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Conservation Biology • Goal-oriented science that seeks to counter the
current rapid decrease in biodiversity • “The Biodiversity crisis”- human activities alter
ecosystem processes, alter landscape and trigger extinctions. The 6th great extinction
Benefits of diversity • Biophilia- innate connection to nature and life • Anthrocentric
– Species are a natural resource for food, fibers, medicines, etc. – Do all species have an innate value? Are some worth more than others?
Who decides? – Ecosystem services
• Often overlooked benefits to humans: Air, water, soil, detoxification, decomposition, pollination, seed dispersal, nutrient cycling, protection from UV, moderation of weather…aesthetic beauty and infinite source of wonder
• Estimated at $33 trillion/year (1997)- 2x global GNP
– Other studies estimate at only 5-10 trillion dollars
– Economic benefits of biodiversity exceed costs of conservation by 100:1
• The big conclusion from the study: – Environmental 'externalities' - economists' term for benefits from
resources that belong to no one in particular and so are enjoyed for free- are relatively huge. We should do something to account for them in environmental regulations. What is the cost to NOT protecting the environment?
Three Levels of biodiversity
• Genetic diversity • Species diversity • Habitat / community
diversity
Three Levels of biodiversity
1. Genetic diversity – Variation within and between
populations – Genetic diversity allows for
adaptation to changing conditions – If populations loose genetic
diversity they loose adaptive ability – Once genetic diversity is lost it
takes evolutionary time to get it back
Three Levels of biodiversity
2. Species diversity – Loss of species richness – 13% of 9,040 bird species threatened – 47% of all plants worldwide may be
threatened – 20% of freshwater fish extinct of
threatened – Since 1900, 123 extinct freshwater
vert and inverts in North America – Many animals are in the Hundred
Heartbeats club
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Three Levels of biodiversity
3. Habitat / community diversity
– Extinction of one species could have negative impact on others in the system
– Each system can have an important impact on the whole biosphere
– Links are hard to study and harder to predict.
Four Five major threats to biodiversity 1. Habitat destruction 2. Introduced species 3. Overexploitation 4. Disruption of food chains 5. Climate Change
Biodiversity “Hotspots” • 1,500+ species, 70%+ habitat loss • Plant-centric, but account for ~60% of animal species
Five major threats to biodiversity
1. Habitat destruction • Single greatest threat to biodiversity • Over 70% of extinct, endangered, threatened species
from loss of habitat • 93% of reefs are damaged- 1/3 of fish species are in
coral reefs which make up only 0.2% of ocean. • Large variety of human uses impact habitat loss
• Living, food, recreation, materials, fuels, etc…
• Landscape fragmentation • Habitat size is not the only issue, contiguous pieces are also
important
Habitat fragmentation
Edge Effects -diff species -temp -water -wind -fire
Five major threats to biodiversity
2. Introduced species • Second biggest problem- linked to 40% of extinctions • “Exotic species”- species humans have moved from
one location to another, sometime intentionally, sometimes not
• Successful exotics often disrupt their new community, prey on and/or compete with native species
• 50, 000 in U.S. alone, damage control = $130 billion • Some examples…
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Carcinus maenas- Green Crab
• First collected on west coast in S.F.- 1989 • Moved to Bodega Bay by 1993 • Found in Monterey by 1994
Five major threats to biodiversity 3. Overexploitation
– Human harvesting of plants and animals exceeds ability of populations to rebound
– Species especially susceptible are those with low reproductive rates
– The “inexhaustible seas”
MBA Seafood Watch www.mbayaq.org/cr/seafoodwatch.asp
Five major threats to biodiversity 4. Disruption of food
chains • Loss of one species in an
ecosystem can have negative impacts on there species
• Remove the prey, the predators will suffer
• Loss of Keystone species • Since most organism do not
depend on just a single prey species, this can be a very difficult thing to quantify
* The Fifth Major Threat
• Human influenced climate and ocean change
• A changing climate will drive all of the previous threats, and add in others
Sea Level Rise
Not from Sea Ice melt!
From thermal expansion and melting of land-based ice
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The Acid Ocean • While we worry over atmospheric
climate change, the real crisis of the 21st century will probably be in the Ocean.
• The battlefield of that crisis is the Pacific, and Monterey Bay is Ground Zero.
• What will be the ecology of the acid ocean? How will the food chain be altered? What management practices will need to be changed?
Ocean Acidification
Additional stresses for animals that are already food-limited – “Living on the edge”
The oceans absorb most of our CO2 emissions
When CO2 dissolves into the water it form Carbonic Acid.
pH variation in the Pacific Ocean
Data from Jim Barry, MBARI
Sinking O
rganic Debris
Future Ocean Food Web – Loss of biodiversity, low productivity, dominated by microbial recycling?
Microbial R
emineralization
Primary Producers
Zooplankton food web Upper Trophic levels
Seafloor community
Simplified Food Web, Increased Microbial Dominance
What are the expected effects of An acidified Ocean?
Recovery from Disturbance Restoration Ecology
• Restoration ecology is the study of recuperating degraded, damaged or destroyed ecosystems through active human intervention – current extinction rate are 1000 to 10,000 times the ‘normal’ rate
(E.O. Wilson 1988) • The fundamental difference between conservation biology
and restoration ecology lies in their philosophical approaches to the same problem: – Conservation biology attempts to preserve and maintain existing
habitat and biodiversity. – In contrast, Restoration ecology assumes that environmental
degradation and population declines are somewhat reversible processes. Therefore, targeted human intervention can lead to habitat and biodiversity recovery and eventual gains
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• restore a natural disturbance • hastening natural successional
trajectories • increase the effective size of a habitat by
simply adding area or by planting habitat corridors that link two isolated fragments
• monitoring and management are crucial for the long-term stability
• working toward a single desired stable state
The goal of restoration is not to immediately recreate replacement ecosystems, rather to “jump-start” natural recuperative processes.
Environmental Issues • Human impacts on
nutrient cycling • Combustion
byproducts • Increasing levels of
CO2 • Pesticide and fertilizer
issues
• Climate Change • Loss of biodiversity • Habitat loss • Overexploitation • Introduced species • etc., etc., etc…
What will you do to make a difference?
Shameless Plug:
Biol 31- Environmental Science