Functional Ecology and Succession (L6)

Question 1

What is Functional Ecology

Answer 1

Operational Functions: how the system operates
- open energy subsystems: exchange matter and energy w/surroundings, energy flows through food chain, producers convert solar radiation to energy
- closed matter subsystems - only exchange energy with surroundings

Support Functions: what the system does to support life
- good measure of health of ecosystem, estimated by species richness

Question 2

What is the Plant CSR Theory

Answer 2

Related plant success to balance of stress and disturbance on the ecosystem

Stress - anything affecting ability to accumulate carbon through photosynthesis (eg. soil compaction, large tress creating shade for smaller trees, drought etc)

Disturbance - anything that damages/destroys the biomass of plants/bacteria(eg. scree slopes; loose rocks fall, toughen roots and destroy plants)

Competition - struggle b/w organisms/species for same resources (has elements of stress and disturbance, eg - large tress creating shade for smaller ones, large roots taking up soil space etc)

**Refer to slides for disturbance chart and practice applying to pictures below **

Question 3

What is the r-K model

Answer 3

• explains how organisms develop survival strategies
• Opportunists species (r) - adapt towards rapid reproduction of offspring in large numbers (eg. weeds)
• Equilibrium species(K) - lower rate of reproduction, larger, better at competing for resources, live longer

Question 4

What is Succession and explain the 5 stages

Answer 4

Succession: The shifting from one ecosystem to another overtime
- early in succession, ecosystems expend large fraction of total energy on growth, later energy used for maintenance, at climax, no more net accumulation (@equilibrium)

Initiation: the starting point, new unoccupied habitat/”bare land” after major disturbance

Primary Succession: development of ecosystem in an environment that previoursly had no life (has pioneer species: die and decompose and enrich soil for other life to grow)

Colonisation: small number of specialized, high stress tolerant plants, low biomass, lack of organic matter and nutrients

Development - colonizing organisms to modify environment and make it favorable for other organisms

Maturation - vegetation cover is dominated by competitive species, stable soil conditions, lots of competitive grasses, bushes and smaller tress, a high range of trophic levels and detrivores present

Climax - stable ecosystem achieved, dominated by large tress with long life cycle, unchanged until next major disturbance