Conservation Glossary

The following terms are common in the literature associated with science and conservation in Galapagos. Also included below are the conservation status categories as developed by the International Union on Conservation of Nature and Natural Resources (IUCN). Click on any of the terms below to learn its definition:

Adaptive radiation
Captive Breeding
Captive Rearing
Endemic – Native or Indigenous – Exotic or Introduced – Invasive
Eradication – Control – Biological Control
Reintroduction – Repatriation – Translocation
Sustainable Development
Sustainable Use
Taxon: Species – Subspecies

Threat Categories – as defined by the IUCN

  1. Extinct (EX)
  2. Extinct in the Wild (EW)
  3. Critically Endangered (CR)
  4. Endangered (EN)
  5. Vulnerable (VU)
  6. Near Threatened (NT)
  7. Least Concern (LC)
  8. Data Deficient (DD)
  9. Not Evaluation (NE)


Adaptive Radiation:

The rapid speciation of a single or a few species to fill many ecological niches; an evolutionary process driven by mutation and natural selection. It often occurs when a species arrives in a new ecosystem. In the case of isolated archipelagos, like Galapagos, when a new species becomes established, it can undergo rapid divergent evolution. Darwin’s finches and the Scalesia plants are some of the best examples of adaptive radiation in Galapagos, with many species deriving from single ancestor species.


The full range of natural variety and variability within and among living organisms, and the ecological and environmental complexes in which they occur. It encompasses multiple levels of organization, including genes, species, communities, and ecosystems. In Galapagos approximately 95% of the original biodiversity still exists.

Captive Breeding:

The process of breeding rare or endangered species in human controlled environments with restricted settings, such as wildlife preserves, zoos, or other conservation facilities. Sometimes, as in the case of Galapagos, the process includes the release of individuals into the wild.

Captive Rearing:

Rearing young animals in captivity; can include egg incubation. The eggs/young may be from a captive breeding program or be transferred to the captive environment directly from the wild.

In Galapagos, captive breeding and rearing is used for the Española tortoises (the 15 adults from the original population are maintained at the breeding and rearing center for annual nest and egg production) and is being initiated for both the Mangrove Finch and the Floreana mockingbird. Captive rearing is used for the other tortoise populations included in the Tortoise Center; for those populations, eggs and/or hatchlings are brought to the Center from wild nests.


An ecosystem consists of a dynamic set of living organisms (plants, animals, and microorganisms) all interacting among themselves and with the environment in which they live.

An ecosystem does not have precise boundaries – it can be as small as a pond or a dead tree, or as large as the Earth itself. An ecosystem can also be defined in terms of its vegetation, animal species, or type of relief. The major ecosystems are generally described as:

  • Aquatic ecosystems – saltwater or freshwater ecosystems
  • Terrestrial ecosystems – forests, prairies, deserts, etc.

Endemic, – Native or Indigenous – Exotic or Introduced – Invasive

  • Endemic: A biological taxon (genus, species, subspecies, variety, etc.) native to and restricted to a particular area or region and not found naturally anywhere else in the world. Many species in Galapagos are endemic to specific islands or volcanoes, while others are endemic to the archipelago as a whole. Endemism on islands is generally much higher than on continents. Endemic species are a subset of native or indigenous species.
  • Native or Indigenous: A biological taxon (genus, species, subspecies, variety, etc.) native to a particular area or region; can be found naturally in other areas.
  • Exotic or Introduced: A biological taxon (genus, species, subspecies, etc.) that is not native or indigenous to a particular area or region and that has been accidentally or deliberately introduced into the area. Subsequent establishment and range expansion of introduced species may or may not involve human activity. Some introduced species never become established. However, once established some introduced species become invasive.
  • Invasive: A species that is non-native or introduced to an ecosystem that becomes established, spreads, and is likely to cause damage to biodiversity, agricultural production, or human health. Invasive species can be plants, animals, and other organisms (e.g., microbes). They can compete with and displace native plants and animals, alter ecosystem functions and cycles significantly, hybridize with native species, and promote other invaders.

Eradication – Control – Biological Control

  • Eradication: Application of measures to totally eliminate a pest or weed species from a defined area. In the case of Galapagos, eradications are commonly defined at the level of individual islands. There are three conditions that must be met before eradication is deemed a viable option. These are: 1) the probability of recolonization must be near zero; 2) all individuals in the population must be at risk (e.g., animals that become trap-shy, avoid baits, or cannot be detected by current techniques would not be at risk); and 3) individuals must be removed at rates faster than their natural rate of increase at all densities. The best examples of successful eradications in Galapagos are the removal of goats, donkeys, and pigs from several of the larger islands.
  • Control: The suppression or containment of a population of an invasive or pest species; a continuous activity. If eradication is not feasible for either technological or financial reasons, a strategic approach for control is required to minimize impacts and/or reduce the spread of the invasive species. The ultimate purpose of control is to preserve native species, communities, and/or functioning ecosystems, as well as preserving health of both humans and the native ecosystem. Control methods include: 1) chemical control (pesticides, herbicides, fungicides); 2) mechanical control (physically removing the invasive species or changing habitat conditions); and 3) biological control (introducing a natural enemy – parasite or predator).
  • Biological Control: Biological control is the use by humans of a specially chosen living organism to control a particular pest species. This chosen organism might be a predator, parasite, or disease, which will attack the harmful plant or animal. It is a form of manipulating nature to achieve a desired effect. The best example in Galapagos is the successful use of the Australian lady bug to control the introduced, aggressive cottony cushion scale.


