Determining Conservation Status
The International Union for the Conservation of Nature (IUCN)
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IUCN has published documents called the Red Data Books for the past 4 decades.
The Red Data Books assess the conservation status of a particular species in order to
highlight species threatened with extinction and to promote their conservation
The Red List is an inventory of all threatened species
The genetic diversity of plants and animals in the Red List is an irreplaceable resource
which IUCN uses to conserve through increased awareness
These species also represent key building blocks of ecosystems
Information on their conservation status provides the basis for making informed
decisions about conserving biodiversity from local to global levels.
Highlights plants and animals facing a higher risk of global extinction than others
Factors Used To Determine Conservation Status of a Species
Various factors are used to determine the conservation status of a species and a sliding scale
operates (from severe threat to low risk). The Red List is complicated classification system.
Factors:
 population size
 reduction in population size
 numbers of mature individuals
 geographic range and degree of fragmentation
 quality of habitat
 area of occupancy
 probability of extinction
IUCN Categories
Species are classified in nine groups, set through criteria such as rate of decline, population
size, area of geographic distribution, and degree of population and distribution fragmentation.
Extinct (EX) - No individuals remaining.
Extinct in the Wild (EW) - Known only to survive in captivity, or as a naturalized population outside
its historic range.
Critically Endangered (CR) - Extremely high risk of extinction in the wild.
Endangered (EN) - High risk of extinction in the wild.
Vulnerable (VU) - High risk of endangerment in the wild.
Near Threatened (NT) - Likely to become endangered in the near future.
Least Concern (LC) - Lowest risk. Does not qualify for a more at risk category. Widespread and
abundant taxa are included in this category.
When discussing the IUCN Red List, the official term "threatened" is a grouping of three categories:
Critically Endangered, Endangered, and Vulnerable.
Examples of Species on the Red List with Reasons
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Peacock parachute tarantula (India) – single location, restricted range, habitat loss
due to logging for firewood and timber
European eel – historically low numbers, declining numbers, over-fishing, introduction
of a parasite (limiting the ability of the eels to reach their spawning grounds), and dam
construction blocking migration routes.
“Queen of the Andes” (a high Andean plant found from Peru to Bolivia) –
isolated, small population size, seeds only once in 80 years before dying, climate
change may be limiting its ability to flower.
The Indri (a primate from Madagascar) – loss of rainforest habitat for timber, fuel &
slash and burn agriculture, greatly reduced population numbers (50% reduction over
past 35 years)
Fishing cat (South East Asian wetlands) – skilful swimmer, loss of habitat due to
human settlement, draining of wetlands for agriculture, pollution, excessive hunting,
and wood cutting, also over-fishing has significantly reduced its prey
When Conservation is Too Little-Too Late
Sometimes conservation actions come too late to save a species from existence.
Here are some extinct species and the reasons for their extinction:
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Small habitat area – Holridge’s toad, St. Helena olive, Percy Island flying fox
Narrow geographic area – golden toad
Poor competitor – Holridge’s toad (deaf & mute), dodo (flightless bird)
Human intervention – dodo (introduction of rats), thylacine (introduction of non-native
species to Tasmania), desert rat kangaroo
Disease (introduction of a non-native disease so no local immunity) – Darwin’s
Galapagos mouse
Hunting (over-hunting of species to extinction) – Bali tiger, passenger pigeon,
thylacine, western black rhino, Queen of Sheba’s gazelle, Madagascan pygmy hippo,
Steller’s sea cow
Shallow gene pool (little or no genetic variation so little chance to adapt to changing
environment) – North elephant seal, saiga antelope
Co-extinction (loss of one species causes extinction of another) – the bird lice found
on passenger pigeons went extinct when their hosts did
Questions about Conservation
There are no correct answers to the following questions!!! However, they do raise some
interesting issues for debate.
1. Do some organisms have more of a right to conservation than others? How can this be
justified?
2. Do pandas have a greater to conservation than lichens?
3. Do “pests” or pathogenic organisms have a right to be conserved?
4. To what extent are these arguments based on emotion and to what extent on reason? How
does this affect their validity?
Case Studies
Extinct Species: Falkland Islands Wolf (dusicyon australis)
Description
It was the only native land mammal in Falkland Islands. Charles Darwin visited the islands in
1833 and described the animal as “common and tame”. Dusicyon means “foolish dog” and is
thought to refer to its lack of fear of man. The wolf became extinct in 1876, the first known
canid to have gone extinct in historical times.
Ecological Role
This wolf lived in burrows and most likely survived on a diet of seabirds, seal pups, and
probably even on vegetation. It was the only predatory mammal on the Falklands Islands.
Pressures
The settlers on the islands – Scottish sheep farmers with a few French and English – saw the
wolf as a threat to their sheep. There was a large scale operation of poisoning and shooting
the wolf with the aim of pushing ii into extinction. The operation was successful very rapidly
due to the lack of forests (for hiding) and the tameness of the animal (made it easy to lure
with a piece of meat).
There were also U.S. fur traders who hunted the species.
