CONFERENCE ABSTRACTS & PRESENTATIONS
* invited presentation
Talk
IMPACTS OF SOIL WATER AVAILABILITY ON TWO
CO-DOMINANT EASTERN SIERRA NEVADA CONIFERS.
ALPERT, HOLLY; LOIK, MICHAEL E.; MCDONALD, MURDOCH A.
Environmental Studies Department, University of California Santa Cruz,
Santa Cruz, CA 95064
The low-elevation distributional limits of Pinus jeffreyi and
P. contorta in eastern California are likely regulated by
precipitation. At the ecotone between the Sierra Nevada conifer forest
and the Great Basin Desert sagebrush steppe,
winter snowfall (which accounts for about 80% of annual precipitation)
decreases abruptly. A shift in the precipitation
regime in this region could create either an upslope or downslope movement
of the ecotone, with implications for
species interactions, habitat quality, carbon storage, and fire risk.
In this study, we examined the impacts of three
simulated snowmelt soil water patterns on P. jeffreyi and P.
contorta seedling growth and physiology. Three-monthold
seedlings of each species were assigned to one of three watering treatments:
ambient water (aH2O),
corresponding to snowmelt from ambient-depth snow pack (15% volumetric
water content [VWC]); plus water (+H2O),
corresponding to water derived from snowpack approximately twice ambient
depth (25-30% VWC); and minus water (-
H2O), corresponding to water derived from snowpack about 80% of ambient
depth (10% VWC). The -H2O treatment
stopped receiving water after three weeks, and the +H2O treatment stopped
receiving water after eight weeks; the
aH2O treatment continued throughout the duration of the 11-week experiment.
Soil moisture and stem diameter were
measured weekly. Whole-seedling photosynthetic gas exchange and stem water
potential were measured at Weeks 3,
8, and 11. Seedling stem growth, stem water potential, and photosynthesis
decreased in the -H2O treatment of both
species after watering was stopped at Week 3. There were no significant
differences in stem growth, water potential,
or photosynthesis for seedlings in the +H2O and aH2O treatments for either
species. These results suggest that
increased soil moisture may not substantially impact factors affecting
seedling establishment in these species, but
that reduced soil moisture availability may impact seedling growth and
physiology in both conifer species and perhaps
restrict overall seedling establishment success at this ecotone.
Talk*
CALIFORNIA CLIMATE ADAPTATION STRATEGY:
WATER SECTOR STRATEGIES.
ANDREW, JOHN T.
California Department of Water Resources, 901 P Street, Sacramento, CA
94236
With the passage and implementation of the Global Warming Solutions
Act (AB 32), California is leading the way in the
mitigation of climate change through reductions in greenhouse gas (GHG)
emissions. In concert with these efforts, the
California Resources Agency http://www.resources.ca.gov/ has undertaken
the complicated task of developing
California's first comprehensive Climate Adaptation Strategy (CAS). A
new priority in the climate change arena,
adaptation promises to offer solutions to climate impacts as a result
of past and current emissions. Consequently, our
efforts to adapt to expected climate change impacts through careful planning
and preparation must occur in parallel
to ongoing mitigation efforts. The CAS will have six different Climate
Adaptation Working Groups that will identify and
prioritize climate adaptation strategies on a per-sector basis, including:
1) Oceans and Coastal Resources 2) Water 3)
Biodiversity and Habitat 4) Public Health 5) Working landscapes 6) Infrastructure.
I will present on the efforts of the
Department of Water Resources to incorporate climate change into California
water planning, specifically our efforts
to craft adaptation strategies for the water sector of the CAS.
Talk*
BLENDED SATELLITE & GROUND-BASED SNOW
PRODUCTS FOR HYDROLOGIC PREDICTION IN SIERRA NEVADA BASINS.
BALES, ROGER; RICE, ROBERT; KIRCHNER, PETER
Sierra Nevada Research Institute, UC Merced, Merced, CA 95344
Blending of accurate, fractional snow-covered area (SCA) data, available
from MODIS satellite at 500-m resolution,
with spatially representative ground-based snow depth and water equivalent
point data, provides a measurementbased
estimate of distributed snow water equivalent (SWE). Unfortunately, the
current operational network of snow
pillows and snow courses fails to provide the spatially representative
measurements needed for this product. We are
implementing multi-scale, ground-based measurements of snow and soil moisture
in the Sierra Nevada to aid in both
process understanding and hydrologic prediction. Basin-scale variability
is captured by deploying instrument clusters
across elevation bands and major physiographic features. Local-scale variability
in aspect, forest canopy and slope is
captured by deploying sensors across the 1-2 km footprint of an instrument
cluster. This approach takes advantage of
both the multi-decadal records at index sites, and the snow density measurements
at those sites. The approach also
places these records in the context of a spatially representative measurement
network. Validation of snow products
involves back calculation of SWE values after the SCA is depleted, based
on energy balance. Spatial products show
some reproducible patterns across the central and southern Sierra Nevada,
with inter-annual differences sufficiently
distinct so to preclude use of average distribution patterns. Within an
instrument cluster, snow and soil moisture
measurements are deployed to capture both north- and south-facing aspects,
as well as differences in canopy cover
across the instrument cluster. Consistent with satellite data, ground-based
results show that snow on south-facing
slopes melted before than on north-facing slopes, resulting in drier,
warmer soils after spring snowmelt. Also, soils in
the open dried faster than those at the canopy drip edge, also reflecting
earlier snowmelt. These detailed, blended
data illustrate both the progress and interannual variability pf the spring-summer
seasonal transitions across elevation
bands in the Sierra Nevada.
Talk*
FIVE MILLENNIA OF POPULATION DYNAMICS IN A HIGH-ALTITUDE POPULATION OF
BRISTLECONE PINE
BARBER, ADELIA
University of California Santa Cruz, Department of Ecology and Evolutionary
Biology, Santa Cruz, CA
Very few study systems offer the ability to examine the detailed population
and community-level dynamics of longlived
species on time-scales relevant to their life history, or to probe the
climatic controls on population behavior over
more than a few decades. The bristlecone pines (Pinus longaeva)
of the White Mountain Range are not only the
longest-living (non-clonal) species on record, but deceased individuals
and relict wood can remain intact for millennia
in their cold and dry high elevation environment. To better understand
the forces promoting longevity and limited
recruitment of long-lived trees, I used dendrochronological analyses to
reconstruct the spatial and temporal history of
a high-altitude Bristlecone population with a relict wood record spanning
7000 years. I found substantial variability in
population growth rate, age distribution, and demographic rates of trees
over this period of time. I also found
considerable variation in mortality rates, some of which is correlated
with climatic conditions. Trends in recent
recruitment and investigation of old photographs show remarkably low juvenile
mortality and a large increase in 20th
century recruitment into juvenile classes for both bristlecone and limber
pine (Pinus flexilis). Additionally, recent
experiments and surveys have shown that recruitment of seedlings is episodic
on a decadal scale. These disparate
data sets will be used to construct stochastic demographic models, which
can be used to predict the response of
bristlecone pines to a changing climate. Understanding the population-level
consequences of extreme longevity and
the actual response of population vital rates to stochastic events can
provide an important test of the applicability of
normal demographic methods to long-lived species.
BEEVER, ERIK A. (1); RAY, CHRIS (2); MOTE, PHILIP W. (3); WILKENING,
JENNIFER L. (2)
(1) 3115 Briarcliff Dr., Anchorage, AK 99508, (2) University of Colorado,
EE Biology Dept., Boulder, CO 80309, (3)
University of Washington, JISAO/CSES Climate Impacts Group, Seattle, WA
98185
When compared against historic records of American pikas (Ochotona
princeps) from the hydrographic Great Basin
during 1898-1956, surveys during 1994-1999 and 2003-2008 suggest increasingly
rapid rates of site extirpations and
upslope retraction of the species’ distribution within sites, most
recently. To address the evidence in support of
alternative hypotheses of thermal stress on pikas, we placed 188 temperature
sensors within pika habitats starting in
May 2005 and performed vegetation surveys in the vicinity of 25 sites
with historical records of pikas in the Basin.
Occupancy status of sites was determined by visiting each site 5 or more
times during 2005-2008. We correlated our
sensor data with data from the best-correlated weather stations and used
this relationship, combined with long-term
data from the same weather stations, to back-estimate temperatures within
pika habitats at hundreds of locations
each year between 1945 and 2006. To try to explain patterns of loss, we
posited three alternative mechanisms of
direct thermal stress: a) winter-cold stress; b) acute-heat stress (indexed
by number of days >28°C); and c) chronicheat
stress (indexed by average temperature during 1 June through 31 August).
