A high-alpine flat-bog sanctuary on the slopes above Lake Grimsel in the UNESCO Swiss Alps Jungfrau-Aletsch World Heritage area.
Mederlouwenen Nature Reserve
Mederlouwenen is a small but ecologically significant nature reserve in the Bernese Oberland of Switzerland, sitting on terraced slopes on the northern shore of Lake Grimsel at the head of the Aare valley. Established as a national-level flat-moor protection area within the UNESCO World Heritage property of the Swiss Alps Jungfrau-Aletsch, the reserve protects a 5.3-hectare mosaic of alpine bogs, wet meadows, dwarf-shrub heaths, and rocky outcrops shaped by ancient glaciation.
The site is part of a broader ensemble of protected Grimsel landscapes, including the surrounding "Sunnig Aar" area, where a rare relict Swiss stone pine and larch forest grows on the adjacent mountainside. The name itself, drawn from local Bernese Oberland dialect, reflects the long human history of the terrain: "Meder" refers to hay meadows and "Louwene" to avalanches, both of which shaped how alpine herders once used the sun-warmed terraces above the former Unteraar alp.
Although the visible protected area is modest in size, Mederlouwenen carries national conservation weight because it preserves communities of bog plants, peat-forming mosses, and rare alpine flora, including the long-leaved sundew, that have survived here in the high-mountain setting near the source of the Aare river.
