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Ecological Biogeography
examines the factors
(principally physical) that
control the range and abundance
of organisms
ENVIRONMENT
(climate, soil, . . .)
BIOTA
Species-environment
relations
Individual performance
(e.g. growth or reproductive success)
Biogeographic consequences
Extreme conditions may control a
species distribution
 Low temperatures (polar areas)
 High temperatures (deserts)
today
 Dessication (deserts)
 Saturated soils (bogs)
 High salinity (ephemeral lakes)
 Low nitrogen (dune-fields)
next week
The rotation
of the Earth
produces a
24h daynight cycle
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Image: earthobservatory.nasa.gov
Diurnal temperature variation in a nonvegetated (desert) environment
Effects of
vegetation
on diurnal
rhythms:
thermal
regimes in
a tropical
rain forest
Seasonal
variations
in day and
night
length are a
product of
axial tilt
Day and night length varies
with latitude
Graphic: M.
Pidwirny
Biogeographic implications of
variations in daylength: photoperiodism
red clover
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
vegetative
“Japanese”
anemone
night
night
vegetative
day
day
QuickTime™ and a
TIFF (Uncomp resse d) d eco mpres sor
are nee ded to s ee this picture .
Long-day plants: flower after exposure to long days/short nights (spring);
predominant in cool temperate and polar latitudes
Short-day plants: flower after exposure to short days/long nights (fall);
predominant in warm temperate and subtropical latitudes
Seasonal solar radiation receipt
varies with latitude
(as a result of variations in daylength and solar angle)
Graphic: M.
Variable radiation
receipt produces
seasonal variations
in surface
temperature
above: Manaus, Brazil (3°S)
below: Fairbanks, Alaska (65°N)
Graphics: M.
Extremophiles
• Archaeans (bacteria) can
survive and grow over an
extreme temperature range,
from >113°C in oceanic thermal
vents to -18°C* in bubbles of
brine in Arctic sea ice.
*the bacterium Colwellia, which grows in
microbial mats in Arctic sea ice, can
metabolize in liquid nitrogen (at -196°C)!
Source (and graphic): New Scientist, August 12, 2006
Temperature ranges of some common “coldblooded” organisms (poikilotherms)
Thermally limited growth/activity
season (e.g. Fairbanks, Alaska)
Surviving
extreme
temperatures
[migration,
hibernation,
dormancy (eggs,
seeds, pupae,
etc.)]
Temperature and habitat occupation
Water temperatures and
fish distribution
dormant
desert pupfish
dormant
?
goldfish
bald rock cod (Antarctica)
coho (adults)
0
10
20
30
Water temperature (°C)
40
© Joan Barnett
pupfish in
a hot
spring
stream,
Death
Valley
pupfish in Salt Creek, Death Valley
A eurythermal/haline animal:
the desert pupfish
(Cyprinodon spp.)
Photosynthesis-temperature relations
for major plant groups
Cardinal temperature
Thermal limits for trees from tropical,
temperate and boreal biomes
compare tropical, temperate and boreal species
Extreme temperature resistance in plants
Cold resistance
chilling
resistance
frost avoidance
by
supercooling
Heat resistance
frost
resistance
frost tolerance
heat tolerance
heat avoidance
by
shielding & reflection
thermal insulation
cooling by transpiration
Cold-resistance strategies
• Evolved responses
growth of fur & feathers, shorter/smaller extremities,
larger body size
• Seasonal responses
fat storage, metabolic changes (e.g. glycoproteins supress ice
formation in plants), deciduousness (loss of sensitive parts),
migration, hibernation
• Daily behavioural responses
habitat choice, refuging (nest, roost, burrow, den….), body
position and orientation (especially for poikilotherms)
Tropical species
e.g. effects of frost on Saguaro cacti in central Arizona
injured
dead
1961
1962
(after frost)
many dead
or dying
1979
(frosts: 1971, 1978)
Thermal
control on
polar limit
of saguaro
(Carnegiea
gigantea)
Saguaro
(Carnegiea
gigantea)
range in
relation to
frost
frequency
Polar limits of other tropical
desert species
Temperate forest trees:
common polar limits =
similar limiting temperatures?
