Gábor Matus

Restoration prospects of abandoned species-rich sandy grassland in Hungary

Abstract Secondary succession and seed bank formation was studied in a formerly grazed, abandoned, eastern Hungarian sandy steppe-meadow (Pulsatillo-Festucetum). The vegetation was sampled at different elevations of a sand dune which became partly invaded by the tree Robinia pseudo-acacia ca. 10 yr ago. Pre-abandonment vegetation records were used as historic references. Though composition of the non-invaded grassland only changed moderately, dominance of tall grasses (Elymus hispidus, Poa angustifolia) increased significantly at the cost of annuals and low stature perennials. In the stand invaded by Robinia most grassland species were lost and replaced by nitrophytes. Vertical position influenced species abundance, but affected the composition only moderately. Fine-scale zonation of the vegetation also changed with time. Species richness of the above-ground vegetation and the seed density of soil samples at the lower elevation were slightly greater than at the higher sites. Seed banks of sensitive grassland specialists (e.g. Pulsatilla pratensis subsp. hungarica) disappeared during grass encroachment. Following extinction from above-ground vegetation, restoration must rely on dispersal from adjacent areas. In contrast, several annuals and perennials, which survived this degradation stage in the above-ground vegetation, possessed seed banks. Many of these species became extinct from the vegetation during the Robinia invasion but left viable persistent seeds. This fact is promising for restoration of the Potentillo-Festucetum sandy pasture. Competitive weedy species and sprouting Robinia can, however, limit seedling establishment. Nomenclature: Simon (2000) for taxa; Borhidi (2003) for syntaxa. Abbreviations: BIC = Bayesian Information Criterium, NMDS = Non-metric Multidimensional Scaling.

Restoration of the Cirsio dissecti-Molinietum in The Netherlands : Can we rely on soil seed banks?

Abstract Vegetation and soil seed banks of a threatened Atlantic fen meadow community were studied using recent phytosociological records and seedling emergence from soil samples. Similarly managed but differently degraded stands that suffered different levels of species impoverishment were compared. The actual vegetation was related to a set of phytosociological references representing the subassociations of the community. DCA positions of reference relevés from the different subassociations were overlapping, suggesting that in all references many common species occur. Recent records were positioned in-between the seed bank samples and the references. The soil seed banks of all stands were dominated by ordinary species. Most character species had at most sparse seed banks and no seedlings of locally extinct character species, mentioned in historic floristic records, were detected. In contrast species of pioneer and small-sedge communities as well as those of heathlands were abundant in the seed banks. Based on the vertical distribution of seeds in the soil layers most fen meadow species were classified into transient or short-term persistent seed bank types. We concluded that complete restoration of the Cirsio dissecti-Molinietum without reintroduction is only likely in stands that were degraded only a few years ago. On the other hand, the presence of viable seeds of Nanocyperion and Parvocaricetea species is promising for the restoration of these communities even after decades. Recreation of pioneer habitats by sod cutting will preserve these species. Nomenclature: van der Meijden (1996) for taxa; Schaminée et al. (1996) for syntaxa. Abbreviations: DCA = Detrended Correspondence Analysis; EXV = Eexterveld; ULE = Ule Krite; WYL = Wyldlannen; WTS = Wijnjeterperschar.

New measurements of thousand-seed weights of species in the Pannonian flora

For understanding local and regional seed dispersal and plant establishment processes and for considering the ecotypes and other forms of specific variability, hard data of locally or regionally measured traits are necessary. We provided newly measured seed weight data of 193 taxa, out of which 24 taxa had not been represented in the SID, LEDA or BiolFlor databases. Our new measurements and formerly published data of locally collected seed weight records together covers over 70% of the Pannonian flora. However, there is still a considerable lack in seed weight data of taxonomically problematic genera, even though they are represented in the Pannonian flora with a relatively high number of species and/or subspecies (e.g. Sorbus, Rosa, Rubus, Crataegus and Hieracium). Our regional database contains very sporadic data on aquatic plants (including also numerous invasive species reported from Hungary and neighbouring countries) and some rare weeds distributed in the southwestern part of the country. These fact...

The role of seed bank in the dynamics of understorey in an oak forest in Hungary

We studied the potential role of seed bank in the dynamics of the understorey in a turkey oak-sessile oak forest (Querceteum petraeae-cerris) in Hungary. We used long-term records of the herb layer (1973-2006) and the seed bank composition of 2006 to assess the role of seed bank in the regeneration of herb layer. The total cover of herb layer decreased from 22% (1973) to 6% (1988), and remained low (<10%) till 2006; coinciding with the increasing cover of secondary canopy dominated by Acer campestre. We found a low density seed bank (ca. 1300 seeds/m2). Altogether 33 species were germinated from the soil samples. A few generalist weed species composed the majority of seed bank. It was possible to assign a seed bank type for 19 species; 14 species out of 19 was long-term persistent. We found that the characteristic perennial forest herbs and grasses had only sparse seed bank. The Jaccard similarity between vegetation and seed bank was low (<30%). Our results suggest that the continuous establishment of forest herbs are not based on local persistent seed bank; it should be based on vegetative spreading and/or seed rain.