Community%20Ecology%20-%20Module%205

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Community Ecology - Module 5

• Dr. James Danoff-Burg
• Columbia University

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Community Ecology

• Next step up the ecological hierarchy from
  populations
• Definition A population of species co-occurring
  populations
• Together, they comprise the biotic component of
  the ecosystem

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Community Function

• More than a Collective properties of participant
  species
• Emergent properties
• ecosystem stability
• limits to similarity of competing species

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Community Drama Players

• Producers (Module 6)
• Primarily plants and bacteria
• Consumers (Module 7)
• Herbivores, Predators, Parasites, Parasitoids,
  Mutualists
• Decomposers (Module 8)
• Vertebrates, Invertebrates, Fungi, Bacteria

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Community Features

• Richness
• Abundance
• Diversity
• Evenness
• Community Similarity
• Trophic Levels
• Feeding Guilds
• Endemism
• Vertical Structure

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Community Features

• Richness
• number of species
• Abundance
• number of individuals
• either per species or gross abundance

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Richness and Abundance

• Most commonly used features of community for
  summarizing
• Most intuitive
• BUT
• Could provide misleading results
• Why?

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Problems w/ Richness Abundance

• Edge species are often invasive/exotic,
  anthropophilic, and are everywhere
• May lead people to conserve areas that are less
  important
• Do not take into account endemicity

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Other Community Features

• Trophic Levels
• Feeding Guilds
• Evenness of species
• Community Similarities
• Vertical Horizontal Structuring
• Diversity (next most commonly used)

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Diversity Indices

• Definition
• Combination of richness abundance, combine
  these data in different fashions
• Information Theory based (assessing certainty of
  sampling all species present)
• Sensitivities
• Unevenness in abundance often leads to strange
  results (e.g., deer herbivory study)
• Unequal collecting effort

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Diversity Indices

• Methodology
• enter data, calculate indices
• general comparison of relative sizes
• some advocate for parametric statistics
• Common Indices
• Shannon-Wiener
• Simpson
• Brilluoin
• Fishers alpha

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Todays Activity - Brazil

• What is the influence of plant biodiversity in
  home gardens on that of beneficial and harmful
  insects?
• Could advocate for intercropping, a more
  sustainable form of farming

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Methods

• Sample insects using pan traps (water, salt,
  soap)
• Use three home gardens of different overall plant
  biodiversity

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Methods II

• Remove insects from pan traps
• Isolate parasitoids
• Isolate homopterans
• Sort both to morphospecies
• Total richness and abundance
• Input into computer program
• Calculate diversity indices

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Methods III

• Compare plots to each other
• Make bar graphs of values and indices
• Use photos sites, process, and animals
• Write up a paper of the class
• Use PowerPoint
• Football at 530