Magnitude of change was defined as
change in our thermal metrics between 1945-1975 and 1976-2006, to avoid
climatic anomalies. We found that
patterns of persistence were well predicted by metrics of climate. Our
best models suggest some effects of climate
change; however, long-term metrics of climatic conditions not previously
recognized as stressful for pikas were the
best predictors of pika persistence. Results illustrate that extremely
rapid distributional shifts can be explained by
climatic influences, even for a (homeothermic) mammal, and have implications
for conservation topics such as
reintroductions and early-warning indicators.
BEISSINGER, STEVEN R.
Museum of Vertebrate Zoology and Dept. of Environmental Science, Policy
& Management, University of California,
Berkeley, CA 94720
While global warming has clearly affected the phenology of species and
contributed to range expansions, contractions
of species’ ranges are less well documented. Assessments of effects
of climate change on the distribution of
biodiversity have been limited by use of historical surveys of short time
spans with low spatial resolution, or by
confounding effects of land use change. Furthermore, range shifts are
uncertain when confounded by false absences
due to limited historic sampling and inability to control for changes
in detectability between sampling periods. We
repeated a detailed, early 20th century survey of small mammal and bird
diversity across a 3000 m elevation gradient
spanning the long-protected landscape of Yosemite National Park (YNP),
where average annual minimum temperate
has increased by ~3Cº, and further north in Lassen National Park
(LNP). Using occupancy modeling to control for
variation in detectability, we show substantial (~ 500m on average) upward
changes in elevational limits for half of 28
small mammal species monitored in YNP. Ranges of formerly low elevation
species expanded and high elevation
species contracted, leading to changed community composition at mid and
high elevations. Responses were
idiosyncratic among closely-related and ecologically-similar species.
Birds were resurveyed at 46 locations along two
elevational transects in YNP and LNP. Nearly 50% of 70 species moved upward
in elevational range, 10% moved
downward, and 40% showed no change. Our results provide the first glimpse
into range shifts of montane California
mammals and birds in response to climate warming.
BERKELHAMMER, MAX; STOTT, LOWELL D.
Department of Earth Sciences, University of Southern California, Los Angeles,
CA 90089.
We present stable oxygen isotope data for surface waters and Bristlecone
Pine (BCP) tree-ring cellulose from the
White Mountains of California. The White Mountain Bristlecone Pine chronology
has provided valuable insight to the
temperature and drought history for western North America. We use the
oxygen isotope data from these trees to
assess circulation patterns and storm track preferences through the past
millennium. The isotopic composition of
precipitation that falls on the White Mountains varies primarily in response
to changes in storm tracks that carry
moisture from either the northern or subtropical Pacific Ocean. The BCP
should incorporate the isotopic signature of
the precipitation at annual timescales with no appreciable lag because
the soils are shallow and well-flushed. We use
a mechanistic model of isotope fractionation associated with cellulose
production to estimate modern cellulose d18O
values. The model is fully parameterized with daily instrumental climate
data. The model predicts d18O values that
closely approximate the d18O values of recent BCP cellulose. On the basis
of this agreement we extend the cellulose
d18O record to generate a history of source water variability that extends
through the 15th century. Using the Hysplit
trajectory program we have evaluated how storm trajectory variability
affected the isotopic composition of source
water and BCP cellulose for the period 1980-1999. These results illustrate
the relationship between our reconstructed
source water anomalies and storm trajectory.
Talk*
HOW CAN WE BEGIN TO TEASE APART LOCAL VS.
CLIMATIC IMPACTS TO MEADOWS IN THE SIERRA NEVADA?
BERLOW, ERIC L. (1); NIETO, BRENDA C. (1); KUHN, BILL (2); MOORE, PEGGY.
E (3); VAN WAGTENDONK, JAN W. (3)
(1) UC Merced, Sierra Nevada Research Institute, Yosemite National Park,
CA 95389 (2) Division of Resource
Management and Science, Yosemite National Park, CA 95389, (3) USGS Yosemite
Field Station, Yosemite National
Park, CA 95389
While meadows only make up a small fraction of the wilderness areas
of the Sierra Nevada, they are hotspots for both
biodiversity and recreational activity. One of the biggest challenges
to managing wilderness meadows is the difficulty
in separating out direct human impacts (e.g., trampling) from the broader
impacts of changing climate, particularly
changes in precipitation. Doing so requires synthesizing data on meadow
attributes, human use, and key
environmental variables over broad spatial scales. Since water is a critical
resource for meadow ecosystems, they may
be particularly sensitive to changes in the total amount of snow they
receive, or in the spring snow-free date. We
explored the potential for newly available estimates of Sierra-wide snow
cover for every day of the year to
characterize annual snow signatures of every meadow in Yosemite National
Park for both a “dry” and “wet” year
(2004 and 2005, respectively). We integrated these snow estimates with
other available meadow-related attributes to
explore spatial and temporal patterns of meadow attributes for all of
Yosemite’s 2,970 meadows. Using the Yosemite
Toad (Bufo canorus) as an example, we illustrate the potential
for this approach to target field sampling that would
help tease apart the relative importance of local vs. climatic drivers
of meadow change.
BISHOP, JIM (1); DENNIS, ANN (2)
California/Nevada Project of the Global Observational Research Initiative
in Alpine Environments (GLORIA)
(1) Oroville, CA 95966; (2) Sacramento, CA 95814
Plant distribution with elevation is an important guide to plant response
to climate change and a quantifiable measure
of that response. The information provides a basis for anticipating which
species may be reduced/eliminated with a
warming climate, which are likely to persist, and which could replace
those that decline.
Plant frequency and cover were assessed at 25-meter elevation intervals
over overlapping profiles extending
downward from 4 GLORIA summits, from 4325 meters (near White Mountain
summit) into subalpine woodlands at 3275
meters below Patriarch Grove. Plants were surveyed on 1mX100m belt-transects
along-contour—100 points/transect
for cover estimates, with plant occurrence noted in subsegments within
each transect.
The plants fall into 3 groups:
1. Summit specialists (ex: Polemonium chartaceum) living only
on the tops of the highest peaks
2. Alpine plants (ex: Phlox condensata and Astragalus kentrophyta)
occurring predominantly within the alpine zone
but often extending into the upper sub-alpine zone
3. Broadly-distributed plants (ex: Elymus elymoides and Chrysothamnus
viscidiflorus) that extend from the alpine
zone to the valley floors
A simple assumption of life-zone upward migration with climate warming
suggests different responses for the above
groups. Summit specialists are in the greatest danger of being eliminated
by even modest climate warming, as their
very small niches disappear. The alpine species would be expected to contract
into a smaller alpine zone. Broaddistribution
plants would be expected to extend their ranges upward. This simple picture
will no doubt be
complicated by overall changes in moisture, position and duration of late-season
snow fields, and relative distribution
of liquid vs. frozen precipitation.
Plant-distribution profiles can yield specific measures of the elevational
response of plants. Future surveys along the
same elevation profiles can be compared with earlier ones to generate
a cross-correlation as a function of elevationshift.
The maximum in that cross-correlation function will indicate the elevation
change in the entire plantdistribution
for that species.
Talk*
11,000 YEARS OF GLACIER CHANGE, PALISADE GLACIER, SIERRA NEVADA
BOWERMAN, NICOLE D. (1); CLARK, DOUGLAS H. (2)
(1) North Cascades National Park, Marblemount, WA, 98267; (2) Geology
Dept., Western Washington Univ.,
Bellingham, WA 98225
North Fork Big Pine Creek hosts the Palisade Glacier, the largest in
the Sierra Nevada, and also preserves the most
complete record of glacier change available in the range. A relatively
simple but complete moraine sequence is
complemented by well-preserved sediment deposits in the lakes downstream
of it. Distinct late-Holocene (Matthes)
and latest-Pleistocene (Recess Peak) moraines lie between the modern glacier
and the lakes. The lakes, in turn, are
excellent sediment traps and have captured essentially all of the rock
flour produced by glaciers in the cirque for the
past 11,000 years, since the retreat of the Tioga glaciers (Last Glacial
Maximum). A total of eight long cores (up to 5.5
m sediment depth) and one surface-sediment short core exhibit a consistent
record of increased and decreased rock
flour flux to the lakes linked to advances and retreats of the glacier.
Age constraints on the rock flour deposition in
First and Second lakes based on 31 14C-dated macrofossils indicate glaciers
were entirely absent in the basin between
~11,000-3200 cal yr B.P. A glacier first formed ~3200 cal. yr B.P., reaching
a maximum at 2800 cal yr B.P., followed
by four progressively larger glacier maxima at ~2200, ~1600, ~700 and
~170-250 cal. yr. B.P., the most recent peak
being the largest.
