Chapter 1 Concepts
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Ecology has multiple definitions due to its breadth of study
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Resource Utilization
Ecology has organizational breadth (individuals to biosphere)
Ecology has temporal breadth (seconds to millennia)
Ecology has spatial breadth (millimeters to global)
– Heinrich and Bumblebees
– MacArthur and Forest Birds
Bumblebee energy budgets (Heinrich)
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Estimated energy budgets (intake versus expenditure) of bumblebees in field and lab
Followed bumblebees in the field, quantified visited flowers, nectar gathered, time
flying, time foraging
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Estimated energetic costs of flying in a respirometer (oxygen consumption)
Able to estimate how many flowers a bee must visit to maintain body mass
MacArthur and Forest Birds
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Boreal forest warblers (Fig. 1.2)
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Forest Nutrient Budgets
Feeding zones reduce competition
Confirmation of competitive exclusion by Morse (Fig. 1.3)
– Likens/Bormann nutrient retention
– Nadkarni and epiphytes
Likens and Bormann
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90% of nutrients in deciduous forest soils, only 9.5% in vegetation
Trees cut in one valley, remained in the other (Fig. 1.6)
Export of nutrients in cut valley through the stream increased dramatically in the
three years following deforestation
Nadkarni and epiphytes
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Rainforest soils poor due to leaching of minerals
Nutrients trapped in epiphyte mats (“air” plants)
Trees send “roots” into epiphytes to access nutrients
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Vegetation change
– Davis and pollen
– Milne and ecotones
Davis and Pollen records (Fig. 1.7)
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Studied pollen cores in lakes
Followed changes in presence of species over time (20,000 BP to present)
Changing climate mirrored by changing pollen (warming)
Milne and ecotones
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Studied transition from grassland to forest
When does one become the other?
Narrow ecotones indicate rapid shifts in environmental characteristics
Wide ecotones indicate slower environmental shifts