Long-termed changes in ground beetle (Coleoptera: Carabidae) assemblages in a field treated by organic fertilizers

In 2001-2006, ground beetles were pitfall-trapped in a temperate lowland area of South Slovakia in an experimental field divided in five plots fertilized by four different doses of manure or biosludge (25 t stable manure ha(-1), 50 t biosludge ha(-1), 50 t stable manure ha(-1), 100 t biosludge ha(-1) and without fertilization). The field was subsequently sown by spring barley, sugar beat, maize, sun flower, sugar beat and maize. The ground beetle assemblage consisted of 31 species, but only five species predominated: Pseudoophonus rufipes representing 82.6% of individuals and five species (Poecilus cupreus, Carabus scheidleri, Calathus fuscipes, Trechus quadristriatus, Pterostichus melanarius, Anchomenus dorsalis, Dolichus halensis) representing together 14.5% of individuals. Pseudophonus rufipes represented 81.7% of dry biomass and three species (Carabus scheidleri, Poecilus cupreus Pterostichus melanarius) 15.9% of biomass. There was no significant influence of organic fertilizing on assemblage structure. During the investigation, the number of individuals and their biomass increased in all plots until 2003 and than dropped to the starting values. The culmination of 2003 was preceded by a warmer and more humid season in 2002. After a cold and dry season of 2003 abundance decreased approximately to starting values. Simultaneously, the local maxima and minima of occurrence of ground beetles in individual plots shifted independently on the doses of organic material. At the same time, number of occurring species slightly decreased. The observed changes obviously represent part of long-termed fluctuations in wider surroundings.