Reconstruction of the equilibrium-line altitudes (ELAs) associated with
each major advance recorded in the moraines
(Recess Peak, Matthes, and modern) indicates ELA depressions (relative
to modern) of ~250 m and 90 m for Recess
Peak and Matthes, respectively. These values represent decreases in summer
temperatures of 1.7-2.8°C (Recess Peak)
and 0.2-2°C (Matthes), and increases in winter precipitation of 22-34
cm snow-water equivalent (s.w.e.) (Recess Peak)
and 3-26 cm s.w.e. (Matthes) compared to modern conditions. Although small
compared to Pleistocene fluctuations,
these changes are significant and similar to those noted in the Cascade
Range to the north, and represent significant
departures from historical climate trends in the region.
Talk*
INTERACTIONS BETWEEN FIRE AND PLANT INVASIONS
UNDER A WARMING CLIMATE IN THE SIERRA NEVADA BIOREGION
BROOKS, MATT (1); KLINGER, ROB (2); VAN WAGTENDONK, JAN (1)
(1) USGS-BRD, Yosemite Field Station-El Portal Office, El Portal, California
95318; (2) USGS-BRD, Yosemite Field
Station-Bishop Office
Climate is one of the principal factors influencing vegetation type,
fire regimes, and plant invasions. At any single
point in time native and non-native vegetation (as fuels) affects ignition
rates and the behavior of fire, while fire
behavior is a primary force in post-burn succession patterns. This feedback
between fuels and fire behavior can have
a major effect on the characteristics of subsequent vegetation stands,
including physiognomy, species diversity,
dominance of native vs. non-native species, and net fuelbed characteristics.
Predicted future changes in precipitation
and temperature regimes in the Sierra Nevada bioregion suggest a general
elevational shift upward by vegetation
zones. However, other factors such as soil characteristics and topography
also influence vegetation and fire regimes,
and may create variable changes that do not strictly adhere to the hypothesis
of upslope shifts. Changing landscape
invasibility and effects of plant invasions on vegetation and fire regimes
may contribute additional complexity to
these changes. The potential future scenario that emerges from these interacting
factors is a shifting mosaic of
vegetation zones, rather than a directional upward elevational shift.
In this presentation we will describe some of the
potential future changes that might occur relative to vegetation and fire
regimes, including the role of plant
invasions, in the Sierra Nevada ecoregion.
BROSTOFF, WILLIAM N. (1); JEFFREY HOLMQUIST (2); JUTTA SCHMIDT-GENGENBACH
(2)
(1) U. S. Army Corps of Engineers, San Francisco District, (2) UC White
Mountain Research Station
Cryptobiotic crusts are a dominant component of a unique system of dunes
and intermittently inundated pans and
playas situated on the bed of Pleistocene Lake Thompson, Edwards Air Force
Base, California. We collected data on
the distribution and abundance of crusts, investigated responses to moisture,
temperature, light intensity, and CO2,
and conducted a microcosm experiment on the effects of branchiopods (fairy,
tadpole, and clam shrimp) on the
aquatic phase of the crusts. The crusts, which were dominated by blue-green
alga (cyanobacteria), primarily
Microcoleus, covered about 64% of the dune and 28% of the pans
and playa surfaces. Although the biomass of the
crusts was higher than generally reported for other geographic regions,
the species diversity was lower. Maximal
photosynthetic rates, measured in the field as CO2 assimilation, were
3.99 and 3.57 µmol m-2s-1 for crusts in pans and
on dunes respectively, which is somewhat lower than our laboratory measurements.
The three crust types on dunes;
pedicillated, flat, and unconsolidated (a type not previously studied),
had similar chlorophyll contents and
photosynthetic rates. Optimal moisture content was 110% and 20% for crusts
on dunes and pans respectively; lower or
higher moisture content resulted in decreased productivity. The relation
between atmospheric CO2 and net
photosynthesis was linear through at least 1000 ppm CO2 suggesting that
crusts be given increased consideration in the
context of global climate change. The presence of shrimp in a laboratory
microcosm had no effect on algal species
composition or abundance.
Talk*
ANCIENT BRISTLECONE PINE DISTRIBUTION AND GROWTH IN THE WHITE MOUNTAINS
OF CALIFORNIA: A SPATIAL ANALYSIS
BUNN, ANDREW G. (1); SALZER, MATTHEW W. (2); HUGHES, MALCOLM K. (2);
LEWIS, JUSTIN N. (1); KIPFMUELLER, KURT F. (3)
(1) Department of Environmental Sciences, Western Washington University,
Bellingham, WA 98225; (2) Laboratory of
Tree-Ring Research, University of Arizona, Tucson, AZ 85721; (3) Department
of Geography, University of Minnesota,
Minneapolis, MN 55455
We present results from a series of ongoing studies of high-elevation
bristlecone pine in the White Mountains of
California. First we show that the spatial distribution of Great Basin
bristlecone pine (Pinus longaeva) near the upper
forest border is associated with radiation load while soil moisture and
slope play more minor roles. Second, we show
that the upper elevation limit of bristlecone pine showed ring growth
in the second half of the 20th century that was
greater than any in the last three and a half millennia and well correlated
to temperature. In a multivariate analysis
we show bristlecone growth varied strongly along an elevational transect
and less strongly according to biophysical
location and morphology. Understanding the factors controlling bristlecone
pine growth remains a substantial
challenge to ‘unmixing’ past temperature and precipitation
variability.
Talk*
PRELIMINARY WATER CHEMISTRY INVESTIGATIONS,
UPPER SAN JOAQUIN AND DRY CREEK WATERSHEDS
BURAK, SUSAN (1); FARRAR, CHRISTOPHER (2)
(1) Hydrologic Sciences Program, University of Nevada, Reno, and (2) U.S.
Geological Survey, Carnelian Bay CA 96140
The Town of Mammoth Lakes has experienced rapid growth in the last 10
years as a result of real estate speculation,
community growth and expansion and improvements at Mammoth Mountain. As
a result, the Town has outgrown its
allocated surface water diversions from Mammoth Creek. Currently, eight
production wells supply almost half of the
water needed by the Town under normal precipitation conditions and about
70% during multiple dry year conditions.
In the future, increases in groundwater pumping will be needed to meet
the water demand of the Town at full build
out. The Mammoth Community Water District along with Mammoth Mountain
Ski Area (MMSA) is considering expanding
its water gathering activities north to the Dry Creek Basin. The headwaters
of the Owens River begin at the eastern
part of the watershed, about 20 km northeast of Mammoth Mountain.
Previous work conducted by the USGS in the 1980’s and 1990’s
evaluated water chemistry and inorganic carbon levels
in cold springs and surface water in the Dry Creek Basin and Red’s
Meadow valley. The large developments planned for
Upper Dry Creek, increased use of groundwater by the Ski Area for snowmaking,
and a proposal to transport
groundwater from Dry Creek to the Mammoth Basin, provide the motivation
for undertaking a study to increase the
understanding of the effects of ground-water pumping on both the Dry Creek
Basin and the spring complexes and
creeks on the San Joaquin Ridge.
A field sampling campaign began in June 2008. Water samples were collected
from springs on Mammoth Mountain,
Upper Dry Creek, the San Joaquin Ridge and Big Springs and analyzed for
major ion, isotopes of water and dissolved
inorganic carbon. Preliminary results show unusual differences in water
chemistry at two springs in the Big Springs
complex and an anomalous enriched spring on San Joaquin Ridge. The studies
are on going; here we present data in
Piper diagrams and isotope data plots with preliminary interpretations.
BUTZ, RAMONA (1); DENNIS, ANN (2), MILLAR, CONSTANCE (3); WESTFALL,
ROBERT (3)
(1) University of California Merced, Merced, CA 95344, (2) Calflora, Berkeley,
CA 94709, (3) USDA Forest Service, PSW
Research Station, Albany, CA 94701
The Global Observation Research Initiative in Alpine Environments (GLORIA)
is a worldwide network of long-term
research sites established to assess the impacts of climate change in
sensitive native alpine communities. Many alpine
species face habitat fragmentation and loss, and even extinction because
they are adapted to cold temperatures and
very limited in their geographic distribution. This study summarizes the
data collected from four sites comprised of
three to four summits each in the Sierra Nevada and White Mountain ranges
of California. The 14 summits cover
elevational gradients ranging from 3170m to 4285m. On each summit, habitat
characteristics, species composition,
species cover, and frequency counts were recorded in sixteen 1m x 1m quadrats.
