BIOS 6150: Ecology
Dr. S. Malcolm
Biological Sciences
Week 5: Interspecific Competition
MULTI-SPECIES INTERACTIONS
Lotka-Volterra Competition
Using the Lotka-Volterra Competition model set to run to a steady state and
the gridding function answer the following questions:
At
N1 = 20
r1 = 0.5
K1 = 500 α = 0.5
N2 = 20
r2 = 0.5
K2 = 500 β = 0.5
1) What is the competitive outcome?
2) At what population sizes do the N1 and N2 populations end up at
when they reach steady state?
N1 =
N2 =
3) Is there a negative impact on the two populations?
__________
4) Is K1 larger or smaller than K2α (give numbers)?
__________
5) Is K2 larger or smaller than K1β (give numbers)?
At
N1 = 20
Bios 6150: Ecology
r1 = 0.7
K1 = 700 α = 0.7
Interspecific Competition Exercise
Page - 1
N2 = 20
r2 = 0.5
K2 = 500 β = 0.5
6) At what population sizes do the N1 and N2 populations end up at
when they reach steady state?
N1=
N2 =
7) Is K2 > or < than K1β (give numbers)?
8) Is K1 > or < than K2α (give numbers)?
9) What are the criteria for coexistence in terms of K1, K2, α and β?
Give your own values for N, r, K, α and β to satisfy the criteria in the
following questions.
10) ) if K1β > K2 and K1 > K2α which species wins?
11) if K2α > K1 and K2 > K1β which species wins?
12) Does changing N or r have any impact on the outcome
of either 10) or 11)?
13) if K2α > K1 and K1β > K2 which species wins?
14) Does changing N or r have any impact on the outcome
of 13)?
Bios 6150: Ecology
Interspecific Competition Exercise
Page - 2