Some of the species represented here, such as the Purple Golden-drop, (Onosma arenaria) grow only here and in small numbers.
The sand dunes developed after the last ice age (Würm glaciation[broken anchor]) and the first resettlement of grassland plants occurred approximately 12,000 years ago.
[citation needed] The dry sandy soils are poor of nutrients but relict flora from the glaciation grasslands grow favorably.
[1] In the late Pleistocene, just before the end of the last ice age and during the short summers, sand-drifts were blown from the Rhine Valley into the area of the present dunes, forming this unique geology.
The soil consists almost solely of high lime component with fine white sand, which barely retains water and nutritive but is easily warmed by sunlight.