1. Department of Biology, Graduate School of Science Kobe University Kobe Japan
2. Tomakomai Experimental Forest, Field Science Center for Northern Biosphere Hokkaido University Tomakomai Japan
3. Uryu Experimental Forest, Field Science Center for Northern Biosphere Hokkaido University Horokanai Japan
4. Tomakomai Experimental Forest, Japan Wildlife Research Center Hokkaido University Tomakomai Japan