Disturbance:Disturbance:Introduction, with a terrestrial Introduction, with a terrestrial
biasbias
Peter White, Biology/Ecology 255, Sept 9, Peter White, Biology/Ecology 255, Sept 9, 20052005
OutlineOutline
A personal historyA personal history
Definition and significanceDefinition and significance
ImportanceImportance
Search for generalitySearch for generality
DiscussionDiscussion
OutlineOutline
A personal historyA personal history
Definition and significanceDefinition and significance
ImportanceImportance
Search for generalitySearch for generality
DiscussionDiscussion
IDH, niche and neutrality; Large scale IDH, niche and neutrality; Large scale behavior: Criticality, HRV, Resilience; behavior: Criticality, HRV, Resilience; Legacy and History matters; Top-Legacy and History matters; Top-down and bottom-up control and the down and bottom-up control and the Healthy Forest Initiative; Healthy Forest Initiative; Restoration…Restoration…
Dartmouth, 1970sDartmouth, 1970s
William S. CooperWilliam S. CooperESA’s Cooper AwardESA’s Cooper Award
Cooper, W.S. 1926. Cooper, W.S. 1926. The fundamentals of The fundamentals of vegetation change. vegetation change. Ecology 7:391-413.Ecology 7:391-413.
Cowles Cowles
Cowles…Cooper…Cowles…Cooper…
Cowles…Cooper…Buell…Cowles…Cooper…Buell…
Cowles…Cooper…Buell…Reiners…Cowles…Cooper…Buell…Reiners…
Cowles…Cooper…Buell…Reiners…ME!Cowles…Cooper…Buell…Reiners…ME!
Cowles…Cooper…Buell…Reiners…ME!Cowles…Cooper…Buell…Reiners…ME!
W.A.R.
Watt, A.S. 1947.Watt, A.S. 1947.
Pattern and process in Pattern and process in the plant community.the plant community.
Journal of Ecology 35:1-Journal of Ecology 35:1-22.22.
Pattern and process in a forested ecosystemPattern and process in a forested ecosystemPattern and process in cliff ecosystemsPattern and process in cliff ecosystemsPattern and process in mangrove Pattern and process in mangrove
ecosystemsecosystemsPattern and process in neotropical Pattern and process in neotropical
secondary rain forestssecondary rain forestsPattern and process in the dynamics of seed Pattern and process in the dynamics of seed
banksbanksPattern, process, and prediction in aquatic Pattern, process, and prediction in aquatic
ecology.ecology.Spatial pattern and process in plant-Spatial pattern and process in plant-
pathogen interactionspathogen interactionsPattern, process, and predictability: the use Pattern, process, and predictability: the use
of neutral models for landscape analysisof neutral models for landscape analysisLandscape ecology: the effect of pattern on Landscape ecology: the effect of pattern on
process.process.
Watt, A.S. 1923.Watt, A.S. 1923.On the ecology of British On the ecology of British
beechwoods with special beechwoods with special reference to their reference to their regeneration.regeneration.
Journal of Ecology 11:1-48.Journal of Ecology 11:1-48.
The Leopold Report, The Leopold Report, 19631963
Excitements!Excitements!
• Succession did not start from Succession did not start from equally blank slatesequally blank slates
Excitements!Excitements!
• Succession did not start from Succession did not start from equally blank slatesequally blank slates
• Disturbance was inevitableDisturbance was inevitable
27 Cove Trees of Joyce Kilmer Memorial Forest
MaMt
Mf
Lt
Ar
As
Th
Ap
Qr
Cd
Cg
Fa
Af
Ns
Io
Fg
Ba
Bl
Cf
PsAl
Im
Ca
HvTc
Hc
Dv
+10 more
Excitements!Excitements!
• Succession did not start from Succession did not start from equally blank slatesequally blank slates
• Disturbance was inevitableDisturbance was inevitable• Diversity dependent on Diversity dependent on
recurrent disturbancerecurrent disturbance
Excitements!Excitements!
