The Conservation Genetics of Eucalyptus paliformis L. Johnson et Blaxell and E. parvifolia Cambage, Two Rare Species From South-Eastern Australia

Abstract

Eucalyptus paliformis is restricted to a small, isolated plateau on the eastern escarpment of south-eastern Australia. Eucalyptus parvifolia populations are scattered discontinuously in a narrow band of nearby grazing land that has been substantially cleared over the last 100 years. Allozyme diversity was examined in six of the seven known populations of E. paliformis and in all the eight known populations of E. parvifolia to help assess the potential for the survival of these species under current conditions of management. Levels of genetic diversity in E. paliformis are comparable to levels in other eucalypts of restricted distribution and, in conjunction with its large population sizes, are likely to be adequate for its survival. The greatest threat to E. paliformis is its localised distribution, which renders it susceptible to extinction by disturbance. By contrast, the levels and distribution of diversity in E. parvifolia, and estimates of migration between populations, suggest that the high variability measured in this species may be a consequence of a once more continuous distribution. The recent dissection of its range through clearing is likely to lead to a decline in levels of genetic diversity in E. parvifolia, which, when combined with destruction of the habitat where it can best outcompete other eucalypts, suggests its survival is threatened.