Overexploitation

Overexploitation

Tokyo Tuna Market

Commercial exploitation

Morel Mushrooms for Sale

Coral harvested for jewelry

Rhinoceros exploitation

Rhino hornProducts – Dagger marketin Yemen

Rhino Horn in Traditional Medicine

Wild Blueberries

Wild Salmon

Egret plumes and feathered hat

Tragedy of the Commons

Japanese Whaling Ships

Subsistence exploitation

Subsistence Hunting

Recreational exploitation

Hunting as Recreation

Shell Collection

Gordon Alcorn

Photographic safari

Cheetah on Land Rover

Incidental exploitation

Kemp’s Ridley Sea Turtle

Trawling

Shrimp net with TED – turtle exclusion device

Indirect exploitation

Domestic cats preying on small birds

Pet market

Tropical Fish for Aquarium Trade

Cactus Market

Saguaro Cactus

Consequences of Overexploitation

1. Population Effects- Reduction in population size- Age structure- Sex ratio- Genetic structure

2. Ecosystem Effects

Age Structure: A – fish in typical populationB – fish taken by fishing

Sex Ratios – The Fisher

Fisher Distribution

Genetic Structure – Coho Salmon

Genetic Structure – Coho Salmon

Ecosystem Structure – Loss of Large Trees

Planting Sequoias

Giant Redwood

Redwood Forest in the Air

Ecosystem Structure – Loss of Snags

Loss of Keystone Species - Sea Otter with Sea Urchin

Loss of Keystone Species - Glyptodont

Exotic Species

Mrs. Black Horse, Cheyenne Nation, and dog travois

American Chestnut

Cracking From Chestnut Blight

Exotic Species• Conservation biologists typically call

introduced species “exotic species” - species which live outside their natural range

• Botanists typically refer to exotic plants as alien species

• Other terms you may see include biological invaders, introduced species, invasive species, non-indigenous species, non-native species (my preferred term)

How Do Exotic Species Get Dispersed?

1. Stowaways2. Subsistence and Commerce3. Recreation4. Whimsy or aesthetics5. Science6. Biological Control

Norway Rat as ship rat

Earthworms and pre-exotic distribution

Cars transport seeds via mud stuck to car

Ballast Water Discharge

Commerce and Subsistence

Commerce and Subsistence

Monterey Pine

Blue Gum Eucalyptus

Feral Pig - Florida