Climate Change Exercise

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Climate Change Exercise

• Median 84
• See answer key http//www.montana.edu/phiguera/G
  EOG302/Assignment_II_key.pdf

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Climate Change Exercise
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Climate Change Exercise
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Climate Change Exercise
5
Climate Change Exercise
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Climate Change Exercise
5. Predictions for tree species at Grizzly Bear
Forest, assuming all winter precip falls as
snow   21st Century SAR averages Commit .6 -
.8 Between 39cm and 52cm B1 1 decreasing
to .6 65 to 39cm A2 .75 decreasing to .35
49 to 23cm     Probable Consequences if SAR
averages prove accurate Commit Scenario As
mean winter precipitation shifts into the 40s
mountain hemlock probability of occurrence drops
to .15 to .30. Consequently, whitebark and
lodgepole pine occurrence probability rises to
near 1. B1 Scenario Similar transition as Commit
scenario from mountain hemlock occurrence of
.8-.6 to .4 -.2. Corresponding rise in whitebark
and logdepole probability to .8 - .95. A2
Scenario As winter moisture falls to levels near
23cm whitebark pine probability falls to .8 and
lodgepole drops slightly from peak probability
but increases in proportion. 
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Climate Change Exercise

• 8. Potential limitations
• The Grizzly Bear forest is a small portion of the
  area analyzed by the CCSM3 models. Due to the
  relatively small area of the Grizzly Bear forest
  and the spatial resolution (1.4 degrees) of the
  models, some local variability present in the
  area may not have been accounted for, making
  detailed inferences inadvisable.
• The time period analyzed by the CCSM3 models
  could be a fraction of the lifespan of some
  individual trees.  Because many conifers tend to
  have lifespans greater than 100 years, the
  effects of the predicted snowfall amounts may not
  be readily observable until decades or centuries
  after the end of the model predictions (although
  the results may be still be similar).
• The figure from McKenzie et al.  does not specify
  the impacts of abiotic and biotic limiting
  factors on the arboreal populations. Since the
  figure does not indicate if the degree to which
  the relative proportions of lodgepole pine,
  whitebark pine, and mountain hemlock are affected
  by biotic and abiotic factors, it is difficult to
  know if the ranges occupied are functions of just
  precipitation or precipitation and competitive
  exclusion.
• 4. The amount of precipitation that falls as
  snow is not specified by McKenzie et. al. This
  limitation was discussed in 5, but it still
  bears mentioning that the percentage of
  precipitation that falls as snow currently is
  unknown. Similarly, the models do not account
  for mid-season melts which could impact the
  functionality of winter snow as a reservoir.
•  

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Climate Change Exercise

• Common names of trees are not capitalized, unless
• it is named after a person e.g. Douglas-fir,
  Engelmann spruce

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Speciation and Extinction2 March, 2009

• Systematics
• Macroevolution
• Speciation
• Extinction
• Species selection

http//en.wikipedia.org/wiki/Darwin's_finches
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3. Speciation

• Diversification
• character displacement divergence of a feature
  of two similar species where their ranges
  overlap reduces competition

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Textbook Fig. 7.3
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3. Speciation

• Adaptive radiation
• diversification of species into a wide range of
  ecological niches numerous decedents from a
  single ancestor
• Example
• Hawaiian
• honeycreepers
• Galapagos
• finches

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Textbook Fig. 7.21 see also Fig. 7.14
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Speciation and Extinction2 March, 2009

• Systematics
• Macroevolution
• Speciation
• Extinction
• Species selection

http//en.wikipedia.org/wiki/Darwin's_finches
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4. Extinction

• Extinction as an ecological process
• Starts at the population level
• Probability-of-extinction increases non-linearly
  as population size decreases

Death rate ½ birth rate
time to extinction (years)
Death rate birth rate
Death rate 2 x birth rate
Birth rate 1.0 (for all lines)
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Population size ()
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4. Extinction

• Recent extinctions
• Passenger Pigeon (Ectopistes migratorius)
• Original population in the
• millions, perhaps billions
• Hunting (1870s), 2000-3000/day
• 1914 last bird (Martha) died in
• Cincinnati zoo
• American chestnut (Castanea dentata)
• One of the most abundant tree in eastern
  deciduous forests
• Chestnut blight fungal pathogen introduced from
  Asia (NYC, 1904)
• Likely lt100 mature
• trees remaining

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5. Species selection

• Species selection
• Analogous to natural selection, but at the
  species level species with certain
  characteristics increase while other decrease of
  become extinct.

Dispersal Mode
Duration in fossil record
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5. Species selection

• Examples differential survival and proliferation
  of placental mammals after the K-T mass
  extinction.

Placental mammals (infraclass Eutheria)