Succession

Question 1

Succession

Answer 1

gradual change in plant and animal communities following a disturbance

Question 2

3 ways ecological communities can respond to a disturbance

Answer 2

1. Stability = no change
2. Resistance = ability to maintain structure and func.
3. Resilience = ability to recover after disturbance

Question 3

Primary succession

Answer 3

-occurs on newly exposed geological substrates

Question 4

Secondary succession

Answer 4

• follows disturbance that does not destroy all biological material
• much faster
• e.g. abandoned farm land
• e.g. fire, flood, landslide, human clearing

Question 5

Hydrosere succession

Answer 5

-conversion of aquatic environments (plants take over)

Question 6

climax community

Answer 6

-late in succession –> state of stability until next disturbance

Question 7

Early succession

Answer 7

• rapid increase in species richness
• good colonizers (r-select)
• low survival (vulnerable to herbivores)
• not all groups increase in density throughout succession

Question 8

Human disturbance

Answer 8

• biggest impact on communities world-wide
• terrestrial and aquatic
• typically reduce diversity

Question 9

How long does colonization to climax take?

Answer 9

50-500 yrs
-ecological time (shorter than geologic or evolutionary)
-first stages can be seen during lifetime
-

Question 10

Piedmont

Answer 10

-plain rich with nutrients that washed down from Appalachian Mt.s

Question 11

crabgrass, horseweed, ragweed

Answer 11

years 1-2

Question 12

Broomsedge, aster, wild carrot, goldenrod

Answer 12

years 3-5

Question 13

Virginia pine, red cedar, black locust, sumac

Answer 13

years 5-15

Question 14

closed pine forest

Answer 14

years 20-50

Question 15

deciduous hardwoods (red maple and tulip poplar)

Answer 15

years 50-100

Question 16

mixed deciduous forest with oaks, hickories, beech, and tulip poplars

Answer 16

years 100-300

-climax

Question 17

What happened to bird species during Piedmont succession?

Answer 17

• not consistant
• habitat requirements of some species made early stages of succession favorable
• early birds were lost later
• eventually reached climax bird community

Question 18

3 options that early species can do for later species after disturbance

Answer 18

1. facilitate
2. tollerate
3. inhibit

Question 19

example of facilitation

Answer 19

• macroalgae are early species in intertidal zones

- surf grass recruitment depends on their seeds hooking onto macroalgae

Question 20

tolerance

Answer 20

• initial stages of colonization are not limited to pioneer species
• climax community is reached when tolerant species have been exhausted

Question 21

inhibition example (and definition)

Answer 21

• climax community = long lived resistant species

- creosote bushes do allelopathy –> produce chemicals to discourage colonization around it

Question 22

old field secondary succession

Answer 22

• inhibition in early stages

- facilitation in later stages

Question 23

succession in streams

Answer 23

• flash floods wipe out algae and invertebrates
• some invertebrates escape bc they’re in aerial form
• took 2 months for predator population to recover
• algae came back first, then invertebrates

Question 24

diversity in streams

Answer 24

• highly affected by most plentiful species: cryptolabis)
• when they live in water, diversity is low
• when they’re aerial, diversity is high

Question 25

biomass accumulation model

Answer 25

• model that says forest ecosystems will go through distinct recovery phases
  1. reorganization
  2. aggregation
  3. transition
  4. steady state

Question 26

reorganization

Answer 26

10-20 yrs

-forest loses biomass and nutrients

Question 27

aggregation

Answer 27

100+ yrs

- ecosystem reaches peak biomass

Question 28

transition

Answer 28

biomass declines from peak

Question 29

steady state

Answer 29

biomass fluctuates around mean

Question 30

Park Grass experiment

Answer 30

• long term study of fertilizer treatment effects
• 150 yrs
• Silverton used composition variability as measure of stability
• although stability is maintained, populations can change substantially –> depends too on resolution of study area

Question 31

Chronosequence

Answer 31

• show long term change in ecosystem
• e.g. hawaiin islands, glacier bay, or krakatau
• patterns of nutrient dispersion change

Question 32

Krakatau

Answer 32

• primary succession
• explosion killed everything!
• succession began with algae and insects (arthropods)
• of the 53 plants: 32 (60%) from ocean currents, 17 (32%) from wind, 4 (7%) from fruit eating animals or man