[Invasive-species] a question about Crassula helmsii, an invasive waterplant species in Western Europe

[Mathieu Halford]

Dear Steven,

Indeed the control of Crassula Helmsii is very 
hard and almost impossible for big populations. 
Total control will always disturb the whole 
aquatic ecosystem with no guarantee that the 
species will never re-establish. Eradication 
(with limited collateral damages on the 
ecosystem) seems only possible for small 
populations through repeated manual removing 
during several years. This underlines the importance of early detection.

In Belgium a management guide is available on 
http://www.gembloux.ulg.ac.be/biodiversite-et-paysage/telechargements/
Sorry it is in French. You will find general 
guidelines about the management of C. Helmsii, 
with study cases at the end of the document.

Kind regards
Mathieu Halford, AlterIAS project coordinator
Website: www.alterias.be

At 07:44 17/10/2012, Richard Lansdown wrote:
>Content-Type: 
>multipart/alternative;    boundary="----=_NextPart_000_0010_01CDAC32.D0EAE650"
>Content-Language: en-gb
>
>Dear Steven,
>
>It is my belief that in the UK no method has 
>been found to control this species successfully; 
>even in the most successful cases, control of C. 
>helmsii has required the eradication of all plants in a wetland.
>
>I would be very interested to hear of successful control.
>Best wishes
>Richard
>
>-------------------------------------------------------
>Richard Lansdown
>Chair IUCN/SSC Freshwater Plant Specialist Group
>Ardeola Environmental Services
>45 The Bridle
>Stroud
>Glos. GL5 4SQ
>Tel: 01453 763348
>Mob: 07802196494
>
>From: invasive-species-bounces at biodiversity.be 
>[mailto:invasive-species-bounces at biodiversity.be] On Behalf Of Steven Keteleer
>Sent: 16 October 2012 22:33
>To: invasieve soorten mailinglijst; invasive-species-owner at biodiversity.be
>Subject: [Invasive-species] a question about 
>Crassula helmsii, an invasive waterplant species in Western Europe
>
>Dear members of this mailing list,
>
>I've been asked to get information about the 
>most effective combats against Crassula helmsii. 
>This species is now widely scaterred in Flanders 
>and before that elsewhere in Western Europe.
>
>Is there anyone between you who knows a way to 
>fight this invasive waterplant effectively?
>
>I should like to know about cases in other 
>countries than Belgium and Flanders where 
>methods of combats against this species are 
>proven to be effective and efficiënt.
>Particullarly important to us is the 
>effectiveness over the longer term. Thus, which 
>methods are proven to make this species disappear for a longer period?
>Of course methods without the use of poison are of most interest.
>
>Answers may be send to my private email but may also be shared over this list.
>
>Kind regards,
>
>Steven Keteleer
>
>
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>Invasive-species at biodiversity.be
>http://mailman.biodiversity.be/mailman/listinfo/invasive-species

-------------------------------------------------------------------------------------------------------------------
Ing. M. Halford
Unité Biodiversité & Paysage / Biodiversity & Landscape Unit
Département Forêts, Nature et Paysage / Forest, Nature and Landscape Department

Université de Liège
Gembloux Agro-Bio Tech (GxABT)
Passage des Déportés, 2
5030 Gembloux
Belgique
Tél. : 081/62.23.89
Fax : 081/61.48.17
Mail : mhalford at ulg.ac.be  
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