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Flashcards in Succession Deck (68)
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1
Q

What is succession central to

A

Ecology as evolution is to biology

2
Q

What is succession

A

Species change over time (turnover)

3
Q

What effect does disturbance have on succession

A

It is started directed and redirected by it. Climate events, landuse change, conversion of rainforests etc

4
Q

What is the incorrect thought about succession

A

It is thought to progress towards climax but in reality it is complex and multidirectional

5
Q

What are the types of succession

A

Primary succession

Secondary succession

6
Q

What is primary succession

A

From sterile beginnings with no existing communities

7
Q

Example of primary succession

A

Volcanoes

Glaciers

8
Q

Facts about volcanoes

A

3000 active ones.

60-70 erupt annually affecting 500 million people.

9
Q

Facts about glaciers

A

10% earths surface
90% of that in Greenland and Antarctica.
75% of glaciers in retreat - get primary terrain left to look at succession over time

10
Q

How do glaciers create disturbance

A

As they move through landscapes they peel vegetation away, grinding it up and creating a less biodiversity environment but there are microbes under them.

11
Q

How much are glaciers retreating

A

20m per year

12
Q

What is secondary succession

A

On previously colonised land after major disturbance

13
Q

Examples of secondary succession

A
Landslides
Fires
Cultivation
Land abandonment 
Wind throw
14
Q

What are the source of new colonisers in secondary succession

A

Propagules (seeds) organism in the soil, bacteria, fungi, plants that can recover

15
Q

What are the two types of succession processes

A

Autogenic

Allogenic

16
Q

What is autogenic process

A

Species change due to activities organisms themselves - biotic. Competitive and interactions for niches and water

17
Q

What is allogenic process

A

Species change due to external, non biological factors - abiotic. Like climate change and silting of waters

18
Q

What are the two general trends for plant community succession

A

Early successional species

Late successional species

19
Q

Characteristics of early successional species

A
Colonisers ‘ruderals’.
Small and fast growing.
Produce many small seeds for dispersal.
No dormancy requirement.
Often N fixers.
Allocate more energy to reproduction than biomass.
20
Q

Example of N fixers

A

Lichens
Cyanobacteria
Dryas

21
Q

What can colonisers ‘ruderals’ cope with

A

Desecration
Drought
Warm and cold conditions

22
Q

Examples of dormancy periods

A

Some seeds have to be eaten by animals, some have to be frozen to be colonisers

23
Q

What is an advantage in a nutrient limited enivonrkwbt

A

Ability to fix atmospheric nitrogen and turn it to an amino acid

24
Q

Why do early successional species allocate energy to reproduction not biomass

A

To increase chances they have successful next generations

25
Q

What are early successional species classed as

A

R-selected

26
Q

What are late successional species classed as

A

Competitions ‘k-selected’

27
Q

Characteristics of late successional species

A
Large, slow growing (trees)
Dormancy.
Dominate.
Late seeds, animal dispersal sometimes.
Competitive (canopy species)
Allocate energy to biomass not reproduction.
28
Q

What are canopy species

A

Dominate and control light resource. Plants that dominate resources like light has impact on other plants - selection process goes on e.g plants that tolerate lower light.

29
Q

Early advantage in late successional species

A

Big seeds. More energy for seed to produce energy and grow quickly

30
Q

Model for r selected and k selected plants

A

R selected have fast growth rate, high investment in reproduction (Dispersor). High colonisation, low competitive ability.
K selected have slow growth rate, long lived, investment in biomass production (competitor). Low colonisation, high competive ability.

31
Q

What are the patterns of diversity

A

Short term diversity

Longer term diversity

32
Q

What is short term diversity

A

Things changing rapidly e.g mt st Helens with huge pyroxlastuc flow wip e out vegetation on the mountain and created new surface for succession.

33
Q

In Mt St Helens why was there a rapid increase in species after the pyroclasic flow

A

Because the species that are colonising are not the species found at the end of successional process (strategists). Trees and forests are at the end of succession due to their forest cover.

34
Q

What do ribosomes do

A

Concert atmospheric nitrogen for pea and bean plants which can turn co2 into sugar for the bacteria y the roots who are converting the nitrogen

35
Q

What is longer term diversity

A

Limited life historic strategies.
Maximum number of niches and resources.
Competitive exclusion due to resource limitation Means diversity drops over time.
Pathogens and parasites are critical.

36
Q

What is productivity

A

Production of biomass in a community. Relationship eternal productivity and succession over time.

