Join Caroline Williams, PhD and Eric Riddell, PhD as they discuss their research involving climate change and the ecophysiological effects of changing global temperatures on organismal biology and survival.
Key Topics Include:
Energy use models using microclimate data can accurately predict whole winter energy use.
Colder soils in a warmer world: Snow modulates a trade-off between cold exposure and energy use for soil dwelling organisms.
How processes at the genetic level can influence ecological processes, such as geographic ranges.
Complex methods to make realistic predictions on the ecological impact of climate change.
Physiochemical properties of nanomaterials and its nanotoxicity.pptx
Ecophysiological Impacts of Climate Change: Performance, Fitness and Extinction
1. Ecophysiological Impacts of
Climate Change: Performance,
Fitness, and Extinction
Eric Riddell, PhD
Assistant Professor
Ecology, Evolution, and Organismal Biology (EEOB)
Iowa State University
Caroline Williams, PhD
Associate Professor
Integrative Biology
University of California, Berkeley
2. Experts discuss their research involving
climate change and the ecophysiological
effects of changing global temperatures
on organismal biology and survival.
Ecophysiological Impacts of
Climate Change: Performance,
Fitness, and Extinction
3. Winter in a Changing World:
The Critical Importance of Snow
Copyright 2021 C. Williams and InsideScientific. All Rights Reserved.
Caroline Williams, PhD
Associate Professor
Integrative Biology
University of California, Berkeley
5. Winter warming is having widespread
impacts on biodiversity
Osland et al. 2021 Global Change Biology
6. Winter warming decreases snowpack
Mote et al. 2018. Clim. Atmos. Sci.
Northern hemisphere spring snowpack
anomalies, 1980 - 2020
Marshall et al. 2020 Curr Opin Insect Sci
Red = decreased
snowpack
Spring snowpack changes,
1955-2016
Sierra Nevada
mountain range,
California USA
7. Snow cover fluctuates in the Sierra Nevada
Joshua Cripps Photography
June 22nd 2006
June 22nd 2007
Nathan Rank
8. Many ectotherms overwinter beneath snow
AgPest.co.nz
Ferdinand Bada
Andy Murray
Joseph Berger
Tristram Brelstraff
Jon Costanza
9. Snow determines soil microclimate, and thermal stress
Cold snap
Big snow fall
“Colder soils in a warmer world”
-Groffman, 2001
10. Sources of mortality in winter
Energy depletion
Cold mortality
Colder soils in a warmer world:
Loss of snow cover will increase cold stress but decrease energy stress
11. Organismal traits determine response to
microclimate temperatures
Sinclair et al. 2015 J. Therm Biol
Irwin & Lee. 2003 Oikos
Energy use Cold tolerance
Metabolic
rate
Temperature
LT50 (1hr exposure)
12. Moving up a
mountain…
We do not know
how thermal
stress on
overwintering
ectotherms in the
soil changes
along a snowy
elevational
gradient
Energy
depletion
Cold
mortality
Soil temperature ???
Air temperature
Snow cover
13. Research question
How does changing snow cover impact cold and
energetic stress, for organisms that overwinter in
the soil in snowy mountains?
14. Sierra willow leaf beetle,
Chrysomela aeneicollis
Southern range edge of species range
illustrations: Hiroko Udaka
Sierra Nevada
15. Rich history of study
1980 – 2020
Microclimate
monitoring network
Beetle surveys
Physiology and
genetics
Collaborators Elizabeth Dahlhoff and Nathan Rank, with
PhD candidate Kevin Roberts
Bishop CA
16. How does snow impact cold stress and energy stress on
overwintering beetles along an elevational gradient?
