Monitoring of butterflies is most often only directed towards the grassland fauna.
Species associated with other vegetation types, as well as the impact of the surrounding landscape, often become neglected. The aim with this study was, in contrast, to perform a novel landscape-based monitoring method for butterflies in diverse vegetation types and more specifically (i) evaluate the impact of environmental variables on butterfly abundance, (ii) compare the distribution of butterflies in different vegetation types and (iii) analyse and improve the monitoring method. Eight randomly placed study sites (750 m x 750 m) located in south eastern Sweden were used. The vegetation composition inside the squares had been assessed using aerial photos. Tree cover had largest impact on butterfly abundance with a negative linear relationship between abundance and increasing tree cover. Clear-cuts were the vegetation type harbouring the overall highest abundance and diversity of butterflies. In semi-natural grasslands, where the nationally-based monitoring of butterflies in Sweden currently is being performed, only 42% of the species were found, indicating a bias directed towards only a part of the species pool.
The novel kind of monitoring presented here, using a landscape context, can, if performed regularly, increase our knowledge of how structural changes at landscape level affect butterflies and thereby improve the conservation efforts.
Keywords: conservation, semi-natural grasslands, landscape perspective, Lepidoptera, rarefaction, vegetation type.
2007. , 25 p.