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How will rapid climate change affect
species and ecological communities?
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Species phenology and growth
Phenotypic expression of species
Species’ population dynamics
Gene frequencies in populations (evolution)
Species distributions
Species interactions
Disturbance processes and community dynamics
Ecosystem structure and dynamics
Biomes: global patterns of plant
response to climate
• Biomes are general ecosystem
types that occur under a
particular climate regime, and
exhibits characteristic
vegetation structure,
community organization, and
ecosystem processes.
Cold needle-leaved woodland
(lodgepole pine) and cold shrub steppe
(Great Basin sagebrush), Yellowstone
National Park, 24 years after fire
Montane tropical broadleaved evergreen forest
Boreal needle-leaved evergreen forsst
Temperate deciduous
broadleaf forest
Humid tropical broadleaved evergeeen forest
The Mediterranean Biome
CA
SW Australia
Crete
Climate and Terrestrial Biomes, circa 1960
R. Whittaker
Biomes, circa 2000:Coupled vegetation-climate
interactions at the global scale
Bonan et al. Global Change Biology 2003
Temperature and biological
patterns
• Species and
community range
limits
• local distribution
patterns
• population age
structure
• genetic differentiation
• ecosystem processes
Physical Constraints on
organisms
• Microclimate
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Radiation
Temperature
Energy
Water & humidity
• Nutrients
• Toxins
• Mechanical stress
Dresig. 1980. Oecologia.
Climate and Habitat
• Habitat is “the
resources and
conditions present in
an area that produce
occupancy” (Hall et al. 1997.
Wildlife Soc. Bull. 25: 173-182)
• Climate space –
radiation, wind,
temperature, humidity
• Microclimate
Post et al. Science, September 2009
Nemani RR, White MA, Cayan DR, Jones GV, Running SW, Coughlan JC,
Peterson DL
Asymmetric warming over coastal California and its impact on the premium
wine industry. Climate Research Nov 01.
http://ndis.nrel.colostate.edu/herpatlas/coherpatlas/im
ages/Species/Turtles/paintedhead.jpg
Janzen, F.J. Proc. Nat. Acad. Sci. 1994.
Heat balance of an animal
Energy balance of an organism
M + Qa = R + C + E + G + X
M
Qa
R
C
E
G
X
Metabolic energy
absorbed radiation
emitted radiation
energy exchanged by convection
latent heat energy
energy exchanged by conduction
net energy loss or gain
Some considerations in
bioclimatology of animal species
• Endotherms vs. ectotherms
– 99.9% of species are ectotherms that rely primarily on
external sources for body heat
• Behavior
– Diurnal vs. nocturnal
– Fossorial, semi-fossorial vs. non-fossorial
– Hibernation, torpor
• Nutritional status
• Age and stage of development
Climate space (“Fundamental niche”)
modeling
• Organism
– Body mass
– Voluntary min and
max T
– Selected body T
– Latent heat transfer
rate
– Resting metabolic rate
– Degree days for egg
development
• Environment
– Solar radiation
– Wind profile
– Air Temperature
profile
– Relative humidity
– Soil temperature
profile
Scales of environmental
temperature variation
• Global
• Regional
– Land/water
– Elevation
• Local
– Slope angle and aspect
• Microsite
– Vegetation canopy, soil
moisture, etc.
Bay checkerspot butterfly
Murphy and Weiss (1992) Chapter 26 in Global Warming and biological diversity,
ed. R. L. Peters and T. E. Lovejoy. Castleton, New York: Hamilton
Printing.
