Plant species effects on soil macrofauna density in grassy arable fallows of different age

The density of soil macrofauna groups in nine grassy arable fallows of different age were investigated in a factorial design with the factors ‘plant species’ (legume: Medicago sativa, herb: Taraxacum officinale, grass: Bromus sterilis) and ‘age class’ (A1: 2–3/3–4, A2: 6–8/7–9, A3: 12–15/13–16 years in 2008/2009). Four plots were selected randomly at each fallow. In May 2008 and May 2009, within each plot five M. sativa, T. officinale and B. sterilis plants were extracted with their associated soil using steel cylinders. The material from each plant species was used for extraction of soil macrofauna and for determination of environmental parameters. The main results were (i) the density of the saprophagous macrofauna was significantly higher in B. sterilis than in M. sativa and T. officinale samples indicating that this group possibly benefited from the particularly high amount of fine roots in the B. sterilis samples; (ii) densities of Gastropoda and predatory beetles were highest in the 7–9 yr old fallows indicating that predators may have benefited from the increased availability of their prey in the medium stage of grassland succession; (iii) focusing on the results of the CCAs (2008, 2009), the water content had the strongest influence of the measured soil parameters on the structure of the soil macrofauna assemblages.