Aim of Project
The aim of this three year, multi-disciplinary, collaborative project is to understand and document the patterns of variation in the different types of Mulga and to provide a reliable means of identifying the taxa.
Specifically the aims are to:
- Develop an improved understanding of morphological variability within and among Mulga populations.
- Develop an improved understanding of genetic and developmental variability within and among Mulga populations.
- Create a taxonomic and evolutionary framework of the Mulga complex based on the morphological and molecular data.
- Produce scientific papers, interactive identification keys and a Mulga Manual field guide.
Understanding this variation and being able to identify the taxa are critically important because this provides the sound scientific foundation upon which management, utilisation and conservation rests. Such knowledge will enable Mulga species and communities to be better-protected from environmental perturbations, to be more effectively managed and sustainably utilized and will facilitate the identification of high priority areas for conservation together with other land uses. This in turn will lead to significant capacity-building within rangeland user communities that will have numerous benefits.
This study focuses on Western Australian Mulga populations. In this region the main centres of Mulga diversity are the Pilbara region, the northeastern goldfields region (roughly the Menzies-Wiluna-Meekatharra-Mt Magnet area) and the central ranges (around Warburton).
The different forms of Mulga in both monotypic and mixed stands will be examined and material sampled for taxonomic, genetic and complementary studies. The sampling strategy will encompass both the taxonomic and geographic variation within the group.
DNA will be extracted from specimens and microsatellite and chloroplast DNA variation data will be generated from both within and among populations. Mulga seedling DNA will also be extracted to test for the frequency of apomixes and root tip chromosome counts and flow cytometry methods will be generated in order to determine ploidy levels.
Morphological features of the phyllodes, pods, flowers, etc. will be measured and critically studied as a basis for describing the different Mulga entities (some of which will undoubtedly be new to science). The morphological data will be analysed using Principal Components Analyses and will be correlated with the genetic data. An electronic identification key for the Mulga entities will be constructed.
Ontogenetic information derived from seedling leaf development will similarly help in the identification and classification of Mulga taxa. Current evidence shows that neoteny occurs in at least some Mulga species (see Miller et al. 2002) and this phenomenon will be further explored by this study.
Anatomy. Anatomical investigation of pod and phyllodes venation patterns will complement the taxonomic investigation and will assist in the analysis of hybridization.
Embryology. There is indirect evidence of apomixes and polyploidy in Mulga. This study will develop protocols to document these events.
Further information on hybridization, apomixes, neoteny and polyploidy is provided on Joe Miller’s website.
Apomixes - asexual seed production
Taxa - any taxonomic category such as species, subspecies, variety, genus, etc.
Mixed stands - populations containing different taxonomic entities
Monotypic - populations containing only a single taxonomic entity
Neoteny - retention of juvenile features in adult growth phase
Polyploidy - multiple sets of chromosomes