutrient intake
for bighorn sheep by
accelerating the production of new forage growth when it is temperature
limited. In contrast, later in the
growing season the opposite is true because warmer temperatures hasten
the end of the growing season by
accelerating the loss of soil moisture. A key implication of these details
relative to climate change is the
need for regional projections of this change to have adequate precision.
For the Mojave Desert, climate
projection models agree that temperatures will rise, but disagree on how
much. They also disagree on
whether rainfall will increase or decrease. In short, those models are
inadequate of allow a meaningful
prediction of potential effects on bighorn sheep populations. Long term
climatic data will be examined
instead for trends in key variables.
Talk*
UP, DOWN, AND SIDEWAYS: COMPLEX RESPONSES
OF PLANT SPECIES TO CLIMATE CHANGE IN THE WHITE MOUNTAINS
WEISS, STUART B. (1); VAN DE VEN, CHRISTOPHER (2); ERNST, GARY (3)
(1) Creekside Center for Earth Observation, Menlo Park, CA 94025 (2) Albion
College, Albion, MI, (3) Stanford
University, Stanford CA 94035
The migration of montane plant populations in response to climate changes
is mediated by complex topography and
geologic substrate. Complex environmental gradients in the White Mountains
in eastern California produce striking
variation in vegetation composition over short distances, dominated by
the effects of elevation on temperature and
precipitation, but more locally modified by gradients in potential insolation,
slope, topographic position, and diverse
geologic substrates including carbonate, metaclastic, and granitic rocks.
We built and validated predictive models of
plant species distributions at a scale of 50 m using multivariate statistics,
and predicted future distributions by
assuming that warming trends correspond to changes in effective elevation
(3ºC = 500 m). The ascent of species into
diminishing areas at higher elevations creates the “mountaintop
squeeze” scenario, and several high alpine plants
appear vulnerable to being forced off the highest mountain peak (4340
m) with moderate warming (3ºC). Geologic
substrate constrains species as well, so dolomite specialists cannot advance
to the highest elevations that are
dominated by granitic rocks.
This scenario is complicated by the complex reality of topoclimatic
variation in the White Mountains. Sharp gradients
in minimum temperatures occur with cold-air drainage into valleys, and
downward movements of pine populations
have been documented. Maximum temperature gradients exist across changes
in aspect, so species may migrate
laterally across canyons and ridges from south- to north-facing slopes.
Differing migration rates will lead to new plant
assemblages – at their upper elevation limit, pinyon pines are advancing
into limber-bristlecone forests. The
migration of species such as nitrogen fixing mountain mahogany and soil-forming
dwarf sagebrush, may greatly affect
soil properties. These complexities require detailed field mapping of
species distributions and demography at range
limits, coupled with direct measurements of temperatures, to detect varied
responses to climate change.
Plenary Talk*
STRATEGIC APPROACHES OF THE NATIONAL PARK
SERVICE FOR ADAPTING TO CLIMATE CHANGE
WELLING, LEIGH
USDI Park Service, 1201 Oakridge Drive, Fort Collins, CO 80525
Ecosystems and species will change as climate changes, forcing managers
to consider new strategies for resource
protection. What are the best strategies to adopt in the face of unprecedented
and highly consequential changes that
cannot be accurately predicted or controlled? A number of activities have
been initiated over the last couple of years
to help prepare and guide National Park Service managers in coping with
climate change. However, much work
remains if parks are to develop and implement an effective strategy for
moving forward on this issue. Examples of
some current approaches and actions will be given, including policy, planning,
mitigation, adaptation, and
communication efforts. These will be used to foster discussion and gain
feedback on the challenges and opportunities
climate change presents for natural and cultural resources management.
WENK, ELIZABETH; DAWSON, TODD
Department of Integrative Biology, 3060 Valley Life Sciences Building,
University of California, Berkeley, CA 94720-
3140
In a community of alpine tundra plants from the Sierra Nevada, some
species are widespread, occurring across all four
substrates studied: diorite, granite, hornfels, and marble. Other species
are restricted to fewer soil types. We
collected seeds from 12 species and performed a reciprocal transplant
experiment in growth chambers using native
soils. Eleven species germinated and established equally well across all
soil types, indicating substrate chemistry did
not alone determine species field distributions. However, two patterns
emerged that may contribute to our
understanding of species composition and dominance across substrates.
First, species more dominant on the drier
substrates reached at least half their total germination within two weeks
of planting. Species more dominant on the
wetter substrates required a longer period in wet soil to germinate. Second,
there is a strong correlation between
species relative abundance and percent germination, indicating that high
percent germination may contribute to some
species’ dominance. In the field, germinants were only observed
during an unusually wet summer, indicating
germination is a rare and water-limited event. If growing season rainfall
decreases in the Sierra Nevada, less
germination is expected and species requiring long periods of wet soil
are expected to be disproportionately affected.