Phenological cycles in the Pantanal woody communities: Responses to climate and soil moisture seasonality

including G. americana, T. aurea, and T. catigua, and 4% of the individuals presented flower or floral buds at an intensity of 1.5%. The PS community presented significant and low interspecific synchrony and a seasonal flowering pattern (rc = 0.27; p = 0.003), with a mean month of concentration in May. This result highlights the constant, although oscillating, activity in flowering in the eighth of the 12 months of the hydrological year. The months with the highest flowering intensity in the dry season (July-August, 1.1–1.3%) did not coincide with the relatively high proportion of active species and individuals in the rainy season (January, 18% and 1.3%, respectively). A reduction in moisture and rainfall from May to August in PS resulted in an increase in flowering inten- sity from 0.5% to 1.13%, which coincided with the blooming of H. heptaphyllus, a typical spe- cies of this community. In the ASDF, flowering episodes were not synchronous among species (rc = 0.38; p = 0.18), and the percentages of species and flowered individuals were low throughout the year. We recorded two flowering peaks, one in September, the driest month, and the other in wet Janu- ary; in both months, the frequency of flowered species was 4%. The annual intraspecific varia- tion in flowering followed the interspecific variation, with January and September corresponding to the months with the maximum frequency of flowering individuals (1.5%). According to the Fournier intensity, the flowering intensity was the highest (0.6%) during dry

September when the soil moisture was the lowest (10%), indicating the activity of M. guianen- sis and T. americana. Flowering seasonality was the phenological event with the greatest difference between com- munities, as indicated by Watson-Williams F tests (Table 1). The IS showed a similar pattern to that found for MF and SHB, communities characterized by a prolonged flood period and monodominance, with flowering concentrated in the dry season. Fruiting. Except for the PS and ASDF communities, all the other five communities exhib- ited interspecific synchrony during the fruiting cycle. According to the Watson-Williams test, seasonality during the fruiting period did not significantly differ among the communities (Table 1). Fruits were observed in the communities throughout the year, which may be attrib- uted to extended fruiting schedules and staggered ripening times. SHB (rc = 0.59, p<0.001) and MF (rc = 0.41, p<0.001) had the strongest seasonal patterns of interspecific synchrony of fruiting among the communities, with the mean months of fruit- ing occurring in the dry (September) and wet (December) seasons, respectively (Fig 5A). The few recorded individuals flowering in SHR, followed by high-frequency fruiting, may be due to our monthly monitoring missing the preceding flowering events. In the MF, the frequency of species fruiting was as high in wet December as in dry September (36%), with the event being 17% more intense in September (Fig 5B). Species such as M. guianensis and L. parvifolius

presented fruits during the wet and dry seasons, and others had fruits only in the wet phase, such as A. discolor, Myrcia tomentosa, and N. amazonum. The relatively high percentage of individuals fruiting (18%) coincided with the rainy season in December, approximately three to five months after the flowering peak. This pattern was observed in the monodominant spe- cies V. divergens (S1 Table). The mean fruiting date in the IS was dry September (rc = 0.31, p<0.001), when 36% of the species presented fruits, and the Fournier fruiting intensity was 2.8%. From December to March, during the rainy and flooded periods, fruiting was observed in E. anguifugum, G. amer- icana, H. heptaphyllus, and V. divergens. In the CS community, interspecific synchronism among species (rc = 0.21, p = 0.002) was associated with the mean concentration of fruiting in the rainy season (November). On the other hand, two fruiting peaks were recorded in CS (Fig 5B), one during the dry season in Sep- tember (15.3%), when the species C. fasciculata, C. americana, Psidium guineense, and T. aurea PLOS ONE Phenological cycles in the Pantanal woody communities PLOS ONE | https://doi.org/10.1371/journal.pone.0316011 February 7, 2025 14 / 30