Trait-environment Relationship in Tadpole Communities of the Southern Atlantic Forest

The diversity of functional traits can be evaluated by analyzing an individual's morphological, physiological, and behavioral attributes, revealing the effect of environmental filters on communities. However, the role of different spatial scales in environmental evaluation over ecological attributes is complex and poorly studied in tadpole communities. Here, we investigated the association between micro (local) and macro (landscape) variables and the morphological traits of tadpoles in the southern region of the Brazilian Atlantic Forest. We sampled 28 waterbodies (ponds and streams) and evaluated 2861 individuals of 22 anuran species. Our sampling reached a wide geographic area across three states in southern Brazil. We measured the physicochemical characteristics of the water, as well as microhabitat and landscape environmental descriptors. Eighteen morphological traits were evaluated in individuals for each tadpole species. We performed RLQ and fourth-corner analyses to determine the patterns of trait-environment relationships and the local and landscape variables that influence the morphological characteristics of tadpoles. We found that morphological traits are mainly associated with physicochemical and microhabitat attributes and are distinct between ponds and streams. In ponds, tadpole traits exhibited greater association with water depth, pH, and the presence of vegetation, whereas in streams they were driven by several water physicochemical components and microhabitat composition. Our results indicate that local components of habitat (water characteristics and microhabitat) have a greater influence over functional traits of tadpoles than landscape in both ponds and streams. Furthermore, we also found possible adjustments in the functional traits of tadpoles related to the physicochemical characteristics of the water and microhabitat.