CONFERENCE ABSTRACTS & PRESENTATIONS
* invited presentation
Talk*
PREDICTED MULTI-TROPHIC LEVEL RESPONSES OF MONO LAKE TO CLIMATE CHANGE
AND WATER MANAGEMENT
JELLISON, ROBERT
Marine Science Institute, University of California, Santa Barbara, CA
93106-6150
The predicted responses of lakes to climate change are highly lake-specific
and depend on the complex interplay
between hydrology, morphometry, mixing, nutrient cycling, and biotic interactions
within a lake. Salt lakes are
particularly sensitive to climate change as changes in their hydrologic
budgets determine their size, salinity, and
biotic communities. However, water diversions have dominated changes in
the water balances of most large salt lakes
throughout the 20th century. At Mono Lake, past diversions have lowered
the surface elevation to well below its
natural climatic equilibrium and now the effects of decreasing salinity
associated with the current policy of restricting
diversions until an elevation of 6391 ft is reached are predicted to be
much larger than any associated with climate
change.
Limnological monitoring from 1979-2007 has revealed a striking multi-trophic
level response to variation in salinity and
temperature. Adult abundance of the spring generation (May-June) is negatively
correlated with salinity and positively
correlated with March water temperature and phytoplankton abundance. However,
adult abundance of the summer
and autumn populations are inversely correlated with May-June ovoviviparous
reproduction due to a pronounced larval
bottleneck experienced by early instars. Thus, the seasonal abundance
of Artemia has shifted to earlier in the year
(slope, 1.5 days/yr; r2, 0.46) over the 28-year record of varying but
generally decreasing salinities. This seasonal shift
has benefited breeding California Gulls at the expense of autumn staging
and migrating Eared Grebes.
Given the management policy of maintaining a relatively constant surface
elevation once lake levels reach 6391 ft,
the impact of climate change on the lake’s water budget would be
mitigated. However, predicted warming and
increased spring water temperatures will likely cause a further shift
of the seasonal abundance of Artemia to earlier
in the year.
Talk
OBSERVED CLIMATE-SNOWPACK RELATIONSHIPS
IN CALIFORNIA AND THEIR IMPLICATIONS FOR THE FUTURE
KAPNICK, SARAH; HALL, ALEX
University of California, Los Angeles 90095-1565
A study of the California’s Sierra snowpack has been conducted
using snow station observations and modeled surface
temperature data. First of the month snow water equivalent measurements
were combined from two datasets to
provide sufficient data for statistical analysis of the evolution of the
snowpack during the snow season from 1930 to
2007. The temporal centroid of snow water equivalent (“SCD”)
is used to assess variability in the timing and
magnitude of snow accumulation and melt, from February 1st to May 1st.
Since 1930, there has been a trend towards
earlier SCD by 0.4 days per decade. Since 1948, regional March temperatures,
using the NCEP Reanalysis 1 surface
temperature dataset, have increased at a rate of 0.4°C per decade.
The trend in SCD can be explained by its
sensitivity to local March temperatures. The SCD is shown to shift earlier
in the season by 1.3 days per 1°C increase in
March temperatures. Given modeled predictions of future temperature in
California, the peak date may shift by more
than a week by the end of this century.
Talk
WHO'S AFRAID OF THE SNOWBALL EARTH: EARTH'S
FUTURE CLIMATE FROM THE DEEP PAST
KENNEDY, MARTIN
University of California, Riverside, CA
no abstract received
KIRCHNER, PETER; RICE ROBERT; LIU, FENGJING
Sierra Nevada Research Institute, University of California at Merced,
Merced, CA
Rock glaciers are a contributor to base flow and a source of nutrients
in riparian habitats but we presently have little
understanding of the magnitude of this contribution or their biogeochemical
behavior. In this study we investigate
two rock glaciers located in the Southern Sierra Nevada. Water samples
were collected in time series from the
summer of 2006 to 2008 at the outlet of rock glaciers in the Big Pine
Creek and Rock Creek watersheds. Stream stage
and conductivity was monitored at the outlet of both sites. Water samples
were analyzed for conductivity, major
ions, stable isotopes (d18O and dD), and 36Cl. Results at the Big Pine
rock glacier show a distinct shift from snow to
subsurface dominated flows as conductivity increased from 7µs to
62µs and dD increased from -125‰ to -110‰,
indicating subsurface flows originated from the melting ice-core of the
rock glacier. An earlier shift to subsurface
dominated stream flow in 2007 corresponded with a lower than normal snow
pack. Results from the Rock Creek site
showed snow-melt water fractionation values of dD and conductivity values
<10µs indicating little or no melting ice
contributed to the sampled discharge. Nitrate and sulfate concentrations
generally increased seasonally from 5.3µeq
L-1 to 20.5µeq L-1 for nitrate and 3.2µeq L-1 to160.8µeq
L-1 for sulfate indicating the existence of microbial
communities within the rock glaciers. However, these nitrate values are
significantly lower than results from rock
glaciers in the Rocky Mountains where atmospheric contributions to nitrate
formation are higher. Concentrations of
36Cl ranged from 1.5 x106 atoms L-1 to 6.9 x107 atoms L-1 suggesting the
presence of biogeochemical storage sinks or
the contribution of bomb pulse fallout in samples with a large subsurface
component.
KLINGER, ROB (1); OSTOJA, STEVEN (1); BROOKS, MATT (2)
(1) USGS-BRD. Yosemite Field Station-Bishop Office, 568 Central Avenue,
Bishop, California 93514, (2)USGS-BRD.
Yosemite Field Station-El Portal Office
Studies of climate change effects on animals and plants in alpine ecosystems
have been focused principally on
pattern; i.e., expected shifts in species ranges and abundance. However,
the functional consequences to alpine
ecosystems from changes in species distributions have not been addressed
in a systematic or integrated way. Alpine
animals, particularly small and medium-sized mammal species such as pikas,
marmots, and ground squirrels, are
known to play extremely important roles as herbivores and granivores in
alpine ecosystems. While it is widely
assumed that there will be an inevitable, climatically driven transition
of alpine meadows to tree/shrub communities,
interactions between climatic shifts, abundance of mammal species with
different life-history traits, and biotic
processes such as herbivory, granivory, and competition could lead to
multiple pathways resulting in alternative
vegetation states. We have developed a state-transition model representing
eight alternative pathways leading to
four alpine vegetation types: conifer forests (whitebark pine) that have
either a grassy or woody understory, dry
alpine meadows, and wet meadows. The pathways include ones characterized
by strong physical forces (temperature
and precipitation regimes), and those characterized by strong biotic interactions
(seed predation, seed dispersal,
herbivory, and competition). We hypothesize that pathways characterized
by strong physical factors would
deterministically result in just one or two distinct alpine vegetation
types, while those characterized by strong species
interactions would likely result in a mosaic pattern of many alternative
vegetation types. Although largely conceptual
at this point, the model explicitly allows the development of alternative
hypotheses related to direct and indirect
effects of climatic shifts on alpine ecosystems. Moreover, the various
states and transitions of the model can be
quantified, which would facilitate a more mechanistic understanding of
the relationship between climatic shifts,
species additions and deletions, plant-animal interactions, and the stability
of alpine vegetation communities.
KLINGER, ROB; CHASE, JENNIFER; LEE, STEVEN R.; SWINGER, LINDSAY; BRYANT,
JESSICA; LEE, ROBYN; OSTOJA, STEVEN
USGS-BRD. Yosemite Field Station-Bishop Office, 568 Central Avenue, Bishop,
California 93514
While it is widely believed that climate shifts will result in contractions
in range and/or reduced abundance of many
alpine mammal species in the Sierra Nevada and White Mountain ranges,
lack of range wide data on their distribution
and abundance impedes an objective evaluation of the validity of this
belief. We have implemented a ten-year,
multi-scale study of the population dynamics and demography of small alpine
mammals in the Sierra Nevada and
White Mountains, the main goal being a better mechanistic understanding
of the relative influence of direct and
indirect effects of climatic shifts on their distribution and abundance.
