L5 Functional Ecology and Succession Flashcards
What is Functional Ecology
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
2) Support Functions: what the system does to support life
- good measure of health of ecosystem, estimated by species richness
What determines the changes in the structure and species of ecosystems?
Biodiversity is a good measure of the health of an ecosystem.
Estimated by species richness
The potential of an ecosystem to support species depends mainly on intensities of environmental disturbances
What is the Plant CSR Theory
Related plant success to balance of stress and disturbance on the ecosystem
Stress - anything affecting ability to accumulate carbon through photosynthesis (eg. Soil salinity (reduce uptake of water), Phosphate availability, Drought (crop loss))
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 - Crown shyness - large trees creating shade for smaller ones, large roots taking up soil space, DSV - dog strangling-vine)
**Refer to slides for disturbance chart and practice applying to pictures below. **
What is the r-K model
- 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
What is Succession and explain the 5 stages
Succession: The shifting from one ecosystem to another overtime
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
what is the relationship with succession and energy?
Early in succession, ecosystems expend large fraction of total energy on growth; later, energy is used for maintenance. At climax, no more net accumulation of energy ∴ it is at equilibrium)
Primary succession examples
- Retreating glaciers exposing new
ground surface - Human land development
- Meteor impacts
- War zones
