Terrestrial Botany
Tree-Ring Reconstruction of Decadal-Scale Climate VariabilityFranco Biondi, Geosciences Research Division, Scripps Institution of Oceanography, UC San Diego
This project aims at quantifying climate change during the past few centuries over western North America. Valentine Camp was chosen as one of the field collection sites due to its population of Jeffrey Pine (Pinus jeffreyi). Samples were collected from 14 live trees and 3 dead ones. The diameters of cored pines ranged between 100 and 175 cm, with a mean of 130 cm and a standard deviation of 21 cm. A total of 32 ring-width series from 15 trees were cross-dated, measured, and combined into a 470-year tree-ring chronology, from 1527 to 1996. This chronology has been included in the network that we are developing to achieve our research objectives. Funding: National Science Foundation.
Population Ecology, Ecophysiology, and Genetics of Mountain Brome GrassLaurie Luedtke, Agronomy and Range Science, UC Davis
This research attempts to distinguish the genetic and environmental components of growth and reproductive variation in a common grass found in different habitats in the western United States. Bromus marginatus, Mountain Brome Grass, has been transplanted from a variety of sites to Valentine Camp. By growing the same species from different environments together, I can determine if particular genotypes have higher growth rates or greater reproductive output, or whether the environment controls these resource variables. Funding: Self-funded.
Pollination in PenstamonPaul Wilson, Department of Biology, California State University at Northridge
We conducted preliminary testing of Pollen Presentation Theory (PPT), a theory that predicts how natural selection shapes the pollen-bearing anthers of flowers. PPT predicts that when pollinators visits are frequent and effective, plants that restrict pollen availability to individual pollinators will donate more pollen to other plants than those that allow visitors free access. When pollinators are scarce or ineffective, plants will be more successful as males if they present their pollen simultaneously. We tested two species of Penstamon, one allegedly bee pollinated, the other hummingbird pollinated. By contrasting the two species we are testing the hypotheses that (a) gradual pollen presentation is associated with frequent and effective pollinator visitation, (b) high nectar secretion is correlated with frequent visitation, and (c) gradual pollen presentation is secondarily correlated with high nectar secretion. Funding: Research and Sponsored Projects, California State University at Northridge.Terrestrial ZoologyMicroclimate and Plant Distribution for a Mojave Desert - Great Basin Transition Zone: Classical and Molecular-Based Monographic Revision of the CephalobinaSteven A. Nadler, Department of Nematology, UC Davis
James G. Baldwin, Department of Nematology, UC Riverside
One undescribed species of nematode (Panagrolaimus sp.) was isolated from the bark of Pinus murrayana at Valentine Eastern Sierra Reserve. This nematode taxon has been established in vitro (SAN-015), and is maintained on agar plates. Based on a preliminary examination and comparison of diagnostic structures, this isolate is likely a new species. A region of the nuclear large-subunit rRNA (D2/D3 regions) has been sequenced for this taxon to facilitate comparison to other congeners. As additional Panagrolaimus species are obtained, phylogenetic analysis based on nucleotide sequences will be performed. The new species will be formally described during the course of the project. Funding: National Science Foundation, PEET Program.
Effects of Ultraviolet-B Radiation on DNA Damage, DNA Repair, and Hatching Success in Bufo canorus, Rana muscosa, and Hyla regilla in Yosemite National ParkWalter J. Sadinski, Radiobiology and Environmental Health, UC San Francisco
Our current work in Yosemite National Park is designed to determine whether reduced reproductive success might be causing reported declines in the abundances and distributions of populations of Yosemite toads (Bufo canorus), mountain yellow-legged frogs (Rana muscosa), and to a lesser extent, Pacific treefrogs (Hyla regilla). Locating breeding sites, assessing hatching success and survival to metamorphosis at breeding sites, and conducting experimental tests of potential factors that might be causing any reductions in reproductive success are included in this work. A major focus thus far has been to study whether ambient levels of ultraviolet-B radiation have caused any reductions in hatching success or have induced DNA damage among embryos of our test species. Ultraviolet-B radiation is but one of several environmental variables which we intend to test. Funding: Declining Amphibian Population Task Force.1
Research Reports 1996-1997
Terrestrial Botany
Plant Population Ecology, Ecophysiology, and Genetics
Laurie Luedtke, Agronomy and Range Science, UC Davis
This research attempts to distinguish the genetic and environmental components of growth and reproductive variation in a common grass found in different habitats in the western United States. Bromus marginatus, Mountain Brome Grass, has been transplanted from a variety of sites to Valentine Camp. By growing the same species from different environments together I can determine if particular genotypes have higher growth rates or greater reproductive output, or whether the environment controls these factors. Funding: Self-funded.
