Ecogeographic patterns in a mainland-island system in Northern Europe as inferred from the rove beetles (Coleoptera: Staphylinidae) on Laeso island

Aslak K Hansen,David B Byriel,Sebastian Kepfer-Rojas,Mathias J Justesen,Alexey Solodovnikov,Jan Pedersen

doi:10.14411/eje.2018.025

Abstract

Rove beetles (Staphylinidae) are used to explore the forces that shaped the terrestrial fauna on Laeso, a young ca. 3000 year old Danish oceanic island located in the Kattegat strait between mainland Denmark and Sweden. We compile a detailed list of species of rove beetles for Laeso (328 species) and the surrounding Danish and Swedish regions (altogether 1075 species), which includes a standardized inventory of their body sizes, and the habitat and microhabitat preference of each species. The composition of the fauna on Laeso and adjacent mainland regions points to North-Eastern Jutland as the main source of the rove beetles on Laeso. Although large beetles are more active and likely to disperse than small beetles, there is no bias towards large species on the island indicating that the sea separating Laeso from the mainland has not been a barrier for rove beetle dispersal. The statistical analysis of the habitat and microhabitat preferences of the species of the entire system studied has shown that Laeso, compared to the mainland areas, is distinctly more dominated by ecological generalists, especially by species adapted to ephemeral, temporary humid microhabitats. Presumably, the mosaic of mostly dry open habitats available on Laeso filters for species, that are able to populate these suboptimal habitats via patches of humid but ephemeral microhabitats. A comprehensive eco-faunistic dataset for the Staphylinidae compiled for this study is the first modern account of the rove beetle fauna on the Danish island of Laeso.

Highlights

In this paper we aim to capture and measure patterns that give insights into the forces determining insect faunas and communities in a given area or a habitat
Rove beetles (Staphylinidae) are used to explore the forces that shaped the terrestrial fauna on Læsø, a young ca. 3000 year old Danish oceanic island located in the Kattegat strait between mainland Denmark and Sweden
Large beetles are more active and likely to disperse than small beetles, there is no bias towards large species on the island indicating that the sea separating Læsø from the mainland has not been a barrier for rove beetle dispersal

Summary

Introduction

In this paper we aim to capture and measure patterns that give insights into the forces determining insect faunas and communities in a given area or a habitat Understanding these driving forces, which include the capacity of insect species to disperse and establish in new geographic areas and habitats, are basic for studies on ecology, evolutionary biology or biogeography, because insects are a mega-diverse group and dominate modern biotas in terms of the number of species, abundance and their ecological effect. Well-known local insect faunas with fine presence/ absence data and an abundance of bionomic records for a large number of species occurring in a limited area provide simple models for studying ecogeographic patterns that help understand these relationships. It provides ecological information on thousands of species distributed across diverse landscapes on the mainland and many islands

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