The effects of different mowing regimes on diversity of grasses in lowland meadows

Abstract

This study addresses the question of how changing the mowing regime influences the floristic composition and floristicdiversity of grasses in an experimental lowland meadow. The study location is Białowieża Forest, NE Poland. To achieve the aim we usedphytosociological data from long-term studies in Białowieża Forest on the course of secondary succession. The relationship betweenthe biodiversity of grasses and type of mowing was determined using statistical analysis. Changes in the dominance and frequencyof individual grass species have occurred during the last 28 years of observations. The analysis of floristic similarity demonstrated aturnover of species between the individual years of observation. Principal component analysis showed that the change in mowingmethod resulted in a change of the species composition, cover, and domination. However, differences in the intensity of disturbancelevel were rather small (one cut yearly by scythe, by sickle bar mower, and by trimmer), and changes in floristic composition werealso moderate in most years. During the initial years (1984–1990), Dactylis glomerata, Agrostis gigantea, and Anthoxanthum odoratumdominated. After 1990, Arrhenatherum elatius and Holcus lanatus spread and took over, with Trisetum flavescens joining them later.Between 2008 and 2012 the cover of Dactylis glomerata increased more than two times. The reasons for the floristic transformationswere changes in the management mode, e.g., the transition from mowing by scythe (medium disturbance) to mechanized mowing, firstby sickle bar mower (strong disturbance) and then by trimmer (weak disturbance).