workPosted by Rense Sep 11, 2010 20:45:47
About two months ago, ecologists of Alterra (Wageningen University and Research) discovered Small capsule dung moss (Splachnum ampullaceum
) at the 'Witterveld', a military training area in the vicinity of Assen, NL. This moss species was considered extinct from the Netherlands, where it was found only 5 times, for the last time in 1905. It grows on old old cow dung in bogs. These systems are very rare, because of land reclamations in the 19th and 20th century. The few remaining bogs are not grazed.
The Witterveld is grazed by 'Blondes d'Aquitaines' for management reasons: they keep the heathland open and free from trees. Now they have another effect: they made it possible for the dung moss to grow. At the Witterveld, Small capsule dung moss is found at only one excrement, and it had no capsules.
Here's a photo of the moss. It isn't spectacular in appearance, but the occurrence of this Small capsule dung moss in the Witterveld is quite puzzling. How did it reach this area? Are there more locations in the vicinity where it grows? Is it overlooked, or did it reach the Witterveld from far? No one knows. But it's worth to keep the eyes open, for mosses growing on cow dung....
Small capsule dung moss, September 2010, Witterveld
workPosted by Rense Aug 29, 2010 15:31:56
Friday, Iris de Ronde and I went to the 'Mantingerbos' in the heart of Drenthe. This is a old woodland remnant along the 'Oude Diep', a small lowland rivulet, characterised by old, more than 10 meters high holly trees (Ilex aquifolium
). The history of this woodland dates back to prehistoric times, and it's the only woodland in the Netherlands from which we know it has been permanently wooded from prehistory till present. This doesn't mean there are no - old and recent - human influences recognisable. In Medieval times, trees were cut, and later the Mantingerbos was grazed. Due to this grazing, holly could take over large areas.
The Mantingerbos is the place where I was confronted with bramble diversity for the first time. I did a vegetation mapping project for the 'Vereniging Natuurmonumentn', the owner and manager of the forest. My supervisor, Piet A. Bakker pointed out the Rubi
of the area, and said: "You could try to include the brambles too..." I was hooked! The bramble flora of the Mantingerbos is quite special, with several characteristic old woodland species, like Rubus pedemontanus
and R. arhenii
. Rubus mucronulatus
has one of it's few occurrences in our country in the road verge thickets here, which are mainly formed by R. idaeus
(Raspberry) and R. glandithyrsos
. The Mantingerbos is designated as one of the Natura 2000 sites in our country.
We made photos for the Rubus
website of all the main species growing here, including the ones named above. You can find them on my website: Rubus species in The Netherlands
. The species in bold font can be viewed in a separate window. Below you will find some photos to give you an idea about the Mantingerbos.
Rubus thickets in the road verges near the Mantingerbos
Holly woodland with Dryopteris in the field layer
Holly woodland in the Mantingerbos
workPosted by Rense Aug 14, 2010 11:21:36
Yesterday, I added a comprehensive list of Dutch Rubus
species on my website. Rubus
has it's European centre of diversity in the lowlands in western Europe, and in our country, about 200 species can be found. Although the Dutch Rubus
flora is very well known, until now there was no overview of all native and introduced taxa. The published list is made by prof. A. van de Beek, and together with him, R.J. Bijlsma and I will publish a official check list later this year or next year. On my website, I will add photos of as much species as possible.
As said, the Rubus
flora of The Netherlands is very well known, but there are still discoveries to be done. Last week, while working on my Rubus
transects with my colleague Iris de Ronde (see one of my earlier posts), we found an unknown Rubus
species near Maarn, which was identified later as R. euryanthemus.
This taxon was not known from The Netherlands before. It's known distribution includes England and Wales, Sleswig-Holstein and Niedersachsen in Germany, and some solitary founds in Denmark and Belgium. Our plant forms a nice connection between the British and the German distribution areas.
species list can be found here
, and of course you will find photos of Rubus euryanthemus
workPosted by Rense Jan 18, 2010 22:19:04
Today I worked in the Dutch National Herbarium in Leiden. Together with Iris, a colleague of mine, I did some research on hawkweed (Hieracium
) species that were described from the Netherlands. To link a name to a certain species, botanical rules ask that every species is defined by a type specimen. And most of the species that were described for the Netherlands were never typified, so no type specimens were designated. Which herbarium specimens are suitable to serve as type specimens is bound to strict rules (again). Our job today was to find good type specimens for some of those species.
And of course I brought my Pentax camera with me, with the A 50mm/F1.7 mounted. It served well, because I was perfectly able to make good photos of some herbarium sheets. The picture below shows the type specimen of Hieracium bifidum
L. ssp. jansenii
Zahn, which was found only once in the Netherlands, and which is only known of this single collection. It has to be considered extinct, because after it's first discovery in 1912, it was never seen again ...
workPosted by Rense Oct 25, 2009 12:52:22
At the northern hemisphere it's autumn. After a summer of production, nature is preparing for a resting period, at least in the temperate zone. This is accompanied by magnificent colours, in which red and yellow are the most important tones. But did you ever wonder why European trees colour yellow in autumn, and the predominant colour in Northern America is red? Well, I did. But I never got an answer. Until last week, when I asked this same question on a forum of Pentax-users. And there I was redirected to the site of Science Daily. It has to do with the long gone era of the ice ages. Want to know more? Go here
workPosted by Rense Oct 16, 2009 14:43:57
Last two weeks I have been quite busy with a second "Bramble Transect". Last year, I sampled bramble vegetation along a 100 km transect through the Dutch provinces of Overijssel, Drenthe and Frieland, and last week I started a similar transect through the province of N-Brabant. This research is part of my PhD project. What I want to figure out is the relation between the regional bramble diversity and the bramble diversity in bramble scrubs. It's quite hard labour, but it's fun also! Up to now, I found about 17 of the 200-something Dutch bramble species in this second bramble transect. In the photos two of the more common species: Rubus plicatus (the frozen one), and Rubus nessensis.
Apart from making vegetation descriptions, I make shadow profiles from every scrub. This is quite easy with a so-called 'horizontoscope'. I use the one called 'Solar Pathfinder'. This is me, struggling with the apparatus....
workPosted by Rense Oct 16, 2009 14:00:51
After seeing many examples of blogs of persons I know and don't know, I decided to make one myself. Why? Well, it's just a way of accepted exhibitionism, I guess. Although it feels as if nobody is looking. The World Wide Web is such an anonymous place, and I feel save to share my life with you, from whom I don't know who and where you are, what you do for a living or exist at all. We will see how this thing develops, and whether I will find things to share at all.
I hope I will have a good time here!