Additional surveys on the percentage
cover of surface types and of each species in eight larger plots extending
to 10m below the summit focus on detecting
changes in species richness and species migrations. Sites were analyzed
both independently and as a group to explore
similarities and differences in species composition, plant functional
groups, and response to climate. A total of 124
species were identified across all sites. The summits within each site
exhibited rich, heterogeneous plant
communities, but ones in which most species were infrequent. Northern
slopes generally had the highest vegetation
cover and eastern slopes, the lowest. Elevation, aspect, and substrate
all strongly influenced community composition.
The average minimum winter soil temperature varied by more than 10ºC
between the lowest and highest sites in the
gradient. Resampling over time will allow us to discern trends in species
diversity and temperature, and assess and
predict losses in biodiversity and other threats to these fragile alpine
ecosystems. Results from this work will expand
existing long-term data sets on the effects of climate change in alpine
environments; and provide standardized,
quantitative data on the altitudinal differences in species richness,
composition, vegetation cover, soil temperature,
and snow cover period.
Talk*
DISTRIBUTION OF AMBIENT OZONE AND
NITROGENOUS AIR POLLUTANTS IN SIERRA NEVADA AND OWENS VALLEY
BYTNEROWICZ, ANDRZEJ (1); BURLEY, JOEL (2); CISNEROS, RICARDO (3); WOOD,
YVONNE (4); PROCTER, TRENT (5) PREISLER, HAIGANOUSH (6); WARNER, KATY
(7); TARNAY, LELAND (7); DULEN, DEANNA (8); ESPERANZA, ANNIE (9)
(1) US Forest Service, PSW Research Station, Riverside, CA; (2) Saint
Mary’s College, Moraga, CA; (3) US Forest
Service, Region 5, Clovis, CA; (4) University of California Extension
Service, Bishop, CA; (5) US Forest Service, Region
5, Porterville, CA; (6) Yosemite National Park, El Portal, CA; (8) Devils
Postpile National Monument, Mammoth Lakes,
CA 93546; (9) Sequoia National Park, Three Rivers, CA
Monitoring of ambient ozone (O3), ammonia (NH3), nitric oxide (NO), nitrogen
dioxide (NO2), and nitric acid (HNO3)
concentrations was conducted in southern Sierra Nevada and Owens Valley
during 2007 and 2008 summer seasons.
Real time O3 concentrations were measured with UV absorption instruments
while mean 2-week long concentrations of
O3, NH3, NO, NO2 and HNO3 were measured with passive samplers. These investigations
were aimed at understanding
background concentrations of criteria pollutants (O3 and NO2) and pollutants
that significantly contribute to
atmospheric nitrogen deposition to terrestrial and aquatic ecosystems
(NH3 and HNO3). Effects of long-range transport
of pollution plumes from California Central Valley and Los Angeles Basin
and emissions from wildland fires on
concentrations and distributions of the measured pollutants were investigated.
Results of these investigations will be
used for evaluation of risks caused by these pollutants to people, forests
and other ecosystems. These results will also
help federal and state air resources and land managers to understand potential
effects of prescribed burning on air
quality in Sierra Nevada and the surrounding areas.
Plenary Talk*
HOW WILL CLIMATE CHANGE AFFECT WATER RESOURCES
IN THE EASTERN SIERRA?
CAYAN, DANIEL
Scripps Institution of Oceanography, University of California San Diego,
and US Geological Survey, La Jolla, CA
Recent climate model simulations provide an alarming set of scenarios
of possible changes that could unfold in Eastern
Sierra climate and hydrology. It is very likely that global warming has
already been affecting the California region,
and with the increasing accumulation of greenhouse gases, the climate
models indicate that much larger changes
could set in. Temperatures in the Sierra would not merely become warmer,
they would probably progressively warm
through the 21st Century. An important part of the water supply to the
Sierra that historically has come in the form of
snow would probably shift to rain, and some of the snow which does fall
would melt earlier than in the present day.
Along the steep elevations of the Eastern Sierra, these changes would
be dispensed in very short distances—this would
result in very compressed set of changes in ecosystems of the region.
Among the mountain ranges across the western
United States, the annual delivery of precipitation in this region is
remarkably volatile, being prone to multi-year
droughts and occasional wet spells and large storms. Climate change may
exacerbate this, and the eastern Sierra
might be, during some spells, effectively drier than present while occasionally
being affected by greater floods.
Talk
TOWARDS A FIELD-BASED UNDERSTANDING OF
CLIMATE CHANGE-INDUCED SHIFTS IN TREE SPECIES RANGES
CHUANG, TERESA J. (1); HARTE, JOHN (1, 2)
(1) UC Berkeley, Department of Environmental Science, Policy, and Management,
Berkeley, CA 94720, (2) UC
Berkeley, Energy and Resources Group, Berkeley, CA 94720
We have been studying seed dispersal and seedling dynamics in an eastern
Sierra Nevada forest in order to make more
accurate predictions of climate change-induced shifts in tree species
ranges. Anticipated decreases in summer soil
moisture in this system are predicted to result in an uphill shift in
tree species ranges, potentially leading to further
feedbacks to climatic change. However, the mechanistic basis for such
a shift has yet to be determined. We have
therefore combined observational and manipulative approaches in our study
of Pinus jeffreyi to 1) determine whether
patterns of seed rain are correlated with patterns of seedling germination
and establishment; 2) establish whether
current geographic ranges are limited by existing climatic conditions;
and 3) evaluate the effects of a climate
manipulation that simulates predicted advancements in snowmelt date on
seedling germination and establishment
success within and above the current range. Significant overlap in the
recruitment niches of P. jeffreyi and the uphill
species it is predicted to replace, along with limited dispersal, suggest
that contrary to the predictions of current
bioclimate models, rapid uphill shifts in tree species ranges in this
system are unlikely to occur.
Plenary Talk*
CLIMATE AND GLACIERS OF THE SIERRA
NEVADA: THE VIEW FROM THE ICE
CLARK, DOUGLAS H. (1); BOWERMAN, NICOLE D. (2)
(1) Geology Dept., Western Washington Univ., Bellingham, WA 98225; (2)
North Cascades National Park,
Marblemount, WA, 98267
The modern Sierra Nevada plays host to a dwindling number of small alpine
glaciers. Despite their diminutive size,
these glaciers provide important local environments, late-summer streamflow,
and crucial constraints on past
climate change. Detailed analysis of moraines and lake sediments below
these glaciers constrains both the timing
and magnitude of the climate changes that have affected both the High
Sierra and the intermountain west over the
past 11,000 years. Whereas moraines offer “snapshots” of maximum
glacier positions, proglacial lakes provide more
complete records of glacier ebb and flow. The lakes act as efficient sediment
traps for rock flour emanating from
the glaciers, preserving continuous, datable, high-resolution proxy records
of extent and timing of glacier growth
and decay. The moraines in turn provide a means to quantify the climate
changes driving these fluctuations.
The Sierra Nevada, along with most of the mountains of the America Cordillera,
appears to have been largely
glacier-free for most of the last 11,000 years (the Holocene period).
Beginning about 3200 cal yr B.P., cirque
glaciers began to reform in the Sierra Nevada and the Cascades, culminating
with maximum advances late in the
Little Ice Age (LIA). The largest glacier in the Sierra Nevada, the Palisade
Glacier, attained progressively greater
maxima after 3200 cal yr B.P., with peaks at ~2800, ~2200, ~1600, ~700
and 170-250 cal yr B.P. Since the last
(Little Ice Age) maximum, the lakes below the Palisade Glacier record
a substantial decline in rock flour deposition
related to the thinning and shrinking of the glacier in Historic times.
Studies from other ranges in the western US
show a remarkably similar pattern: onset and significant growth of glaciers
starting about 3200 yr ago, multiple
episodes of growth and decay of ice, culminating with the Little Ice Age
maximum ~150-200 yr ago.
Historic photos record the continued shrinkage (and in some cases the
disappearance) of glaciers in the Sierra
Nevada and elsewhere. Recent reports of anomalous growth of the glaciers
at Mt. Shasta are likely the result of
locally enhanced winter snowfall there that has outpaced warming during
the past 60 years. In contrast, the
continued shrinking of the glaciers of the Sierra Nevada (and in fact
the rest of North America) emphasizes the
broader trend of warming outpacing any local precipitation increases.
The combined records of moraines and alpine lake sediments provide clear
constraints on historic and prehistoric climate change in the American
Cordillera. For much of the Holocene, conditions were too warm and dry
to support significant permanent ice; a dramatic change occurred ~3200
yr ago that initiated glacier growth simultaneously throughout much of
the region. The maximum extent of glaciers in the West immediately preceded
major population expansion in the region; their steady shrinkage in the
last 150 years records arguably one of the most
dramatic environmental changes of the last 10,000 years, and indicates
that the Sierra Nevada and other mountains
of the west may soon return to the glacier-free conditions characteristic
of the early and mid-Holocene.