Climate change and plant species
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Temperature
Soil water balance
Carbon dioxide
Dispersal and adaptation
Wollemia nobilis
Climate and Photosynthesis
• Photosynthesis
6 CO2+ 6 H2O ----sunlight----> C6H12O6 + 6 O2
• Rate controlling factors
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Radiation
Temperature
Water
Carbon dioxide
Nutrients (nitrogen)
Photosynthesis and plant water
balance
Absorption depends on:
soil water
soil water osmotic potential
root osmotic potential
soil temperature, oxygen
Transpiration depends on:
leaf water, temp.
air temp, humidity
leaf shape, resistance
H2O
Scurf-pea
http://www.fhsu.edu/biology/thomasson/stomate.htm
Equisetum
CO2 response curve of photosynthesis
• Diffusion limitation affected by stomata
• Biochemical limitation affected by light/enzymes
• Plants equalize physical and biochemical
limitations
Inherent tradeoff between CO2 gain and H2O loss
Influence of different parameters on the efficiency of the carbon
dioxide uptake (ordinate) of a C3 plant (Atriplex patula, yellow line)
and a C4 plant (Atriplex rosea, green line). Measured parameters
(from left to right): light intensity, leaf temperature and concentration
of carbon dioxide within the intercellular space (according to O.
BJÖRKMAN and J. BERRY, 1973).
Water use efficiency
• C3 plants
1-3 g CO2 intake / kg H20 loss
20-35°C optimal temperature
• C4 Plants 10-40 g/kg
30-45 C
• CAM Plants 20-40+ g/kg
20-35 C
GPP, NPP, and NEP
• Photosynthesis usually measured in units of moles
carbon/leaf area/time (usually reported as net
photosynthesis)
• Gross Primary Production (GPP) is a measure of
photosynthetic activity
– carbon uptake per ground area per time
– Around 50% of GPP is used in respiration
• Net primary production (NPP) = GPP – Respiration
– Net carbon (or biomass) per ground area per time
• Net ecosystem production (NEP) measures change in total
organic matter per area per time
– NEP = GPP – Respiration of Autotrophs and Heterotrophs
Components of NPP
Components of NPP
% of NPP
New plant biomass
40-70
Leaves and reproductive parts (fine litterfall)
Apical stem growth
Secondary stem growth
New roots
Root secretions
20-40
Root exudates
Root transfers to mycorrhizae
Losses to herbivores, mortality, and fire
1-40
Volatile emissions
0-5
10-30
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0-30
30-40
10-30
10-30
What do we usually measure??
Litterfall
Sometimes stem growth
Source http://www.faculty.uaf.edu/fffsc/PPTChap6.ppt.
Patterns of NPP vary strongly with climate
Possible responses of plants to
increased atmospheric CO2
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Decreased stomatal conductance
Decreased transpiration
Increased water use efficiency
Increased photosynthetic rate
Decreased nitrogen concentration
Increased phenolic concentration
Long term Acclimation
Predicting plant species
responses to rapid climate change
• Plants can
– Tolerate
– Adapt
– Disperse
• Issues
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Local phenotypic and genotypic variation?
Rate of adaptation vs. rate of climate change?
Dispersal rates in fragmented landscapes?
Photoperiod vs. climate controls on phenology
Predicting future plant species
distributions
• Lessons from the past
• Approaches
– Bioclimatic modeling (realized niche models)
– Physiological models (fundamental niche
models)
– Spatial population and community models
– Dynamic [global or regional] vegetation models
• Dispersal through fragmented habitats
Neotoma sp. (packrat)
Packrat midden,
Grand Canyon, 13000
yrs. BP
Alder pollen
Present potential veg
Vegetation 15,000 YBP
Measured rates of spread for tree
genera during postglacial period
• Oak
• Spruce
• Hemlock
7 km/generation
0.3-1(8) km/generation
0.5-3 km/generation
• Dispersal in fragmented habitats?
Summary points
• Microclimate is the climate experienced by
organisms
• Species occupy distinctive habitats that reflect
their physiology, interactions with other species,
and dispersal. Species respond individualistically
to climate variation
• Species persistence under a changing climate can
occur through tolerance, adaptation or dispersal
A few summary points (2)
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Oceans and humid forests account for roughly
2/3 of the earth’s net primary production.
Gross and net primary production increase in
warmer and wetter climates
Plants interact with the atsmophere to modify
local, regional and even global climate.
Increased CO2 increases water use efficiency of
plants, especially C3 plants