Phenological patterns of Ficus citrifolia (Moraceae) in a seasonal humid-subtropical region in Southern Brazil

Abstract

Year-round flowering is widely reported in fig trees and is necessary for the survival of their short-living, specialized Agaonid pollinators. However, seasonality in both fig and leaf production has been noted in almost all published phenological studies. We have addressed the following questions in the present study: (1) Are reproductive and vegetative phenologies seasonal and, consequently, related to climate? (2) Does Ficus citrifolia produce ripe figs year round? (3) Is the fig development related to climate? And, (4) Are reproductive and vegetative phenologies independent? By investigating these questions with a F. citrifolia population over a two-year period, at the southern edge of the tropical region in Brazil, we detected phenological seasonality that was significantly correlated with climate. Our findings can be summarized as follows: (1) Trees became deciduous during the cold and dry months; (2) The flowering onset was asynchronous among individuals, but with moderate concentration during the hot and rainy months; (3) There was a correlation between the onset of flowering and vegetative phenology, with significantly higher crop initiations in individuals with full-leaf canopy; (4) Fig developmental time was longer in cold months; and (5) Ripe fig production occurred year-round and was not correlated with climate. Our results suggest that there are strong selection pressures that maintain the year-round flowering phenology in figs, for we have observed little seasonality in the phenology of such species despite the strong seasonality in the environment.

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).…”

“…Miq.). Ficus citrifolia (subgenus Urostigma) was also considered deciduous (Pereira et al, 2007) in the same region of this study. These variation in leaf dynamics may possibly reflect different adaptations to water deficits in hemi-epiphytic and freestanding species.…”

“…The autoregressive models were selected using Akaike information criterion. More details are available in Pereira et al (2007). In these analyses, the occurrence of phenophase in an individual was considered only the first time it was recorded.…”

“…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

“…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.…”