Wildlife
in a Changing Climate
Sarah Stock
Wildlife Biologist, Yosemite National Park
DEPO Hydroclimate Workshop
Yosemite National Park
October 8, 2008
Yosemite National Park
U.S. Department of the Interior
National Park Service
Grappling with climate
change…
“To meet the challenges of understanding
and communicating the effects that
climate change will have on bird
populations, it is imperative that
ornithologists begin to develop and
maintain a working knowledge of climate
models, emissions scenarios, and the
capabilities and limitations of climate
projections.”
Seavy et al. 2008
Approach – Climate Implications
1. Identify changes and trends
2. Demographic data to better understand
causation
3. Develop hypotheses that integrate
weather data
enable ecological
interpretations related to climate
projections
Yosemite Wildlife Research
Grinnell Resurvey
Jim Patton and Craig Moritz,
Museum of Vertebrate Zoology,
U.C. Berkeley
Songbird Monitoring
Rodney Siegel, Institute For Bird
Populations
Grinnell Resurvey
• 1914 – 1920: Original vertebrate surveys
• 2003 – 2006: Repeated surveys
Grinnell Resurvey
• Small mammal and Bird ranges – shifts up-slope
in elevation
- E.g., pikas
• Grinnell: 7,800 feet and upward
• Present: above 9,500 feet
- E.g., Lyell Fork
By: CDonGettiPhoto.com
• 5 bird species not detected
• 17 bird species added
Is climate change a factor driving
these shifts?
Jeff Foott
Song Sparrow
Songbird Monitoring
MAPS –
Monitoring Avian Productivity and Survivorship
– 1990-2008
– 5 stations
– Measures
• population trends
• demographic metrics
(productivity & survivorship)
Songbird Monitoring in Yosemite
Trend Data • 23% reduction in landbird abundance
• significant negative population trends for
13 species
Demographic • seven of those declining species show low
productivity
Climate related Hypotheses
Effect of spring
snowpack on
annual # of
young birds?
Timing of snowpack melt is highly variable
from year to year…
H1: Late spring snowpack Æfewer young produced,
because
-late snowfall causes early nesting attempts to
fail (reduced reproductive success)
-lingering snowpack prevents early nesting
attempts (reduced reproductive effort)
H0: Late spring snowpack Ælittle or no effect on the
number of young produced
No. of young per 600 net-hours
Negative relationship between spring
snowpack and # of young produced –
all species pooled
Mean daily April snow depth (cm) at Gin Flat
No. of young per 600 net-hours
Strong positive relationship between
spring snowpack and # of young produced
Mean daily April snow depth (cm) at Gin Flat
Implications
• Requires targeted research for mechanistic
understanding—monitor nesting attempts!
• Many species may be quite sensitive to projected climate
change; some may actually benefit from reduced spring
snowpack
(Even under this scenario, there may be other
deleterious effects of climate change, e.g., asynchrony
with food resources, shifts in breeding range, etc.)
Implications… for DEPO
Considerations
• Other climate change predictions more relevant than
upslope shifts in distributions?
– Migration timing: birds arriving earlier, departing later?
– Populations nesting farther North?
– Asynchrony in food sources (insects hatching and plants flowering
earlier) with reproductive behavior
• Sierra Bird Decline – Are population trends localized (sitespecific) or consistent with declines seen elsewhere in
Sierra?
• Draw on historical data for “snapshots” in time
• Identify focal species that could be responding to climate
change
– E.g., Breeding populations of Neotropical migrants in riparian
habitats
• Integrate models of climate change with population trends
Acknowledgements
Rodney Siegel, Dave DeSante
Institute for Bird Populations
Jim Patton, Craig Moritz
Museum of Vertebrate Zoology, UC
Berkeley
Yosemite Fund