14 - Indirect Effects

Question 1

Example of one species directly affecting another

Answer 1

Predation

Question 2

shorebird nest predation _____ with ____ latitude

The is a benefit of ____

Answer 2

decrease with increasing latitude

migration

Question 3

define exploitative competition

Answer 3

2 competitors negatively affect each other even if they don’t come in contact
There is a basis for conflict

Question 4

example of exploitative competition

Answer 4

red crossbill and red squirrel compete for pine cones and negatively affect each other

Question 5

define apparent competition

Answer 5

species that share predators may negatively affect each other (indirectly)

Question 6

List some types of indirect interactions

Answer 6

competitive mutualism
food chain mutualism
indirect mutualism

Question 7

briefly describe the trophic cascade that took place in yellowstone NP

Answer 7

gray wolves reintroduced

elk foraging patterns changed

modified forest structure

Question 8

What are the two drivers of indirect effects?

Answer 8

density-mediated

trait-mediated

Question 9

which drivers were responsible in yellowstone wolves?

Answer 9

both behaviourally-mediated and density mediated

Question 10

for many arctic-nesting birds, nest predation varies with ____

Answer 10

lemming abundance

Question 11

what caused the exponential increase of lesser snow geese?

Answer 11

increase of food availability in winter (agricultural)

Question 12

what are the implications fo Salicornia?

Answer 12

its a salt-tolerant plant than indicated degraded and hyper-saline soil

Question 13

Arctic fox have a _____ response to geese.

briefly describe why

Answer 13

functional response

eat more geese when juvenile goose density is higher

Question 14

fox reproduction is _____ to goose density

TF no ____ response

Answer 14

unrelated

numerical

Question 15

why don’t geese produce a numerical response?

Answer 15

bc foxes must feed all year round so its the winter food that limits

Question 16

briefly describe arctic foxes dependency on seals in relation to lemmings

Answer 16

numerical response to marine foods BUT seals don’t matter when lemmings are abundant.

too risky to go out on sea ice so they only do it when they really need to

Question 17

northern borders of animal distributions are often determined by ?
TF what should happen with CC?

Answer 17

temperatures

densities should increase with warming temperatures

Question 18

southern borders of Arctic animals are determine by what? how do these boundaries differ?

Answer 18

S boundary determined by predators, not temperature!!

Question 19

list roles of foxes in an arctic food web

Answer 19

predation pressure on birds/rodents
ecosystem engineers redistribute nutrients
-increase plant productivity and diversity
-benefit lemmings
-change distribution of other consumers