Diversity studies applied to ant communities have in the past focused on either geographical gradients or local biotic interactions. It is now obvious that local- and regional-level factors can interact to shape the diversity and structure of local ant communities (Local: Savolainen and Vepsäläinen 1989, Savolainen 1990, Vepsalainen and Savolainen 1990; Savolainen 1991; Regional: Kaspari et al. 2000a, 2003, Sanders et al. 2007). Thus investigating how regional and local processes interact to affect community dynamics at fine spatial scale can help understanding what are the principal drivers of ant diversity. Whereas most ecological experiments are set in highly controlled and uniform setups (although see Arnan et al. 2007), I used natural variation in climatic conditions along an environmental gradient combined with a manipulative experiment to assess how these regional factors interact with local scale processes to shape leaf-litter ant communities. Results from this work show that both regional and local ecological processes are important in shaping ant community structure and regulating ant diversity.
Recently, two key studies regarding the role of dominant ants in shaping communities were published. The first study proposed a mechanism by which dominant species limit diversity (Parr et al. 2005), whereas the second one suggested a mechanism by which dominants might promote diversity (Adler et al. 2007). Parr et al. (2005) perceive dominant ants as a factor imposing a limit to the number of subordinate species that can coexist in a community. Alternatively, Adler et al. (2007) suggest that dominant ants are structuring agents of ant communities and that subordinate coexist with dominant by being better at exploiting resources. Ecological mechanisms possibly allowing behaviorally subordinate ants to coexist with dominants have been documented only in a few systems, and their generality remain to be tested. Behavioral tradeoffs and the humped-shape dominance-richness relationship seem to be context dependant, thus performing behavioral assays at different sites may help elucidating which factors drive these patterns. My work in Japan, Spain and southeastern US during summer 2008 was aimed at assessing the role of dominant ants in shaping ant community structure.
Novel molecular techniques allow ecologists to place their work in an evolutionary context. New phylogenetic approaches allow making solid inferences regarding the evolutionary relationships liking taxa to each other. Newly available information about the phylogenetic relatedness of sympatric taxa offers opportunities to take a deeper look at the fundamental mechanisms by which communities assemble and species coexist. Biological invasion also offer insights in the forces driving community assembly. Invasive ant species disassemble (Sanders et al. 2003) and might also re-organize native communities in non-random manner. By examining whether there is a phylogenetic signal in the way invasive ants alter the structure of native ant communities, one can get a closer look at mechanisms leading to community disassembly. Using community phylogenetics in the context of biological invasion might also reveal unexpected and more pervasive effects of invasive ants on native ant communities than what has thus far been documented.