XVI International Botanical Congess

In the mesic savannas of the Darwin region of northern Australia (rainfall 1600 mm p.a.), approximately half of the woody species are evergreen, and half are deciduous. The dominant trees are evergreen eucalypts that transpire year-round, flower (and hence provide nectar) and flush during the dry season. Most woody species flower once per year, with no super-annual carryover of seed in the canopy. Leaf flush, flowering and fruiting peak in the late dry season, when VPD is highest, and soil moisture lowest. There is inter-specific and inter-annual variation in the timing of flowering and leaf flush. Triggers to leafing and flowering are complex, involving interactions between whole plant water status, and climatic factors such as changes in soil moisture and humidity. Fires in the late dry season are a potential threat to the floral and fruit reserves within these savannas.