Terrestrial ZoologyEcology of American Martens on the Inyo National Forest
Thomas E. Kucera, Division of Ecosystem Sciences, ESPM, UC Berkeley
The American marten (Martes americana) is a small (about 1 kg) mustelid endemic to North America. It is considered a habitat specialist, typically associated with late-successional coniferous forests with complex physical structure near the ground. Although still large, the current continental distribution of American martens is reduced from presettlement historical times. The goal of this study was to establish a baseline understanding of the ecology and distribution of American martens on the Inyo National Forest between Mammoth Lakes and June Lake, Mono County, California. Work on the national forest was conducted out of the Valentine Eastern Sierra Reserve. Eight male and 6 female martens were captured and received radio transmitters. Home-range sizes ranged from 0.5 to 15 km2 among females and 0.3 to 14.5 km2 among males. With some exceptions, animals in this study area maintained exclusive intrasexual home ranges (territories) with male territories overlapping those of females, a pattern typical of martens. Home ranges of martens included all vegetation series in the area, but were heavily weighted toward Red Fir, Jeffrey Pine, and Lodgepole Pine. Those rest sites in trees or tree remains were typically in large structures. The mean diameters of live trees, snags, logs, and stumps used as rest sites were about 1 m. Forty-nine rest sites (64%) occurred in stands with <40% canopy closure; 16 of these (21%) were in stands with <25% canopy closure. American martens in the Mammoth-to-June study area occupied all coniferous forest types present, from managed Jeffrey pine at 2300 m to subalpine conifer at 3200 m and above. Rest-site structures used by martens in the present study were almost universally large, and the forest stands around them were notably open. These martens, then, are using remnants of the previous forest within the present managed, second-growth stands to meet their rest-site requirements. To maintain martens, forests in the area should be managed to provide structural diversity, large-diameter trees, snags, and logs, and adequate prey. Funding: U. S. Forest Service, Inyo National Forest.
Effects of Ultraviolet-B Radiation on DNA Damage, DNA Repair, and Hatching Success in Bufo canorus, Rana muscosa, and Hyla regilla in Yosemite National Park
Walter J. Sadinski, Radiobiology and Environmental Health, UC San FranciscoParticipants: M. C. Wilson, Tetra Tech, Inc.
Our current work in Yosemite National Park is designed to determine whether reduced reproductive success might be causing reported declines in the abundance and distributions of populations of Yosemite toads (Bufo canorus), mountain yellow-legged frogs (Rana muscosa), and to a lesser extent, Pacific treefrogs (Hyla regilla). Locating breeding sites, assessing hatching success and success to metamorphosis at breeding sites, and conducting experimental tests of potential factors that might be causing any reductions in reproductive success, are included in this work. A major focus thus far has been to study whether ambient levels of ultraviolet-B radiation have caused any reductions in hatching success or have induced DNA damage among embryos of our test species. Ultraviolet-B radiation is but one of several environmental variables which we intend to test. While lodged at Valentine Camp during the spring and summer of 1997, we surveyed our principal study area, from Tuolumne Meadows to Tioga Pass, for new breeding sites, monitored and censused new and old breeding sites, and measured solar radiation at our study sites. These efforts were particularly valuable in enabling us to better understand the dynamics of reproductive efforts and success among the various subpopulations of Yosemite toads in this region of the park and to obtain data on the variation in solar irradiance between 1996 and 1997. These data are critical to our understanding of how radiation and other environmental factors might be influencing the abundance and distributions of Yosemite toads and our other study species. The data gathered during our stay at Valentine Camp are being combined with those generated during 1996, and will be submitted for publication during the fall of 1997. Funding: Declining Amphibian Population Task Force.
Geographic and Altitudinal Variation in Water Balance in the Lesser Migratory Grasshopper, Melanoplus sanguinipes.
