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Population genetics of the rare Tasmanian endemic, Eucalyptus cordata

Brad Potts
University of Tasmania
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Peter Harrison samples the western form of E. cordata (ssp. quandrangulosa) from Snug Plains, Tasmania.


Peter Harrison, a UTAS honours students is well advanced on his study of genetic variation in the rare Tasmanian endemic Eucalyptus cordata.  This eucalypt species is distributed as a series of small, disjunct populations in south-eastern Tasmania and is closely related to other endemic alpine white gums (E. morrisbyi, E. gunnii, E. archeri and E. urnigera).  An eastern (ssp. cordata) and a western (ssp. quadrangulosa) subspecies of E. cordata were described recently (Nicolle et al. 2008; see related article in Biobuzz 7).  The western subspecies tends to occupy cooler and wetter sites than the eastern subspecies and is distinguished from it by several morphological traits including the quadrangular, as opposed to rounded, branchlets.  

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The shrub-like eastern form of E. cordata (ssp. cordata; bluish plants in the foreground) can be seen here growing beneath E. pulchella and E. viminalis on a dry north-facing hill slope in the Bluestone Tiers, Tasmania.


Peter's project is looking at the population genetics of Eucalyptus cordata and will extend the molecular studies of the endemic alpine white gums undertaken by Alex Mathews (2010 - see article in Biobuzz 13) and Corey Hudson (2007).  He will be using nuclear microsatellites and chloroplast DNA sequence data to determine the levels of genetic diversity within and between populations of E. cordata, whether the western subspecies is the derived form and how the E. cordata populations relate to the broader alpine white gum complex.  In the later case, there are several populations currently assigned to E. cordata which are atypical and may have affinities to other alpine white gum taxa.

Peter plans to sample 25 individuals from 20 populations from throughout the geographic range of E. cordata and is currently over three-quarters of the way through the field sampling.  

Reference

Hudson C (2007) Genetic studies of the Eucalyptus gunnii–archeri complex and related species on the Central Plateau. Honours thesis, University of Tasmania.



Biobuzz issue fifteen, December 2011