Lab: Spatial Paterns

Question 1

Spatial Patterns

Answer 1

Discribes the distribution of individuals within their habitat.

“Movements, family groupings, and differential survival create spatial patters that vary from one population to another. A population can also change the way it is scattered through space as seaons or conditions change.”

Question 2

Dispersion

Answer 2

Refers to the evenness of the population’s distributuion through space. (note: this is not to be confused with dispersal, which describes movement rather than pattern.)
There are 3 types of dispersion: uniform, random, and aggregated.

Question 3

Uniform Distribution

Answer 3

High dispersion, spaced out evenly from each individual to the next; found in populations in which the distance between neighboring individuals is maximized.

s2/ x̄ < 1.0

Question 4

Random Distribution

Answer 4

Inremediate dispersion, individuals are scattered, as the name dictates, randomly.

s2/ x̄ ≈ 1.0

Question 5

Aggregated Distribution

Answer 5

Low dispersion, individials are clumped together in groups; also called Clusted distribution

s²/ x̄ > 1.0

Question 6

Quadrat

Answer 6

Refers to quadrat sampling, which is the typical approach to measure dispersion in a populations.

Quadrats are small plots, of uniform shape and size, placed in randomly selected sites for sampling purposes

Question 7

Index of Dispersion

Answer 7

Or, the variance/mean ratio (symbolized as: s²/ x̄ ) yields a value that is:

around 1

• indicates random dispersion

more than 1

• indicates aggregation

less than 1

• indicates uniformity
  (note: a high value of s²/ x̄ means high aggregation [very clumped], but low dispersion [not very spread out])