Reedia spathacea F.Muell.: a study of the phylogeography, population structure and co-occurrence of a critically endangered sedge
My project aims to answer the question: Is Reedia spathacea a relictual taxon?
Reedia spathacea F.Muell is a declared rare, critically endangered species of sedge (Cyperaceae) found in the peat swamps of the Jarrah Forest and Warren Biogeographical Regions (Dept. of Environment, 2016). Reedia has been identified as a Gondwanan relict on the basis of morphological evidence (Tauss, 2000). Characteristics of relictual taxa in the south-west include being of Gondwanan or Pangaean origin (Wardell-Johnson & Horwitz, 1996), thus having become restricted to mesic habitat from a previously wider distribution (Hearn et al, 2002; Rix et al, 2015) and retaining some ancestral morphological states (see Burnham, 2014). They also are expected to have high interpopulational genetic diversity with relatively low intrapopulational diversity (Burnham, 2014) and be phylogenetically distinct from sister taxa (Nistelberger et al, 2014). These criteria will be used to explore whether R. spathacea is a relictual taxon using chloroplast and microsatellite DNA analyses supported by morphological and phylogeographic evidence. If this study supports the recognition of R. spathacea as a highly-restricted relict then the genetic consequences of historical population decline or future extinctions can be addressed. In a broader sense, our understanding of organisms that have become rare will be improved, in turn bettering our understanding of the pressures that have caused contraction in ranges historically, helping us to predict future trends in the face of a rapidly changing climate.
Dr Margaret Byrne, DPaW
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