Interspecific Competition Flashcards
Examples of Interspecific Competition…
Phytoplankton complete for P
Plant species for N
Coexistence/Exclusion of competing Salmonid fishes
Diatom and Silicon
Coexisting Competing Birds
Competition between Unrelated Species
Salmonid fishes coexistence…
Higher temperatures make two species more aggressive individually, however one less so than the other when together, competition existing spatially
Example of spatial competition?
Fishes based on altitudinal zones
Realised Niche
The set of conditions actually used by a given animal, considering other present species
Fundamental Niche
This is the conditions and resoruces that allow a species to exist isolated from other species
Competitive Exclusion Principle
This states that competing species can co-exist if niche differentation occurs, however one elimintates the other besides this
When may effective competition exist?
Result of evolution basde on past interspecific competition
Problem with past evolution competition idea…
Could have independetly evolved, canot be proven
Examples of coexistence without exclusion/differentiation?
Paradox of the plankton
Exploitation and Interference Competition
Exploitation is using a particular resource that a another species utilsies, whilst interference indirect(allelpathy)
Allelopathy
This is the production of biocemicals that influence reproduction, germination, growth and fecundity of other species, but not the producer.
Logistic Equation
dN/dt = rN (K-N)/K modelling increasing population and increasing competition for resource as a result
What does multiplying rN by K-N/K do?
Scales growth rate by fraction of available resources, thus population growth rate reduction as it approaches carrying capacity
Why is the COC important?
Represents ratio of how many individuals of species 1 equivocates competitive effect of species 2
What can logistic equation be used for?
Predict exclusion in an ecosystem
What does exclusion predictability depend on?
Densisties, a rarer species may inter-specifically out competed by a more abundant, whilst at equal densities, whomever becomes out of balance.
What is a consume-resource models of competition derived?
G growth rate of population/species
M per capita mortality rate
C amount of resource consumed
R net reproductive rate
What does the Consumer-resource model show?
Consumer species grow towards maximum rate of g, as R increases, reaching half that rate when amount of resourcei s C
What does m1N1 show?
Mortality death rate
What complexifies equations in regards to resource?
If they are biotic, they can be self-limiting based on their own logistic equation
Derive model of Niche Overlap…
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
What does ca1/ca2 / cb1/cb2 represent?
Degree each species specialises on the two resources, overlap occuring if same prefernce
What does competitive exclusion depend on?
Degree of niche overlap and competitive similarity
How do environmental changes make comepeitive dynamcis harder?
Some patches only temporarliyu available, sp exclusion may not have time to occur before changes
How may environmental changes allow coexistence?
Disturbances create gaps, first coloniser not neccesarilyu most competitive
Case study of competition coexistence…
Four ants occupying individual trees, spatially distinct at finer scales, coexisting within regions, tree disturbance allowing recolonisation, where inferior competitiors dominante reclonisation
Example of apparent competition?
Gastropods in Santa Catalina island: three gastropod species, bivalves dominaned by clam, all predated by lobster, octopus and whelk, density determines who’s predated
Squirrelpox as an example of apparent comp?
Red and grey squirrels in UK
What is an example of competitve release?
Ocelots smaller than jaguars and pumas, consume smaller prey, however absence of prey, character displacement
Natural Experiments…
Clover ground coverage of 48% whilst grass 96%, clover alone only 40% and grass alone only 5%
