Invasive alien freshwater jellyfish Craspedacusta sowerbii spotted in Upper Sûre Lake

At the beginning of September 2020, freshwater jellyfish were spotted in the Upper Sûre Lake. Photographs of this jellyfish were sent by divers from the CGDIS Frogmen Group to the Water Management Administration (AGE) and the Nature and Forestry Administration (ANF). This observation made it possible to confirm the presence of the Craspedacusta sowerbii jellyfish in the Upper Sûre Lake.

Craspedacusta sowerbyi by OpenCageIt is true that the term “jellyfish” is reminiscent of marine species with a stinging nature, which can trigger painful skin reactions, similar to a burn, on direct contact with the animal. The freshwater jellyfish, on the other hand, is a harmless relative. Although it belongs to the group of cnidarians, it is completely harmless to humans.

Originally from Asia, the freshwater jellyfish has spread to other parts of the world mainly due to the introduction of aquatic plants and fish. This invasive alien species is no larger than 25 mm in diameter and prefers calm, stagnant waters that warm up considerably in summer.

As this jellyfish requires temperatures often above 20°C over a long period of time, its appearance takes place from July to October with a peak observed from the end of August to the beginning of September.

It should also be noted that these jellyfish prefer clean water. In the evening, they often come to the surface of the water and can be observed there. They can also be admired when diving at greater depths during the day. These jellyfish have also been reported in other surrounding areas. It is very likely that their proliferation will continue as the climate warms.

The problem of the appearance of blue-green algae (cyanobacteria), which is a real concern in many respects for the Upper Sûre Lake, is a phenomenon totally independent of the appearance of the freshwater jellyfish observed and described in this press release.

If you spot any jellyfish, you can report them at the following address: .

Original of the press release by the Nature and Forestry Administration / Water Management Administration

In 1974, the polyp of Craspedacusta sowerbii had already been discovered in Luxembourg by biologist Jacques Dahm, in the river Sûre near Wasserbillig (Dahm 1974):

Dahm, J., 1974. Die Hydrozoen Luxemburgs. Eine Bestandsaufnahme und Beschreibung der in Luxemburg lebenden Hydrozoen. Luxembourg. Mém. sci. asp.-prof. 232 p.

 Page content last updated on 2020-10-13. Last proofread by Caroline Grounds on 2020-09-30.

Publication of leaflets on Fallopia japonica and Impatiens glandulifera

In early spring 2020 the Department for the Environment of the Luxembourg Ministry for environment, climate and sustainable development edited leaflets in German and French about Fallopia japonica and Impatiens glandulifera, in co-operation with the National Museum of Natural History and efor-ersa ingénieurs-conseils. They can be downloaded here in PDF format (~ 4 MB each).

More information on → Japanese knotweed and → Himalayan balsam in Luxembourg.



 Page content last updated on 2020-04-06.

Invasive Alien Species in Europe app

The Invasive Alien Species in Europe app enables the general public (amateurs and professionals) to receive and share information about Invasive Alien Species (IAS) in Europe. It provides details about 66 different IAS that are considered to be of interest to the complete European Union. Users can record pictures of possible Invasive Alien Species together with complementary information about their observation.

Official page of the app:

App Download:

 Page content last updated on 2020-02-27.

Conference NEOBIOTA 2020 @ Vodice, Croatia

The next NEOBIOTA conference will take place in Vodice (Croatia) on September 15-18, 2020 and is organised by Sven Jelaska, professor at the Department of Biology, University of Zagreb.

11th International Conference on Biological Invasions
The Human Role in Biological Invasions: a case of Dr Jekyll and Mr Hyde?

All important information concerning dates, registration, booking, fees, etc. are now available at the NEOBIOTA 2020 website. The abstract submission process will start by the end of February and last until March 31st, 2020.

 Page content last updated on 2020-03-05. Last proofread by Caroline Grounds on 2020-03-05.

Public consultation on action plans for invasive alien species

Press release on 17/12/2019 by the Ministry of the Environment, Climate and Sustainable Development (MECDD)

As provided for by Article 4 of the Law of 2 July 2018 (Mémorial 2018) on certain implementing rules and sanctions of Regulation (EU) No 1143/2014, the draft action plans for invasive alien species (IAS AP) are made available to the public on the website of the Ministry of the Environment, Climate and Sustainable Development.

