A perennial herb of periodically flooded brackish grassland in unimproved coastal grazing marshes, at the edges of ditches and in trampled ground at the base of sea walls; also locally in the uppermost parts of saltmarshes. Lowland.
The 1962 Atlas suggested a marked decline of this species, but it was much under-recorded until the 1980s, and is now known to be still present (and sometimes abundant) at many sites from which it was thought to have been lost. Nevertheless, many populations have declined due to drainage and improvement of its habitat. Where salinity is reduced by sea-defence schemes it readily hybridises with A. geniculatus and eventually disappears, leaving the hybrid behind.
Suboceanic Southern-temperate element.
Light (Ellenberg): 8
Moisture (Ellenberg): 7
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 5
Salt Tolerance (Ellenberg): 3
January Mean Temperature (Celsius): 4.6
July Mean Temperature (Celsius): 16.4
Annual Precipitation (mm): 826
Count of 10km squares in Great Britain: 92
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 1
Atlas Change Index: 0.3
Scarce Atlas Account
Alopecurus bulbosus Gouan
This coastal species is a perennial grass of damp brackish turf, found in winter-wet hollows in unimproved grazing marshes, at ditch edges and on trampled cattle droves at the base of sea and river walls. In these habitats it is usually the dominant species, but it can also occur in mixed swards where saline water reduces competition. It tolerates quite high levels of salinity, but is a species of brackish grasslands, not a salt-marsh plant. The most faithful associates are Carex divisa, Festuca rubra, Juncus gerardii, Poa humilis, P. pratensis and Trifolium fragiferum, with Ranunculus sardous at the drier edges of populations. The common A. geniculatus is often present with A. bulbosus, growing in the wettest parts of the sites and the two species can grow in close enough proximity to produce the hybrid A. x plettkei. Puccinellia distans can occur at particularly brackish, wet sites.
A. bulbosus has two quite short growth periods, in the autumn to start new leaves, and for about 100 days between mid-April and July to flower and seed (Trist 1981). The rest of the time it is dormant and inconspicuous.
It appears to have been under-recorded in the 1960s and 70s, probably because of its flowering so early, for only about three weeks from mid-May into June - with the spikes quickly breaking up afterwards. However, searches made in the 1980s showed that this species persists in many of the areas with historical records (FitzGerald 1989; Pearman 1990; Trist 1981). In dormant periods in particular, its ‘bulbs’, the swollen stem bases, can survive flooding with full strength seawater and major disturbance such as ploughing and earth moving. However, in spite of its excellent adaptations for withstanding such traumas and its decline since 1900 being less drastic than had been supposed, A. bulbosus is threatened by exploitation of its habitat. It can be obliterated by intensive drainage and agricultural changes, and by industrial and leisure developments. The pressure on the deceptively empty-looking expanses of grazing marshes, and ‘useless’ areas of marginal coastal grassland, is increasingly fierce.
This species is endemic to Europe, where it is found on northern and western coasts, and as far east as northwest Yugoslavia.
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.