11/3 Population Ecology I

Number/Abundance

Can be of smaller group (local abundance) or whole population (usually called population size)

Density

number per area of space

How can we use subsampling and density within smaller plots to estimate population size in a much larger area?

Dispersion

Clumped, Uniform, or Random

Clumped (most common)

close to one another; caused by packs or family units or where food is

Uniform

standard amount of space, spread out evenly; due to avoiding one another due to defending territory

Random

could be a result of genetic drift from environmental conditions

Why do we use sampling to estimate population size?

It is impossible to measure the whole (every organism cannot be counted) so samples need to be obtained. A sample is a portion that’s representative of the whole population.

How do we use mark-recapture to estimate population sizes?

A set of animals are captured, counted, tagged and released. After a period of time another capture occurs. Previously tagged animals are counted and unmarked organisms are marked.