Ground beetle assemblages (Coleoptera, Carabidae) in the third year of regeneration after a hurricane in the Puszcza Piska pine forests

In 2002, pine forests in Pisz Forest District (north-eastern Poland) were disturbed by a hurricane. Since then a survey on ground beetle (Coleoptera: Carabidae) assemblages inhabiting the damaged stands has been carried out. This article presents the results of the third year of this study. The carabid beetle fauna of damaged stands was compared with that of non-damaged stands in the Maskulinskie Forest District. In both disturbed and control stands, 15 plots in five different age classes were distinguished and investigated (3 plots in each age class): class I (20-40 years old), class II (40-50 years old), class III (50-60 years old), class IV (60-70 years old) and class V (above 70 years old). Beetles were sampled using modified pitfall traps. The soil CO2 efflux rate and C/N ratio of soil were also measured. A total of 5115 carabid individuals representing 38 species were recorded. After the hurricane, Carabidae assemblages markedly declined in abundance, although species richness was significantly higher in damaged stands compared to control stands (32 species and 26 species respectively). Both Ward's cluster analysis and CCA analysis clearly distinguished between carabid assemblages inhabiting disturbed stands with non-disturbed ones. Windthrow considerably reduced the proportion of forest, European and autumn breeding species fauna in carabid assemblages. A marked decline in abundance of hygrophilous species in favour of xerophilous ones was also observed. Amara and Harpalus species responded positively to disturbance increasing in abundance and richness in stand openings. According to the SPC (Sum of Progressive Characteristics) index reduction in Pisz Forest District, it might be concluded that the regeneration of carabid beetle assemblages in stands damaged by the hurricane has not started yet.