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Monitoring of species

The Brussels flora and fauna are subject to scientific monitoring which provides data essential to the development of management policies and measures for biodiversity.  It appears in particular that, despite its urban context and limited size, the Brussels Region is home to a relatively large biodiversity. Although certain groups such as reptiles and butterflies are scarcely represented in relation to the diversity present in Belgium.

Monitoring and follow-up of the flora, fauna, and natural habitats

Since its creation in 1989, Brussels Environment has been tasked with the monitoring and follow-up of biodiversity.  This mission is based on inventories and studies, whose execution is assigned, via public tenders, to universities and research institutions or, via subsidies, to associations for the protection and conservation of nature.

The data collected in this context comply with various objectives which can be summarised as follows:

  • comply with international and Brussels Region obligations in terms of the monitoring of nature and the related reporting (in particular in the context of the Natura 2000 and Birds directives, and the ordinance on nature conservation, etc.);
  • develop and evaluate policies in the area of biodiversity;
  • contribute to highlighting the changes occurring in the environment;
  • inform the public and make them aware of the issues related to biodiversity.

In 2009, with a view to rationalising its various requirements for information and its follow-up initiatives pertaining to biodiversity, Brussels Environment tasked the INBO (Flemish Institute for Nature and Forest) to develop a monitoring strategy for the follow-up of biodiversity in the Brussels-Capital Region (see report by Van Calster H. and Bauwens D., 2010). Furthermore, pursuant to article 15, §1 of the Nature ordinance on the obligations of Brussels Environment in the area of monitoring the conservation status of natural species and habitats, the draft Nature plan includes a measure to develop and implement a five-yearly monitoring schedule.

We can also observe that, since 2009, Brussels Environment has centralised the data it possesses on the species observed in the Brussels Region into one single database. This database represents a key element for Brussels policy in the area of biodiversity.

Inventories of flora and fauna

This sheet pertains specifically to inventories and follow-ups of groups of species carried out at the regional level.  Other monitoring programmes related to biodiversity are however presented in various governing documents of reports on the state of the Brussels environment, in particular those pertaining to biological quality of waterways (see water theme of the present report), to the phytosanitary status of trees in the Sonian forest and to the conservation status of certain species included in annex II of the Habitats directive (see focus on the health status of the Sonian forest and on Stag beetles (Lucanus cervus) of the present report), to natural habitats (see report on the State of the Environment 2007-2010), or even, to the qualitative and quantitative monitoring of green spaces (see documented sheet "Analysis of non-built surfaces in the Brussels-Capital Region by the interpretation of satellite images").

The monitoring of species has resulted in particular in the realisation of several inventories or atlases covering the entire Brussels Region. The table below presents in a highly summarised way the main quantitative data emerging from these studies, namely: the number of species surveyed on the ground during the investigation period (by differentiating indigenous species from species introduced voluntarily or accidentally), as well as the number of species which have become extinct at the Brussels level.  The inventory of species which have become extinct locally is based on historical data (old surveys of flora and fauna, archives, herbaria and insect containers, etc.). The period taken into account, which varies according to the studies, is indicated at the bottom of the table. It should be noted that a new atlas of mammals is currently in progress.

A comparison of these data with an inventory of species drawn up by the Directorate General for statistics and economic information (FPS Economy) shows that around two thirds of the species of mammals and odonates (dragonflies and damselflies) present in Belgium are in the Brussels Region. For the groups for birds, amphibians, orthopterans (crickets and locusts) and vascular plants, this proportion is in the order of 40 to 46%. However it is less than one third for reptiles and diurnal butterflies.

As previously indicated, these inventories ensure compliance with legal reporting obligations.  They also provide information which is vital for developing management policies and measures in the area of biodiversity.  In fact, beyond the figures presented in the table above, these inventories are especially useful by virtue of their resultant analyses, which allow for example:

  • to identify trends in relation to the abundance and spatial distribution of different species, and to highlight the most vulnerable species;
  • to identify the most interesting sites from a biodiversity perspective;
  • to survey the establishment of new species, whether this is due to human intervention or the result of natural processes (e.g. due to climate change);
  • to identify the factors behind the observed changes.

These studies, which are generally information-rich and qualified with respect to their findings, cannot be summarised in a few sentences. For more detailed information, interested readers can refer to the various documents available online (entire publications or summaries, see at the bottom of the page).

Dragonflies and damselflies, bio-indicators of the state of freshwater ecosystems

The last completed inventory of fauna at the Brussels level concerned populations of odonates. This work, produced by a team from the Royal Belgian Institute of Natural Sciences and published in 2013, was not commissioned or co-financed by Brussels Environment, but nonetheless benefited from the use of data contained in the flora and fauna database of Brussels Environment.

The researchers highlighted a very positive evolution of dragonfly populations between the last inventory (published in 2006) and 2013. In fact, at the end of the 20th century, following the disappearance or regression of numerous wetlands, the channelling of waterways and the development of riverbanks, intensive fish farming in water bodies, and even the pollution and eutrophication of waterways, the Brussels Region was home to only 27 species of dragonfly and damselfly. In less than a decade, the status of populations of odonates has vastly improved both in terms of the number of species observed (43 species including 2 never previously observed and other species which are very ecologically demanding which had sometimes disappeared since the end of the 19th century) and their conservation status. According to researchers, this evolution is linked in particular to a general improvement in water quality and riverbank management, the increase in open water (cfr. the Blue Network programme) as well as a reduction in surplus populations of burrowing fish and herbivorous fish. It shows that adaptive management can quickly result in beneficial repercussions in terms of biodiversity.

Date de mise à jour: 06/08/2021



n°2. Oiseaux (.pdf, in French and Dutch only) 

n°3. Les passereaux en forêt de Soignes  (.pdf, in French and Dutch only)

n°4. Les oiseaux exotiques  (.pdf, in French and Dutch only)

n°8. Poissons (.pdf, in French and Dutch only)

n°10. Habitats naturels dans les espaces verts bruxellois (.pdf, in French and Dutch only)

n°11. Lichens épiphytes (.pdf, in French and Dutch only)

n°12. Champignons (.pdf, in French and Dutch only)

n°14. Biodiversité : monitoring des espèces (.pdf, in French and Dutch only)

Theme « L’occupation des sols et les paysages bruxellois »

n°14. Espaces semi-naturels et espaces verts bénéficiant d’un statut de protection (.pdf, in French and Dutch only)

State of the Environment’s sheet(s)

Biological quality of the main waterways and ponds (edition 2011-2014)

Data capture on the Brussels biodiversity by citizens (« crowdsourcing »)  (edition 2011-2014)

Fungi and lichens (edition 2011-2012 )

Habitats naturels dans les espaces verts bruxellois (edition 2007-2010, in French and Dutch only)

Biodiversity: butterflies (.pdf, edition 2007-2008 )

Environnement semi-naturel et espaces verts publics bruxellois : Etat de la flore et de la faune (édition 2003-2006) (.pdf)

Other publications from Brussels Environment

Rapport sur l’état de la nature en Région de Bruxelles-Capitale, 2012 (.pdf, in French and Dutch only)

Study(ies) en reports (in French and/or Dutch only)

Plan(s) and programme(s)

Projet de plan régional nature en Région de Bruxelles-Capitale, 2013 (.pdf, in French and Dutch only)

Biodiversity 2020 – Update of Belgiums National Strategy, 2013 (.pdf)