Antithamnionella ternifolia

Invasive Species Information

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What Is Antithamnionella ternifolia?

Habitat: Aquatic, marine
Distribution in Ireland: West Ireland coastal areas

Status: Established

Family name: Ceramiaceae

Common name/sAntithamnionella sarniensis Lyle, red seaweed.

Reproduction: The species has a rapid growth rate and grows abundantly on all types of substrata including eelgrass leaves, algae, animals, pebbles and artificial materials, over a wide range of conditions.

This species shows a wide temperature tolerance. Sexual reproduction is rare with the main method of reproduction being fragmentation.

Antithamnionella ternifolia

Antithamnionella ternifolia

Antithamnionella ternifolia

Thallus of uncorticated, monosiphonous, prostrate axes bearing erect branches.

 

Cells with 1-4 determinate branchlets, inconsistent in number per cell and in branching pattern of branchlet.

Gland cells lateral and sessile on 2nd-5th cell of branchlet axis or on branches of the branchlet.

Recent studies on ecology, morphology and reproduction have established Antithamnionella sarniensis and Antithamnionella spirographidis as distinct species.

 

Genetic isolation also demonstrated by complete failure of interspecific crossing. 

Antithamnionella ternifolia

Procarps, 1-3, borne near branch apices on basal cells of successive branchlets usually reduced to one cell beyond the basal (supporting) cell.

 

Antithamniella has sometimes been included in the genus Antithamnion, but differs in features of branching, position of gland cells, fewer procarps borne on reduced branchlets and tetrahedral division of tetrasporangia.

It has spread fairly rapidly around the coasts in western Ireland . It spreads mainly through remote dispersal as it grows on ropes and ships' hulls.

How To Identify Antithamnionella ternifolia?

Red Seaweed - Antithamnionella ternifolia ID Guide

Thallus
Frond: Red Colour

Holdfast

Red Seaweed - Antithamnionella ternifolia
Red Seaweed - Antithamnionella ternifolia

Antithamnionella ternifolia  ID Guide

Antithamnionella ternifolia

Antithamnionella ternifolia

Why Is Antithamnionella ternifolia A Problem?

Antithamnionella ternifolia is an alien (non-native) invasive marine plant, meaning it out-competes crowds-out and displaces beneficial native marine species that have been naturally growing in Irish coastal waters for centuries.

 

  • Displacement of native species

  • Introduction of new pests and parasites which affect native species

  • Habitat alteration

  • Changes in food webs, particularly through dietary competition and predation

  • Degradation of integrity of gene pool through hybridisation

  • Associated effect of commercial harvesting Improved water quality

  • Fouling of ships, marinas, moorings, nets, shellfish & aquaculture structures

  • Competition with and predation on aquaculture sp. Food source to humans and wildlife

  • Damage to nets

  • Increased productivity of previously uncolonised habitats 

European Communities (Birds and Natural Habitats) Regulations 2011 non-native invasive plant species A-Z (Updated 2017)


There are currently 35 invasive plant species listed in the European Communities (Birds and Natural Habitats) Regulations (annex 2, Part 1)...
 
Click on a species from the following list to find out more regarding non-native species subject to restrictions under Regulations 49 and 50.

  1. American Skunk-CabbageLysichiton americanus

  2. Brazilian Giant-RhubarbGunnera manicata

  3. Broad-Leaved RushJuncus planifolius

  4. Cape PondweedAponogeton distachyos

  5. Cord-GrassesSpartina (all species and hybrids)

  6. Curly Waterweed - Lagarosiphon major

  7. Dwarf Eel-GrassZostera japonica

  8. FanwortCabomba caroliniana

  9. Floating PennywortHydrocotyle ranunculoides

  10. Fringed Water-LilyNymphoides peltata

  11. Giant HogweedHeracleum mantegazzianum

  12. Giant KnotweedFallopia sachalinensis

  13. Giant-RhubarbGunnera tinctoria

  14. Giant SalviniaSalvinia molesta

  15. Himalayan BalsamImpatiens glandulifera

  16. Himalayan KnotweedPersicaria wallichii

  17. Hottentot-FigCarpobrotus edulis

  18. Japanese KnotweedFallopia japonica

  19. Large-Flowered WaterweedEgeria densa

  20. Mile-a-Minute WeedPersicaria perfoliata

  21. New Zealand PigmyweedCrassula helmsii

  22. Parrots FeatherMyriophyllum aquaticum

  23. Red AlgaGrateloupia doryphora

  24. RhododendronRhododendron ponticum

  25. SalmonberryRubus spectabilis

  26. Sea-Buckthorn Hippophae rhamnoides

  27. Spanish Bluebell Hyacinthoides hispanica

  28. Three-Cornered LeekAllium triquetrum

  29. WakameUndaria pinnatifida

  30. Water ChestnutTrapa natans

  31. Water FernAzolla filiculoides

  32. Water LettucePistia stratiotes

  33. Water-PrimroseLudwigia (all species)

  34. WaterweedsElodea (all species)

  35. WireweedSargassum muticum

Additional Non-Native Plant Species identified as Medium Risk on Ireland's Biodiversity List...

Common name 

African woodsorrel

American skunk cabbage

Annual bur-sage

Antithamnionella ternifolia

Barberry

Black currant

Brazilian waterweed

Butterfly-bush

Canadian-fleabane

Clover broomrape

Creeping Bellflower

Dead man's fingers

Douglas fir

Early goldenrod

False acacia

Field penny-cress

Garden lupin

Giant rhubarb

Hairy rocket

Himalayan honeysuckle

Himalayan knotweed

Holm oak

Japanese barberry

Japanese honeysuckle

Japanese rose

Leafy spurge

Least duckweed

Narrow-leaved ragwort

New Zealand bur

Ostrich fern

Pampas grass

Pitcherplant

Red oak

Red sheath tunicate

Rock cotoneaster

Rum cherry

Russian-vine

Salmonberry

Sea-buckthorn

Sycamore

Three-cornered garlic

Traveler's-joy

Tree of heaven

Turkey oak

Virginia-creeper

Warty cabbage

Water fern

Wild parsnip

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