Open main menu
Three main types of population distribution are (from top to bottom) regular/uniform, random/scattered, and clustered/grouped.

In biology, the range of a species is the geographical area within which that species can be found. Within that range, distribution is the general structure of the species population, while dispersion is the variation in its population density.

Range is often described with the following qualities:

  • Sometimes a distinction is made between a species' natural, endemic, indigenous, or native range, where it has historically originated and lived, and the range where a species has more recently established itself. Many terms are used to describe the new range, such as non-native, naturalized, introduced, transplanted, invasive, or colonized range.[1] Introduced typically means that a species has been transported by humans (intentionally or accidentally) across a major geographical barrier.[2]
  • For species found in different regions at different times of year, especially seasons, terms such as summer range and winter range are often employed.
  • For species for which only part of their range is used for breeding activity, the terms breeding range and non-breeding range are used.
  • For mobile animals, the term natural range is often used, as opposed to areas where it occurs as a vagrant.
  • Geographic or temporal qualifiers are often added, such as in British range or pre-1950 range. The typical geographic ranges could be the latitudinal range and elevational range.

The following types of distribution patterns are recognized:

  • Regular/uniform: Individuals are evenly spaced.
  • Random/scattered
  • Clustered/grouped: Individuals are placed in a few areas.
  • Aggregated/clumped/contiguous: Individuals are closer together than they would be if they were randomly or evenly distributed.[3]
  • Disjunct: Two or more areas of contiguous distribution are considerably separated from each other, geographically.

Bird wildlife corridorsEdit

One common example of bird species' ranges are land mass areas bordering water bodies, such as oceans, rivers, or lakes; they are called a coastal strip. A second example, some species of bird depend on water, usually a river, swamp, etc., or water related forest and live in a river corridor. A separate example of a river corridor would be a river corridor that includes the entire drainage, having the edge of the range delimited by mountains, or higher elevations; the river itself would be a smaller percentage of this entire wildlife corridor, but the corridor is created because of the river.

A further example of a bird wildlife corridor would be a mountain range corridor. In the U.S. of North America, the Sierra Nevada range in the west, and the Appalachian Mountains in the east are two examples of this habitat, used in summer, and winter, by separate species, for different reasons.

Bird species in these corridors are connected to a main range for the species (contiguous range) or are in an isolated geographic range and be a disjunct range. Birds leaving the area, if they migrate, would leave connected to the main range or have to fly over land not connected to the wildlife corridor; thus, they would be passage migrants over land that they stop on for an intermittent, hit or miss, visit.

See alsoEdit


  1. ^ Colautti, Robert I.; MacIsaac, Hugh J. (2004). "A neutral terminology to define 'invasive' species" (PDF). Diversity and Distributions. 10 (2): 135–41. doi:10.1111/j.1366-9516.2004.00061.x. ISSN 1366-9516. 
  2. ^ Richardson, David M.; Pysek, Petr; Rejmanek, Marcel; Barbour, Michael G.; Panetta, F. Dane; West, Carol J. (2000). "Naturalization and invasion of alien plants: concepts and definitions". Diversity and Distributions. 6 (2): 93–107. doi:10.1046/j.1472-4642.2000.00083.x. ISSN 1366-9516. 
  3. ^ "Aggregated/clumped/contiguous distribution".