Pteropus alecto uses landscape patchiness at two scales: firstly, between broad vegetation types (i.e. eucalypt open forest/savanna woodland versus rainforest vegetation); secondly, within vegetation types. Radio-collared Pteropus alecto selected foraging sites that were richer in flower or fruit resources than floristically similar sites and moved through the landscape in response to the flowering and fruiting of a number of plant species occurring in different vegetation types. Abundance of P. alecto within four monitored rainforest patches and the outside vegetation fluctuated substantially during the study. Overall, P. alecto was more abundant in the rainforests than in the surrounding vegetation. P. alecto foraged on the flowers and fruit from 23 species in 11 families.

Monsoon rainforests occur as scattered patches within a landscape dominated by eucalypt savannas across the wet–dry tropics of northern Australia. This study formed part of a larger project that investigated the interactions between frugivores and monsoon rainforest patches in the Top End of the Northern Territory. Phenological patterns in a set of 12 wet monsoon forests (WMF) and four dry monsoon forests (DMF) were examined by monitoring individuals of more than 100 species over 30 months. Phenological patterns of both WMF and DMF were closely related to the strongly seasonal climate. Leaf flush occurred before the onset of the wet season in WMF, and coincided with the onset of the wet in DMF. Major flowering peaks coincided with leaf flush in both forest types. Fruiting was concentrated in the wet season in both forest types, but fruiting peaks of WMF and DMF were separated by 3–4 months. Variations in fruiting patterns among forest types, patches, seasons and groupings of plant species (based on life form and ecological positioning) provide a mosaic of food resources for frugivores. This has important implications for the conservation and maintenance of the frugivore–rainforest system in northern Australia.

No abstract

Intraspecific synchrony in the phenology of tropical forest trees has implications for satiation of browsers and seed predators, pollination, dispersal and interpreting plant responses to environmental cues and stresses. Community phenological studies have been constrained in their consideration of these issues by the lack of concise quantitative measures of intraspecific synchrony. We propose a novel application of Colwell's predictability indices to overcome this deficiency. Its application is demonstrated by evaluating the leaf and reproductive phenologies of 8–16 individuals of each of 20 monsoon forest tree species from northern Australia monthly for 30 mo. The indices yielded substantial additional information over that provided by summaries averaged amongst conspecifics. Marked intraspecific asynchronies in leaf flush or flowering occurred in five evergreen species and two deciduous fig species, and were associated with prolonged individual commitments to these states. Five partly deciduous species exhibited marked intraspecific variation in the seasonal extent of leaf loss. We interpret the observed variation in intraspecific synchrony in terms of contrasting water-use and pollination strategies. The synchronicity indices are concise and robust to small and variable sample sizes, and may thus enhance studies of species-rich assemblages.

Seed germination traits of seasonal rainforest species differ from permanently moist evergreen rainforest species due to the prolonged seasonal drought. We investigated whether seed germination traits used to categorise evergreen rainforest species into pioneer and climax guilds were applicable to seasonal rainforest species. Seed dormancy, light requirements for germination and seed storage types of five climax and thirteen pioneer species of a coastal vine thicket were studied. Results were compared with published studies of evergreen rainforest species. Evergreen rainforest pioneer species are typically dormant, require light to germinate and tolerate desiccation, whereas climax species are typically non-dormant, tolerate shade during germination and are sensitive to desiccation. In seasonal rainforest we found that a high proportion of pioneer species had seeds that were non-dormant (62%), and a high proportion of pioneer species germinated equally well in light and dark conditions. In seasonal rainforest, we found that the majority of climax species had desiccation tolerant seeds, whereas in evergreen rainforest the proportion of climax species producing desiccation sensitive seeds is equal to or greater than the proportion of species with desiccation tolerant seeds. In seasonal rainforest species physical, physiological and epicotyl dormancy types were found. Generally, for seasonal rainforest species, the prevalent form of dormancy in pioneer species was physical dormancy whereas physiological dormancy was most common in evergreen rainforest pioneer species with dormancy. Our results suggest that the contrasting seed biology traits that typically apply to pioneer and climax species of evergreen rainforest species don’t typically apply to seasonal rainforest species.