Island tameness
Encyclopedia
Island tameness is the tendency of many populations and 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...

 of animals living on isolated island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

s to lose their wariness of potential predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

, particularly of large animals. The term is partly synonymous with ecological naïvete, which also has a wider meaning referring to the loss of defensive behaviors and adaptation
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....

s needed to deal with these "new" predators. Species retain such wariness of predators that exist in their environment, for example a Hawaiian Goose
Hawaiian Goose
The Nene, also known as Nēnē and Hawaiian Goose, is a species of goose endemic to the Hawaiian Islands. The official bird of the state of Hawaii, the Nene is exclusively found in the wild on the islands of Maui, Kauai and Hawaii...

 retains its wariness of hawks, but lose such behaviors associated with mammals or other predators not found in their historical range.

Island tameness can be highly maladaptive in situations where humans have introduced
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...

 predators, intentionally or accidentally, such as pigs, dogs, rats or cats, to islands where ecologically
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...

 naïve fauna lives. It has also made many island species
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...

, such as the long-extinct Dodo
Dodo
The dodo was a flightless bird endemic to the Indian Ocean island of Mauritius. Related to pigeons and doves, it stood about a meter tall, weighing about , living on fruit, and nesting on the ground....

 or the Short-tailed Albatross
Short-tailed Albatross
The Short-tailed Albatross or Steller's Albatross, Phoebastria albatrus, is a large rare seabird from the North Pacific. Although related to the other North Pacific albatrosses, it also exhibits behavioural and morphological links to the albatrosses of the Southern Ocean...

, vulnerable to human hunting. In many instances the native species are unable to learn to avoid new predators, or change their behavior to minimize their risk. This tameness is eventually lost or reduced in some species but many island populations are too small or breed too slowly for the affected species to adapt quickly enough. When combined with other threats, such as habitat loss, this has led to the extinction of several species (such as the Laysan Rail
Laysan Rail
The Laysan Rail or Laysan Crake was a tiny inhabitant of the Northwest Hawaiian Island of Laysan. This small island was and still is an important seabird colony, and sustained a number of endemic species, including the rail. It became extinct due to habitat loss by domestic rabbits, and ultimately...

 and the Stephens Island Wren
Stephens Island Wren
The Stephens Island Wren or Lyall's Wren was a nocturnal, flightless, insectivorous passerine.-Habitat:...

) and continues to threaten several others. The only conservation
Conservation biology
Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...

 techniques that can help endangered species threatened by novel introduced species are creating barriers to exclude predators or eradicating
Island restoration
The ecological restoration of islands, or island restoration, is the application of the principles of ecological restoration to islands and island groups. Islands, due to their isolation, are home to many of the world's endemic species, as well as important breeding grounds for seabirds and some...

 those species. New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

has pioneered the use of offshore islands free of introduced species to serve as wildlife refuges for ecologically naïve species.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK