Transcript Ecological Effects of Fire - School of Forest Resources

Plan for Today (2/25/11)
► Weekly
meteorologist Derek
Jones
► Lecture:
 Fire effects on
wildlife, intro.
 Guest lecture, Louise
Venne- fire effects
on wading birds in
the Everglades
► Lab:
 Burn at ACMF?
Wildlife and Fire
Fire Ecology and Management, 2011
An introduction
Adapted from Deborah Kennard
Ecological Effects of Fire
Basic Premises
1.
2.
3.
4.
All ecosystems change over time
Fire is neither innately good nor bad; it
is just an agent of change
Human perception of whether it is good
or bad depends on resource objectives
Do people think fire is good for wildlife?
Even Smokey’s (and his friends’) perceptions vary
Light
Fire’s Effects on Wildlife
Most animal species respond predictably to the passage of fire,
although the responses vary among species. Some flee, seek
refuge, or rescue young. Other species are attracted to burning
areas (forage during fires or feed on charcoal and ash after fires).
Effects on Animals:
General Principles
► Many
North American species have
evolved in fire environments
► Mortality levels are generally low
► Effects on cover and food sources
 Substantial and generally positive
 Vary across the landscape
► Effects
on individuals may be substantially
different than effects on populations
Are all fires created equal?
► Fire
regime characteristics dictate fire effects on
wildlife
► What are the fire regime components?
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Type
Season
Area burned/ extent
Intensity
Severity
Frequency
Synergy
Effects of Animals on fires:
General Principles
► Fires
may be:
 Lower intensity or
less frequent
► reduced
by grazing
 Increased intensity
or severity
► by
insect damage
 More heterogeneous
► E.g.
pig damage to
fuel continuity
Terry Clason
Direct Effects on Animals
► Vertebrates
 Mortality: mobility & underground nests
decrease this risk
 Related to size of fire and rate of spread
 Loss of nesting sites and young, but...
 Cavity nesters and insect foragers love
dead trees
 Immediate increase in food source for
predators
► Invertebrates
 Mortality high in burn area for life stages
in litter or on plants
 Rapid invasion by some species may
follow burn
► Species composition changes to
early successional fauna
Indirect Effects on Animals
► Habitat:
► Shelter
components?
is temporarily decreased
► Microclimate is modified
Indirect Effects on Animals
► Food
sources & nutritional
quality increase
 plant species diversity increases
 foliage of new herbaceous
plants and shrub sprouts is
more palatable and higher in
nutrients (N,P) and crude
protein
 seed production of many
species increases
 abundance and diversity of
insects may increase
Indirect Effects on Animals
► Habitat
modifications examples
 Birds
►quail
and turkey prefer more open
conditions
►RCW - regular low intensity fires
kill hardwoods
►scrub jays – periodic fires recreate
scrub habitat
►Fire bird
Indirect Effects on Animals
► Habitat
modifications - examples
 Large mammals
►deer
benefit from flush of new growth for browse
 Small mammals
►increased
seed production important for food
Direct and indirect effects- soil
microorganisms
1.
2.
3.
Populations decrease
significantly, especially in
upper horizons and duff
Long term effects?
After fire:
a. Black surfaces increase
temperatures
b. Run-off, leaching of
nutrients if post-fire rain
c. Competition decreases for
populations that can
respond quickly
Seasonal Effects: Dormant Season
► Increase
number of stems of many
hardwoods, shrubs & grass
► Generally don’t kill large diameter
hardwoods (e.g. oaks)
► Favor
bird species that prefer shrubby
- hardwood habitats
Seasonal Effects: Early Spring
► Deciduous
damage
hardwoods most susceptible to
 a positive for hardwood control
 a negative for mast production for wildlife
► Can
damage gamebird nests and
brood, but food supplies probably not
a problem, especially with patchy fires
Seasonal Effects: Growing Season
►
If fire conducted during
rainy, humid weather, results
may be more patchy than in
dry weather
 a positive for wildlife
habitat
►
►
 a negative for some other
objectives
Flowering may be stimulated,
but small pines may be
damaged by intense fire
Favors birds that prefer
open woodlands &
grasslands
Effects on Animals
Effects of prescribed burns
► Few
problems if timed to
avoid nesting of birds with
ground nests
► Increase edge effect &
browse
► Little impact on fish unless
streamside vegetation is
burned, or erosion occurs
Example: Yellowstone fires of 1988
► The
stand-replacing &
mixed-severity fires of
1988 in the Greater
Yellowstone Area,
(mostly lodgepole pinedominated forest),
provided opportunities
to study animal
behavior during burns Bison foraging and resting near burning
(1.2 M acres’ worth!) area,
Photo by JeffHenry, courtesy of National Park Service.
