Ever imagined a haven where biodiversity thrives? That’s Wollmatinger Ried – Untersee – Gnadensee. It is the largest and most important nature reserve on the German side of Lake Constance. Prepare to be amazed by its rich plant and animal life.
Wollmatinger Ried covers 767 hectares. It stretches from the Seerhein river near Constance to the Island of Reichenau. The reserve also includes the Gnadensee near Allensbach-Hegne. Even the islands of Triboldingerbohl and Langbohl belong to it.
This area gained initial protection in 1930. Then in 1938 it was officially designated a nature reserve. The protected area initially covered 465 hectares. Later expansions included the Untersee and Gnadensee. This increased the area to its current 767 hectares.
The diverse landscape hosts valuable habitats for plants and animals. Around 600 fern and flowering plant species exist here. Almost 290 bird species have been spotted too. Wollmatinger Ried serves as a crucial breeding ground and resting spot. Migratory birds find refuge here. In autumn 20000 to 40000 waterfowl gather. The shallow water zones help maintain a rich fish population. Insects also flourish with over 330 butterfly species. Dragonflies and grasshoppers add to the vibrant insect life.
Wollmatinger Ried’s importance has earned it international recognition. In 1968 it received the European Diploma for Protected Areas. Since then it has been renewed every five years. In 1973 the International Council for Bird Preservation declared it a European reserve. Since 1976 this area is a wetland of international importance under the Ramsar Convention. Wollmatinger Ried is part of the Natura 2000 network. This system protects significant natural sites in Europe.
The Untersee landscape has a fascinating geological history. It involves tectonic shifts and sedimentation. During the Alpine formation the northern Alpine foothills formed a large basin. This basin was filled with both seawater and freshwater. Large amounts of eroded material from the Alps washed into it. During the ice ages the Rhine glacier deepened the Lake Constance basin. After the ice melted moraine material was eroded. This left behind substantial clay deposits in the lake area.
Unique sediments exist near Seerhein, Untersee, and Wollmatinger Ried. These are lime nodules formed by blue-green algae. These nodules often form around snail shells. Locals have long called them Schnegglisande.
Lake Constance’s water level varies with the seasons. The main inflow from the Alpine Rhine causes these fluctuations. The lowest water levels usually occur in February. Then the water rises with snowmelt in the Alps. Peak levels are reached in June and July. Sometimes heavy rains and snowmelt cause rapid rises.
Wollmatinger Ried has minimal elevation differences. It lies in the Konstanz depression. This flat basin sits between the Bodanrück hills and the Thurgau ridge. Areas near the lake flood regularly in early summer. In extreme years over 90% of the reserve can be underwater. In winter the Ried and shore zone dry out. This can last into the summer in dry years. These water level changes greatly influence the area’s plant and animal life. They also impact how humans use the land.
Frequent flooding allows only limited farming. This creates a mix of natural and cultivated landscapes. Natural habitats include shallow water zones and reed beds. Farmers created meadows through agricultural use.
The Seerhein River flows into the Untersee at Wollmatinger Ried. The reserve borders the river on its southeastern side. The Seerhein’s main channel continues westward. The river’s fish attract birds. These include divers, cormorants and terns. During winter ducks feed on the riverbed.
Two branches of the Seerhein flow within the reserve. These channels separate reed-covered islands. Triboldingerbohl and Mittler or Langbohl are separated from Wollmatinger Ried. These channels provide breeding sites for endangered terns. Ditches in the reed zone offer winter habitats.
Since 1980 parts of the shallow water zones have been protected. These zones connect the lake shore to open water. They are warmer in summer. Water movement ensures oxygen and nutrient exchange. Aquatic plants thrive here. They provide spawning grounds for fish and food for waterfowl.
Two key shallow water areas exist near Wollmatinger Ried. The Ermatinger Basin is a flood area. It lies at the mouth of the Seerhein. Hegne Bay sits east of the Reichenau causeway.
These shallow waters host many bird species. These include grebes, swans, ducks and gulls. Wading birds also visit during low water. The Hegne Bay often freezes in winter.
In conclusion Wollmatinger Ried is a dynamic and vital habitat. It supports countless species and offers a glimpse into the natural history.