Phenology of Ficus variegata in a seasonal wet tropical forest at Cape Tribulation, Australia

Abstract

Abstract. We studied the phenology of 198 mature trees of the dioecious fig Ficus variegata Blume (Moraceae) in a seasonally wet tropical rain forest at Cape Tribulation, Australia, from March 1988 to February 1993. Leaf production was highly seasonal and correlated with rainfall. Trees were annually deciduous, with a pronounced leaf drop and a pulse of new growth during the August‐September drought. At the population level, figs were produced continually throughout the study but there were pronounced annual cycles in fig abundance. Figs were least abundant during the early dry period (June‐September) and most abundant from the late dry season (October‐November) through the wet season (December‐April). The annual peak in reproduction actually reflected two staggered peaks arising from gender differences in fig phenology. In this dioecious species, female and male trees initiated their maximal fig crops at different times and flowering was to some extent synchronized within sexes. Fig production in the female (seed‐producing) trees was typically confined to the wet season. Male (wasp‐producing) trees were less synchronized than female trees but reached a peak level of fig production in the months prior to the onset of female fig production. Male trees were also more likely to produce figs continually. Asynchrony among male fig crops during the dry season could maintain the pollinator population under adverse conditions through within‐ and among‐tree wasp transfers.

Phenology of two Ficus species in seasonal semi-deciduous forest in Southern Brazil

“…In spite of this phenophase occur throughout the year, we observed periods of higher syconia production in F. adhatodifolia, as previously reported in other studies on Ficus (Milton et al, 1982;Windsor et al, 1989;Lambert and Marshall, 1991;Spencer et al, 1996;Ragusa-Netto, 2002;Pereira et al, 2007). The population asynchrony would be required for maintenance of the pollinating wasps population (Smith and Bronstein, 1996) while periods of increased production could be related to best time for dispersal and/or seed germination (Milton et al, 1982).…”

“…Although the leaf change can occur seasonally (Spencer et al, 1996;Zhang et al, 2006;Pereira et al, 2007), the reproductive phenology has been registered as asynchronous at the population level (Eshiamwata et al, 2006;Zhang et al, 2006;Pereira et al, 2007;Ragusa-Netto, 2007), probably due to constraints imposed by the obligate mutualism with pollinating wasps.…”

Environmental drivers of leaf phenology in trees of the tropical species Ficus obtusifolia

“…In contrast, in trees of F. variegata growing in a seasonally wet tropical forest, leaf flushing was highly seasonal and correlated with rainfall; trees were annually deciduous, with a pronounced leaf drop and a pulse of new growth during the August-September drought (Spencer et al, 1996). These observations were interpreted as suggesting that leaf phenology is determined, rather than by seasonal changes in temperature and DL, by the annual rainfall and its seasonal distribution (Spencer et al, 1996).…”

“…In contrast, in trees of F. variegata growing in a seasonally wet tropical forest, leaf flushing was highly seasonal and correlated with rainfall; trees were annually deciduous, with a pronounced leaf drop and a pulse of new growth during the August-September drought (Spencer et al, 1996). These observations were interpreted as suggesting that leaf phenology is determined, rather than by seasonal changes in temperature and DL, by the annual rainfall and its seasonal distribution (Spencer et al, 1996). Synchronicity in the foliar exchange of F. thonningii, F. citrifolia (Damstra et al, 1996) and F. variegata (Spencer et al, 1996) was interpreted, based on estimations of water status through rainfall values, as due to water deficit during the dry season.…”

“…These observations were interpreted as suggesting that leaf phenology is determined, rather than by seasonal changes in temperature and DL, by the annual rainfall and its seasonal distribution (Spencer et al, 1996). Synchronicity in the foliar exchange of F. thonningii, F. citrifolia (Damstra et al, 1996) and F. variegata (Spencer et al, 1996) was interpreted, based on estimations of water status through rainfall values, as due to water deficit during the dry season. In contrast, Pereira et al (2007) concluded that measured rainfall and estimated soil water storage probably did not accurately reflect the actual water status of trees of F. citrifolia, in which no relationship was found between the abovementioned variables and leaf exchange.…”