Are we conserving peripheral populations? An analysis of range structure of longhorn beetles (Coleoptera: Cerambycidae) in Finland

摘要

This paper characterises range structures of longhorn beetles (Coleoptera: Cerambycidae) occurring in Finland and classifies species as resource (host plant), substrate (specific host plant qualities) or climate limited. This information is then used to evaluate whether the IUCN red-list classification applied in Finland is directed towards peripheral European populations. Thirty (37%) longhorn beetle species are red-listed in Finland. Limited host plant distribution is adequate in explaining the red-list status for 43% of the red-listed species. All of these species are dependent on hardwood trees. Of the red-listed species that are dependent on widespread host plants, 30% have a limited extent of occurrence as well as a small area of occupancy in Finland. As these species are widespread outside Fennoscandia, their range in Finland is most likely limited by climate. Twenty per cent of the red-listed species have a wide extent of occurrence, albeit a small area of occupancy in Finland. As these species are dependent on widespread host plant species, but require specific substrate qualities (e.g. decaying, large diameter trunks), it is likely that their range is restricted by anthropogenic activities, mainly forestry and agriculture. The present study shows that the red-list classification in Finland is directed towards peripheral European populations. This study, however, did not address the conservation value of these populations.