Here we present the first year of data (June-
September 2008) on density and habitat associations of the yellow-bellied
marmot, Belding’s ground squirrel, goldenmantled
ground squirrel, and American pika. Rangewide and regional density and
habitat associations were estimated
from a total of 1206 observations recorded on 40 variable-distance line
transect samples totaling 452 km. Estimates
of the probability of local occupancy and detection were obtained from
25 variable-distance points visited 6 times
between June and August 2008. Densities of the yellow-bellied marmot,
pika, and golden-mantled ground squirrel in
the White Mountains were similar to those in the Sierra Nevada. Marmot,
pika, and golden-mantled ground squirrel
densities were generally greater in the southern than the central and
northern Sierra Nevada, while density of
Belding’s ground squirrel was greater in the northern than central
and southern part of the range. However, estimates
of density based on geographic stratification were three times more variable
than estimates stratified by relativedensity. Detection probabilities
for all four species were relatively high (0.69-0.83), but occupancy rates
varied from
less than 0.56 for the pika and Belding’s ground squirrel to 0.88
for the golden-mantled ground squirrel. All four
species showed distinct preferences among vegetation types, with the pika
being most specialized and the goldenmantled
ground squirrel the most general. Although interpretation of data from
just a single year must be made
cautiously, collectively the results suggest models of alpine mammal species
distributions must include variables
representing habitat structure and not simply climate. More generally,
these data indicate that indirect effects from
climate shifts may have as strong or stronger effects on alpine mammal
distributions as direct effects, and these
effects may not necessarily be uniformly negative for all species. We
hypothesize that responses of alpine mammals
to climate shifts may actually be very heterogeneous, with range shifts
or changes in abundance occurring in some
areas but not others and to a greater degree for some species than others.
LACAN, IGOR (1); MATTHEWS, KATHLEEN (2); FELDMAN, KRISHNA (2)
(1) University of California, Berkeley, Department of Environmental Science,
Policy and Management, Berkeley, CA
94720, (2) USDA Forest Service, Pacific Southwest Research Station, Albany,
CA 94701
Annual variation in snowpack (from 20 to 200% of average) and summer
rainfall cause large fluctuations in volume of
small lakes in the higher elevation (>3000 m) Sierra Nevada Mountains,
which are important habitat for the imperiled
Sierra Nevada Yellow-legged Frog, Rana sierrae. Climate change
(global warming) is predicted to increase these
fluctuations, potentially leading to more frequent summer drying of the
shallow, fishless ponds where most R. sierrae
breeding and larval development (requiring =3 years) occurs today. This
study explored the interaction between
water availability and the abundance and recruitment of R. sierrae
in Dusy Basin, Kings Canyon National Park,
California, USA. We mapped the Dusy Basin lakes with GPS, and calculated
water volumes in a low-snowpack year
(2002) and a high-snowpack year (2003), and counted R. sierrae. The lakes
that dried up in 2002 were repopulated by
adult frogs in 2003, without any recruitment of metamorphosed frogs from
previous year’s tadpoles. The lakes that
had retained water, even with notable water-volume decreases (-60%), showed
tadpole-to-subadult recruitment in the
following year (2003). Analogous results are obtained using data for years
1997 – 2006: significantly greater
abundance of metamorphs in permanently wet lakes than in lakes that had
dried even once during the ten years.
Similarly, those lakes that had retained water during any two preceding
years had significantly more metamorphs than
lakes that had dried up during that period. Our results suggest that any
increase in drying of small ponds will severely
reduce frog recruitment. Combined with the invasive fish that prevent
frog breeding in larger lakes, it may lead to
the extinction of local frog populations.
Plenary Talk*
ECOSYSTEM CONSEQUENCES OF PRECIPITATION CHANGE IN EASTERN CALIFORNIA
LOIK, MICHAEL E.
University of California at Santa Cruz, Santa Cruz, CA 95064
Snowfall is the dominant hydrologic input for high elevations and latitudes
of the arid- and semi-arid western United
States. Sierra Nevada snowpack provides numerous important services for
California, but is vulnerable to
anthropogenic forcing of the coupled ocean-atmosphere system. Fundamental
ecological models predict migrations of
species to higher elevations under a warmer climate, but how will changes
in snow depth and melt timing affect soil
and plant water relations, growth, and recruitment for dominant shrubs
and trees at the ecotone between the Sierra
Nevada conifer forest and Great Basin Desert shrubland? And, how do these
processes affect carbon storage and fire
fuel accumulation within these systems? To address these questions, our
experiments utilize large-scale, long-term
roadside snow fences to manipulate snow depth and melt timing. These treatments
affect short-term soil moisture
pulses, and over the long-term, they impacted cover or biomass of Achnatherum
thurberianum, Elymus elemoides,
and Purshia tridentata. Growth of adult Pinus jeffreyi was
sensitive to snow depth, and seedling recruitment was
higher under the Nitrogen-fixing shrub Pu. tridentata. By contrast,
Pinus contorta growth was reduced by both
increases and decreases in snow. Root and litter inputs, as well as soil
carbon and nitrogen content, were different
within intershrub and shrub canopy microsites, and across snow depth treatments.
Results indicate complex
feedbacks between snow depth, soil water inputs, physiological processes,
and population patterns at multiple spatial
and temporal scales, portending trade-offs between future ecosystem carbon
storage and fire fuel accumulation.
Plenary Talk*
MOUNTAIN HYDROCLIMATOLOGY AT ECOSYSTEM
SCALES: WHAT DO WE NEED TO KNOW?
LUNDQUIST, JESSICA D. (1); LOTT, FRED (1, 2)
(1) Civil and Environmental Engineering, University of Washington, Seattle,
WA 98195, (2) Northwest Hydraulic
Consultants, Seattle, WA 98188
In the high desert of the Eastern Sierra, the structure and composition
of mountain ecosystems depends critically on
when snow cover disappears and on when water availability becomes limiting.
Most assessments of climate change
demonstrate a strong understanding of the former, e.g., warmer temperatures
and earlier snow melt, but a weak
understanding of the latter. To accurately model the spatial patterns
and timing of late-summer streamflow and
water availability, we must understand 1) the spatial distribution of
snowfall and resulting snowpack heterogeneity; 2)
the frequency, locations, and intensity of summer precipitation, mainly
thunderstorms; and 3) how vegetation
modulates evapotranspiration in response to increasing vapor deficits
and decreasing soil moisture. Here, we review
current modeling approaches of varying complexity and present innovative
monitoring techniques to learn more about
these processes.
LUTRICK, ERIN (1); HILL, BARRY (2); JACKSON, BENJAMIN (3)
(1) Inyo National Forest, Bishop, California; (2) Forest Service Pacific
Southwest Regional Office; (3) UC Berkeley
school of Environmental Design
With climate change and steadily increasing population, appropriate
management of water from California’s Sierra
Nevada Mountains will be a challenge. With less snowfall and earlier melting,
the snowpack is no longer storing winter
water as long into the dry summer months, and groundwater storage in upper
elevations of the Sierras may become
relatively more important. However, there is little data about groundwater
storage in the Wilderness, headwater
areas of the Sierra Nevada. To help improve knowledge of shallow groundwater
storage, we instrumented three
meadows within the Ansel Adams and John Muir Wilderness, and one adjacent
to the Wilderness in the Upper San
Joaquin River Watershed, to better understand meadow groundwater storage,
streamflow within meadows, and the
effects of meadow degradation on meadow groundwater storage and downstream
flow. This work is being completed
as a part of a CalFed funded Upper San Joaquin Watershed Assessment. We
installed eight to eleven groundwater
monitoring wells and/or piezometers in each of three meadows; Johnston,
Purple, Tully Hole, and Agnew Meadows.
Preliminary results from summer 2008 will be presented, as well as challenges
in completing the work. Challenges
included getting permission from land managers to install temporary structures
in Wilderness, as well as access issues,
and equipment limitations for Wilderness use.
Poster
DESCRIBING FORESTS IN YOSEMITE NATIONAL
PARK WITH ACTUAL EVAPOTRANSPIRATION AND DEFICIT
LUTZ, JAMES A. (1); VAN WAGTENDONK, JAN W. (2); FRANKLIN, JERRY F. (1)
(1) College of Forest Resources, University of Washington, Seattle, WA
98195-2100, (2) USGS Western Ecological
Research Center, Yosemite Field Station, El Portal, California, 95318
Models of water relations have been used to explain tree species distribution,
but these models generally assume flat
terrain and uniform soil water storage making them less useful in mountainous
terrain. We extended a Thornthwaitetype
model by considering differences in water demand based on the local slope
and aspect. We used plot physical
parameters (n = 655) to derive annual water balance. We calculated annual
actual evapotranspiration (AET) as a
proxy for productivity and annual soil moisture deficit (Deficit) as a
proxy for summer drought and used those values
to describe distributions for 17 tree species over the 2,300 m elevation
gradient in Yosemite. We combined
vegetation plot data with precipitation, temperature, soil water capacity,
slope, aspect and latitude data sets of
different resolutions to develop spatially explicit environmental templates
– a potential improvement over models
where all input parameters have uniform grid size. We calculated tree
species biophysical envelopes over broad
ranges of environmental gradients – in this study a range of 31.0
cm for soil water capacity, 33.4 °C for July mean
temperature, and 918 mm yr-1 for annual precipitation were noted. As climate
change involves complex
interrelations between changes in temperature and precipitation, models
using AET and Deficit may allow more
precise predictions of range shifts. We used present climatological averages,
reconstructions of past climate, and
climate projections to evaluate changes in the water balance for locations
where trees of each of 17 species are now
present. Changes in water balance from 1700 (“Little Ice Age”)
to the present are small, but changes between the
present and expected climate in 2050 (1.5 °C warmer) are large and
significant for most species.
