Influence of mowing measures on carabid beetle fauna (Coleoptera: Carabidae) in a post-agricultural area

Background and purpose: Some agricultural practices are considered to be useful tools in biodiversity conservation. Therefore, carabid beetles were collected on post-agricultural fallow land in Western Poland in order to study the impact of mowing treatment. Materials and Methods: Following a "before-after-control-impact" (BACI) study design over the period of two years (2013 - 2014), standard arrays of pitfall traps were installed on six study sites, of which three were treated by mowing at the beginning of July in the second year of study. The influence of this treatment was analysed statistically with respect to the most frequently collected species, selected ecological traits, as well as the mean individual biomass of the carabid assemblages (MIB). Additionally, Non-metric Multidimensional Scaling (NMDS) was carried out. Results: A total of 1995 individuals belonging to 40 species were collected, with species numbers ranging from 11 to 21 and numbers of individuals ranging from 76 to 278 in the samples. Although some species reacted significantly to the mowing treatment and numbers of individuals of forest species significantly decreased on the treatment sites, in general rather weak effects were observed as a result of the mowing measures. The weak effects of the mowing measures may be explained by the low cutting intensity (only once a year) and differences in environmental conditions between the years of study. Conclusions: The results of the study are assumed to be useful in the context of planning mowing measures in order to conserve biological diversity. Yet, the results also underline the importance of long-term studies.