Timing of grazing and plant reproduction in semi-natural grasslands

Early and intense grazing of semi-natural grasslands replacing traditional mowing and late grazing has been identified as a threat to grassland biodiversity. We compared fruit production, fruit set attributes (e.g. plant size or phenology of reproduction), and differences in potentially negative effects (accumulation of ungrazed vegetation) in continuous grazing from May through September, with an experimental management regime, grazing from mid-July, within two different grasslands in Sweden. Vegetation and reproductive parts were monitored in plots at five to eight occasions over the season. The delayed onset of grazing enhanced fruit production of grassland plants up to four times. Among species, phenology of reproduction appeared to be the most important plant trait explaining differences in reproduction between management regimes. No differences in vegetation height or proportion of grazed shoots were found by the end of the season. The results suggest that early reproduction may function as an escape from damage under both continuous and late grazing, but that the functionality of this adaptation is limited under intense and early disturbance. Further, an increased use of traditional management methods may have positive effects on biodiversity of semi-natural grasslands.