Invasive Species and Biodiversity Notes

Invasive Species

• Aliens Among Us: Introduction to the topic of invasive species.

Biodiversity

• Definition: The number and variety of life found within a specific region.
• Canadian Biodiversity: Canada is home to thousands of species across various aquatic and terrestrial ecosystems.
  • Plants, insects, fungi, and small invertebrates are more diverse than larger animals.
  • Canadians have a responsibility to protect organisms found only in Canadian ecosystems, such as the Peary caribou.
• Biodiversity Hotspots: Areas with an exceptionally large number of species in a relatively small area.
  • Carolinian Canada and the Georgian Bay Biosphere Reserve are biodiversity hotspots, representing 1% of Canada’s landmass but containing the highest number of species.
• Global Biodiversity Distribution: Biodiversity is typically higher near the equator.
  • Abiotic factors like rainfall and temperature increase biodiversity.
  • The Amazon Rainforest is one of the most biodiverse places in the world.
• Importance of Biodiversity: Areas with higher biodiversity are more stable and healthy.
  • Ecosystems with low biodiversity are more fragile.

Biodiversity Numbers in Canada

The number of known species in Canada for various groups of organisms:

• Amphibians: $42$
• Arachnids: $3275$
• Birds: $426$
• Crustaceans: $3139$
• Fish: $1100$
• Fungi: $11800$
• Insects: $18530$
• Mammals: $194$
• Molluscs: $1500$
• Plants: $4934$
• Reptiles: $42$

Invasive Species and Biodiversity Decrease

• Invasive Species Definition: A non-native species (an organism that does not normally live in the habitat) that arrives in ecosystems typically through human interference.
• Process of Invasion: Native species may not compete well with introduced species.
  • Without natural predators, non-native populations can increase rapidly and become invasive.
  • Invasive species are introduced species with growing populations that spread and negatively affect their environment.

Invasive Species - Case Study: Beavers in South America

• Introduction: Beavers were introduced to South America for fur.
• Problem: Warmer weather prevented fur from thickening, so beavers were not trapped or hunted and populations grew out of control.
• Damage: Beaver dams caused damage to ecosystems.
• Failed Solution: Non-native foxes were introduced to control beavers but preyed on native rabbits instead.
• Result: Lack of rabbit droppings affected soil quality, causing the ecosystem to be out of balance.

Examples of Invasive Species

• Ontario: Gobies in Lake Ontario, Buckthorn plant, Dog-strangling Vine, Asian Carp.
• Florida: Burmese Pythons.
• Australia: Cane Toads, Rabbits.
• United States: Kudzu Vines.

Keystone Species

• Definition: A species so important to the ecosystem that its removal would cause the whole ecosystem to fall apart.
• Types of Keystone Species:
  • Predators
  • Mutualists
  • Ecosystem Engineers