The phenology of the plant community Alison Specht

1. Dec. 1994 Mar 2002
The phenology of the plant
community – more properly, a
story of exploration
Alison Specht

2. What controls vegetative growth?
Hypothesis 1
• Light-mediated hormone triggers
• Temperature-mediated hormone
triggers
• Whatever…
• Affects survival, distribution and
community composition and
structure

3. Investigation 1
• Is it temperature?
– In-situ adult individual monitoring of canopy
dynamics
• tagging and
• litter collection
– Controlled environment studies
– Other things….

4. Shoot tagging (three
adults 35m)
Corymbia intermedia

5. Shoot tagging (three
adults circa 32m)

6. Litter – Moggill State Forest

7. Litter – Moggill State Forest

8. 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

11. Putting together

12. Putting together

13. 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

14. 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?

15. rainforest

16. rainforest

17. rainforest

18. rainforest

19. rainforest

20. rainforest

21. But this is wandering into productivity and
broad questions of biodiversity

22. the community – temporal
partitioning of resource
demand through phenology

23. the community – temporal
partitioning of resource
demand through phenology

24. the community – temporal
partitioning of resource
demand through phenology

25. the community

26. the community

27. the community

28. the community

29. the community
These three species co-occur
because their demand for
limited resources is staggered in
time.

30. 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

31. 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.

32. 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