Evaluation of artificial habitats for saproxylic oak invertebrates: Effects of substrate, composition and distance from dispersal source

Abstract: Saproxylic species living in old hollow trees have low dispersal rate. Many of the species are threatened since their micro habitats are rare. To prevent some of these species from going extinct their habitats have to have the right management. In some areas artificial environment could be a solution. The aim of this study was to investigate if the insects that are dependent on tree cavities with wood mould would colonize an artificially created habitat: large wooden boxes filled with artificial wood mould placed on tree trunks. The boxes were filled with substrates like oak saw dust, oak leaves, dead hens, hen excrements, medicago (Medicago falcata flour) or potatoes. Over three years, 136 species and 10 380 specimens were caught in 47 boxes. The groups classified as specialists were in general statistically significant more often than groups classified as generalists. Dead hen was the substrate with the highest number of species, although differences were small. In conclusion, a large number of species, including red listed ones and saproxylic specialists used the boxes. A dead hen in the box gave some extra species and 1800 meters was too long for some of the species to disperse. Hence, the prospects for using artificial environments are good especially to reduce habitat availability gaps in time and space.