Welcome to Ecology

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Welcome to Ecology!

• Ecology (Bio 47)Spring 2008Tuesday 1100
  150Thursday 1100 150
• Instructor Mrs. Nancy Wheat
• nwheat_at_hartnell.edu
• Text Ecology Concepts Applications by Manuel
  Molles 4th ed

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Introduction What Is Ecology ?

• Chapter 1

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Outline

• Overview of Ecology
• Ecology of Forest Birds
• Forest Nutrient Budgets
• Vegetation Change Pollen Records
• Nature and Scope of Ecology

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Overview of Ecology

• Ecology Study of relationships between organisms
  and the environment.
• Simple definition does not convey the extreme
  breadth of this discipline.

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Overview of Ecology

• Ecology can be studied on many levels.
• Individual
• Behavioral ecology, physiological ecology
• Population Groups of individuals from a single
  species which can potentially interbreed.
• Community All of the populations of all of the
  species in an area.

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Overview of Ecology

• Ecosystem Includes all organisms living in an
  area, and the physical environment with which
  these organisms interact.
• Landscape Includes exchange of materials
  organisms between ecosystems.
• Biosphere Highest level of ecological
  organization.

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Ecology of Forest Birds

• MacArthur studied ecology of five species of
  warblers in spruce forests in North America.
• Theory predicted two species with identical
  ecological requirements could not coexist
  indefinitely.
• Studies found warblers coexisted by feeding in
  different zones of the same tree.

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Warbler Feeding Zones
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What happens when some species are absent?

• Morse expanded MacArthurs study
• Black-throated green warbler had the same feeding
  zone in the two study areas.
• Yellow-rumped warblers moved their feeding zone
  upward when black-throated green warblers were
  absent.
• Morse observed aggressive interactions between
  the two species.

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Forest Nutrient Budgets

• Ecology can also be studied on a much broader
  scale.
• Nutrient budgets in a forest are important to
  understand how this ecosystem functions.

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Forest Nutrient Budgets

• Due to heavy rainfall, many rainforest soils are
  nutrient-poor.
• Nutrient stores in rainforest canopies are
  associated with epiphytes.
• Epiphyte mats contain significant quantities of
  nutrients.
• Trees send roots up to epiphyte mats to access
  nutrients.

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Hubbard Brook Experimental Forest

• Likens and Bormann estimated 90 of nutrients in
  a New Hampshire forest were locked up in soil
  organic matter.
• Approximately 9.5 was tied up in vegetation.
• Streamflow output amounted to lt 1.

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Hubbard Brook Experimental Forest

• Plant growth was suppressed with herbicides for 3
  years.
• Nutrient loss from the deforested basin was
  dramatically higher.

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Vegetation Change Pollen Records

• Many environmental changes occur over large
  spatial or temporal scales.
• Davis monitored plant pollen deposited in lake
  sediments in the Appalachian Mountains.
• Documented large temporal changes to nearby plant
  communities.

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Vegetation History from Pollen Sediments
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Vegetation Change Theoretical Models

• Milne modeled transitions between ecosystems
  (ecotones) as phase transitions.
• Searched for edges between critical densities of
  vegetation along ecotones.
• Suggested areas of gradual change within a
  landscape are most likely to contain biological
  responses to environmental changes.

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Nature and Scope of Ecology

• Ecology Study of relationships between organisms
  and the environment.
• Wide variety of approaches.
• Large range of temporal and spatial scales.
• Field
• Lab
• Observational
• Manipulative