American beech
red oak
red maple
(plus white oak, black oak, 2 hickories . . . . )
Is polar limit controlled by the length
and warmth of the growing season?
mean daily
temperatures
>10°C for more
than 4 months
mean July
temperature
18°C
Is polar limit controlled by
dormant season temperatures?
mean January
temperature
-12°C
Ice formation in beech (and red oak,
red maple, etc.) tree trunks
extracellular
-10
-20
Intracellular;
Cells ruptured
(°C)
-30
-40
Intra-cellular
Extra-cellular
Exothermic
reactions
(ice-formation
events) in
temperate and
boreal tree
species
Tree anatomy and thermal limits
Ring porous
chestnut
American elm
Diffuse porous
birch
red maple
Probability of temperatures falling below -40°C
A = common
B = rare
C = never
American beech
Hardiness zones:
annual temperature minima
zone 1
(-50°C)
to
zone 11
(0°C)
http://www.glfc.cfs.nrcan.gc.ca/frontline/bulletins/bulletin_no.13_e.html
0b
Shining willow
Saule brillant
Salix lucida ssp. lucida
1
1
1b
White spruce
Lodgepole pine
Laurel willow
Épinette blanche
Pin tordu latifolié
Saule laurier
Picea glauca
Pinus contorta var. latifolia
Salix pentandra
2
2a
2b
White elm
Cranberry viburnum
Ponderosa pine
Orme d'Amérique
Viorne trilobie
Pin ponderosa
Ulmus americana
Viburnum trilobum
Pinus ponderosa
3
3
3b
Rocky Mountain juniper
Red maple
White ash
Genévrier des Rocheuses
Érable rouge
Frêne blanc
Juniperus scopulorum
Acer rubrum
Fraxinus americana
4
4a
4b
Black locust
Rocky Mountain Douglas-fir
Scotch elm
Robinier faux-acacia
Douglas bleu
Orme de montagne
Robinia pseudoacacia
Pseudotsuga menziesii var. glauca
Ulmus glabra
5
5
5a
5b
Norway maple
English oak
Douglas maple
Horsechestnut
Érable de Norvége
Chêne pédonculé
Érable nain
Marronnier d'Inde
Acer platanoides
Quercus robur
Acer glabrum var. douglasii
Aesculus hippocastanum
6
6b
Western redcedar
Eastern flowering dogwood
Thuya giant
Bois bouton
Thuja plicata
Cornus florida
7
7b
Sweetgum
Coastal Douglas-fir
Copalme d'Amérique
Douglas vert
Liquidambar styraciflua
Pseudotsuga menziesii var. menziesii
8
8
Arbutus
Western flowering dogwood
Arbousier d'Amérique
Cornouiller du Pacifique
Arbutus menziesii
Cornus nuttallii
http://sis.agr.gc.ca/cansis/nsdb/climate/hardiness/trees2000.html
ZONE HARDINESS OF SOME INDICATOR TREES
When is cold good for a
plant?
• Short days signal plants of impending cold period
• Many deciduous plants require chilling to grow well
in subsequent growing season
• Vernalization required for buds to break out of
dormancy and to develop into flowers. These
plants (e.g. apple, lilac) cannot be grown
“successfully” at lower latitudes because the
winters never get cold enough (a few days at 0–
10°C).
• Hardening
Accclimation
to winter cold
initiated by
falling
temperatures
and reduced
photoperiod in
autumn
Temperature effects
cold hardiness vs. dormancy
• Cold hardiness is ability to withstand cold
• Dormancy is inability to achieve normal
growth
– Biological adaptation to region with decreasing
temperatures and shortened daylength
– Apples: require about 1000-1600 hours of
chilling (45F) to break dormancy.
http://www.uga.edu/fruit/apple.htm
Freezing resistance acclimation in two
willow (Salix) species in northern Japan
buds form
leaves
yellowing
leaves open
Freezing
resistance
in red-osier
dogwood
(Cornus
stolonifera)
ecotypes
growing in
Minnesota
Ecotypic
variation in cold
resistance in
Douglas-fir
(Pseudotsuga
menziesii)
Seeds planted May, 1954;
Seedling response to severe
frost (-16°C at ground level),
mid-November, 1955.
P. menziesii var. menziesii
N
S
N
var. glauca
S
100%
90%
80%
70%
60%
% undamaged
50%
% damaged
% killed
40%
30%
20%
10%
0%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Seedling
response to
severe frost
(-16°C at
ground level),
midNovember,
1955.
Freezing damage in tree
species ecotypes
What controls equatorward limits
of temperate and boreal species?
• Similar heat injury ranges
• Stratification: chilling requirements for seed
germination
• Vernalization: chilling requirements for
blossoming
In tropical areas the stratification and
vernalization requirements of temperate and
boreal plant species are not met; they are
unable to produce seed.