1 Introduction: What Is Ecology ? Chapter 1

2 Outline Overview of Ecology Ecology of Forest Birds Ecology of Bumblebees Forest Nutrient Budgets Vegetation Change: Pollen Records Nature and Scope of Ecology

3 Overview of Ecology Ecology: Study of relationships between organisms and the environment.  Simple definition does not convey the extreme breadth of this discipline. Ecosystem: Includes all organisms living in an area, and the physical environment with which these organisms interact.  Biosphere: Highest level of ecological organization.

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5 Ecology of Forest Birds MacArthur studied ecology of five species of warblers in spruce forests in N.A.  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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11 Warbler Feeding Zones

12 Ecology of Bumblebees Bumblebees live in many cool regions.  Heinrich estimated energy budget of individuals foraging on different flowers and under different temperatures.  Energy Gain / Loss  Energy Intake - Energy Expenditure.

13 Ecology of Bumblebees Field and Laboratory Results  Amount of energy expended during flight was independent of air temperature.  Bees elevated temperature of thorax to stay warm in cool climates.

14 Ecology of Bumblebees

15 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.

16 Forest Nutrient Budgets 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 < 1%.

17 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 Mtns.  Documented large temporal changes to nearby plant communities.

18 Vegetation Change: Pollen Records 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.

19 Vegetation History from Pollen Sediments

20 Nature and Scope of Ecology Ecology: Study of relationships between organisms and the environment.  Wide variety of approaches.  Large temporal and spatial scales.  Field  Lab  Observational  Manipulative

21 Review Overview of Ecology Ecology of Forest Birds Ecology of Bumblebees Forest Nutrient Budgets Vegetation Change: Pollen Records Nature and Scope of Ecology

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