Schweenssand

Summary

Große Röhrichtflächen prügen das Bild dieser tidebeeinflussten Elblandschaft.

Description

The landscape's defining feature is the branching area of the Elbe, formed by the post-glacial rise in sea level and the subsequent tidal backwater. After the end of the Ice Age, this area became a marshy, aquatic wilderness with extensive floodplain forests. The riparian zone, a remnant of this area, stretches for around four kilometres and up to 400 metres wide on both sides of the Elbe to this day. A wide variety of differently specialised plants have established themselves between the reed beds and the riparian forest. The two nature reserves are generally considered to be among the most species-rich areas in Hamburg, with around 700 species having been recorded here. These include rare plants such as a hair grass species (Deschampsia wibeliana) and Oenanthe conioides. Today, both plants can only be found in the freshwater tidal zone of the Elbe. In areas that flood rarely, marsh marigolds bloom across the low-growing meadows in spring, before being outgrown by reeds in summer. Above the reed beds, reed canary grass sometimes covers large areas of poorer soil, while dense nettle thickets dominate the more nutrient-rich sections. In places where floodplain forests and reed beds were once cultivated across large areas and meadows developed into pastureland, the now rare snake's head fritillary grows. The fauna is just as diverse as the flora and has adapted to the different vegetation zones within the nature reserve. The daily ebb and flow of the tide shapes the vast reed bed habitat. Many species of bird use the impenetrable tangle of reeds as a breeding ground, a place to rest and hide. An army of spiders, beetles, flies, lice, mites and butterflies lives on and in the reeds. This provides the birds with an abundant supply of food. Large birds such as storks and great bitterns come here in search of food. Hidden well in the reeds, the grey heron lies in wait, while the cormorant perches on tree stumps, keeping a sharp watch for prey fish. In winter, titmice, wrens, robins and dunnocks also migrate here to feed.