Marshes, bogs and swamps: habitat fragmentation
Many Dutch marshes, bogs and swamps are so small that the species in them are at risk of dying out.
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Trends
There are almost 1500 marshes, bogs and swamps in the Netherlands, but over 80% of them are smaller than 10 ha (upper figure) and a sizeable proportion of the total area of this habitat is in areas smaller than 100 ha (lower figure).
In the small areas, species are much more at risk of disappearing, especially if the small marsh, bog or swamp is very isolated from other similar areas. Even the largest areas of this habitat (1000 to 5000 ha in size) are too small to be able to guarantee the long-term survival of all the characteristic species in them. However, the effects of habitat fragmentation can be countered by physically linking marshes, bogs and swamps.
Technical note
The upper figure refers to the number of areas of marsh, bog and swamp; the lower figure refers to the total area per area category.
The data are from the LGN3+ database of Alterra. The habitat type has been taken to include reed vegetation and other vegetation of bogs and marshes, with the exception of swamp woodland. The total area of marshes, bogs and swamps considered here is approximately 50% of the total area; open water, waterlogged grassland and similar have been excluded.
Marshes, bogs and swamps less than 50 m apart are considered to be contiguous.
References
- Kalkhoven, J. (1997). Versnippering of overlevingskans van diersoorten in versnipperd landschap. In: Toestand van natuur, bos en landschap. Natuurverkenning 1997. Achtergronddocument 1. IKC Natuurbeheer. Wageningen.
