7. Communities are composed of interacting species

Question 1

What is a biological community?

Answer 1

Group of populations of different species living in the same area

Question 2

Who am I?

I study the interactions between different species

Answer 2

Community ecology

Question 3

What are the 3 big interactions?

Answer 3

1. Predation
2. Competition
3. Mutualism

Question 4

Who are the winners and losers of predation?

Answer 4

Winner: Predator
Loser: Prey

Question 5

How do you define a predator at the individual level?

Answer 5

Consumes and removes an individual prey

Question 6

How do you define a predator at the population level? (Our focus)

Answer 6

Decreases prey N or decreases prey population growth rate

Question 7

Do predators decrease the density of prey populations?

Answer 7

Often, yes.

Question 8

True or false: Exotic predators often have devastating effects on prey

Answer 8

True

Question 9

Who am I?

To release a predator in order to control the N of prey. Works sometimes, devastating other times.

Answer 9

Biological control

Question 10

Should we cull predators to increase prey populations?

Answer 10

It’s a big debate.
ex: wolves and deers. Wolves are endangered, but not in that area.
You need to think ahead: Will a cull of seals increase cod? Not necessarily. Cods have other predators, which may increase if we reduce seals which will increase cods. Conduct an experiment before choosing.

Question 11

Can harvest and community ecology work together?

Answer 11

yes: Sustainable harvest should be defined within a community/ecosystem context. Don’t harvest a predator and its prey. (See Puffins picture)

Question 12

Who am I?

• Harvested populations live within biological communities
• Harvesting one species has effects on other species
• Optimal yield should be calculated within a community context

a) Sustainability I
b) Sustainability II
c) Sustainability III

Answer 12

b) Sustainability II

Question 13

How can one harvest in a community context?

Answer 13

MSY Theory
(See Graph)
Joint Harvest recommended by the naïve population ecologist
Find the sustainable harvest of both species

Question 14

Fill in the blank: Implications of community ecology: predation

1. Predators typically keep prey populations ___, but not always
2. Depends on the strength of the _____ _______.
3. Perform an _____ or _____ before hulling predators
4. Should evaluate the _____ of harvest on the entire community.
5. Harvesting many species in a community is _______.
6. Applying ___ theory just to one species is complicated enough.
7. Should we harvest the most ______ and leave the others?
8. Sustainability II: Harvest should be evaluated within a _____ _____.

Answer 14

1. Low
2. Community interactions
3. Experiment, simulation
4. Effect
5. Problematic
6. MSY
7. Valuable
8. Community context