Conference Abstracts and Presentations

* invited presentation


Talk*
CLIMATE CHANGE AND SPRING-FED WETLANDS: MONITORING CHALLENGES AND ANTICIPATED CONSEQUENCES OF DECREASING RECHARGE

SADA, DONALD W. (1); HERBST, DAVID B. (2)
(1) Desert Research Institute, Reno, NV 89509, (2) Sierra Nevada Aquatic Research Laboratory, Mammoth Lakes, CA
93546

Springs occur where groundwater reaches the surface through natural processes. Thousands are scattered across the
west in all elevations, geological settings, and landscape settings. Their environments are highly variable across the
landscape and each spring is distinctive because of many interacting factors such as discharge, water chemistry,
elevation, aspect, water temperature, persistence, and substrate. These characteristics are a function of geology,
climate, and aquifer provinence, transmissivity, and size. In arid lands most springs are isolated and intermittent, and
most large springs lie on bajadas and valley floors.

Predictive models describing species composition of benthic and riparian communities are problematic because of
isolation, colonization/extinction dynamics, and environmental distinctiveness of each spring, but work in southern
Nevada and California shows that species richness in aquatic and riparian communities is correlated with discharge,
communities change from environmentally sensitive and intolerant to tolerant along a gradient from source to
terminus, and crenobiontics occur only in geologically persistent springs. Community structure is at the same time
influenced by human and natural factors (e.g., diversion, livestock, drought, floods).

Springs provide an excellent opportunity to track climate change because their discharge responds to precipitation,
and they are small and their physical attributes, chemistry, and biota are easy to sample and monitor. Change can be
tracked at all springs, but natural background variability can be more accurately and easily documented at persistent
springs that are unaffected by human disturbance (reference condition springs). These springs are supported by
aquifers with moderate residence time, support relatively diverse aquatic and riparian communities, and often
inhabited by obligate crenobiontic organisms. Springs that dry frequently are poor monitoring candidates because
decades are required to determine drying periodicity, and they typically have a depauperate fauna consisting of
common opportunistic species. Springs supported by regional aquifers are also poor monitoring candidates because
sources are deep ancient waters with relatively, constant discharge rates, and do not track contemporary changes in
climate.

Decreased precipitation is anticipated to reduce discharge, which will alter thermal regimes and reduce spring brook
length, aquatic habitat heterogeneity, and soil moisture. Extent of the stable environment associated with spring
sources will decrease and the amount of variable environment associated with downstream reaches will increase.
Aquatic communities near spring sources will change most from being dominated by crenobiontic macroinvertebrates
to dominance by tolerant forms such as midges and pulmonate mollusks. In the riparian zone, the extent and cover by
obligatory wetland vegetation will decrease, and facultative and upland vegetation will increase.

 

Talk
PERIGLACIAL ACTIVITY ALONG AN ELEVATIONAL GRADIENT OF GLORIA SITES, WHITE MOUNTAINS, CALIFORNIA

SCHMID, GINGER L.; WILKERSON, FORREST D.
Department of Geography, Minnesota State University, Mankato MN, 56001

This presentation summarizes three to sixteen years of periglacial data collection in the White Mountains of California
at or near GLORIA sites. In lower elevation GLORIA sites, measurements of surface activity have been conducted since
2005 with three years of results. In upper elevation GLORIA sites, measurements of periglacial activity have been
conducted since 1991. Rates of surface activity vary along an elevational transect running from Sage Hen Flat (3265 m)
to just below the summit of White Mountain Peak (4180 m). Activity at Sage Hen Flat is minimal, primarily due to
needle ice growth, and is restricted to the surface. Activity rates increase as elevation increases, with the Mount
Barcroft site showing signs of deeper frost penetration and vertical movement in small-scale frost boils approaching 8
cm per year. Larger periglacial sorted polygons at Mount Barcroft are relict and have shown no signs of activity since
1991. The highest elevation sites near the summit of White Mountain Peak continue to show signs of deep-seated
activity and the summit cone may be underlain by permafrost. All landforms near the summit, including the largescale
sorted nets, show signs of horizontal and vertical movement that in some cases approach 10 cm per year.
Although periglacial activity appears to be slowing at all sites below 4000 m, the lack of long-term data at the lowest
sites precludes a definite link between decreasing activity and climate change at this time.