Bryan Rourke, Department of Ecology and Evolutionary Bioloy, UCIrvineParticipants: K. Montooth, J. Mazza, R. Adams, UC Irvine
It has long been thought that the waxy coating on insect cuticles has allowed them to radiate into dry environments by providing an effective barrier to water loss. The water loss rate of insects increases slowly until a certain temperature is reached, whereupon the rate increases dramatically. This is attributed to the melting of the cuticular hydrocarbons constituting the waterproof layer. Genetically based variation in the melting point and composition of this layer have been demonstrated in geographically isolated populations of the California grasshopper, Melanoplus sanguinipes. It is hypothosized that water loss rates among those populations would also be different, with lower latitude populations exhibiting lower water loss rates commensurate with their hotter, more arid environments. The objectives of the project are to obtain laboratory water loss rates at different temperatures on field-caught adult grasshoppers, to obtain lipid melting point and composition data, to sample microhabitat temperature differences, and to compile historical climate data, all from several sites. This has been done at a number of reserves, including SNARL and Valentine Camp, because of the availability of long-term climate data. Funding: Sigma XI.
Pollination in Penstamon
Paul Wilson, Department of Biology, California State University at NorthridgeParticipants: J. Dilley, P. Bryce, R. Pillar, A. Kuhne, California State University at Northridge
We conducted preliminary testing of Pollen Presentation Theory (PPT), a theory that predicts how natural selection shapes the pollen-bearing anthers of flowers. PPT predicts that when pollinators are frequent and effective, plants that restrict pollen availability to individual pollinators will donate more pollen to other plants than those that allow visitors free access. When pollinators are scarce or ineffective, plants will be more successful as males if they present their pollen simultaneously. We tested two species of Penstamon, one allegedly bee pollinated, the other hummingbird pollinated. By contrasting the two species we are testing the hypotheses that (a) gradual pollen presentation is associated with frequent and effective pollinator visitation, (b) high nectar secretion is correlated with frequent visitation, and (c) gradual pollen presentation is secondarily correlated with high nectar secretion. Funding: Research and Sponsored Projects, California State University at Northridge.
Research Reports 1995-1996
Terrestrial Botany
Plant Population Ecology, Ecophysiology, and Genetics
Laurie Luedkte, Department of Agronomy and Range Science, UC Davis
This research attempts to distinguish the genetic and environmental components of growth and reproductive variation in a common grass found in different habitats in the western United States. Bromus marginatus, Mountain Brome Grass, has been transplanted from a variety of sites to Valentine Camp. By growing the same species from different environments together I can determine if particular genotypes have higher growth rates or greater reproductive output, or whether the environment controls these factors. This year I continued to monitor overwinter survivorship and growth rates of experimental plants.
Fire History of Jeffrey Pine and Sierra Nevada Upper Montane Forest Types
Scott L. Stephens, USDA Forest Service
The fire history of Jeffery Pine and Sierra Nevada upper montane forest types was investigated in the eastern Sierra Nevada near Mammoth Lakes, Mono County, California. Elevation varied from 2550-2575 meters in the fire history plots. Fire history information from 1593-1995 was obtained from 30 fire scarred Jeffrey, lodgepole, and western white pines and red firs. Mean fire intervals were 10.9 and 36.7 years for the Jeffrey pine and upper montane forest types, respectively. Intervals between fires recorded by individual trees varied from 4-21 years and 13-87 years for Jeffrey pine and upper montane forest types, respectively. The last fire in this area occurred in 1889. Significant differences (P=0.01) were found in Mean Fire Interval between the two forest types although they were separated by only 150 meters.
