Ecological Succession

Question 1

what are the two main types of ecological succession?

Answer 1

primary and secondary succession

Question 2

what is a keystone species?

Answer 2

a species in an ecosystem whose activities have a particularly significant role in determining community structure

Question 3

what do pioneer members of an early successional species commonly do?

Answer 3

they commonly move into unoccupied habitat and over time adapt to its particular conditions, which may result in the origin of a new species

Question 4

what is the effect of succession in a disturbed ecosystem?

Answer 4

it will affect the total biomass, species richness, and net productivity over time

Question 5

what is ecological succession?

Answer 5

a series of predictable stages of growth that a forest (or other ecosystem) goes through

Question 6

what is primary succession?

Answer 6

starts from bare rock in an area with no previous soil formation

Question 7

how does primary succession work?

Answer 7

moss and lichen spores carried by the wind grow directly on rocks, breaking them down to form soil (this makes moss and lichen pioneer species along with fungi and microorganisms like bacteria)
moss and lichen are able to grow directly on rock by secreting acids that break down rock and release minerals containing nutrients they need (N/P/K)
the chemical weathering of rocks by moss and lichen combined with organic matter from moss and lichen dying forms initial shallow soil

Question 8

what is secondary succession?

Answer 8

starts form already established soil in an area where a disturbance (fire/tornado/human land clearing) cleared out the majority of plant life

Question 9

how does secondary succession work?

Answer 9

grasses, sedges, wildflowers, and berry bushes have seeds dispersed by wind or animal droppings

Question 10

what characterizes the stages of ecological succession? why?

Answer 10

which types of plant species dominate the ecosystem
different species are adapted to the conditions of the different stages

Question 11

when do pioneer/early succession species appear?

Answer 11

they appear first, when the ground is simply bare rock (primary) or bare soil after a disturbance (secondary)

Question 12

what are the characteristics of pioneer/early succession species?

Answer 12

seeds spread by wind or animals, fast growing, tolerant of shallow soil and full sunlight

Question 13

what are some examples of pioneer species?
what are some examples of early succession species?

Answer 13

pioneer: moss, lichen, bacteria, fungi
early: wildflowers, raspberries, grasses/sedges

Question 14

when do mid-successional species appear?

Answer 14

they appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death

Question 15

what are the characteristics of mid-successional species?

Answer 15

they are relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers, and are sun tolerant

Question 16

when do late successional/climax community species appear?

Answer 16

they appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early and mid successional species

Question 17

what are the characteristics of late successional/climax community species?

Answer 17

they are large, slow-growing trees that are tolerant of shade, and require deep soils for large root networks

Question 18

what are examples of late successional/climax community species?

Answer 18

maples, oaks, other large trees

Question 19

where does primary succession occur? what is an example?

Answer 19

occurs in an area that hasn’t previously been colonized by plants, bare rock such as volcanic rock exposed after glacial retreat

Question 20

where does secondary succession occur?

Answer 20

occurs in an area that already has established soil, but has had most plant life removed by a disturbance

Question 21

how are pioneer species in secondary succession the same and different than pioneer species in primary succession?

Answer 21

they are still wind dispersed seeds of plants that are fast-growing and sun tolerant, but they are grasses/wildflowers/weeds instead of moss/lichen

Question 22

is primary or secondary succession faster? why?

Answer 22

secondary succession because the soil is already established and sometimes even enriched by nutrient-rich ash from fire