• Succession did not start from Succession did not start from equally blank slatesequally blank slates
• Disturbance was inevitableDisturbance was inevitable• Diversity dependent on Diversity dependent on
recurrent disturbancerecurrent disturbance• Chance and transient dynamicsChance and transient dynamics
““Shakespeare, he’s in the Shakespeare, he’s in the alley”alley”
--Bob Dylan, --Bob Dylan, Stuck Inside of Mobile with the Memphis Stuck Inside of Mobile with the Memphis
Blues Again, Blonde on BlondeBlues Again, Blonde on Blonde
““Shakespeare, he’s in the Shakespeare, he’s in the alley”alley”
--Bob Dylan, --Bob Dylan, Stuck Inside of Mobile with the Memphis Stuck Inside of Mobile with the Memphis
Blues Again, Blonde on BlondeBlues Again, Blonde on Blonde
““Death of The Climax”Death of The Climax”Missouri Botanical Garden, Missouri Botanical Garden,
19781978
Henry Cowles 1899 Lake Michigan Sand Henry Cowles 1899 Lake Michigan Sand DunesDunes
““Death of The Climax”Death of The Climax”Missouri Botanical Garden, Missouri Botanical Garden,
19781978
b. Chicago, b. Chicago, Illinois, Illinois, 18991899
d. d. St.Louis, St.Louis, Missouri, Missouri, 19781978
ClimaClimaxx
Changes…Changes…
• Academic lineage questionAcademic lineage question• Language requirementsLanguage requirements
Changes…Changes…
• Academic lineage questionAcademic lineage question• Language requirementsLanguage requirements• Reprint request cardsReprint request cards
Changes…Changes…
• Academic lineage questionAcademic lineage question• Language requirementsLanguage requirements• Reprint request cardsReprint request cards• Nature of the thesisNature of the thesis• New journalsNew journals
Subscriptions to journals and journal Subscriptions to journals and journal loyalty -- we read more now but less in loyalty -- we read more now but less in any one journal, and typically in digital any one journal, and typically in digital format. And, our method of discovery is format. And, our method of discovery is altogether different – Bob Peet altogether different – Bob Peet www.unc.edu/scholcomdig/whitepapers/www.unc.edu/scholcomdig/whitepapers/peet.pdfpeet.pdf
Species response to Species response to disturbance (disturbance (from Vogl from Vogl
19741974))• IncreasersIncreasers• DecreasersDecreasers• InvadersInvaders• RetreatersRetreaters• IntegratorsIntegrators• Neutral speciesNeutral species
Questions for the Questions for the SemesterSemester
• What have we learned?What have we learned?• What generalities can we What generalities can we
make?make?• What are the obstacles to What are the obstacles to
generality?generality?• What are the interesting and What are the interesting and
important questions?important questions?
First announcement:First announcement:
Disturbance and Disturbance and restoration in forest restoration in forest
ecosystemsecosystemsCourse for the PhD-programme in “Biodiversity and Course for the PhD-programme in “Biodiversity and Forestry“, Forestry“, Vårdnäs, Linköping, Feb 13 – 17, 2006.Vårdnäs, Linköping, Feb 13 – 17, 2006.
Course leaders:Course leaders:
Mats Niklasson, Southern Swedish Forest Research Mats Niklasson, Southern Swedish Forest Research Centre,Centre, SLUSLU
Per-Anders Esseen, Ecology & Env Science, UMUPer-Anders Esseen, Ecology & Env Science, UMU
Invited teachers:Invited teachers:
prof Peter White,Biology Univ of North Carolina, USAprof Peter White,Biology Univ of North Carolina, USA
prof Sylvie Gauthier, Canadian Forest Service, Quebecprof Sylvie Gauthier, Canadian Forest Service, Quebec
Lars- Owe Wikars, Entomology SLU UppsalaLars- Owe Wikars, Entomology SLU Uppsala
Lars Östlund, Forest Vegetation Ecology, SLU UmeåLars Östlund, Forest Vegetation Ecology, SLU Umeå
and moreand more
OutlineOutline
A personal historyA personal history
Definition and significanceDefinition and significance
ImportanceImportance
Search for generalitySearch for generality
DiscussionDiscussion
Disturbance definitionsDisturbance definitions
• Absolute: Absolute: – A A discretediscrete event in time that event in time that
disruptsdisrupts ecosystem, community, or ecosystem, community, or population structure and changes population structure and changes resources, substrate availability resources, substrate availability or the physical environment or the physical environment (White & Pickett 1985)(White & Pickett 1985)
– Grime: a loss of biomassGrime: a loss of biomass
Relative Definition:Relative Definition:DisplacementDisplacement
from normal dynamicsfrom normal dynamics• Patch dynamicsPatch dynamics• Quantitative & qualitative Quantitative & qualitative
equilibriumequilibrium• Historic Range of Variation, Historic Range of Variation,
