Sustaining Biodiversity: The Species Approach

Josh Li, Mike Smith, and Jay Zhou

Biological Extinction: The disappearance of a species from Earth

Background Extinction: Continuous, low level of extinction of species over 3.65 billion years

Mass Extinction: Loss of many species in a short period of time

Extinction Rate: Percentage or number of species that go extinct each year

Key Terms

● Human activities increase the pace of extinction

● Since the arrival of humans, background extinction rates have increased 100-1000 times (currently 0.01- 0.1% per year)

● Extinction rates are estimated to rise to ~1% per year by the end of the century, causing ¼ to ½ of species to become extinct

● Biodiverse hotspots (estuaries, rainforests) are being degraded, reducing the emergence of new species

Humans’ Role in Species Extinction

Endangered Species: Few individual survivors that may soon become extinct over its indigenous range

● Ex: Black rhino, blue whale, giant panda

Threatened/Vulnerable Species: Still abundant in its natural range, but soon to become endangered

● Ex: Great white shark, marine iguana, polar bear

Near-Extinct Classifications

● Species are vital to Earth’s life support system

● Support our economy by providing ecotourism and components of various products and medicines (cancer drugs)

● It will take millions of years to rebuild biodiversity

● Species have a moral right to exist, regardless of their usefulness

Reasons to Prevent Species Extinction

Pacific yew: Used to treat Ovarian Cancer

● HIPPCO describes premature extinction of species: Habitat destruction/fragmentation, invasive species, population and resource use growth, pollution, climate change, and overexploitation

● Loss of wetlands, clearing of rainforests, and plowing of grasslands are extremely detrimental to biodiverse ecosystems

● Habitat fragmentation is the division of large, contiguous habitats into isolated patches

How Humans Accelerate Species Extinction

● Non-native species, whether accidental or deliberate, often threaten or endanger native species○ They have no natural predators and can trigger ecological disruptions

● Overpopulation and overconsumption of resources can eliminate habitats

● Pollution from chemicals such as pesticides can damage small ecosystems. Human pollution also causes climate change, which causes habitat loss

● Global demand for vulnerable/endangered species as food or pets has increased poaching, which lowers biodiversity

HIPPCO cont.

● Treaties such as the 1975 Convention on International Trade in Endangered Species protect 900 species from commercial trading and restricts trading of 29,000 species○ Unfortunately difficult to enforce and many nations did not

sign

● A sanctuary approach can be used to protect wildlife; 548 federal refuges exist, but habitats require more funding

● Gene banks, botanical gardens, farms, aquariums and zoos can be used to support species until they are ready for reintroduction into the wild

Protecting Species from Extinction

● Generally, the safest approach is to use the precautionary principle

● If there’s evidence that an activity harms human health or the environment, we should take measures to reduce or prevent the damage

Precautionary Principle