Vegetation and carbon cycling in La Chaux d

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Vegetation and carbon cycling in La Chaux dAbel

• Source of data M.Sc. thesis Emanuela Samaritani
• Supervision Andy Siegenthaler, Edward Mitchell,
  Alexandre Buttler, Hans-Rudolph Pfeiffer (Univ.
  Lausanne)
• Special assistance Mika Yli-Petäys

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Time since onset of regeneration estimated from
dendrochronology

• Median ages
• A 27 years
• B 31 years
• C 44 years

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Vegetation
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Regeneration Sphagnum increases, graminoids
decrease

• Sphagnum cover
• Median Average
• A 71 72
• B 89 90
• C 91 78

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Vegetation Point quadrat estimates - Similarities
Among A, B, C between pairs of sites
Among vs. within
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Vegetation PCA of point-quadrat data
More Sphagnum
More graminoids
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Gross photosynthesis -seasonal trend

• A C lt B

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Net primary production of Sphagnum
Sphagnum (NPP)

• N.b. NPP values much too low, gt need to redo
  calculations!
• Aver. length growth estimated NPP A 5.9
  cm gt approx 600 g.m -2.yr -1B 3.2 cm gt 300
  g.m -2.yr -1 C 2.9 cm gt 300 g.m -2.yr -1

NPP (g/m2)
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Total dark respiration, seasonal trend
A
B
C

• Dark respiration A gt B gt C

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Net ecosystem exchange - seasonal trend

• Highest in stage B

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CH4 emissions - seasonal trend

• Highest in stage C

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CH4 emissions, averages

• A lt B lt C
• Median (mg CH4-C.m-2.h-1)
• A 0.27
• B 0.49
• C 1.42

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Summary
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Peat temperature
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Water table depth
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Leaf area index
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Model parameters
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Photosynthesis vs PAR