Co‐occurrence patterns in a diverse arboreal ant community are explained more by competition than habitat requirements

Abstract

A major goal of community ecology is to identify the patterns of species associations and the processes that shape them. Arboreal ants are extremely diverse and abundant, making them an interesting and valuable group for tackling this issue. Numerous studies have used observational data of species co‐occurrence patterns to infer underlying assembly processes, but the complexity of these communities has resulted in few solid conclusions. This study takes advantage of an observational dataset that is unusually well‐structured with respect to habitat attributes (tree species, tree sizes, and vegetation structure), to disentangle different factors influencing community organization. In particular, this study assesses the potential role of interspecific competition and habitat selection on the distribution patterns of an arboreal ant community by incorporating habitat attributes into the co‐occurrence analyses. These findings are then contrasted against species traits, to explore functional explanations for the identified community patterns. We ran a suite of null models, first accounting only for the species incidence in the community and later incorporating habitat attributes in the null models. We performed analyses with all the species in the community and then with only the most common species using both a matrix‐level approach and a pairwise‐level approach. The co‐occurrence patterns did not differ from randomness in the matrix‐level approach accounting for all ant species in the community. However, a segregated pattern was detected for the most common ant species. Moreover, with the pairwise approach, we found a significant number of negative and positive pairs of species associations. Most of the segregated associations appear to be explained by competitive interactions between species, not habitat affiliations. This was supported by comparisons of species traits for significantly associated pairs. These results suggest that competition is the most important influence on the distribution patterns of arboreal ants within the focal community. Habitat attributes, in contrast, showed no significant influence on the matrix‐wide results and affected only a few associations. In addition, the segregated pairs shared more biological characteristic in common than the aggregated and random ones.

Ant diversity in Brazilian tropical dry forests across multiple vegetation domains

“…We argue that the historical component is indeed important, however it must be coupled with the influence of recent ecological conditions inherent from the surrounding vegetation domains, such nesting site availability and colony establishment (e.g. Guimarães et al 2007, Andersen 2008), as well as species interactions outcomes (Cerdá et al 2013, Camarota et al 2016), which are likely to be responsible for the compositional uniqueness we observed in the ant community among vegetation domains.…”

“…At the local scale, interspecific interactions (e.g. competition, mutualism), resource availability, and environmental variables are often described as the major drivers of ant community structure (Srivastava 1999, Baccaro et al 2012, Camarota et al 2016. Examples of environmental variables include tree richness, height, and abundance (Ribas et al 2003, Klimes et al 2012, Sousa-Souto et al 2016, variation in canopy coverage (Neves et al 2013), and characteristics of soil structure (Schmidt et al 2013).…”

Connectivity explains local ant community structure in a Neotropical forest canopy: a large‐scale experimental approach

“…) or species interactions (Blüthgen and Stork , Camarota et al. ), also significantly influence arboreal ant community structure.…”

Effects of isolation on ant assemblages depend on microhabitat

“…Alternatively, other ecological factors, such as competition (Camarota et al. ), might play a larger role than habitat limitations in shaping ant communities in this system.…”

“…Although basal area is an effective proxy for tree size in other systems (O'Brien et al 1995), as trees grow in the floating marsh, the added weight causes them to sink deeper into the floating mat creating inconsistencies between dbh and root area. Alternatively, other ecological factors, such as competition (Camarota et al 2016), might play a larger role than habitat limitations in shaping ant communities in this system.…”