Talk
TWENTIETH-CENTURY DECLINE IN LARGE-DIAMETER
TREES IN YOSEMITE NATIONAL PARK, CALIFORNIA, USA
LUTZ, JAMES A. (1); VAN WAGTENDONK, JAN W. (2); FRANKLIN, JERRY F. (1)
(1) College of Forest Resources, University of Washington, Seattle, WA
98195-2100, (2) USGS Western Ecological
Research Center, Yosemite Field Station, El Portal, California, 95318
Between the mid-1930s and the 1990s, the density of large diameter trees
in Yosemite National Park declined 24% (P <
0.001). The decrease was apparent in all coniferous forest types. Proportionate
declines were higher in subalpine
and upper montane forest types, and less in lower montane forest types.
Densities of large-diameter Pinus albicaulis,
Quercus kelloggii, and Q. chrysolepis increased, but densities
of large-diameter individuals declined for eleven other
common species. Three general patterns emerged. For Pinus ponderosa,
P. jeffreyi, and P. lambertiana,
proportional decreases in large-diameter trees were greatest at lower
elevations. For Abies concolor, A. magnifica, P.
contorta, and P. monticola, proportional decreases were
approximately uniform throughout the range. For Q.
chrysolepis, Q. kelloggii, Calocedrus decurrens, P. albicaulis, and
Pseudotsuga menziesii, increases in density of
large-diameter trees occurred only in the upper portions of their ranges.
Within-plot richness, evenness and density
of large-diameter trees decreased for most species and most forest alliances.
The reintroduction of fire to plots in
the Pinus ponderosa mixed coniferous forest alliances did not decrease
the density of large diameter trees compared
to areas that had not burned since 1936. However, unburned plots retained
few large-diameter P. ponderosa; the
large-diameter component shifted to A. concolor, C. decurrens,
and Q. chrysolepis. The result for lower elevation
forests are consistent with increased moisture stress due to increasing
overall tree density and with climate that has
warmed since the establishment of today’s large-diameter individuals.
Results for large-diameter P. albicaulis are
consistent with a calculated recent decrease in annual soil moisture deficit
at higher elevation. Comparisons of past,
present and future climate scenarios with respect to annual actual evapotranspiration
and annual soil moisture deficit
suggest that the climate-driven portion of changes in the structure of
these forests is likely to accelerate over time.
Talk
CLIMATE, LIGHTNING IGNITIONS, AND FIRE SEVERITY
IN YOSEMITE NATIONAL PARK, CALIFORNIA, USA
LUTZ, JAMES (1); VAN WAGTENDONK, JAN (2); THODE, ANDREA (3); MILLER,
JAY (4); FRANKLIN, JERRY (1)
(1) College of Forest Resources, University of Washington, Seattle, WA
98195-2100, (2) USGS Western Ecological
Research Center, Yosemite Field Station, El Portal, California, 95318,
(3) School of Forestry, Northern Arizona
University, Box 15018, Flagstaff, Arizona, 86011, (4) USDA Forest Service,
3237 Peacekeeper Way, Suite 101,
McClellan, California, 95652
Continental-scale studies of western North America have attributed recent
increases in annual area burned and fire
size to a warming climate, but these studies have focused only on large
fires and have left the issues of fire severity
and ignition frequency unaddressed. We examined the relationship between
decreasing snowpack and the ignition
and size of all fires that occurred in Yosemite National Park, California
(area 3,027 km2) between 1984 and 2005.
During this period, 1,870 fires burned a total of 77,718 ha. We quantified
fire severity for the 103 fires >40 ha with
satellite fire severity indices using 23 yrs of Landsat Thematic Mapper
data. Increased spring snowpack exponentially
decreases the number of lightning ignitions (P < 0.001), and the proportion
of the landscape burned at higher
severities increases with the log10 of annual area burned (P < 0.001).
The principal mechanism whereby snowpack
mediates lightning ignitions is through the seasonal landscape flammability.
A secondary mechanism is fewer lightning
strikes in years with higher April 1st snowpack. Future climate-induced
decreases in snowpack and the concomitant
increase in fire severity suggest that existing assumptions about fire
may be understated – future fires may be more
severe, and post-fire recovery may take longer. Using one forecast for
snowpack, we project that the number of
lightning ignitions in Yosemite National Park from 2020 to 2049 will be
19.1% higher than between 1984 and 2005 and
that the annual area burned at high severity will increase 21.9%.
Poster
THE EFFECTS OF HABITAT AMELIORATION AND HERBIVORY ON SEEDLINGS OF PINUS
LONGAEVA
MAHER, COLIN
UC Santa Cruz Department of Ecology and Evolutionary Biology, Santa Cruz,
CA
Survival of conifer seedlings in desert environments can be strongly
influenced by both positive and negative
community interactions. Pinus longaeva (bristlecone pine) trees in the
White Mountains of California produce large
quantities of seeds each year, yet demographic data suggest that successful
recruitment episodes occur only several
times a century. Therefore, it is likely that the germination and survival
of first-year seedlings for this long-lived
species may be critically important elements of population dynamics. To
better understand the factors that influence
the survival of first-year trees, I performed two field experiments with
greenhouse grown P. longaeva seedlings. To
assess the impact of herbivory, I planted seedlings in full cages, open
ended cages (cage controls), and uncaged
treatments in three situations on Campito mountain: within the bristlecone
forest, in the sagebrush scrub slightly
lower in elevation than the current forest, and in the sagebrush scrub
above the current forest. To test the effects of
habitat amelioration by dead wood and sagebrush (Artemisia tridentata),
I planted seedlings in sagebrush scrub in
three caged treatments: underneath sagebrush, in the open spaces between
sagebrush plants, and underneath shade
structures made from blocks of wood. In the first experiment, I found
that seedlings were predated with greater
frequency within the bristlecone forest than in the sagebrush scrub. This
result is consistent with the Janzen-Connell
distance hypothesis and indicates that herbivory is not an important factor
influencing the boundary of the forest. In
the second experiment, I found that mortality was significantly reduced
in seedlings shaded by a block of wood,
indicating that habitat amelioration (e.g., sun and heat protection) provided
by dead wood may be important for
successful seedling establishment. Sagebrush had no significant effect
on survival compared to the exposed intershrub
treatment, suggesting that sagebrush does not facilitate the establishment
of P. longaeva seedlings.
Talk*
CLIMATE CHANGE EFFECTS ON RESTORATION PROCESSES
AND ENDPOINTS IN THE MONO BASIN
MARTIN, DAVID W.
City of Los Angeles Department of Water and Power, Bishop, California
City of Los Angeles Department of Water and
Power, Bishop, California
State Water Resources Control Board Decision 1631 and Order Nos. 98-05
and 98-07 require LADWP to monitor stream
flows, and to restore and monitor the fisheries, stream channels, and
waterfowl habitat. LADWP has focused its
restoration program, on the specific goal of a fully functioning, self
sustaining ecosystem. The streams as they exist
today are closer to that goal than during the years leading up to LADWP’s
diversions, however, changing climate could
substantially affect the ability of various ecosystem components to resemble
what many consider “restored”. The
ability to evaluate and predict how potential climate change scenarios
may affect components of the Mono Basin
ecosystem requires tools that adequately accommodate the complex processes
of ecological dynamics at various
spatial and temporal scales. One tool under development by LADWP is the
application of the Ecological Dynamic
Simulation Model (EDYS) to land and water management to assist managers
in selecting defensible strategies to best
meet difficult management objectives within regulatory constraints and
variable climatic and disturbance scenarios.
EDYS is a mechanistic simulation model that simulates complex ecological
dynamics across spatial scales ranging from
plots to landscapes and watersheds. Modules include climate, hydrology,
soils, nutrient cycles, plant community
dynamics, herbivory, animal dynamics, management activities, and disturbances.
Model scenarios that simulate shifts
in precipitation patterns and altered temperatures are being evaluated
to determine potential effects on riparian and
wetland communities and may be useful in determining appropriate management
approaches for the Mono Basin.
MARTINSON, SHARON J.; LOIK, MICHAEL E.
