Ecophysiological effects of light quality and nitrate on seed germination in species from Western Australia

The spatial structure, age structure and population dynamics of the shrub Kunzea ericoides (A. Rich.) J. Thompson were investigated at Coranderrk Reserve, near Healesville, Victoria, Australia. The shrub is known to be invasive in many areas and, although indigenous to the reserve, has greatly increased its population size and distribution within the reserve in the past 30 years. Dendrochronology showed a constant relationship between age and stem diameter for K. ericoides in the reserve. The spatial structure of the variable stem diameter was investigated by the use of spatial correlograms and results suggested that K. ericoides is spreading via the formation of discrete clumps and gap-phase regeneration. The two main populations in the reserve recruited continuously in time but patchily in space. A simple statistical model for size–frequency data showed that K. ericoides is expanding faster in some areas of the reserve than others. The trend of expansion of K. ericoides may be irreversible. Intensive management of Coranderrk Reserve will be required if K. ericoides is to be controlled and the conservation value of the reserve maintained.