bio120 slides lecture02 2013

8/13/2019 BIO120 Slides Lecture02 2013

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General trends of terrestrial

vegetation with climatic variables Vegetation growth (primary productivity)

increases with moistureand temperature

Vegetation stature also increases! !so regions with certain combinations of

moisture and temperature develop

predictable, characteristic types ofvegetation = biomes (study Scitable module)

Seasonality is secondarily important2

Copyright 2013, James Thomson


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Biome types depend on combination of

temperature and precipitation

From Krebs after R.H. Whittaker

Highest productivity

Lowest productivity

My examples from:

Central America,

Vietnam

Ontario

Colorado

Arizona

Compare version in DB



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Latitude mostlydetermine major terrestrial

biomes; learn DB classification

Deserts near 30 deg N & S



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Additional climate patchiness

overlaid on basic latitudinal belts Temperature: land changes temperature more readily

than water; maritime climates are moderate, continental

climates are extreme; oceans provide thermal inertia

Precipitation: where does atmosphere get laden withmoisture; where does it condense? Evaporation high from warm bodies of water, low from cold Prevailing winds Orogenic precipitation: air forced up mountainsides undergoes

adiabatic cooling, precipitates on upper windward slopes

Rain shadows created on leeward slopes of mountain ranges Seasonality of moisture also important



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Earths tilt (23.5 !" produces

seasonality

Ricklefs Fig. 4.2

Ricklefs Fig. 4.3

Latitudinal patternscomplicated by

distribution of

landmasses



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Where are grapes and cherries grown

in cold climates? Maritime pockets

Door Co.,Wisc.

Niagara& Pelee,

Ontario

North Fork,Long Island



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The driest deserts occur inland of cold-water

upwellings: cold water => dry air

Compare Ricklefs Fig. 4.8Copyright 2013, James Thomson


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Montane rain shadows: Sierras and Rockies

Yellow = grassland (drier), east of RockiesCopyright 2013, James Thomson


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Biomes across elevational gradient:

Arizona mountains



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South-facing side of

Round Mountain, western Colorado

11Valley floor = irrigated hay pasture

Dry sagebrush scrub

Forest only at higher elevations & eastern flank



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North-facing side of

Round Mountain, western Colorado

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Forest across entire face



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Mt. Lemmon transect, AZ: Elevation correlated

with both temperature and precipitation; change of

100 m in elevation equals ~ 150 km of latitude

More info: http://www.saguaro-juniper.com/i_and_i/san_pedro/ecoregions/desert_to_skyisland.htm



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Mt. Lemmon transect: Sonoran desert, 712 m



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Mt. Lemmon transect: Oak grassland, 1338 m



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Mt. Lemmon transect: Pinyon pine-oak woodland,

1612 m



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Mt. Lemmon transect: Ponderosa pine, 1916 m



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Mt. Lemmon transect: Aspen, 2402 m



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Mt. Lemmon transect: Spruce-fir forest, 2750 m



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Mt. Lemmon transect: Spruce-fir forest, 2750 m



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Core ideas in physiological ecology

Ranges of tolerance(Lecture 1) ultimately limitdistribution

Organisms are complex chemical reactions Reactions occur (enzymes function) best at

optimum temperature and osmotic conditions,

where fitness is maximized

Many mechanisms for homeostasishaveevolved to challenge hostile environments

Maintenance of homeostasis requires energyand is often limited by constraints & tradeoffs



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Two types of range: ranges of

tolerance and geographical ranges Animalsgeographical ranges often correspond to

biomes, i.e.,limited by climate and/or vegetation!

!but sometimes not. Possibilities include: Limited to special habitats (behavioural habitat

selection)

Limited by other organisms (enemies, friends) Transcend biomes (ecological versatility, super

generalists) Not at limits because of recenthistory(e.g.,

limited dispersal)

Next slides: a sample of rangesCopyright 2013, James Thomson


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Limited by habitat: Pronghorn (Antilocapra americana):

broad climate tolerance, narrow habitat range (short-

grass prairie biome, American High Plains)

South Park, Colorado April 2012



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www.ownbyphotography.com

Yellow-rumped warbler

Dendroica coronata

Kirtlands warbler

Dendroica kirtlandii

www.birds.cornell.edu/

Idiosyncratic, species-specific habitat selection behaviour cangreatly influence distributions

Extreme

habitatgeneralist

Paradoxically

extremehabitat

specialist

(cognitive

limitation?)



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Transcending

biomes: broad

temperaturetolerance,

broad habitat

rangeTropicalrainforest,

Sumatra

Boreal forest, Siberia

Tiger,

Panthera tigris



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Range limited not by climate or habitat type but by

other animals: recent coyote expansion due to

humans, extirpation of wolves?

Coyote,Canis latrans



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Animals, size, heat budgets

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Rufous hummingbird Merriam shrewCopyright 2013, James Thomson

bio120 slides lecture02 2013

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