 

Talk
POPULATION GENETICS, DISTRIBUTIONAL MODELING AND CLIMATE CHANGE IN SIERRA NEVADA ALPINE
BUTTERFLIES

SCHOVILLE, SEAN D.
University of California, Berkeley, Environmental Science, Policy and Management, 137 Mulford Hall #3114, Berkeley,
CA 94720-3114

Rapid changes in ecological conditions have occurred over the past 15,000 years at high elevations in the California
Sierra Nevada. First, the recession and disappearance of alpine glaciers from elevations above 9,500 feet caused
significant restructuring of alpine communities and impacted the genetic variation of alpine-adapted organisms.
Second, warming trends and land-use impacts over the last century have threatened populations of alpine species
even in areas managed as National Forests and National Parks. My research examines patterns of genetic diversity in
codistributed alpine butterflies to examine the history and structure of populations in the Sierra Nevada. Alpine
butterflies have genetic patterns consistent with single geographic origins and recent population expansion across high
elevations in the Sierra Nevada. To highlight priority areas for management and conservation under climate change, I
develop species distribution models based on environmental data and butterfly occurrence data. Finally, I examine
how climate records over the last century suggest that declines in alpine species are likely to have occurred
predominantly in the northern Sierra Nevada.

 

Talk*
EXAMINING POTENTIAL IMPLICATIONS OF GLOBAL CLIMATE CHANGE AND MIGRATORY BIRD MOVEMENT ON THE SPREAD OF TWO ZOONOTIC DISEASES - WEST NILE VIRUS AND H5N1 HIGHLY PATHOGENIC AVIAN INFLUENZA

SCHWARZBACH, STEVEN
Western Ecological Research Center, USGS, 3020 University Drive, Suite 3006, Sacramento, CA 95819

The North American strain of the West Nile Virus (WNV) and the highly pathogenic H5N1 strain of Avian Influenza are
both recently emerged diseases of birds that claim not only birds but humans and other mammals as victims. Each
disease has a unique but distinct seasonal pattern that suggests both weather and bird migrations are important
factors affecting geographic distribution. The Culex mosquito which thrives in drought conditions is the principal
mosquito host and vector for WNV. WNV first appeared in the western hemisphere in 1999 in New York City. In 2004
and 2005 it was responsible for mortality events in Sage Grouse on the east side of the Sierra. Changes in climate and
weather which affect the distribution of Culex mosquitos or amplifying host birds more resistant to WNV could
theoretically affect the distribution and occurrence of WNV. The H5N1 HPAI virus is largely a disease of poultry that
originated in the rice growing regions of China. The disease has spilled over into wild birds and in rare cases infected
humans. Qinghai Lake, China, in May 2005 was the site of the first massive wild bird die-offs due to H5N1 HPAI that
demonstrably did not involve poultry. Nearly 3300 Bar-headed geese, a species of the Tibetan plateau and a trans-
Himalayan migrant not associated with rice, died in this wild bird outbreak. Genetic evidence and the temporal
sequence of the infection among different waterbird species at Qinghai suggested BHGOs were the initial vector, or
alternatively perhaps, only the initial victim. The genotype virus identified at Qinghai in the May 2005 die-off
subsequently spread to wild birds in Europe then Africa in the fall of 2005. The initial spread to Europe was thought
to be exacerbated by unusually cold weather that pushed migratory birds along the Baltic flyway in a south- south
west direction earlier than normal. The role of wild migratory birds in the transmission of the virus is still not fully
understood and is a subject of ongoing research by USGS and many others. The future spread of HPAI has been the
subject of much speculation and has inspired a national surveillance program in the United States and Canada where it
still remains undetected. The role of changing climate in the future spread of HPAI is unknown but most likely will be
related to effects of climate upon patterns and timing of avian migration.

 

Talk*
BIRD CONSERVATION, RESOURCE MANAGEMENT, AND CLIMATE CHANGE

SEAVY, NATHANIEL (1,2); GEUPEL, GEOFFREY (1); HERZOG, MARK (1); MOSS, STELLA (1); STRALBERG, DIANA (1)
(1) PRBO Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954, (2) Information Center for the
Environment, University of California, Davis, CA 95616

The conservation of wildlife populations and their habitat is one component of natural resource management. PRBO
Conservation Science has worked in the Eastern Sierra to use avian science to inform the management and restoration
of bird habitats. Today, climate change has the potential to make fundamental changes to the many aspects of the
ways we manage natural resources. As part of a new initiative, PRBO is working at the interface of resource
management, climate change, and bird conservation. In the past, we have used suites of bird species to serve as
indicators of successful management. Today, we are working to understand whether or not these species will still
persist as the climate changes. In the past, we investigated riparian restoration to evaluate our ability to return bird
populations to their historical condition. Today, riparian restoration is important because it provides connectivity and
thermal refugia that will help make ecosystems resilient to climate change. In the past, we monitored bird
populations to understand local changes in habitat conditions. Today, we monitor bird populations to understand
global changes in climatic conditions. Our preliminary results suggest that climate change will pose major challenges
to our historical approach to resource management and bird conservation.

