A foetid, often prostrate annual of disturbed, nutrient-rich soil on sandy shingle beaches, sand dunes and coastal cliffs, where the soil is enriched by the droppings of sea-birds. It was formerly a ruderal of places enriched with animal dung. Lowland.
This species had declined dramatically before 1930, perhaps because of the change from horse to tractor power, and the declining use of dung as a fertiliser. By 1930 it was virtually confined to coastal habitats, and even here it has continued to decline for reasons which are unclear.
As an archaeophyte C. vulvaria has a Eurosiberian Southern-temperate distribution; it is widely naturalised outside its native range.
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Light (Ellenberg): 7
Moisture (Ellenberg): 4
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 9
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4.1
July Mean Temperature (Celsius): 16.1
Annual Precipitation (mm): 752
Height (cm): 35
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 180
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 6
Atlas Change Index: -2.6
Plantatt Conservation Status
RDB Species Accounts
Chenopodium vulvaria L. (Chenopodiaceae)
Status in Britain: VULNERABLE. WCA Schedule 8.
Status in Europe: Not threatened.
C. vulvaria was characteristic of a wide variety of bare, nitrogen-enriched habitats particularly in coastal areas, from arable fields and rubbish dumps to sandy or gravelly waste ground or tracks. In all these habitats it would be part of a typical open weed flora, with a vegetation cover of 25% or less. It is now found at only three regular sites, all of which are coastal. In Suffolk, its habitat is sandy shingle in an open community in which Glaucium flavum, Lepidium latifolium, Ononis spinosa, Reseda lutea and Senecio viscosus are prominent. In Dorset it has an atypical habitat on bare ground at the top of 40-metre-high cliffs where erosion from spray and wind and disturbance by gulls keep open a strip up to a metre wide. Here the associates include Beta vulgaris, Chenopodium album, Erodium cicutarium, Malva sylvestris and Phleum arenarium in addition to some of those listed above. In Kent its associates in open communities on sandy tracks in dune grassland included C. album, E. cicutarium, Honkenya peploides, Polygonum aviculare and Solanum nigrum. It can tolerate very high levels of nitrogen.
This annual species germinates in spring, and flowers from July to September. A second germination and flowering may occur in August and September, if a dry summer has been followed by rain. In its cliff site it germinates only where the majority of the substrate is soil, and not where there is rock or rock with soil pockets.
The recent decline of C. vulvaria in Britain has been remarkable. Once known from over a hundred hectads, it declined to fifteen by 1960, and is restricted to only three regular sites today. Sprays in arable fields, tidier rubbish dumps, housing developments and, above all, less open habitats in its coastal niches have accounted for this loss. At the Suffolk site, the colonies had been severely threatened by rabbit-grazing, and by soil compaction from vehicles. However, they are now fenced against both. Numbers have fluctuated greatly, with maxima in recent years of 125 plants in 1990 and 83 in 1986. Conservation management now involves opening up the enclosure during winter and spring to allow rabbits to graze down robust plants (especially Glaucium flavum and Lepidium latifolium), and rotavating the plot in late April to provide open ground for germination (Odin 1990; P. Holmes, pers. comm., 1996). The Dorset site is kept open by the elements and, although only a few metres from the coast path, seems quite secure. Numbers fluctuate considerably: a seven year period has seen two years with fewer than ten plants, two years of over 2,000, with the other three at about 100 plants. There are rabbits on site, with burrows right by the plants, and this may be one of the reasons for the fluctuations. In one year a few plants were found on the beach below, and in two years some appeared by the coast path. In 1996 only a few plants were found on the cliff edge, but there were over 500 plants in bunkers on the adjoining golf course.
C. vulvaria is widespread throughout Europe, north to Denmark, and is found also in North Africa and South-West Asia. Little is known of its current European status.
D. A. Pearman
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1980)
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
1999. British Red Data Books. 1. Vascular plants, edn 3.