The mid-elevation forest of California's Sierra Nevada poses a bioclimatic paradox. Mid-eleva... more The mid-elevation forest of California's Sierra Nevada poses a bioclimatic paradox. Mid-elevation trees experience a montane Mediterranean climate, with near-freezing winter days and rain-free summers. The asynchrony between warmth and water input suggests low primary production, limited by photosynthetic dormancy in winter cold, and again in summer and early autumn with drought, yet this forest is characterized by tall trees and high biomass. We used eddy covariance in a mid-elevation Sierra stand to understand how winter cold and summer drought limit canopy photosynthesis and production. The trees exhibited canopy photosynthesis year-round. Trees avoided winter dormancy, and daytime CO2 uptake continued despite a deep snowpack and near-freezing temperatures. Photosynthesis on sunny days continued at half of maximum rates when air temperature was 0 °C. Likewise, the vegetation avoided summer drought dormancy, and high rates of daytime CO2 uptake and transpiration continued desp...
Workshop to Promote Safety in Field Sciences (SIFS), Virtual., 2021
Report of the Workshop to Promote Safety in Field Sciences that was organized by CSU Desert Studi... more Report of the Workshop to Promote Safety in Field Sciences that was organized by CSU Desert Studies and the Consortium for Ocean Leadership on 24-26 March 2021. The workshop resulted in 52 recommendations targeted at improving field science culture change, as well as misconduct accountability, policy, and reporting. Diversity, equity, inclusion, and justice (DEIJ) and trainings were additional cross-cutting topics. The recommendations focus on improving experiences for field participants of all backgrounds and identities. The recommendations represent a starting point, and we hope that the report will inspire and guide different audiences and actors in field science in implementing some or all of these recommendations, and to do so in a collaborative, community-based way.
Rising temperatures and declining water availability have influenced the ecological function of m... more Rising temperatures and declining water availability have influenced the ecological function of mountain forests over the past half-century. For instance, warming in spring and summer and shifts towards earlier snowmelt are associated with an increase in wildfire activity and tree mortality in mountain forests in the western United States 1,2 . Temperature increases are expected to continue during the twenty-first century in mountain ecosystems across the globe 3,4 , with uncertain consequences. Here, we examine the influence of interannual variations in snowpack accumulation on forest greenness in the Sierra Nevada Mountains, California, between 1982 and 2006. Using observational records of snow accumulation and satellite data on vegetation greenness we show that vegetation greenness increases with snow accumulation. Indeed, we show that variations in maximum snow accumulation explain over 50% of the interannual variability in peak forest greenness across the Sierra Nevada region. ...
Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports... more Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone ...
Author(s): Kelly, Anne E. | Advisor(s): Goulden, Michael L | Abstract: The association between cl... more Author(s): Kelly, Anne E. | Advisor(s): Goulden, Michael L | Abstract: The association between climate and vegetation distribution has long been acknowledged, but quantifying the limits of climate on vegetation growth, biomass, and mortality remains an unsolved problem. Accurate prediction of the effects of climate change requires an understanding of the physiological limitations on vegetation due to climate. Recent increases in forest mortality and wildfire in Western North America has been attributed to warming and drought, but the causal mechanisms have not been identified. This dissertation uses observations of weather and vegetation growth, biomass, and water use to compare diverse ecosystems' responses to temperature and water availability and identify physiological thresholds that could promote ecosystem resilience or vulnerability to climate change. The second chapter constructs a diagnostic framework of climatic control on biomass. The study system was the western slope...
Anne Kelly The Deep Canyon Transect in the Santa Rosa Mountains of Southern California spans 2560... more Anne Kelly The Deep Canyon Transect in the Santa Rosa Mountains of Southern California spans 2560 m in elevation and four major plant communities: desert scrub, Sonoran pinyon-juniper woodland, montane chaparral, and mixed conifer forest. The plant species distributions of the Deep Canyon Transect were compared from 1977 to 2007 and the causes of change were examined. We hypothesized plant species distributions to move upwards in elevation in response to climate warming and increasing climate variability. In ...
Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports... more Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone ...