 

Talk*
CLIMATE CHANGE AND HIGH ELEVATION AMPHIBIANS AND REPTILES IN THE SIERRA NEVADA

SENDAK, CARRIE M.; MATTHEWS, KATHLEEN R.
USDA Forest Service, PSW Research Station, Albany, CA 94701

Climate change is predicted to impact high elevation aquatic habitats by decreasing the amount of precipitation
falling as snowpack, the timing of snowmelt, and increasing air and water temperatures. These predicted changes
will likely have dramatic effects on the amphibians and reptiles in the eastern Sierra Nevada, however species will
respond differently due to their specific habitat requirements and life histories. Amphibian and reptile populations in
the Sierra Nevada are especially vulnerable to climate change impacts because their populations have already
declined, and are subject to other stressors such as disease, pollutants, and exotic trout. Amphibians and reptiles are
ectothermic and therefore sensitive to changes in temperature and water availability, and their different life history
stages (eggs, tadpoles, and adults) have different requirements for water and temperature. Current research in Kings
Canyon National Park documented significant declines in Sierra Nevada yellow-legged frog recruitment in low
snowpack years; lower snowpack is predicted to increase under climate change scenarios. All life history stages (eggs,
tadpoles, and adults) of Sierra Nevada Yellow-legged Frogs are closely tied to aquatic habitats and may be most
vulnerable to changes in water availability. Moreover, their tadpoles require 3-4 years of permanent water for
metamorphosis, so tadpoles die if lakes dry. Other common eastern Sierra amphibians including adult treefrogs and
Yosemite toads typically only visit aquatic habitats during breeding and then move to more terrestrial, upland
habitats, so they may be less affected by changes in water availability. The distribution and abundance of high
elevation mountain garter snakes are affected by amphibian populations so garter snakes will decline if amphibians
are adversely impacted by climate change. In addition to understanding the impacts of climate change on amphibians
and reptiles, it will be crucial to determine the interaction with other stressors—exotic species, pollutants, disease,
etc.

 

Talk
DO C3 AND C4 PLANTS RESPOND THE SAME WAY TO CLIMATE CHANGE? INSIGHTS FROM COMPARATIVE STUDIES WITH THE C4 GRASS Muhlenbergia richardsonis AT HIGH ELEVATIONS IN CALIFORNIA'S WHITE MOUNTAINS

SKILLMAN, JOHN B (1); SAGE, ROWAN F (2); MEYER, ARCHIE (1)
(1) Department of Biology, California State University, San Bernardino, Ca 92407, USA. (2) Department of Ecology and
Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada

Climate change-mediated altitudinal shifts in the distribution of many montane C3 species are well documented.
Comparable changes for C4 species remain unreported. Ecophysiological theory predicts performance tradeoffs
between C3 and C4 plants will depend upon both partial pressures of atmospheric CO2 and daytime air temperatures.
C4 plants should be favored under low CO2 and/or at warmer temperatures while the opposite conditions should favor
C3 plants. CO2 and temperature decline with elevation and, at present, most C4 species are restricted to lower
elevations in all major cordilleras. Thus, temperature currently plays a predominant role in shaping the
photosynthetic makeup of plant communities along elevation gradients. But increasing CO2 and temperature due to
climate change may alter the relative performance and/or altitudinal limits of C4 plants in montane ecosystems. The
grass Muhlenbergia richardsonis holds the high elevation record for any C4 species in North America, reaching nearly
4000 meters in California's White Mountains. We have examined regional climate and herbarium records for
M. richardsonis and co-occurring C3 grass species to see if there is evidence for differential elevation shifts
between C4 and C3 species plausibly attributable to recent climate change. We have also conducted surveys on leaf
stomatal density, nitrogen concentration, and carbon isotope composition on M. richardsonis and cooccurring
C3 grass species along a 3000-3800 meter elevation gradient in the White Mountains. These foliar traits can
provide insight into how elevation-dependent co-variation in CO2 and temperature affect plant carbon gain limitations
and whether this differs between C4 and C3 species. Our findings provide limited evidence that M.
richardsonis
has recently moved upslope while reference C3 species have not. Foliar trait data are consistent with the
hypothesis that C4 plants are photosynthetically pre-adapted to the CO2-poor atmospheres of warming Alpine habitats.
C4 species may become frequent in future Alpine plant communities.

