tilman’s resource ratio hypothesis a simple resource based model of population growth lowhigh...
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Tilman’s Resource Ratio Hypothesis
A Simple Resource Based Model of Population Growth
Low High
Growth Rate as a function of resource availability
Mortality rate isindependent of resource levels
A Simple Resource Based Model of Population Growth
Low High
Equilibrium?
resource level
A Simple Resource Based Model of Population Growth
Resources are drawn down to reach a dynamic balance between uptake and release
An equlibrium population size results
A Simple Resource Based Model of Population Growth
?
Below R*, mortality increases releasing more nutrients into the environment, until the equilibrium point is reached
A Simple Resource Based Model of Competition
What Happens with two species?
A Simple Resource Based Model of Competition
B outcompetes A by drawing
resources below R*A
A Simple Resource Based Model of Competition
Interpretation?
Only one species can exist, if there is one limiting resource
Considering more than one limiting
resource
Two Species and Two Resources
Species A wins Species B wins
Resource 1 Resource 2
Who wins overall?
Dynamics with Two Limiting Resources
Population Increases
Population Decreases
A B
Dynamics with Two Limiting Resources
Who wins?
Dynamics with Two Limiting Resources
Who wins?
A B
?
How do resources draw down?
A B
BA
A wins
B wins
Coexistence
Spatial Variability in Resource Ratios
and Productivity Gradients
2 species
4 species
7 species
3 species
Relationship between
resource availability
and diversity
Predator-Prey Interactions
Predator-Prey Interactions:
A Modeling Menagerie
