Traços funcionais de ambientes ciliar e não ciliar em Mata Atlântica

Abstract

Functional traits are characteristics classified as morphological, physiological or phenological and that can be measured. These have a strong relationship with ecological processes and the functioning of communities, as well as ecosystems, exposing feedbacks to the environmental state or changing characteristics of the environment. This research aimed to analyze the structural behavior of the functional traits of tree species in riparian and non-riparian areas of the Atlantic Forest, in order to contribute to a functional ecological approach in different environmental contexts. For this purpose, six functional traits were used: leaf area, leaf thickness, specific leaf area, leaf dry matter content, leaf composition and maximum height; three ecological groups: pioneer, early secondary and late secondary; six soil variables: hydrogenic potential, phosphorus, calcium, magnesium, potassium and aluminum. The Shapiro-Wilk test was applied to assess whether the data meet the statistical assumptions. The functional traits were submitted to a correlation matrix by the Spearman coefficient, then the phenotypic plasticity index was calculated for the functional traits between environments. The Friedman and Kruskal-Wallis test was used to verify if there was a difference between the values of the functional traits between environments, ecological groups and soil variables. The analysis of principal components was carried out, which made it possible to carry out analyzes between multiple variables of functional traits, ecological groups and soil variables. Non-metric multidimensional scaling analysis was applied to assess the distribution of nutrient levels between the study areas. The functional diversity calculation was based on the estimators: functional richness, functional evenness, functional divergence and functional dispersion, which compared the preserved riparian and non-ciliary environments. Functional composition across communities was assessed by the weighted average of community-level trait values. It was identified that the environments diverge between the functional traits, the traits by ecological groups, between the estimators of functional diversity and also between the levels of nutrients in the soil. The riparian environment showed higher values for morphological functional traits, greater spacing between individuals, greater functional uniformity and homogeneity between the abundance of species. The ciliary context favored plasticity among the functional traits. The non-riparian environment presented high values of functional divergence and functional equitability, competitiveness for the use of resources with high vertical investment and a tendency to group functional strategies. The high abundance of individuals may be influencing the plasticity in this community. The areas diverge between nutrient levels of soil, with low values for all nutrients in the areas. Soil variables alone contribute little to changes in functional traits.