Theoretical Frameworks for Understanding Fire Refugia in Northern

Theoretical
Frameworks for
Understanding Fire
Refugia in Northern
Rocky Mountain
Ecosystems
US-CAN border, Paysaten Wilderness
Photo by Craig Parsley
Acknowledgements
Research Team
• Geneva Chong, Northern Rocky Mt. and North Central Climate Science
Centers, US Geological Survey
• Enric Batllori, University of California, Berkeley
• Jonathan Coop, Western State Colorado University
• Sandra Haire, Haire Laboratory for Landscape Ecology
• Meg Krawchuk, Simon Fraser University
• Carol Miller, Aldo Leopold Wilderness Research Institute, US Forest Service
• Marc-André Parisien, Northern Forest Centre, Canadian Forest Service
• Ellen Whitman, Simon Fraser University
2
Role of theory
Theory in ecology: context for
new ideas as problems emerge
Rapidly changing climate and
fire regimes with unknown
consequences for
biodiversity
Allen et al. 2010, Wooton et al. 2010,
Turner et al. 2012 and others.
3
Project background
Contemporary problems for
ecology
Can refugia be identified within burned landscapes that offer
short- or longer-term habitats for species and communities?
4
Research approach
Theoretical frameworks:
formation of refugia
Spatial context:
topographic wind/fire breaks
Microclimate:
cooler, moister, less flammable
Weathersolve.com
Winstral, A., et al. 2002. Spatial snow modeling of windredistributed snow using terrain-based parameters. Journal of
Hydrometeorology
Dobrowski, S. Z. 2010. A climatic basis for
microrefugia: The influence of terrain on
climate. Global Change Biology
5
Research approach
Study area:
Great Northern LCC
Landscape
Conservation
Cooperative vision
• Sustain diverse
natural systems
6
Research approach
Study design: Climate space of fire
Longitudinal
gradient:
precipitation
seasonality and
continentality
Latitudinal gradient:
temperature
Batllori et al. 2014. Is US
climatic diversity well
represented within the
existing federal
protection network?
Ecological Applications
Fire perimeter
Fire perimeter
7
Research approach
Study design:
sample fires
• Selected fires across
variation in climate space
Tatoosh 2006
8
Research approach
Fire refugia models
What is the relative
importance of
microclimate and
topographic shelter to
formation of fire
refugia?
9
Research approach
Fire refugia models
Predictors
Microclimate
Catchment
area, aspect, flowpath length, height,
slope
Local
aspect, slope, curvature, relative
morphometry position
Topographic
context
Hybrid (TCI)
topographic convergence index:
catchment area / local slope
Wind shelter
eight wind directions;
500-m radius moving window
10
Research approach
Fire refugia models
• Generalized additive models (GAM)
1.
2.
3.
Binary response (refugia/non-refugia)
Combined model: microclimate variables
Combo + topo context (8 wind shelter variables one at a time)
mgcv
11
Refugia models: Tatoosh
Results: comparison of
frameworks
• Microclimate predictors
important, especially
catchment
• Potential refugia at
Tatoosh were likely to be
formed in areas sheltered
from winds in certain
directions
Importance of Topographic
Context (Wind Shelter)
∆AIC
Combination model + Wind Shelter
Min ∆AIC = 5; Max ∆AIC = 22
12
Refugia models: Tatoosh
Conclusion
• Understanding origins and
functions
• Shifting resources in space/time
Refugia Probability
Tatoosh
Hannah, L. et al. 2014. Fine-grain
modeling of species’ response to
climate change: holdouts, steppingstones, and microrefugia. Trends in
Ecology & Evolution
13
Future work and applications
Management implications
• Fire refugia: a new landscape attribute for planning
activities
• Protecting these features and facilitating their
maintenance as a network of habitats
T Burykin, yEd
14
Thank you!
15