AbstractIn this study, I aim to provide basic biological and ecological knowledge about Bambusa amhemca, the sole bamboo occurring wild in the Northern Territory of Australia, as a prelude to management considerations.
On the basis of a detailed morphological description, the generic placement, monospecific status, and endemicity of B. arnhemica are confirmed. At global and catchment scales, a seemingly idiosyncratic distribution may be explained as the product of infrequent and incomplete dispersal across and away from riparian areas, combined with passive dispersal downstream. At local scales, evidence is provided that B. arnhemica is constrained by poor drainage during the dry season, and by the high frequency of fire in the savanna matrix within which it is embedded. However, seedlings cope remarkably well with both fire and prolonged wet-season inundation. Bambusa arnhemica is gregariously semelparous, flowering in patches ranging from 0.002 to 3200 km2. A temporally-ordered but spatially-chaotic flowering wave commenced in 1996, affected c. 80% of stands by 2002, and is ongoing. It is proposed that gregarious flowering is initiated by an endogenous clock that usually overrides environmental effects, and maintained by strong selection against asynchrony. Synchronicity is progressively fragmented over generations by occasional environmental effects that induce synchronously early or late flowering without altering the endogenous clock, but renewed with dispersal and speciation.
Bambusa arnhemica is facultatively deciduous. Rapid elongation of culms occurs during the mid- to late- wet season, and must be completed before the onset of the dry season, a trait that may limit B. arnhemica to sites where wet-season moisture is prolonged and reliable.
Bambusa arnhemica is neither a recent arrival nor an ancient inhabitant of northern Australia. Gregarious occupation of space and gregarious flowering by semelparous bamboos provides intriguing perspectives on the conundrum of group cf individual selection. Clumping bamboos are ideal subjects for intensive management and harvest, but pose unusual problems for harvest from wild stands.
|Date of Award||2004|
|Supervisor||David Bowman (Supervisor)|