POPULATION-GENETICS OF THE LONG-LIVED HUON PINE LAGAROSTROBOS-FRANKLINII - AN ENDEMIC TASMANIAN TEMPERATE RAIN-FOREST TREE

Genetic diversity, within and among natural populations at 32 sites, o f the long-lived temperate rainforest Huon pine tree Lagarostrobos fra nklinii was assessed using isozymes. Overall, genetic diversity, based on six enzyme loci, was low (A = 1.6, p = 46%), both within and among populations (Pst = 0.095). The most isolated sites (Yellow Creek, Spe ro River, Newall Creek, Mt Read) deviated significantly from expected allelic frequencies and/or had the greatest genetic distances from oth er sites. Most of these isolated sites are currently unprotected. Geno type frequencies within most sites (20 out of 32) deviated significant ly from Hardy-Weinberg equilibrium expectations (p < 0.0015) and had h igh fixation indexes indicative of effective inbreeding. The high leve ls of inbreeding observed by these measures at some sites did not refl ect isolation from gene flow. The most similar pairs of populations we re located in the headwaters of the three major habitat catchments, wh ich originate within close geographic proximity of one another. Over 9 0% of individuals at Mt Read, the highest altitude site known, were ge netically identical. This, combined with other evidence, suggests that the population at this site is principally vegetatively derived and m ay be exceptionally old. Inbreeding and low diversity does not appear to have affected the species' ability to persist for long periods. (C) 1997 Published by Elsevier Science Ltd.