F. Endangered species

Meaning of status 1. Extinct is beyond help. 2. Extirpated can only be saved by imports. 3. Endangered is in serious trouble & we must act fast to save these species. 4. Threatened means we have more time before they become endangered. 5. Vulnerable means we need to be concerned in the future.

Causes of endangerment 1. Habitat destruction Once the trees are gone, everything that lived in them is gone as well 2. Overexploitation We are running out of many species of fish. 3. Introduction of exotic species The introduced starling has taken nest sites from many local birds. 4. Disease, pollution, etc. The pond still exists, but now few things can live in it.

2] FACTORS INFLUENCING THE STATUS OF A SPECIES SIZE b) SPECIES RANGE c) INDIVIDUAL RANGE d) DIET e) BIOTIC POTENTIAL f) HUMAN INTERACTIONS

SIZE Larger animals need more food and more space. Both eat a similar diet, BUT one eats much more & so needs to move more to find more food

SPECIES RANGE An animal that is found in only one place is at risk if anything happens to that place. The species with a smaller range is at greater risk than one found everywhere

c) INDIVIDUAL RANGE How far one individual roams to find food, mate, etc. A larger individual range puts the species at greater risk

d) DIET A carnivore is at greater risk because its food may become rare more readily than a herbivore’s food

e) BIOTIC POTENTIAL Birth rate, survival to reproductive age, births per year and births per lifetime are all part of this. Mice breed much faster than buffalo.

f) HUMAN INTERACTIONS Some animals do well around people and some do not. Some are killed from fear.

Some are killed by cars.

Some reduce their range by avoiding humans.

Some are poisoned by pollution or purposely to kill predators.

3. Putting all the factors together Species A: small, large species range, small individual range omnivore, moderate biotic potential, many human interactions Five partly positive & one negative factor. Is Species A at risk?

Species A: grey squirrel Not at all at risk!

Species B: medium size, large species range, medium individual range,omnivore, very high biotic potential, many human interactions Five partly positive & one negative factor. Is Species B at risk?

Species B: Atlantic cod On the edge of extinction

Predictions are not always easy! The grey squirrel / human interactions involve feeding. The Atlantic cod / human interactions involve killing and destroying breeding areas. BUT, in general, the more negative factors, the more likely the species is to be in trouble.

600 sites on Earth designated as places where species are most likely to go extinct in the near future [Dec, 2005] notice, most are tropics, only two are Canadian

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