Individual study: Restoration experiments (fertilizer addition, hay and sod removal) on meadows near Wageningen, Gelderlands, the Netherlands
Berendse F., Oomes M.J.M., Altena H.J. & Elberse W.T. (1992) Experiments on the restoration of species-rich meadows in the Netherlands. Biological Conservation, 62, 59-65
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Restore or create traditional water meadows
A trial from 1985 to 1990 on what was once a species-rich wet meadow at the Veenkampen, near Wageningen, the Netherlands (Berendse et al. 1992) found that topsoil removal increased the number of plant species on plots managed as hay meadows, and allowed rare sedge (Cyperaceae) species to establish. Three 15 x 25 m plots had topsoil removed to 5 cm depth. Each had a different water level, so they were not replicated. The number of plant species in these plots remained relatively stable or increased between 1987 and 1990 regardless of water level (dry plots increased from 21 to 28 species). The number of plant species was greater than in plots without soil removal. From 1988, carnation sedge Carex panicea and three other sedge species usually restricted to nature reserves in the region were found. Plots that were mown once or twice each year without soil removal (five replicates of four different mowing and hay removal treatments on 10 x 15 m plots) lost plant species. They had 18-20 species in 1987 and 14-17 in 1990. No fertilizer was applied during the experiment.
Raise water levels in ditches or grassland
A replicated trial from 1987 to 1989 on what was once a species-rich wet meadow at the Veenkampen, near Wageningen in the Netherlands (Berendse et al. 1992) found that areas with raised water levels lost plant species overall, but species favouring wet conditions increased. Cuckoo flower Cardamine pratensis, creeping buttercup Ranunculus repens, water foxtail Alopecurus geniculatus and creeping bent grass Agrostis stolonifera increased on wet and intermediately wet plots, but the total number of plant species fell from around 20 to around 15. Dry plots had 14-18 plant species throughout. The area was divided into three compartments. One had water levels 30-70 cm below the soil surface in summer and 5-40 cm below in winter, like the surrounding farmland. A wet and an intermediate compartment had embankments built and water added. In the wet compartment, summer water levels were 10-50 cm below the surface, and winter levels 0-20 cm below the surface. The intermediate compartment was in between wet and dry levels. Other experimental treatments were tested in these compartments. No fertilizer was applied during the experiment, and plots were mown for hay once or twice each year. Plants were monitored annually, in fifty 0.25m2 quadrats/plot.
Reduce chemical inputs in grassland management
Two long-term replicated trials near Wageningen in the Netherlands (Berendse et al. 1992) found that ceasing fertilizer inputs reduced the rate of plant species loss over 30 years, relative to conventional fertilizer application rate, but did not affect plant species loss over 17 years relative to a reduced rate of fertilizer application. The first experiment compared no fertilizer with 160 kg N/ha/year from 1958 to 1988, with two replicate 16 x 2.5 m plots of each treatment. Fertilized plots changed from 39 plant species to 10, while unfertilized plots had a slight but not significant drop in the number of species, from 33 to around 25. Plants were monitored annually, in fifty 0.25m2 quadrats in each plot. The second experiment compared no fertilizer with 50 kg N/ha/year, from 1972 to 1989, with four replicate 10 x 10 m plots for each treatment. The number of plant species steadily declined in both treatments from 20 in 1973 to 12 in 1989. All plots were mown twice a year, with hay removed