Range (biology)

Population distribution redirects here. For the probability distribution of a statistical population see Probability distribution and Statistical population.

The three basic types of population distribution within an area. From top to bottom: spaced (uniform/regular), random and clumped (aggregated).

In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.

The term is often qualified:

• sometimes a distinction is made between a species' native range and the places to which it has been introduced by human agency (deliberately or accidentally), as well as where it has been re-introduced following extirpation.
• for species which are found in different regions at different times of year, terms such as summer range and winter range are often employed.
• for species where only part of their range is used for breeding activity, the terms breeding range and non-breeding range are not used.
• when discussing mobile animals, the species' natural range is often discussed, as opposed to areas where it occurs as a vagrant.
• geographic or temporal qualifiers are often added e.g. British range or pre-1950 range.

There are at least five types of distribution patterns:

• scattered/random (Random placement)
• clustered/grouped (The majority are placed in one area)
• linear (Their placements form a line)
• radial (Placements form a ' x ' shape)
• Regular/ordered (They are not random at all, but follow a set placement. Much like a grid)

See also

• Biological dispersal
• Colonisation
• Occupancy-abundance relationship
• Species distribution