Currently a public consultation on the action plans for 11 species is underway. All comments on these draft action plans should be sent by e-mail to or by post to the Administration de la nature et des forêts (81, avenue de la Gare, L-9233 Diekirch). The deadline for sending your comments and suggestions is 13 February 2020.

Draft action plans under public consultation

    1. Alopochen aegyptiacus: Egyptian goose, ouette d’Égypte, Nilgans (PDF 1,7 MO)
    2. Elodea nuttallii: Nuttall’s Waterweed, élodée de Nuttall, Schmalblättrige Wasserpest (PDF 1,3 MO)
    3. Heracleum mantegazzianum: Giant hogweed, berce du Caucase, Riesen-Bärenklau (PDF 1,3 MO)
    4. Impatiens glandulifera: Himalayan Balsam, impatiente de l’Inde, Drüsiges Springkraut (PDF 1,4 MO)
    5. Myocastor coypus: Coypu, ragondin, Nutria (PDF 2 MO)
    6. Ondatra zibethicus: Muskrat, rat musqué, Bisamratte (PDF 1,9 MO)
    7. Orconectes limosus: Spinycheek crayfish, écrevisse américaine, Kamberkrebs (PDF 3 MO)
    8. Pacifastacus leniusculus: Signal crayfish, écrevisse de Californie, Signalkrebs (PDF 3 MO)
    9. Procyon lotor: Raccoon, raton laveur, Waschbär (PDF 2,4 MO)
    10. Pseudorasbora parva: Topmouth, goujon asiatique, Blaubandbärbling (PDF 1,2 MO)
    11. Trachemys scripta: pond slider, n/a, Nordamerikanische Buchstaben-Schmuckschildkröte (PDF 1,8 MO)


  • Mémorial, 2018. Loi du 2 juillet 2018 concernant certaines modalités d’application et les sanctions du règlement (UE)n° 1143/2014 du Parlement européen et du Conseil du 22 octobre 2014 relatif à la prévention et à lagestion de l’introduction et de la propagation des espèces exotiques envahissantes. Mémorial A (04/07/2018), 553: 1-4. [PDF]

 Page content last updated on 2020-01-24.

Parliamentary question of 5th September 2019 regarding the European list of invasive alien species

On 5 September 2019, Mars Di Bartolomeo, Member of the Chamber of Deputies, addressed a parliamentary question to the Minister of the Environment regarding the European list of invasive alien species.

Question 1

Which species on this list have been recorded in Luxembourg?

Response from Carole Dieschbourg, Minister for the Environment, Climate and Sustainable Development:

Plants (5 species):

  1. Tree of heaven (Ailanthus altissima)
  2. Himalayan balsam (Impatiens glandulifera)
  3. Giant Hogweed (Heracleum mantegazzianum)
  4. Nuttall’s waterweed (Elodea nuttallii)
  5. Parrot’s feather (Myriophylum aquaticum)

Animals (9 species):

  1. Spiny-cheek crayfish (Orconectes limosus)
  2. Signal crayfish (Pacifastacus leniusculus)
  3. Topmouth gudgeon (Pseudorasbora parva)
  4. Egyptian goose (Alopochen aegyptiacus)
  5. Pumpkinseed (Lepomis gibbosus)
  6. Coypu (Myocastor coypus)
  7. Muskrat (Ondatra zibethicus)
  8. Raccoon (Procyon lotor)
  9. Red eared slider (Trachemys scripta).

Question 2

Given that these species pose a threat to biodiversity and ecosystem services, what is his Ministry’s strategy for more effective eradication, management and control methods to combat the adverse effects associated with this phenomenon?

Response from Carole Dieschbourg, Minister for the Environment, Climate and Sustainable Development:

In accordance with European regulations, Luxembourg’s strategy to counter the environmental and social problems caused by invasive alien species has four main components, namely

  1. prevention,
  2. early detection and rapid eradication,
  3. management,
  4. awareness and training.

There are two scenarios:

  1. the establishment of emerging species and any new invasive alien species detected on national territory is prevented;
  2. populations of widely distributed species are controlled, in order to reduce their environmental and social impacts and avoid further spread.

For widespread species, “Invasive Alien Species Action Plans” have been developed, which include the actions to be implemented for each species. All actions thus defined shall be based on the best scientific knowledge and shall take due account of cost-effectiveness, human health, the environment and animal welfare.

