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LIFE RIPARIAS Newsletter 01

A European and Belgian initiative for fighting Invasive Alien Species (IAS) and protecting critically important ecosystems

LIFE RIPARIAS, what is it? Reaching Integrated and Prompt Action in Response to Invasive Alien Species. These are the key words behind this new project funded by the LIFE Programme of the European Union and the three regional authorities of Belgium. LIFE RIPARIAS develops innovative approaches that will improve the detection of IAS and help setting priorities regarding where and how to manage them across regional borders.

IAS in the spotlight. The project targets several problematic invasive plants and crayfish that are listed as IAS of EU concern in the EU Regulation No 1143/2014. These species threaten aquatic and riparian habitats, which are of great conservation value but are also considered as ‘invasion hotspots’ as they host a high number of IAS.

Water primrose (Ludwigia grandiflora). © E. Branquart

Highlights on the pilot areas. LIFE RIPARIAS tests its innovative approach in the Dijle, Mark and Zenne river basins of the Scheldt river basin district, a pilot area covering 263.103.000 ha across the three regions of Belgium.

Meet LIFE RIPARIAS partners! LIFE RIPARIAS is not only about fighting IAS! It is also about the collaboration between 11 organisations across Belgium ranging from public bodies, academia and associations, all committed to tackle this challenge!

You want to get involved? Learn more about the project on our website and how you can get involved in IAS surveillance and management! Trainings and dedicated events will be organised for professionals and citizens. There will also be volunteering opportunities!

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The enhanced surveillance of IAS has started!

The first two years of the LIFE RIPARIAS project are notably devoted to active surveillance of aquatic plants, riparian plants and crayfish species targeted by the project. The aim of this surveillance is to record and map the geographical distribution of all these species. This will help to prioritise management measures and to develop IAS management plans at river basin level.

Le Service Public de Wallonie et les Contrats de Rivière supervised the design of a surveillance plan that standardises the collection of information in the field for the three regions of Belgium. The status of IAS populations formerly found in water bodies, rivers and riparian areas will be updated and sites insufficiently monitored so far will be surveyed. Enhanced surveillance efforts will be carried out in hydrological sub-basins of high conservation value (e.g., Natura 2000 sites).

The LIFE RIPARIAS teams began surveillance actions in early April by revisiting populations of giant hogweed in order to establish their exact location. Enhanced surveillance for other species targeted by the project will start in early June.

Giant hogweed (Heracleum mantegazzianum). © E. Branquart

The art of trapping: choosing the right traps

In April 2021, Brussels Environment started using crayfish traps to map the presence of invasive alien crayfish found in Brussels' ponds and waterways. Six crayfish species occur in Belgium, of which only one is indigenous.

To determine which traps provide the best catch results, several crayfish traps were set in different ponds in Brussels where crayfish have been detected. The selected traps will be used during LIFE RIPARIAS surveillance campaign.

While some of the five invasive crayfish species are already present in the project area, others, for which vigilance is needed, are still absent. Indeed, through the LIFE RIPARIAS project, special attention is paid to invasive species that are in the process of being introduced or have recently been observed for the first time in Belgium. An example of such a species is the marble crayfish Procambarus virginalis, which has already been found in the wild in a few places in Belgium, but fortunately has not yet been observed in the LIFE RIPARIAS project area. This invasive species is special because it is the only crayfish in the world that can exclusively reproduce asexually. All individuals in a population are therefore females and the unfertilised eggs they produce will develop into natural genetic clones of their mother. Due to their potential for rapid reproduction, these crayfish pose a great potential threat to indigenous biodiversity. It is therefore important to detect them quickly and take appropriate management measures to prevent their establishment and further spread.

Marbled crayfish (Procambarus virginalis). © X. Vermeersch

Eradication to fight extinction: the case of the red swamp crayfish

The red swamp crayfish (Procambarus clarkii) has been established in Belgium since 1996 and is now slowly spreading throughout the country. It has recently been detected in several sites in the LIFE RIPARIAS project areas. This emerging crayfish species is on the list of invasive alien species of Union concern. Indeed, its impact is particularly deleterious on aquatic plants, amphibians and fish as well as on aquatic environments (weakening of banks, etc.).

Thousands of red swamp crayfish were detected in 2019 in an isolated pond in the town of Grez-Doiceau. Funding from the LIFE programme made it possible to initiate a local eradication operation for this population, under the supervision of the Service Public et des Contrats de Rivière de Wallonie.

The eradication action consisted in emptying the colonized pond (after rescuing the fish) and keeping it dry for a period of two years, in agreement with the pond owner. In order to avoid the dispersal of the crayfish, a semi-buried barrier was installed all around the pond and a grid was placed on the evacuation monk. Post-management monitoring will be carried out using traps after re-filling the pond to ensure the success of the eradication project.

Placement of a semi-buried barrier. © G. Henrard

Networking workshop: spreading knowledge to stop the spread of IAS

On the 24^th of March 2021, LIFE RIPARIAS project partners organised a one-day international workshop to which experts from other EU-funded projects on IAS participated.

The objective of the workshop was to exchange experiences and practices on IAS management. Sharing knowledge is essential for the LIFE RIPARIAS team to make the most of past and present experience, identify limitations, successful elements and technical considerations. This will help LIFE RIPARIAS to develop its decision support tool for IAS management at the scale of a river basin.

During the workshop, experts and partners discussed about the importance of prioritisation for IAS successful management. Together, they identified essential criteria to consider for each of these questions:
- How to prioritise areas and species to be managed?
- How to choose the most appropriate management techniques?

As IAS spread beyond geographical borders, fighting those species requires collaboration between countries. LIFE RIPARIAS will, therefore, promote the replication of the approach developed as part of the project throughout Europe. This will thus contribute to the EU-wide implementation of EU Regulation No. 1143/2014 on the prevention and management of IAS.

The LIFE RIPARIAS project has received funding from the LIFE programme of the European Union.