 

Talk
CHANGES IN PLANT COMMUNITIES AND ECOPHYSIOLOGY ALONG ELEVATION GRADIENTS IN INYO COUNTY: BIOPHYSICAL RESPONSES TO INCREASED TEMPERATURE

SLATON, MICHÈLE R.
National Park Service, Death Valley National Park, Death Valley, CA 92328

Inyo County contains at least 12 isolated mountain ranges with 6000 ft. or more relief, which offer an ideal setting for
replicated studies of vegetation patterns along elevation gradients, and potential shifts with climate change. Largescale,
30-year record climatic grids were created for this study area, and summarized for map units of individual
vegetation communities, ranging from creosote shrublands below sea level, to mixed desert shrublands and sagebrush
steppe, forested lands, and alpine communities at over 14,000 ft. Estimates for changes in available land area for
these communities under predicted temperature regimes are given, and generally indicate reductions in area for
communities at higher elevation, but expansion for some communities at low elevations. Geomorphologic and
substrate constraints significantly reduce land availability for many communities, such as specialized shrublands and
herbaceous vegetation types. Biophysical changes in temperature, pressure, and solar radiation with elevation result
in disproportionately greater increases in temperature and water loss for communities at higher elevations under
predicted climate regimes, and may result in accelerated changes in those areas.

 

Talk*
CLIMATE-INDUCED ELEVATION SHIFTS IN A SIERRA NEVADA FOOD WEB: HOW DO THE PREDATORS RESPOND?

SMILEY, JOHN
University of California White Mountain Research Station, 3000 E. Line St., Bishop CA 93514

During the past few decades, climate in the Sierra Nevada Mountains of California has warmed enough to produce earlier snowmelt and a longer growing season at subalpine and alpine elevations. A long-term study of the willow leaf beetle Chrysomela aeneicollis (Coleoptera: Chrysomelidae) has revealed a marked upward shift in elevational range, such that local populations at lower elevations have gone extinct while new populations have been established at high elevations. The overall average upward shift is on the order of 300m (1000’). Approximately 1/3 of summer mortality on the beetles can be attributed to the hunting wasp Symmorphus cristatus (Hymenoptera: Vespidae). This wasp feeds its young exclusively by provisioning its nest with 3rd instar larvae of the willow leaf beetle. Wasp nesting behavior was observed between 1998 and 2008 at two sites: a 2925m site where willow leaf beetles became locally extinct in 2004, and a 3230m site where the leaf beetles maintained healthy populations throughout the study. Between 1982 and 1999, wasps were absent from the 3230m site, but in 2000 began gradually increasing their numbers, becoming common by 2004. Mean hunting time, a measure of how long it takes to find leaf beetle prey, was found to be inversely related to prey abundance, and became longer and longer as the prey became locally extinct at the 2925m site. By 2006, wasps had abandoned the 2925m site completely. By contrast, mean hunting time at the 3230m site was short (~15 minutes) during and after 2004. By 2007 the upward shift appeared to be complete, with hunting times and other parameters at 3230m being approximately what they were at 2925m in 1998. The predator, like its prey, experienced an average upward shift of about 300m.

 

Talk*
MONO LAKE, RESTORATION, AND CHANGING CLIMATE

SPIVY-WEBER, FRANCES
California State Water Resources Control Board, Redondo Beach, CA

State Perspective on Changing Climate Issues that affect Mono Lake and Mono Basin Restoration: The State Air
Resources Board will complete its scoping plan for reducing ghg emissions at the end of 2008, which will be followed
by 1-2 years of implementation actions, both incentives and regulations. At the same time the State is ramping up its
work on adaptation to climate change with a California EPA report to the governor and legislature in late 2008. All
State agencies are engaged in both processes, and those that work closely with Mono Lake--State Water Board, Fish
and Game, State Lands, Air Board--can consider incorporating research and restoration programs at the Lake and in
the region into California response to climate change.

 

Talk*
ALPINE MEADOWS, SIERRA NEVADA BIGHORN SHEEP, AND WILDERNESS: WILL CLIMATE CHANGE IMPACT RECOVERY?

