Assisted migration of species

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An increasing number of global warming experts have called for new drastic conservation tactics, such as assisted migration, to save species, in the face of the growing threat of climate change. They argue that both the rapid rate of climate change and the presence of human-made barriers to natural movement will prevent many species from shifting where they live in response to changes in local climate.


Why should I be aware of this?

  • As the reality of global warming sinks in, species are already becoming endangered and even going extinct because of climate change. Therefore, human-assisted translocation of species may be necessary to ensure colonization of new geographic regions as parts or all of the historical species' range becomes unsuitable.
  • Assisted migration is still a controversial concept among biologists and many consider it a relatively drastic option.

All about assisted migration of species

The Bay checkerspot butterfly was once a common sight in the San Francisco Bay area, but development and invasive plants have wiped out much of its grassland habitat and studies suggest that climate change will push the insect to extinction. Efforts to save the butterfly by saving the remaining patches where it survives have been proving futile because of global warming.

Once the plants the butterflies depend on for food shift their growing seasons, the caterpillars have little to eat. Many other species may face a similar threat, and conservation biologists are beginning to confront the question of how to respond.

One of the most radical strategies

Assisted migration is one of the most radical strategies which involves picking up species up and moving them hundreds of miles to a cooler place.

The idea was first mooted more than a decade ago by an international team of conservation scientists from Australia, the United Kingdom and United States calling for new conservation tactics, such as assisted migration, in the face of the growing threat of climate change.

The conservationists argue that though assisted migration can never be a major solution for wildlife, the method could be used to help a few species that biologists and the public deem to be important enough for the effort and could otherwise go extinct.

The species, however, should be such that they can be collected raised and moved easily. Their habitat requirements would need to be well understood, and there would need to be viable habitat options outside of the species' current range.

Evidence of climate change everywhere

Conservationists have found evidence of climate change nearly everywhere they looked. They discovered that plants and animals have shifted their ranges by about six kilometers per decade toward the poles during the past quarter of a century. Spring events, such as blooming, frog breeding and migrant bird arrivals, have advanced 2.3 days per decade. Tropical pathogens are moving up in latitude and striking species not adapted to deal with them. About two thirds of the 110 known harlequin frog species in Costa Rica are believed to be extinct, their temperature-weakened immune systems devastated by a lethal fungus itself taking advantage of warmer temperatures.

Last December the probable extinction was announced of the first mammal because of climate change: the white lemuroid possum from Queensland, Australia. The possum, which lived only above 1,000 meters in altitude, could be killed by as little as five hours in temperatures greater than 30 degrees Celsius (86 degrees Fahrenheit).


  • Animals and plants will also have to move quickly. If a species cannot keep up with the shifting climate, its range will shrink. Species that are already limited to small ranges may not be able to survive the loss. [1]
  • In 2004, an international team of scientists estimated that 15 percent to 37 percent of species would become extinct by 2050 because of global warming. [1]

90 degrees

Today species are going to find it more difficult to move on their own compared to when the planet warmed at the end of past ice ages. At that time retreating glaciers left behind empty landscapes. Today, the clutter of cities, farms and other human settlements will make the movement that much more difficult. [1]


  • Can "Assisted Migration" Save Species from Global Warming?
  • Global warming experts recommend assisted migration to save species
  • A Radical Step to Preserve a Species: Assisted Migration


  1. 1.0 1.1 1.2 New York Times