M3L2 - Ecological Disturbances

Question 1

Stable environment

Answer 1

Deviations up to a certain point from equilibrium end up returning to equilibrium, or new equilibrium

Question 2

Unstable environment

Answer 2

Small perturbations result in larger shifts and a lack of ability to return to equilibrium

Question 3

Resiliency

Answer 3

• Ability for a system to keep functioning after being subjected to disturbance
• Not always a positive (e.g. Eutrophic lakes)

Question 4

Cumulative effects

Answer 4

• The total effect, including direct and indirect, on a given resource, ecosystem, or community. from all actions taken
• May result from the accumulation of similar effects or interactions between different effects
• May be long lived

Question 5

Analysis of cumulative effects

Answer 5

Analysed by looking at specific resources, ecosystem, or community affected, not by the action that caused them

Question 6

Perspective of cumulative effects

Answer 6

Must be approached from the perspectives of ecosystem resilience, thresholds, carrying capacity, etc

Question 7

Stressor

Answer 7

• Change in environmental conditions that place stress (has an effect)
  on the health and functioning of an organism, population, or ecosystem
• Effects add up from the repeated action of a single stressor
• Impacts also accumulate via interaction between multiple stressors and may change over time

Question 8

Single stressor

Answer 8

Almost never occurs in isolation

Question 9

Multiple stessors

Answer 9

Two or more co occurring or sequential stressors

Question 10

Sources of change that contribute to cumulative environmental effects

Answer 10

• Space crowding
• Time crowding
• Time lags

Question 11

Types of cumulative effects

Answer 11

• Additive
• Synergistic
• Antagonistic
• Reversal

Question 12

Additive cumulative effects

Answer 12

Result from individual stressors (not interacting) whose joint effect equals the sum of the individual effects

Question 13

Synergistic cumulative effects

Answer 13

Interaction where the combined impact of two or more stressors on a response endpoint is larger than the sum of the impacts of the individual stressors

Question 14

Antagonistic cumulative effects

Answer 14

The combined effect of multiple stressors generates a smaller response than expected from the sum of their individual effects

Question 15

Reversal cumulative effects

Answer 15

Occurs when the effects on a response have the opposite direction of the sum of the individual effects of individual stressors