STEPHENSON, THOMAS R. (1,2); GREENE, LACEY (1,2); KONDE, LORA (1)
(1) California Department of Fish and Game, 407 West Line St., Bishop, CA 93514, (2) University of Montana,
Missoula, MT

Sierra Nevada bighorn sheep are a federally endangered species that spends most, and in some cases all, of the year
in the alpine. Sierra bighorn are dependent upon, and well adapted to, a landscape above 11,000 feet during both
summer and winter. Vegetation that provides forage for bighorn is limited in the alpine of the Sierra Nevada. The
seasonally arid climate characteristic of this range results in minimal precipitation during the growing season.
Although of limited distribution in the alpine of the Sierra, meadows provide an important source of forage biomass
and nutrients for bighorn sheep. Many of these alpine meadows are fed by permanent snow fields that are in decline
as a result of a warming climate. Advances in tree-line also may result in the eventual loss of alpine habitat.
Consequently, some alpine meadows are at risk of disappearing or at least drying and senescing earlier in the growing
season. If meadow systems disappear in the alpine, the ability of the Sierra Nevada to support bighorn sheep will
decline and recovery may be hampered. We used logistic regression and resource selection functions to quantify use
of alpine meadows by bighorn sheep in the Sierra Nevada. We examined the use of these meadows on a monthly basis
and among herd units. Sierra Nevada bighorn sheep are an umbrella species that represents the health and landscape
integrity of the Sierra Nevada; they are dependent upon a contiguous, expansive wilderness landscape. In addition to
the necessity of alpine habitats, bighorn sheep populations are most productive when they use lower elevation (<8,000
feet) winter ranges. In some regions of the Sierra Nevada, forest cover reduces the potential for bighorn to use lower
elevation ranges. Prescribed burning is proposed to remove forest cover and create the open habitats preferred by
bighorn sheep. Such management actions will increase the likelihood of recovery of this endangered animal. Yet in
some areas, prescribed burns need to occur within wilderness.

 

Plenary Talk*
ADAPTIVE MANAGEMENT; OPPORTUNITIES AND CHALLENGES IN MANAGING ECOSYSTEMS UNDER CHANGING CLIMATES

STINE, PETER A.
USDA Forest Service, Sierra Nevada Research Center, 1731 Research Park Dr., Davis, CA 95618

Climate Change presents significant challenges to all sectors of our society. In a landscape of dire predictions and
with a partially skeptical public there is a need to offer options that give us direction for a constructive future. The
scientific community needs to come forward with solutions amongst the throng of discouraging problems that are
being reported. In the land management arena there are clear roles for the professional manager and researcher to
take in making a contribution. There are both adaptation and mitigation options that are worthy of exploration.
Given the uncertain future these options need to be explored in an active adaptive management approach in a
partnership between research and management. Examples of the new partnership in the Southern
Sierra will be discussed.

 

Talk*
TIMING AND MAGNITUDE OF LATE PLEISTOCENE AND HOLOCENE GLACIATIONS IN YOSEMITE NATIONAL PARK

STOCK, GREG M. (1); DÜHNFORTH, MIRIAM (2); ANDERSON, ROBERT (2); KESSLER, MARK (2); DEVINE, PETE (3)
(1) Division of Resources Management and Science, Yosemite National Park, El Portal, CA 95318 (2) Institute of Arctic
and Alpine Research, University of Colorado, Boulder, CO 80309. (3) Yosemite Association, El Portal, CA 95318

We mapped the extent of the Tioga (Last Glacial Maximum) glaciation in Yosemite National Park using a combination
of field mapping, LiDAR data acquistion, geochronology, and numerical modeling. Results tend to confirm previous
mapping by Matthes (1930) and Wahrhaftig (unpublished), with slight adjustments in the Tuolumne drainage. U/Pb
dating of granitic boulders along the rim of Yosemite Valley confirms the presence of an early (Sherwin?) valley-filling
glaciation. Boulders on Tahoe moraines yield cosmogenic beryllium-10 exposure ages of >100 kyr. Boulders on Tioga
terminal moraines in Yosemite Valley yield exposure ages of ~22 kyr, and boulders on lateral moraines in the Merced
and Tuolumne canyons yield exposure ages of 19-21 kyr. Exposure ages of polished bedrock surfaces suggest that the
Tioga deglaciation began ~19 ka and was complete by ~10 ka. At present there are no confirmed glacial deposits of
Younger Dryas age in Yosemite National Park.

