Transcript PPT
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 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