Community ecology

Question 1

The sequential change in species composition of the community over time

Answer 1

Ecological succession

Question 2

Initial establishment of plant can animal communities on substrates lacking living organism

ex.bare rock, lava

Answer 2

Primary succession

Question 3

Secondly succession

Answer 3

change of an established community
ex. ponds accumulate sediment, leaves, pollen pond gets smaller over time

take holllow pipe and can see each seral stage

Question 4

allogenic succession

Answer 4

abiotic disturbance

Question 5

autogenic succession

Answer 5

biotic disturbance

Question 6

Total biomass in different seral stages following clearcutting gets high then drops to a steady line why?

Answer 6

decomposers take longer to come back after clearcutting

Question 7

After clearcutting how long to reach late seral stages?

Answer 7

Trees takes 100 years all of the forest or ecosystem takes 1000

Trees after Krakatau took 100 years to grow back but yukon took 10,000 years why?

temperature and rainfall

Question 8

Ecological mechanisms for succession

what is stochastic events?

Answer 8

largely unpredictable- who gets there first can be established, most important in early seral stages

Question 9

Ecological mechanisms for succession

What is facilitation?

Answer 9

a species creates condition favourable for succeeding species but not itself

-major process in early stages
-leads to regular shifts in species=assembly rules

ex. predators cannot colonize before prey are present

Question 10

Ecological mechanisms for succession

What is inhibition?

Answer 10

a species inhibits the colonization of subsequent colonists

-allelopathy ex. plant communities and coral reefs
-competitive exclusion- ex. intertidal communities/ competition for space Gigartine and Ulva. Without Ulva gigartina take over beach

Question 11

Ecological mechanisms for succession

What is tolerance?

Answer 11

members of a seral stage are those that co-exist due to the use of different resources

-COMBINES FACILITATION AND INHIBITION into a co-evolution
ex. ghost of competition past

Question 12

Explain the importance of facilitation, stochastic and inhibition int seral stages?

Answer 12

Stochastic and facilitation are most important in early stages with F totally going to low relative importance in late stages. Competitition has more of a effect in late stages

Question 13

Tropic pyramids can be measured 3 ways?

Answer 13

Numbers- ex.protozoa=millions fish=one hundred
Biomass-ex. Oka tree=30 tonnes parasites-100g
Energy -ex. producers-0.4 primary carnivores-0.0016

Question 14

What is a Umbrella or indicator species?

Answer 14

a species used for conservation decisions ex. Grizzly bear, Panda, Owl

Question 15

What is a Dominant species?

Answer 15

a common species with an effect on the community proportional to its biomass ex. trees= loyd of effect but lots of biomass

Question 16

What is a keystone species?

Answer 16

a species with an effect on the community that is disproportion to its biomass ex. sea otter, starfish

biomass low but when removed has a great effect

sea otter eats sea eurchents that would eat all the kelp

Question 17

What is downloading in the Nutrient Cycling?

Answer 17

Rivers with dissolved organic matter, nitrogen and phosphates run into ocean increasing primary production in marine waters

Question 18

Clear and deep mountain lakes would be in low productivity called?

What would increase this?

Answer 18

Oligotrophic
-low nitrogen and phosphorus
- low plankton
-few fish

migration of salmon from oceans brings nutrients proportional to how many die there

Question 19

Do bears follow Optimal foraging with salmon?

Answer 19

No bears eat/kill 65% of salmon not 5%. But most of the predation was on the post-reproductive salmon having a low effect on the species

Question 20

Nitrogen is —-% of earths atmosphere

Answer 20

78

Question 21

Nitrogen is —% of total mass of salmon

Answer 21

3

Question 22

What is the must abundant isotope of nitrogen?

Answer 22

N14 99.3% of total nitrogen

Question 23

Up to —% of the nitrogen in riparian plants is derived from salmon nutrients

Answer 23

80

-very limited salmon in alberta

Question 24

d15N implant species below and above falls.

Answer 24

Higher below the falls where salmon die

Question 25

Salmon constitutes about —% of fall diet of wolves

Answer 25

20

Question 26

Relative to trees salon are a—-species

Answer 26

keystone

Question 27

Relative to bears salmon are —species

Answer 27

dominant

Question 28

Bears are—-species

Answer 28

keystone