IUCN RED LIST U3

Question 1

IUCN Red List

Answer 1

Established in 1964
The world’s most comprehensive information source on the global extinction risk status of animal, fungus and plant species.
It is a critical indicator of the health of the world’s biodiversity.

Question 2

Factors used to determine the conservation status of a species (and whether it is prone to extinction):

Answer 2

1. Population Size
2. Trophic Level
3. Degree of fragmentation
4. Degree of specialization
5. Valuable Resources
6. Geographic Range and Distribution
7. Quality of Habitat
8. Reproductive Potential

Question 3

Population size

Answer 3

Small populations have less chance of survival if conditions change. They also tend to have low genetic diversity, so inability to adapt to changing conditions can prove fatal. Many of the large cat species are in this category (cheetah, snow leopard and tiger)

Question 4

Trophic level

Answer 4

Top predators are sensitive to any disturbance in the food chain and any reduction in numbers of species at lower trophic levels can have disastrous consequences. Also, because of the “10% rule” of energy loss through ecosystems, large animals tend to be rare and therefore particularly sensitive to hunters and reductions in population size.

Question 5

Degree of specialization

Answer 5

Many species have a specific diet or habitat requirements: if their specific resource or habitat is under threat, so are they. For example, some orchids rely on a single insect
species to pollinate them, and giant pandas depend almost exclusively on bamboo for food. If the insect or the plant becomes scarce, they dependend on the organism at risk.

Question 6

Geographic range and distribution

Answer 6

When a species has limited range, it is more at risk than widely distributed species. The spoon-billed sandpiper is limited to a small area in the far east Russia, and
there are thought to be fewer than 200 birds leh in the wild. → Low population density

Question 7

Reproductive potential

Answer 7

Animals that have long gestation times have low rates of reproduction, and can take many years to recover from any reduction in population number. This makes them vulnerable to extinction. For example, orangutans have the slowest reproductive rates of all mammal species: they give birth to a single offspring only once every 6 to 8 years; with such a low reproductive rate, even a small decrease in numbers can lead to extinction.

Question 8

Degree of fragmentation

Answer 8

Species in fragmented habitats may not be able to maintain large enough population sizes. Fragmentation of the forest through deforestation and conversion to plantation forest has led to a reduction of habitat area for the Sumatran rhino in South East Asia.

Question 9

Quality of habitat

Answer 9

Species that live in habitats that are poorer in quality are less likely to survive than species in habitats that better in quality. Human activity can alter the quality of an habitat (agriculture, etc.) therefore making species more prone to extinction.

Question 10

Valued resources

Answer 10

Species that are valued for parts of their bodies are vulnerable to hunting and overexploitation. Ivory from elephants, bush meat from large primates, oil from sperm whales and desirable feathers from birds have all added to the vulnerability
of those species.