Species translocation
Encyclopedia
Species translocation is an effective management strategy and important topic in conservation biology
. Translocation is the movement of a species, by people, from one area to another. This management tool decreases the risk of extinction
by increasing the range of a species, augmenting the numbers in a critical population, or establishing new populations thus reducing the risk of extinction. This improves the level of biodiversity
in the ecosystem
.
), improvement of hunting and fishing (fallow deer
), ornamentation of roads (rhododendron
) or maintenance (sweet chestnut
). In the past, translocation introductions of non-native species to ecosystems far outweighed the benefits of them. For example, eucalyptus
trees were introduced in California during the Gold Rush as a fast growing timber source. By the early 1900s, however, this did not happen because of early harvesting and the splitting and twisting of cut wood. Now the introduction of non-native
eucalyptus, particularly in the Oakland Hills is causing competition among native plants and encroaching on habitat
for natural wildlife.
The second of the three types of translocation is re-introduction. Re-introduction is the deliberate or accidental translocation of a species into the wild in areas where it was indigenous
at some point, but no longer at the present. Re-introduction is used as a wildlife management
tool for the restoration
of an original habitat when it has become altered or species have become extinct due to over-collecting, over-harvesting, human persecution, or habitat deterioration.
Lastly, the third type of translocation is re-stocking. Re-stocking is the translocation of an organism into the wild into an area where it is already present. Re-stocking is considered as a conservation strategy where populations have dropped below critical levels and species recovery is questionable due to slow reproductive rates or inbreeding. The World Conservation Union
recommends that re-stocking only occur when the causes of population decline have been removed, the area has the capacity to sustain the desired population, and individuals are of the same race as the population into which they are released but not from genetically impoverished or cloned stock.
Between 1973 and 1989 an estimated 515 translocations occurred per year in the United States, Canada, New Zealand and Australia. The majority were conducted in the United States. Birds were the most frequently translocated, followed by threatened and endangered species, then non-game species. Of the 261 translocations in the United States reported wild species were most frequently translocated, and the greatest number occurred in the Southeast.
, of Australia, is a nature conservation program which plays an important role in protecting Australia’s native animal population. More importantly, Western Shield also has programs specializing in translocation of endangered and threatened animals. Founded in 1996, it's the most successful wildlife conservation program in Australia and in 2006, it still remains among the largest in the world. The program has already had significant success: three native mammals in Australia – the woylie
, quenda and tammar wallaby
– have been removed from the threatened species list, many populations of native animals have recovered or been re-established in their former ranges, and the restoration of ecological processes has begun. From 1996 to 2000, Western Shield has taken part of 60 translocations, mostly introductions, of 17 species all over the country on private and interstate lands.
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...
. Translocation is the movement of a species, by people, from one area to another. This management tool decreases the risk of 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...
by increasing the range of a species, augmenting the numbers in a critical population, or establishing new populations thus reducing the risk of extinction. This improves the level of biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
in the ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
.
Three types of translocations
The first of three types of translocation is introduction. Introduction is the deliberate or accidental translocation of a species into the wild in areas where it does not occur naturally. Introduction of non-native species occurs for a variety of reasons. Examples are economic gain (Sitka SpruceSitka Spruce
Picea sitchensis, the Sitka Spruce, is a large coniferous evergreen tree growing to 50–70 m tall, exceptionally to 95 m tall, and with a trunk diameter of up to 5 m, exceptionally to 6–7 m diameter...
), improvement of hunting and fishing (fallow deer
Fallow Deer
The Fallow Deer is a ruminant mammal belonging to the family Cervidae. This common species is native to western Eurasia, but has been introduced widely elsewhere. It often includes the rarer Persian Fallow Deer as a subspecies , while others treat it as an entirely different species The Fallow...
), ornamentation of roads (rhododendron
Rhododendron
Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...
) or maintenance (sweet chestnut
Sweet Chestnut
Castanea sativa is a species of the flowering plant family Fagaceae, the tree and its edible seeds are referred to by several common names such Sweet Chestnut or Marron. Originally native to southeastern Europe and Asia Minor, it is now widely dispersed throughout Europe and parts of Asia, such as...
