The taxonomic status of this species is uncertain. It is considered variously as a synonym of Narcissus jonquilla subsp. jonquilloides, of N. jonquilla subsp. willkommii, or Narcissus assoanus. Several morphological characteristics of this plant are rather stable within the known population and represent variability extremes in Narcissus assoanus or Narcissus jonquilla descriptions.

However the taxon is accepted as valid in Portugal (e.g., Carapeto et al. 2017) and we assess the species as valid pending further taxonomic research.

This species is currently restricted to a small section of the Quarteira River in the region of Algarve, southern Portugal. The area of occupancy (AOO) and extent of occurrence (EOO) are estimated at 16 km². Over the past century, the species has faced a large decline in EOO, including the complete destruction of a large subpopulation by the construction of a road in the 1990s and the disappearance of at least two small groups of individuals due to invasive species expansion and river bank erosion in the recent years. Another subpopulation has not been reported since the 1970s. Based on this, the species is estimated to have faced a 50% decline in its EOO over the past three generations (45 years). The main threats to the species are the expansion of the invasive plant Arundo donax, water management activities such as erosion and vegetation control in parts of the river bank, and future plans for the construction of dams (weirs). Although the causes of disappearance in some sites are better known than in others, an ongoing decline in habitat quality, number of subpopulations and number of mature individuals has been inferred in four estimated locations. Based on this information, the species is listed as Endangered (EN A2c; B1ab(iii,iv,v)+2ab(iii,iv,v)).

Further monitoring regarding population trends and threats and ex situ conservation strategies should be developed. Additional research to confirm the distribution of the plant, as well as the taxonomic identity of the species, is also required.

This species is endemic to southern Portugal where it has a very narrow distribution range in the Quarteira River basin in the central region of Algarve (Carapeto et al. 2017). Although, in the past century, it was known to have a wider distribution, with an EOO estimated at circa 525 km² (Carapeto 2006), its current EOO and AOO are both estimated at 16 km².

Old records suggesting the species occurred in the province of Cadiz in the region of Andalucía, Spain (Valdés et al. 1987) could not be verified, nor have new specimens been recorded in this country again (J. Arroyo pers. comm. 2016); therefore, these records from Spain have been excluded from the present assessment.

This species is known from several subpopulations scattered along a 5 km stretch of river in the central region of Algarve. In 2018, the most recent census estimated the number of mature individuals at c. 1,426, based on observation of 13 sites and estimation in 12 sites, however, this number may be an underestimation of the population since the year was not favourable to early flowering species (A. Carapeto pers. comm. 2018).

In the past, other subpopulations were known in the region. However, the causes of disappearance in some sites are better known than in others. One of those lost subpopulations, where the species was reported to be very abundant, was completely destroyed by the construction of a road in the 1990s. Another subpopulation has not been reported since the 1970s. Between 2002 and 2010-12, the population seemed stable in numbers, although its habitat was still declining in quality due to Arundo donax expansion and other minor threats, particularly vegetation control in one part of the river bank. In 2018, population monitoring showed that at least three small groups of individuals disappeared due to the expansion of A. donax and river bank erosion. Over the last 45 years (equivalent to three generations), this species is estimated to have experienced a decline in more than 95% of its EOO, which is inferred to represent a population reduction of, at least, 50% (A. Carapeto pers. comm. 2018).

This plant is a bulbous geophyte found on riverbanks or riverbeds of temporary streams, over rocky substrates or argillaceous banks, between 20 and 60 m asl. Its yellow and scented flowers bloom in late winter (Carapeto et al. 2014).

In the past, road development was the cause of destruction of, at least, one large subpopulation; the threats that triggered the loss of other subpopulations remain unknown. Potential major future threats are the construction of small dams along the stream in the last site where it is known to remain, causing water levels to rise and the direct destruction of population. Current threats to the species are habitat degradation due to the presence of the invasive giant reed Arundo donax along riverbanks, erosion and vegetation control in river margins. Collection of bulbs and flowers from the wild is an additional threat that may also occur, although its scale is still unreported.

This species presents ornamental interest due to its attractiveness, and there is evidence of seed and bulb trading online (A. Carapeto pers. comm. 2014).

The species is assessed as EN for the Portuguese national Red List (Carapeto et al. 2020). This species is not legally protected but the only site known at present is almost entirely located within the Natura 2000 site Ribeira de Quarteira (Protected Planet 2017).

Further monitoring regarding population dynamics and threats is necessary and a conservation plan should be developed, based in the establishment of new subpopulations ex situ to avoid the influence of stochastic factors that may drive the species to extinction (Carapeto 2006). Additional research is required to confirm the distribution of the plant, as well as the taxonomic identity of the species.