University of California-Santa Cruz, Santa Cruz, CA
Ecosystems with harsh abiotic conditions tend to have fewer species
than more temperate systems, and the species
that persist in these harsh environments have evolved to tolerate their
conditions. Biotic interactions (e.g.
competition, herbivory, mutualisms) also tend to be very specific, and
can be both directly and indirectly affected by
perturbations to abiotic conditions. The ecosystem of the eastern Sierra
Nevada is shaped by limited precipitation,
predominantly in the form of snow. Great Basin sagebrush, Artemisia
tridentata, a dominant shrub in this ecosystem,
is host to many species of gall-forming insects and other arthropods.
Artemisia-dwelling insects represent a large
portion of the insect biodiversity in this system. The suitability of
A. tridentata as a host for these insects will likely
change under future climate scenarios if the abiotic conditions are different
than those conditions under which these
interactions evolved. Snow precipitation is one condition that is predicted
to change in the future. Host suitability
may depend on the water status of the plant, so future snow conditions
could change the number, diversity or
community composition of insects utilizing A. tridentata. To
determine the effects of increased or decreased snow on
insects, we surveyed the galls on A. tridentata in areas with
experimentally increased or decreased snow. We found
high diversity of gall morphotypes (> than 20), as well as several
species of homopteran herbivores that were tended
by ants. We present patterns of insect diversity suggesting that insects
are sensitive to plant responses to changes in
the snow regime. Ongoing research to determine the underlying mechanism
of this indirect effect includes studying
how plant defense chemistry is affected by snow conditions. We also present
findings suggesting that changes to
plant-herbivore interactions may alter the leaf litter from A. tridentata,
which may affect the fire
Talk*
PREDICTED RESPONSES OF THE CALIFORNIA
GOLDEN TROUT TO CLIMATE CHANGE
MATTHEWS, KATHLEEN R.
USDA Forest Service, PSW Research Station, Albany, CA 94701
The native habitat of the California golden trout (CGT), Oncorhynchus
mykiss aguabonita, currently includes stream
areas on the Sierra Nevada Kern Plateau impacted by cattle grazing. As
a result, some areas have reduced streamside
vegetation (willows or sedge), warmer stream temperature (up to 24°C),
and lower dissolved oxygen (DO) than
restored areas that are typically 2-3°C cooler with higher levels
of DO. Climate change may further compromise CGT
and their habitat in stream areas still subject to cattle grazing with
predicted warmer water temperatures, possibly
lower dissolved oxygen, reduced flow, and increased sediment. In the Golden
Trout Wilderness, where most native
CGT reside, many sections have yet to recover or are currently being grazed
and have shallow, widened, unvegetated
sections that could subject CGT to harmful and possibly lethal levels
of DO and water temperatures. Because the CGT
is a Species of Special Concern and petitioned for USFWS ESA listing,
it will be crucial to monitor changes in riparian
condition and water quality to ensure their survival as warming occurs.
Moreover, the overdue restoration of
vulnerable stream sections must quickly proceed to prepare for climate
warming. Stream monitoring of degraded and
recovering stream sections will compare the temperature, DO, stream depth
and width to determine if potentially
harmful conditions occur so that management actions can be implemented.
While these monitoring actions are
already included in the CGT Conservation Strategy, it will be important
to have frequent assessments and determine if
climate warming further stresses already vulnerable CGT populations on
the Kern Plateau.
Talk*
EXTINCTION AND SPECIATION IN THE NORTH
AMERICAN FLORA IN RESPONSE TO QUATERNARY CLIMATE CHANGES
MCLAUGHLIN, STEVEN P.
PO Box 819, Big Pine, CA 93513
Paleontologists, systematists, and biogeographers have concluded that
both extinction and speciation rates are very
low, around 0.1 to 1.0 extinctions/speciations per species per million
years. There is also widespread consensus that
migration rates in response to climate changes are high. Slow rates of
macroevolutionary change coupled with high
migration rates should produce a biota where most of the species are widespread.
For the North American flora (and
most other biotas), just the opposite is the case: the frequency distributions
of range sizes is highly left-skewed with
many rare and local species and few widespread ones. A transition-probability
model was developed to determine
what extinction, speciation, and migration rates can account for the modern
frequency distribution of range sizes.
The results suggest that thousands of species of plants have originated
and gone extinct with each major cycle of
global climate change during the past 2 million years. Total Quaternary
speciations and extinctions have probably
exceeded 40,000 species. The implications of this research for conservation
will be discussed.
MILLAR, CONNIE; BOB WESTFALL; DIANE DELANY
USDA Forest Service, PSW Research Station, Sierra Nevada Research Center,
Albany, CA
High elevation biota, including subalpine tree species and associated
treeline, are commonly assumed to respond to
global warming by migrating upslope. This assumption generates a conservation
hypothesis that habitat will be lost as
available area diminishes approaching mountain summits, with extirpations
and extinctions as likely consequences. In
recent years we have been studying recruitment, demography, and mortality
of high-elevation forests in the eastern
Sierra Nevada and western Great Basin ranges in response to paleoclimatic
variability (past 3500 years) and to 20thcentury
warming and decadal variability. Conclusions from these studies suggest
that subalpine forest responses to
warming climates are more complex than simple movements upslope. Using
examples from our studies, we propose
the following types of responses to warming temperatures:
I. Subalpine Forest Densification (no treeline change)
A. General Subalpine Forest Infilling
B. Treeline (Ecotonal Zone) Infilling
C. Colonization of Formerly Persistent Snowfields
D. Colonization of Subalpine Meadows
II. Change in Tree Growth & Form (no treeline change)
III. Change in Patterns of Forest Mortality (no treeline change)
A. Change in Drought and Insect & Disease Effects
B. Change in Genetic Diversity & Adaptation
C. Change in Fire Relationships
IV. Change in Geographic Aspect of Forests (no treeline change)
V. Change in Elevation of Forests (with treeline change)
A. Differential Shifts in Elevation by Species (individualistic responses)
B. Shifts Downward in Elevation
C. Synchronous Shifts in Elevation by Multiple Species
MILLAR, CONNIE; BOB WESTFALL; DIANE DELANY
USDA Forest Service, PSW Research Station, Sierra Nevada Research Center,
Albany, CA
American pikas (Ochotona princeps) are small herbivores restricted to
patchily distributed, high-elevation, talus slopes
of western North American mountains. Pikas are vulnerable to brief exposures
of direct heat and warm ambient
temperatures. This condition, coupled with increasing minimum temperatures
during the past 120 years in western
North America, and the geometry of decreasing area on mountain peaks,
has led to the species being considered at
risk from global warming. Increased monitoring has been urged. We documented
325 pika locations during 2007 and
2008 from the eastern Sierra Nevada (Tahoe Basin to Big Pine Cr) and six
western Great Basin ranges (White-, Glass-,
Bodie-, Monitor Pass-, Sweetwater-, and Wassuk Mtn Ranges). We used a
rapid assessment method based on fresh
pellets to find and voucher sites. This method indicates modern usage
but not always current occupation, although at
most sites we also heard or saw pika, or found green vegetation in their
haypiles. The sites ranged from 1827m to
3768m and were distributed on all slope aspects with a slight preference
to NE and E. Over 80% of the sites occurred
in active or relict rock-ice features (RIFs), most commonly rock glaciers
(cirque and valley wall) and boulder stream
landforms. Periglacial RIFs create ideal habitat for pika, including distribution
of rock type and size, cold-air
ventilation in summer and warm-air circulation in winter (Balsch and chimney
circulation), persistent wet meadows at
their base, patches of vegetation scattered on the rock carapace, and
ideal conditions for predator avoidance and den
habitat. Because of their unique air ventilation, RIFs can depress local
permafrost elevations as much as 1000 ft, and
thus provide excellent habitat for pika lower than what might be expected
from average lapse rate gradients. The
climatic envelope of our pika sites (PRISM model) overall averaged 936
mm precipitation (range 279-1610 mm);
minimum temperatures averaged -3.7°C (range -6.8-0.6°C). Relative
to normal distribution, minimum site
temperatures were skewed toward cold values, suggesting a disequilibrium
loss of populations on the warm scale.
Elevation and minimum temperature of pika sites were not significantly
correlated, suggesting that RIF environments
create adequate habitat not strongly related to elevation. Given documentation
by other researchers of extirpations
of low-elevation historic pika populations, in our continuing work we
will emphasize survey of low-elevation RIF sites.
MILLAR, CONNIE; BOB WESTFALL; DIANE DELANY
USDA Forest Service, PSW Research Station, Sierra Nevada Research Center,
Albany, CA
Rock glaciers and related periglacial rock-ice features (RIFs) are abundant
yet overlooked landforms in the Sierra
Nevada, California, where they occur in diverse forms. We mapped 421 RIFs
from field surveys, and grouped these
into six classes based on morphology and location. These categories comprise
a greater range of frozen-ground
features than described in rock-glacier surveys elsewhere. Mapped features
extended from 2225 m – 3932 m (modern,
mean 3333 m), occurred mostly on NNW to NNE aspects, and ranged in apparent
age from modern to relict (late
Pleistocene). Many of the smaller features mapped are not readily discernible
with remote (e.g., air photo)
observation; field surveys remain the best approach for their detection.
