Influence of grasslands management on diversity of the diurnal butterflies of Vlkolínec Village (Central Slovakia)
During 2011–2012, the research of diurnal butterfly communities in ten study sites under different management measures in the vicinity of the village of Vlkolínec was performed. The village of Vlkolínec is located in the northern part of Central Slovakia in the buffer zone of the Veľká Fatra National Park. Abandoned meadows and fallows are prevailing in the study area, thus, traditional management is gradually disappearing, which results in ecosystems changing and decline of biodiversity. Adults were recorded by the modified transect method (Erhardt, 1985) in the following types of habitats: extensive and intensive pasture, old fallow lands of various successional stages and fallow lands exploited by mulching. Shannon-Weaver index of diversity (H) and equitability (e) were used for estimation of the quantitative and qualitative structure of the butterfly assemblages. To study the impact of anthropogenic factor (mulching, pasture and abandonment) on the butterfly diversity multivariable statistical methods (CANOCO 4.5 software) were used. Summarily, 2314 individuals of 63 species were sampled. The most of species were classified into the Nymphalidae family. During two-year research the highest values for number of species and diversity indices were recorded in the grasslands of late successional stages and extensive pastures. The highest number of grassland indicators and protected species, such as Limenitis populi, Melitaea aurelia, M. diamina, Polyommatus bellargus, P. daphnis, P. thersites, Thymelicus acteon and two European important species Phengaris arion and P. rebeli, were recorded in those habitats. Intensification of landscape leads to sterile grasslands, which are the unsuitable habitats for butterflies, and the main reason of negative effect of intensive grazing is a change of vegetation structure, which is the factor most of stenotopic butterflies are negatively correlated with. Extensive management has a positive impact on the assemblages of daily butterflies and landscape biodiversity, as the RDA analysis has shown for some of the localities studied where we found positive correlation of many specialized and indicator species (such as Pyrgus malvae, Polyommatus dorylas, P. thersites, P. bellargus, Melitaea aurelia). The RDA analysis has also indicated positive impact of succession on the butterfly diversity. Our results prove that intensive management, such as long-term mulching and intensive pasture, has negative impact on the abundance and structure of butterfly assemblages. Extensive pastures and old fallow lands represent important habitats of the country, however, their importance is often overlooked.