Bird Communities and Vegetation on Swedish Wet Meadows Importance of Management Regimes and Landscape Composition

Gustafson, T., 2006. Bird communities and vegetation on Swedish wet meadows – importance of management regimes and landscape composition. Doctor's dissertation. Wet meadows in Sweden currently depend on management by grazing to maintain habitats for various breeding and migrating birds. However, due to ceased cattle farming management by mowing could be an option for restoration and conservation of wet meadows. The general aim of this thesis is to analyse effects of different management regimes (mowing and grazing), landscape composition and flooding on inland wet meadow bird fauna and flora. Five wet meadow areas in southern Sweden were used for a four-year survey of breeding birds and environmental variables. Habitat openness was the most important factor for bird community composition. Species preferring open meadows decreased strongly in abundance at small amounts of forest, suggesting that clearing of woodlands could be important. The bird community was also strongly related to the amount of flooding. Effects of management were weaker, but several species showed positive associations with swards of intermediate height (5-30 cm), which are correlated to mowing with late season grazing. In addition, measures for restoring water table variation also need to be considered. Conservation of species dependent on continuous management (yearly grazing, mowing and late season grazing) and short swards should be targeted to large open meadows. Corncrakes preferred unmanaged meadows with tall vegetation, suggesting that mowing at intervals of a few years could be appropriate. Yellow Wagtails are likely to have higher breeding success in mowed than in grazed sites due to lack of nest destruction by livestock. The main gradients affecting distribution of vascular plants correlated to soil fertility and moist. Bird species associated with weak or no management correlated positively to nutrient levels, soil reaction, sward height and litter depth. In contrast, the assembly of bird species associated with continuous management, showed fewer associations to the sward variables, although their abundance was positively associated with abundance of forbs. Different mowing regimes may be a useful tool for management of meadow sward heterogeneity.