The roles of rainfall, soil properties, and species traits in flowering phenology along a savanna-seasonally dry tropical forest gradient

Abstract

We investigated flowering phenology in a semiarid macroclimate along an environmental gradient encompassing neotropical savanna, transition, and seasonally dry tropical forest (SDTF) areas in the Chapada Diamantina Mountains, northeastern Brazil. We expected to find divergence in flowering patterns between the plant communities studied that would be explained by distinct functional traits selected by differences in rainfall volumes and soil properties. Bud and flower productions were monitored in 809 individuals between January 2010 and March 2012. The savanna exhibited a continuous flowering pattern, while the transition and SDTF areas showed seasonal flowering associated with rainfall. Environmental variables and plant traits (wood densities, water potentials, and water storage capacities) were related to the observed flowering strategies of woody species. The high diversity of functional groups in the savanna was determined by higher plant water potentials that were related to low wood densities and the availability of soil water. The role of rainfall, especially the rainfall volumes during the dry season, is critical in defining different flowering patterns at the community level. The physical properties of the soil selected the presence of species with distinct water-use strategies (low wood density species in savanna areas, and high wood density species in the transition zone and forest), which in turn affected their flowering.

Vegetative and reproductive phenology in a tropical grassland–savanna–forest gradient

“…In seasonal tropical regions, the primary factor controlling and regulating phenological events is climate, especially precipitation, although temperature and photoperiod also play important roles (Borchert, 1998; Morellato et al, 2000; Borchert et al, 2005). Precipitation is essential as it regulates seasonality and water availability, and thus has a strong influence on tropical plant phenology (Méndez‐Alonzo et al, 2013; Morellato et al, 2016; Neves et al, 2017). However, biotic selective pressures such as herbivory, competition for pollinators and seed dispersers, and abiotic factors including fire and soil depth, fertility, and water availability also influence plant phenological responses and patterns (Aide, 1988; Cardoso et al, 2012; Lamarre et al, 2014; Morellato et al, 2016; Le Stradic et al 2018; Pillon et al, 2020).…”

Leaf trait variability maintains similar leaf exchange rhythms in Hirtella glandulosa Spreng. (Chrysobalanaceae) populations growing on contrasting soil types in the Brazilian Atlantic Forest

“…Natural environments can impose filters that select certain trait combinations (Carlucci et al 2014). Phenological traits, for example, are marked by the temporal variation of factors such as rainfall and day length (Cardoso et al 2012;Rossatto et al 2013;Neves et al 2017;Souza and Funch 2017). The leaf budding is mainly controlled by day length in environments where plant water balance remains positive throughout the year (Borchert et al 2005;Calle et al 2010;Souza and Funch 2017).…”

“…The leaf budding is mainly controlled by day length in environments where plant water balance remains positive throughout the year (Borchert et al 2005;Calle et al 2010;Souza and Funch 2017). The rainfall volumes and soil properties have also been well documented as defining factors of leaf turnover rhythms in tropical plant species (Reich and Borchert 1984;Reich 1995;Valdez-Hernández et al 2010;Cardoso et al 2012;Rossatto et al 2013;Neves et al 2017). To understand such interactions, it is necessary to analyze traits that indirectly affect growth, reproduction, and plant survival (Violle et al 2007;Vieira et al 2021).…”

Seasonality and the Relationships Between Reproductive and Leaf Phenophases In Myrtaceae Using Field and Herbarium Data

“…The relationship between phases was evidenced, mainly in species showing more restricted distributions such as C. eugenioides var. desertorum and P. schenckianum -both more frequent in caatinga environments (Oliveira et al, 2012;Landrum, 2017), where seasonal water restrictions are strong drivers of plant ecological strategies (Neves et al, 2017). The field data of E. punicifolia reveals the initial development of young leaves, with flower bud development occurring slightly later (Moraes et al, 2017).…”