Invasive and socially parasitic ants are good bioindicators of habitat quality in Mediterranean forest remnants in northeast Spain

Abstract

We surveyed ants in 16 forest remnants in the Vallès lowlands north of Barcelona, Spain: eight with invasive exotic ants (IE = Linepithema humile and/or Lasius neglectus) present, seven with native parasitic ants (P = Lasius meridionalis, Lasius carniolicus, Plagiolepis xene, Chalepoxenus muellerianus, and/or Polyergus rufescens) present, and one remnant with both invasive exotic and parasitic ants present. Forest remnants with IE ants were smaller, more isolated, had greater perimeter/area, lower ant species density, and lower ant species richness than remnants with P ants. The community composition was also significantly different, with greater dissimilarity within remnants with alien, invasive species. The presence of some species is bio‐indicator of low disturbance, whereas others are indicative of high disturbance. Our findings underscore the value of different types of ants as bio‐indicators of fragmentation and habitat quality.

Colonization and coexistence of non‐native ants on a model Atlantic island

“…Habitat quality is often poorer in close proximity to settlements (Ahrends et al, 2010; Xiong et al, 2020) and on Ascension this manifested in dominance of invasive vegetation, mostly comprising Mexican thorn ( Prosopis juliflora ; Ascension Island Government, 2015). Invasive ants are known to establish more readily on barren and disturbed habitats (Bernal & Espadaler, 2013; Ramalingam & Dharma, 2022), and so restoring such habitat may create an ecological barrier to ant establishment outside of settlements. Such habitat restoration effort to meaningful buffer widths would be costly, but undoubtedly cheaper than the comparative cost of managing continual invasive ant colonization in the future.…”