Low seed pressure and competition from resident vegetation restricts dry grassland specialists to edges of abandoned fields Jana Knappová a, b, *, Zuzana Münzbergová a, b a Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 128 01 Prague, Czech Republic b Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, 252 43 Pru  honice, Czech Republic A R T I C L E I N F O Article history: Received 4 June 2014 Received in revised form 3 November 2014 Accepted 5 November 2014 Available online xxx Keywords: Dispersal traits Distribution Fallow land Habitat requirements Species richness Secondary succession A B S T R A C T The occurrence of 66 dry-grassland species was compared between the edges and the interiors of 48 abandoned fields in northern Bohemia, Czech Republic, Europe. More species occurred at the edges than in the interiors. The proximity of the source grassland had a positive effect on species richness at the edges but not in the interiors. Soil characteristics did not differ between the edges and the interiors, but aboveground biomass was significantly lower at the edges, suggesting that edges have more open vegetation and provide more microsites suitable for colonisation. Neither dispersal traits nor habitat requirements were significantly associated with species that were more narrowly restricted to the edges of fields. However, the species that occurred more often at the edges than in the interiors were those that were infrequent in dry grasslands within the study area. These species responded positively to the grassland neighbourhood, they had a narrower niche, lower specific leaf area, a shorter persistence in the seed bank and a later initiation of flowering. The results of the study indicate that low microsite availability, together with low seed pressure, is most limiting for these specialised and competitively inferior species. For this reason, they are much more restricted to dry grasslands, and their conservation relies primarily on proper management of their current habitats. The suitability of abandoned fields for grassland specialists could be enhanced by disturbance that would create colonisation microsites, and successful recruitment of grassland species can be supported by seed additions. ã 2014 Published by Elsevier B.V. 1. Introduction Abandoned fields provide an interesting study system for testing ecological theories. Additionally, they represent an impor- tant challenge for the practice of ecological restoration (Cramer et al., 2008). Fields in regions with a drier climate and nutrient- poor or shallow soils remain open and almost treeless during long periods after abandonment (Osbornová et al., 1990; Jongepierová et al., 2004; Ruprecht, 2006). Therefore, abandoned fields can be viewed as potential habitats for species from grasslands (Walker et al., 2004,b; Öster et al., 2009a,b; Knappová et al., 2012). Grasslands are among the valuable and species-rich habitats that are threatened by ongoing land use changes (Münzbergová, 2004; Pärtel et al., 2005; Chýlová and Münzbergová, 2008). The species richness of grasslands relies to a large extent on a suitable management regime, usually mowing or grazing, that prevents more competitive species from achieving dominance (Pärtel et al., 2005). Under certain circumstances, e.g., if the seed source of the target species is nearby and the seed bank of the ruderal species is missing, field succession might lead to grasslands of high conservation value with only minimum human intervention or with no human intervention at all (Jongepierová et al., 2004; Ruprecht, 2006). In most cases, however, the colonisation of abandoned fields by desirable (e.g., grassland) species is con- strained by both habitat conditions and seed availability (Buisson et al., 2006; Öster et al., 2009b; Knappová et al., 2012), and successful succession towards a grassland requires regular management or the assisted transfer of plant material (Pywell et al., 2002). The aim of this study was to explore whether abandoned fields in northern Bohemia, Czech Republic, central Europe can be considered suitable habitats for dry grassland plant species and to identify the main limiting factors for the successful spontaneous colonisation of these fields. Habitat suitability can be most directly assessed by seed addition experiments (Münzbergová and Herben, 2005; Öster et al., 2009b), but they are hardly applicable routinely on a large scale due to their high time and work demands. Moreover, the results can be strongly dependent on the amount of seeds added * Corresponding author. Tel.: +420 271 015 401; fax: +420 271 015 105. E-mail address: jana.knappova@ibot.cas.cz (J. Knappová). http://dx.doi.org/10.1016/j.agee.2014.11.008 0167-8809/ ã 2014 Published by Elsevier B.V. Agriculture, Ecosystems and Environment 200 (2015) 200–207 Contents lists available at ScienceDirect Agriculture, Ecosystems and Environment journa l homepage : www.e lsevier.com/loca te/agee