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The phenology of the plant community Alison Specht
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Dec. 1994 Mar 2002
The phenology of the plant community – more properly, a
story of exploration
Alison Specht
What controls vegetative growth? Hypothesis 1
• Light-mediated hormone triggers
• Temperature-mediated hormone triggers
• Whatever…
• Affects survival, distribution and community composition and structure
Investigation 1
• Is it temperature?
– In-situ adult individual monitoring of canopy dynamics
• tagging and
• litter collection
– Controlled environment studies
– Other things….
Shoot tagging (three adults 35m)Corymbia intermedia
Shoot tagging (three adults circa 32m)
Litter – Moggill State Forest
Litter – Moggill State Forest
Phytotron
• Chose two species that co-occurred but had different distributions: E. maculata (now Corymbia variegata subsp citriodora) and E. drepanophylla (now bundled in with E. crebra)
• Two experiments – one in Plant Industry phytotron in Canberra, one in Brisbane
Putting together
Putting together
Hypothesis 2
• Vegetative growth is triggered by temperature, but mediated by availability of resources.
• Observational evidence. 1992 fire in southern Australia – killed around 100 people. Out-of-season shoot growth, dried due to drought -> paper thin, flammable shoots in canopy, tops and bottom fire
Availability of resources
• Second study – temperature x nutrients (phytotron & field studies) not available for today
• Third study – field observations and collation of temperature x water balance x nutrients?
rainforest
rainforest
rainforest
rainforest
rainforest
rainforest
But this is wandering into productivity and broad questions of biodiversity
the community – temporal partitioning of
resource demand through phenology
the community – temporal partitioning of
resource demand through phenology
the community – temporal partitioning of
resource demand through phenology
the community
the community
the community
the community
the community
These three species co-occur because their demand for limited resources is staggered in time.
So what is the point?
• The period in which a plant can produce new leaves and remain active is critical to its competitiveness and survival
So what is the point?
• The period in which a plant can produce new leaves and remain active is critical to its competitiveness and survival
• Temperature is a major trigger of meristematic production, followed by availability of resources. This appears increasingly to be a bit chicken and egg–mediated by sucrose, not hormones.
So what is the point?
• The period in which a plant can produce new leaves and remain active is critical to its competitiveness and survival
• Temperature is a major trigger of meristematic production, followed by availability of resources. This appears increasingly to be a bit chicken and egg–mediated by sucrose, not hormones.
• Temperature perception of the meristem is of key importance