Effects of agricultural practices on spatial dispersal patterns of permanent grassland species

摘要

The effects of agricultural practices on floristic composition of grasslands are well known but few studies have investigated these effects on plant spatial patterns involved in the maintenance of plant diversity. In order to identify major processescontrolling dispersal patterns of four grassland species, which represented different dispersal methods (anemo-chorous, barochorous and zoochorous), spatial analysis (4TLQV and Wavelet) was used and adapted to grid sampling. The quadrat variances were plotted against block size, and the peaks of graphs interpreted as the scale of the mapped phenomena. The results highlighted the general impacts of mowing in relation to the dispersal characteristics of different plant species. An effect of mowing on spatial patterns from functional traits connected to dispersal was shown by spatial analysis, e.g. dispersal distances of baroehorous species such as Ranunculus bulbosus were enhanced by mowing and grazing and reached a maximum of 1 m, whereas a zoochorous grass (Festuca arundinacea), which has the theoretical capacity to produce expansive lateral spread up to 1 m, was limited in its expansion by cutting and grazing to 0.30 m. The study also showed that disturbance can play an important role in dispersal and the spatial structure of grassland species.