Banasiak et al. (2016), in their review of Apiaceae subtribe Daucinae, placed this species in genus Daucus, and assigned a new epithet 'rouyi' as the epithet polygamus is not available in Daucus because it is preoccupied by D. polygamus Gouan (1773).

Daucus rouyi Spalik & Reduron is a secondary wild relative of Carrot, D. carota subsp. sativus var. sativus Hoffm., and Purple Carrot, D. carota subsp. sativus var. atrorubens Alef. (GRIN 2019).

The native range of Daucus rouyi is restricted to the central-southern area of the Mediterranean Basin, spanning coastal areas of Algeria and Tunisia to Sardinia and Corsica. Its extent of occurrence is estimated to exceed 60,000 km², while its area of occupancy is estimated to lie between 160 and 168 km². Although the value for AOO could represent an underestimate owing to an incomplete botanical inventory, it is suspected that the growing areas for this species have been relatively well-sampled, particularly across Corsica and Sardinia. The species is not thought to be known from a large number of locations, but it is estimated that the number of locations exceeds 10. In general, the species is threatened by the modification of the coastal areas in which it grows by road construction and tourism activities. Additionally, very localised threats have been observed on the islands of Corsica and Sardinia, owing primarily to littoral tourism development, and these are also suspected to impact the species in the Algerian and Tunisian parts of its range. The coastal habitat in which it occurs is naturally fragmented, and habit fragmentation is being exacerbated as a result of littoral tourism. It is inferred that this is contributing to an ongoing decline in the area of occupancy and habitat area, as well as in terms of extent and quality.

The global population is suspected to be large, with more than 16,000 plants on Corsica alone. The population in Corsica has been increasing since monitoring began in 1998, but it is suspected that the expansion of littoral tourism may be contributing to a decreasing population trend globally. Although the species' habitat is increasingly fragmented, it is not clear whether the population can also be inferred to be severely fragmented; some very large subpopulations exist and there is suspected to be connectivity between some subpopulations, thus it seems unlikely that more than 50% of the global population occurs in small, isolated subpopulations. 

Given a restricted AOO and an inferred ongoing decline in area of occupancy and habitat area, extent and quality, the species is close to qualifying for a threatened category under criterion B2. Daucus rouyi is therefore assessed as Near Threatened B2b(iii). In Corsica and Sardinia, the plant is well researched and part of active conservation management, however, there is less clarity around its contemporary status in North Africa; research is urgently required to ascertain its population status and trend, distribution, and the severity of threats in this part of the range.

The native distribution of Daucus rouyi spans central-north Africa to Sardinia and Corsica (Quézel and Santa 1963, Pottier-Alapetite 1979, Pignatti 1982, USDA, Agricultural Research Service, National Plant Germplasm System 2019). In Sardinia, it is known from nine localities around the coast of the island, while in Corsica it has been recorded from thirty localities but all within the vicinity of the Gulf of Porto-Vecchio (Superbielle 2016). Six historical localities are known in Tunisia and the plant is still present at five of these; an additional locality in northeastern Tunisia was discovered recently (E. Véla pers. obs. 2008, P. Leboulanger pers. obs. 2014, R. El Mokni pers. obs. 2018). In Algeria, all known observations have been recorded along the coast of Annaba and El Taref provinces (G. de Bélair pers. obs. 1983–2014, E. Véla pers. obs. 2008). The precise elevational range for the species is not known but it is thought to be restricted to low-lying littoral land and dunes.

According to Pozzo Di Borgo et al. (2000) just over 11,000 individual plants were recorded in Corsica between 1998–2000, but in 2010 the number was revised to over 9,000 and in 2016 to over 15,000 (Superbielle 2016). However, more research is needed on the current population size and trend of this species across its whole range. Despite this documented population increase, it is suspected that the global population trend may be decreasing, as the coastal areas in which it grows are rapidly being modified by road construction and tourism activities (Mezghani et al. 2019). A better understanding of population status is needed, with research into its North African range particularly important in establishing this.

