Overexploitation Tokyo Tuna Market. Types of Overexploitation Commercial exploitation Subsistence...

Overexploitation

Tokyo Tuna Market

Types of Overexploitation

• Commercial exploitation

• Subsistence exploitation

• Recreational exploitation

• Incidental exploitation

• Indirect exploitation

• Pet and garden market

Commercial exploitation• Potential market for wild products is enormous

• Given market, people will exploit wild species for financial gain

• Domestic substitutes for wild products are not identical in value

• Market price for wild products increases as product becomes rarer

• Wild resources are communal resources owned by no one or everyone

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 Fishing

Ojibway wild rice harvesting

Recreational exploitation

Hunting as Recreation

Shell Collection

Gordon Alcorn

Photographic safari

Cheetah on Land Rover

Dive boat damage to coral reefs

Incidental exploitation

Trawling

Kemp’s Ridley Sea Turtle

Shrimp net with TED – turtle exclusion device

Indirect exploitation

Overgrazing

Domestic cats preying on small birds

Pet and Garden Market

Gray Parrots in Smuggler’s Crate

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

Giant Redwood

Redwood Forest in the Air

Planting Sequoias

Ecosystem Structure – Loss of Snags

Loss of Keystone Species - Sea Otter with Sea Urchin

Loss of Keystone Species - Glyptodont

Maclura pomifera – Osage Orange

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. Stowaways

2. Subsistence and Commerce

3. Recreation

4. Whimsy or aesthetics

5. Science

6. Biological Control

Norway Rat as ship rat

Earthworms and pre-exotic distribution

Lumbricus terrestris

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

Bighead Carp

Carp Jumping

Recreation - Brown Trout

Ring-necked Pheasant

Chukar

Red Deer – New Zealand

Whimsy or Aesthetics – European Starling

House Sparrow

Exotic plants in New Zealand

• Native flora of 2065 species

• 24,774 documented introduced alien species

• About 2200 exotics have become established (naturalized)

Multiflora Rose

Tree of Heaven - Ailanthus

Light blue – counties where Ailanthus is present

Scotch Broom

Walking Catfish

Cherry Headed Conures in San Francisco

Monk Parrots – Chicago, Harold Washington Park and Hyde Park

Science - Gypsy Moth

Africanized Honey Bees

Movement of Africanized Honey Bees

Movement of Africanized Honey Bees

Biocontrol

Klamath Weed – aka – St. John’s Wort

Chrysolina beetle

Prickly Pear Hedge - Tunisia

Prickly pear in Australia – before control

Cactoblastis cactorum

Prickly pear – same location after control

Red Fox - Australia

With native Bobuck possum

Red fox - Australia