Taxonomy and autecology of the grey box (Eucalyptus moluccana roxb. s. lat.) - Myrtaceae
Date
1976
Authors
Gillison, Andrew Napier
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Abstract
Grey box forms part of a woodland complex that is
restricted to the eastern part of Australia from 170 to 35°
S. Lat. and occurs within a range of about 1 x 106 km2. It is
not an important timber species although it has some significant
uses. It is of indirect importance as it is related to lands of
high agronomic value in New South Wales and is also a significant
component of woodlands in Queensland.
Apart from the geographic extent of the complex it is
also comprised of a number of closely related taxa that have
provided considerable taxonomic problems in the past due to their
clinal nature. Before any ecological investigation could be
commenced it was therefore vital to make certain that the species
under consideration were genecotypically distinct so that management
predictions could be applied with some certainty. This required
a comprehensive taxonomic revision coupled with a controlled
environment study to test genotype identity. For the first part,
numerical techniques were used to handle the large number of closely
related morphological attributes.
Pattern analysis programs available on the CSIRO CYBER 76
involving classification and ordination procedures provided a background
of taxonomic pattern within grey box that was used to assist
the subjectively based revision. The advantage of such a method
allowed some unexpected insight into morphological relationships
that were clearly related to environmental variables.
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The revision produced three new subspecies of E. moluccana,
namely subsp. pedicellata, subsp. queenslandica and subsp. crassifolia,
all of which follow a geoclimatic continuum. Classifications and the accompanying ordination of growth, morphological and chemical
data from seedlings of grey box grown under a range of temperature
maxima (150, 21°, 270, 33° and 36°C) were compared with those of
the parents. A high correlation was obtained, indicating that at
an infraspecific level there is support for the hypothesis of nonspecificity.
A method of comparing ordinated centroids from the
classifications is put forward.
The structure of the thesis is arranged so that the
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comparison of the seedling and parent characters via ordinationwere included
as part of the revision, i.e. it precedes the phytotron investigation.
This facilitated the use of the revised names in the growth studies
in a way that would not otherwise have been possible. Having
completed the revision and established that the genecotypes were
classifiable by phenotypic characters it was then possible to
proceed with the establishment of a range of representative field
sites.
The environmental study took into account community
structure at a fine level and because of the largely ubiquitous
floristic components included a minimal amount of floristic data.
The ensuing classification revealed a distinct tropical versus
temperate division that isolated grey box communities immediately
north of the Queensland border and also north of the Tropic. An
analysis of soil variables between contiguous communities showed
no meaningful pattern. However climatic variables were highly
correlated with the distribution of seedlings of the revised taxa.
The continuing use of the same broad numerical techniques facilitated
a quantitative comparison between data sets in almost every case.
The additional use of canonical variate analysis and canonical
correlation analysis also enabled a clearer insight into group
structure of the different classifications and in addition to diagnostic computer programs assisted in reducing the numbers
of attributes required to recover an accepted classification.
As a follow-on to the environmental study a competition
experiment between E. moluccana and E. crebra carried out in a
controlled environment allowed some further inferences to be
made about the field situation where E. crebra occupies poorer
sites to the exclusion of grey box.
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Thesis (PhD)