ABSTRACT Phenology is defined as the study of the timing of biological events and the biotic and abiotic factors that trigger them. This study reports a description of the phenology of Byrsonima pachyphylla and B. verbascifolia in an ecotonal area between the Cerrado and Amazonia biomes in the Brazilian state of Tocantins, to contribute to a better understanding of their autoecology in this region. Two populations of 15 adult individuals of each species, randomly selected in a Cerrado area in Porto Nacional, Tocantins, were surveyed for 12 months. Percentages were estimated of leaf flush, young, mature, and senescent leaves (vegetative phenology), flower buds, open flowers, green and ripe fruits (reproductive phenology) present in the canopy, as well as the synchrony of the reproductive phenophases. The vegetative and reproductive phenological events were seasonal and occurred mainly at the end of the dry season and during the transition from the dry to the rainy season. Considering the vegetative and reproductive phenology, B. pachyphylla was classified as “evergreen with continuous growth” and as a late-flowering species, whereas B. verbascifolia was classified as “evergreen with seasonal growth” and as an early-flowering species. The reproductive phenological activity of the species exhibited high synchrony. The results suggest that the vegetative and reproductive events are peculiar to each species and represent effective strategies for their survival in the Cerrado, which is markedly seasonal.

RESUMO A fenologia estuda o período de ocorrência de eventos biológicos e o que os estimulam, em relação a fatores bióticos e abióticos. A presente investigação teve como objetivo descrever a fenologia de Byrsonima pachyphylla e de B. verbascifolia em uma área ecotonal entre os Biomas Cerrado e Amazônia no estado do Tocantins com a finalidade contribuir para o melhor entendimento de sua autoecologia nessa região pouco estudada. Trinta indivíduos adultos de cada espécie, escolhidos aleatoriamente em área de Cerrado stricto sensu em Porto Nacional, Tocantins, foram acompanhados quinzenalmente durante doze meses. Foram estimadas as porcentagens de brotações e folhas em diferentes estágios de desenvolvimento (fenologia vegetativa), de botões florais, flores abertas, frutos verdes e maduros (fenologia reprodutiva), bem como a sincronia das fenofases reprodutivas. Os eventos fenológicos vegetativos e reprodutivos foram sazonais e ocorreram principalmente no final do período seco e início do chuvoso. A fenologia vegetativa de B. pachyphylla foi classificada como sempre verde com crescimento contínuo e sua floração como tardia, apresentando este evento principalmente no período seco. B. verbascifolia foi classificada como sempre verde com crescimento sazonal e apresentou produção de flores na transição entre o período seco e o chuvoso sendo considerada uma espécie de floração precoce. A atividade fenológica reprodutiva das espécies apresentou alta sincronia. Os resultados sugerem que os eventos vegetativos e reprodutivos são peculiares a cada espécie e estrategicamente eficientes para sua sobrevivência no Cerrado marcadamente sazonal.

ABSTRACT Background: Neotropical species lack autecological information. Among these, are phenological studies, which help to understand forest dynamics and provide important contributions to the collection, restoration, and conservation programs. This research aimed to characterize the vegetative and reproductive phenological behavior of neotropical species Geoffroea spinosa Jacq. in a seasonally dry tropical forest, as well as to verify if there is a correlation between phenophases and environmental parameters. Twenty individuals were accompanied monthly for two years, to detect and tally the presence of floral buds, flowers, immature fruits, ripe fruits, leaf emergence, presence of mature leaves, and defoliation. A semi-quantitative evaluation was carried out with the Fournier method. Results: The results showed that the population had synchrony of reproductive events, with more than 50% of the individuals blooming and fruiting during the same time interval. Furthermore, the circular statistical test indicated a high seasonality for reproductive events (r ≥ 0.50 and p < 0.001). Among the vegetative events, all were classified as non-seasonal (r < 0.5). G. spinosa, showed a significant correlation (p ≤ 0.05) for all meteorological variables evaluated. Conclusion: The reproductive phenophases of G. spinosa showed strongly seasonal behavior, unlike vegetative events. the period between mid-February and the end of March was the most propitious for fruit collection. No seasonality was observed for the vegetative events. The species proved to be sensitive to El niño conditions. Follow-up phenological studies associated with meteorological variables are important for a better understanding of the dynamics of vegetative behavior in response to climate change.

Resumo Este trabalho objetivou estimar a diversidade genética de três populações de Elaeis guineensis no Estado do Rio Grande do Norte, bem como verificar a diminuição do tamanho efetivo da população. A população com maior polimorfismo foi a MAT (Mata), com 57 locos (72%), seguida pela RIA (Riacho), com 54 locos (68%), e HOR (Horta), com 34 locos (43,03%). A população RIA mostrou-se a mais diversificada geneticamente, com índices de diversidade de Nei (h = 0,28) e índice de Shannon (I = 0,41). Houve alta diferenciação genética entre as populações (AMOVA, análise de variância molecular = 42%), que foi separada em três grupos genéticos distintos, de acordo com uma análise bayesiana. Houve uma diminuição significativa da população (P <0,05) para a população HOR no modelo IAM (modelo de alelos infinitos) e SMM (modelo de passos de mutação), e para a população RIA no IAM. Os dados obtidos neste estudo podem apoiar projetos de conservação ex situ para Elaeis guineensis, contribuindo para a seleção de genótipos e seu uso sustentável.

Abstract This study aimed to estimate the genetic diversity of three Elaeis guineensis populations in Rio Grande do Norte state, as well as to verify the decreases in effective population size. The population with the highest polymorphism was MAT (Mata) with+ 57 loci (72%), followed by RIA (Riacho) with 54 loci (68%) and HOR (Horta) with 34 loci (43.03%). The RIA population was shown to be the most genetically diverse, with Nei (h = 0.28) and Shannon (I = 0.41) diversity indices. There was high genetic differentiation among populations (AMOVA, analysis of molecular variance = 42%), which was separated into three distinct genetic groups according to a Bayesian analysis. There was a significant population decrease (P < 0.05) for the HOR population in the IAM (infinite allele model) and SMM (stepwise mutation model), and for the RIA population in the IAM. The data obtained in this study may support ex-situ conservation projects for Elaeis guineensis, contributing to the selection of genotypes and their sustainable use.