Vulnerabilities - Terrestrial biodiversity

In Belgium, as elsewhere in the world, biodiversity losses can be explained by air, water and soil pollution, fragmentation and destruction of habitats, intensive agricultural and forestry practices, exotic invasive species etc. Climate is becoming an increasingly important factor, however, and may be the main source of perturbation in the future (1,3).

During the 21st century climate change will probably result in the disappearance of a part of the species that occur in Belgium. Besides, climate change can also lead to the decoupling of food webs and the break-up of symbiotic relations between species (3).

The arrival of new species adapted to the warmer climate may have adverse effects. Some species will disrupt the structure of existing ecosystems or modify relations between species, in particular due to competition for food or habitat. At the same time, species that are already present in Belgium but only in warmer areas such as buildings and/or cities may spread in the natural environment, where the result may be competition with indigenous species (7).

Seasonal shifts

Shifts of up to 10 days and more were observed in the arrival date of migrating birds in Flanders, although further research is needed to confirm a link with climate change (1,3). Besides it has been shown for several European countries, including Belgium, that the increase in the number of second sittings of parus populations since 1985 is related to the increase of spring temperatures (3).

Forty years of television video footage of the Tour of Flanders (from 1981 to 2016) shows strong spring advancement of the timing of leaf-out and flowering of trees alongside the roads, up to 5 days. This was related to 1.5°C warming in the area since 1980 (8). 

Northward shift

The northward progression of many species from warm regions is noticeable in Belgium. This change is clearly established among certain animal species (molluscs, dragonflies, butterflies, etc.) and certain plant species. Migration will not be possible for all species, particularly those with low mobility, or because landscapes and thus habitats are now highly fragmented (1).

Species that will disappear probably will not do so because they can no longer stand the higher temperatures but because they are outcompeted by other species that are better adapted to higher temperatures (3).

Moorland

The Hautes Fagnes natural reserve provides an example of the combined impacts of climate change and other factors. Peat bogs have been deteriorating for a long time, for a variety of reasons: drying out, pollution and tourism. If this deterioration continues and climate change increases, the most probable scenario is that the last peat bogs that are still almost intact will disappear within the next 20 to 50 years (1,3).

Higher temperatures and lower surface water levels result in increased decomposition. It is doubtful that the productivity of the vegetation will match this increase in decomposition, thus peat accumulation will cease in many areas and the volume of peat will decrease on most sites particularly in low-boreal regions (6).

The Hautes Fagnes natural reserve is an over 670 m high plateau in the east of Belgium. The moorland covers an area of 37 km2 with several rare plant and animal species. The peat bogs with a constant high water table of less than 25 - 40 cm below the surface cover approximately 11 km2, of which less than 1,5 km2 is more or less in its natural state. Climate in the area is relatively cold and rainy (ca 1.400 mm/year, compared with 800 mm/year elsewhere in Belgium).

The Peat bogs have been deteriorating for a long time, for a variety of reasons (3):

• drying out, especially due to a drainage system installed at the beginning of 20th century for forestry, and due to peat excavation;
• pollution, by nitrogen in rainfall mainly (coming from industry and agriculture), by salt for icy roads, and by mineralization of the soil as a result of lower water tables that reduce the accumulation of organic material and increase the number of fires;
• tourism, which at present is restricted.

Climate change will increase the drying out of the peat bogs because of increased evapotranspiration. The moorland will deteriorate and grasses and bush will take over. If the deterioration of the moorlandcannot be stopped, the peat bogs most likely will disappear within the next 20 – 50 years (3).

Vulnerabilities - Fresh water and wetlands biodiversity

A particular case is that of freshwater fish, of which many species could be threatened, but for which a redistribution seems to be taking place through ship canals connecting river catchments (1).

Vulnerabilities - Marine, estuarine and intertidal biodiversity

In the North Sea, the establishment of warm water species is already being observed, and some may compete with local species (1). The change first appeared in the composition of plankton species at the end of the 1980s, with an increase of the relative number of warm water species. More recently, a higher number of warm water fish species such as sardines and anchovy, and a strong decline in the number of cold water species such as cod, shellfish and halibut is being observed (3).

Experts expect the temperature of coastal waters near Belgium to rise by 2⁰C by 2050 (3). So far, however, there are no signs that species have actually disappeared from Belgian coastal water because of climate change (3).

Gradually, the number of species will rise and biodiversity will increase (3). For the Dutch Wadden Sea, for instance, a 20% increase in the number of species is predicted at a 2⁰C increase of water temperature, and an increase up to 30% when temperature rises up to 4⁰C (5).

Adaptation strategies

It is very important to note that biodiversity and healthy ecosystems help to fight against climate change: ecosystems store a very significant quantity of carbon (forests, wetlands, peat bogs, etc.), but they also help to combat the effects of climate change (floods, droughts, soil leaching, natural water purification, etc.). Protecting and restoring biodiversity and ecosystems is therefore an efficient and cost-effective means of combating and adapting to climate change (1).

Measures that enable biodiversity to adapt to climate change can be divided into five groups (2):

• maintenance of genetic diversity at species level;
• further creation of protected areas. Core areas, buffer zones (with partial protection) and migration corridors must facilitate the migration of species following changes in their habitats;
• reduction of all non-climate stresses. As stated above, healthy ecosystems will be more resistant to climate change;
• active and adaptable management. Current knowledge of future climate change impacts is limited. Management needs to be flexible to respond to the real evolution of problems. … For example, this may involve active displacement of species which cannot migrate, as well as control of parasites, diseases and invasive species;
• an assurance that the measures taken to combat climate change will not adversely affect biodiversity.

Policy

In order to preserve biodiversity, Belgium has drawn up a National Biological Diversity Strategy (2006-2016) outlining regional and federal plans to specifically address biological diversity. The Strategy sets out objectives and actions scheduled between the four levels of federal and regional government, while maintaining respect for autonomy and skill sharing. This document also identifies additional areas for action and work to be undertaken jointly in order to safeguard biodiversity (1).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Belgium.

1. Ministry for Social Affairs, Health and Environment (2009)
2. De Bruyn (2005), in: Ministry for Social Affairs, Health and Environment (2009)
3. Van Ypersele and Marbaix (2004)
4. Visser et al. (2003), in: Van Ypersele and Marbaix (2004)
5. De Vooys (1990), in: Van Ypersele and Marbaix (2004)
6. Gignac and Vitt (1994)
7. National Climate Commission Belgium (2010)
8. De Frenne et al. (2018)