And heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.
Auguries of Innocence - by William Blake (1757-1827)
Huis ter Heide estate lies between the villages of De Moer and Loon op Zand in the Province of Brabant, northwest of Tilburg City in the Netherlands. It's an attractive nature reserve with ponds, lakes, moorland, agricultural fields and forests. Huis ter Heide was therefore the location of the fieldtrip of June 8th 2011 for the Dutch Desmid working group. We started sampling the northern boundaries of Lake Leikeven. The landscape of Leikeven is characterized by low growing vegetation on acidic soils.
|My colleague Wim and I are sampling the first|
location at the Northern side of Leikeven.
Photograph: Ruud Janissen/Aquon
Lake Leikeven was originally a landscape of peat and extensive bogs. At some locations, the peat layer was several metres thick. Peat was very useful as fuel and was therefore excavated between 1200 and 1600. After the peat was excavated and exploited, a new landscape was formed: Leikeven became a moorland lake, just like Plakkeven, also a part of Huis ter Heide estate. The water of the lakes was very pure, resulting in the ultimate survival of very rare and almost extinct species of animals and plants, like water lobelia.
|South of Leikeven|
After the peat excavation during the Middle Ages, the people of Brabant decided to use the land for agricultural purposes. They were not all that lucky: part of the Southern fields were troublesome due to drainage problems. The South transformed to wet heathlands, while forests for wood production were submitted to the landscape. Meanwhile, intensive farming lead to other complications.
Manures were washed away into the lakes, creating a thick layer of silt on the bottom of the lakes. Pollution became a real threat to the rare species existing at Huis ter Heide nature reserve. Interventions were therefore necessary to reverse the damage and to create new opportunities for rare species. The nature organization Natuurmonumenten worked for more than 18 years on Plan Lobelia, to restore Huis ter Heide to a more natural state.
|Lobelia dortmanna (Water Lobelia) is a|
rarely seen aquatic plant. I didn't
take my macrolens with me,
so I had to do with a landscape picture
Since then, the water quality of lakes like Leikeven has been greatly improved by interventions like excavating, clearing and cleaning. The result is that more desmids get a real chance for survival: after restoring the lakes, desmids tend to recover in a spectacular way. Besides, spores of desmids are able to overcome dehydration and general deterioration of water quality, to some extent. They also get help from animals: waterbirds and insects transport spores to better locations for germination.
And even plants like the very rare water lobelia, which once flourished abundantly, are back at Huis ter Heide nature reserve. Sundew and marsh gentian germinate in the nutrient-rich soil.
We did see that sundew were in abundance around Lake Leikeven during the fieldtrip. Equipped with rubber boots, sample tubes and a plankton net, we took various samples of Leikeven at different locations to discover the richness of the site. We got some instructions from other members of the Desmid working group how to extract the best of water plants like bladderworts for quality samples, possibly containing desmids.
|We saw various species of green grasshoppers, small |
a while ago in Tilburg (not at Huis ter Heide).