Leaf and Floral Allometrics in Relation to Hydraulic Conductivity in Chaparral and Coastal Sage Shru

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Leaf and Floral Allometrics in Relation to
Hydraulic Conductivity in Chaparral and Coastal
Sage Shrubs

• Louis Santiago1, Susan Lambrecht2,
• Tim Jones3, Caroline DeVan1, Sarah Pasquini1,
• Lee Buckingham1, J. Carlos Cervera1
• 1UC Riverside, Botany Plant Sciences
• 2San Jose State, Biological Sciences
• 3Agricultural Research Service, Reno, NV

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Axes of ecological strategy variation

• Leaf economics spectrum (investments of C and
  nutrients in leaves rate and duration of returns
  from investments)
• Height (max height, pace of height growth, wood
  density)
• Reproductive allocation (seed mass vs seed
  output)
• Roots (max depth, architecture properties of
  fine roots)
• Allometrics (Corners rules canopy
  architecture)
• Hydraulics (water transport vs resistance to
  embolism)

Westoby et al. (2002) Ann Rev Ecol Sys, Westoby
Wright (2006) TREE
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Questions about axes

• Do certain trait combinations produce beneficial
  strategies?
• What are the costs and benefits of specializing
  in one end of a trait axis?
• Are certain traits related to growth forms,
  phylogeny, or resource availability?
• How do ecological strategies relate to where
  species grow best ?

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Integrating across scales

• How does the distribution of ecological
  strategies at a given site affect ecosystem
  processes?
• Can ecological strategies and positions along
  functional axes predict how species respond to
  environmental disturbance or change?

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Photosynthesis scales with hydraulic conductivity
in rainforest trees
Santiago, Meinzer, Goldstein et al. (2004)
Oecologia
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Photosynthesis also scales with wood density
Santiago, Meinzer, Goldstein et al. (2004)
Oecologia
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Relating Allometrics and Hydraulics in Shrubs

• How does leaf area scale with stem diameter?
• As evaporative units, how are floral structures
  related to stem allometrics and hydraulic supply?

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Leaf area vs. sapwood area
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Leaf area vs. sapwood area
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LSC vs. Sapwood area
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Leaf-Stem Allometrics

• Greater diameter stems support proportionally
  greater leaf area
• Implications for gas exchange
• Constrained in high leaf area species?
• Greater leaf area offers more self-shading
• Micro-environment

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Floral Traits

• Flower size (cm2)
• Total floral area (cm2)
• Specific petal area (SPA cm2 g-1)
• Hydraulic conductivity per unit floral area
  Kpetal (kg m-1 s-1 MPa-1)

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Floral area vs. leaf area
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SPA vs. wood density
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FA/SA vs. wood density
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Native Kpetal values
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Leaf area vs. wood density
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Sapwood area vs. wood density
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Summary Slide

• Floral evaporative area increases with leaf area
• Seasonal studies are needed to dynamic
  evaporative area
• More information on potential transpiration of
  petals needed
• Wood density is statistically related to many
  axes of variation

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Susan Lambrecht San Jose State
Tim Jones ARS Reno, NV
Caroline DeVan UCR