Matthes (Little Ice Age) glaciers in Yosemite National Park have retreated substantially since their maximum extent
circa 750 yrs. B.P. This retreat has important implications for river-dependent ecosystems downstream. We are
monitoring the retreat of the Lyell and Maclure glaciers by reoccupying photo points established as early as 1880,
resurveying cross-glacier transects established in the 1930’s, and mapping the glacier terminus with GPS. Recently
acquired LiDAR data allows for more accurate volume calculations in the future. Future work will include field and
numerical assessments of glacier mass balance and predictions of future water yield in light of projected warming.

 

Plenary Talk*
INDICATIONS FOR PRESENT AND FUTURE MANAGEMENT FROM PAST GREAT BASIN CLIMATE AND VEGETATION CHANGE

TAUSCH, ROBIN J.
USDA Forest Service, Rocky Mountain Research Station, Reno, NV 89503

Arid and semi-arid ecosystems of the Great Basin have recently seen major changes in response to climate and other
human driven environmental changes that represent important management challenges. From both vegetation data,
and other proxy data, centennial scale climate oscillations have occurred across the Holocene, and similar changes are
possible in the future. Sensitivity of Great Basin vegetation to these past climate changes has been consistent over
the Holocene, particularly in response to drought. The associated changes resulting from the repeated drought cycles
in particular, have provided important information on the kinds of vegetation changes that are possible in the Great
Basin in response to significant changes in climate. It is the understanding of the relationships between these
Holocene climate changes and the associated vegetation changes that can help management to anticipate future
vegetation changes. The patterns and rates of change in Great Basin piñon-juniper woodlands over the last 150 years
provides an example of the speed and landscape scales at which climate, and human driven changes in environmental
conditions, can drive landscape scale ecosystem changes. The major challenge for management is that, combined
with the increasing presence of exotics, these climate and environmentally driven changes can result in permanent
alteration of the affected ecosystems.

 

Talk*
INTEGRATED MANAGEMENT FOR CLIMATE IN THE EASTERN SIERRA NEVADA

UPCHURCH, JIM
USDA Forest Service, Inyo National Forest, Bishop, CA

no abstract submitted

 

Talk*
WILDERNESS LAW AND POLICY IN A TIME OF CLIMATE CHANGE

VAIL, JEFFREY
USDA Forest Service, Wilderness and Wild and Scenic Rivers, Pacific Southwest Region, Vallejo, CA

I will present an overview of Wilderness law and policy, particularly describing the definition and purposes of
wilderness. Relying upon the definition and purposes for which wilderness areas are to be administered, I will discuss
how wilderness may be particularly well-suited to assess the consequences of climate change on our natural resources
and the options and limitations to mitigating effects of climate change in wilderness. I will discuss briefly how
determinations of wilderness character and maintenance of wilderness in its untrammeled, natural condition may be
impacted by a changing climate. Finally, I will offer two alternative scenarios for management response to the impact
of climate change on wilderness to encourage reflection regarding the appropriate stewardship approach to changing
wilderness conditions resulting substantially from human activities occurring outside of wilderness areas.

 

Talk*
A RANGE-WIDE MODEL OF NIGHT-TIME TEMPERATURE INVERSION BASED ON HOURLY TEMPERATURE DATA

VAN DE VEN, CHRISTOPHER (1); WEISS, STUART B. (2); ERNST, GARY (3)
(1) Albion College, Albion, MI, (2) Creekside Center for Earth Observation, Menlo Park, CA 94025, (3) Stanford
University, Stanford CA 94035

Plants respond to a warming climate by shifting their distributions to cooler areas. Typically, this results in an
upslope migration, but it can also result in shifts across aspects (such as from south- to north-facing slopes).
However, in the case of many mountain-slope valleys, plants have responded by moving downslope toward valley
floors. We suggest that they are responded to less severe night-time cold air drainage into those valleys. To
understand the magnitude, timing, and pattern of the cold air drainage, we have deployed temperature data loggers
throughout the Crooked Creek valley and selected surrounding regions within the White Mountains, CA. From late July
to early October, 35 thermochrons recorded hourly temperature in 2006, 70 were deployed in 2007, and 98 deployed
in 2008. Although the 2008 data have not been analyzed yet, the previous data showed significant night-time
temperature inversions, frequently with valley floors 7°C cooler than adjacent ridge tops, a few hundred meters
higher in elevation.