We interpreted the presence of outlet
springs, basal lakes, suspended silt in outlet streams, and fringing phreatophytic
vegetation, in addition to
morphologic indications of current rock movement, as evidence for interstitial
ice, either persistent or seasonal. The
six classes were distinct in their geographic settings and morphologic
conditions, indicating process-level differences.
To assess modern climate, we intersected mapped locations with the 30
arc-sec PRISM climate model. Discriminant
analysis indicated significant differences among the climate means of
the classes with the first three canonical vectors
describing 94% of the differences among classes. Mean annual air temperatures
(MAAT) for modern features ranged
from 0.3°C to 2.2°C; mean precipitation ranged from 1346 to 1513
mm. We calculated differences between modern
and Pleistocene temperatures in two ways, one based on elevation differences
of modern and relict RIFs (662 m) and
standard lapse rate, the other using PRISM estimates. For the first, we
estimate the difference in MAAT as -3.9°C
(range -2.2 to -7.9°C); from PRISM, the difference was -3.3°C
(range -1.0 to -6.1°C). In that persistent snowfields and
glaciers are retreating in the Sierra Nevada under warming climates, RIFs
will likely become increasingly important in
prolonging water storage during the warm season and providing small but
distributed water reserves for biodiversity
and runoff. Their presence and water contributions would benefit by further
hydrologic study.
MILLIRON, CURTIS
California Department of Fish and Game, Fisheries Branch, 830 S Street,
Sacramento, CA 95814
In keeping with its mission, the California Department of Fish and Game
is committed to minimizing the effects of
climate change on the state’s natural resources through the development
of adaptation and mitigation measures,
policies, and practices that provide clear benefits to fish and wildlife
and recognize the uncertainty associated with
future climatic states. We are working to identify, respond, and prepare
for climate change through landscape scale
efforts. See www.dfg.ca.gov/climatechange/.
Managing Eastern Sierra Nevada high elevation aquatic resources, including
introduced trout fisheries and native
mountain yellow-legged frogs, is accomplished through the development
and implementation of fisheries and aquatic
biodiversity basin management plans. The aim is to support robust populations
of fish, wildlife, and natural
communities for their intrinsic and ecological values and their benefits
to people. Some non-native fish populations
are being removed to benefit key native species. Where recreation is the
preferred management direction, lakes may
continue to be stocked with hatchery fish, if needed to support quality
fisheries.
Recognizing that emerging climate change science brings uncertainty,
climate models generally predict reduced
snowpack and warmer water temperatures for the Sierra Nevada. Basin management
planning must anticipate
changing conditions, respond to new information and resource monitoring
data, and remain adaptive to meet the
following Eastern Sierra High Mountain Lakes project goal: Manage high
mountain lakes and streams in a manner which maintains or restores native
biodiversity and habitat quality, will support viable populations of native
species, and provides for recreational
opportunities considering historical and future public use.
MOLOTCH, NOAH P.; KWOK, ANGEL; MARGULIS, STEVEN; DOZIER, JEFF
Jet Propulsion Laboratory, California Institute of Technology, Pasadena
CA, 91109
Hydroclimatological studies of snow cover depletion are now possible
as we approach the first decade of Moderate
Resolution Imaging Spectroradiometer (MODIS) snow cover observations.
Previous studies at watershed scales have
shown that these observations can be combined with spatially distributed
snowmelt models to reconstruct the spatial
distribution of snow water equivalent (SWE). We extend this approach using
a Bayesian SWE reconstruction technique
which combines time-series of remote sensing estimates of SCA with a land
surface model (LSM) to estimate stormspecific
snowfall distribution with a retrospective data assimilation scheme. This
approach exploits the inherent
relationship between the timing of snow disappearance and the magnitude
of initial SWE. In this regard, we show that
the MODIS snow cover depletion record from 2001 - 2007 exhibited considerable
interannual variability in both snow
cover persistence and reconstructed snow water equivalent. During wet
years (2005-2006) snow cover persistence was
up 2 - 3 months longer than the average persistence over the observation
period 2001 - 2007. Conversely, in the
drought year of 2007 snow disappeared approximately two months prior to
the average date of snow disappearance.
Reconstructions of snow water equivalent were consistent with the snow
cover persistence anomalies. These snow
cover persistence patterns and associated SWE reconstructions provide
a means to explore spatially explicit trends in
snow accumulation and associated local and meso-scale controls.
Talk*
POPULATION DYNAMICS OF MULE DEER IN THE SIERRA NEVADA: INFLUENCE OF DENSITY
AND CLIMATE
MONTEITH, KEVIN (1, 2); PIERCE, BECKY (1); BLEICH, VERN (2); STEPHENSON,
THOMAS (1); KONDE, LORA (1)
(1) California Department of Fish and Game, Bishop, California; (2) Department
of Biological Sciences, Idaho State
University, Pocatello, Idaho
Current models for climate change indicate increases in temperature
over the next century. Consequently, a better
understanding of the complex associations of large-scale climate regimes,
local weather patterns, and ecological
processes is necessary for both theoretical and applied science. Research
to date has indicated, conclusively, that
climatic variability impacts population dynamics and timing of life-history
events in large herbivores. Large herbivores
have been the focus of such research because herbivores are dependent
on a variety of vegetative communities and
are sensitive to changes in landscape and vegetation characteristics influenced
by climate change. Furthermore, large
herbivores function as keystone species, and understanding herbivore response
to climate change may provide insights
into effects on whole ecosystems. We investigated long-term relationships
between the El Nino southern oscillation,
precipitation, and population dynamics of a migratory mule deer (Odocoileus
hemionus) herd that spends winters at
low elevation (< 1800m) on the eastern side of the Sierra Nevada in
Round Valley near Bishop, California, and spends
summers at high elevation (> 2200m) in the Sierra Nevada on both sides
of the Sierra crest. Population dynamics of
mule deer were influenced by density-dependent factors such as competition
for forage, particularly on winter range,
and density-independent factors such as local weather patterns and large
scale climate. We discuss the interaction of
density independent and density dependent factors on mule deer population
dynamics and the implications of global
climate change on mule deer populations in the Sierra Nevada.
Talk*
RETHINKING RARE SPECIES PERSISTENCE: WHAT FRAMEWORK BEST PROVIDES FOR
ASSESSING RISK AND
PRIORITIZING MANAGEMENT
MOORE, PEGGY
U.S. Geological Survey, Western Ecological Research Center, Yosemite Field
Station, El Portal, CA 95318
Several frameworks have been offered to structure our thinking about
rare plants in terms of type of rarity and in
terms of patterns of rarity. However, few of these have addressed issues
of conservation biology. Stebbins and Major
(1965) provided us with a classification of California’s rare species
based on their evolutionary history. Drury (1980)
and Rabinowitz (1981) used patterns of distribution and abundance to identify
rarity classes. Such approaches can
provide the basis for protecting classes of species, but they may not
be helpful in assessing risk to taxa from
anthropogenic impacts. Climate change impacts on rare plants include altered
fire regimes, habitat fragmentation,
pollinator shifts, and plant community reassembly. Each of these has different
implications for species with different
life histories. Farnsworth and Ogurcak (2008) used collection and visitation
records to identify life-history
characteristics and ecological affinities that may place species at risk
for decline. These included pollination mode,
dispersal strategy, and wetland status. More than evolutionary reasons
for rarity or classes based on rarity patterns,
this kind of approach may provide the best chance of identifying species
vulnerable to climate change effects.
Talk*
LONG-TERM MONITORING IN RIPARIAN HABITATS
IN THE CONTEXT OF CLIMATE CHANGE
MOSS, STELLA; HEATH, SACHA; GEUPEL, GEOFFREY R.
PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954
Although riparian areas account for less than 1% of the western U.S.
landscape, they provide breeding and migratory
habitat for disproportionately more bird species than surrounding uplands.
Thus, loss of riparian habitat has been
implicated as a key factor in western North American bird population declines,
and riparian areas have been identified
as critical habitat for avian conservation in California. For seven years,
PRBO Conservation Science has conducted
demographic monitoring in riparian habitats at Mono Lake. This work has
used standardized methods that allow us to
evaluate changes in riparian bird communities that have occurred as a
result of riparian restoration. Yellow Warblers
(Dendroica petechia) are a good example of a species that is quick to
respond to restoration activities. Twenty years
ago, Yellow Warblers were documented as absent nesters on Rush Creek,
today we found that Rush Creek harbors the
most abundant and densest breeding population documented in California.
