1. 3.3 Threats to Biodiversity

2. Habitat Loss (most significant threat to biodiversity) Occurs when events alter an ecosystem so much that many species can no longer survive there.
a) Deforestation
Occurs when forests are logged or cleared for human use and are not replanted.
(see video clip)

3. Often drained for farming, construction or mosquito control.
b) Draining Wetlands
Often drained for farming, construction or mosquito control.
*Note 85% of the wetlands of international importance are threatened, rice cultivation has called 40 million hectares in in India, Thailand, Vietnam and China.

4. 2. Alien Invasive Species (2nd largest threat to biodiversity)
Species introduced to new parts of the biosphere from other regions;
May be introduced on purpose or accidentally in shipments of food or goods.
They take over the habitat of native species.
Arrive, Survive and Thrive.
Examples:
European Earwig
Giant Hogweed.

5. Zebra Mussels
Native to Asia; introduced to the Great lakes through ballast water in the 1980’s
Out-competes native mussels and other organisms that share the same food; impacts other levels in the food chain.

6. Introduced by ballast water in late 80’s.
Round Gobies:
Introduced by ballast water in late 80’s.
Competes with native fish for spawning areas
Eat many aquatic species which affects food chains of native species.
10 years after arrival, found in all 5 great lakes.
Lake Erie population in the billions.

7. 3. Overexploitation
Use or extraction of a resource until it is depleted.
Over fishing of Atlantic cod
Hunting of the passenger pigeon.

8. 4. Disrupting Connectivity Across Ecosystems
When one species is affected in an ecosystem, other ecosystems may be impacted.
e.g. Salmon populations may be connected to the health of temperate rainforests in B.C. Canada.

9. 5. Extinction May happen through: a) Background Extinction:
Caused by slow change to ecosystem over time.
b) Mass Extinction:
occurs quickly
may be caused by humans (e.g. overexploitation) or
by natural causes (e.g. meteorite)
Current extinction rates are x higher than the background extinction rate.
bring-mammoth-dead.html
The death of all the individuals of a species
e.g. dinosaurs

10. Species currently endangered
Glass frog
(Central and South America)
Chinese giant salamander

11. Giant Coconut Crab (Guam and Pacific Islands)
Frigate Island Beetle
Giant Coconut Crab (Guam and Pacific Islands)

12. Canadian Endangered Species
Beluga whales
American Bison
Cougar
Black-footed ferret
Northern Fur Seal
Wolverine
Marmot
+many more ……….

13. Thailand Endangered Species