Using the 2006 temperature data, a 10m digital elevation model (DEM), and data from long-term weather stations, we
modeled the night-time minimum temperatures across the range. Using multiple least-squares regression, deviations
from the local weathers station were predicted for the Crooked Creek valley using topographic position (the local
elevation minus the average elevation within a 500m radius), slope, and the absolute value of topographic position
(r2=0.92). Using the same variables embedded with the overall lapse rate, these results were extrapolated across the
rest of the White Mountains, showing similar patterns and magnitudes of night-time temperature inversions. As
regional temperatures increase, the cold air draining down these valleys also are become less cold, allowing
bristlecone pine (Pinus longaeva) and limber pine (P. flexilis) to become established downslope, closer to the valley
floors, a pattern that has been observed in the field and in airphoto analyses.

 

Talk*
IMPROVING MEADOW HEALTH IN THE FACE OF CLIMATE CHANGE

Meadows in the Sierra Nevada are particularly at risk of the impacts associated with climate change as they have
experienced significant degradation in the past 150 years. In this presentation, I will summarize the historical impacts
to meadow health such as grazing, invasive species, and shrub encroachment. After reviewing the condition of Sierra
meadows and meadow residents, the current efforts to improve meadow health in the Sierra
will be discussed. Finally, I will address the challenges to improving or buffering Sierra meadows to adapt to climate
change.

 

Talk*
CLIMATE CHANGE AND THE MONO LAKE WATER BALANCE: IMPLICATIONS FOR IMPLEMENTING THE MONO LAKE WATER RIGHTS DECISIONS

VORSTER, PETER (1); REIS, GREGORY (2)
(1) Consulting Hydrologist, Oakland, CA, (2) Mono Lake Committee, Lee Vining, CA

State Water Resources Control Board Decision 1631 and Orders 98-05 and 98-07 used the historic hydro-climatology of
the mid to late 20th century in a deterministic water balance based forecast model to determine future lake levels and
allocate in-stream flows and exports. Similarly the Los Angeles Department of Water and Power (DWP) relies on
historic hydrology to guide operations and the implementation of these decisions. We examine the climate change
impact on lake evaporation and stream runoff and the near and long-term management challenges that it poses. Even
with no change in average precipitation and runoff, increasing temperatures and greater evaporation rates translate
into a longer transition period at the current reduced export levels while the lake rises to the trigger level of 6391 ft
and less exports on average as the lake fluctuates around that level. The current lake level is lower than what the
models forecasted and it will take an abnormally wet period to achieve the 6391 ft level by 2014- the year that the
State Board will determine if any revisions to its decisions are warranted if that level has not been achieved. Further
analysis will indicate how much of the discrepancy is due to model error and how much is due to climate change.
Likewise higher temperatures during the winter and spring change the timing and possibly the magnitude of peak
snowmelt runoff. Already earlier than expected snowmelt peaks have created operational challenges for DWP in its
management of peak flows on Lee Vining Creek. Modification of the post-snowmelt season hydrograph may be needed
for other ecosystem management needs such as riparian recruitment and stream temperatures.

 

Talk*
CLIMATE CHANGE AND DESERT BIGHORN SHEEP: THE DEVIL IS IN THE DETAILS

WEHAUSEN, JOHN D (1); CLINTON W. EPPS (2)
(1) White Mountain Research Station, 3000 E. Line St., Bishop, CA 93514, (2) Oregon State University,
Department of Fisheries and Wildlife, Corvallis, OR 97331-4501

Projecting the effects of climate change on wildlife species requires a detailed understanding of ecological
causal networks that link precise climatic variables with key demographic parameters that drive population
dynamics. Desert bighorn sheep in California are a model species to examine this question because longterm
data bases needed to make such analyses exist. Deserts are water limited ecosystems. For bighorn
sheep populations in the Mojave Desert of California, population dynamics substantially reflect the
influence of late winter and spring nutrient intake on lamb survival. Variation in that nutrient intake is
driven by the amount of rainfall in the cold season (October-April). Within that season, rainfall in certain
months is most influential, with different periods acting independently through influences on different
forage classes (annual vs. perennial plants). The influence of temperature on diet quality also varies with
month. Early in the cold season warmer temperatures improve nutrient intake for bighorn sheep by
accelerating the production of new forage growth when it is temperature limited. In contrast, later in the
growing season the opposite is true because warmer temperatures hasten the end of the growing season by
accelerating the loss of soil moisture. A key implication of these details relative to climate change is the
need for regional projections of this change to have adequate precision. For the Mojave Desert, climate
projection models agree that temperatures will rise, but disagree on how much. They also disagree on
whether rainfall will increase or decrease. In short, those models are inadequate of allow a meaningful
prediction of potential effects on bighorn sheep populations. Long term climatic data will be examined
instead for trends in key variables.

