In this work, we aimed to test whether taxonomic diversity and functional diversity and
the values of functional traits of the weed seed bank varied across the field, from margins to the
core, and between fields embedded in distinct landscape structures. We sampled the seed bank of 47
conventionally managed cereal fields from two Mediterranean regions in Spain. In each field, three
positions were selected: Margin, edge and core, and soil properties were measured for each position.
Landscape structure was quantified for each field as the percentage of arable land in the surrounding
1 km radius circular sector. Seed bank diversity was characterized at the taxonomic (species richness,
exponential Shannon index, and evenness) and functional levels (Rao’s quadratic entropy index and
four corner analysis). For functional diversity, eight functional traits related to the whole plant life
cycle were considered. Results showed a slight response of increasing taxonomic diversity from the
core of the fields to the margins. Functional diversity was extremely low, indicating high similarity
among species in terms of functional traits. Species in the seed bank were mostly therophytes, shorter
than the crop plants, small seeded, flowering between the herbicide application of late winter and
crop harvest, and showed seed dispersal by gravity or wind. This trait syndrome allows persistence
in intensively managed arable lands. The similarity between fields in terms of functional diversity of
the seed bank and in species traits may suggest that the intensity of management practices was similar
across the fields. Moreover, it emphasizes that an increase in landscape heterogeneity, if based on
other intensively managed cropping systems, may not be suffcient to augment functional diversity of
weed communities. Therefore, in these areas, the seed bank could restore weed taxonomic diversity
following changes in management practices, but functional diversity would still remain limited.
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