Disturbance: Introduction, with a terrestrial bias

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






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



• 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

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+10 more



• Disturbance was inevitableDisturbance was inevitable• Diversity dependent on Diversity dependent on

recurrent disturbancerecurrent disturbance



• 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

““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


• Academic lineage questionAcademic lineage question• Language requirementsLanguage requirements• Reprint request cardsReprint request cards


• 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

http://www.unc.edu/scholcomdig/whitepapers/peet.pdf

http://www.unc.edu/scholcomdig/whitepapers/peet.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






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)


Space/TimeSpace/Time EventEventMultieventMultievent

PatchPatch

MultipatchMultipatch




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





(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




(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!

• 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





(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)


19931993


0.01

0.05

10.0

0.1

0.5

1.0

5.0

Dis

turb

ance

Inte

rval

/ R

ecov

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Inte

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AB

C

D

F

Eequilibriumor

steady state

stab le,low

variance

stab le,h igh

variance

stab le,low

variance

unstable system ,




Gaps


0.01

0.05

10.0

0.1

0.5

1.0

5.0

Dis

turb

ance

Inte

rval

/ R

ecov

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Inte

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stab le,low

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variance

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unstable system ,





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

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!


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


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


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

Disturbance: Introduction, with a terrestrial bias

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