barnacle Chthalamus stellatus . Lotka Volterra Competition Alfred J. - - PowerPoint PPT Presentation

barnacle chthalamus stellatus lotka volterra competition
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barnacle Chthalamus stellatus . Lotka Volterra Competition Alfred J. - - PowerPoint PPT Presentation

J. H. Connell, Ecology, 1961. The influence of interspecific competition and other factors on the distribution of the p f f barnacle Chthalamus stellatus . Lotka Volterra Competition Alfred J. Lotka (1880 1949), Vito Volterra (1860


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SLIDE 1
  • J. H. Connell, Ecology, 1961. The influence of interspecific

competition and other factors on the distribution of the p f f barnacle Chthalamus stellatus.

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SLIDE 2

Lotka‐Volterra Competition Alfred J. Lotka (1880 – 1949), Vito Volterra (1860 – 1940) L tk V lt d l (i l di titi ) P it th Lotka‐Volterra models (including competition): Per capita growth rate of any species depends linearly on the densities of other species in the community.

1 1 2 1

1 1 dN N N r N dt K          

1 1 2 2 1 2

1 1 N dt K dN N N r N dt K            

2 2

N dt K  

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SLIDE 3

Isoclines are not necessarily straight lines

from Gilpin & Justice, Nature, 1972

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SLIDE 4

Resource competition David Tilman competition among algae in chemostats

Photo credit Thomas Massie

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SLIDE 5

What are “resources”? Tilman: “A resource is defined as a consumable factor for which increases in its availability lead to increased per capita d ti t th h t l t f it reproductive rates, through at least some range of its

  • availability. … It is through the depression of resource levels

caused by consumption that species compete with each other, and thus that resources may influence the structure of

  • communities. ”

Examples (for plants): Water, light (PAR), nutrients, space (for sessile plants) Temperature is not a resource (why?)

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SLIDE 6

Resource competition, a la Tilman For each resource: Rate of change

  • f resource

= Resource supply ‐ Biotic consumption For each consumer: Per capita rate = Resource‐ dependent ‐ Mortality

  • f change

= dependent reproduction ‐ Mortality

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SLIDE 7

Resource competition, a la Tilman For each resource: Rate of change

  • f resource

= Resource supply ‐ Biotic consumption For each consumer: Per capita rate = Resource‐ dependent ‐ Mortality

  • f change

= dependent reproduction ‐ Mortality