Water primrose	Status LU: absent. 1st record: n/a.
	Groussbléieg Waasserprimmel	Status Eur.: established. 1st record: FR 1830s.1 IAS of EU concern (2016).
	Jussie à grandes fleurs, Grande J.	RA: ISEIA: A0, Alert List. Harmonia+: 0,28
	Großblütiges Heusenkraut	Wikipedia: | Wikispecies: | CABI
	Waterteunisbloem	Back to the list of neophytes

Report the species

→ Report Ludwigia grandiflora to the National Museum of Natural History.

Brief description

Ludwigia grandiflora (Michx.) Greuter & Burdet is an amphibious species living in ponds, lakes, ditches, channels and slow-running rivers as well as in humid meadows. It shows a high tolerance to different water levels. Its growth is favoured by water eutrophication but the plant is able to develop in oligotrophic environments. Invasive spread across watersheds is almost exclusively clonal and brought about by the dispersal of vegetative propagules by waterflow. Water primroses are highly detrimental to the environment in western Europe. They quickly develop and make very thick monospecific floating carpets at the surface of water bodies. They alter the physico-chemical quality of water (reduction of light and dissolved oxygen) and possess an allelopathic activity that influences the water quality throughout the year and reduces the germination and survival rates of other plant species. They outcompete most native water plants and create an anoxic environment detrimental to many plant and animal species. In addition, they modify water flow and cause wetland drying (Branquart et al. 2013).

IAS of Union concern

In 2016, Ludwigia grandiflora (Michx.) Greuter & Burdet was added to the list of invasive alien species of Union concern (Anonymous 2016) which implies that member states shall take all necessary steps to prevent it’s unintentional introduction or spread.

Status and distribution in Luxembourg

Ludwigia grandiflora (Michx.) Greuter & Burdet has not yet been observed in Luxembourg (MNHNL, iNaturalist & GBIF 2020).

Risk assessment

ISEIA protocol

A0 (3+3+2+3) = Alert List. First assessed 24 January 2019 by Manou Pfeiffenschneider and Christian Ries.

Harmonia+ protocol

Overall risk score 0,28 = (Overall Invasion score 0,46 x Overall Impact score 0,62) (Ries et al. 2020).

Worldwide distribution

Bibliography

• Anonymous, 2016. Commission implementing regulation (EU) 2016/1141 of 13 July 2016 adopting a list of invasive alien species of Union concern pursuant to Regulation (EU) No 1143/2014 of the European Parliament and of the Council. Official Journal of the European Union L 189: 4-5.
• Branquart, E., I. Stiers, S. Vanderhoeven, W. Van Landuyt, F. Van Rossum & F. Verloove, 2013. Harmonia database: Ludwigia grandiflora (Michx.) Greuter & Burdet. Harmonia version 1.2, Belgian Forum on Invasive Species. URL: http://ias.biodiversity.be [accessed on 2019-11-21]
• CABI, 2021. Ludwigia grandiflora. In: Invasive Species Compendium. Wallingford, UK: CAB International. URL: www.cabi.org/isc [accessed 2021-03-04]
• MNHNL, iNaturalist & GBIF, 2020. Ludwigia grandiflorain MNHNL-mdata, online portal combining species observation from Recorder-Lux, iNaturalist and GBIF. National Museum of Natural History, Luxembourg. URL: https://mdata.mnhn.lu [Accessed 2020-03-02]
• Ries, C., Y. Krippel & M. Pfeiffenschneider, 2020. Risk assessment after the Harmonia+ protocol of invasive alien vascular plant species in Luxembourg. Bull. Soc. Nat. luxemb. 122: 197-205. [PDF 132 KB]