Evolution is a process that results in heritable changes in a population over many generations. Evolution occurs within populations not individuals. Charles Darwin’s Theory of Natural Selection suggests the probable mechanism by which evolution occurs.


A group of organisms of one species that interbreed and live in the same place at the same time. Both research and management in Galapagos tend to focus on populations rather than species. This allows scientists and natural resource managers to work at the most conservative level, ensuring not only the survival of species but of distinct populations of species.


All activities directed at preventing the introduction and/or spread of quarantine pests or to ensure their control. Inspection and quarantine in Galapagos is a package of activities or legal measures imposed on the entry of animals, plants, agricultural products, and other organisms and micro-organisms, including the time they must remain isolated in order to prevent, control, or delay the introduction of pests potentially harmful to the archipelago.

Reintroduction – Repatriation – Translocation

  • Reintroduction: The intentional release of individuals of a species into an area formally occupied by that species. This could be considered a subset of Repatriation. In Galapagos, the release of Floreana mockingbirds back on Floreana will be the first reintroduction.
  • Repatriation: The intentional release of individuals of a species into an area formally or currently occupied by that species. In Galapagos, this has been used for giant tortoises and land iguanas. Only in the case of giant tortoises from Española was the release into an area formally occupied, only because the last of the original tortoises were removed from Española for captive breeding purposes.
  • Translocation: The intentional release of individuals of a species into geographic areas not historically occupied by the species. This usually involved moving an animal or population of animals away from an area where they are immediately threatened to an area where they would be less prone to extinction. In the case of Galapagos, translocations have been used for the protection of a population (examples include the translocation of land iguanas from Santa Cruz to the islets of Venecia and the planned translocation of endemic rice rats on Santiago to Bainbridge Rocks). Another case of translocation in Galapagos is the transfer of the sterilized adult tortoises to the island of Pinta; in this case, the primary goal of the project is the restoration of the island of Pinta and its ecological and evolutionary processes.
  • Definition of success: The definition of success for conservation programs involving reintroductions, repatriations, and translocations is the establishment (or enhancement) of a viable, self-sustaining population.

Sustainable Development:

Sustainable development is a pattern of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only in the present but in the indefinite future.

Sustainable Use:

The use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity.

Taxon: Species – Subspecies

  • Taxon (pl. Taxa): any taxonomic or classification unit; e.g., genus, species, etc.
  • Species: The fundamental biological classification of organisms. Members of a species can generally only breed among themselves and show persistent differences from members of allied species.
  • Subspecies: A taxonomic subdivision of a species, consisting of an inter-breeding, usually geographically isolated population of organisms.

Threat Categories (as defined by the IUCN):

  • Extinct (EX):

    A taxon is Extinct when there is no reasonable doubt that the last individual has died. A taxon is presumed Extinct when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon’s life cycle and life form.

  • Extinct in the Wild (EW):

    A taxon is Extinct in the Wild when it is known only to survive in cultivation, in captivity or as a naturalized population (or populations) well outside the past range. A taxon is presumed Extinct in the Wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon’s life cycle and life form.

  • Critically Endangered (CR):

    A taxon is Critically Endangered when the best available evidence indicates that it meets any of the criteria A to E for Critically Endangered (see Section V), and it is therefore considered to be facing an extremely high risk of extinction in the wild.

  • Endangered (EN):

    A taxon is Endangered when the best available evidence indicates that it meets any of the criteria A to E for Endangered (see Section V), and it is therefore considered to be facing a very high risk of extinction in the wild.

  • Vulnerable (VU):

    A taxon is Vulnerable when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable (see Section V), and it is therefore considered to be facing a high risk of extinction in the wild.

  • Near Threatened (NT):

    A taxon is Near Threatened when it has been evaluated against the criteria but does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.

  • Least Concern (LC):

    A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened. Widespread and abundant taxa are included in this category.

  • Data Deficient (DD):

    A taxon is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. A taxon in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution are lacking. Data Deficient is therefore not a category of threat. Listing of taxa in this category indicates that more information is required and acknowledges the possibility that future research will show that threatened classification is appropriate. It is important to make positive use of whatever data are available. In many cases great care should be exercised in choosing between DD and a threatened status. If the range of a taxon is suspected to be relatively circumscribed, and a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified.

  • Not Evaluated (NE):

    A taxon is Not Evaluated when it is has not yet been evaluated against the criteria.