Ecology of Fire-Tolerant Podocarps in Temperate Australian Forests

Podocarpus drouynianus and P. spinulosus are two unusual conifers restricted to southwestern and eastern Australia, respectively. The species are morphologically similar and genetically closely related to each other but rather distant from other members of the subgenus Foliolatus. Both species have retained ancestral podocarp characteristics such as dioecy, wind pollination, and large, animaldispersed seeds with recalcitrant germination. They also thrive on soils with generally low nutrient content. However, they have several innovations that ensure their success in an environment that would generally be considered unsuitable for podocarps. Both species have much higher leaf length to width ratios than other Podocarpus species: this presumably aids their survival on lowto moderaterainfall sites. They both resprout strongly after fires, and at least for P. drouynianus, seed production is cued by defoliation, and sporophylls are produced most prolifically on new growth one year after fire. The species are unique in the genus as being successfully adapted to a relatively dry, fireprone environment.