Natural Range of VariabilityNatural Range of Variability• CriticalityCriticality• ResilienceResilience
ImportanceImportance• BiodiversityBiodiversity• Exotic invasionsExotic invasions• Effects on value, healthEffects on value, health• Ecosystem use, harvestEcosystem use, harvest• Climate changeClimate change• Land-use and hazard insuranceLand-use and hazard insurance• Environmental ethics in a Environmental ethics in a
patch dynamic worldpatch dynamic world
The 17 Ten Greatest HitsThe 17 Ten Greatest Hits2000+ Papers2000+ Papers
Obstacles to GeneralityObstacles to Generality
Patch & Multipatch Patch & Multipatch ScalesScales
Patch scale
Multipatch scale
Thinking about Thinking about disturbancedisturbance
SpaceSpace
PatchPatch
MultipatchMultipatch
(Landscape)(Landscape)
Thinking about Thinking about disturbancedisturbance
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch
MultipatchMultipatch
(Landscape)(Landscape)
Thinking about Thinking about disturbancedisturbance
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape)
Thinking about Thinking about disturbancedisturbance
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape)
Thinking about Thinking about disturbancedisturbance
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape) Easiest to study
Thinking about Thinking about disturbancedisturbance
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape) Biodiversity, Sustainability
Thinking about disturbance
#1 Patch-Event Scale
Legacy matters
Empirical detail matters
Specificity matters
Disturbances within Disturbances within one ecosystem varyone ecosystem varyAppalachian Fir ForestAppalachian Fir Forest
A family of successions A family of successions differing in legacy differing in legacy because of because of difference difference in severityin severity
Fire intensity & effects on soils --from Ryan 2002
FIRE SEVERITYFIRE SEVERITY
Organic Soil Depth & Coarse Wood
Long Term Drying
Shor
t Ter
m D
ryin
g &
Win
d
Can
opy
Hei
ght &
Mas
s of
Fin
e Fu
el
Site Factors
Weather Factors
Fir
elin
e In
tens
ityF
irel
ine
Inte
nsity
(Fla
me
Len
gth)
(Fla
me
Len
gth)
Depth of BurnDepth of BurnUnburnedUnburned LightLight ModerateModerate DeepDeep
UnburnedUnburned
LowLow
ModerateModerate
HighHigh
ExtremeExtreme
19
Ground Fire with Total Duff Consumption
Time (hours)0
Tem
pera
ture
(C
)
1100Savannah Grass Fire without Duff Consumption
Time (minutes) 4
Tem
pera
ture
(C
)
325
0
Crown Fire without Duff Consumption
Time (minutes)10 25
Tem
pera
ture
(C
)
0
1100
0 16
Crown Fire with Total Duff Consumption
Time (hours)
Tem
pera
ture
(C
)
1100
Richter et al. 1996
Specificity & structureSpecificity & structure• NoneNone
– Drought, landslide, dune Drought, landslide, dune movement, freeze-thaw, salinity movement, freeze-thaw, salinity incursions, crown fireincursions, crown fire
• Large, dominant individualsLarge, dominant individuals– Ice storm, windIce storm, wind
• Small individualsSmall individuals– Surface fire, flood, falling treesSurface fire, flood, falling trees
Disturbance specificityDisturbance specificity
a A b B
Succession
Disturbance
Disturbance specificity: Disturbance specificity: Setting succession backSetting succession back
a A b B
Succession
Disturbance
Disturbance specificity: Disturbance specificity: Advancing successionAdvancing succession
a A b B
Succession
Disturbance
Disturbance specificity: Disturbance specificity: Holding succession in Holding succession in
checkcheck
a A b B
Succession
Disturbance
Disturbance specificity: Disturbance specificity: Maintaining late Maintaining late
successional speciessuccessional species
a A b B
Succession
Disturbance
Thinking about Thinking about disturbance #2disturbance #2
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape)History matters
Interactions matter
Clark 1996
Disturbance density in time
Disturbance Regime: Disturbance Regime: SynergismsSynergisms
• Feedback between community Feedback between community state & disturbancestate & disturbance
• Feedback between time since Feedback between time since disturbance & the next disturbance & the next disturbancedisturbance
• Disturbance interactionsDisturbance interactions
Disturbances interact:Disturbances interact:history mattershistory matters
+ promote subsequent disturbance+ promote subsequent disturbance- inhibit subsequent disturbance- inhibit subsequent disturbance• Fire-fire (Covington & Moore 1994)Fire-fire (Covington & Moore 1994)• Fire-insect (Flamm et al. 1993)Fire-insect (Flamm et al. 1993)• Fire-grazing (Vinton et al. 1993)Fire-grazing (Vinton et al. 1993)• Wind-fungi-insects (Matlack et al. Wind-fungi-insects (Matlack et al.
