Managing for species diversity under
climate change: implications of future
change for prairie dogs and their
cohorts
Megan Friggens
Rocky Mountain Research Station
August 20, 2011
Today’s discussion
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Black-tailed prairie dogs and their
ecosystems
Climate change and prairie dogs
Future risk of Plague (Yersinia pestis)
Prairie Dogs in the Great Plains
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Prairie dogs are medium
sized mammals that live in
large colonies
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Historically, prairie dogs
were a major component
of the grazing community
of central north American
grasslands
Mark E. Marcusum
Area covered by grasslands in tan
and yellow
Historic Range of the Black Tailed Prairie
Dog
Prairie dogs have declined by 98%
from this historic range!
Issues facing prairie dogs
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Land Conversion
Eradication efforts
Hunting
Pet trade
Plague
Implications for ecosystems
Prey
Ecosystem Engineers
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Endangered since 1967
No known natural
populations
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At risk due to prairie dog
declines, distemper, and
plague
Captive breeding began in
1980’s with 25 individuals
The success of current
reintroduction efforts in
10 states depends upon
sustained colonies of
prairie dogs.
Credit: R. List (http://www.blackfootedferret.org/
Vertebrate associates
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Mountain Plovers show sharp declines in nest sites
following plague related reductions in prairie dogs.
Wildearthorigin.org
From Augustine et al. 2008
Landscape Ecology
Little herbivore, big impact
Prairie dogs present
Russian
Thistle
Prairie dogs
absent
(1.5yrs)
Modified from Davidson et al. 2010
Prairie dogs and species composition
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Greater diversity on towns
Many native plants, globe mallow,
buffalo grass, associated with
towns
Prairie dog towns are:
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Exotic species
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conducive to establishment of
weedy species and often a refugia
for native species
Towns have less exotic cheat grass
(Bromus tectorum)
Towns have poor seedbanks of
exotic species
Though disturbance favors
establishment, foraging behaviors
prevents spread of exotic species
From: Larson 2003; Fahnestock et al. 2003
Prairie dogs and shrub establishment
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Mixed grass prairie: Mesquite more dense on towns but with
reduced height and lower seedling and sapling survival
Desert Grassland: Rapid shrub encroachment after loss of
prairie dog towns
2002
2006
From: Weltzin et al. 1997 Ecology; Ceballos et al. 2010 PLOS
Implications of Climate Change
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Changes in habitat resulting from prairie dog activity
may accelerate or mitigate the consequences of
climate change
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Loss of grasslands
Increased desertification
Fire regimes
Spread of exotic species
Shrub encroachment/
transition to shrublands
Maintenance of species
diversity
Climate change will also affect Prairie dogs
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Longer growing season, higher temperatures,
changes to fire regimes and increased variability in
weather events will effect:
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Prairie dog food sources
Prairie dog predators and competitors
Habitat suitability of sites
Risk of plague outbreaks
Plague and Prairie Dogs
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Plague (Yersinia pestis) is a
blood-borne pathogen
Relies on transmission by
fleas
Reservoirs are commonly
rodents (not prairie dogs!)
Introduced to U.S. in 1900
Seasonality
Disease is cyclical and changes as
reservoir and vector populations
increase/decrease
Plague is strongly impacted by climate
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Plague outbreaks are influenced by temperature due
to effects on both plague bacterium and flea vectors
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Too cold, no fleas
Too hot, bacteria cannot infect fleas
Weather conditions that favor rodent reservoirs or
flea populations also favors spread of plague
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Madagascar- outbreaks during cool, dry season
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China-relationship between El Niño years and incidence
of human plague cases
Grasshopper
mouse, the
likely culprit for
spread of plague
in Northern CO
(Cavenaugh, 1971; Davis et al., 2004; Boisier et al., 2002; Zhang et al., 2007; Stenseth et al. 2006; Park, 2007 )
Kazakhstan
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1 C increase lead to >50% increase in prevalence of plague in rodent
populations
Climate conditions in this area were conducive to plague outbreak of
middle ages
Climate warming is likely to lead to more outbreaks
Stenseth, et al. (2006) Proc. Natl. Acad. Sci. USA 103, 13110-13115
Copyright ©2006 by the National Academy of Sciences
What do we know about climate and plague
outbreaks in the U.S.?
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In the Pawnee National Grasslands, black-tailed prairie
dogs plague outbreaks follow El Niño events.
Credit: Colorado Ben
From: Stapp et al. 2004
El Niño events are
associated with relatively
mild winters in this
regions
Probably an effect of
climate via the impact to
flea populations
What else do we know about climate and
plague outbreaks in the U.S.?
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In the SW, plague outbreaks have been associated with
previous years’ precipitation and both upper and lower
temperature thresholds
This is thought to be driven
largely by cascading effects of
weather on primary
productivity and, ultimately, the
rodent host populations
(From: Parmenter et al., 1999; Enscore et al., 2002)
Risk of plague is likely to vary among
regions.
Cascading effect of rain on plague in
SW
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Increased rain=increase primary
productivity and greater flea survival
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Plague outbreaks increase with
increases in flea and rodent
populations
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Risk of plague is likely to vary among
regions.
Risk of plague in future depends on
both direct and indirect effects of
climate change
Regional patterns will depend upon
effect of:
Limiters (Precipitation vs. Cold)
Extended growing season
Host-vector effects
Cascading effect relating to new
host/flea interactions
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What does this mean for the future of
plague in the U.S.?
Future focus?
Current focus
Managing for Grassland Diversity
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Adaptive management
Consider mixed use sites
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Mixed herbivore communities
to maximize diversity
Use herbivores + fire
Preserve prairie dog colonies
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Regulate threats that can be
managed
Develop and maintain refuges
Consider supplemental feeding
and translocations
New ARS studies show that cattle,
prairie dogs, and fire all play an
important role in maintaining the
diversity of plants and wildlife of the
western Great Plains. Photo by ARS.
Managing for plague
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Consider future potential
plague risk for:
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Burrow treatments
Vaccinations
Relocations
Care needs to be taken
when designing preserves
or establishing new
colonies
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Large vs. small colonies
Design mix of isolated and
interconnected complexes
David Jachowski sprays insecticide
dust into a prairie dog burrow at the
boundary of Badlands National Park.