Forest in Sicily

The Sicilian forestal landscape is part of an agro-forestal environment where wood stations, often spatially organized on grazing, alternate to scrublands and cultivated areas. In Roman times, the island\u2019s forest surface amounted to about one million hectares, but the deforestation practices carried out to give room to agriculture, along the centuries, reduced this surface to about a third. Forests are still well preserved on mountains and above all on the Sicani, Madonie, and Nebrodi ranges and on Mt. Etna. On the remaining territory, the forest landscape is quite irregular and characterized by small stations within agricultural and grazing territories. On the basis of the last Regional Forests Inventory, today the total forestal surface amounts to 512 thousand hectares, but only 274 thousand are real woods; the remaining surface is made of maquis, shrublands, and grounds evolving into woods. The presence of so many areas evolving into woods is due to the fact that, on these areas, cultivation, and above all grazing, have been abandoned. Sicilian forests have been classified into 14 forest categories (9 of broadleaf trees, 3 of conifers, 2 of maquis and shrublands), subdivided into 58 forest Types; these forest categories have been defined on a physiognomic basis according to the prevailing species and then subdivided into types according to the vegetation dynamics

Data from: Dispersal ability and habitat requirements determine landscape-level genetic patterns in desert aquatic insects

Species occupying the same geographic range can exhibit remarkably different population structures across the landscape, ranging from highly diversified to panmictic. Given limitations on collecting population-level data for large numbers of species, ecologists seek to identify proximate organismal traits—such as dispersal ability, habitat preference and life history—that are strong predictors of realized population structure. We examined how dispersal ability and habitat structure affect the regional balance of gene flow and genetic drift within three aquatic insects that represent the range of dispersal abilities and habitat requirements observed in desert stream insect communities. For each species, we tested for linear relationships between genetic distances and geographic distances using Euclidean and landscape-based metrics of resistance. We found that the moderate-disperser Mesocapnia arizonensis (Plecoptera: Capniidae) has a strong isolation-by-distance pattern, suggesting migration–drift equilibrium. By contrast, population structure in the flightless Abedus herberti (Hemiptera: Belostomatidae) is influenced by genetic drift, while gene flow is the dominant force in the strong-flying Boreonectes aequinoctialis (Coleoptera: Dytiscidae). The best-fitting landscape model for M. arizonensis was based on Euclidean distance. Analyses also identified a strong spatial scale-dependence, where landscape genetic methods only performed well for species that were intermediate in dispersal ability. Our results highlight the fact that when either gene flow or genetic drift dominates in shaping population structure, no detectable relationship between genetic and geographic distances is expected at certain spatial scales. This study provides insight into how gene flow and drift interact at the regional scale for these insects as well as the organisms that share similar habitats and dispersal abilities

Microsatellite genotype data for 3 aquatic insect species

The data set includes 3 text files, one for each of three aquatic insect species. Each is a GENEPOP input file. Loci are microsatellite markers. The order of the populations in each file is the same as in the manuscript

Stats in R_MLPE_VanStrien_STAE

R scripts for running MLPE on Boreonectes aequinoctialis msat data