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Lianas in a CO2-rich world

Project leader, researchers and collaborators: 
PhD Candidate Geertje van der Heiden, Assoc Prof Doreen Boyd, University of Nottingham, Assoc Prof Rachael Gallagher, Prof Matthias Boer, Dist Prof Belinda Medlyn

Funding period: 

Project summary: The aims of this collaborative research proposal are to study lianas in an elevated CO2 enrichment experiment in Australia to:

  1. Identify the relationship between CO2 enrichment and liana leaf productivity relative to trees,
  2. Identify the mechanisms, in terms of different leaf traits, which impact on the responsiveness of lianas and trees to CO2 enrichment,
  • Develop a model of forest carbon dynamics that integrates the impact of lianas under enriched CO2.

This novel collaboration will give access to a Free Air CO2 Enrichment (FACE) experiment in Australia. Without evidence from a FACE experiment containing adult lianas, there can be no credible mechanistic exploration of how lianas may be affecting forest dynamics in the future. For instance, the current lack of knowledge about liana impacts on trees under high CO2 precludes their inclusion in ecosystem simulation models. Such ecosystem models allow us to model liana increases and their effects on the forest carbon cycle to the global scale. This work will therefore contribute vital understanding to be able to accurately incorporate liana impacts in vegetation models, ultimately leading to the first incorporation of lianas in global climate models.

Update 3/5/2022

Dr Will Woodgate (ARC DECRA Fellow, UQ) proposes to collect 15-20 leaves attached to small twigs to sample combined SIF, reflectance, transmittance, and photosynthesis parameters using a customised LI-6800 with two spectrometer attachments. Half of the 20 samples will be lianas (n=10), split into ambient CO2 (outside the rings, n=5) and elevated CO2 (n=5). The other half of the samples will be eucalypt species (n=10), again with 5 samples for ambient (outside the ring) and 5 samples for elevated CO2. The twigs will be placed immediately into water to preserve the gas exchange properties of the leaves.

Another 40 leaves are planned to be collected in the same stratification (without twigs) purely for spectral characterisation and SIF. The sample numbers are summarised in the table below:

References:

 

 

Elevated CO2 (n)

Ambient CO2 (outside ring, n)

Leaves with twigs

  

Eucalypt

5

5

Lianas

5

5

Leaves without twigs*

  

Eucalypt

10

10

Lianas

10

10

*no gas exchange