interspecific competition modeling

competition coefficient (alpha)

the magnitude of the negative effects of one individual of species has on the population growth rate of species

competition coefficient is greater than 1

an individual of species 2 has greater competitive effect than an individual of species 2

• inter > intra

competition coefficient is less than 1

an individual of species 2 has less competitive effect than an individual of species 1

• inter < intra

competition coefficient is equal to 1

an individual of species 2 has the same competitive effect as an individual of species 1

• inter = intra

state space graph

plotting N2 on the y axis against N1 on the y-axis

• allows to understand if there will be competitive exclusion or coexistence

herbivores

feed on plants but usually don’t kill the entire plant

predators

kill and feed on other animals

• carnivores or omnivores

two types of herbivores

• grazers

• browsers

grazers

feed on low-growing, non-woody plants

browsers

feed on high growing biomass, woody plants, nutrient poor

exclosure experiments

a tool to study the effects of herbivory or predation on a species or community by using fences, mesh, or inaccessible position

consumption effects

direct effects of predators on prey populations through the capture and consumption of living prey

non-consumptive effects

changes to prey that are due to the presence of predators, includes shifts in behaviours, stress physiology and even morphological traits

capture efficiency (b)

the proportion of encounters between predators and prey that results in the predator capturing/eating the prey

conversion factor (c )

essentially how many prey are required to produce one predator

• how many prey individuals a female needs to consume to make on offspring

joint equilibrium point

the point at which the two isoclines of zero growth meet

• where both populations are balanced in equilibrium with no increases or decreases in the population size of either group.