why is biodiversity important? - willis'...
TRANSCRIPT
Why is Biodiversity Important?
Species
Richness:
How many
species are in an
area
Why Maintain Diversity?
Ecosystem Services!
Oxygen creation
(phytoplankton)
To reduce floods and erosion
(vegetation)
To generate fertile soil…
To pollinate…
To cycle nutrients…
Bleeding Tooth
Fungus
To control agricultural pests!
Why We Need Species?
Economic Goods!
Why We Need Species?Sources of Food
Aspirin Codeine
Why We Need Species?Sources of Medicines
Provide us with recreation
Ecotourism: giving $$ to a country to view their environment.
Why We Need Species?
# of Species?
• 1.3 million catalogued
• ≈ 8.7 ± 1.3 mill
–Undiscovered: insects, fungi,
bacteria
• 1973 -illegal to import or trade products of E.S.
unless used for science (USFWS)
• Species on list cannot be “taken”, threatened,
killed, harmed: habitat can’t be harmed
Threatened Species
Species has few individuals and is
near becoming endangered.
Gelada Baboon
Grizzly Bear
Northern Spotted Owl
• Threatened-US ESA Habitat loss in Canada and No. US!
• Need old growth forest, top predators, and are specialists.
Species has fewer individuals; at risk
of becoming extinct.
Endangered Species
White Abalone
Barred Bandicoot
Case Study: California Condor• Scavenger bird;
eats dead
carcasses.
• 2005 = 273
individs.
• Endangered: low
birth rates, late
sexual maturity,
poaching, lead
poisoning, DDT,
and power lines.
X Ray shows bottle caps and
metal shards
Intrinsic Characteristics of E. S.
• Extremely localized/require LARGE territory
• Low birth rates
• Island species/extreme specialists
• Low adaptability
• Late sexual maturity
Species no longer exists on Earth.
1,138 documented today since 1600
Extinct Species
Tecopa Pupfish, CA
Yangtze River Dolphin• AKA Bajii
• Last sighting 2004
• Causes: heavy transportation on
river, overfishing,
dams, collision w/ boats, H2O
pollution.
Case Study: Passenger Pigeon• 200 yrs ago 3-5
billion
–world’s most abundant bird
–1 flock =10 mi wide, 100 mi long)
• Killed for its meat
• Martha died in 1914.
Types of Extinctions
• Background
extinction: 3-
30 species
die/yr
• Caused by
natural
selection.
• Mass Extinction:
1000’s spcs
die/yr
• Caused by
dramatic env.
change.
• 5-6 so far
• Humans causing
6th ??
• Too many people!
• Weak/no laws
• High consumption rates
Root Causes of Extinction
Humans Cause Extinction
Habitat Loss/ Habitat Fragmentation
Humans Cause Extinction
Hunting/Poaching
Humans Cause Extinction
Overfishing
Humans Cause Extinction
Capture and Sale of Exotics
2.5 million birds
caught illegally / yr
1 bird in store = 10 deaths in
transit
Humans Cause Extinction
Global Climate Change
Introduction of Non-Native Species –species that does not belong in area.
Humans Cause Extinction
Cane Toad Zebra Mussels in Great Lakes
Iceplant at Beach
Non-Natives/Exotics• Cause problems w/ native
species because:
1. Can usually outcompete
natives
2. Eat same food resources
as natives
3. No natural predators in
new area.
4. Reproduce w/ no limits on
growth.
Amer. Bullfrog in
CA
Crayfish in CA
International Laws
• CITES - Convention on the International
Trade of Endangered Species
–Created by IUCN
–Prohibits trade of live specimens or
products of 900 species on list
CITES
• Uses appendices
for classification.
• Appendix 1:
endangered.
• Appendix 2:
threatened.
• An org. can be on
both CITES and US
ESA!
Squirrel Monkey: App II
Ring-Tailed Lemur: App I
IUCN’s
Red List
• Assess
conservation
status of global
species.
• Use Critically
Endangered,
Endangered, and
Vulnerable.
Common Hippo: Vulnerable
Angel Shark: Crit. Endang.
International
Whaling Commission
• Regulates whaling
• Bans on gill-netting, purse seines
• Japan/Finland/Iceland no sign!
Marine Mammal Protection Act
• 1972, All marine mammals are protected • Prohibits "take” of marine mammals in U.S. waters and by U.S. citizens on the high seas