PARENT SESSION
Poster Session 7: Grasslands
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Seed bank in dynamics of xerophilous vegetation in a Central European sandy region.

Papp, Maria^*,1, Matus, Gabor¹, Torok, Peter¹, ¹ Debrecen University, Debrecen, Hungary

ABSTRACT- We studied soil seed banks and dynamics in xerophilous vegetation of dry inland dunes at sandy region of North East Hungary. Seedling emergence method combined with sample concentration was applied. Seed bank samples originating from 90 permanent plots of 18 stands were analysed. Seminatural dry acidic grasslands (Festuco vaginatae-Corynephoretum), intact and degraded stands of sandy pastures (Potentillo-Festucetum pseudovinae), steppe meadows (Salvio-Festucetum rupicolae), differently aged plantations and spontaneously spreading stands of the invasive North American black locust (Robinia pseudoacacia) were sampled. Stratified seed bank sampling in the spring aspect was preceded with 5-12 years of vegetation survey in the spring, summer and autumn aspects. Species strategies were analysed using the long-term data on dynamics of aboveground vegetation as well as representation and vertical distribution of seeds in the soil. Over 200 taxa, representing ca. 9% of the Hungarian flora, were recorded the third of which had sufficient number of records (present in more than 3 stands) to be classified into seed bank types. Most species recorded in aboveground vegetation also possessed viable seed banks in the soil. Xerophyte annuals and short-lived perennials occurred in most seed bank samples and also had the highest seed densities. In contrast, seed bank formation of perennial grasses and sedges varied to a great extent among stands, depending on the reproductive performance of the population, suggesting at most short-term persistent seed banks. No persistent seed banks were, however, recorded at most of the wind-dispersed perennial forbs, in bulbous monocots, in some perennial grasses, suggesting transient or short-term persistent seed banks. This strategy also applies for a few annuals typical of open grasslands. Except for recently degraded stands, early successional pioneers with long-term persistent seeds tended to be confined to soil seed banks but were missing from the vegetation. The same holds for hygrophytes, the presence of which in the studied dry dunes can indicate frequent dispersal events, either by anemochory or zoochory, from neighbouring wetlands.

Key words: Psammophilous vegetation, Vegetation dynamics, Species strategies, Soil seed bank