Transcript Biodiversity Loss

“The current extinction rate is now approaching 1,000 times the
background rate and may climb to 10,000 times the background rate
during the next century, if present trends continue. At this rate, one-third
to two-thirds of all species of plants, animals, and other organisms
would be lost during the second half of the next century, a loss that
would easily equal those of past extinctions.” -Peter Raven (1999)
ES 100: Biodiversity Conservation
November 15th, 2006
Announcements:
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Next Wednesday: Field Trip to Ellwood
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10% of course grade:
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Background Research Assignment posted on website
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Do before field trip: will enhance your experience
Sign up for Van Transportation in Section this week
You may complete field trip early, on your own
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1/2 background research assignment, 1/2 field trip assignment
Field trip assignment and directions will be posted on website
tonight.
You must sign release form in section
Last Time: WWF and MPA’s
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WWF: “draws circles”; tries to conserve
biodiversity
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Today: How do ecologists ‘draw circles’ (decide that
one area is more important than another)
Highlighted importance of social factors that
shape the success of MPA’s
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Today: Another social component is the awareness
and acceptance of intrinsic changing nature of
communities (and what it means for conservation)
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Succession
Who Wins?
Early vs. Late Succession Species
Early
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shade intolerant
•
nutrient demanding
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short-lived
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poor competitors
Late
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shade tolerant
•
adapted to lower nutrient
conditions
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long-lived
•
good competitors
Who wins in the beginning?
Secondary succession
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space, light, and nutrients are abundant
classic r-selected species (opportunists)
Primary succession
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•
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space and light are abundant
nutrients may not be
N-fixing plants are common
•
convert atmospheric N2 into NH4+
How does succession happen?
Facilitation
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early succession species alter conditions to favor the
growth of late succession species
•
•
N-fixers make soil richer
dune grass stabilizes sand
Acceleration
•late
succession species alter conditions to favor their own
growth and prevent the growth of early succession species
•some
plants produce toxic litter
Predestined Communities?
•
A community is a group of living organisms
that occupy a certain area and interact with
one another.
Clement’s climax community theory
Classic Succession
Clements’ idea of “climax community”
• eventually, a given system reaches a predictable
steady-state
• independent of the early succession community
•
Community predestined by climate?
Mixed Beech-Maple Forest
Oak-Hickory
Oak woodland
Oak forest
Willow shrub
Sumac-Pine
Pine forest
Cattail marsh
Broomsedge
Poplars
Aquatic plants
Aster-Goldenrod
Dune grass
Annual weeds
Swamp
Old field
Sand dune
The Role of Randomness
(aka Stochasticity)
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2 species are equally suited to be next
“successors”
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Outcome is CHANCE (dispersal, weather,
ect.)
What is the relationship between
disturbance and diversity?
c
Diversity
a
b
Disturbance frequency or intensity
Intermediate Disturbance Hypothesis
-Joseph Connell, UCSB, 1978
Fire
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Fire-adapted systems
(Fire in pine forest prevents
hardwoods from establishing)
(Some) Seeds germinate after fire
Why doesn’t So. Cal have nice,
intermediate fires?
Human values/perceptions
Why Is Succession Important?
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Understanding ‘natural’ disturbance recovery can
aid human’s restoration efforts.
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Biotic and Abiotic processes are important
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Management plans must recognize that disturbance
is not intrinsically bad!
Where is damage most prominent?
Conservation International: Biodiversity Hotspots
CI quantified by number of endemic plant species and threat
Assessing Biodiversity
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Indicator species: Species that are present only under
strict environmental conditions
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Can be used to detect healthy/unhealthy ecosystems
Example: steelhead, certain diatoms
Species diversity/richness: number of species in sample
-diversity: number of species within a single habitat type
-diversity: difference in species composition between habitats
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Species evenness: equality of relative abundance
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Unevenness might indicate unhealthy ecosystem
Biodiversity Index
Community
I
II
III
Robin
0.2
0.3
0.25
Relative Abundance
Mallard
Crow
Cardinal
0.2
0.2
0.2
0.07
0.1
0.5
0.25
0.25
0.25
Geese
0.2
0.03
Shannon-Wiener Biodiversity Index
Community
Robin
0.2
0.3
0.25
I
II
III
Relative Abundance
Mallard
Crow
Cardinal
0.2
0.2
0.2
0.07
0.1
0.5
0.25
0.25
0.25
H index
Geese
0.2
0.03
1.61
1.23
1.39
s
H   pi log e pi
i 1
Where:
H = the Shannon-Wiener biodiversity index
pi = proportion of each species in the sample (relative abundance)
loge = the natural log of pi
s = the number of species in the community (species richness)
H(Community II) = -(.3*ln(.3)+.07*ln(.07)+.1*ln(.1)+.5*ln(.5)+.03*ln(.03))
Protection of Species or Habitat?
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Will one protect the other?
Endangered Species Act:
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Attempts to preserve endangered species.
Forbids federal agencies from actions that are:
“likely to jeopardize the continue existence of any
endangered or threatened species or result in the
destruction or modification of their habitat.
Hunting permits…. ect.
Development of federal land
Cost was not considered….
Endangered Species Act:
Species Protection vs. Property Rights
“Shoot, Shovel, and Shut Up”
Pombo Bill: Elimination of “critical habitat”
Passed in House, will go to Senate next
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Pombo's bill, which has some Democratic support in the House, would also require the federal government to compensate a
developer or property owner if land use is restricted as a result of the act.
Moreover, the bill is designed to expedite development decisions by giving federal officials a six-month deadline to determine
whether a proposed project would harm a species protected under the act.
The bill would eliminate the requirement for an independent group of scientists to arbitrate endangered species disputes and put the
secretary of Interior in charge of determining the "best available science" regarding protected species.
One controversial amendment, by Rep. Greg Walden (R-OR), would exempt the use of pesticides from regulation under the
Endangered Species Act for five years. The amendment removes the requirement limiting the use of a pesticide known to kill an
endangered species.
Species Protection
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Minimum Viable Population (MVP)
Inbreeding, genetic drift
Genetic bottleneck
Minimum Viable Area—habitat protection
Most genetic
diversity is
retained
Genetic
bottleneck
-Population loses much of
its genetic diversity from a
population decline
Which Species to Protect?
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Umbrella species
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Flagship species
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Keystone species
Habitat Protection: Reserves
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One large or many small?
Shape?
Connectivity?
SLOSS Debate: Single Large vs. Several Small
Species-area curve
Management implications:
•Small reserves:
area =
species
•As area increases, diminishing returns
To consider:
Genetic exchange
Extinction events
Edge effects
Future Pressures
Cost/Flexibility
Reserves…. Size matters!
Shape Matters too! Cores and Buffers:
Connectivity: Nodes and Corridors
Is connectivity important in MPA’s?
Habitat Conservation
Management Tools
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Conceptual diagrams
Collaboration (with stakeholders, community)
Mathematical/computer models
GIS (Geographic Information Systems)
Remote sensing
Bioassessment
Environmental Impact Reports
The new trend……
Ecosystem Based Management (EBM)
"EBM looks at all the links among living and nonliving
resources, rather than considering single issues in isolation . . .
Instead of developing a management plan for one issue . . ., EBM
focuses on the multiple activities occurring within specific areas
that are defined by ecosystem, rather than political, boundaries."
US Ocean Commission Report, 2004
http://ebm.nceas.ucsb.edu/faq/definition/