Some conservation efforts were made: A Falkland Islands Wolf lived in the London Zoo in the
United Kingdom in 1868. In December 1870 the zoo got another "Antarctic Wolf", the
surviving half of a pair sent by Mr Byng, the acting colonial secretary of the Falklands. This
animal live only a few years. No conservation measures were taken.
Consequences of Disappearance
The Falkland Islands Wolf was a top predator and as such had an impact on other organism
numbers in the food chain/web.
Critically Endangered Species: Iberian Lynx (lynx pardinus)
Description
The Iberian lynx, also known as the Spanish Lynx, is a critically
endangered species native to the Iberian Peninsula in Southern
Europe. It is the most endangered cat species in the world. The
Iberian lynx resembles other species of lynx, with a short tail,
tufted ears and a ruff of fur beneath the chin. The Iberian lynx
has distinctive, leopard-like spots with a coat that is often light
grey or various shades of light brownish-yellow. It is smaller
than its northern relatives and hunts smaller prey such as
hares. It lives in open scrub rather than forests like its relatives.
The Iberian lynx is the most endangered of 36 big cats.
Ecological Role
The Iberian Lynx is a specialized feeder with rabbits accounting for 80-100% of its food. Lynx
can kill other carnivore species such as foxes and feral cats but do not eat them.
Pressures
The lynx’s specialized diet make it a vulnerable species and rabbit populations have rapidly
declined since the 1950s making a big impact on lynx numbers. The Iberian lynx only
occupies isolated areas of Spain and Portugal. Habitat destruction, deterioration and
alteration have impacted negatively on the lynx for centuries.
The Iberian lynx was protected against hunting in the early 1970s and hunting has declined
since then.
The Iberian lynx and its habitat are fully protected and are no longer legally hunted. Its critical
status is mainly due to habitat loss, poisoning, road casualties, feral dogs and poaching. Its
habitat loss is due mainly to infrastructure improvement, urban and resort development and
tree monocultivation, which serves to break the lynx's distribution area.
Graphic showing Iberian Lynx population in Spain, 19502007
In 1960, there were 4000 Iberian lynx which had declined
to 400 in 2000 and only 100 in 2005.
Methods of Restoring Population
The Iberian lynx is fully protected under Spanish and Portuguese law. Public education and
awareness programs have helped to change attitudes towards the animal. Two international
seminars have been held in 2002 and 2004 to build strategies for saving the lynx. A captive
breeding program has also been established which will lead to re-introduction into the wild
and increasing population numbers. One of the lynx endemic areas has been turned into
Doñana National Park
Improved By Intervention: American Bald Eagle (Haliaeetus leucocephalus)
Description
Also known as the American eagle, the bald eagle was
officially declared as the National Emblem of the United
States in 1782. It is a species unique to North America. The
bald eagle is one of the largest birds in North America with a
wing span of 6-8 feet. Females tend to be larger than males.
They live for up to 40 years in the wild. They have one life
partner.
In the late 20th century the Bald Eagle was on the brink of
extinction in the continental United States, while flourishing
in much of Alaska and Canada. Populations recovered and
stabilized, so the species was removed from the U.S. federal
government's list of endangered species and transferred to
the list of threatened species on July 12, 1995, and it was
removed from the List of Endangered and Threatened
Wildlife in the Lower 48 States on June 28, 2007.
Ecological Role
Bald eagles are found near large bodies of open water (lakes, marshes, seacoasts and
rivers) with an abundant food supply and old-growth trees for nesting and roosting. They live
in every US state except Hawaii. They use a specific territory for nesting, winter feeding or a
year-round residence. Eagles from colder climates migrate south in search of food and some
southern eagles migrate north when the weather is too warm. Their diet consists mainly o fish
but they also eat small animals (ducks, coots, muskrats, turtles, rabbits and snakes).
Pressures
Bald eagle numbers have been estimated to be between 300,000 – 500,000 in the early
1700s. By the 1950s, the population had fallen to 10 000 and to less than 500 pairs by the
early 1960s. The population decline was due to mass shooting of eagles, the use of
pesticides on crops, habitat destruction, contamination of waterways and food sources by a
wide range of poisons and pollutants. For many years, the use of DDT pesticide on crops
caused thinning of the eagle egg shells which broke during incubation reducing reproductive
numbers.
Methods of Restoring Population
DDT use was banned in the US in 1972 and in Canada in 1973. This contributed greatly to
the restoration of eagle numbers.
The bald eagle was listed as endangered in most of the USA from 1967-95 when it was
upgraded to threatened in the lower 48 states. The number of breeding pairs increased from
500 to over 10 000 in 2007 when they were removed from threatened status.
Since it was de-listed the primary law protecting bald eagles has shifted from the Endangered
Species Act to the Bald and Golden Eagle Act. It has been assigned a risk level of Least
Concern category on the IUCN Red List.
Although numbers have increased eagles still face hazards that must be closely monitored
and controlled. Even though it is illegal, bald eagles are still harassed, injured and killed by
guns, traps, power lines, windmills, poisons, contaminants and habitat destruction.