Functional traits in Myrteae species: the role of habitat heterogeneity and genus in humid and seasonal tropical environments

Context. Morphological traits allow for plant persistence in various environments differing in edaphic and climatic aspects, and their values are normally the result of the diversity of genera and species occurring in a certain region. Myrteae, a widespread tribe of Myrtaceae, is found in varied environmental conditions ranging from dry to wet environments; thus, it is a potential study group for understanding trait variation. Aims. Considering that functional-trait variation can be selected by environmental filters, and also be affected by phylogenetic aspects, we used the diversity of the Myrteae group present in different vegetation types in north-eastern Brazil to understand the role of the environment and genus in trait variation. Methods. Two morphological traits, namely, wood density and specific leaf area, were sampled in 29 species from 6 genera in the following four vegetation types: savanna, seasonally dry tropical forest, rupestrian grassland and humid forest. We assessed how variation in the two traits was related to genus and environmental conditions. Key results. The studied species showed trait variation depending on the environment and genus. Wood density was mainly determined by genus, whereas specific leaf area was mostly influenced by the environment. Conclusion. The most important determinant of interspecific trait variation differed between wood density and specific leaf area in this study. Wood density was strongly related to genus, suggesting it is a conserved trait in Myrteae, whereas specific leaf area tended to be more variable. Implications. Our results contribute to understanding the causes of morphological and genetic variability in Myrteae.