37
Q

Example of longer term diversity

A

Glacier bay, south east Alaska

38
Q

Facts about glacier bays longer term diversity

A

Glacier retreat at a rate of 0.4km.

Creating a plant soil succession chronosequence from 1760 to present day.

39
Q

What are pioneer communities

A

Microbes - bacteria, archaea, fungi
Algae, lichens, liverworts, bryophytes (can dry to nothing or freeze or be saturated and okay)
Exposed environments, can still thrive.

40
Q

How to pioneer species move to colonisers plant species

A

Overtime they bring organic material into the environment.

Protosoil will begin to form once these die, facilitate next stage of succession (10-20 years ice free)

41
Q

What are the stages of succession

A
Pioneer species
Coloniser plant species  
Alder dominated
Alder-Spruce transition
Spruce dominated forest
42
Q

Example of coloniser plant

A

Dryas.

Speed dispersal by wind.

43
Q

When do dryas dominate in the successional stage

A

25 years ice free

44
Q

When do alder dominate in the successional stage

A

75 years ice free

45
Q

What is the alder dominated stage

A

Small shrubs trees, associated with bacteria that can fix nitrogen

46
Q

What is the alder Spruce transition

A

125 years ice free.

Facilitation and inhibition. Excluding some species from the space until you get the dominating species.

47
Q

What is the spruce dominated forest

A

200 years and >300t/ha

48
Q

What are seres

A

Successional stages with characteristic vegetation types of associated biota

49
Q

Case study for successional stages glaciation

A

Rootmos glacier, Austria
Glaciated in 2006 are lichen on rock, biological weathering.
Spatial chronosequence.
Glaciated in 1970 and 1953, 1950.
Alpine meadow, lots of species, diverse but no dominance.
Individual species have characteristic ecological traits.

50
Q

Sand dune case study

A

Cooloola, Australia.

Monocotyledons, graminoids (grasses and sedges), xerophytes (desecration)

51
Q

What does Cooloola look like after 100 years

A

Xerophyte woody shrubs

52
Q

What does Cooloola look like after 200 years

A

Eucalyptus forest

53
Q

What does the volcanic islands in Hawaii look like 100 years after eruption

A

Things can grow in the cracks of the dried lava.

54
Q

What does the volcanic islands in Hawaii look like 300 years after eruption

A

Some trees are growing

55
Q

What does the volcanic islands in Hawaii look like 12,000 years after eruption

A

Lots of treees dominate

56
Q

What is the primary/secondary succession of the slate quarries in Wales

A
Lichens and microbes.
Bryophytes, Moses and liverworts - enough resources for seed germinates. Heterogenous and patchy.
Grasses, sedges and rushes. 
Shrubs - broom and gorse.
Trees - silver birch and holly
57
Q

What are the mechanisms of succession

A

Getting there - colonisation.
Species replacement over time.
Concurrent interactions between them lead to competitive exclusion.

58
Q

Basics of early colonists (pioneers)

A

Light seeds, wind dispersal.
High seed production.
E.g 97u seed, early. For dryas

59
Q

What is the general trend on role of colonisation

A

Successful immigration is lower bc of competitor for secondary succession. High for primary

60
Q

Why are microbial colonists important

A

For first stage of biological weathering and first stage of succession for protosoil e.g black algal crusts in Glacier Bay is tough, flexible, organic mat.

61
Q

How does black algal crusts in Glacier bay help

A

Consolidate surface 1-2cm.
Reduce rain impact/particle movement due to freeze thaw.
N fixers - limiter resource for heterotrophs

62
Q

What are the two species replacement models

A

Inhibition model

Facilitation model

63
Q

Who came up with the species replacement models

A

Connell and Slayter (1977)

64
Q

What is the inhibition model

A

Early arrivals competitively inhibit (light competition)

Spread rapidly and monopolise resources.

65
Q

What is the facilitation model

A

Succession is a series of sequential invasions, each dependant on site amelioration by early colonists.
Species die out since changes in environment suited for later colonists.

66
Q

Example of facilitation

A

N-fixers e.g alder in glacial deposits and lupins on volcanic ash improve soil N status for later colonists

67
Q

What percentage of primary seres has N fixers as dominant vegetation

A

77%

68
Q

In glacier bay how did alders help succession

A

Changes in soil conditions e.g increased soil N making the soil acidify by liberating H+ Ions. Spruce prefer acidic soil so have a competitive advantage.