CLARK, JORDAN F. (1); RADEMACHER, LAURA K. (2); BLUMHAGEN ERIK D. (3)
(1) Department of Earth Science, University of California, Santa Barbara,
CA 93106, (2) Department of Earth &
Environmental Sciences, University of the Pacific, Stockton, CA 9521,
(3) Shannon & Wilson, Inc. 400 N 34th Street,
Seattle, WA 98103
Springs are natural windows into groundwater systems, which are good
archives of signals inherited at the time of
recharge as well as those gained during the subsequent groundwater flow.
These processes include water rock
interactions and temporal variations of external forcing often related
to climatic and anthropogenic changes. Stable
isotope compositions of shallow groundwater emerging from springs in the
high elevation, central Sierra, Sagehen
basin decrease with increasing geochemical groundwater apparent ages.
From waters recharging in 1960 to waters
recharging in 1990, there is a 1.2‰ and 11‰ increase in 18O
and D, respectively. Historic temperature records from
surrounding areas show about a 2°C mean winter temperature increase
over the same period. This temperature
change alone is not great enough to explain the observed increase in 18O.
We suggest that changes in atmospheric
circulation patterns or changes in snow melt processes account for the
remaining offset in 18O. Spring radiocarbon
(14C) content ranged between 85 and 110 pmc and vary with apparent age,
whereby the youngest groundwater has the
highest radiocarbon values. The spring radiocarbon is set by the soil
pCO2 because the aquifer contains little
carbonate and its trend can be best described assuming the soil CO2 is
composed of a 50:50 mix of young (15-25 years)
and old (4000 years) soil carbon reservoir sources for the early part
of the record and a 33:67 mix for the later
portion. These results are consistent with previous soil carbon studies
and demonstrate that soil carbon dynamics are
variable within the watershed. The timescale of these geochemical changes
recorded in the hydrologic records is
short (decadal scale) and suggests that the geochemistry of groundwater
is an extremely useful tool for studying
climate and other watershed changes over these intervals.
Poster
CLIMATIC AND EDAPHIC DRIVERS OF ECOSYSTEM INVASIBILITY BY BROMUS TECTORUM
L. IN THE EASTERN SIERRA NEVADA
CONCILIO, AMY; LOIK, MICHAEL
Department of Environmental Studies, University of California, Santa Cruz,
CA 95064
Bromus tectorum L., has displaced native shrub and bunchgrass communities
in large portions of the Great Basin
Desert. At higher elevations at the ecotone with the eastern Sierra Nevada
conifer forests, B. tectorum invasion has
been slow. However, changing climatic patterns and edaphic conditions
may facilitate increased establishment and
growth of B. tectorum. This research tested hypotheses regarding changes
in snowpack and increases in nitrogen (N)
deposition, and their effects on ecosystem invasibility by B. tectorum.
Snow depth was manipulated with snow
fences, and paired plots were established within each snow treatment to
simulate increased and ambient levels of N
deposition. Plots were established in three microhabitats common at 2150
m: under Artemisia tridentata and Purshia
tridentata canopies, and in open, intershrub spaces. Bromus tectorum growth
and fecundity were measured
throughout the 2008 growing season, as was native species composition
and abundance. During the first year of
treatment application, there were no apparent changes in species diversity
or composition. However, the number of
B. tectorum spikelets per individual increased with increased N and with
both increased and decreased snowpack
compared to ambient conditions. N additions resulted in greater B. tectorum
biomass under Artemisia tridentata
canopies compared with control conditions, but had no effect under the
nitrogen-fixer Purshia tridentata, suggesting
N saturation under P. tridentata microhabitats. Overall, results suggest
that B. tectorum may have increased fitness
under future climatic and edaphic patterns, thereby portending greater
impact at this elevation. Monitoring and
control efforts for B. tectorum in a future climate should focus on transportation
corridors and invasion-risk areas at
elevations above current occurrence.
DAHLHOFF, ELIZABETH (2,3); RANK, NATHAN (1,3)
(1) Sonoma State University, Rohnert Park, CA 95472; (2) Santa Clara University,
Santa Clara CA; (3) White Mountain
Research Station, Bishop CA 93514
Understanding how climate change affects natural systems requires investigations
of effects of environmental
variation on the physiology and performance of vulnerable species. The
willow beetle Chrysomela aeneicollis lives in
isolated, high elevation mountain drainages at the southern edge of its
global range, where it is regularly exposed to
temperatures that cause physiological stress and reduce performance, survival
and reproductive success. In these
populations, the glycolytic enzyme locus phosphoglucose isomerase (PGI)
shows much greater differentiation than
other polymorphic enzyme loci, with the PGI 1 allele being most common
in cool localities further north, and PGI 4 in
warmer, southern localities. Variation at the PGI locus relates to traits
that allow individuals to cope with a changing
thermal environment. Allozymes of the PGI dimer differ in thermal stability
and catalytic efficiency (1-1 < 1-4 < 4-4).
Expression of stress inducible heat shock proteins (Hsps) is typically
higher and induced at lower temperature for
individuals possessing PGI 1 than those possessing PGI 4, and thermal
tolerance is greater for individuals that show
elevated Hsp70 expression levels. PGI genotypes also differ with respect
to performance and reproductive characters.
At moderate temperatures or after a single exposure to stress, PGI 1-1
genotypes are more thermotolerant, run faster,
have higher larval growth rates, greater male mating success and female
fecundity than 4-4 individuals, while 1-4
heterozygotes show intermediate values. However, repeated exposure to
thermal extremes reverses this pattern (4-4
> 1-4 > 1-1) for most characters. We propose that 4-4 individuals
may recover more readily from repeated stress
exposure than individuals possessing the 1 allele via more tightly regulated
expression of Hsps. These results suggest
that functionally important genetic variation affects the heat shock response,
which may be one mechanism by which
genetically diverse populations to respond effectively to environmental
change.
Talk*
MAMMOTH MOUNTAIN SKI AREA’S RESPONSE
TO GLOBAL WARMING
DALLAS, GREGORY
Mammoth Mountain Ski Area, Mammoth Lakes, CA 93546
Climate change has impacted and is impacting the Ski Industry. Nowhere
is this more apparent than in Europe at busy
ski centers such as Zermatt and Verbier Switzerland. Less than a decade
ago, skiers could be transported to the
highest peaks via gondola, chairlift, or tram and over the course of the
day ski back down to the valley floor. This is
no longer possible at many ski areas in Europe as the snowline has receded
and the same gondola that moved skiers
upward is now being used to transport skiers back down to the valley floor.
Although the snowlines haven’t
consistently receded to the same extent in the U.S., shorter, warmer,
and dryer winters are threatening the
prosperity of many ski areas causing the U.S. industry to look at new
technologies and business opportunities.
The lift infrastructure once used exclusively for downhill skiing is now
being used to transport guests for a variety of
winter activities in addition to skiing such as snowboarding, sledding/tubing,
alpine sliding and to transport guests for
a variety of summer activities such as mountain biking, zip lines, and
hiking. As the climate changes, the desire of our
guests to enjoy the pristine outdoor environment doesn’t. The ski
industry will need to adapt its business models and
infrastructure to take advantage of the evolving tastes and preferences
of our guests. Climate change is just one of
many threats to the sport of downhill sliding as financial pressure (the
rising cost of operations and therefore the
higher price of ski vacations) continues to be the greatest threat to
ski areas. The companies and communities that
prosper will be those that use innovation as their competitive advantage.
In the future, it won’t be good enough to be
a “great” operator providing great grooming, services, or
food. Only those who adapt to climate change, financial
pressures, and other business drivers by creating innovative new products
and services for the changing needs of their
guests will be sustainable.
Talk*
FIELD-MAPPED WETLANDS AT DEVILS POSTPILE
NATIONAL MONUMENT
DENN, MARIE; DONNA SHORROCK
USDI National Park Service, Water Resources Division, Pt. Reyes, CA
Wetlands are keystone ecosystems that provide a unique suite of ecological
services, including mitigation of flood
pulses, aquifer recharge, water quality improvement, and habitat for flora
and fauna. Despite this, wetlands are
threatened across the West. Nineteenth and twentieth-century wetland degradation
has made intact wetlands on
public lands even more important to maintaining landscape-scale ecological
integrity. In 2006, staff from the National
Park Service Water Resources Division visited Devils Postpile National
Monument to field-map and classify park
wetlands according to the Cowardin wetland classification system, in order
to better understand the abundance,
distribution condition and value of Monument wetlands. Project staff mapped
forty-three wetlands in six Cowardin
classes covering nearly sixty acres, or about 8% of the total Monument
lands. Project staff assessed the condition of
mapped wetlands with the California Rapid Assessment Method for Wetlands
and Riparian Areas (CRAM). In the field
project staff evaluated four attributes – buffer condition, hydrology,
biotic structure, and physical structure – of each
park wetland by answering a series of questions based on single-visit
observations of the habitat. Answers to these questions created a score
for each wetland, indicating its condition or ecological value.
