Lifetime reproductive allocation has been characterised across 14 iteroparous woody perennials in fire-prone sclerophyll vegetation near Sydney, Australia. These data have been used to explore how species with different life history strategies vary in their investment in growth versus reproduction across their lifespans and how relative investment in different reproductive tissue types shifts across species.
Such data broaden our understanding of the interplay between species traits, demographic outcomes, and ecological strategies.
Results/Conclusions
Reproductive costs were large, especially when accessory costs are included. At peak they seemed sufficient to bring an end to the accumulation of foliage. Reproductive allocation as a proportion of surplus energy continued to increase through the lifespan for most species, but leaf area asymptoted or even declined in many species, leading to an earlier plateau in total seed output. Species that reached peak reproduction later during the fire cycle tended to have taller maximum heights and lower maximum reproductive allocation. Relations to other traits, including wood density, LMA and seed size, were not tidy.
Moving to broader comparisons, theory predicts that the influence of leaf construction cost on growth rate should change with the size of the plant, and this is supported by synthesis of literature results. Theory predicts also that seed size should be evolutionarily coordinated with size at adulthood, but this coordination should be quite loose and should depend on the context of competition among growing plants. Generally demographic patterns are outcomes from the expression of traits in a particular setting -- it is possible for the same species to show different demography in different places, and for species with different traits to show similar demography.