1. Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Högskoleringen 5 NO‐7491 Trondheim Norway
2. Dept of Biological Sciences, Univ. of Alaska Anchorage AK USA
3. Inst. of Geoecology and Geoinformation, Adam Mickiewicz Univ. Poznan Wielkopolskie Poland