The total number of individuals is less than 5,000 individuals, with only a few specimen per subpopulation and generally less than 50 per subpopulation. Several extinctions of subpopulations have taken place in the last 100 years and the population trend is still decreasing. The reason for that is habitat loss and degradation being caused by a variety of threats including recreational activities, abandonment of grazing, competition with invasive species, building of infrastructure, climate change leading to an increase in storms. This species is therefore considered as Vulnerable.

This plant is endemic to Europe (Euro+Med Plantbase 2006-2010). It is found in Galicia in Spain and occurs in France in the Massif Armoricain, Manche to Vendee, and with one record in Guironde. In the United Kingdom, it is found in Wales, along the coast of Cornwall and Devon and on the Isles of Scilly.

This is a rare species.

In France, there are 72 small localities, with generally two to three dozens of individuals per locality (N. Juillet pers. comm. 2010).

In Spain, 858 individuals were recorded in Galicia in 12 localities. Most subpopulations are fragmented and with no more than 60 individuals each, many with just one specimen.
 
In the UK, a total of 220-250 individuals has been reported. It is found at 38 sites and strong declines are suspected to have happened over the last 100 years with former habitat being lost. In Cornwall, it is found at 19 sites and has gone extinct at 18 sites, in Devon there are nine present and seven formerly known localities, in Wales it is four sites at present and four extinct localities. There are four locations on the Isles of Scilly (Plantlife International 2006).

This species occurs in cliffs with water seepage, small rivers on sandy coasts and beaches and in rocky areas with freshwater falling into the sea, depressions in "grey" dunes and pebble. It is always associated with a flow of freshwater. The fruits of this plant float in seawater and are dispersed that way. Rumex rupestris often acts as pioneer species but is a poor competitor (Plantlife International 2006).

In France the habitat of this species seems to be stable.

The species occurs in the following Habitats Directive habitats (Commission of the European Communities 2009):

• 1220 Perennial vegetation of stony banks
• 1230 Vegetated sea cliffs of the Atlantic and Baltic Coasts
• 2190 Humid dune slacks

Hybridisation with R. conglomeratus (UK) and R. crispus (France) has been reported as a reported threat. Trampling and tourist activities, as well as habitat deterioration due to infrastructure development, deviation of the river courses, silting-up, and oil contamination (Prestige accident) are also important threats.

In the UK, coastal defence work to stop erosion has caused the extinction of some sites. Local extinctions took place due to erosion itself caused by winter storms. Climate change might increase the frequency of storms and therefore make it harder for the species to naturally recolonize. It is noted that coastal defence works can also be beneficial to the species survival.

Where the species occurs in dune systems, the abandonment of grazing led to scrub encroaching which proves to be high competition for the species. Especially the Hottentot fig (Carpobrotus edulis), an invasive plant from South Africa, affects the Rumex rupestris populations (Plantlife International 2006).

This species is not used.

This species is listed on Annexes II and IV of the Habitats Directive and is listed under Appendix I of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention). It is protected in the national legislation (Annex I) in France, regional legislation of Galicia (in Spain) and is considered as Endangered (Criteria E) in the Spanish Red List, after a monitoring programme of six years. Most of its habitat has been declared LIC for the Habitat Directive or are covered by a National Park or Natura 2000 sites.
In the UK, it is classed as Endangered C2(ai), protected under national law and included as priority species in the UK Biodiversity Action Plan. Of the known Rumex rupestris plants, 85% are included in protected areas. Monitoring and site management are in place (Plantlife International 2006).

Ex situ conservation actions are in place in France and in the UK. Several conservation measures are recommended: investigations of the Spanish coast to look for new localities, inclusion in the Spanish national legislation, genetic studies to assess its variability and the possibility to reintroduce the plants in adequate habitat, studies on the biology of the species, its reproduction.