However, patterns of bird response to
riparian restoration may be altered by climate change as shifts in migration
timing, initiation of breeding and
elevation and latitudinal distributions occur. These changes can only
be monitored over long periods of time in a
standardized way while keeping in mind that other factors (e.g. land use
and habitat restoration) are also important.
Standardized, long term monitoring will be the foundation to understanding
changes in avian distribution in the
Eastern Sierra and through out California.
Talk*
INTEGRATED BIRD MONITORING IN THE EASTERN
SIERRA: METHODS AND APPLICATIONS
MOSS, STELLA (1); HEATH, SACHA (1); SEAVY, NATHANIEL E. (1, 2); GEUPEL,
GEOFFREY R. (1)
PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954,
(2) Information Center for the
Environment, University of California, Davis, CA 95616
Bird monitoring in the Eastern Sierra can contribute to our understanding
of ecological change. An integrated
monitoring scheme that samples both population trends and demographic
parameters of populations across broad
geographical regions and local microhabitats is important. Trend monitoring
of multiple species can provide
information on groups of species that respond to the same ecological drivers.
Demographic monitoring provides more
detailed information about the contribution of survival and fecundity
to the observed trends. Since 1998, PRBO
Conservation Science has collected baseline data on bird populations along
a more than 300km long stretch of the
Eastern Sierra. In this effort, we have employed standardized protocols,
utilized both volunteers and professionals,
and provided regular results to management agencies. Our monitoring has
documented, amongst other things, the
response of riparian birds to the restoration of Mono Lakes tributary
streams and the potential for conifer
encroachment to change bird communities associated with aspen habitat.
Today, our efforts provide a model for bird
monitoring that can document the ecological effects of climate change
on Eastern Sierra’s bird communities.
MROFKA, DAVID; KENNEDY, MARTIN
Department of Earth Sciences, University of California, Riverside
The record of Cenozoic climate change in the Sierras is unparalleled
because of the combination of clear and
unequivocal glacial deposits and landforms, long-term proxy records of
climate change bound within glacial and
closed-system playa lake deposits and abundant evidence for interaction
between past climates, lake levels and floral
and faunal diversity. This climate record also shows an intimate association
with abundant volcaniclastic deposits that
often bound and interbed with glacigenic deposits but have failed to provide
the hoped-for radiometric age
constraints that would clearly define ages for what appear to distinct
generations of glacial advance and retreat over
the prior ca. 760ka. This lack of radiometric age constraints has led
to a reliance on more indirect dating methods
(i.e. dating carbon in tills and lake-terrace deposits) that, while providing
evocative age data, are problematic and
fail to deliver the resolution that provides unequivocal correlation with
well-understood global climate events during
the Pleistocene. Only 70 km to the southeast, the Death Valley region
contains a similar interval of intimately
associated glacigenic and tectonic deposits recording of what was likely
the Earth’s most severe period of cold climate
conditions and most abrupt and largest magnitude transition from nearly
world-wide glaciation to a greenhouse
climate, during the Cryogenian Period from 850-630 Ma. As in the Sierras,
resolution of distinct climate events has
been frustrated by a lack of radiometric age constraints and correlation
with other global events of the same age
relies upon geochemical proxies and the coincidence of “events”
between similar aged deposits worldwide. We show
here that preservation of Cryogenian glacigenic deposits in Death Valley
is controlled by local tectonism and absent
radiometric age constraints should not be correlated with other deposits
globally based solely on geochemical proxy
data and the coincidence of glacigenic intervals in the stratigraphic
section.
Talk*
DEVELOPING A LONG-TERM MONITORING PROGRAM
IN SIERRA NEVADA NETWORK NATIONAL PARKS
MUTCH, LINDA (1); ROSE, MERYL GOLDIN (2); HEARD, ANDREA (1); GRABAN,
SANDRA (1); CHOW, LESLIE (1)
(1) Sierra Nevada Network, Sequoia and Kings Canyon National Parks, 47050
Generals Highway, Three Rivers, CA,
93271 (2) Sierra Nevada Network, Yosemite National Park, P.O. Box 700,
El Portal, California, 95318
The Sierra Nevada Network (Devils Postpile National Monument, Sequoia
and Kings Canyon and Yosemite National
Parks) is one of 32 Inventory & Monitoring networks across the National
Park Service, established to do baseline
biological inventories and develop and implement well-designed, natural
resource monitoring programs. The network
has completed a multi-year planning effort that engaged parks and outside
scientists, and we are currently developing
detailed monitoring protocols for vital signs (i.e., ecological indicators)
selected for monitoring. To prioritize vital
signs, park, network, and local USGS staff considered each vital sign’s
ecological importance, management priorities,
and sensitivity to large-scale stressors such as climatic change, air
pollution, altered fire regimes, non-native species,
and habitat fragmentation. Vital signs selected include: weather/climate,
snowpack, water chemistry, surface water
dynamics (hydrology), amphibians, bird populations, wetland plant communities,
wetland water dynamics, wetland
invertebrates, forest dynamics, fire regimes, invasive non-native plants,
and landscape mosaics. The network has
completed its bird and lake protocols, and is currently implementing lake
monitoring (water chemistry, hydrology, and
amphibians) in 3 parks. We are also field-testing our wetlands protocol.
Other monitoring protocols are in various
stages of development. Challenges of developing a well-designed monitoring
program with broad spatial inference in
large–predominantly Wilderness–parks will be discussed.
Talk*
THE PROGNOSIS OF ENDEMIC FISHES COMPLICATED
BY CLIMATE CHANGE IN THE WESTERN GREAT BASIN
PARMENTER, STEVE
California Department of Fish and Game, Bishop, CA
Climate change models suggest hotter and drier conditions will prevail
in the eastern Sierra Nevada and western Great
Basin. Model analysis of stream temperature dynamics in two California
streams suggests these changes by themselves
will not increase water temperatures above critical thermal maxima for
the region’s endemic and introduced fishes.
Edaphic factors do not currently drive the contemporary lower elevation
limits of the native fishes. Four endangered
and two species of special concern are confined to hydrologically isolated
refuges, having been excluded from their
natural habitats by introduced predatory fishes. These refuges are vulnerable
to ontogenetic change, biological
invasion, and the genetic consequences of small population size; and tend
to manifest a short population half-life.
Current conservation practice attempts to offset the instability of small
refuges with redundancy, however, the supply
of suitable refuge sites is exhausted and the status of species needing
refuges has not been stabilized. A majority of
refuges for valley-floor species are supplied by spring flow from poorly
understood aquifers. Reduced recharge from
protracted drought, or regional reduction in precipitation, could eliminate
certain critical habitats and magnify the
uncertainty implicit in the existing management strategy. The shortage
of suitable refuge sites may be eased by
ongoing biopolitical initiatives, or by broader consideration of out-of-range
translocations. On a Pleistocene temporal
scale, range extension into selected naturally inaccessible habitats may
offer the greatest potential for insulating
local fish species richness from the combined effects of past anthropogenic
insults and climate change.
Poster
AQUATIC MACROINVERTEBRATES IN MONTANE AND SUBALPINE WETLANDS: ASSEMBLAGE
STRUCTURE AND INFLUENCE OF HABITAT TYPE AND WATER FLOW (jpeg image
file)
PIEROTTI, LYRA; HOLMQUIST, JEFFREY; SCHMIDT-GENGENBACH, JUTTA
University of California White Mountain Research Station, Bishop CA 93514
Temporary waters in montane and subalpine wetlands produce abundant
macroinvertebrate fauna that connect
aquatic and upland habitats via a variety of ecosystem services. We surveyed
aquatic invertebrate assemblages in
wetlands of Sequoia and Kings Canyon National Parks in order to assist
the National Park Service with development of
a long-term monitoring plan. The program will also monitor terrestrial
invertebrates, vegetation, and hydrology in an
effort to track the effects of climate change and other stressors in montane
and subalpine wetlands. Habitats of
interest included fens, wet meadows, and an intermediate type ("peat
accumulating wetlands"), and habitat type was
one of the variables upon which our random sampling was stratified. We
sampled forty-one widely-distributed
backcountry sites during the summer of 2008. We established a plot at
each site to characterize the plant
assemblage, and the nearest temporary water was sampled using a D-frame
net. Flow of the sampled temporary
waters was typically either zero or very low (<1 cm/sec).