A public consultation will be launched shortly for each action plan.

Original documents

parliamentary question n°1160 of 5 September 2019
parliamentary question n°1160 – reply of 7 October 2019

 Page content last updated on 2019-12-19. Last proofread by Caroline Grounds on 2019-12-19.

Field Guide to Invasive Alien Species in European Forests

The Slovenian Forestry Institute has published a Field Guide to Invasive Alien Species in European Forests which was translated to English and made available as PDF file.

This guide was first prepared in Slovenian, within the framework of the project Awareness Raising, Training and Measures on Invasive alien Species in forests (LIFE ARTEMIS), which is funded by the European Commission in the framework of the LIFE financial mechanism, the Ministry of the Environment and Spatial Planning of the Republic of Slovenia, the City of Ljubljana and the Slovenian Research Agency.

Kus Veenvliet, J., P. Veenvliet, M. de Groot & L. Kutnar (eds.). 2019. A Field Guide to Invasive Alien Species in European Forests. Nova vas: Institute Symbioisis, so. e.; Ljubljana: The Silva Slovenica Publishing Centre, Slovenian Forestry Institute. [PDF 32 MB]

 Page content last updated on 2019-12-12. Last proofread by Caroline Grounds on 2019-12-12.

First record of Solanum rostratum in Luxembourg

Solanum rostratum Dunal was first observed in the wild in Luxembourg on 21 August 2019 by Jörg Zoldan and Annette Steinbach-Zoldan on the border of a maize field in the municipality of Kayl (Southern part of Luxembourg), during a field study on behalf of SICONA.


Solanum rostratum Dunal (spiny or prickly nightshade, Mexican thistle) is a species of nightshade that is native to the US and northern and central Mexico. It is an annual, self-compatible herb that forms a tumbleweed and has abundant spines on the stems and leaves. In its native range S. rostratum is pollinated by medium- to large-sized bees including bumblebees. The seeds are released when the berries dry and dehisce (split apart) while still attached to the plant (Wikipedia contributors 2019).

This species represents one of the later scientific interests of famed biologist Charles Darwin, who just over a week prior to his death had ordered seeds from a colleague in America, so as to investigate their heteranthery, a topic he was interested in (Wikipedia contributors 2019).

Solanum rostratum is the ancestral host plant of the Colorado potato beetle, Leptinotarsa decemlineata, but this pest adopted the potato, Solanum tuberosum as a new (and more succulent) host, a fact first reported in eastern Nebraska in 1859. It then expanded its range rapidly eastward on potato crops in the next two decades (Wikipedia contributors 2019).

Solanum rostratum as an invasive alien weed

Solanum rostratum is a taprooted annual plant known to be a noxious weed in parts of the USA and Canada, and is included in the Global Compendium of Weeds as an ‘agricultural weed’, ‘casual alien’, ‘environmental weed’, ‘naturalised’, ‘noxious weed’, and ‘weed’ across tropical and temperate regions of the world. It is a fast-growing, vigorous weed native to Mexico and the United States and now widely introduced including into Asia, Oceania and Europe (Austria, Bulgaria, Denmark, Germany, Hungary, Moldova, Russia, Slovakia, UK, Ukraine). The species invades ecosystems by forming dense colonies, and a single plant can produce hundreds of seeds which are dispersed by both biotic and abiotic vectors, as well as self-propelled by its dehiscent fruit (Datiles & Acevedo-Rodríguez 2014).


 Page content last updated on 2019-11-11. Last proofread by Caroline Grounds on 2019-11-11.

Publication of a guide for the identification and management of invasive alien plant species on construction sites

The Luxembourg Nature and Forestry Administration has published a guide on the identification and management of invasive alien plant species on construction sites. The 88-page guide is written in French and can be useful to other concerned parties such as biological stations, municipalities and other state administrations that are active in other activities such as nature sites, the development and maintenance of green spaces and along roads.

The guide can be ordered or downloaded from the following web page:

Citation: Pfeiffenschneider M. et al., 2019. Guide d’identification et de gestion d’espèces de plantes exotiques envahissantes sur les chantiers. 88 pp. Administration de la nature et des forêts (éd.).

 Page content last updated on 2019-11-11. Last proofread by Caroline Grounds on 2019-11-11.