NPS staff created a description of desired condition for monument wetlands,
and considered each mapped wetland’s
CRAM score, degree of anthropogenic stress, and other observation to categorize
the unit as in desired condition, good
condition, or poor condition, relative to the standard. The project concluded
that, overall, 37% of DEPO’s wetland
acres achieve desired condition, 63% are in good condition, and less than
0.5% are in poor condition. Field staff also
noted anthropogenic disturbances in wetlands which may adversely affect
wetland health and function. Evidence of
fire, passive recreation, and active recreation are the three most commonly
observed wetland stressors at the
Monument.
DENNIS, ANN
CalFlora, Sacramento, CA
The Global Observation Research Initiative in Alpine Environments (GLORIA)
is an international research project based
in Vienna, Austria, with the goal to assess climate change impacts on
vegetation in alpine environments worldwide.
Standardized protocols direct selection of each node in the network, called
Target Regions. Each Target Region
consists of a set of four geographically proximal and bioclimatically
similar mountain summits at elevations that
extend from treeline elevation to the nival zone, or whatever biome is
the highest for the local area. For each
summit, GLORIA specifies a rigorous mapping and sampling design for data
collection, with re-measurement intervals
of five years; the design standards were developed to enable statistically
meaningful comparisons among Target
Regions around the world. Whereas Target Regions have been installed in
six continents, prior to 2004 none was
completed in North America. In cooperation with the Consortium for Integrated
Climate Research in Western
Mountains, by 2008 five Target Regions were completed in the Sierra Nevada/Great
Basin region, one in the Sierra
Nevada on Mt Dunderberg, two in the White Mountains (one on dolomitic
soils, one on other substrates; White
Mountain Plateau area), one in the Lake Tahoe Basin (Freel Pk), and one
in Great Basin National Park, NV. During the
course of establishing these Target Regions, an important modification
was made to improve estimations of plant
cover. Comparative data analysis of the baseline measurements is underway
and floristic results will be presented in
other talks for this session.
DEROSE, MARGIE B.; KENNEDY, MARTIN J.
Department of Earth Sciences, University of California, Riverside 92521
Eastern Sierra Nevada climatic research aims to test the hypothesis
that mountain glacial advances correlate with the
marine isotope record and other short term events. Winter storm frequency
likely governs glacial advance, which may
signify a possible connection with the northern hemisphere climate system.
For example, a southerly shift of the jet
stream may suggest high pressure to the north due to the presence of a
large continental ice sheet. While the Sierran
climate record is well-preserved in lake sediments and moraines, correlation
to the marine or ice core d18O record
remains problematic beyond 30 ka due to poor absolute age control. Lake
sediments provide a high resolution record
of open and closed conditions, but can only be inferred to document glacial
advances, whereas moraines provide the
only direct record of glaciation. Only two absolute age constraints exist
for the timing of moraine advances in the
eastern Sierra. The Sherwin till is overlain by the Bishop Tuff, providing
a minimum age of 759 ± 2 ka (Sarna-Wojcicki
et al., 2000), and the Casa Diablo till is reported to be constrained
by underlying and overlying basalt flows with
assigned dates of 126 ± 25 ka and 62 ± 13 ka (Bailey et
al., 1976). All other glacial advances interpreted from
moraines are inferred from these two ages (outside cosmogenic dates).
Detailed mapping of the Casa Diablo till,
however, does not support initial reports (Bailey et al., 1976) of an
upper bounding basalt flow, instead only suggests
that the Casa Diablo till is younger than ~126 ka and, therefore, cannot
be distinguished from other moraines
considered to be of Tahoe or Tioga age in the Mammoth Lakes region. The
lack of a younger age constraint leaves a
disconcerting void in the glacial record, especially during the interval
corresponding with marine isotope stage 6,
which should be recorded in the Sierran record. Instead, a series of only
relatively dated moraines occur, with little
criteria for direct correlation to broader climate controls and stresses
the need for further absolute age control before
they can be used to test hemispheric teleconnections.
Talk*
TIME-SPACE CONTINUITY OF FRACTIONAL SNOW
COVER IN THE SIERRA NEVADA FROM MODIS
DOZIER, JEFF
Donald Bren School of Environmental Science and Management, University
of California, Santa Barbara, CA
Using reflectance values from the 7 “land” bands of NASA’s
Moderate-Resolution Imaging Spectroradiometer (MODIS)
with 250 or 500m resolution, we estimate the fraction of each 500m pixel
that snow covers, along with the albedo of
that snow. The daily products have data gaps and errors because of cloud
cover and sensor viewing geometry, so we
interpolate and smooth to produce our best estimate of the daily snow
cover and its albedo. We consider two modes:
one is the “predictive” mode, whereby we estimate the snow-covered
area and albedo on that day using only the data
up to that day; the other is the “retrospective” mode, whereby
we reconstruct the history of the snow properties for
a previous period, typically a month or a season. The product is available
to any interested user for the Sierra Nevada
from 2000 to present. We are interested in working with users to pick
the best mechanisms and formats for
distribution. Moreover, the best test of a dataset is its utility for
scientific research, and we want users’ feedback
Talk*
CHALLENGES AND OPPORTUNITIES FOR MANAGING
DEVILS POSTPILE NATIONAL MONUMENT DURING CLIMATE CHANGE
DULEN, DEANNA
Devils Postpile National Monument, Mammoth Lakes, CA 93546
This panel will explore the challenges and opportunities for managing
Devils Postpile National Monument (DEPO) in
this era of climate change within the setting of the Upper Middle Fork
of the San Joaquin. The biological diversity and
ecological significance will be presented, along with the geological context
that creates the unique setting of the
Upper Middle Fork of the San Joaquin. The concept of managing this area
as refugium will be explored in the context
of the he working definition as: Physical environments that are less affected
by climate change than other areas (e.g.,
due to local currents, geographic location, etc.) and are thus a “refuge”
from climate change for organisms.
Presentations will include: Information on climate variability and impact
3), including information on projected
climate and hydrologic changes (3) physical and ecologic vulnerabilities
of wetlands (4), and surface and groundwater
hydrology (5). Some challenges and opportunities for management in addressing
climate change will be explored,
including watershed values, operational and strategic monitoring, adaptation,
and mitigation need (1,2).
Talk*
ALPINE SHRUB-CHRONOLOGY, A TOOL FOR HIGH-ELEVATION
ECOLOGICAL MONITORING
FRANKLIN, REBECCA S.
Laboratory of Tree-Ring Research, Tucson AZ 85721
Herbchronology, a technique adapted from dendrochronology, is the study
of the annual growth rings in roots of
certain perennial dicotyledonous plants. The presence of annual growth
increments in plants in alpine and abovetreeline
environments is significant as it highlights the importance of herbchronology
for climatic, ecological and
geomorphologic applications in alpine and above-treeline ecology. Results
from a study of the plants colonizing
Barney Rock Glacier at 3200 meters elevation adjacent to Mammoth Pass,
Mono County, CA, show these plants have an
inverse relation to snowpack than trees but a positive response to summer
temperature. Similar woody shrubs
colonize GLORIA (Global Observation Research Initiative in Alpine Environments)
monitoring sites in the Sierra Nevada.
I have sampled these species (Leptodactylon pungens, Phlox diffusa,
Ribes cereum and Ericameria spp.) on peaks
immediately adjacent to the GLORIA sites at Dunderberg Peak and Granite
Lakes (initially GLORIA alternate sites).
Above-treeline shrub-chronologies (50 – 100 years in length) such
as these can shed light on how sensitive alpine
ecosystems will respond to changing climate. Here I present the resulting
chronologies and discuss how the climate
and ecological information gained from this method of study can compliment
and add to the monitoring work done at
high elevation sites.
