Island Colonization of Carabidae: Neutrality or Habitat Choice?

Abstract

Carabidae of 15 island and two forested mainland sites from the largest archipelago in Poland, the Mazurian Lake Mamry, were sampled to infer whether island colonization can be linked to habitat heterogeneity and island isolation or whether a previously applied neutral model explains observed spatial distributions best. Kruskall-Wallis rank tests and regression analysis did not point to wing development (a proxy for dispersal ability), island isolation, and heterogeneity as significant factors that influence occupancy. Subsequent analysis of species co-occurrences and nestedness pointed to random pairwise species associations. Co-occurrence analysis of all species pairs found many fewer significantly non-random species pairs (at the 5% error benchmark) than expected by chance. These results do not point to habitat selection by ground beetles but rather favor the view that island colonization is a random process that is best modeled from a neutral perspective.

Keywords:

• habitat diversity
• isolation
• wing polymorphism
• island
• neutral model
• competition