The implications of seed rain and seed bank patterns for plant succession at the edges of abandoned fields in Mediterranean landscapes

Abstract

24Some environmental variables and above-ground vegetation, seed rain, ant-borne seeds and 25 seed banks were studied on three abandoned fields, at the margins between these fields and a 26 remnant patch of a native steppe vegetation of a high value for nature and species 27 conservation. While the fields were the same size, were adjacent to the same patch of 28 remnant steppe and were cultivated with the same crop, site-specific environmental variables 29 contributed to 23% of the vegetation patterns; each site was characterised by its unique 30 historical trajectory and thus, by a particular set of species. Distance from boundaries 31 contributed to 10% of the vegetation patterns. Species characterising the surrounding steppe 32were found close to boundaries; species characterising abandoned fields were found further 33 away. Winter seed banks and summer deep seed bank did not contribute much to either effect 34 and were characterised by species dating back from past cultivation. Conversely, summer 35 surface seed bank greatly contributed to (83%) the differences in species composition 36 between the three fields. Seed rain contributed to differences in species composition between 37 fields (91%) and distance (76%). Ant-borne seeds largely contributed to the differences 38 between fields (87%).

Recovery of soil and vegetation in semi-arid Australian old fields

“…Recovery from cultivation is commonly limited by seed availability (e.g. Buisson et al, 2006;Standish et al, 2007) and there is some evidence that perennial forbs may be seed limited in this region (Wong et al, 2007). Furthermore, although old fields converged towards the species composition of adjacent uncultivated grasslands, they did not all converge on a single target community.…”

Soil seed bank, fire season, and temporal patterns of germination in a seeder-dominated Mediterranean shrubland

“…Some species (e.g., Cistus ladanifer) disperse from summer to spring of the next year; others (e.g., Rosmarinus officinalis) start dispersing in spring and proceed until early summer (Moreno and Cruz 2000;Bastida and Talavera 2002;Clemente et al 2007). Data on temporal patterns of seed dispersal of herbaceous species in shrublands are sparse (Buisson et al 2006), but studies in Mediterranean grasslands indicate that dispersal occurs mainly in summer, with little variability among species (Espigares and Peco 1993;Ortega et al 1997).…”

Seed Rain of Restored and Natural Prairie Wetlands

“…Evaluating propagule availability requires estimating seed rain, a process that has been well studied in forests (e.g., Au et al 2006;del Castillo and Ríos 2008), grasslands (e.g., Buisson et al 2006;DiVittorio et al 2007), and riverine and coastal wetlands (e.g., Leck and Simpson 1994;Rand 2000;Crain et al 2008) but has been rarely studied in isolated wetlands like those in the prairie pothole region. Wetland seed rain studies indicate that many plant species are seed limited because of factors like limited dispersal abilities (e.g., Rand 2000; Barbosa and Pizo 2006).…”