Annual report of observations

Annual report of observations: a review of 2021-2022

Why is surveillance important? A quick reminder

The first two years of the LIFE RIPARIAS project were notably devoted to active surveillance of species targeted by the project. The aim of this surveillance is to record and map the geographical distribution of all these species in order to help with the prioritisation of management measures and the development of IAS management plans at river basin level. In order words, no surveillance means no effective management measures.


Platforms for recording observations of IAS in the field: a child’s play

If you encounter an invasive alien species in a pond, along a river or elsewhere in nature, do not hesitate to share your observation on platforms such as ObsIdentify (phone),, iNaturalist or other platforms. New population records will allow us to better map their distribution, to prevent or slow down their spread, and to take early and effective actions.

Do not forget to make sure in your account settings that your observations are shared as "open data" otherwise we won't be able to see them.


The concrete approach and… the results

22 LIFE RIPARIAS target plants were actively searched for in aquatic and riparian habitats, through intensive field surveillance conducted by regional focal points and naturalists within the Dijle-Dyle, Mark-Marcq and Zenne-Senne river basins in 2021 and 2022. This includes 13 plant species listed under EU Regulation No 1143/2014 and 9 plant species from the LIFE RIPARIAS alert list.

The surveillance was organised based on a dedicated plan designed by LIFE RIPARIAS partners focusing mainly on historical sites where target species were observed during the 2000-2020 period and on priority river sub-units.

Thanks to enhanced surveillance, a total of 3663 plant observations were gathered and documented in the invasive alien species databases. This led to a strong increase in IAS annual detection rates and allowed the detection of 18 out of the 22 target plant species, among which 3 alert list species and 2 EU-listed species were detected for the first time within the LIFE RIPARIAS territory.

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Density of observations of target IAS in 2021-2022 across the LIFE RIPARIAS territory. The number of observations collected is proportional to the size of the river basin: 51% of them were collected in the Dijle-Dyle river basin, 42% in the Zenne-Senne river basin and 7% in the Mark-Marcq river basin. Source: LIFE RIPARIAS early alert tool.


Water bodies in private domains were identified as potential hotspots for emerging EU-listed and alert list aquatic species, suggesting that awareness raising of private owners should be a priority for preventive actions.

The data collected during field surveys has played a crucial role in updating species distribution maps. These updated maps serve as valuable tools for identifying management priorities and evaluating the potential impact of future management actions.

The results of crayfish surveillance carried out over 2021-2023 will be addressed in the next review of observations in 2024 and will therefore be available in the next newsletter.

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