1993)1993)• Avalanche-fire-insects (Veblen et Avalanche-fire-insects (Veblen et
al. 1994)al. 1994)
Hardwoods
White pine
% D
amag
e
20 40 Age (yr) 80 100
Hurricane damage increases with Hurricane damage increases with age & is greater in successional pine age & is greater in successional pine stands than hardwoods at any age -- stands than hardwoods at any age -- Foster 1988Foster 1988
Disturbance Regime: Disturbance Regime: SynergismsSynergisms
• Feedback between time since Feedback between time since disturbance & the next disturbance & the next disturbancedisturbance
Suppression decreases frequency Suppression decreases frequency BUT increases severityBUT increases severity
Feedback with time Feedback with time since disturbance: firesince disturbance: fire
From Niklasson & From Niklasson & GranstromGranstrom
Gustafson et al. 2004Gustafson et al. 2004
Management influence on risk of crown fire to towns
FIRE SUPPRESSION DECREASES CROWN FIRE RISK!
Thinking about Thinking about disturbance #3disturbance #3
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape)
• Climate, site drive disturbance regime
• Process creates pattern• Pattern creates process
Disturbance-climate Disturbance-climate relationsrelations
• Regional synchronicityRegional synchronicity– Climate systems & spatial Climate systems & spatial
autocorrelationautocorrelation– Stress on managementStress on management– Violation of independence for otherwise Violation of independence for otherwise
isolated populations that we had hoped isolated populations that we had hoped were independentwere independent
Southern Oscillation & fire --Swetnam & Betancourt Southern Oscillation & fire --Swetnam & Betancourt 19901990
Bekker & Bekker & Taylor 2001Taylor 2001
Rollins et al. 2002 In the S, more
fire on NW, N, NE slopes
In the N, more fire on SW, W slopes
Process creates pattern• + Fire often increases
heterogeneity• - Succession often decreases
heterogeneity
Heterogeneity Higher
Lower
Hi Meadow, CO 4,422 ha
Viveash, NM 11,017 ha
Bobcat Gulch, CO 3,059 ha
High burn
Low/ Unburned
Image from S. Kotliar, USGS
Heterogeneity is important in recovery: distance, size, seed source, legacy
Pattern also creates process
+ Fire spread from more to less flammable stands
- Fire absent from flammable stands because of fire breaks
Islands in boreal forest lakes Bergeron & collaborators
• Isolated from large, high intensity mainland fires
• Lightning ignitions increase as island size, elevation, & isolation increase
• Frequent low intensity fires maintain island populations of Red Pine that could not persist in the mainland crown fire regime
Fuel Connectedness & Fuel Connectedness & FireFire
Cape Canaveral
Duncan & Schmalzer 2004
Connectedness & Fuel Connectedness & Fuel MoistureMoisture
Turner and Romme 1994
*
*
high fuel moisture
e.g., typical spring
*
*
low fuel moisture
e.g. typical late-summer
low flammability
high flammability
burned
* lightning strike
very low fuelmoisture and wind
e.g. 1988
WIN
D
*
*
Pattern & Process
• Pattern controls process at low to medium fire intensities
• Process overwhelms pattern at high fire intensities– Agee 1998
Pattern & Process
• Pattern controls process at low to medium fire intensities
• Process overwhelms pattern at high fire intensities– Agee 1998
• TOP DOWN vs. BOTTOM UP CONTROL– Top Down = Climate– Bottom Up = Fuels
Thinking about Thinking about disturbance #4disturbance #4
Space/TimeSpace/Time EventEventMultieventMultievent
PatchPatch 1. P-E1. P-E 22. . P-MEP-ME
MultipatchMultipatch 3. MP-E3. MP-E 4. MP-ME4. MP-ME
(Landscape)(Landscape)Dynamic equilibrium Historic range of variation
Frequency vs. Frequency vs. Magnitude Magnitude Gaps in Gaps in Japanese Japanese deciduous deciduous forest --forest --Tanaka & Tanaka & Nakashizuka Nakashizuka 19981998
Two definitions of dynamic equilibrium
1. Quantitative equilibrium
%
Time
Two definitions of dynamic equilibrium
2. Qualitative or persistence equilibrium
BOUNDED VARIATION
%
Time
Minimum dynamic area
An area large enough to contain all the patch types and to result in the sustained dynamics of the ecosystem
Minimum dynamic area
An area large enough to contain all the patch types and to result in the sustained dynamics of the ecosystem
Rules of ThumbMaximum disturbance <20% of area in a 250 yr period (Frelich & Lorimer 1991)Maximum Disturbance <50% study area (Johnson 1992)
Shugart’s 1:50 Rule
Stability of Landscape Stability of Landscape Patterns –Patterns –from Turner et al. from Turner et al.