Talk
THE EFFECT OF MAMMALIAN AND AVIAN SEED
DISPERSERS ON LONG-LIVED BRISTLECONE PINES
GARCIA, JEFFREY
University of California Santa Cruz, Department of Ecology and Evolutionary
Biology, Santa Cruz, CA
Relationships between Pinus species and seed caching animals
are common in the Eastern Sierra and Great Basin
regions of California and Nevada. For some pine species, the germinated
seed from unrecovered caches makes up a
significant portion of population wide recruitment. However, the extent
to which seed-caching birds and mammals
contribute to the dispersal of long-lived bristlecone pine seeds (Pinus
longeava) is unknown. Some pines, such as
limber (P. flexilus) and whitebark pine (P.albicaulis),
are completely dependant on caching animals to disperse their
large, wingless seeds. Bristlecone pine seeds are smaller (~ 5.5 mg),
and have retained the ability to disperse by
wind, yet many known caching animals will forage on their seeds. Reports
of occasional bristlecone seed dispersal by
animals such as Clark’s Nutcrackers (Nucifraga columbiana)
have persisted in the literature for many years, yet no
comprehensive study has been performed to explore the true extent of either
avian or mammal dispersal. To identify
potential seed caching species, I used tracking boards baited with bristlecone
seeds, direct observation of known
caching species, and camera traps. To quantify dispersal distance and
percentage of recovered caches, I tracked
cached seeds that were powdered with a fluorescent dye, which was easily
seen using ultraviolet flashlights. I have
gathered data describing the nature of these caches (seeds per cache,
distance from seed source, and cache depth)
around four bristlecone groves and adjoining habitat types. Future research
will determine whether unrecovered
caches yield first year seedlings. This research illustrates that occasional
caching of bristlecone seeds by birds or
mammals may have enormous population-wide implications for the ancient
bristlecone groves of the White Mountains.
Talk*
CLIMATE MONITORING AT DEVILS POSTPILE
GEHRKE, FRANK
California Department of Water Resources, California Cooperative Snow
Surveys, Sacramento, CA
Devils Postpile National Monument represents a unique opportunity to
monitor and evaluate changes in climate and
the effects on the environment. The California Department of Water Resources,
has embarked on three coupled
projects, representing different time and spatial scales to foster development
of an enhanced monitoring network and
forecasting environment, currently on a pilot scale in the American River
Watershed, that will be expanded to other
Sierran watersheds. The first project SNAMP,-Sierra Nevada Adaptive Management
Project is a small watershed scale examination of the effect of a specific
fire management tool and provides the infrastructure to examine climate
changes occurring at
mid elevation locations. The second project, HMT- Hydrometerologic Testbed
encompasses the North Fork of the American River Watershed and incorporates
a significant atmospheric component, coupled with ground observations
to produce short duration
runoff forecasts specifically to improve reservoir management response
to flood events. The third component is an advancement in seasonal water
supply forecasting entitled H20 2. This project entails the melding of
ground based observations of snow depth, water content and density with
MODIS satellite observations of snow covered area to produce total snow
water content volume draped over the terrain. Armed with additional soil
moisture and solar radiation measurements a distributed parameter hydro
logic simulation model will be developed that would provide not only enhanced
seasonal forecasts but the ability to accurately portray effects on runoff
resulting from climate change.
GRULKE, NANCY (1); SEYBOLD, STEVE (2); GRAVES, ANDY (2); DEMMIG-ADAMS,
BARBARA (3); ADAMS, WILLIAM (3)
(1) USDA Forest Service, PSW Research Station, Riverside, CA, (2) USDA
Forest Service, PSW Research Station, Davis,
CA, (3) Evolutionary, Population, and Organismal Biology, University of
Colorado, Boulder, CO
Yellow pine (Jeffrey and ponderosa) in California experience
chronic bark beetle outbreaks and tree mortality during
extended droughts, a characteristic of the Mediterranean-type climate.
Thinning may improve stand health during
periods of drought stress by increasing individual tree access to water,
carbon, and nutrient resources. Resource
availability, as modified by disturbance regimes, may determine tissue
palatability and resin production. Resin
presents a physical barrier to bark beetles. However, resins emit volatile
organic compounds, which emit volatile
organic compounds that are attractive to bark beetles. We present preliminary
results from an ongoing study of the
level of drought stress, resin production, canopy health, and current
rates of bark beetle attack experienced by
Jeffrey pine in east side stands located in the Transverse Range (San
Bernardino National Forest), Sierra Nevada
(Sequoia NF, Inyo NF, Tahoe NF), and the southern Cascade Range (Lassen
NF). In each NF, 50 to 70 trees were
selected for intensive study in either thin or dense stands. In three
of the NF, trees in prescribed burns were selected
for study as well. Data from a west side stand in Sequoia National Park
with one of the highest rates of mortality due
to bark beetle will be presented for comparison. This research will help
determine optimal stand density of an
economically important pine in the western U.S., with the intent of identifying:
1) stand management effects on
individual tree health; 2) threshold levels of tree drought stress that
lead to bark beetle epidemics, and 3) plant stress
indicators for early detection of ecosystems at risk.
Talk*
CHANGING CLIMATE AND WILDERNESS MANAGEMENT PERSPECTIVES
GUENTHER, GARY
Wilderness Watch, Mammoth Lakes, CA
Wilderness, as envisioned by its framers and embodied in the Wilderness
Act, has a singular purpose: to set aside
portions of the landscape to be administered so as to protect their Wilderness
Character. Wilderness is the one place
where natural processes are mandated to function unimpeded by human activities.
Climate change is, in part, the
result of human activity, but this is not necessarily a justification
to intervene and impede natural processes within
Wilderness. A critical component of Designated Wilderness is that it provides
lands that, for the most part, have not
had their natural functions altered by man providing a baseline for which
to compare management actions in nonwilderness
lands. One must be extremely cautious in considering management actions
that alter natural functions
within Wilderness. One situation that presents a special dilemma is that
the Wilderness Act and the Endangered
Species Act are at odds when it comes to altering natural functions on
behalf of threatened & endangered species that
predominately inhabit Wilderness.
Talk*
A NEW LAKE MONITORING PROGRAM IN SIERRA
NEVADA PARKS
HEARD, ANDREA M. (1); STARCEVICH, LEIGH ANN HARROD (2); SICKMAN, JAMES
O. (3); ROSE, MERYL GOLDIN (4); SCHWEIZER, DONALD W. (1); MUTCH, LINDA
S. (1)
(1) Sierra Nevada Network, Sequoia and Kings Canyon National Parks, 47050
Generals Highway, Three Rivers, CA,
93271; (2) Statistical Consulting, PO Box 1032, Corvallis, OR 97339-1032;
(3) University of California, Riverside,
Department of Environmental Sciences, Riverside, CA 92521; (4) Sierra
Nevada Network, Yosemite National Park,
P.O. Box 700, El Portal, California, 95318, CA 92521; (4) Sierra Nevada
Network, Yosemite National Park, P.O. Box
700, El Portal, California, 95318
The Sierra Nevada Network (SIEN) Inventory & Monitoring Program
recently completed and field-implemented its longterm
lake monitoring protocol for Sequoia, Kings Canyon, and Yosemite National
Parks. The lake protocol captures
three of the SIEN’s high priority vital signs: water chemistry (primary
vital sign that drove protocol design), surface
water dynamics, and amphibians. Lake ecosystems were selected for monitoring
because they are valued for their
ecological importance, recreational opportunities, and importance to regional
water supplies, are threatened by
multiple stressors, and are sensitive to change. SIEN lakes are habitat
for three amphibian species that are candidates
for listing as endangered under the federal Endangered Species Act––mountain
yellow-legged frog (Rana muscosa and
Rana sierrae) and Yosemite toad (Bufo canorus). We use a probabilistic
sample design that addresses access
challenges in remote areas and balances temporal and spatial sampling
objectives. The protocol was developed
collaboratively by SIEN, Yosemite, and Sequoia and Kings Canyon Park staff
and cooperators from multiple universities
and state and federal agencies.
HERBST, DAVID B.
Sierra Nevada Aquatic Research Laboratory, University of California, Mammoth
Lakes, CA 93546
The changing hydrology of mountains streams in western North America
over the past 50 years shows widespread and
similar patterns consistent with climate warming trends. The most notable
changes in how hydrology may be
affecting the ecological setting have been earlier snowmelt and an increased
proportion of precipitation falling as rain
rather than snow, with forecasts indicating further warming will result
in diminished snow cover and rising snowline
elevation, winter floods, rising water temperatures, recurring droughts,
and lower late season streamflows. Forest
and riparian community shifts could also result in changes in the position,
availability, and quality of energy and
organic matter resource inputs to streams.
The timing, magnitude and variability of the flow regime are integral
to structure and function of stream biological
communities. Biological diversity of endemics in aquatic habitats of the
Sierra Nevada is high, and remains poorly
documented in headwater and alpine streams. Conservation of this biodiversity
cannot proceed with basic survey and
inventory and attention to the varied geospatial influence of climate
change in mountain terrain. How climate
change-induced alteration of hydrological pattern affects the ecology
of mountain streams has not been documented
and no monitoring network in the Sierra is in place to track changes.
