Permanent plot research in wet meadows and cutting experiment

Change season/timing of cutting/mowing: freshwater marshes

A replicated, randomized, paired, controlled study in 1983–1986 in two wet meadows in Switzerland (Buttler 1992) reported that summer and winter mowing had similar effects on overall plant community composition and structure, but different effects on some individual plant species. Statistical significance was not assessed. Over 3–4 years, plots mown in summer and winter experienced similar changes in overall plant community composition (partial data reported as a graphical analysis). Both mowing regimes were associated with a significant increase in the proportion of vegetation in lower layers. This was true for vegetation overall, and the dominant species in each community (partial data reported, as number of times survey pins touched living vegetation). Some individual species responded differently to each mowing regime. For example, common reed Phragmites communis developed more, thinner shoots and lower above-ground biomass over four years of summer mowing, but developed fewer, thicker shoots and greater above-ground biomass over three years of winter mowing (see original paper for partial data). Methods: Two pairs of plots (each 121–169 m²) were established in two historically mown, but abandoned, lakeside wet meadows. In each pair, one random plot was mown in winter (from early 1983) and one random plot was mown in late summer (from 1983). Cuttings were removed. Vegetation was surveyed each summer 1983–1986 (before mowing, where applicable).

(Summarised by: Nigel Taylor)

Change season/timing of vegetation harvest: freshwater marshes

A replicated, randomized, paired, controlled study in 1983–1986 in two wet meadows in Switzerland (Buttler 1992) reported that summer and winter harvesting had similar effects on overall plant community composition and structure, but different effects on some individual plant species. Statistical significance was not assessed. Over 3–4 years, plots harvested in summer and winter experienced similar changes in overall plant community composition (partial data reported as a graphical analysis). Both harvest regimes were associated with a significant increase in the proportion of vegetation in lower layers. This was true for vegetation overall, and the dominant species in each community (partial data reported, as number of times survey pins touched living vegetation). Some individual species responded differently to each harvest regime. For example, common reed Phragmites communis developed more, thinner shoots and lower above-ground biomass over four years of summer harvest, but developed fewer, thicker shoots and greater above-ground biomass over three years of winter harvest (see original paper for partial data). Methods: Two pairs of plots (each 121–169 m²) were established in two historically mown, but abandoned, lakeside wet meadows. In each pair, one random plot was mown in winter (from early 1983) and one random plot was mown in late summer (from 1983). Cuttings were removed. Vegetation was surveyed each summer 1983–1986 (before harvest, where applicable).

(Summarised by: Nigel Taylor)

Restore or create traditional water meadows

A replicated, controlled, randomized study of two wet meadows over four years in Switzerland (Buttler 1992) found that overall winter and summer (August) cuts had positive effects on plant species densities in terms of individuals, leaves, shoots and flowers. However individual species were affected differently by cutting regime. For example, an annual winter cut caused an increase in the number of flowers for common reed Phragmites communis (now P. australis), whilst a summer cut reduced them. Some drier vegetation communities were damaged when cut in summer, whereas wetter communities were more resilient to summer mowing. In general, annual winter cuts tended to improve the vitality of vascular plants (in terms of increased number of individuals, flowering and biomass). Plant vitality was lowest in uncut plots and intermediate with an annual summer cut and winter cut every three years. Vegetation structure differed with treatments (hay removed) and uncut controls. The meadows had been abandoned for many years and treatments were applied in three blocks with three replicates. Vegetation was sampled in July-August within 11 x 11 m and 13 x 13 m permanent plots from 1983 to 1986.

Cut/mow herbaceous plants to maintain or restore disturbance: freshwater marshes

A replicated, randomized, paired, controlled study in 1983–1986 in two wet meadows in Switzerland (Buttler 1992) reported that resuming annual mowing affected plant community composition and shifted the vegetation cover into lower layers. Statistical significance was not assessed. Within each of the two studied community types, the overall plant community composition became less similar in mown and unmown plots over 3–4 years (partial data reported as a graphical analysis). Meanwhile, mown plots experienced a shift in vegetation cover towards lower layers, whilst vegetation cover in unmown plots shifted towards the upper layers. This was true for vegetation overall, and for the dominant species in each community (partial data reported, as number of times survey pins touched living vegetation). These community and structural responses were similar whether cutting was done in summer or winter. However, responses of other individual species (e.g. density, shoot diameter and biomass of common reed Phragmites australis) differed between community types and mowing seasons (see Action: Change season/timing of cutting/mowing and original paper). Methods: Three sets of three plots (each 121–169 m²) were established in two historically mown lakeside wet meadows, that had been abandoned for “many years”. One random plot/set received each treatment: winter mowing (from early 1983), late summer mowing (from 1983) or no mowing. Cuttings were removed. Vegetation was surveyed each summer 1983–1986 (before annual mowing, where applicable).

(Summarised by: Nigel Taylor)