Canopy Openness Enhances Diversity of Ant–Plant Interactions in the Brazilian Amazon Rain Forest

Abstract

In closed‐canopy tropical forest understory, light availability is a significant determinant of habitat diversity because canopy structure is highly variable in most tropical forests. Consequently, variation in canopy cover affects the composition and distribution of plant species via creating variable light environments. Nevertheless, little is known about how variation in canopy openness structures patterns of plant–animal interactions. Because of the great diversity and dominance of ants in tropical environments, we used ant–plant interactions as a focal network to evaluate how variation in canopy cover influences patterns of plant–insect interactions in the Brazilian Amazon rain forest. We observed that small increases in canopy openness are associated with increased diversity of ant–plant interactions in our study area, and this change is independent of plant or ant species richness. Additionally, we found smaller niche overlap for both ants and plants associated with greater canopy openness. We hypothesize that enhanced light availability increases the breadth of ant foraging sources because variation in light availability gives rise to plant resources of different quality and amounts. Moreover, greater light availability promotes vegetative growth in plants, creating ant foraging ‘bridges’ between plants. In sum, our results highlight the importance of environmental heterogeneity as a determinant of ant–plant interaction diversity in tropical environments.

Phylogenetic Overdispersion in Lepidoptera Communities of Amazonian White‐sand Forests

“…The low overlap in herbivore species composition between highly contrasted habitats may be explained by changes in host plant species composition and differences in habitat structure (such as canopy openness, see Dáttilo & Dyer ). Previous studies have shown that plant species composition shows strong turnover among local communities (Tuomisto et al .…”

Weak relationships between leaf phenology and isohydric and anisohydric behavior in lowland wet tropical forest trees

“…). Vegetative phenology, specifically the rhythm and intensity of leaffall and emergence, has a major influence on ecosystem processes and community dynamics, including water, nutrient and carbon cycling, biomass accumulation, plant growth and survival, population demography, and numerous trophic interactions ( e.g ., Forrest & Miller‐Rushing , Dáttilo & Dyer , Souza et al . ).…”

“…For instance, large variability in phenologic and leaf longevity was found in a long-term study of 23 tree species that grew in different communities within an Amazonian rain forest complex in Venezuela , and a wide range of leaf water potentials was found for 71 species within two wet forests in French Guiana (Mar echaux et al 2015). Vegetative phenology, specifically the rhythm and intensity of leaffall and emergence, has a major influence on ecosystem processes and community dynamics, including water, nutrient and carbon cycling, biomass accumulation, plant growth and survival, population demography, and numerous trophic interactions (e.g., Forrest & Miller-Rushing 2010, D attilo & Dyer 2014, Souza et al 2014. Therefore, more systematic measurements of vegetative phenology and ecophysiological characteristics are necessary to advance research on leaf habit and water regulation behaviors based on plant functional traits of tropical wet forest trees.…”

Natsumushi: Image measuring software for entomological studies

“…In ecological studies, canopy openness and ground plant coverage are commonly used to describe the local environmental properties (Wiens et al . ; Dátilo & Dyer ; Ohwaki et al . ).…”