Have you ever walked through a landscape sculpted by centuries of water and wind? Welcome to Wormer- en Jisperveld & Kalverpolder a breathtaking Natura 2000 area near Zaanstad. This vast expanse of low-lying peat bogs and meadows is a testament to the enduring power of nature. Wormer- en Jisperveld & Kalverpolder is a unique ecosystem. It is a haven for diverse flora and fauna.
Imagine the scene in the Roman era. Vast high-moor peat bogs stretched across much of Noord-Holland. Over time starting around 900 AD these bogs were gradually drained. People dug ditches creating a network of waterways. This shaped the landscape into what we see today. These early drainage channels are still visible. The Zwet and the Noorder- and Zuider Gangsloot are prime examples. The drainage caused the peat to subside. By the 12th century the land had sunk to sea level. Small dikes were built to protect the area and the villages. Large lakes like the Beemster and Wormer formed to the north and south.
The water was brackish influenced by the Zuiderzee and the IJ. The Beemster flooded the area frequently depositing layers of clay. Then came the 17th century. The Beemster and the Wijde Wormer were drained and reclaimed. This led to increased flooding. In 1630 the decision was made to dike the entire Wormer- en Jisperveld. This cut off the connection with the Zaan River. The brackish water inflow ceased. The Kalverpolder was also enclosed by a ring dike. Smaller lakes such as the Schaalsmeer and Enge Wormer were drained later.
Brackish water flooding continued occasionally. The last major flood happened in 1916. Soon after the Zuiderzee was closed off. The Afsluitdijk’s construction in 1932 drastically reduced the influence of brackish water. Chloride levels dropped significantly. The water became significantly fresher.
Wormer- en Jisperveld & Kalverpolder is now a sanctuary for wildlife. Reed beds provide habitat for birds such as the bittern and reed warbler. The meadows are vital breeding grounds for many species. The area supports a rich diversity of plants. Rare brackish water species can still be found. There are various types of reedlands including those dominated by the extremely rare bog orchid Hammarbya paludosa. The presence of these orchids highlights the area’s unique ecological character.
The area also hosts several rare species. They include the marsh fritillary butterfly. It’s even a haven for the rare black tern. It’s now only seen in the area. Other notable birds include the ruff which once had 20 pairs breeding. Numbers have been affected by water level management. The area’s history of brackish water and unique land management practices create an incredible habitat.
Wormer- en Jisperveld & Kalverpolder is a place where history and nature intertwine. It’s a place to discover. It is a reminder of the delicate balance between human activity and the environment. Come and explore this remarkable place. Experience its beauty and its rich history firsthand.