ECOL Community succession

Question 1

Succession

Answer 1

the change in species composition over time, which often occurs after a disturbance

Question 2

Example of succession

Answer 2

in Costa Rica, much land that was previously used for grazing cattle is now preserved in national parks and reserves this preserved, undisturbed land is now undergoing succession

Question 3

What is a prime example of primary succession?

Answer 3

Mt. Saint Helens
-lava flows destroyed soil in areas close to the dome
-primary succession began to occur in the years after the blast

Question 4

What is primary succession?

Answer 4

occurs when new land is formed or bare rock is exposed, providing a habitat that can be colonized for the first time (eg. new rock is formed after volcanic eruption)

Question 5

First to colonize

Answer 5

species with seeds/spores that can disperse long distances and tolerate harsh conditions
-r-selected species
-species that produce many, small seeds/spores which can be distrusted via wind

Question 6

Examples of pioneer species

Answer 6

lichen, moss, grass, grass in sand

Question 7

What makes a habitat suitable for K-selected species?

Answer 7

AFTER r-selected species have established in an area, the conditions of a habitat become less harsh making the habitat colonize able by k-selected species (i.e. it is now within their fundamental niche)

Question 8

What is later to arrive after primary succession?

Answer 8

species with seeds that are dispersed by animals and require deeper soil to grow
-K-selected species
-species that grow to be relatively large
-once their seeds arrive in a location and germinate, they can outcompete r-selected species

Question 9

What is the first to arrive during primary succession and what conditions can they grow under?

Answer 9

-pioneer species
-grow on bare rock
-once they die, their biomass will form new soil layers

Question 10

What happens in primary succession after pioneer species have arrived for a while?

Answer 10

the soil builds and holds more moisture because it is shaded by pioneer species
-pollinators or seed dispersing animals as well as the plants that rely on them (K-selected), begin to arrive

Question 11

Pioneer species in order:

Answer 11

bare rock
lichens
small annual plants & lichen
grasses & perennials

Question 12

Intermediate Species

Answer 12

grasses, shrubs, shade intolerant trees (pines)

Question 13

Climax community

Answer 13

shade-tolerant trees such as oak and hickory

Question 14

Secondary succession

Answer 14

occurs when a community has no plants, but organic soil is still present (i.e. after an intense fire or flood that kills all plants)

Question 15

What is the first to sprout in secondary succession?

Answer 15

species whose seeds and/or roots remained in the soil, and that can grow quickly
-usually pioneer or r-selected species
-have a relatively high growth rate (r)
-annual plants and grasses

Question 16

What is later to sprout in secondary succession?

Answer 16

species with seeds that need shade/wet soils to grow will not be able to survive early in the successional timeline
-usually k-selected species
-once established, they can outcompete r-selected species
-shrubs, pines, oaks, etc.