Soil feedback does not explain mowing effects on vegetation structure in a semi-natural grassland

Maintain species-rich, semi-natural grassland

A replicated, controlled, randomized study of previously restored semi-natural grassland in central Finland (Ilmarinen & Mikola 2009) found that mowing affected woody plants, leguminous broadleaved plants (forbs) and bacterial-feeding nematodes (Nematoda), but not overall plant abundance or species diversity. Mowing significantly decreased cover of woody plants (mown: 2-10%; unmown: 10-45%) and increased cover of leguminous broadleaved plants (16-42% vs 5-18%), selfheal Prunella vulgaris, birdeye pearlwort Sagina procumbens and white clover Trifolium repens in 2004. Grasses and broadleaved plants and horsetails did not differ and there was no significant difference between annual and bi-annual mowing. Bacterial-feeding nematodes were more abundant in annually mown (9/g dry soil) compared to bi-annually mown (7/g) and unmown (4/g) plots in the upper, but not lower, part of the grassland. Fungal, root and omnivorous-feeding nematodes and pot worms (Enchytraeidae) were not affected by mowing. The three mowing treatments were allocated randomly to the 30 plots (1 x 1 m, 60 cm-wide buffer zones). Plants were sampled in June 2002-2004.