EE19 Flashcards
What is succession?
a sequence of biological changes in which one group of plant and animal is replaced by another.
What are the 3 hypothesis for driving succession?
-Facilitation
-Inhibition
-Idosyncratic (peculiar/odd)
May differ in the importance in primary vs. secondary structures, in one kind of primary vs. another, for different species in the same succession.
What is Facilitation succession?
Relay floristics, species a paves way for b which paves way for c etc. important for primary succesion eg. lichens-mosses. little evidence in secondary
What is inhibition succession?
the opposite of facilitiation.
A stops B establishing.
B can only invade if A suffers a set back.
- seen in sand dune succession
Give an example of a case study of primary succession.
Glacial Moraine succesion.
- galcial moraine in SE alsak
- clear chronosequence contained in one ecosystem from the retreat of a glacier
Where could primary succession take place?
Lava GlacialRetreats Sea Bed exposure Sand dune rock fall *No soil, lots of sun, few nutrients, typically poor water holding.
What happens after soil formation in primary succession?
nutrient capture, especially N, organic buildup
leads to increased diversity of plant life, increased plant height, good competitors for water and nutrients are replaced by good competitors for light.
What is the typical sequence of primary succession?
lichen moss grass shrubs trees
What is secondary succession?
well developed soil already exists. tree fall (gap dynamic), fire, land slide etc
What is a seral stage?
intermediate stage found in succesion to climax community
often grass land.
prevented from development by fires, grazing etc.
What is Tilmens argument of resource ratios?
Good competitors are those that reduce resource supply to the lowest level.
What is the relationship between colonizing and competing abilities?
trade off
best competitors are worst colonizers
What is initial floristic competition?
species that get there first persist.
fast growing colonists come to dominance eg. grasses.
slower growing species only come to dominance once they have over topped rapid growers.
What is a chronosequence?
series of set forested sites that share similar attributes but are different ages
What is the Pidemont Plateu?
Fertile agricultural region of the states
rolling terrain and long history of settelmetns
following abandonment agricultural land proceeds to old field and ultimately hardwood forest
What are the two approaches to studying vegetation change?
repeated observation of permanent plots over time
observation of different aged plots over time - chronosequence.
*latter easier, former best
