Spatial Pattern and Temporal Dynamics of Bryophyte Assemblages in Saline Grassland

Dynamics of bryophyte assemblages of saline grassland were studied in Hungary. A survey was carried out in two permanent plots by annual sampling of 0.25-m 2 quadrats over a 9-year period. The study investigated: i) the extent of spatial and temporal dependence of the assemblages and individual species; ii) the turnover of individual species and its relationship to life-strategy types and iii) the effect of annual weather conditions on species performance. One of the plots showed succession; the frequency of some perennial species increased, while that of some short-lived species decreased; this process was independent of local weather conditions. The other plot showed a non-directional fluctuation, which was partly related to precipitation in winter and early spring. The spatial and temporal dependence of this assemblage was low; many short-lived species had a high turnover in the studied community. In stable periods, neutral dynamic processes characterize the bryophyte assemblages of the studied saline grassland and the occurrences of species were more or less independent in space and time. Short-lived species showed high fluctuations and were probably influenced by weather conditions or other factors. However, the frequency of perennial species, which were influenced by local conditions, could directionally change displacing the short-lived ones during succession. The relationships between turnover and life-strategy types were weak, both the group of colonist and shuttle species were dynamically heterogeneous. Longer observations are needed for a clearer exploration of the relationships between vegetation changes and weather conditions.