Reproductive phenology of aquatic macrophytes in the Cerrado-Pantanal ecotone

Abstract

Studies of plant phenology have been performed predominantly with terrestrial species and rarely so with aquatic communities. Such plants are fundamental for the aquatic ecosystems, representing a valuable source of resources when they are scarce in terrestrial environments for the fauna. Studies of phenology help to understand the reproduction rhythms of plant communities and provide fundamental support to management and conservation. This study aimed to describe the reproductive phenology of 15 species of aquatic plants and determine how it is related to climatic factors and physicochemical variables of water. Plants were collected every 15 days throughout a single year, from two ponds in the Cerrado-Pantanal ecotone, Central-West Brazil. Species were observed in flower and fruit throughout the year with varying phenophases among life forms (amphibious, emergent, rooted, floating and rooted submerged). Photoperiod stood out among climatic variables for flowering and fruiting times. Phenophases were explained by climatic factors, as well as by physicochemical variables of the water. Nitrogen and pH were the variables most related to the highest number of phenophases of different life forms. Such information is relevant to understanding how physicochemical alterations to water by pollution, eutrophication and siltation, among others, can change the phenology of aquatic macrophytes.

Among‐species variation in flower size determines florivory in the largest tropical wetland

“…Nevertheless, our results indicate a general trend of higher florivory levels in terrestrial plants and, specifically, a higher percentage of flowers attacked on aquatic plants during the rainy season. Flower blooming of aquatic plants in the Pantanal peaks during the rains, whereas blooming of terrestrial plants is concentrated at the end of the dry season (Damasceno‐Junior et al, 2005; Lima and Damasceno‐Junior, 2020; Simão et al, 2021). Our results for florivory seem to be in accordance with blooming peaks for each substrate, reflecting higher resource availability for florivores.…”

“…The Pantanal is the world's largest tropical wetland, presenting an intense environmental seasonality marked by dry and rainy seasons and a periodic flooding regime, temporal patterns that eventually determine plant species distribution, phenology, and trait selection in this ecosystem (Junk et al, 2006; Ferreira‐Júnior et al, 2016; Catian et al, 2019; Simão et al, 2021). The intensity and timing of rains and floods also create a diversity of permanently or temporarily flooded habitats, some with low flooding and others never flooded (forming an aquatic–semiaquatic–terrestrial continuum), which ultimately determine the dominance of aquatic or terrestrial plants (Adamoli, 1995; Junk et al, 2006; Scremin‐Dias et al, 2011).…”