Forty families from thirteen orders were represented in our macroinvertebrate
collections. The samples were
dominated by clams and Diptera (particularly midges), but beetles (particularly
predaceous diving beetles), mayflies,
and mites were also common. Despite the high mean abundance of clams,
variance was high, and clams only occurred
in 63% of the samples. Neither assemblage-level nor population metrics
were significantly related to habitat type (3x2
ANOVAs; three habitat types and flow/no flow). In contrast, water flow
was a significant influence on a variety of
metrics, including family richness (Margalef's corrected), percent Ephemeroptera-Plecoptera-Trichoptera
(mayflies,
stoneflies, and caddisflies), and clam, mite, mosquito, and caddisfly
abundances. There was also a significant overall
influence of flow, but not habitat type, across all examined response
variables (sign tests). Water flow appears to be
a more important factor than habitat type in structuring these temporary
wetland assemblages.
PITTERMANN, JARMILA (1)
Department of Ecology and Evolutionary Biology, University of California,
Santa Cruz, CA, 95060
Conifers are a dominant element of the north temperate flora where they
occupy a broad spectrum of habitats. By
contrast, southern hemisphere conifers form a smaller component of the
native forests and are thought to be
relictual. However, it is generally agreed upon that conifers succeed
in climates frequently characterized by poorquality
soils, extreme temperatures and variable water availability. All of these
factors can impair water transport by
triggering air-entry and its subsequent expansion in the water column,
a phenomenon commonly referred to as
embolism. Conifers have evolved a suite of xylem patterns designed to
reduce their vulnerability to drought- and
freezing-induced embolism, so what are the hydraulic trade-offs associated
with resistance to this stress? Freezethaw
cycles can trigger embolism when air freezes out of the xylem sap and
forms a bubble that can expand under
sufficient negative xylem pressure. Here, I present data to show that
this is much more likely to occur as tracheid
diameter increases, creating a direct tradeoff between conducting efficiency
and vulnerability to freezing-induced
xylem failure. Drought-induced embolism is created by air-entry into the
conduit via the inter-tracheid pit membrane
and no clear trade-off exists at the pit level. However, tracheid walls
require sufficient fortification to resist
implosion under negative pressure, which translates into greater carbon
costs and reduced tracheid lumen diameter.
Consequently, reduced water transport efficiency is also correlated with
drought-induced embolism resistance. The
relationship between transport efficiency and resistance to drought-induced
embolism appears to be de-coupled in
southern hemisphere conifers belonging to the Cupressaceae, Podocarpaceae
and Araucariaceae. This suggests that
phylogenetic constraints may preclude these taxa from optimizing the structure-function
of their xylem.
Talk*
TIME DOMAINS OF BIOLOGICAL RESPONSES TO
GLOBAL ENVIRONMENTAL CHANGE
POWELL, FRANK L.
White Mountain Research Station and Dept. of Medicine, UC San Diego, La
Jolla, CA 92093
Physiology determines the direct effect of any environmental change
on a plant or animal. Hence, the biological
consequences of global change in the environment depend upon the relationship
between the rates of environmental
change and physiological responses to the change. Of course, this relationship
is modulated by other factors,
including an organism’s ability to modify its environment (behavior),
changes in the acute physiological response
(acclimatization), genetic changes through evolution (adaptation), and
secondary changes in the environment that
affect all of the above (ecology). All of these factors operate over different
time domains, from seconds to
generations, which further complicates predicting the biological consequences
of global climate change. One
approach to this problem is to study biological responses to other global
environmental changes occurring over the
history of life on earth. Oxygen levels in the atmosphere have varied
between 13% and 30% over the past 600 million
years. Rapid and large changes in atmospheric O2 levels correlate with
profound changes in animal life. Notable
examples include insect gigantism 300 million years ago when O2 was at
its peak and massive extinctions when O2
plummeted to its nadir in the Permian 250 million years ago. More rapid
changes in environmental O2 have occurred
with mountain building and still more rapid changes have occurred in terrestrial
environments with migrations and
currently in marine environments with eutrophication of coastal waters.
The rates of behavioral, physiological,
evolutionary and ecological responses to O2 change can all be measured.
Therefore, it should be possible to test
various models that predict the biological effects of environmental O2
change based on interactions between the rate
of change and rates of response. Such models may be useful for predicting
the consequences of other changes such as
the current change in global climate.
Poster
AEOLIAN ADDITIONS: THE DOWNWIND EFFECTS
ON SOIL AND VEGETATION IN OWENS VALLEY
QUICK, DAYNA J. (1); REHEIS, MARITH C. (2); STEWART, BRIAN W. (3); CHADWICK,
OLIVER A. (1)
University of California, Santa Barbara, Santa Barbara, CA 93106, (2)
U.S. Geological Survey, Denver, CO 80225, (3)
Department of Geology and Planetary Science, University of Pittsburgh,
Pittsburgh, PA
We present results from an ongoing study of soil-ecosystem responses
to dust flux from Owens Lake Playa in Owens
Valley over the past century. Our goal has been to document the spatial
impact of the dust by explicitly considering
distance from the playa and the contrast between the chemistry and mineralogy
of the playa derived dust and the
background, regional dust rain that has impacted the soils at least during
the Holocene. We have sampled soils along a
transect running from north to south along the valley axis to compare
accumulation of salts and fine-grained minerals
both with respect to dust trap samples collected by the US Geological
Survey and with respect to distance from the
playa source for the dust. These sampled soils are from sites selected
on alluvial fan deposits emanating from the
Sierra Nevada Batholith granites. We know that there is a distinct contrast
in trace element chemistry, Sr isotopic
composition and particle size among the granitic parent material, the
playa sediments and the regional dust rain.
These contrasts will allow us to develop quantitative estimates of not
only the role of salts and fines in the soil
profiles and in plant leaf chemistry but also to assign fractions of contribution
from different sources. Early results do
demonstrate a higher level of salts in soils adjacent to the playa, as
well as a clear Sr signature from the playa. Our
results will move the analysis of the prodigious dust clouds that are
thought to impact human health to an analysis of
their impact on the ecosystems of Owens Valley. An evaluation of the severity
of that impact is a critical step toward
assessing management decisions related to Owens Lake Playa as well as
other similar dust sources such as the Salton
Sea that may become desiccated in the future.
RANK, NATHAN (1,3); DAHLHOFF, ELIZABETH (2,3); SMILEY, JOHN (3)
(1) Sonoma State University, Rohnert Park, CA 95472, (2) Santa Clara University,
Santa Clara CA, (3) White Mountain
Research Station, Bishop, CA 93514
Fluctuations in natural populations are thought to depend on an interaction
between the local environment and the
genetic characteristics of the species that in inhabit it, yet there is
surprisingly little empirical evidence to support
this hypothesis. Sierra Nevada populations of the leaf beetle Chrysomela
aeneicollis fluctuate greatly in abundance
among years and these fluctuations often result in local extinction. To
assess the relationship between local
environment, genetics, and abundance, we have quantified environmental
temperatures, population genetics, and
beetle abundance in three neighboring drainages in the eastern Sierra
Nevada (Big Pine Creek, Bishop Creek, and Rock
Creek). We have conducted population genetic surveys since 1988 and assessed
population sizes annually since 2000.
Over the past 10 years, we have also recorded air temperatures in each
drainage. Analysis of variation at mtDNA loci
suggests that migration among drainages rarely occurs, and this is supported
by census data that show that
populations fluctuate independently in each drainage. We have observed
a gradient in allele frequency at the enzyme
locus phosphoglucose isomerase, which coincides with a north-south temperature
gradient. PGI allele 4 predominates
in Big Pine Creek, the warmest drainage and allele 1 predominates in Rock
Creek, the coolest drainage. Allele
frequencies are intermediate in Bishop Creek. We also found that PGI allele
1 increased in Bishop Creek over 8 yrs
when conditions were cool and wet. During a single summer, PGI allele
1 increased in frequency during the early
summer, and PGI allele 4 increased when conditions were warmer. We used
path analysis to integrate the
environmental and genetic influences on population genetics and found
that temperature and PGI variation both
played an important role.
Plenary Talk*
CLIMATE MONITORING AND TRENDS IN THE
CENTRAL AND SOUTHERN SIERRA NEVADA
REDMOND, KELLY T. (1); ABATZOGLOU, JOHN T (2)
(1) NOAA Western Regional Climate Center, Desert Research Institute, Reno
NV 89512-1095, (2) Department of
Meteorology, San Jose State University, San Jose CA 95192-0104
As a contribution to CIRMOUNT (Consortium for Integrated Climate Research
in Western Mountains), several new highelevation
climate monitoring stations have been deployed or augmented in recent
years. These are intended to
complement and extend efforts at low-to-mid elevations. Another dense
network with high temporal resolution was
deployed for studies of mountain waves in the atmosphere (TREX), and has
been gathering data in the Owens Valley
near Independence for four years. Measurements from these and other platforms
now have sufficient length to begin
to offer insights into climate behavior in these locations. Reanalysis
data sets show annual climate warming at the
higher elevations. The rate of warming is not uniform in time, and varies
considerably by season and by month. At
higher elevations, spring shows the greatest warming (though with recent
interruptions), winter shows somewhat less,
and autumn shows almost no warming; summer has shown little warming until
the turn of the new millenium. In
recent years, greater annual warming is seen at higher elevations than
at lower elevations. Reanalysis data can be
used in concert with in situ surface measurements to reconstruct missing
periods, and earlier periods prior to station
establishment. Reanalysis data are based primarily on upper air measurements;
surface-based data for the Sierra
Nevada show similar trends. Not all stations necessarily show warming.
