Plant Ecology - Chapter 17 Climate & Physiognomy.
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Transcript of Plant Ecology - Chapter 17 Climate & Physiognomy.
The Abiotic Components of Ecosystems
1) Outside energy source1) Outside energy source
2) Physical factors that determine2) Physical factors that determine weather, climateweather, climate
3) Chemicals essential for life3) Chemicals essential for life
Outside Energy Source
PowersPowersphotosynthesisphotosynthesis
Warms earthWarms earth
Powers waterPowers watercyclecycle
Physical factors that determinePhysical factors that determineweather, climateweather, climate
HeatHeat
WindWind
PrecipitationPrecipitation
TopographyTopography
HeatHeat
Daily temperatures can also vary dramatically in some habitatsDeserts - dry air, loses heat rapidlyHigh altitudes - thinner “blanket” of atmosphere
HeatHeat
Long-term changes in earth’s orbit, positionCollectively produce Croll-Milankovic effects on climateOrbit shape changeAffects range of seasonal variation
HeatHeat
Direction of the tilt - the “wobble”Changes which hemisphere is pointed toward sun when orbit is closest to sunAffects severity of seasonal shift
Wind and PrecipitationWind and PrecipitationUneven heatingUneven heating
Ascending, Ascending, descending air descending air masses - masses - Hadley Hadley cellcell
Slide 13Slide 13Slide 13Slide 13Slide 13
Moist surface warmed by sun
Flows toward low pressure,picks up moisture and heat
Warm,dry air
Hot, wetair
Falls, is compressed, warms Rises, expands, cools
Heat releasedradiates to space
LOWPRESSURE
HIGHPRESSURE
Cool, dryair
Condensationand
precipitation
HIGHPRESSURE
HIGHPRESSURE
LOWPRESSURE
LOWPRESSURE
Figure 6-10Page 117
ModifiersModifiers
Rotation of Rotation of the globe - the globe - Coriolis Coriolis effecteffect
Hadley, Hadley, Ferrel cells, Ferrel cells, jet streamsjet streams
ModifiersModifiers
Ocean Ocean currents, currents, gyres gyres induced by induced by surface air surface air mass mass movementmovementss
ModifiersModifiers
TopographTopography - lakesy - lakes
Lake effect Lake effect precipitatiprecipitationon
Multi-year PatternsMulti-year Patterns
Combined Combined ocean ocean currents currents and jet and jet streamstream
Multi-year Patterns
Milder winters along US-Canada borderIncreased winter storms in CaliforniaFloods in SE, snow in SW mountainsDecreased hurricane activity in Atlantic
El Nino
Multi-year Patterns
More, stronger tornadoes in MidwestMore, stronger hurricanesDrought, forest fires in SW
La Nina
Plant Physiognomy
North-south gradient in vegetation form due to temperatureWest-east changes in response to precipitation
Plant Physiognomy
Tree line climate can produce strange tree forms - krummholzAtypical growth pattern resulting from borderline growth conditions - mean annual soil temps. <5-8°C, air temps. ~10°C
Plant Physiognomy
Gradual transition from west to east, grassland to woodland to forestChanges in amount, seasonality of rainfall
Plant Physiognomy
East of Rockies, start with short-grass prairieLow-growing clumps of grass with bare patches between clumps
Plant Physiognomy
Gradual shift from midgrass prairie to tallgrass prairie in Nebraska/IowaTaller grasses, forbs, more diversity and biomassFollows pattern of increasing rainfall
Plant Physiognomy
Further east - trees appear in places other than along streamsWoodlands - dominated by trees, but without a closed canopy (oak savanna)
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Plant Physiognomy
Seasonality of precipitation (spring and fall) and warmer temperatures increase chance of drought in grasslands
Plant Physiognomy
Mid-, tall-grass prairies experience fire every 3-5 years (too little combustible material in short-grass prairie)Trees can’t survive frequent fires (apical meristems)
Plant Physiognomy
Woodlands appear where fire frequency is low enough to allow trees to grow tall enough to avoid fireStill are more fire-tolerant species
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