Combining phylogenetic and ecological niche modeling approaches to determine distribution and historical biogeography of Black Hills mountain snails (Oreohelicidae)

Abstract

ABSTRACTWe aim to show how a combination of molecular systematics and ecological niche modelling approaches can be used to test historical biogeographical hypotheses for species of conservation concern. We focus on the land snail genus Oreohelix (Oreohelicidae), a group found throughout the Rocky Mountains. In addition to its larger distribution, a group of Oreohelix is also found in the Black Hills of Wyoming and South Dakota, an isolated, easternmost extension of the Rocky Mountains. We determine the number, distribution, and relationships of Black Hills Oreohelicids, which are a current conservation concern due to their fragmented distribution. We compared Black Hills groups to those in the main part of the Rockies to test historical biogeographical patterns that explain current diversity. We collected mtDNA data (COI and 12S sequences) from multiple populations of Oreohelix throughout the Black Hills and in adjacent populations in the Rocky Mountains to construct phylogenetic hypotheses. To determine whether favourable environmental conditions currently exist between the Black Hills and the north‐eastern Rocky Mountains, we used DesktopGARP to generate an ecological niche model for distinct lineages discovered in the molecular phylogenetic analysis. Results show that all Black Hills populations are likely Oreohelix cooperi and that little genetic differentiation exists within this clade. In addition, Black Hills groups are genetically similar or identical to populations found in the Judith Mountains and Bighorn Mountains (north‐eastern Rockies). Ecological niche models show that suitable environmental conditions may exist between eastern Rockies and Black Hills O. cooperi samples. Taken together, the phylogenetic and niche model data, along with the low vagility of the snails, support passive long‐distance dispersal as a likely explanation for current arrangement of biodiversity.