Environment
Microclimate temperatures
Spatial and temporal variation in
snow cover
Laboratory
Metabolic rate-temperature
curves
Cold tolerance limits (acute and
chronic exposures)
Energy reserve assays
Field
Population surveys (phenology)
Snow manipulation experiments
Ecophysiological Models
Energy and Cold Stress
test
test
Kevin Roberts
17. Environment: spatial and temporal
variation in snow cover
Roberts et al. in review GCB
Snowy
Dry
28 sites,
1980 – 2020
Hourly soil
temperatures
5 replicate transects
Bishop CA
Spatial variation Interannual variation
climate
change
18. Snow alters elevational gradients
in cold exposure
Cold exposure peaks at
mid-elevation, and is
higher in dry years
Roberts et al. in review GCB
19. Ecophysiological energy use model
1) Estimate metabolic rate –
temperature curves using respirometry
2) Input microclimate data to estimate
oxygen consumption throughout winter
3) Select start and end dates and sum to
get oxygen used over winter (repeat
iteratively for range of start and end
dates observed in field)
4) Convert to energy used (2L oxygen =
1g lipid, compare to empirical
measurements
Snow
Present
Snow
Excluded
Field
Experiment
0.589 mg 0.398 mg
Model
Estimate
0.591 mg 0.417 mg
Model
Accuracy
99.7% 95.2%
Validated model is >95%
accurate in predicting energy use
in snowy and dry conditions
21. Energy use across elevation
Energy use declines with
increasing elevation, steeper
decline in snowy years due
to very high energy use at
low elevations
Snowy years are longer, and
more energetically demanding
Roberts et al. in review GCB
22. Climate change will alter cold exposure
and energy use across the mountains
Long Lake, Bishop Creek
Roberts et al. in review GCB
23. Cold mortality likely occurs due to long freezing
periods
LT50 (1hr exposure)
Lethal time frozen
24. Cold and energy stress across elevation
• Probability of lethal
cold is highest at
mid-elevations, not
impacted by
interannual variation
in snow cover
Roberts et al. in review GCB
25. • Probability of lethal
cold is highest at
mid-elevations, not
impacted by
interannual variation
in snow cover
• Probability of lethal
energy depletion is
highest at low
elevations, and in
snowy years
Cold and energy stress across elevation
Roberts et al. in review GCB
26. Conclusions
• Trade-off between cold mortality and energy depletion is
modulated by interannual variation in snow cover
• Snow alters elevational gradients in cold and energy stress,
potentially altering selective gradients on these traits for
overwintering ectotherms
• Impact of interannual variation in snow cover depends on
elevation – high elevations will be buffered due to persistent
snow cover, and mid elevations will experience increased cold
stress
• Environment (microclimate) and organismal traits together
determine stress exposure
28. Thank you!
Collaborators:
Kevin Roberts
Nathan Rank
Elizabeth Dahlhoff
Jonathon Stillman
Doris Bachtrog
Ryan Bracewell
Andre Szejner Sigal
Lisa Treidel
Christina Lee
Varun Bahl
Rose Kang
Kamalakar Chatla
Colleagues:
Brent Sinclair
Dan Hahn
Ray Huey
John Smiley
Greg Ragland
Michael Kearney
Research Facilitation:
White Mountain Research Station
Denise Waterbury
Williams lab: Ecological and Evolutionary Physiology
https://www.cmwilliamslab.com/
Sable Systems for all the great respirometry equipment!
29. Using Ecophysiology to
Predict Extinction Risk
From Climate Change
Copyright 2021 E. Riddell and InsideScientific. All Rights Reserved.
Eric Riddell, PhD
Assistant Professor
Ecology, Evolution, and Organismal Biology (EEOB)
Iowa State University
69. Net energy balance (J)
Activity time (hr)
30-
0 -
-30-
7-
3.5-
0-
Riddell et al. 2017; Ecol. Monogr.
83% of known localities can reproduce
Physiology helps to predict geographic range of salamanders
70. 30-
0 -
-30-
7-
3.5-
0-
Physiology helps to predict geographic range of salamanders
Riddell et al. 2017; Ecol. Monogr.
Net energy balance (J)
Activity time (hr)
83% of known localities can reproduce
116. Collaborators
Steve Beissinger
Mike Sears
Blair Wolf
Barry Sinervo
Cameron Ghalambor
Kelly Zamudio
Christina Wells
Robert Baldwin
Kyle Barrett
Michael Carlo
Ofir Levy
Scott Sillett
Evan Apanovich
Danielle Perryman
Richard Ramirez
Kelly Iknayan
Undergraduates
Carlie Blankenship
Justyn Plaskon
Jared McPhail
Jonathan Odom
Jason Damm
Meredith Rutledge
Megan Matlack
Lunden Simpson
Chris Gerstle
Faye Romero
Megan Banke
Josh Vanee
Walid Naseri
Emma Roback
Jennifer Tutijan
Riggs Mathews
Acknowledgements
117. Eric Riddell, PhD
Assistant Professor
Ecology, Evolution, and Organismal Biology (EEOB)
Iowa State University
Caroline Williams, PhD
Associate Professor
Integrative Biology
University of California, Berkeley
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