Terrestrial Zoology
Ecology of American Martens in the Eastern Sierra Nevada
Thomas E. Kucera, Department of Environmental Science, Policy, and Management (ESPM), UC Berkeley
Reginald H. Barrett, Department of ESPM, UC Berkeley
Participants: K. Chen, M. Fallon-McKnight, Department of ESPM, UC Berkeley
The American marten (Martes americana) is a small (about 1 kg) mustelid endemic to North America. Its historic distribution included the northern limit of trees in Alaska to the southern Sierra Nevada, east through forested areas to Newfoundland. It is a habitat specialist, often associated with late-successional coniferous forests with complex physical structure near the ground. The current continental distribution of American martens has been reduced from presettlement historical times. Particularly in the northeastern United States and on the West Coast, range contractions have been major. Habitat loss, mostly due to timber harvest, is blamed for most of this reduction. Region 5 (California) of the U.S.D.A. Forest Service lists the American marten as a "Sensitive" species in California (Macfarlane 1994). The goal of the present study is to establish baseline information on American marten ecology and distribution in the Inyo National Forest between Mammoth Lakes and June Lake, Mono County, California. Specific objectives include describing resting and foraging habitats of martens, determining home-range sizes and composition, and identifying their use of special habitat features such as logs or snags. A total of 13 martens, 7 males and 6 females, were captured live for radio telemetry between November, 1995, and March, 1996. Because the study has just been started, it is too early to discuss results. Funding: Inyo National Forest; UC Berkeley; Deep Springs College.
Research Reports 1993-1995
Animal Behavior/Physiology
Winter Furbearers
Tom Kucera, Environmental Science, Policy, and Management, UC Berkeley
A project to monitor winter furbearers at Valentine Camp was initiated with Tom Kucera of the Department of Environmental Science, Policy, and Management at UC Berkeley.
Brown-Headed Cowbird Abundance in the Sierra Nevada and Adjacent Regions
Steven I. Rothstien, Department of Biological Sciences, UC Santa Barbara
A. O. O'Loghlen: UC Santa Barbara
Cowbirds are a potential threat to other songbirds due to their broad parasitism and it is therefore valuable to determine whether they are increasing. In 1993, we repeated bird counts done in 1978. These sites were throughout the eastern Sierra region from the southern end of the range to the Bridgeport Valley. Overall, cowbirds showed a significant decline, especially in the Mammoth Lakes and other high-elevation areas. All other bird species were also counted in 1978 and 1993, and we will do analyses to determine whether other species have changed in relative abundance. Funding: USDA Forest Service.
Plant Ecology
Plant Population Ecology, Ecophysiology, and Genetics
Laurie Luedtke, Department of Agronomy and Range Science, UC Davis
Laurie is attempting to distinguish between the genetic and environmental components of variation in a common grass found in different habitats in the west. She has transplanted Bromus marginatus , Mountain Brome Grass, from a variety of sites to Valentine. By growing together the same species from different environments she can see if one particular genotype has higher growth rates or greater reproductive output or whether the environment is the controlling factor. This years research involved monitoring overwinter survivorship and growth rates of experimental plants.
Terrestrial Botany
Wetland Delineation in Long Valley
Robert Curry, Environmental Studies Board, UC Santa Cruz
C. Christian, B. Emery: UC Santa Cruz
As an extension of undergraduate courses in wetlands identification and delineation, we used undergraduate students to delineate wetlands on private property in Long Valley, Mono County, California. The project involved detailed soil sampling, plant sampling and identification and mapping. Funding: Lahonton Regional Water Quality Control Board, Mono County.
Plant Population Ecology, Ecophysiology, and Genetics
Laurie Luedkte, Department of Agronomy and Range Science, UC Davis
This research attempts to distinguish between the genetic and environmental components of variation in a common grass found in different habitats in the west. Bromus marginatus, Mountain Brome Grass, has been transplanted from a variety of sites to Valentine Camp. By growing together the same species from different environments it can be seen if one particular genotype has higher growth rates or greater reproductive output, or whether the environment is the controlling factor. This year's research continued to monitor overwinter survivorship and growth rates of experimental plants.
Fire Ecology of Valentine Camp
Scott Stephens, Department of Environmental Science, Policy and Management, UC Berkeley
D. R. Dawson, S. Christensen: Valentine Camp
As a result of approximately 120 years of fire suppression in the Sierra Nevada, fuel loads at Valentine Camp have become very high. With public land on two sides, and private land on the others, Valentine is a good example of fire management problems that occur at the urban/wildland interface. As a first step in developing a fire management plan for the reserve, we have attempted to determine past fire regimes with the goal of understanding the ecological role of fire in this system. We have cut slabs out of 30 fire-scarred trees. The slabs then get sanded, and the approximate dates and recurrence intervals of the fire events are determined from tree ring analysis. Preliminary assessment of the available data looks good with some trees having as many as seven fire events. Funding: Valentine Endowment.
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