Ecosystem Resistance and Resilience

Considerable amount of literature Considerable amount of literature supports idea that resilience is supports idea that resilience is

important for ecosystem restorationimportant for ecosystem restoration

Lesson 4Lesson 4

Presentation 1Presentation 1

Rank the following species for protection Score 6 for 1Score 6 for 1stst priority priority Score 1 for last priorityScore 1 for last priority

Lemon shark

Jupiter Charter tours

WWF

Giant Panda

Massassauga Rattlesnake

Bebb’s willow

Sea OtterGorilla

Nat. Geog. US Nat Parks

COSEWIC

Unive Manitoba

Outline

Definition of ecosystem resistance and Definition of ecosystem resistance and resilienceresilience

Use of these terms to evaluate natural and Use of these terms to evaluate natural and human events/activitieshuman events/activities

Ecosystem managementEcosystem management

Ecosystem Resistance

Ability to resist change due to external Ability to resist change due to external eventevent

Rubber band analogy: How much force Rubber band analogy: How much force needed to stretch the bandneeded to stretch the band

Ecosystem Resilience

Resistance to disturbance and speed of Resistance to disturbance and speed of return to equilibrium statereturn to equilibrium state

I.e. ability to “bounce back”I.e. ability to “bounce back” ““Degree, manner, and speed of recovery of Degree, manner, and speed of recovery of

structure, composition and function of the structure, composition and function of the original ecosystem after disturbance”original ecosystem after disturbance”

Rubber band: How quickly band returns to Rubber band: How quickly band returns to initial shapeinitial shape

How resilient?

Resilience dependent on:Resilience dependent on: Type, intensity and frequency of eventType, intensity and frequency of event Site factorsSite factors Adaptation of life formsAdaptation of life forms

Important!

Name some natural events that cause changes in ecosystems

Wind eventsWind events FireFire Rain/stormsRain/storms Floods/landslidesFloods/landslides Ice/snowIce/snow Insects/DiseasesInsects/Diseases AgeAge Earthquakes/Volcanoes/MeteorsEarthquakes/Volcanoes/Meteors

Terrestrial example

White pine forest

Tree speciesTree species White pine, red pine, white spruce, White pine, red pine, white spruce,

balsam fir, aspen, white birchbalsam fir, aspen, white birch PlantsPlants

Hazel, raspberries, dogwoodHazel, raspberries, dogwood

Adaptations of pines to fireAdaptations of pines to fire

thick barkthick bark

crowns crowns high high above the above the forest forest floorfloor

roots deep roots deep in soilin soil

seeds seeds do not do not storestore

High resistance

Moderate resilience

Adaptations of white birch and aspen

Low resistance but high resilience

Trees killed

Resprout or sucker

High/frequent seed production

Light seed

Adaptations of Balsam fir & W. Spruce Thin bark, crowns lowThin bark, crowns low Seed not storedSeed not stored Balsam: Low resistance Balsam: Low resistance

and resilienceand resilience White spruce: Less White spruce: Less

flammable barkflammable bark

Results after fire

Large pine trees more likely to liveLarge pine trees more likely to live Some trees die (name species)Some trees die (name species) Some plants dieSome plants die Some duff burned: nutrient flushSome duff burned: nutrient flush Require live trees to reproduce pineRequire live trees to reproduce pine Seed dropped after fire likely to growSeed dropped after fire likely to grow

Compare with historic logging

Large conifers (pine& spruce) targeted for Large conifers (pine& spruce) targeted for removalremoval

Balsam fir & white birch leftBalsam fir & white birch left Result:Result:

Less pine and spruce in new standsLess pine and spruce in new stands More low quality stemsMore low quality stems Less profit & jobsLess profit & jobs Increase in insect & disease damageIncrease in insect & disease damage

Low resistance and resilience for pine and spruce

Insect and disease of white pinewhite pine blister rustwhite pine blister rust

white pine weevilwhite pine weevil

white pinewhite pine: less pest : less pest damage in partial shade and damage in partial shade and with structure of natural with structure of natural forestforest

Alien species

Native species

Current practices

• retain large seed bearing treesretain large seed bearing trees• thin from belowthin from below• retain veteran treesretain veteran trees• control competitioncontrol competition• retain down woody debris, retain down woody debris,

mast and cavity treesmast and cavity trees• genetic diversitygenetic diversity

How are current practices implemented? Crown Forest Sustainability Act and Crown Forest Sustainability Act and

Environmental Assessment Declaration Environmental Assessment Declaration OrderOrder

Guides that describe standards of practiceGuides that describe standards of practice Training and certificationTraining and certification What else is required for you to know if this What else is required for you to know if this

system is working/being applied correctly?system is working/being applied correctly?

Ecosystem management or emulation forestry The new practices are an example of stand The new practices are an example of stand

level ecosystem management or emulation level ecosystem management or emulation forestryforestry

Try to manage human activities to more Try to manage human activities to more closely match those of natureclosely match those of nature

RATHER THANRATHER THAN Try to manage ecosystemsTry to manage ecosystems

Note: Source of Problem

What is important for ecosystem restoration What is important for ecosystem restoration is what we leave behindis what we leave behind

What is important for economics is what we What is important for economics is what we removeremove

QuestionsQuestions