). In the past, translocation introductions of non-native species to ecosystems far outweighed the benefits of them. For example, eucalyptus
Eucalyptus
Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...
trees were introduced in California during the Gold Rush as a fast growing timber source. By the early 1900s, however, this did not happen because of early harvesting and the splitting and twisting of cut wood. Now the introduction of non-native
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...
eucalyptus, particularly in the Oakland Hills is causing competition among native plants and encroaching on 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...
for natural wildlife.
The second of the three types of translocation is re-introduction. Re-introduction is the deliberate or accidental translocation of a species into the wild in areas where it was indigenous
Indigenous (ecology)
In biogeography, a species is defined as native to a given region or ecosystem if its presence in that region is the result of only natural processes, with no human intervention. Every natural organism has its own natural range of distribution in which it is regarded as native...
at some point, but no longer at the present. Re-introduction is used as a wildlife management
Wildlife management
Wildlife management attempts to balance the needs of wildlife with the needs of people using the best available science. Wildlife management can include game keeping, wildlife conservation and pest control...
tool for the restoration
Restoration ecology
-Definition:Restoration ecology is the scientific study and practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human intervention and action, within a short time frame...
of an original habitat when it has become altered or species have become extinct due to over-collecting, over-harvesting, human persecution, or habitat deterioration.
Lastly, the third type of translocation is re-stocking. Re-stocking is the translocation of an organism into the wild into an area where it is already present. Re-stocking is considered as a conservation strategy where populations have dropped below critical levels and species recovery is questionable due to slow reproductive rates or inbreeding. The World Conservation Union
World Conservation Union
The International Union for Conservation of Nature and Natural Resources is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The organization publishes the IUCN Red List, compiling information from a network of...
recommends that re-stocking only occur when the causes of population decline have been removed, the area has the capacity to sustain the desired population, and individuals are of the same race as the population into which they are released but not from genetically impoverished or cloned stock.
Trends of translocations
Programs in action today: Western Shield
Western ShieldWestern Shield
Western Shield, managed by Western Australia's Department of Environment and Conservation, is a nature conservation program, safeguarding Western Australia's native animals and rescuing them from extinction...
, of Australia, is a nature conservation program which plays an important role in protecting Australia’s native animal population. More importantly, Western Shield also has programs specializing in translocation of endangered and threatened animals. Founded in 1996, it's the most successful wildlife conservation program in Australia and in 2006, it still remains among the largest in the world. The program has already had significant success: three native mammals in Australia – the woylie
Woylie
The Woylie , also known as the Brush-tailed Bettong, is a small marsupial that belongs to the genus Bettongia. It is endemic to Australia...
, quenda and tammar wallaby
Tammar Wallaby
The Tammar Wallaby , also known as the Dama Wallaby or Darma Wallaby, is a small member of the kangaroo family and is the model species for research on kangaroos and marsupials. It is found on offshore islands on the South Australian and Western Australian coast...
– have been removed from the threatened species list, many populations of native animals have recovered or been re-established in their former ranges, and the restoration of ecological processes has begun. From 1996 to 2000, Western Shield has taken part of 60 translocations, mostly introductions, of 17 species all over the country on private and interstate lands.
Reasons for failures
Often, when conducting translocation programs, differences in specific habitat types between the source and release sites are not evaluated as long as the release site contains suitable habitat for the species. Translocations could be especially damaging to endangered species citing the failed attempt of Bufo hemiophys baxteri in Wyoming and B. boreas in the Southern Rocky Mountains. For species that have declined over large areas and long periods of time translocations are of little use. Maintaining a large and widely dispersed population of amphibians and other species is the most important aspect of maintaining regional diversity and translocation should only be attempted when a suitable unoccupied habitat exists.Further reading
- Griffith, Brad, Michael Scott, James Carpenter, Christine Reed. “Translocation as a species conservation tool: status and strategy.” 1989. ScienceScience (journal)Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
. 245 (4917): 477-480.