Question

In this scenario, two species are competing and you have the following information to work with:

For Species 1: K1 = 800 For Species 2: K2 = 700 The competitive coefficients are: α12 = 0.6 α21 = 0.95

Q: What do you predict is the competitive outcome, if, given the Scenario 1 information above, you have a starting density where N1 = 10, N2 = 20 ?

Species 1 wins

Species 2 wins

Stable Coexistence

Unstable Coexistence

Q:

What do you predict is the competitive outcome, if, given the Scenario 1 information above, you have a starting density where N1 = 1000, N2 = 2000?

Species 1 wins

Species 2 wins

Stable Coexistence

Unstable Coexistence

Q:

What do you predict is the competitive outcome, if, given the Scenario 1 information above, you have a starting density where N1 = 700, N2 = 50?

Species 1 wins

Species 2 wins

Stable Coexistence

Unstable Coexistence

Answer 1

Answer: Interspecific competition occurs between individuals of different species that share the use of a resource that limits their growth, survival, or reproduction.

Species within similar resources compete.

K1 and K2 are the carrying capacity for species 1 and species 2, respectively. The values means that this will be the highest number of respective species in the absence of the other species.

12 is the effect of species 1 on species 2. 21 is the effect of species 2 on species 1. These are the competitive coefficients. value greater than 0 indicates that there are some resource overlapping.

According to the Lotka-Volterra model of interspecific competition,

Assuming that the polation size is unchanged over time, zero growth isocline can be computed for both the species.

In the starting density, N1 = 10, N2 = 20, there will stable coexistance. It is because the values fall below the isocline for both the species. The intercept of the carrying capacities for both the species is lower and hence both the species will co-exist. The isoclines cross each other, hence, niether species will win.

In the starting density, N1 = 1000, N2 = 2000, there will coexistance but might be unstable as they fall outside the isoclines.

In the starting density, N1 = 700, N2 = 50, there will be stable coexistance as the point fall below the isoclines.