Non-indigenous species and their invasion risk
Non-indigenous species are often associated with negative impacts on local biodiversity and ecosystem functions. But not all exotic species have a demonstrable impact on other species or habitats in their new environment. For a minority, however, the invasive nature is of such extent that they pose a problem for local biodiversity, the economy or public health, or jeopardise ecosystem services. It is estimated that around 10-15% pose a threat to European biodiversity (cf. Regulation (EU) No 1143/2014). These Invasive Alien Species (IAS) are considered worldwide to be the second most important cause of biodiversity loss (after direct habitat destruction) (Kettunen et al. 2008). It is important for policy to prioritise invasive exotic species, and to implement concrete management measures where urgent and necessary. In this way the management measures and the (limited) resources can be applied optimally. In addition, it is important to continue to use the already existing general preventive measures to avoid harmful consequences of invasive non-indigenous species.
In Belgium, within the context of the 'Alien Alert project', the Harmonia+ protocol was developed in 2014 (D'hondt et al. 2015). This tool provides a first-line risk assessment of potentially invasive alien species, and is also internationally applicable. It stems from a revision of the former Invasive Species Environmental Impact Assessment (ISEIA) protocol (Branquart 2009; Vanderhoeven et al. 2015), which now includes all stages of invasion and different types of impacts. Currently, the Harmonia+ protocol is being revised within the TrIAS project (BELSPO), and is also being made applicable to marine species.
Content and spatial framework
Worldwide, numerous plant and animal species have successfully colonised new habitats, also in the marine environment. The problem of non-indigenous species is not new. In the history books we find reports of early introductions. However, for a number of species it is difficult to say whether they are indigenous or not. For some groups of marine organisms, our knowledge does not extend far into the past. But what influence do non-indigenous species have on their environment? Do they have an impact on humans or the economy? And how can the damage caused by non-indigenous species be reduced?
This website (and accompanying book - Verleye et al. 2020) provides an overview of the 'established' non-indigenous marine and coastal species in the Belgian part of the North Sea and adjacent estuaries (Figure 1). In other words, species that are observed once or only sporadically and that are not believed to be part of an established population or whose reproduction is prevented by unsuitable biotic or abiotic environmental factors are not taken into account here.
Figure 1: Overview of the study area, i.e. the Belgian part of the North Sea and adjacent estuaries.
We strive to keep the list of species as up-to-date and complete as possible. This is not easy, as non-indigenous species are often discovered by accident and some species groups are less well known, such as plankton. In addition, non-indigenous species can sometimes be difficult to distinguish from local species, which can lead to the erroneous naming of a non-indigenous species.
Which species can be found on our website?
- all known non-indigenous species with established populations in saline and brackish environments along the Belgian coast, the Belgian part of the North Sea, the Ostend Spuikom or the Scheldt estuary.
- if there is a suspicion that a cryptogenic species has been introduced, it is also added to the list
- species introduced by man, intentionally or unintentionally.
Which species will NOT be found on our website:
- foreign species that have been spotted along our coast, but of which we are not sure whether they have established themselves permanently (vagrants)
- species that only occur in freshwater
- species that have found their way to the Belgian coastal waters through natural dispersal
This platform offers the possibility to consult comprehensive information on the life cycle and ecology of the species, the methods of introduction and spread, potential effects or measurable impact of the species on the environment and possible measures. Please note that because for some species there is still some uncertainty regarding the exact area of origin or vector of introduction, a single species is sometimes attributed to several 'potential' areas or vectors. Please therefore exercise caution before drawing any conclusions and always consult the extensive species page and associated sources for further information. In addition to the species-related information, an overview is provided of the national and international policy context with regard to non-indigenous species.
Species that are only sporadically observed (of which the establishment has not yet been scientifically proven) or that have not yet been found in Belgium, but have been found in the nearby waters of our neighbouring countries, are kept up to date by the VLIZ in a so-called 'Watchlist'. The list mainly includes molluscs (American oyster drill Urosalpinx cinerea, brackish water corbula Potamocorbula amurensis, striped conehead Simnia patula, Japanese oyster drill Ocinebrellus inornata and Mulinia lateralis) and arthropods (brown shrimp Penaeus aztecus, angular crab Goneplax rhomboides and the crab Grandidierella japonica). In addition, a moss creature (Bugula neritina), a fish (Gobiosoma bosc) and a worm (tube worm Bispira polyomma) are also on the list. The evolution of these species is monitored together with the VLIZ Alien Species Consortium.