The NASA/IPAC Extragalactic Database (NED,http://ned.ipac.caltech.edu/) currently contains over 4... more The NASA/IPAC Extragalactic Database (NED,http://ned.ipac.caltech.edu/) currently contains over 4.5 million photometric measurements covering the electromagnetic spectrum from gamma rays through radio wavelengths for objects that are being cross-correlated among major sky surveys (e.g., SDSS, 2MASS, IRAS, NVSS, FIRST) and thousands of smaller, but unique and important, catalogs and journal articles. The ability to retrieve photometric data (including uncertainties, aperture information,
S. G. Djorgovski, R. R. Gal, S. R. Kulkarni, J. S. Bloom, and A. Kelly,
on behalf of the Caltech... more S. G. Djorgovski, R. R. Gal, S. R. Kulkarni, J. S. Bloom, and A. Kelly,
on behalf of the Caltech GRB Collaboration, report:
"We obtained multicolor (BVRri) CCD images of the field of GRB 980519
(see GCN Circ. 75), using Palomar Observatory 200-inch and 60-inch
telescopes, on UT May 20.
We confirm the optical transient (OT) discovered by Jaunsen et al.
(GCN Circ. 78). The object is continuing to fade. Using the magnitudes
of stars B and C of Jaunsen et al. (their star A gives discrepant results)
to tie in the instrumental magnitude systems, we derive for the OT:
I = 21.46 (+- 0.1) in this magnitude system, on UT May 20.436 (mean epoch).
Comparing with the value of I = 20.08 mag in the same system on UT May 20.00
from Jaunsen et al., we derive the power-law decline slope of -1.98 for the
I-band light curve. This is fully consistent with the relative V-band
light curve given at http://www.uio.no/~ajaunsen/grb980519.
These measurements are preliminary. A more detailed analysis of the data
is in progress.
Southern California's pine forests have experienced widespread mortality in the past few yea... more Southern California's pine forests have experienced widespread mortality in the past few years. In Deep Canyon, California, this death seems to be caused by increasing drought and warmer winters. While conifers are the most obviously affected, they are not the only species experiencing collapse. By using elevation gradients as a proxy for temperature and precipitation gradients, one would expect to see species ranges moving upward along a slope in a drying climate. I have compared Zabriskie's 1977 study of the Deep Canyon ...
Southern California's pine forests have experienced widespread mortality in the past few yea... more Southern California's pine forests have experienced widespread mortality in the past few years. In Deep Canyon, California, this death seems to be caused by increasing drought and warmer winters. While conifers are the most obviously affected, they are not the only species experiencing collapse. By using elevation gradients as a proxy for temperature and precipitation gradients, one would expect to see species ranges moving upward along a slope in a drying climate. I have compared Zabriskie's 1977 study of the Deep Canyon ...
Abstract The Mediterranean climate of California's Sierra Nevada Mountains supports a dense ... more Abstract The Mediterranean climate of California's Sierra Nevada Mountains supports a dense conifer forest that contains some of the largest trees in the world. Well-established ecological relationships, such as the Miami Model, predict relatively low NPPs for these forests (~ 250 g/m2/yr to 1300 g/m2/yr) due to winter cold limitation and summer drought. However, the observed rates of NPPs are quite high (up to 2000 g/m2/yr), raising the question of what environmental conditions and plant adaptations promote such a high ...
The mid-elevation forest of California's Sierra Nevada poses a bioclimatic paradox. Mid-eleva... more The mid-elevation forest of California's Sierra Nevada poses a bioclimatic paradox. Mid-elevation trees experience a montane Mediterranean climate, with near-freezing winter days and rain-free summers. The asynchrony between warmth and water input suggests low primary production, limited by photosynthetic dormancy in winter cold, and again in summer and early autumn with drought, yet this forest is characterized by tall trees and high biomass. We used eddy covariance in a mid-elevation Sierra stand to understand how winter cold and summer drought limit canopy photosynthesis and production. The trees exhibited canopy photosynthesis year-round. Trees avoided winter dormancy, and daytime CO2 uptake continued despite a deep snowpack and near-freezing temperatures. Photosynthesis on sunny days continued at half of maximum rates when air temperature was 0 °C. Likewise, the vegetation avoided summer drought dormancy, and high rates of daytime CO2 uptake and transpiration continued desp...