 

Talk*
UP, DOWN, AND SIDEWAYS: COMPLEX RESPONSES OF PLANT SPECIES TO CLIMATE CHANGE IN THE WHITE MOUNTAINS

WEISS, STUART B. (1); VAN DE VEN, CHRISTOPHER (2); ERNST, GARY (3)
(1) Creekside Center for Earth Observation, Menlo Park, CA 94025 (2) Albion College, Albion, MI, (3) Stanford
University, Stanford CA 94035

The migration of montane plant populations in response to climate changes is mediated by complex topography and
geologic substrate. Complex environmental gradients in the White Mountains in eastern California produce striking
variation in vegetation composition over short distances, dominated by the effects of elevation on temperature and
precipitation, but more locally modified by gradients in potential insolation, slope, topographic position, and diverse
geologic substrates including carbonate, metaclastic, and granitic rocks. We built and validated predictive models of
plant species distributions at a scale of 50 m using multivariate statistics, and predicted future distributions by
assuming that warming trends correspond to changes in effective elevation (3ºC = 500 m). The ascent of species into
diminishing areas at higher elevations creates the “mountaintop squeeze” scenario, and several high alpine plants
appear vulnerable to being forced off the highest mountain peak (4340 m) with moderate warming (3ºC). Geologic
substrate constrains species as well, so dolomite specialists cannot advance to the highest elevations that are
dominated by granitic rocks.

This scenario is complicated by the complex reality of topoclimatic variation in the White Mountains. Sharp gradients
in minimum temperatures occur with cold-air drainage into valleys, and downward movements of pine populations
have been documented. Maximum temperature gradients exist across changes in aspect, so species may migrate
laterally across canyons and ridges from south- to north-facing slopes. Differing migration rates will lead to new plant
assemblages – at their upper elevation limit, pinyon pines are advancing into limber-bristlecone forests. The
migration of species such as nitrogen fixing mountain mahogany and soil-forming dwarf sagebrush, may greatly affect
soil properties. These complexities require detailed field mapping of species distributions and demography at range
limits, coupled with direct measurements of temperatures, to detect varied responses to climate change.

 

Plenary Talk*
STRATEGIC APPROACHES OF THE NATIONAL PARK SERVICE FOR ADAPTING TO CLIMATE CHANGE

WELLING, LEIGH
USDI Park Service, 1201 Oakridge Drive, Fort Collins, CO 80525

Ecosystems and species will change as climate changes, forcing managers to consider new strategies for resource
protection. What are the best strategies to adopt in the face of unprecedented and highly consequential changes that
cannot be accurately predicted or controlled? A number of activities have been initiated over the last couple of years
to help prepare and guide National Park Service managers in coping with climate change. However, much work
remains if parks are to develop and implement an effective strategy for moving forward on this issue. Examples of
some current approaches and actions will be given, including policy, planning, mitigation, adaptation, and
communication efforts. These will be used to foster discussion and gain feedback on the challenges and opportunities
climate change presents for natural and cultural resources management.

 

Talk*
EFFECTS OF WATER AVAILABILITY ON ALPINE TUNDRA SEEDLING GERMINATION AND ESTABLISHMENT IN THE SIERRA NEVADA

WENK, ELIZABETH; DAWSON, TODD
Department of Integrative Biology, 3060 Valley Life Sciences Building, University of California, Berkeley, CA 94720-
3140

In a community of alpine tundra plants from the Sierra Nevada, some species are widespread, occurring across all four
substrates studied: diorite, granite, hornfels, and marble. Other species are restricted to fewer soil types. We
collected seeds from 12 species and performed a reciprocal transplant experiment in growth chambers using native
soils. Eleven species germinated and established equally well across all soil types, indicating substrate chemistry did
not alone determine species field distributions. However, two patterns emerged that may contribute to our
understanding of species composition and dominance across substrates. First, species more dominant on the drier
substrates reached at least half their total germination within two weeks of planting. Species more dominant on the
wetter substrates required a longer period in wet soil to germinate. Second, there is a strong correlation between
species relative abundance and percent germination, indicating that high percent germination may contribute to some
species’ dominance. In the field, germinants were only observed during an unusually wet summer, indicating
germination is a rare and water-limited event. If growing season rainfall decreases in the Sierra Nevada, less
germination is expected and species requiring long periods of wet soil are expected to be disproportionately affected.