<br> Aims<br> : This study presents a novel characterization of agrestal plant communities associated with traditional, less intensively managed Mediterranean agro-ecosystems, focusing on the influence of seasonal phases, soil-, and land-use conditions, and the presence of obligate arable plant species.<br> Study area<br> : The island of Lemnos, North Aegean.<br> Methods<br> : The vegetation was recorded in spring and fall. We sampled 174 plots located in fields cultivated with cereals and pulses and in fallow and stubble fields across the island. We used non-metric multidimensional scaling (NMDS) to analyze compositional patterns and identify differences between seasons. NMDS and modified TWINSPAN clustering were applied to spring plots to distinguish plant communities and their differential species. Edaphic and other environmental influences were evaluated using a geological map and ecological indicator values. The frequency and distribution of obligate arable plant species were also assessed.<br> Results<br> : Fall vegetation was dominated by late-flowering annuals, biennials, and perennials colonizing fields after harvest. In spring, four distinct spring plant assemblages were identified in fields of winter cereals and pulses, structured along soil gradients ranging from acidic sandy to base-rich loamy soils and from dry to temporarily wet soils. Crop type and fallowing were also found to influence community structure. The island supports a high number of obligate arable species, including several threatened ones.<br> Conclusion<br> : Our findings highlight the ecological and botanical importance of Lemnos’ less intensively farmed agricultural landscape. Soil heterogeneity and seasonal phases promote considerable species and community diversity, resources for wildlife, and the persistence of specialized and rare arable plant species. In the face of increasing agricultural intensification across Europe, the conservation value of less intensive agro-ecosystems is evident. Lemnos offers a rare opportunity to preserve segetal biodiversity<br> in situ<br> .<br> <br> <br> Taxonomic reference<br> : Euro+Med (2006-).<br> <br> <br> Syntaxonomic reference<br> : Mucina et al. (2016).<br> <br> <br> Abbreviations<br> : EIVE = Ecological Indicator Values for Europe; IUCN = International Union for Conservation of Nature; LC = Least Concern (Red List category); NT = Near Threatened (Red List category); NMDS = Non-metric Multi-Dimensional Scaling; PERMANOVA = Permutational Multivariate Analysis of Variance; PERMDISP = Permutational Multivariate Analysis of Dispersion; TWINSPAN = Two-Way Indicator Species Analysis; VU = Vulnerable (Red List category).<br>
