Succession Flashcards
lichens
starting point of development
mutualistic relationship between a fungus and an alga
primary succession
starts in newly formed habitats
process of colonisation
start of primary succession
bare rock
sand
shingle
open water
pioneer species
first organisms to colonise bare rock
bare rock
extreme conditions
no soil/ water / nutrients/ extreme temperatures
pioneer phase- colonisation
pioneer species colonise bare rock
ps break up rock surface
build up of organic material as they die, combines with rock fragments to make soil
end of pioneer phase
start of soil
change of conditions allows other species to grow eg. wind-blown moss spores
succession after colonisation
soil builds up and able to hold water
shallow rooted plant species can germinate
conditions continue improving- deeper rooted plants can colonise
competition works
competition in succession
tall plants outcompete pioneer species
replace these species
climax community
stable, final community is reached
- may be one or several dominant species
- community is complex
- remains unchanged unless conditions in habitat change
pioneer plants sand dunes
xeromorphic/ xerophytic features + tolerant of salt spray
underground stem systems to stabilise them
grow faster when buried by sand
small mini-dunes accumulate around stems
second colonisers sand dunes
often nitrogen fixers
cover dune surface
limit wind erosion
secondary succession
bare soil where community has been cleared
organic matter/ mineral content of soil is high
likely plenty of light
unlikely harsh abiotic conditions
characteristic of pioneer species in secondary succession
small
abundant seed production
wind dispersed seeds
fast germination and growth
deflected succession
human intervention prevents succession from running its course
stable but NOT climax community
