Abstract Although ferns have a prominent floristic position with their richness center in Atlantic Forest in Brazil, the effect of climate on their phenophases is still poorly known. This group shows different phenological patterns due to the great latitudinal extent, the strong climatic seasonality of this forest, and the leaf dimorphism found in some species. In this scenario, we evaluated the phenological events of Elaphoglossum macrophyllum and related them to climatic factors. Fertility, leaf renewal, and leaf senescence in E. macrophyllum were analyzed based on the monthly survey of 152 plants growing for two years in the subtropical Atlantic Forest, Brazil. The three analyzed phenophases showed the same intra-annual pattern regarding continuity, regularity, and seasonality along the two years, revealing a phenological pattern for the specie. The generalized additive models for location, scale, and shape (GAMLSS) indicated that photoperiod was the most important trigger for fertility and leaf renewal. Temperature, as an important phenology modulator, was related to leaf renewal and senescence. Our data indicate that E. macrophyllum, an endangered species in southern Brazil, withstands the consequences of seasonal climatic variations without the individual mortality, total leaf shedding, or fertility loss.

Resumo Embora as samambaias tenham posição florística de destaque, com seu centro de riqueza na Mata Atlântica brasileira, o efeito do clima sobre suas fenofases ainda é pouco conhecido. Este grupo apresenta comportamentos diferenciados em sua fenologia devido à grande extensão latitudinal, à forte sazonalidade climática desta mata e ao dimorfismo foliar presente em algumas espécies. Nesse cenário, avaliamos os eventos fenológicos de Elaphoglossum macrophyllum e os relacionamos a fatores climáticos. Fertilidade, renovação foliar e senescência foliar em E. macrophyllum foram analisadas a partir do levantamento mensal de 152 plantas crescendo por dois anos na Mata Atlântica subtropical, Brasil. As três fenofases analisadas apresentaram comportamento recorrente quanto à continuidade, regularidade e sazonalidade nos dois anos, evidenciando um padrão fenológico para a espécie. Os modelos aditivos generalizados para localização, escala e forma (GAMLSS) indicaram que o fotoperíodo foi o gatilho mais importante de fertilidade e renovação foliar. A temperatura, como importante modulador da fenologia, esteve relacionada à renovação e senescência foliar. Nossos dados indicam que E. macrophyllum, uma espécie ameaçada de extinção no sul do Brasil, resiste às variações climáticas das estações sem a morte dos indivíduos, perda total de folhas ou perda de fertilidade.

ABSTRACT Growth rings have been reported for several tropical species under seasonal precipitation regimes and have often been related to leaf phenology. We investigated growth ring distinctiveness, wood markers, and leaf shedding and flushing patterns of 16 tree species from a subtropical seasonal deciduous forest under abundant and well-distributed rainfall regime in southern Brazil. Distinct growth rings were found in 13 species, 10 of which presented clear anatomical boundaries. Seven species were deciduous, five semideciduous and four perennial. Leaf shedding peaked during winter and spring months for the deciduous species, while it peaked during spring and summer months for the perennial and semideciduous species. Leaf flushing peaked in spring and summer for all species. All the deciduous species exhibited growth rings with clear boundaries. Marginal parenchyma, associated or not with other anatomical markers, was present in deciduous species but was not present in species with other leaf shedding patterns. Growth rings in Allophylus edulis, Erythrina falcata, Jacaranda micrantha and Luehea divaricata were described for the first time. The presence of seasonal leaf phenological patterns and growth rings in most of the species suggests that seasonality of the photoperiod and/or temperature influence the development of trees in moist subtropical seasonal deciduous forests.

Eventos vegetativos e reprodutivos de Myrsine lorentziana (Mez.) Arechav., M. guianensis (Aubl.) Kuntze e M. coriacea (Sw.) R. Br. foram avaliados por dois anos, em Floresta Estacional Semidecidual secundária, no Parque Municipal Henrique Luís Roessler, Novo Hamburgo, RS, Brasil. Os eventos fenológicos foram relacionados a variáveis climáticas, e observou-se correlação negativa com a temperatura e o fotoperíodo em M. guianensis e M. coriaceae, na fenofase floração, enquanto na frutificação essa correlação ocorreu em M. lorentziana e M. coriaceae. M. guianensis foi a única espécie que apresentou correlação negativa da fenofase de frutos maduros com o fotoperíodo e a temperatura. Floração e frutos maduros constituíram eventos sazonais nas três espécies, que em conjunto fornecem alimento para a avifauna durante o ano todo. A presença de frutos imaturos, queda foliar e brotamento demonstrou ser um evento contínuo ao longo do ano. Nenhum evento fenológico se correlacionou com a precipitação, resultado esperado em ambientes sem períodos secos regulares.

Vegetative and reproductive events of Myrsine lorentziana (Mez.) Arechav., M. guianensis (Aubl.) Kuntze and M. coriacea (Sw.) R. Br were evaluated for two years in a secondary semideciduous forest at the Parque Municipal Henrique Luis Roessler, Novo Hamburgo, RS, Brazil. Phenologic events were statistically correlated to climatic variables and a negative correlation of temperature and photoperiod with flowering in M. guianensis and M. coriaceae was found whereas in these two variables correlated positively in M. lorentziana and M. coriaceae fruiting. M. guianensis was the only species that showed a negative correlation of phenophase in ripen fruits with the photoperiod and temperature. Flowering and presence of ripen fruits were seasonal events for the three species, although altogether they were a year-round feeding resource for birds. The occurrence of green fruits, leaf fall and leaf appearance seemed to be a continuous event throughout the year. Precipitation did not correlate with any phenologic event, which was expected in environments without regular dry periods.