The Importance of Biodiversity The need for biodiversity

The Importance of Biodiversity • The need for biodiversity • Vulnerable, Threatened, Extirpated, Endangered, and Extinct species • Keystone species • Species extinction and biodiversity • Natural and human causes of extinction

Biodiversity • The variety of life in a particular ecosystem. • Measured by counting the number of species in a specific habitat or ecosystem • This measurement is referred to as species richness What is Biodiversity?

Biodiversity • Tropical rainforests have the highest biodiversity of any ecosystem – E. g. The Peruvian rainforest has 283 species of tree in a single hectare while a similar sized forest elsewhere will typically support only 1020 species of tree.

The Social Value of Biodiversity • The human species depends on biodiversity for its survival – Cleans the air we breathe – Recycles and purifies the water we drink – Absorbs waste we produce – Stabilizes and moderates climate

The Economic Value of Biodiversity • Provides enormous economic and community benefits through the use of natural resources forestry, farming, fishing, recreation, energy

At Risk Species who are at risk can be classified as: • • • Vulnerable Threatened Extirpated Endangered Extinct

Vulnerable • Any species that is at risk because of declining numbers. E. g. Grey Fox

Threatened • Any species that is likely to become endangered if the factors that make it vulnerable are not reversed E. g. Peregrine Falcon

Extirpated • Any species that no longer exists in one part of a country, but can be found in others E. g. Grizzly Bear

Endangered • A species that is close to extinction in all parts of a country or in a significantly large area.

Manatees • Due to boat collisions, entanglement in fishing gear and habitat loss, these gentle creatures have become endangered. Endangered Species

Extinct • A species that is not found anywhere Passenger Pigeon Tasmanian tiger

What’s the big deal about the Passenger Pigeon!!!!!

Keystone Species • Keystone Species: Species that have strong interactions with other species and affect their health and survival Keystone Species

Example - Bats

Bats • Bats are considered pests because they can be a nuances and are scary and turn into vampires

• This leads people to kill them and destroy their homes. However, bats eat moths and pollinate flowers. • So areas that have bats removed now have many fewer flowers and have too many moths which destroy crops.

• It is very hard to identify important keystone species until after an ecosystem collapses due to their absence • Animals like the passenger pigeon might seem important after they’re gone but there is no way to get them back.

The Link between Species Extinction and the Biodiversity of Ecosystems • Extinct refers to a species that has died out and no longer exists on Earth • Although it is a natural process that occurs over thousands and millions of years, human activity has drastically increased the rate of extinction

Extinction

Natural Causes of Extinction • • Competition with other organisms Environmental disasters Climate change Shortage of food Low reproduction High number of predators Competition with invading species

• Over the course of history there have been many large scale extinctions that are thought to be linked with natural disasters.

Human Causes of Extinction • • • Invasion of habitat Over hunting Pollution Habitat loss and fragmentation Removing resources Introducing invading species

The Tasmanian Tiger • Despite the name, these animals were stripped marsupials (like kangaroos) not tigers • Native to mainland Australia and Tasmania, they were declared extinct as recently as the 1930 s after a century of intensive hunting

Human Impact on Extinction • Species extinction have risen significantly with the recent human population explosion over the last 200 years

Bill Nye – Biodiversity