The germination requirements of a broad spectrum of common species found in grassy woodlands and forests in the New England region of northern New South Wales were tested in a series of replicated growth-cabinet experiments. The effects of dark/diurnal light and smoke/no smoke were measured on 65 species in an orthogonal experiment, 21 of which were retested after storage for 12 months. The effect of storage for several years was also assessed under a diurnal light regime. In addition, the effects of preimbibition heat (80˚C), and chilling on germination were also measured. A single temperature regime (15˚C night/25˚C day) was used in all treatments for comparative purposes. Most species had high viability and germinability under a diurnal light regime. Small shrub species included, however, a large proportion of species with entrenched dormancy. Light enhanced germination of 21 species significantly, whereas dark stimulated germination of only eight species. Heat and cold treatments also stimulated some germination but more often inhibited germination or produced no effect. Smoke stimulated germination, relative to other cues, in only one species (Ajuga australis) and more often inhibited germination or produced no effect. The relationship between variation in germination (stimulation, no effect or inhibition) of species in six growth-form classes was tested by using contingency tables for each treatment. No significant relationship between growth form and the effects of light, smoke or chilling was detected. Preimbibition heat effects were, however, significantly different among growth forms. Subshrubs showed a higher than expected proportion of species with a heat stimuli while herbaceous species showed a higher than expected proportion of species inhibited by preimbibition heat. Germinability generally increased in herbaceous species when stored at ambient temperatures while it remained relatively constant in woody species. Conversely, viability decreased in herbaceous species but remained relatively more constant in woody species. The effects of seed storage and high germinability suggest that most perennial herbaceous species have transient or short-term persistent seed banks. Germinability, with and without cues, was also negatively correlated with increasing seed size and larger growth forms. These traits might be related to the need for woody species, with soil-stored seed banks, to spread establishment risks in an environment where herbaceous competition and herbivory are likely to be important selection factors.

Interventions designed to provide social support, heighten safety at activity areas and improve park infrastructure may provide opportunities to increase physical activity among seniors.

Field experiments examined herbaceous seedling emergence and survival in temperate grassy woodlands on the New England Tablelands of New South Wales. Effects of intensity of previous grazing, removal of ground cover by fire or clearing, burial of seeds, grazing and seed theft by ants on seedling emergence and survival were studied in two field experiments. Thirteen species with a range of traits were used in the experiments and their cumulative emergence was compared with laboratory germination studies. Field emergence correlated to laboratory germination but all species had lower emergence in the field. Little natural emergence of native species was observed in the field in unsown treatments. Short-lived forbs had the highest emergence, followed by perennial grasses; rhizomatous graminoids and perennial forbs had the lowest emergence. Soil surface and cover treatments did not markedly enhance emergence suggesting that intertussock spaces were not prerequisites for forb emergence. No consistent pattern of enhanced emergence was found for any treatment combination across all species. Seedling survival varied among species, with perennial grasses and short-lived forbs having the highest seedling mortality. Low mortality rates in the graminoids and rhizomatous forbs appeared partially to compensate for lower seedling emergence. All perennial grasses and some short-lived forbs showed increased risk of mortality with grazing. Differences in emergence and survival of species were related to ground cover heterogeneity, soil surfaces and, to some extent, herbivory. The complexity of these patterns when superimposed on temporal variability suggests that no generalizations can be made about the regeneration niche of herbaceous species groups. Strong recruitment limitation and partitioning of resources in the regeneration niche may reduce competition among native species and explain the high species richness of the herbaceous layer in the temperate grassy communities of eastern Australia.

Field experiments were designed to examine tree and shrub seedling emergence in temperate grassy woodlands on the New England Tablelands. The effects of study sites, intensity of previous grazing, removal of ground cover by fire or clearing, burial of seeds and ant seed theft on seedling emergence were tested in two field experiments. Six tree and seven shrub species were used in the experiments and their cumulative emergence was compared with laboratory germination studies. All species used in field experiments had lower cumulative emergence than those in laboratory germination studies despite prolonged periods of above average rainfall before and after seeds were sown. Eucalypt species emerged faster in the field than the shrub species and generally attained higher cumulative emergence than the shrubs. Spatial effects of sites and patches within sites, and of previous grazing history did not strongly influence patterns of seedling emergence in most species. Ground and litter cover generally did not enhance or suppress the emergence of seedlings, although the removal of cover in recently grazed areas enhanced the emergence of some species. Burning enhanced the emergence of some tree and shrub species where plots had more fuel and intense fires, but this effect was not strong. Compared with other treatments, seedbed manipulations produced the strongest effects. In the absence of both invertebrate and vertebrate predators, seedling emergence was lower for surface-sown seed, compared with seed sown on scarified soil surfaces. Higher seedling emergence of buried seeds in the presence of invertebrate predators probably resulted from the combined effects of predator escape and enhanced moisture status of the germination environment. Some promotion of emergence was achieved for all species in most sown treatments probably as a result of a prolonged above average rainfall. In contrast, the natural recruitment of trees and shrubs was negligible in experimental plots, highlighting the importance of seed supply and dispersal as ultimate determinants of recruitment.

No abstract