Yellowstone National Park.
► Studies
focused on
large mammals,
including bison, elk,
bear, moose, and deer.
• Scientists observed NO large
mammals fleeing the fires, and most
appeared “indifferent” even to
crowning fires
•Bison, elk, and other ungulates
grazed and rested within sight of
flames, often 100 m or less from
burning trees
•“Throughout the summer,
animals continued their casual
grazing patterns, moving to new
locations and for the most part
staying ahead of the fire”
(firefighter on the scene)
Photo by Jim Peaco, courtesy of National Park Service.
Bison grazing in area converted by
stand-replacing fire from shrubdominated to forb- and grassdominated cover.
Yellowstone fires, 1998, cont.
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Direct fire mortality:
 Surveys found that 345 dead elk (of an estimated 40,00050,000), 36 deer, 12 moose, 6 black bears, and 9 bison died
in greater Yellowstone as a direct result of the fires
Delayed mortality:
 Elk mortality was high (up to 4%) in the winter of 1988 to
1989 due to drought in the summer of 1988 and forage loss
on burned winter range
Fire-killed elk became a large source of carcasses for
scavengers: grizzly bears, black bears, coyotes, bald eagles,
golden eagles, etc.
The increased availability of carcasses benefited grizzly bear
populations because drought had reduced other food sources
Increased production of forb foliage and tuberous roots also
benefited grizzly bears
Summary:Wildlife
►
Effects on animals include:
 Direct: Mortality
 Indirect: Habitat changes
Wildlife diversity and numbers increase with a
mosaic of successional stages created by a variety
of fire prescriptions over time
► Desired management effects may be one to several
years post-fire (e.g. Florida panther)
► Best overall effects by:
►
 varying seasons and intervals
of fires
 burning in small units
 increasing patchiness of burns
 Monitoring & adaptive management
Break
Fire Effects on Water
► Effects
depend on:
fire intensity
exposure of mineral soil
soil texture
slope
rate of revegetation
timing and amount of post-fire
precipitation
 fire suppression & rehabilitation activities
 riparian zones/BMPs
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Fire Effects on Water
► Hydrologic
processes may be modified:
 Decreases:
►Rainfall
interception
►Infiltration
 Loss of om => soil structure collapses & bulk density
increases
 Soil porosity decreases
 Raindrop impacts compact soil and seal surface
pores
 Ash & charcoal residues clog soil pores
►Evapotranspiration
Fire Effects on Water
► Hydrologic
processes may be modified:
 Increases:
►snow
accumulation and rate of melting
►soil water storage (making runoff & streamflow
more responsive to subsequent precipitation)
►overland flow/runoff
►surface erosion (& even mass movement)
►sedimentation
►downstream flow
Burned hillslope with high consumption of litter and organic matter resulting from
the Buffalo Creek Fire which burned 4,690 hectares in May 1996 in the
mountains southwest of Denver, Colorado. Photo by John A. Moody
After the Cerro Grande Fire near Los Alamos, NM, channels draining burned areas
have zones of erosion & deposition. The peeled bark indicates the highest level of
water and debris during a flash flood. The view is downstream and the blue
backpack is about 1 meter tall. Photo by John A. Moody
Streamflow after fires of different severities
Fire Effects on Water
► Water
quality may temporarily change:
 Increases:
► sediments
– soil particles & organic detritus
► turbidity
► nutrients
– especially N, C, & bicarbonates of Ca, Mg & K
► water temperature
 Decreases:
► aquatic
habitat
 depends on size of fire
 little evidence of long term habitat deterioration
 Usually within natural range of variation and/or
short-lived effects
Fire Control Effects on Water
► Fire
retardants
 N & P into water
 Some toxicity to fish
► Fire
lines
 Connect water bodies
 Create channels
Effects on Water - Summary
► Cumulative
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effects may include:
changes in stream channel morphology
organic matter food sources for aquatic fauna
amount & timing of peak flows
……
► Properly
planned prescribed burn will generally not
adversely affect either quality or quantity of
ground or surface water in Florida