Colonisation is the process in biology

Biology

Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

 by which a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 spreads into new areas, regions, and continent

Continent

A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...

s. It is sometimes also referred to as immigration

Immigration

Immigration is the act of foreigners passing or coming into a country for the purpose of permanent residence...

, but colonisation often refers to successful immigration with integration to a community

Community (ecology)

In ecology, a community is an assemblage of two or more populations of different species occupying the same geographical area. The term community has a variety of uses...

, having resisted initial local extinction

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

.

One classic model

Scientific modelling

Scientific modelling is the process of generating abstract, conceptual, graphical and/or mathematical models. Science offers a growing collection of methods, techniques and theory about all kinds of specialized scientific modelling...

 in biogeography

Biogeography

Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 posits that species must continue to colonize new areas through its life cycle

Biological life cycle

A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...

 (called a taxon cycle) in order to achieve longevity

Longevity

The word "longevity" is sometimes used as a synonym for "life expectancy" in demography or known as "long life", especially when it concerns someone or something lasting longer than expected ....

. Accordingly, colonisation and extinction are key components of island biogeography

Island biogeography

Island biogeography is a field within biogeography that attempts to establish and explain the factors that affect the species richness of natural communities. The theory was developed to explain species richness of actual islands...

, a theory that has many applications in ecology

Ecology

Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

, such as analysis of metapopulation

Metapopulation

A metapopulation consists of a group of spatially separated populations of the same species which interact at some level. The term metapopulation was coined by Richard Levins in 1970 to describe a model of population dynamics of insect pests in agricultural fields, but the idea has been most...

s.
.

Scales

The term can be used to describe colonisation on:

• biofilm
  Biofilm
  A biofilm is an aggregate of microorganisms in which cells adhere to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance...
  
   scales: the formation of communities of microorganism
  Microorganism
  A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
  
  s on surfaces.
• small scales: colonising new sites, perhaps as a result of environmental change
  Environmental change
  Environmental change is defined as a change or disturbance of the environment by natural ecological processes, and is described in the following articles:*Climate change*Environment...
  
  .
• large scales: where a species expands its range
  Range (biology)
  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:...
  
   to encompass new areas. This can be via a series of small encroachments or by long-distance dispersal
  Biological dispersal
  Biological dispersal refers to species movement away from an existing population or away from the parent organism. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population...
  
  . The term range expansion is often used.

Means

The term is generally only used to refer to the spread into new areas by natural means, as opposed to introduction or translocation by human agency, potentially becoming invasive species

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 or introduced species

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

.

Species colonization events

Some large-scale notable colonization events in the 20th Century are:

Birds

• the colonisation of the New World
  New World
  The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
  
   by the Cattle Egret
  Cattle Egret
  The Cattle Egret is a cosmopolitan species of heron found in the tropics, subtropics and warm temperate zones. It is the only member of the monotypic genus Bubulcus, although some authorities regard its two subspecies as full species, the Western Cattle Egret and the Eastern Cattle Egret...
  
  
• the colonisation of Britain
  United Kingdom
  The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
  
   by the Little Egret
  Little Egret
  The Little Egret is a small white heron. It is the Old World counterpart to the very similar New World Snowy Egret.-Subspecies:Depending on authority, two or three subspecies of Little Egret are currently accepted....
  
  
• the colonisation of the East Coast
  Atlantic Seaboard
  The Atlantic seaboard watershed is a watershed of North America along both*the Atlantic Canada coast south of the Gulf of Saint Lawrence Watershed &*the East Coast of the United States north of the watershed of the Okeechobee Waterway....
  
   of North America
  North America
  North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
  
   by the Brewer's Blackbird
  Brewer's Blackbird
  The Brewer's Blackbird is a medium-sized New World blackbird, named after the ornithologist Thomas Mayo Brewer....
  
  
• the colonisation-westwards spread across Europe
  Europe
  Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
  
   of the Collared Dove

Dragonflies

• Dragonfly
  Dragonfly
  A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...
  
   - the colonisation of Britain by the Small Red-eyed Damselfly
  Small Red-eyed Damselfly
  The Small Red-eyed Damselfly Erythromma viridulum is a member of the damselfly family Coenagrionidae. It is very similar to the Red-eyed Damselfly.-Appearance:...
  
  

See also

• Colony (biology)
  Colony (biology)
  In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
  
  
• Invasive species
  Invasive species
  "Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
  
   - habitat
  Habitat
  * Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
  
  colonisation, from human introduction