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Flashcards in Succession Deck (32)
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1

Succession

gradual change in plant and animal communities following a disturbance

2

3 ways ecological communities can respond to a disturbance

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

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Primary succession

-occurs on newly exposed geological substrates

4

Secondary succession

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

5

Hydrosere succession

-conversion of aquatic environments (plants take over)

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climax community

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

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Early succession

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

8

Human disturbance

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

9

How long does colonization to climax take?

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

10

Piedmont

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

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crabgrass, horseweed, ragweed

years 1-2

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Broomsedge, aster, wild carrot, goldenrod

years 3-5

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Virginia pine, red cedar, black locust, sumac

years 5-15

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closed pine forest

years 20-50

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deciduous hardwoods (red maple and tulip poplar)

years 50-100

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

years 100-300
-climax

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What happened to bird species during Piedmont succession?

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

18

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

1. facilitate
2. tollerate
3. inhibit

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example of facilitation

- macroalgae are early species in intertidal zones
-surf grass recruitment depends on their seeds hooking onto macroalgae

20

tolerance

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

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inhibition example (and definition)

-climax community = long lived resistant species
- creosote bushes do allelopathy --> produce chemicals to discourage colonization around it

22

old field secondary succession

- inhibition in early stages
-facilitation in later stages

23

succession in streams

-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

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diversity in streams

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

25

biomass accumulation model

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

26

reorganization

10-20 yrs
-forest loses biomass and nutrients

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aggregation

100+ yrs
- ecosystem reaches peak biomass

28

transition

biomass declines from peak

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steady state

biomass fluctuates around mean

30

Park Grass experiment

-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