Bird Trip: Email Me

Sunday April 29 or May 6? Need binoculars? Transportation?

Outline

• Community Ecology– 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

6 1.35 2.67 1

5 1.35 7.58 0

4 1.38 4 2

Richnes

s

Shannon-W

ienerSimpson’

s Endemicit

y

*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: EstimatorsFor 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.

Samples

Spec

ies

NOTE: Species richness increase with sampling effort

Goal: sample here, extrapolate there

ALAS

http://viceroy.eeb.uconn.edu/ALAS/ALAS.html

“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.”

Is Biodiversity Important?

• Conservation Biology Perspective– Inherently valuable

• Utilitarian Perspective– Natural resources: Genetic libraries; natural design

• Ecological Role– Invasibility– Stability– Ecosystem Function