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 10-20 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 for forestry, farming, fishing, recreation, energy

At Risk Species 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 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 1930s 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