complex adaptive systems

charctestics of ecossytems that are CAS

• system with many parts

• interactivity - interdependent, feedbacks

• emergent properties/synergy - whole is greater than parts

• bottom up self organization

• adaptive,evolving-constantly reacting

• system memeory

• fuzzy, open boundaries

what does it mean for ecosystme to have system memeory as CAS

if faced with severe distrubances

what happens in new stand is similar to old stand

• legacies as system memory

feedbacks are key to…..

self organization in terrestrial ecosystems

positive feedback loops

outcome of something happening make it more likley that thing will happen

• can go crazy/ unstable

negative feedback loops

outcome of somting happeing make it less liley that thing will happen

• self regulating and stablizes things

which type of feedback loop is more common in natural ecosystems

negative

• acts a self regulating mecansism and stablizes things in response to disturbances

charcterstics of CAS

• contagion

• unpredicable

• modularity

• redundancy

• resilence

contagion of CAS

easy to spread due to interconnection

• genes, water

modularity of CAS

some parts are more intraconnected than interconnected

• ex. above and below ground foodwebs

unpredictable of CAS

interactions are non linear and threshold effects

• response is variable overtime and can hangle small changes then once too many = big effect

redundancy of CAS

one function can be carried out by multiple components

• other organisms compensate so no net effects if one dies

resiliency of CAS

can recover from disturbance and return to/close to og state

equllbirum vs complexity perspective in forest dynamics

Equllibrium

• pathway to stability is predictable

• distrubance seen as a reset of succession

complexity

• constantly balancing reorganization, conservation, growth and release

eqquilibrium perspective

• cliamte esable at time scales

• after disturbance, ecos follow predicatble path to climax state

• zonal soils and plant communites best reflect regional climate

complexity perspecitve

• climate vary over short and long time scales

• disturbance and recover are ONGOING PROCESSES

• both ecosystems and soils change over time