Fenologia reprodutiva no limite norte da Mata Atlântica: importância dos fatores ambientais e evolutivos

Abstract

Phenology studies the patterns of recurrent events in living organisms and their relationship with extrinsic and intrinsic factors. Phenological studies are crucial for the management and preservation of ecosystems, as they provide valuable information about the availability of resources over time and space. At higher latitudes, plant phenology is mainly driven by variations in day length. However, in less seasonal regions near the equator, phenology is expected to be more influenced by other environmental factors, such as precipitation, or by evolutionary factors, such as phylogeny. Due to the scarcity of phenological data on the northern limit of the Atlantic Forest in Brazil, this study aims to reduce the gap by testing the hypotheses that climate and evolutionary history structure the reproductive patterns of plant communities at low latitudes, close to the equatorial line. To this end, we monitored 1,092 individuals from 93 species every two weeks in two Conservation Units (CUs) in Rio Grande do Norte, Brazil. We collected qualitative and quantitative data for four reproductive phenophases (flower bud, anthesis, immature fruit, and mature fruit) and analyzed them in conjunction with climate and evolutionary history (phylogeny) data. Our study tested: (i) whether there is seasonality and synchrony of the plant species that make up the two observed communities, and (ii) whether the reproductive response of these species is influenced by climate or phylogeny. The results show that environmental factors were the main predictors of phenology. The community showed seasonality and synchrony in its flowering and fruit development phenophases. Longer day length and more intense precipitation were the most important environmental triggers for the occurrence of flower buds and anthesis, while warmer temperature and higher precipitation were important for fruit development. Fruiting was continuous, and the production of mature fruits was better explained when considering the evolutionary history of the lineages, environmental factors, and the shared influence between them. The present research provides unprecedented and crucial data on the phenology of species at the northern limit of the Atlantic Forest, in addition to providing insights into the influence of environmental and evolutionary factors in determining the phenophase of plant species.