Workshop to Promote Safety in Field Sciences (SIFS), Virtual., 2021
Report of the Workshop to Promote Safety in Field Sciences that was organized by CSU Desert Studi... more Report of the Workshop to Promote Safety in Field Sciences that was organized by CSU Desert Studies and the Consortium for Ocean Leadership on 24-26 March 2021. The workshop resulted in 52 recommendations targeted at improving field science culture change, as well as misconduct accountability, policy, and reporting. Diversity, equity, inclusion, and justice (DEIJ) and trainings were additional cross-cutting topics. The recommendations focus on improving experiences for field participants of all backgrounds and identities. The recommendations represent a starting point, and we hope that the report will inspire and guide different audiences and actors in field science in implementing some or all of these recommendations, and to do so in a collaborative, community-based way.
Rising temperatures and declining water availability have influenced the ecological function of m... more Rising temperatures and declining water availability have influenced the ecological function of mountain forests over the past half-century. For instance, warming in spring and summer and shifts towards earlier snowmelt are associated with an increase in wildfire activity and tree mortality in mountain forests in the western United States 1,2 . Temperature increases are expected to continue during the twenty-first century in mountain ecosystems across the globe 3,4 , with uncertain consequences. Here, we examine the influence of interannual variations in snowpack accumulation on forest greenness in the Sierra Nevada Mountains, California, between 1982 and 2006. Using observational records of snow accumulation and satellite data on vegetation greenness we show that vegetation greenness increases with snow accumulation. Indeed, we show that variations in maximum snow accumulation explain over 50% of the interannual variability in peak forest greenness across the Sierra Nevada region. ...
Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports... more Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone ...
Author(s): Kelly, Anne E. | Advisor(s): Goulden, Michael L | Abstract: The association between cl... more Author(s): Kelly, Anne E. | Advisor(s): Goulden, Michael L | Abstract: The association between climate and vegetation distribution has long been acknowledged, but quantifying the limits of climate on vegetation growth, biomass, and mortality remains an unsolved problem. Accurate prediction of the effects of climate change requires an understanding of the physiological limitations on vegetation due to climate. Recent increases in forest mortality and wildfire in Western North America has been attributed to warming and drought, but the causal mechanisms have not been identified. This dissertation uses observations of weather and vegetation growth, biomass, and water use to compare diverse ecosystems' responses to temperature and water availability and identify physiological thresholds that could promote ecosystem resilience or vulnerability to climate change. The second chapter constructs a diagnostic framework of climatic control on biomass. The study system was the western slope...
Anne Kelly The Deep Canyon Transect in the Santa Rosa Mountains of Southern California spans 2560... more Anne Kelly The Deep Canyon Transect in the Santa Rosa Mountains of Southern California spans 2560 m in elevation and four major plant communities: desert scrub, Sonoran pinyon-juniper woodland, montane chaparral, and mixed conifer forest. The plant species distributions of the Deep Canyon Transect were compared from 1977 to 2007 and the causes of change were examined. We hypothesized plant species distributions to move upwards in elevation in response to climate warming and increasing climate variability. In ...
Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports... more Abstract The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone ...
The NASA/IPAC Extragalactic Database (NED,http://ned.ipac.caltech.edu/) currently contains over 4... more The NASA/IPAC Extragalactic Database (NED,http://ned.ipac.caltech.edu/) currently contains over 4.5 million photometric measurements covering the electromagnetic spectrum from gamma rays through radio wavelengths for objects that are being cross-correlated among major sky surveys (e.g., SDSS, 2MASS, IRAS, NVSS, FIRST) and thousands of smaller, but unique and important, catalogs and journal articles. The ability to retrieve photometric data (including uncertainties, aperture information,
S. G. Djorgovski, R. R. Gal, S. R. Kulkarni, J. S. Bloom, and A. Kelly,
on behalf of the Caltech... more S. G. Djorgovski, R. R. Gal, S. R. Kulkarni, J. S. Bloom, and A. Kelly,
on behalf of the Caltech GRB Collaboration, report:
"We obtained multicolor (BVRri) CCD images of the field of GRB 980519
(see GCN Circ. 75), using Palomar Observatory 200-inch and 60-inch
telescopes, on UT May 20.
We confirm the optical transient (OT) discovered by Jaunsen et al.