Issues relating to the interpretation of these
records will be discussed.
Talk*
CLIMATE INFORMATION NEEDS FOR THE NATIONAL
PARK SERVICE IN THE SOUTHERN SIERRA NEVADA
REDMOND, KELLY T.; EDWARDS, LAURA M.
NOAA Western Regional Climate Center, Desert Research Institute, Reno
NV 89512-1095
An assessment was performed to evaluate the adequacy of climate data
and monitoring for the Yosemite, Devils
Postpile, Kings Canyon and Sequoia units of the National Park Service
(NPS) as part of their Inventory & Monitoring
Program. Climate data and information are important for operations, research,
and the interpretive mission of NPS,
and for planning by visitors. NPS units generate weather and climate data
themselves, act as hosts for other
monitoring activities, and make use of data and information from nearby
sites outside park boundaries. Geographic,
elevational, and biome coverage was examined. Other topics covered included
the length and quality of records, the
level of redundancy and backup, and the ability to detect climate change.
A correlation analysis was performed for
temperature and precipitation. This included monthly, seasonal and annual
averages and totals, and revealed patters
related to elevation, to east-west (cross-Sierra and Sierra Nevada-Central
Valley) location, and to north-south
(Sequoia-Yosemite) location. The major findings of this study will be
discussed.
Talk*
PEAK FLOW FORECASTING AND MANAGEMENT OF MONO
LAKE’S TRIBUTARIES
REIS, GREGORY J. (1); VORSTER, PETER (2)
(1) Mono Lake Committee, Lee Vining, CA, (2) Consulting Hydrologist, Oakland,
CA
State Water Resources Control Board Decision 1631 and Order Nos. 98-05
and 98-07 require the Los Angeles
Department of Water and Power (LADWP) to release specified peak flows
on Rush Creek, Parker Creek, Walker Creek,
and Lee Vining Creek. Except for Rush Creek, these creeks have no LADWP-controlled
storage and Parker and Walker
Creeks typically remain undiverted. Lee Vining Creek requires accurate
peak flow forecasting and flexible, adaptive
management of water diversions since LADWP is required to allow Lee Vining
Creek’s primary peak to pass undiverted,
while diversions are generally maximized through the rest of the snowmelt
runoff period to fill Grant Reservoir,
augment Rush Creek peak flows and for export to Los Angeles. LADWP forecasts
each year’s peak flow based on data
from previous years, however, real time management of the peak requires
knowledge of the current weather,
snowpack, and upstream reservoir conditions. The Mono Lake Committee makes
peak flow management
recommendations to LADWP by tracking several indicators of snowmelt runoff
to develop forecasts of peak flow
timing. The indicators are combined into a “snowmelt index,”
the relative magnitude of which indicates increasing or
decreasing flow. Peak flows can be forecasted when indicators exceed certain
thresholds, including loss of snow water
content from snow pillows, hours above freezing for certain weather stations,
and days of above specified nighttime
low temperatures at various stations. We are investigating whether the
forecasts can be improved with GIS data to
assess soils, aspects, and elevation bands within the Lee Vining Creek
drainage.
ROBERTS, SUSAN L.
US Geological Survey, Western Ecological Research Center, Yosemite Field
Station, Wawona, CA 95389, USA
Ecosystem function and persistence depend on a variety of ecological
processes being intact and resilient. Feedback
loops are integral to these dynamic ecological processes and a change
in one or more feedbacks requires adjustments
in other feedbacks in order for the process to continue generating a functioning
ecosystem. Climate affects numerous
ecological processes, many of which shape habitat structure and composition.
Habitat structure and composition
determine ecosystem inhabitants, who are themselves a loop in the feedback
of the system and perform important
ecological processes such as seed dispersal, food production, or population
stability. As research begins to show
changes in weather, patterns of snow accumulation, and vegetation distribution,
we are left with the question; how
do these changes affect the animals that rely on these changing habitats?
Predators, whether they are at the center
of the food web or on the edges, can only persist with the occurrence
of stable prey abundance in conjunction with
the presence of specific habitat requirements such as den sites or hunting
perches. As the habitat requirements vary
between different predator and prey species, climate changes resulting
in changes in the physical environment or
habitat structure will most likely create species-specific, idiosyncratic
results. To promote functioning predator-prey
systems in a changing climate, we need to determine what habitat requirements
provide resiliency in the system and
ensure animals have access to these requirements. It is important to maintain
spatial continuity between changing
habitats to ensure predators can pursue their prey as both predator and
prey seek suitable areas to rest, forage, and
reproduce.
Talk
GLACIAL CHRONOLOGIES ALONG THE EASTERN SIERRA
NEVADA FROM BE-10 SURFACE EXPOSURE DATING
ROOD, DYLAN H. (1, 2); BURBANK, DOUGLAS W. (2); FINKEL, ROBERT C. (3)
(1) Center for Accelerator Mass Spectrometry, Lawrence Livermore National
Laboratory, Livermore, CA 94550; (2)
Department of Earth Science, University of California, Santa Barbara,
CA 93106; (3) Department of Earth and
Planetary Science, University of California, Berkeley, CA 94720
A deeper understanding of the timing and extent of global paleoclimate
variations includes knowledge of the age,
duration, and extent of alpine glaciations around the world. Cosmogenic
nuclide surface exposure dating allows more
accurate, high-resolution chronologies in the 100-100,000 year temporal
window to be developed for geomorphic
features that serve as records for past alpine glaciations. Our Be-10
results include ages for glacial landforms along
the eastern Sierra Nevada between Sonora Pass and Mono Basin (including
deposits in the West Walker River, Buckeye
Creek, Robinson Creek, Green Creek, Virginia Creek, and Mill Creek catchments).
We produced >100 Be-10 ages for
boulder samples and depth profiles from 8 glacial moraines and 4 outwash
terraces spanning MIS 2 through 6. Our data
for the Last Glacial Maximum (MIS 2) are remarkably tightly clustered
and support a central age with a small error ~3-
6%; e.g. 17.2 +/- 0.5 ka and 19.5 +/- 1.2 ka). A similar clustering even
holds for an outwash surface associated with
the penultimate glaciation (MIS 6) for which the error is ~7% (136 +/-
10 ka). Our results generate within the study
area a paleoclimate record spanning the past >100 ky using Be-10 that
allows comparison to LGM and older glacial
chronologies and proxy records globally. Also, recent work at CAMS-LLNL
demonstrates the feasibility of dating
Holocene moraine sequences in the Sierra Nevada during time periods when
radiocarbon dating methods are limited
(e.g. the Little Ice Age).
ROVITO, SEAN M.
Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720-3160
The Mt. Lyell Salamander (Hydromantes platycephalus) is endemic to the
Sierra Nevada, with populations at both high
elevations in the alpine zone and in canyons of the Eastern Sierra Nevada
at lower elevation. The closely related
Limestone Salamander (Hydromantes brunus) is endemic to the Merced River
valley of Mariposa Co., CA. Populations
of H. platycephalus in the high Sierra Nevada experience much colder temperatures
throughout the year than those in
the Eastern Sierra Nevada, and might therefore be expected to have evolved
increased physiological tolerance for
cold. By contrast, populations in the Eastern Sierra Nevada, especially
those at lower elevations in the Owens Valley,
are exposed to warmer temperatures and would be expected to show an elevated
tolerance for higher temperatures. I
measured critical thermal minimum (CTmin) and maximum (CTmax) at two acclimation
temperatures (4° and 15°C)
for H. platycephalus from the northern and southern high Sierra Nevada,
the Owens Valley and H. brunus.
Surprisingly, none of the populations of H. platycephalus differed in
their thermal tolerances, despite experiencing
markedly different thermal environments in nature. Hydromantes brunus,
however, had a significantly lower CTmax
than all populations of H. platycephalus, despite living at much lower
elevation than H. platycephalus. While some
populations of salamanders differed significantly in their CTmin and CTmax
depending on acclimation temperature, others showed little acclimation
response. These results will contribute to a better understanding of the
climatic niche and tolerances of Hydromantes in California, which will
help to identify areas and populations at risk from rising global temperatures.