Interspecific Competition

Question 1

Examples of Interspecific Competition…

Answer 1

Phytoplankton complete for P
Plant species for N
Coexistence/Exclusion of competing Salmonid fishes
Diatom and Silicon
Coexisting Competing Birds
Competition between Unrelated Species

Question 2

Salmonid fishes coexistence…

Answer 2

Higher temperatures make two species more aggressive individually, however one less so than the other when together, competition existing spatially

Question 3

Example of spatial competition?

Answer 3

Fishes based on altitudinal zones

Question 4

Realised Niche

Answer 4

The set of conditions actually used by a given animal, considering other present species

Question 5

Fundamental Niche

Answer 5

This is the conditions and resoruces that allow a species to exist isolated from other species

Question 6

Competitive Exclusion Principle

Answer 6

This states that competing species can co-exist if niche differentation occurs, however one elimintates the other besides this

Question 7

When may effective competition exist?

Answer 7

Result of evolution basde on past interspecific competition

Question 8

Problem with past evolution competition idea…

Answer 8

Could have independetly evolved, canot be proven

Question 9

Examples of coexistence without exclusion/differentiation?

Answer 9

Paradox of the plankton

Question 10

Exploitation and Interference Competition

Answer 10

Exploitation is using a particular resource that a another species utilsies, whilst interference indirect(allelpathy)

Question 11

Allelopathy

Answer 11

This is the production of biocemicals that influence reproduction, germination, growth and fecundity of other species, but not the producer.

Question 12

Logistic Equation

Answer 12

dN/dt = rN (K-N)/K modelling increasing population and increasing competition for resource as a result

Question 13

What does multiplying rN by K-N/K do?

Answer 13

Scales growth rate by fraction of available resources, thus population growth rate reduction as it approaches carrying capacity

Question 14

Why is the COC important?

Answer 14

Represents ratio of how many individuals of species 1 equivocates competitive effect of species 2

Question 15

What can logistic equation be used for?

Answer 15

Predict exclusion in an ecosystem

Question 16

What does exclusion predictability depend on?

Answer 16

Densisties, a rarer species may inter-specifically out competed by a more abundant, whilst at equal densities, whomever becomes out of balance.

Question 17

What is a consume-resource models of competition derived?

Answer 17

G growth rate of population/species
M per capita mortality rate
C amount of resource consumed
R net reproductive rate

Question 18

What does the Consumer-resource model show?

Answer 18

Consumer species grow towards maximum rate of g, as R increases, reaching half that rate when amount of resourcei s C

Question 19

What does m1N1 show?

Answer 19

Mortality death rate

Question 20

What complexifies equations in regards to resource?

Answer 20

If they are biotic, they can be self-limiting based on their own logistic equation

Question 21

Derive model of Niche Overlap…

Answer 21

b is input of source R2(resource), indicating its population change
cA2 is how population A affects rate of change of R2, and B the other ecological species

Question 22

What does ca1/ca2 / cb1/cb2 represent?

Answer 22

Degree each species specialises on the two resources, overlap occuring if same prefernce

Question 23

What does competitive exclusion depend on?

Answer 23

Degree of niche overlap and competitive similarity

Question 24

How do environmental changes make comepeitive dynamcis harder?

Answer 24

Some patches only temporarliyu available, sp exclusion may not have time to occur before changes

Question 25

How may environmental changes allow coexistence?

Answer 25

Disturbances create gaps, first coloniser not neccesarilyu most competitive

Question 26

Case study of competition coexistence…

Answer 26

Four ants occupying individual trees, spatially distinct at finer scales, coexisting within regions, tree disturbance allowing recolonisation, where inferior competitiors dominante reclonisation

Question 27

Example of apparent competition?

Answer 27

Gastropods in Santa Catalina island: three gastropod species, bivalves dominaned by clam, all predated by lobster, octopus and whelk, density determines who’s predated

Question 28

Squirrelpox as an example of apparent comp?

Answer 28

Red and grey squirrels in UK

Question 29

What is an example of competitve release?

Answer 29

Ocelots smaller than jaguars and pumas, consume smaller prey, however absence of prey, character displacement

Question 30

Natural Experiments…

Answer 30

Clover ground coverage of 48% whilst grass 96%, clover alone only 40% and grass alone only 5%