Matrix Models Flashcards
How are natural populations structured?
By the distribution of individual attributes (age, sex, size, developmental stage etc) across individuals
Why is population structure important?
Cannot reliably understand and predict population processes without accounting for population structure
What do circles represent in life cycle diagrams?
States
- e.g. age - however could be anything you can measure e.g. size structured population in plants
What do arrows represent in life cycle diagrams?
Possible transitions between states:
- Transitions are numbers that describe rates e.g. survival rates, per capita reproduction rates
- Thickness denotes magnitude
A circular arrow represents individuals that stay in that class, assuming nothing about their survival or reproduction changes
How can population dynamics in time be projected?
Matrix models - repeating these with each new set of individuals
What are the two phases in population size trajectory?
1) Initial transient growth/decline phase
2) Long term constant growth/decline phase
What does a straight line on a log scale tell us?
The population is growing/declining exponentially in the long term - changes by a constant factor each year
- This number is the population growth rate (λ)
How do initial conditions affect short term behaviour?
Start with 100 age 1 individuals:
- Sudden collapse then long term decline
Start with 100 age>2 individuals:
- Sudden boom then long term decline
Do initial conditions affect long term behaviour?
No - slopes are eventually parallel on the log scale for different initial conditions
How are matrix model predictions useful?
Can calculate long term growth to understand whether pop likely to persist or go extinct
Can look at short-term behaviour e.g. to predict impact of reintroduction strategies
R0 and T can be calculated from MPMs
