OCCURRENCE OF RARE AND THREATENED INSECTS LIVING ON DECAYING POPULUS-TREMULA - A COMPARISON BETWEEN FINNISH AND RUSSIAN KARELIA

Beetles and flat bugs living on the decaying wood of aspen (mainly un r ar ) were collected during expeditions to Finnish and Russian Kareli a. Similar searching methods were used, and a comparable number of sit es and trees (about 120) were examined on both sides of the border. Th e fauna on aspen in Russian Karelia was considerably rich. A total of 21 and 5 rare species were found in Russian Karelia and Finnish Kareli a, respectively. Within about twenty working hours in Russ. Karelia we encountered two species considered extinct in Finland (Hylochares cru entatus and Cyllodes ater) and five considered endangered or vulnerabl e (Acritus minutus, Rhacopus attenuatus, Uleiota planata, Cucujus cinn aberinus and Aradus truncatus). We suggest that the high number of rar e species at the sites studied in Russian Karelia is attributable to t he different management history of the forests, particularly to the ab undance and continuity of large, dead aspens. Disturbance caused by lo gging and leaving the non-marketable trees has probably increased the diversity at some sites in Russ. Karelia. Aspens killed by notching wh ich are common in eastern Finland had a poor fauna.