Disturbance effects on early succession of field margins along the shaded and unshaded side of a tree lane

Effects of light and disturbance on species diversity and vegetation succession were assessed during early succession of newly created sown and unsown field margin strips installed along the sunny and shady side of a tree lane. During succession, disturbance by farming operations was simulated by a single rotocultivation of the margin strip. Two years after the disturbance event, species richness was not significantly determined by light regime or disturbance level. However, shortly after the disturbance event, disturbance caused a temporary increase in species richness on the unshaded side due to introgression by annual species in created gaps. On the shaded side, species richness was significantly lower in disturbed plots. Disturbance caused a temporary increase in importance of spontaneous annuals, which were quickly replaced by perennial sown and unsown monocotyledons and to a lesser extent by perennial unsown dicotyledons. The importance of spontaneous species within functional groups increased, resulting in higher similarity between sown and unsown vegetation. (0 2005 Elsevier B.V. All rights reserved.