A disjunct population of Eucalyptus globulus ssp. bicostata from South Australia.

A population of Eucalyptus globulus ssp. bicostata was recently discovered at Mt Bryan (SA) which is more than 600 km from the nearest other population of this taxon. The aim of this study was to determine whether this population is natural or whether it might have been planted after the arrival of pastoralists to the area. To achieve this aim we used RAPD molecular marker analysis of a large (10 m diam) lignotuberous stand of E. globulus ssp. bicostata that roughly formed a ring. The RAPD analysis indicated no differences between samples taken from the lignotuberous stand, although individuals from outside it were all different from it and from one another. Because the lignotuberous stand of E. globulus ssp. bicostata is likely to originate from a single individual and is very large, it is likely to be very old (possibly as old as 4000 years) and this would imply that the population was not established by pastoralist. How did the E. globulus ssp. bicostata become established on Mt Bryan? Four possibilities are discussed, namely, natural long distance seed dispersal, seed dispersal by humans before the arrival of pastoralist, long distance pollen dispersal and connection to the Victorian Eucalyptus globulus ssp. bicostata forest in the past.