What we do know is that temperature and flow
are drivers of life cycle phenology such as growth and timing of emergence
of aquatic insects. Changes in phenology
may further extend into the riparian and terrestrial environment where
availability of emerging adult insects provide
important food-web linkages. Another response to warming climate is range
shifts of temperature-sensitive species
into northern latitudes or higher elevations. Loss of perennial flows
and drying will also result in local extirpations,
particularly the loss of alpine natives and species requiring multiple
years to complete development. In addition to
potential loss of natural biological structure and function as a result
of shifting phenology, range and distribution,
thermal sensitivity, and flow disturbance regime (floods, drought, variability),
such changes may also compromise the
use of stream invertebrate communities as indicators of environmental
quality in regulatory programs (e.g. EPA, USFS,
and SWAMP). Streams with minimal exposure to local disturbance are used
as standards for judging the integrity of
disturbed streams, but the overarching influence of climate change may
result in reduced sensitivity for detecting
impaired water quality and inaccurate assessment of status and trend.
Nested catchments within reference watersheds with differing climate-hydrologic
forecasts may serve as the basis for
detecting stream ecosystem effects of climate change in the Sierra. Legacy
sites with prior data may provide
additional information for assessing long-term trends. Watersheds with
cool microclimates, northern aspects and/or
significant groundwater input may provide thermal refugia controls for
studying climate effects. Use of natural
gradients and experimental manipulations may further contribute to understanding
ecological consequences of
climate change on mountain streams.
HERBST, DAVID B.
Sierra Nevada Aquatic Research Laboratory, University of California, Mammoth
Lakes, CA 93546
One of the anticipated climate change effects on mountain stream hydrographs
is an increase in the frequency of rainon-
snow events occurring in winter and spring. The flooding caused by such
events can be geomorphically
catastrophic, but much less is known about how these floods might affect
aquatic life. The new years day flood of
1997 provided an opportunity to study the composition of benthic invertebrate
communities of 14 eastern Sierra
streams sampled in the summer before and the summer after this record
event. As a contrast to the pulse disturbance
represented by such events, sustained flood or press disturbances occur
in years of high volume spring runoff from
large winter snowpacks. Changes in stream invertebrate communities from
this form of flooding were also studied on
5 streams in four years of alternating average and large snowpack conditions
(1992-1993-1994-1995). Benthic or
bottom-dwelling stream invertebrates have been widely used as indicators
of ecological health and of alteration of the
biological integrity of natural stream and river ecosystems. Results indicate
that little change in the density or
composition of stream invertebrate communities occurred after the catastrophic
flood of 1997, or that there was any
difference as a function of watershed size and stream power (these streams
were, however, mostly of small size).
The press disturbance of sustained spring flooding did appear to alter
some measures of community structure as more
tolerant invertebrates dominated after flood years, but more diverse communities
recovered in average years.
Repeated or prolonged flooding may have more significant impacts, especially
in larger streams, but the smaller
headwater streams studied here appear resilient to this form of disturbance.
Talk*
CLIMATE CHANGE AND CALIFORNIA GULLS AT MONO
LAKE, CALIFORNIA
HITE, JUSTIN (1); NELSON, KRISITIE (2); WINKLER, DAVID (1)
(1) Cornell University, Department of Ecology and Evolutionary Biology,
Corson Hall, Ithaca, NY 14850, (2) PRBO
Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954
Approximately 50,000 California Gulls (Larus californicus) breed at
Mono Lake, California. Analysis of 17 years of
population size data indicates that their population fluctuates most in
relation to (1) density of the Brine Shrimp
population (a primary prey item) near the time of laying and (2) average
air temperature in the month before egglaying.
Both of these conditions could be affected by variability associated with
climate change and negatively impact
California Gulls. Meromixis, or persistent chemical stratification caused
by high freshwater runoff not mixing with
salty lake water, is another threat to California Gulls. Meromixis occurred
twice in the last 25 years, both events
leading to significant decreases in California Gull breeding success in
the initial years of each episode. Gull
productivity rebounded in the latter years of each episode as meromixis
broke down. While meromixis is a natural
condition for Mono Lake it will occur more often at the lake’s current
artificially lowered level, and the frequency of
years with exceptionally high runoffs capable of initiating meromixis
may increase with climate change.
HOLMQUIST, JEFFREY; SCHMIDT-GENGENBACH, JUTTA
University of California White Mountain Research Station, Bishop CA 93514
Arthropods represent a large component of wetland ecosystems in terms
of abundance, diversity, and food web
composition, and we have established two long-term programs (elements
of National Park Service and GLORIA efforts)
designed to test the response of these fauna to climate change and other
possible stressors. Initial data from the
Sierra Nevada and the White Mountains suggest that both terrestrial and
aquatic arthropod assemblages may respond
rapidly to changes in climate, particularly the likely reduction in precipitation
in the form of snow. Data from both
ranges suggest that a wide range of terrestrial arthropod abundance, richness,
and evenness response variables are
positively related to winter precipitation and track annual differences
in snow water equivalent. Reductions in
terrestrial arthropod abundance and diversity in response to reduced winter
precipitation could be exacerbated by a
concomitant shift in meadow vegetation assemblages towards dominance by
plant taxa characterized by lower
productivity.
Anticipating response of fauna to reduced winter precipitation is more
problematic for the aquatic arthropod
assemblages that inhabit the ephemeral snowmelt ponds characterizing these
wetlands in early season. Our initial
results show an inverse relationship between annual snow water equivalent
and per-unit-area faunal abundance and
diversity in these ponds, possibly because larger, more persistent ponds
form following years with heavy snowfall, and
these ponds develop large predator populations that appear to control
other aquatic arthropod populations. Total
flooded meadow area is lower, however, following dryer winters, so, conversely,
overall arthropod abundance and
diversity might be lower under most climate change scenarios. Further,
reduced snowfall and associated ponding and
soil moisture could lead to reduced abundance of some large sedges-- favored
aquatic invertebrate habitat-- and to a
shift towards vegetation with lower productivity and canopy height and
a more depauperate invertebrate assemblage.
Talk*
A PROCESS-BASED MODELING APPROACH TO THE INTERPRETATION OF HIGH-ELEVATION
TREE-RING RECORDS IN THE WESTERN UNITED STATES
HUGHES, MALCOLM K. (1); SALZER, MATTHEW W. (1); FRANKLIN, REBECCA (1);
AMMANN, CASPAR. (2); BUNN, ANDREW G. (3); KIPFMUELLER, KURT F. (4)
(1) Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ
85721; (2) National Center for Atmospheric
Research, Boulder, CO 80307; (3) Department of Environmental Sciences,
Western Washington University,
Bellingham, WA 98225; (4) Department of Geography, University of Minnesota,
Minneapolis, MN 55455
In high, dry environments like those found in the Eastern Sierra and
Great Basin, tree rings record climate variability
in a complex manner. In very broad terms, larger tree rings of a species
like bristlecone pine are produced by wetter
and cooler conditions near the lower elevation limit of the species, and
by warmer and wetter conditions when
growing near the upper limit. The temperature signal tends to be better
expressed at decadal and longer time scales
at the highest elevations, and the moisture signal there at interannual
timescales). These features are apparent in
comparisons with and statistical models using 4-km resolution monthly
PRISM data for the period 1895 to 2006. We
have also reproduced the properties of tree-ring records from the upper
and lower limits of bristlecone pine using a
process-based model of tree-ring growth driven by daily meteorological
data from two high mountain stations,
available from 1956 to 1979 (1977 at the lower elevation). Here we report
the results of efforts to extend these
simulations for a longer period, and apply them to a newly developed elevation
transect of bristlecone pine
chronologies. For this we use output for the years 1870-1999 from a realistically
forced 20th-Century simulation of the
coupled NCAR-CCSM-3 climate model. The implications of these results will
be discussed in the context of recent treering
growth rates in bristlecone pine at the highest elevations that have been
faster than in several millennia.
Plenary Talk*
CLIMATE CHANGE EFFECTS ON HIGH MOUNTAIN FOREST ECOSYSTEMS IN EASTERN CALIFORNIA
HUGHES, MALCOLM K.
Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721
A complex set of climate factors is involved in the control of the establishment,
survival, mortality and growth of
trees, and the structure of their stands, in the high mountains of Eastern
California. These factors vary on many time
scales, from diurnal to millennial, and their impact on ecological processes
differs greatly with elevation, topographic
position and substrate. There are a number of valuable sources of information
on variations in the structure and
growth of the high mountain forests of this region over the last few thousand
years. A variety of explanations have
been offered for these variations, including natural climate variability.
These records, and their interpretations, will
be considered in an examination of the possible climate change effects
on these forests that might be expected this
century and beyond.