Samstag, 2. Juni 2012

Field Trip to the Rhine on May 25th, 2012

Last Week, I made a little field trip to the riverbanks of the Rhine in my home town of Düsseldorf in Western Germany.

1) Introduction

The Tour starts in the urban district of Bilk at the bottom of the famous “Rheinturm”(Rhine Tower), which is a characteristic feature of the Düsseldorfer Skyline. Then, I followed the arc-shaped shoreline until I reached the railway bridge in the urban district of Hamm, where my field trip ended.

Rhine at Düsseldorf, Germany

The whole area is also known as Rheinknie in Germany (“Rhine knee”; the name refers to the bendings of the Rhine in this area). All in all, I walked a distance of nearly 4,78 kilometres.

"Hammer Eisenbahnbrücke" (railway bridge) - left side: old
bridge towers from 1970 (bridge blown up by the Wehrmacht on March 1st, 1945)
right side: new bridge, built in 1984 and opened in 1987)

It was more an unspecific field trip, so I hadn't the intention to find some special types of vegetation or rare species. The only “goal” was to walk through the area and to look, what grows here.

2) Area

All in all, the area can be divided into four parts: the riparian forest, the rocky beach, the embankment and last but not least the meadow

a) Riparian forest

Riparian forrest at Düsseldorf City Harbour

In the riparian forest (“Auwald” in German), my field trip started. It grows on a very narrow promontory in the city harbour of Düsseldorf. It's probably a pioneer forest because the “soil” was in fact a mix of rocks and stones. I suspect, that this was a former quay, which was later overgrown by the nature.

So, the forest is also some type of ruderal wasteland in an advanced stage of succession. A lot of plants grow in gaps between the stones or on the poor developed soil. However, because of the proximity of the river, the area is also very wet and sometimes flooded..

Some species, which I found here, were Salix alba L., Solanum dulcamara L., Iris pseudacorus,L. Rumex acetosa L., Carex spicata Huds., Anagallis arvensis L. and Potentilla anserina L.

b) Beach

Rhine shore at Düsseldorf - Rocky Beach

After leaving the riparian forest, I reached the beaches. They are a very popular destination for swimming, basking and barbecue. Because of the sunny day, there were indeed many people at the beach.

The beach can divided into two types: a sandy beach and a rocky beach. The last one is more natural, while the first one was created for the people. In both cases, the soil isn't very deep and often flooded by water. Sands and rocks are not a very good nutrient storage, so the plants gets them mostly from the water.

Rhine shore at Düsseldorf - sandy beach

Beside many, stranded mussels, some plants in this sub-area were Silene latifolia Mill., Euphporbia esula L., Cerastium tomentosum L. (which is a neophyte), Potentilla reptans L. and Stachys sylvatica L.

(c) Embankment

Rhine shore at Düsseldorf - Embankment

These are anthropogenic, rocky slopes, which were created to elevate the land a little bit about river-level or to mark the low water area for ships. They are in direct contact to the river and often flooded. On embankments, you often found some exotics species, because their seeds stranded here and germinated in the gaps between the rocks.

Some species in this area were Ficus carica L. and Carex nigra L.

d) Meadow

Rhine shore at Düsseldorf -meadow at the bridge

The meadow has no direct contact to the river and is elevated by the embankment some metres about river-level. So, this area (especially the soil) isn't so often flooded than the areas before. Unfortunately, I cannot exactly say, which type of meadow it was, but I suggest, it was a wet meadow, which became a pasture and later a ruderal meadow. So, it's probably a typical oat-grass meadow. (Arrhenatherion elatioris)

Species in this sub-area were Lotus corniculatus L., Carex hirta L., Veronica teucrium L., Galium album Mill. and of course Arrhenatherum elatius (L.) P.Beauv. ex J.Presl & K.Presl

3) Species

4) Pictures

a) Riparian forrest

Allie schoenoprasum L.

Anagallis arvensis L.

Carex spicata L.

Salix alba L.

 Sedum album L.

Sisymbrium altissimum L.

Symphytum officinale agg.

Symphytum bohemicum Schmidt. 

Potentilla anserina L.

Oxalis fontana Bunge.

Iris pseudacorus L.

Vicia villosa agg.

Galium album Mill.

 b) Beaches

Cerastium  tomentosum L. - habitus

Euphorbia esula L.

Potentilla reptans L.

Silene latifolia L.

Stachys sylvatica L.

c) Enbankments

Carex nigra L.

Caloplaca citrina (Hoffm.) H. Olivier & Lecanora murals (Schraeb.) Rabenh.

Ficus carica L.

Grimmia pulvinata Hedw. & Sm.

d) Meadow

Ailanthus altissima (Mill.) Swingle.

Carex hirta L.

Lotus corniculatus L.

Rumex acetosa L.

Trifolium pratense L.
Veronica teucrium L.

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