engleski

Carabid beetle diversity and mean individual biomass in beech forests of various ages

Carabid beetle diversity and mean individual biomass (MIB) were analysed in three diff erent successional stages of beech tree stands (60, 80 and 150 years old). Carabid beetles were captured using pitfall traps placed at nine sites (three per age class) in the Papuk Mountains of East Croatia during 2008. A cluster analysis identifi ed three groupings that corresponded to the beech age classes. MIB valu es increased with stand age, ranging from 255 in 60-year-old stand to 537 in the oldest forests. Th e younger stands (60 and 80 years old) showed higher species richness and diversity values than the 150-year-old stand. With respect to species composition, large species such as Carabus scheidleri and Carabus coriaceus were dominant only in the oldest forests. Furthermore, species that overwinter in the larval stage were more abundant in the oldest forests (45% of the total number of individuals from the 150-year-old stand) than in the younger ones (20% of individuals from 60-year-old, and 22% of individuals from 80-year-old stands). Our results showed that the analyses of species composition and life history traits are valuable for estimating the conservation values of older forests. Although the investigated sites form part of a continuous forested area and are only a couple of kilometres apart, MIB values detect signifi cant diff erences associated with forest age and can be a useful tool in evaluating the degree to which a forest refl ects a natural state.

carabid beetles; MIB; over-wintering stages; beech forests succession; Nature Park

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