We tested the hypothesis that sympatry among closely related species is possible only in the absence of interspecific competition. The hypothesis was tested on a clade of subterranean amphipods, genus Niphargus, distributed in the Dinaric Karst, Western Balkan, Europe, by employing phylogenetic reconstructions; species delimitation; modelling competition using phylogeny and species distributions and reconstruction of historical dispersal. The results show that the clade comprises six species, which classify into two ecomorphs. Species of the same ecomorph are parapatric or allopatric, whereas species belonging to different ecomorphs overlap their ranges. The phylo-spatial reconstructions suggest that the shift from allopatry to sympatry is associated with relaxation of competitive interactions. The overall conclusion is that interspecific competition presumably controls evolutionary and ecological dynamics in subterranean environments in a similar way as in more familiar surface environments.
COBISS.SI-ID: 4969039