Succession

Question 1

What processes does succession encompass?

Answer 1

Change in:
-species dominance
-species evenness
-species diversity
-species composition
-soil properties
-nutrient flow

Question 2

Why would a species establish or not?

Answer 2

Dispersal limitation
Niche requirements
Competition
Exploitation
Associated mutualists

Question 3

What is chronosequence?

Answer 3

A series of communities or ecosystems representing a range of ages or times since disturbance

Question 4

How long can succession take after glacial disturbances?

Answer 4

Centuries to millennia

Question 5

What should site conditions for a chronosequence be?

Answer 5

Broadly similar, otherwise, the variability due to factors other than age will confound results

Question 6

Why do we see changes in species composition?

Answer 6

Species have different adaptations that allow them to colonize, compete, and persist

Question 7

How is aspen adapted to fire?

Answer 7

Stems burn in a fire
Underground roots can survive fire
Suckers can sprout fast after fire

Question 8

How are jack pine and balsam fir adapted to fire?

Answer 8

Cones covered in pitch
When pitch burns, cones release seeds

Question 9

How is fireweed adapted to fire?

Answer 9

High survival rate in the soil
Can form rhizomes and resprout after fire

Question 10

How long does primary succession at a glacial bay take?

Answer 10

1500 years

Question 11

How does secondary forest succession take?

Answer 11

200 years

Question 12

How long does succession in intertidal communities take?

Answer 12

1.5 years

Question 13

How long does succession in desert streams take?

Answer 13

Can occur on a scale of weeks

Question 14

What is sedimentation?

Answer 14

The deposition of suspended matter onto lake bottom

Question 15

What ecosystem properties can change during the course of succession?

Answer 15

Biomass
Primary production
Respiration
Nutrient retention

Question 16

What ecosystem changes occur at Glacier Bay?

Answer 16

Increase in soil depth during succession
Proportion of organic and litter horizon increases with succession
Changes driven by biomass

Question 17

What are the 3 models of mechanisms of succession?

Answer 17

Facilitation
Tolerance
Inhibition

Question 18

What is the facilitation model to succession?

Answer 18

Early successional species modify their environment so that it becomes less suitable for them but more suitable for other species found in late-successional stages
Early successional species become locally extinct and late-successional spaces persist

Question 19

What is the tolerance model to succession?

Answer 19

Pioneer species do not facilitate or inhibit other species
Community composition structure only by species dispersal and life-history traits
Climax composed of species that are most tolerant to site conditions and competition

Question 20

What is the inhibition model for succession?

Answer 20

Early colonizers inhibit colonization by later arrivals until they are disturbed