Diversification of mowing regime increases arthropods diversity in species-poor cultural hay meadows

Abstract

Agricultural intensification reduces the biodiversity of European farmlands. Hay meadows represent an important farmland habitat, traditionally used to produce hay. With decreased demand for hay, the continuation of hay harvest is supported by Agri-environmental schemes across European Union. Modern hay harvest techniques differ from traditional manual harvest by removing the grass instantaneously over large land areas. To minimize adverse effects on meadow invertebrates, diversifying harvest operations is time and space is often recommended, but effects of such diversification are little studied. We compared the impact of uniform hay harvests with harvests executed in patchy manners, using four arthropod groups (butterflies, ground beetles, orthopterans and spiders) at productive, species-poor meadows in the Czech Republic. Butterflies, observed along transects, avoided uniformly cut units, preferring those cut as strips or blocks. In the three remaining groups, recorded using pitfall traps, a majority of species prevailed in traps located in uncut conditions. Synchronous mowing of large areas suppresses population sizes and diminishes the diversity of common arthropods. Besides of direct mortality and depletion of such resources as nectar or shelter, it synchronises sward regrowth, threatening also species requiring short-sward patches. Uniformly executed mowing contradicts the biodiversity conservation goal of Agri-environmental schemes. Diversifying the mowing operations via temporary fallows, or sequential mowing of land units, will improve the situation for common cultural meadows.

Resource use in two contrasting habitat types raises different challenges for the conservation of the dryad butterfly Minois dryas

“…Thus, it may be good practice to apply rotational grazing or mowing (Dolek and Geyer 1997;WallisDeVries et al 2002;Cremene et al 2005), since patches under a diverse mowing regime are preferred by butterflies and other insects (Cizek et al 2012). A single fragment should be mown every 2-3 years.…”

Moths and management of a grassland reserve: regular mowing and temporary abandonment support different species

“…However, as argued by Morris (2000), it does not suffice that management of small grassland reserves just mimics traditional land use, because in homogenised landscapes, existing reserves need to pack a maximum of the past biodiversity of wider landscapes. The current increasingly advocated practices such as rotational fallow (Schmidt et al 2008), or strip-mowing with postponed cuts (Grill et al 2008;Čížek et al 2012) represent methods of including temporary abandonment to reserve management techniques.…”

“…Some studies targeted entire landscapes, comparing management impacts on insects over large scales (Bergman et al 2004;Wickramasinghe et al 2004). They typically relied on a few model groups, such as butterflies (Öckinger & Smith 2006;Rundlöf et al 2008), or bumblebees (Haaland & Gyllin 2010), although multi-taxa comparisons also exist (Meek et al 2002;Roth et al 2008;Sjodin et al 2008;Čížek et al 2012). …”

Pluralism in grassland management promotes butterfly diversity in a large Central European conservation area

“…Overall, our results lend support to the hypothesis that a combination of different land-use and management options for grassland indeed provides a useful strategy to increase species diversity of butterflies and burnet moths at the landscape level. For hay harvest, earlier studies revealed that a diversification of mowing regimes may substantially contribute to biodiversity conservation (Cizek et al 2012). Our results indicate that the parallel maintenance of mown and grazed sites in the landscape increases beta-diversity.…”