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Bird Trip: Email Me
Sunday April 29 or May 6? Need binoculars? Transportation?
Outline
• Community Ecology
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–
–
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Indirect effects, Keystone species, Invasive species
Biodiversity: importance and evaluation
The new paradigm in ecology: communities in flux
Conservation of species interactions
• Ecosystem Ecology
– Ecosystem services
– Biodiversity and ecosystem services
– Ecosystems of special concern (Marine and Tropical)
Purple Loosestrife
• Benefits of Biological
Control
– Mediate spread
– Restore interactions
– Conserve endangered
species
• Risks of Biological
Control
– Unintended ecological
consequences
How Risky is Biological
Control?
• 800 spp. of snails have
evolved in Hawaii
islands.
• Rosy Wolf-Snail
introduced to control
Giant African Snail.
• 50-75% of native land
snails extinct.
Simberloff, D., and P. Stiling. 1996. How risky is biological control? Ecology 77:1965-1974.
Gypsy Moths:
Entomophaga maimaiga
Island Communities
• Some of the “best” examples
of invasive species come
from island communities
– Brown tree snake on Guam
– Rosy wolf-snail in Hawaii
• Possible reasons
– Low Diversity (1° factor:
discuss later)
– Relaxed selection (2°
consequence of low diversity)
Biodiversity
(1)
(2)
(3)
Biodiversity
Richness
Simpson’s
Shannon-Wiener
Endemicity
6
1.35
2.67
1
5
1.35
7.58
0
4
1.38
4
2
*In nature, different “diversity indices” typically give similar results
Biodiversity
Richness: Total number of spp.
Evenness: The distribution of individuals among spp.
How do we determine species richness?
BIOBLITZ:http://www.smithsonianmag.si.edu/smithsonian/issues00/apr00/interest_apr00.html
Total species found in 695 acres over 24 hours - 1,369
Measuring Biodiversity:
Extrapolation
• ~ 1200 beetle spp. in canopy of
Luehea seemanii.
• ~ 13.5 % (163 spp.) of beetles are
specialists.
• ~ 50,000 tropical tree spp.
• Beetles ~ 40% of insect diversity.
• ~ 2/3 insects found in canopy, 1/3
on ground
• ~30 million insect spp.
Measuring Biodiversity: Estimators
Species
For more info, see: Colwell, R. K., and J. A. Coddington. 1994. Estimating
terrestrial biodiversity through extrapolation. Phil.Trans.R.Soc.Lond.B. 345:
101-118.
Goal: sample here, extrapolate there
Samples
NOTE: Species richness increase with sampling effort
ALAS
“How many arthropod species are there in a tropical rainforest? . . .
Systematists use a "find them all" approach . . . Community ecologists,
in contrast, use a "sample and estimate" approach. Project ALAS
combines both traditions in an assessment of arthropod diversity.
"Sample and estimate" methods are used to sample a set of broad
"survey taxa," while "find them all" methods are used to sample much
more thoroughly a set of smaller "focal taxa." The known focal taxa are
then used to calibrate and evaluate and compare the sampling and
estimation methods.”
http://viceroy.eeb.uconn.edu/ALAS/ALAS.html
Is Biodiversity Important?
• Conservation Biology Perspective
– Inherently valuable
• Utilitarian Perspective
– Natural resources: Genetic libraries; natural design
• Ecological Role
– Invasibility
– Stability
– Ecosystem Function