Post on 24-Jan-2016
description
Fire severity and succession: spatial and temporal patterns and
implications for herbivores
Fire severity Implications for herbivores
Patterns of vegetation dominance in the second
decade of succession
Carbon loss Permafrost thaw
Post-fire soil moisture and temperature
Resprouting potential / seed availabilityPost-fire seedling recruitment and establishment
Post-fire residual organic layer depth as a metric of fire severity
Shallow organic layer = high severityDeep organic layer = low severity
Mature black spruce
Low severity
burn
High severityburn
Time
Time
Seedling recruitmentand establishment phase
(Johnstone and Kasischke 2005)
Black spruce self replacement
Persistent deciduous canopy presence?
STUDY SITES 1987 Granite Creek Burn- GC87 1994 Hajdukovich Creek Burn- HC94 1999 Donnelly Flats burn- DF99
1990 Tok burn – TK90
OL depth >8cm
Study sites in 1994 Hajdukovich Creek burn
OL depth 4-8 cm
OL depth 0-4 cm
Aspen
Stem density decreased by 60 %
Biomass per unit area increased ~2 fold
Average individual biomass increased ~ 3 fold
Changes in stand density and biomassfrom 8 yrs to 14 yrs post-fire
Stem density was unchanged
Biomass per unit area increased 40 fold
Average individual biomass increased ~ 30 fold
Spruce
Fire severity effects on species recruitment and establishment patterns are persistent
Shenoy et al. 2011, FEM 261, pp 381-90
Fire severity- species composition relationships across multiple burns
Divergent successional trajectories are developing at two ends of the fire severity spectrum
Shenoy et al .2011
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Aspen
Growth rates of black spruce and aspen in low versus high severity sites (HC94 burn)
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4-8cm
>8cm
Biom
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(g m
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Organic layer depth
Willow biomass
OL depth < 1 cm
Low severity High severity
OL depth ~14 cm
Persistent shift in forest composition
Rachel Lord thesis 2008
Forage availability in HC94 burn
Density of forage species(aspen, willow, birch)
Browse production
Browse removal per ha (x6)
In high severity sites:
Browsing pressure was high throughout HC94 burn
Adapted from Paragi and Kellie 2008 ADFG
Browse production and removal in HC94 burn
Kalin Kellie (ADFG) personal communication
High moose densities in the HC94 burn
Densest moose populations (within GMU 20D) in areas that burned 11-30 years ago Maier et al. 2005, CJFR Vol.35 pp2233-2243
Implications of variation in fire severity for herbivores
FIRE
Fire severity Deciduous: coniferousbiomass
Forage availability
Nutrition Moose populationdensity
Site architecture Forage accessibility
Hunter success
Growth rates of aspen and spruce
Thank you!Knut KiellandJill JohnstoneEric KasischkeRoger Ruess
Field work:Kirsten BarrettMatt BorrCameron CarrollBen CookCassidy PhillipsAdrian Rocha
Thank you!