Daucus rouyi is a herbaceous perennial growing between 15–50 cm tall; its polycarpic chamaephytic habit distinguishes it, the small erect petals (±1.3 mm), the widely winged mericarps (1.9–3.1 mm width), lack of spines on secondary ridges and lack of trichomes on primary ridges and a chromosome number 2n = 20 (Constance et al. 1976, Martínez-Flores et al. 2019). It occurs in coastal areas growing in sandy dunes, seeming to withstand salt spray (Bensettiti et al. 2002). It grows on consolidated dunes subject to slight wind or pedestrian erosion (E. Véla pers. obs. 2008). It is found in semi-closed, sandy forests and seems to be promoted by leaf litter (Superbielle 2016) and by the alien plant Carpobrotus stabilising the dunes (Pozzo di Borgo and Paradis 2000).

In general, the species is threatened by the modification of the coastal areas in which it grows by road construction and tourism activities (Mezghani et al. 2019). Very localised threats to this species have also been observed on the islands of Corsica and Sardinia and seem to be similar in Algeria and Tunisia (E. Véla pers. obs. 2008). In Sardinia, urban development has been observed in the areas of Portoscuso and in the coastal areas of Arbatax and Pine port; additionally, the construction of transport infrastructure to beaches and coastal areas has reduced the habitat for this species (Fenu et al. 2016). In Corsica, urbanization, landscaping, trampling, pollution through waste deposits and the natural closure of environments present threats to this species (Superbielle 2016). The introduction of invasive Carpobrotus species has been considered an additional threat because of displacement (Bensettiti et al. 2002), however, Carpobrotus species also can contribute to the stabilisation of dunes disturbed and eroded by increased human activity (E. Véla pers. obs. 2002–2008) and this been suggested to be potentially beneficial to the colonisation of D. rouyi in degraded habitats (Pozzo di Borgo and Paradis 2000); further work would be required to assess the long-term implications here.

Daucus rouyi is a wild relative of, and potential gene donor to crop carrot, D. carota L. (USDA, Agricultural Research Service, National Plant Germplasm System 2019).

The genus Daucus is listed in Annex I of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) which aims to guarantee sustainable agriculture and food security through the conservation and sustainable use of plant genetic resources for food and agriculture, as well as ensuring the fair and equitable sharing of the benefits arising out of their use (FAO 2009). D. rouyi is also listed under Appendix I of the Convention on the Conservation of European Wildlife and Natural Habitats (1979) and Annex II of the Habitats Directive (1992). Two D. rouyi germplasm accessions of wild origin are held worldwide: one accession was collected in Tunisia and is held by the North Central Regional PI Station in the USA; the other was collected in Sardinia and is held at the Millennium Seed Bank (Genesys Global Portal on Plant Genetic Resources 2019, USDA, Agricultural Research Service, National Plant Germplasm System 2019).

Six botanical gardens are listed as sites of ex situ conservation for this species (BGCI 2019). On Corsica, it has been collected from two areas of Community Importance - Delta de l'Oso; punta di Benedetty et Mura dell'Unda and Embouchure du Stabiaccu; Domaine Public Maritime et îlot Ziglione (Protected Planet 2019). In Sardinia, it is present in four sites of Community Importance (Stagno di Porto Botte, Promontorio, Porto Pino's dunes and wetlands, and the Islands of Travolara, Molara and Molarotto) and in three International Plant Areas (the Islands of Travolara, Molara and Molarotto, Santa Caterina pond, Porto Pino, and Capo Teulada) (Santo et al. 2013). In Algeria, it has been collected frequently from El Kala UNESCO-MAB Biosphere Reserve (Protected Planet 2019). In Corsica, it is nationally protected and there are two localities with re-introduced D. rouyi& on the territory of the Conservatoire du Littoral (Gigot and Juillet 2011).

Daucus rouyi has been included in a number of regional conservation assessments at differing scales with differing extinction risk categories assigned: in a Red List for Europe in 2011, it was assessed as Endangered; in the 2012 Red List for Threatened Species in France, it was listed as Critically Endangered, CR B2ab(ii,iii,v); in a Red List for Italy in 2013, it was assessed as Endangered, EN B1ab(iii,v) + B2ab(iii,v), and in a Red List for Corsica in 2015, it was assessed as Vulnerable, VU B2ab(iii) (Gigot and Juillet 2011, UICN France, FCBN & MNHM 2012, Rossi et al. 2013, Dealge et al. 2015). In a recent study into the distribution and conservation status of carrot wild relatives in Tunisia, with regard to combined (in situ and ex situ) conservation, D. rouyi was assigned a low relative priority for further conservation (Mezghani et al. 2019).