The nature reserve "Small Lake and Adjacent Salt Marshes" on the Baltic Sea has a size of 255 hectares and includes the Small Lake, adjacent salt and marsh meadows in the dyke foreland and the upstream beach section with beach, wall and dunes. The beach wall separates the salt marshes from the beach. Chickweed, stonecrop, saltweed, sea holly and sea kale grow on the beach. The beach wall is overgrown with various grasses, beach grass and beach rye. A belt of rushes and reeds lies to the southeast between the path and the lake shore. There used to be a natural connection between the inland lake and the Baltic Sea. In addition to rushes, reeds and sedges, marsh horsetail, pine fronds, water buttercups and cuckoo flower grow in the many damp depressions. Spotted orchid can also be found in some places. This is also the habitat of sand and mountain lizards. Grass snakes are quite common in sunny spots throughout the area.
In the beach lakes, sporadically penetrating Baltic Sea water mixes with fresh water flowing in from the hinterland to form brackish water. The Kleiner Binnensee lies on one of the main bird migration routes over the Baltic Sea. In summer, waders use the mudflats to forage. Numerous white-cheeked, barnacle and bean geese, which are native to the tundra and arctic, overwinter from autumn to spring.
The Baltic Coast Cycle Route runs through the nature reserve, from where you can see large parts of the landscape. Starting at the Yellow Gate car park on the beach, it leads to the Lippe harbor. Halfway there is a 400 meter long "wooden footbridge" that directs the visitor over the beach wall and from here allows a view over a wide coastal landscape and the small inland lake. A section of the beach is closed to visitors here. This section is designated as a breeding area for the Red List Little Tern and the rare Ringed Plover. On the west side of the inland lake, one can often see white-tailed eagles and cranes from an observation post.