Zostera noltei

Tracheophyta MagnoliopsidaZosteraceaeZosteraZostera noltei

Ecology

Although a coastal species, this perennial is found at higher levels of the shore than other Zostera species. It grows in sheltered estuaries and harbours, where it is found on mixed substrates of sand and mud. Plants are often concentrated in pools or runnels on the shore. Lowland.

Status

Native

World Distribution

Eurasian Southern-temperate element.

Broad Habitats

Littoral sediment (includes saltmarsh and saltmarsh pools)

Light (Ellenberg): 8

Moisture (Ellenberg): 11

Reaction (Ellenberg): 8

Nitrogen (Ellenberg): 5

Salt Tolerance (Ellenberg): 8

January Mean Temperature (Celsius): 4.2

July Mean Temperature (Celsius): 14.9

Annual Precipitation (mm): 1020

Length: 12

Perennation - primary

Perennial

Life Form - primary

Perennial hydrophyte (perennial water plant)

Woodiness

Herbaceous

Clonality - primary

Rhizome far-creeping

Count of 10km squares in Great Britain: 159

Count of 10km squares in Ireland: 36

Count of 10km squares in the Channel Isles: 4

Atlas Change Index: -0.51

JNCC Designations

NBNSYS0100006056

Scarce Atlas Account

Scarce Atlas Account: 

Zostera noltii Hornem.

Dwarf eelgrass

Status: scarce

 

This is usually the most accessible of the three British Zostera species. It is found highest on the shore in sheltered estuaries and harbours, often adjacent to lower saltmarsh communities, and never below the low-water mark. It is found typically on mixtures of sand and mud, varying in consistency from firm to soft (Gubbay 1988), often in pools or runnels, although it is able to withstand more prolonged exposure than the other Zostera species. It can form extensive populations, as at Maplin Sands, where it covers 325 ha., and sometimes grows amongst stands of Spartina anglica (Gubbay 1988).

Z. noltii is a perennial, flowering in mid-late summer, with seed germination in the autumn. Vegetative dispersal of rhizome fragments is probably the usual means of colonising new sites.

Some of the apparent decline may he attributable to past misidentification, the recording of strandline specimens, or to purely temporal effects of natural variation of estuarine substrates. Whilst the apparent decline from the Moray Firth, Firth of Forth or Solent area might be attributed to pollution, it is difficult to reconcile this with the survival of populations around the Thames estuary. Invasive stands of Spartina anglica could pose a threat at some sites. 

The plant is recorded around European coasts from the Mediterranean to south-western Norway and Sweden.

 

M. Scott

Atlas text references

Atlas (304d)
den Hartog C
1970.  The sea-grasses of the world.
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Meusel H, Jäger E, Weinert E
1965.  Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.