1. Ch 11 Habitat Loss/ Invasives
Section 03
Section 04

2. C. HABITAT LOSS, DEGRADATION, AND FRAGMENTATION
Conservation biologists summarize the most important causes of premature extinction as “HIPPO”:
Habitat destruction, degradation, and fragmentation
Invasive species
Population growth
Pollution
Overharvest

3. Habitat fragmentation leads to species vulnerability to predators, disease
One in six species of birds are threatened with extinction due to habitat loss and fragmentation
Nonnative species are the 2nd greatest threat to birds
Species are limited in their ability to colonize new areas, find mates and food

4. Mountain Lion Habitat Fragmentation
The map shows Fragmented Local Forest in Southern California
Why would a Mountain Lion attack Humans?
PLAY
NEWS VIDEO

5. Commercial hunting and poaching Habitat degradation and fragmentation
Habitatloss
Overfishing
Pollution
Commercial hunting and poaching
Habitat degradation
and fragmentation
Climate change
Introducingnonnative species
Sale of exotic petsand decorative plants
Predator and pest control
Secondary Causes
• Population growth
• Rising resource use
• No environmental accounting
• Poverty
Figure 11.7
Natural capital degradation: underlying and direct causes of depletion and premature extinction of wild species. The major direct cause of wildlife depletion and premature extinction is habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems.
Basic Causes
Fig. 11-7, p. 229

6. Birds are excellent environmental indicators because they live in every climate and are easily tracked
Birds help to control rodents and insects, pollination of flowering plants, seed dispersal

7. Case Study: A Disturbing Message from the Birds
The majority of the world’s bird species are found in South America.
Threatened with habitat loss and invasive species.
Figure 11-10

8. INVASIVE SPECIES
Many nonnative species provide us with food, medicine, and other benefits but a a few can wipe out native species, disrupt ecosystems, and cause large economic losses.
Show news report video on kudzu
Kudzu vine was introduced in the southeastern 1930’s U.S. to control erosion. It has taken over native species habitats.
Figure 11-A

9. INVASIVE SPECIES
Many invasive species have been introduced unintentionally.
Figure 11-11

10. SEA LAMPREY
It is thought that improvements to the Welland Canal in 1919 allowed its spread from Lake Ontario to Lake Erie, and while it was never abundant in either lake, it soon spread to Lake Michigan, Lake Huron, and Lake Superior, where it decimated indigenous fish population in the 1930s and 1940s
Sealamprey are parasites they will eventually kill the trout.

11. Asian Long-horned Beetle
Believed to have been brought over in the wood of crates
Trees favored by the Asian Longhorned Beetle are predominantly maples
Currently, there is no known chemical or biological defense against the Asian Longhorned Beetle and, in North America, they have few natural predators.
The damage is caused by beetle larvae which burrow deep within a tree to feed on its food and water conducting vessels.ﾊ Continued feeding causes structural defects and eventually kills the life-sustaining cambial layer by girdling.ﾊ Mature beetles then burrow out of the tree leaving holes the diameter of ball-point pens.ﾊ Heavy Asian Longhorned Beetle infestations can kill otherwise healthy adult trees.

12. Show the video on how africanized bees where introduced to the americas.
Threats to natural capital: some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States.
Fig , p. 234

13. They have no natural predators, competitors, or pathogens in their new habitat
They can trigger ecological disruptions, such as the wild African honeybee
Some have become genetically resistant to pesticides through natural selection

14. INVASIVE SPECIES
The Argentina fire ant was introduced to Mobile, Alabama in 1932 from South America.
Most probably from ships.
Aggressive nonnative species that has eliminated about 90% of native ant species.
Figure 11-12

15. FIRE ANT ATTACK! PLAY YOUTUBE VIDEO
Have video of fire ants taking away larvae from other colonies.
PLAY
YOUTUBE VIDEO

16. INVASIVE SPECIES
Prevention is the best way to reduce threats from invasive species, because once they arrive it is almost impossible to slow their spread.
Figure 11-13

17. Ecosystems Vulnerable
Characteristics of
Successful
Invader Species
Characteristics of
Ecosystems Vulnerable
to Invader Species
• High reproductive rate,
short generation time
(r-selected species)
• Pioneer species
• Long lived
• High dispersal rate
• Release growth-inhibiting
chemicals into soil
• Generalists
• High genetic variability
• Climate similar to habitat of invader
• Absence of predators on invading species
• Early successional
systems
• Low diversity of native species
• Absence of fire
• Disturbed by human activities
Figure 11.13
Threats to natural capital: some general characteristics of successful invasive species and ecosystems vulnerable to invading species.
Fig , p. 236