How Do Soil Resources Affect Herbivory in Tropical Plants Along Environmental Gradients? A Test Using Contrasting Congeneric Species

Abstract

Plants adapted to different habitats exhibit differences in functional traits and these characteristics are influenced by soil properties. We tested the hypothesis that soil resource availability influences the functional traits of plants, affecting therefore herbivory levels. We examined three Byrsonima plant species with different life forms that occurred across a distinct edaphic habitat along the Doce River Basin, South-eastern Brazil. We characterize habitats according to soil nutrient concentration and measured functional characteristics of crown architecture, leaf nutrients, sclerophylly, leaf area and leaf density. In addition, we evaluated how these variables influenced herbivory levels of congeneric plants. Our data have shown that species along a gradient of soil nutrients have functional characteristics influenced by habitat, which in turn affected herbivory levels. By comparing species from different life forms but within the same genus along a stress-gradient of continuous habitats, we described a corresponding gradient of plant functional traits and tissue consumption by herbivorous insects.