Transcript Kelp forests - University of Arizona

cartoon
Activity: Should we drill in the Artic National
Wildlife Refuge?
pretty picture
Comparison of ANWR to Continental
US
Map
Predators
Pictures
Snow geese
Porcupine caribou
Vegetation
Muskoxen
Oil
Oil consumption
A Country’s wealth
• Material
• Cultural
• Biological
The value of biodiversity
• Intrinsic value
– American spend $18.2 billion to watch wildlife (vs.
5.8 billion on movie tickets and $5.9 billion on
professional sporting events)
• Economic value
– Wildlife tourism generates $30 billion worldwide
each year
• Male lion living to 7 years old in Kenya $500,000
• Elephant living to 60 years old in Kenya - $1
million
• Coral reefs off Florida – $1.6 billion/year
What do tropical forests provide? The
economics!
• 50-90% of world’s species
• ½ world’s supply of
coffee
– Hardwood
– Food products
like coffee, tea,
cocoa, spices,
nuts, fruits,
natural rubber,
resins, dyes,
oils.
bananas
Medicines
• Active ingredients for 25% of all
prescription drugs are derived from
plants, most of which are in tropical
forest.
• Drugs with active ingredients from these
plants generate $100 billion/year
worldwide ($15.5 billion/ year in US)
• 70% of plant derived cancer-fighting
drugs
Example: rosy periwinkle
• From Madagascar
• childhood leukemia and
Hodgkin's disease.
Drugs from frog skins
• Painkiller hundreds of times more
potent than morphine
• New class of powerful and versatile
antibiotics
• Cancer-detecting hormone
• And less than 5% of all frogs have been
investigated.
Examples
Gastric brooding frog
Broads in young in its
stomach. Applications to
treating stomach ailments?
African clawed frog.
Antimicrobial compound
that disinfects everything
it touches
Sustainable use of rainforests
• Sustainable harvesting of these food
products over 50 years would produce
– 2 times as much $ as timber production
– 3 times as much $ as conversion to cattle
ranching.
Why is tropical deforestation going on?
Why is tropical deforestation going on?
• Related to population growth, poverty,
government policies
• Road-building
– Increases accessibility
• Clearing
– Farming
– Cattle ranching
• Mining and drilling for oil
• Logging – wood and firewood
• Increased susceptibility to fires
Species extinctions
• To survive and be successul, populations
must have:
– Critical population density
– Minimum viable population size
• Background extinctions
– A certain level of species extinction is
normal.
– Populations that do not survive
environmental changes will go extinct.
Extinctions in the horse lineage
Past extinctions in the fossil record
• Mass extinctions
– Many, many species become extinct
simultaneously
• Causes
– Climate change
– Volcanic eruptions
– Disease
– Extraterrestrial impacts
Some of the biggest extinctions
• Over what time periods?
• 225 million years ago
>90% of all species
• 65 million years ago
50% of all species
Fig/ mass extinctions
Lessons from the fossil record
• Extinctions are irreversible
– Usually followed by a period of adaptive
radiation – diversity of life increased,
– but different species evolved.
• Recovery time may be > 10 million
years
Current extinctions
• 20% by 2022, 50% by 2042
• Loss of species due to human impacts
– Difficult to determine how many, which
ones
Estimates using small-scale field
data
• Annual loss of tropical forest habitat
1.8%
• = 0.5% species loss
If there are 5 million species - 25,000
species/year
If there are 20 million species – 100,000
species/year
If there are 100 million species – 500,000
species/year.
Threats to biodiversity
1. Habitat loss
• Deforestation – tropical and temperate
• Wetland loss
• Coral reef destruction
Example: Deforestation in Brazil
Example: Deforestation in Brazil
2. Habitat fragmentation
• Often accompanies habitat loss
• Division of formerly continuous landscape
into smaller, often isolated pieces
• Edge effects
– Invasion by exotics
– Hotter, drier, windier conditions
– Proximity to humans
• Smaller area
– Large carnivores need large areas
3. Exotic species
• Introduced, non-native species
• Out-compete/exclude native species
• Often, no predators in new environment
Example: Purple loosestrife
• Replaces cattails,
willows, horsetails,
other plants
• Eliminates food and
cover for ducks, geese,
muskrats, mink, bog
turtle, sandhill cranes,
others
• Manual control
unsuccessful.
• Now trying biological
control with introduced
beetles
4. Hunting
4. Hunting
• Decreases population size
• Can remove top predator or keystone
species
Example: Northern right whale
• Hunted because
– Easy to find
– Slow
– Lots of oil
• Hunting reduced
population by 97% to
600 individuals
• Protected in 1949,
now threatened by
habitat degradation
5. Environmental degradation
5. Environmental degradation
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•
•
•
Air pollution
Water pollution
Noise and light pollution
Climate change
– Warming, precipitation
• Land degradation
– Erosion from deforestation, poor farming practices
– Removes nutrient-rich top-soil
– Dumps sediment into rivers and lakes
Example: Sea turtles
• Come on shore to
lay eggs.
• Disturbed by bright
lights, tend to
choose darker
beaches.
• Hatchlings are
confused by lights,
head in the wrong
direction.