6.5.5 succession

Question 1

define climax community

Answer 1

final stable community that exists after the process of succession has occurred

Question 2

define deflected succession

Answer 2

happens when succession is stopped or interfered with (eg. grazing, lawn mowed)

Question 3

define pioneer species

Answer 3

species that begins process of succession, often colonising an area as first living things there

Question 4

define succession

Answer 4

progressive change in community of organisms over time

Question 5

steps of how succession happens

Answer 5

1. algae & lichens begin to live on bare rock = pioneer community
2. erosion of rock & build-up of dead/rotting organic material produce enough soil for larger plants like mosses/ferns to grow = replace/succeed algae & lichens
3. larger plants succeed these smaller plants until a final, stable community is reached = climax community

Question 6

where does secondary succession take place

Answer 6

on a previously colonised but disturbed/damaged habitat

Question 7

which habitat displays all stages of succession in the same place at the same time

Answer 7

sand dunes

Question 8

stages of succession of sand dunes

Answer 8

1. pioneer species (eg. sea rocket, prickly sandwort) colonise the sand just above the high water mark - can tolerate being sprayed with salty water, lack of fresh water & unstable sand
2. wind-blown sand builds up around base of these plants, forming mini sand dune
   - as plants die/decay, nutrients accumulate in this mini dune
   - as dune gets bigger, plants (eg. sandwort, sea couch grass) colonise it
   - see couch grass has underground stems = helps stabilise sand
3. more stability & accumulation of nutrients allows plants (eg. sea spurge, marram grass) start to grow
   - marram grass shoots trap wind-blown sand, & as sand accumulates the roots grow taller = traps more sand
4. as sand dune & nutrients build up, other plants colonise sand
   - many are leguminous (eg. hare’s foot clover, bird’s-foot trefoil) which convert nitrogen to nitrate
   - with nitrate available, more species colonise dunes (eg. sand fescue, viper’s bugloss) which stabilise them further

Question 9

what will the sand dunes community eventually develop into

Answer 9

grassland, and then woodland

Question 10

sub-climax community as a result of deflected succession

Answer 10

plagioclimax

Question 11

ways succession can be deflected

Answer 11

• grazing
• burning
• application of fertiliser
• application of herbicide
• exposure to excessive amounts of wind