19931993
D isturbance Extent / Landscape Extent0.25 0.50 0.75
0.01
0.05
10.0
0.1
0.5
1.0
5.0
Dis
turb
ance
Inte
rval
/ R
ecov
ery
Inte
rval
AB
C
D
F
Eequilibriumor
steady state
stab le,low
variance
stab le,h igh
variance
stab le,low
variance
unstable system ,
b ifurcation or crash
stab le,very h ighvariance
(Turner et al. 1998)
Stability of Landscape Stability of Landscape Patterns –Patterns –from Turner et al. from Turner et al.
19931993
D isturbance Extent / Landscape Extent0.25 0.50 0.75
0.01
0.05
10.0
0.1
0.5
1.0
5.0
Dis
turb
ance
Inte
rval
/ R
ecov
ery
Inte
rval
AB
C
D
F
Eequilibriumor
steady state
stab le,low
variance
stab le,h igh
variance
stab le,low
variance
unstable system ,
b ifurcation or crash
stab le,very h ighvariance
(Turner et al. 1998)
Gaps
D isturbance Extent / Landscape Extent0.25 0.50 0.75
0.01
0.05
10.0
0.1
0.5
1.0
5.0
Dis
turb
ance
Inte
rval
/ R
ecov
ery
Inte
rval
AB
C
D
F
Eequilibriumor
steady state
stab le,low
variance
stab le,h igh
variance
stab le,low
variance
unstable system ,
b ifurcation or crash
stab le,very h ighvariance
(Turner et al. 1998)
Stability of Landscape Stability of Landscape Patterns –Patterns –from Turner et al. from Turner et al.
19931993
* *
1981 YNP
1988
Pascual & Guichard Pascual & Guichard 20052005
Historic Range of VariationHistoric Range of VariationNatural Range of VariabilityNatural Range of Variability
• Qualitative or persistence Qualitative or persistence equilibriumequilibrium
• Variation--but bounded Variation--but bounded variationvariation
Simulating the Historic Range of Variation
Wimberly et al. 1999Province
Nat Forest
Late Succ Reserve
Single run
HRV in Yellowstone – Tinker et al. 2003
HRV in Yellowstone – Tinker et al. 2003
HRV in Yellowstone – Tinker et al. 2003
Process creates pattern: The oldest age Process creates pattern: The oldest age class increases with landscape size class increases with landscape size -- -- from Johnson et al. 1995from Johnson et al. 1995
Old growth definition varies with scale
The Search for The Search for GeneralityGenerality
Mackey, R.L. and D.J.Currie2001. The diversity-disturbancerelationship: it is generallystrong and peaked? Ecology 82:3479-3492. No!
The Search for The Search for GeneralityGenerality
Obstacles 1: Understanding the Obstacles 1: Understanding the EnvironmentEnvironment
Number of potential factorsNumber of potential factors
Preceding & subsequent Preceding & subsequent environmentenvironment
Heterogeneity within patchesHeterogeneity within patches
The Search for The Search for GeneralityGenerality
Obstacles 2: Understanding Species responseObstacles 2: Understanding Species responseSpecificity to species, structureSpecificity to species, structureLegacy, including landscape heterogeneityLegacy, including landscape heterogeneityContingency Contingency
Ecological timeEcological timeEvolutionary timeEvolutionary time
Patch interactionsPatch interactionsCompensatory changes among competitors, Compensatory changes among competitors,
layers, contingent on trophic structure, layers, contingent on trophic structure, indirect effectsindirect effects
Idiosyncratic species traitsIdiosyncratic species traits
The Search for The Search for GeneralityGenerality
Obstacles 3: MethodsObstacles 3: Methods
Surrogate variablesSurrogate variables
Scale of observation (within or Scale of observation (within or between patches)between patches)
Lack or impossibility of Lack or impossibility of experimentsexperiments
Intermediates to Intermediates to generalitygenerality• Bins of variationBins of variation
– Forest vs. grasslandForest vs. grassland– Crown vs. surface fire regimesCrown vs. surface fire regimes– Biotic vs. physical disturbancesBiotic vs. physical disturbances– Grazing vs. decomposing Grazing vs. decomposing
dominated ecosystemsdominated ecosystems– Supply side vs. competition-Supply side vs. competition-
driven ecosystems driven ecosystems
Approaches to Approaches to generalitygenerality
• Patch scale: resources & Patch scale: resources & environmentenvironment
• Multipatch scale: dynamic Multipatch scale: dynamic equilibrium, sustainability equilibrium, sustainability
• Species strategies: trait Species strategies: trait dispersiondispersion– Evolutionary contingencyEvolutionary contingency– Ecological contingencyEcological contingency
• Normalization of spatial & Normalization of spatial & temporal axestemporal axes
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