The status of 102 segetal plant species across 37 European red lists reveals their drastic state of conservation

The declining trend of segetal plant species has been highlighted by small-scale studies scattered around different European countries. Hence, a complete picture of the conservation status of a wide set of segetal plant species in Europe is currently missing. Red lists are elaborated following a similar methodology (developed by the International Union for Conservation of nature (IUCN)) and their compilation represents one way of assessing the conservation status (NT: near threatened; VU: vulnerable; EN: endangered; CR: critically endangered; RE: extinct) of numerous species at a continental scale. Here, we assessed the conservation status of 102 segetal plant species (French national segetal plant list) across the red lists of 37 European countries. Information concerning species presence/absence and residence status (native/archeophyte vs. neophyte) in the different countries was also gathered across a diversity of databases. Of the 102 species considered, over 70 were present in Western and Mediterranean countries and a large proportion was considered as native/archeophyte. Northern countries (Baltic, Scandinavian, British Isles) counted less species and a large proportion was considered as neophytes. Most species (84) were found in 10 countries or more (e.g. Alopecurus myosuroides). Nevertheless, 11 of these were considered as archeophytes/natives in less than 10 countries (e.g. Ridolfia segetum). Seven species were almost always considered as neophytes in the countries where present (e.g. Tulipa spp.). Fifteen species showed restricted distributions, mainly around the Mediterranean Sea (e.g. Nigella spp., Delphinium spp., Silene spp., Hypecoum spp.). On average, red-lists included 16 of the 102 considered species, with important differences between countries (e.g. 0 for Denmark and 51 for Switzerland). Central European countries (e.g. Luxembourg, Belgium, Germany, Austria) usually had the highest count of species considered as CR or RE. On average, each of the 102 considered species was found in 6 national red lists, with important differences across species (e.g. 22 species present in more than 10 lists and 11 in none). Species most frequently considered as CR or RE were Agrostemma githago, Asperula arvensis, Scandix pecten-veneris, Gypsophila vaccaria and flax specialists. Four species with restricted distribution were absent from all lists (Tulipa lortetii, Nigella hispanica subsp. hispanica, Delphinium halteratum subsp. halteratum, Silene conoidea), even though usually considered natives/archeophytes. The state of European segetal flora may be even more drastic as segetal species are not necessarily considered for red-list assessments, even in hot-spots where they are known to be declining (e.g. Spain, Portugal, Italy). Data from south eastern countries was lacking and botanical assessments in these regions may temper the drastic state depicted here. We encourage the elaboration of a European segetal plant list and programs specific to different subsets of segetal plants (i.e. wide distribution but often red-listed vs. restricted distribution).