Lectures 24 & 25
Conservation Biology
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Conservation Biology –
The scientific study devoted to the preservation of earth’s biodiversity
Our Biodiversity Crisis
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We are in the midst of the sixth mass extinction on earth.
The culprit?
- us
Biodiversity Loss
• Endangered species –
“in danger of extinction throughout all or a significant part of its range”
– Endangered Species Act 1973
Example: California Condor
• Threatened species – are declining; will likely become endangered
Example: Red-legged frog in CA
Why protect Biodiversity?
1. Ethics and Aesthetics
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Intrinsic Value
Beauty
(A bobcat in Yosemite)
2. We need other species!
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Food
Clothing
Shelter
Medicines
Oxygen
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Useful genes
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- the rosy periwinkle (contains 2 substances currently used to treat cancer)
3. Ecosystem Services
– Examples:
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Pollination
Flood prevention
Clean air and water
Threats to Biodiversity:
1. Habitat loss/damage
- logging, development, farming, etc.
Lectures 24 & 25
Conservation Biology
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- Total loss or fragmentation
Edge effects
Fragmentation results in habitat edges
- favors edge-adapted species
- can reduce diversity
(The cowbird, a nest parasite)
2. Invasive species
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non-native
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often eat or outcompete local species
haven’t evolved with local species
Invasive Species
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Bullfrogs in California
Ice plant in Santa Barbara
Kudzu in the Southeastern US
Feral pigs on the Channel Islands
- Introduced by farmers
- Currently threaten ten species, including Channel Islands Fox
3. Over-exploitation
- hunting
- harvesting
(Passenger pigeons: now extinct)
This web site provides useful information about the plight of the Passenger Pigeons:
http://www.stanford.edu/group/stanfordbirds/text/essays/Passenger_Pigeon.html
Over-harvesting of seafood
(examples: Bluefin tuna; Red abalone)
Seafood watch, guidelines from the Monterey Bay Aquarium:
http://www.mbayaq.org/cr/cr_seafoodwatch/download.asp
4. Pollution
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Car exhaust
Factories
Chemical Pesticides
Fertilizers
Lectures 24 & 25
Conservation Biology
Pollution: Biological magnification
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Toxins accumulate as they are passed up the food chain
Top predators are most vulnerable
5. Global warming
Linked to:
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Increase in burning of fossil fuel
Increase in greenhouse gases, especially CO2
Greenhouse Gases
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Trap heat in earth’s atmosphere
• CO2
• Nitrous oxide
• Methane
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Lectures 24 & 25
Conservation Biology
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Effects of Global Climate Change (GCC)
1. Glaciers melting; Increase sea level
2. Species range shifts
- Spruce budworm invades Alaska
- Gelada baboons moving up the mountain in Ethiopia
3. Species resource base changes
(Polar bears losing hunting grounds)
Conservation Priorities
1. Preserve ecosystems or landscapes
- Reduce Fragmentation
- Nature Reserves
- Buffer zones
- Corridors
Wildlife corridor
2. Biodiversity hot spots
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Areas of high endemism and species diversity
The California Floristic Province, where we live, is a Biodiversity Hotspot. There
are over 2,000 endemic species living in this province. For more information about
the California Floristic Province, see this web site:
http://www.biodiversityhotspots.org/xp/hotspots/california_floristic/Pages/default.aspx
Restoration Ecology
• Return degraded areas to their natural state
(Coal Oil Point Reserve)
Sustainable Development:
focus on the long-term health of human societies and the ecosystems that support life