VLIZ Alien Species Consortium
The scientific information made available on this website originates from the VLIZ Alien Species Consortium, a cooperation between VLIZ and scientists from various national and international knowledge institutes. The experts listed below (25), working within 14 different institutions and coming from 4 different countries, have contributed to the updating of the species information (2019-2020) (see also Verleye et al. 2020):
|
Name |
Institute |
Country |
| Azémar Frédéric |
(ECOLAB) Université Paul Sabatier - Laboratoire Ecologie Fonctionnelle et Environnement |
FR |
|
Backeljau Thierry |
(RBINS) Royal Belgian Institute of Natural Sciences |
BEL |
|
Belpaire Claude |
(INBO) Flemish Research Institute for Nature and Forest |
BEL |
|
Boets Pieter |
(PCM) Province of East Flanders - Provinciaal Centrum voor Milieuonderzoek |
BEL |
|
De Blauwe Hans |
(SWG) De Strandwerkgroep België |
BEL |
|
De Clerck Olivier |
(UGent) Ghent University - research group Phycology |
BEL |
|
De Grave Sammy |
(OUMNH) Oxford University Museum of Natural History |
UK |
| de Voogd Nicole |
Leiden University / Naturalis Biodiversity Center |
NL |
|
Delbare Daan |
(ILVO) Flemish Research Institute for Agriculture, Fisheries and Food |
BEL |
|
d'Udekem d'Acoz Cédric |
(RBINS) Royal Belgian Institute of Natural Sciences |
BEL |
|
Faasse Marco |
(eCOAST) eCOAST Marine Research |
NL |
|
Gittenberger Arjan |
GiMaRIS |
NL |
|
Kerckhof Francis |
(RBINS) Royal Belgian Institute of Natural Sciences |
BEL |
| Provoost Sam | (INBO) Flemish Research Institute for Nature and Forest |
BEL |
|
Rumes Bob |
(RBINS) Royal Belgian Institute of Natural Sciences |
BEL |
|
Sabbe Koen |
(UGent) Ghent University - Laboratory of Protistology and Aquatic Ecology |
BEL |
|
Soors Jan |
(INBO) Flemish Research Institute for Nature and Forest |
BEL |
|
Speybroeck Jeroen |
(INBO) Flemish Research Institute for Nature and Forest |
BEL |
|
Tackx Micky |
(ECOLAB) Université Paul Sabatier - Laboratoire Ecologie Fonctionnelle et Environnement |
FR |
| van der Loos Luna |
(UGent) Ghent University - research group Phycology |
BEL |
|
Van Landuyt Wouter |
(INBO) Flemish Research Institute for Nature and Forest |
BEL |
|
van Moorsel Godfried |
Ecosub |
NL |
|
Van Steenbrugge Lies |
(ILVO) Flemish Research Institute for Agriculture, Fisheries and Food |
BEL |
|
Verreycken Hugo |
(INBO) Flemish Research Institute for Nature and Forest |
BEL |
|
Volckaert Filip |
(KU Leuven) Katholieke Universiteit Leuven - Ecology, Evolution and Biodiversity Conservation |
BEL |
Definitions
Non-indigenous species (exotic): An exotic species is an organism that has established itself outside its native range in an area where it does not occur naturally.
Invasive species: If a non-indigenous species proves to be harmful to its new habitat or to the local economy, it is called an invasive species.
Cryptogenic species: For some species it is difficult to say whether they are indigenous or not. This doubt may arise in the case of cosmopolitan organisms and in the case of species that were not well known in the past because the techniques used at the time were not sufficiently developed to study them. Such species are called 'cryptogenic'.
Wanderer: A wanderer is a species that is observed once (or several times) in a 'new' area (outside its natural habitat), where it has no established populations.
Primary introduction: The primary introduction refers to the human activity that introduces a non-indigenous species directly from its area of origin. Secondary dispersal refers to the subsequent further expansion within the new area.
Baseline: A baseline is an arbitrarily chosen point in time. The purpose of a baseline is to compare the situation before and after the baseline or to clearly distinguish between two periods.
Natural colonisation: New animals and plants, but also fungi and bacteria, can arrive in the Belgian coastal waters by natural dispersal, e.g. drifting along on a piece of wreckage. Species can also expand their habitat or area naturally.
Anthropogenic introduction: Usually non-indigenous species are introduced by man, either intentionally or unintentionally. Examples include species that are transported by ships (in ballast water or attached to the hull) or species that are imported along with exotic animals for aquaculture purposes.