Leaf-cutting ants proliferate in the Amazon: an expected response to forest edge?

Abstract

Habitat fragmentation is gradually altering tropical forests all around the globe (Wright 2005), as human populations convert large blocks of pristine forest habitats into permanently fragmented or human-modified landscapes (Tabarelli et al. 2004). Fragmentation processes apparently create opportunities for small sets of species, which proliferate across modified landscapes, while others are driven to extinction or remain as minimal populations (Tabarelli et al. 2010). This ‘winners vs. losers paradigm’ (sensu McKinney & Lockwood 1999) probably describes one of the most conspicuous rearrangements of tropical biotas in response to human disturbances (in addition to biomass collapse), with unanticipated consequences for ecosystem functioning and long-term biodiversity persistence (Lôbo et al. 2011). Despite such appeal, the ecological identity of proliferating organisms and the mechanisms underlying their high abundance levels remains poorly appreciated.