(GCN Circ. 78). The object is continuing to fade. Using the magnitudes
of stars B and C of Jaunsen et al. (their star A gives discrepant results)
to tie in the instrumental magnitude systems, we derive for the OT:
I = 21.46 (+- 0.1) in this magnitude system, on UT May 20.436 (mean epoch).
Comparing with the value of I = 20.08 mag in the same system on UT May 20.00
from Jaunsen et al., we derive the power-law decline slope of -1.98 for the
I-band light curve. This is fully consistent with the relative V-band
light curve given at http://www.uio.no/~ajaunsen/grb980519.
These measurements are preliminary. A more detailed analysis of the data
is in progress.
Southern California's pine forests have experienced widespread mortality in the past few yea... more Southern California's pine forests have experienced widespread mortality in the past few years. In Deep Canyon, California, this death seems to be caused by increasing drought and warmer winters. While conifers are the most obviously affected, they are not the only species experiencing collapse. By using elevation gradients as a proxy for temperature and precipitation gradients, one would expect to see species ranges moving upward along a slope in a drying climate. I have compared Zabriskie's 1977 study of the Deep Canyon ...
Southern California's pine forests have experienced widespread mortality in the past few yea... more Southern California's pine forests have experienced widespread mortality in the past few years. In Deep Canyon, California, this death seems to be caused by increasing drought and warmer winters. While conifers are the most obviously affected, they are not the only species experiencing collapse. By using elevation gradients as a proxy for temperature and precipitation gradients, one would expect to see species ranges moving upward along a slope in a drying climate. I have compared Zabriskie's 1977 study of the Deep Canyon ...
Abstract The Mediterranean climate of California's Sierra Nevada Mountains supports a dense ... more Abstract The Mediterranean climate of California's Sierra Nevada Mountains supports a dense conifer forest that contains some of the largest trees in the world. Well-established ecological relationships, such as the Miami Model, predict relatively low NPPs for these forests (~ 250 g/m2/yr to 1300 g/m2/yr) due to winter cold limitation and summer drought. However, the observed rates of NPPs are quite high (up to 2000 g/m2/yr), raising the question of what environmental conditions and plant adaptations promote such a high ...
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Papers by Anne E Kelly
on behalf of the Caltech GRB Collaboration, report:
"We obtained multicolor (BVRri) CCD images of the field of GRB 980519
(see GCN Circ. 75), using Palomar Observatory 200-inch and 60-inch
telescopes, on UT May 20.
We confirm the optical transient (OT) discovered by Jaunsen et al.
(GCN Circ. 78). The object is continuing to fade. Using the magnitudes
of stars B and C of Jaunsen et al. (their star A gives discrepant results)
to tie in the instrumental magnitude systems, we derive for the OT:
I = 21.46 (+- 0.1) in this magnitude system, on UT May 20.436 (mean epoch).
Comparing with the value of I = 20.08 mag in the same system on UT May 20.00
from Jaunsen et al., we derive the power-law decline slope of -1.98 for the
I-band light curve. This is fully consistent with the relative V-band
light curve given at http://www.uio.no/~ajaunsen/grb980519.
These measurements are preliminary. A more detailed analysis of the data
is in progress.
This note can be cited.
on behalf of the Caltech GRB Collaboration, report:
"We obtained multicolor (BVRri) CCD images of the field of GRB 980519
(see GCN Circ. 75), using Palomar Observatory 200-inch and 60-inch
telescopes, on UT May 20.
We confirm the optical transient (OT) discovered by Jaunsen et al.
(GCN Circ. 78). The object is continuing to fade. Using the magnitudes
of stars B and C of Jaunsen et al. (their star A gives discrepant results)
to tie in the instrumental magnitude systems, we derive for the OT:
I = 21.46 (+- 0.1) in this magnitude system, on UT May 20.436 (mean epoch).
Comparing with the value of I = 20.08 mag in the same system on UT May 20.00
from Jaunsen et al., we derive the power-law decline slope of -1.98 for the
I-band light curve. This is fully consistent with the relative V-band
light curve given at http://www.uio.no/~ajaunsen/grb980519.
These measurements are preliminary. A more detailed analysis of the data
is in progress.
This note can be cited.