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Tilburg University and the forest and fens of Oisterwijk
The forest and fens of Oisterwijk is located south of Oisterwijk, a little town near Tilburg in the dutch provence of Noord-Brabant. The area is about 7,5 square kilometers and the natural ponds were formed after the last ice age. It is a nature reserve of outstanding natural beauty. The reserve is owned and kept by the 'Vereniging Natuurmonumenten' (Nature Monuments).
The moorland pools in the region of the SE of Oisterwijk have an established reputation among Dutch hydrobiologists. This fame is to a large extent attributable to the extensive surveys of the desmid flora by Professor J. Heimans in the period between 1916 and 1925. His studies revealed an exceptional opulence of this algal group viz., a total of 250 species among which quite a number not recorded from any other locality in the Netherlands and also to be included among the rarities in a larger geographical region.
The moorland pools are originally oligotrophic, because the soil consists of nutrient poor cover sands. The original vegetation of most pools belongs to theIsoeto-Lobelietum and the consociation ofCarex rostrata andSphagnum.
An inventory of the desmid flora in a number of forest and moorland pools, carried out in 1975, revealed that an appreciable impoverishment has occurred since the turn of the century. In those pools which are immediately surrounded by arable land and pastures or are connected with cultivated areas by small streams, the deterioration is caused by eutrophication and pollution of the aquatic environment. In hydrologically isolated pools, situated within nature reserves, the decline must be attributed to an acidification and oligotrophication of the site. The latter phenomenon may be associated with a much increased acid deposition in the atmospheric precipitation owing to air pollution, as recorded in the Netherlands especially in the last decennia.