Older Dryas - Description

Description

Northern Europe offered an alternation of steppe and tundra environments depending on the permafrost line and the latitude. In moister regions around lakes and streams were thickets of dwarf birch, willow, sea buckthorn, and juniper. In the river valleys and uplands to the south were open birch forests.

The first trees, birch and pine, had spread into north Europe 500 years previously. During the Older Dryas, the glacier advanced again and the trees retreated southward, to be replaced by a mixture of grassland and cool-weather alpine species. This type of biome has been called “Park Tundra”, “Arctic tundra”, “Arctic pioneer vegetation” or “birch woodlands.” It exists today in the transition between taiga and tundra in Siberia. Then it stretched from Siberia to Britain in a more or less unbroken expanse.

To the northwest was the Baltic ice lake, which was truncated by the edge of the glacier. Species had access to Denmark and southern Sweden. Most of Finland and the Baltic countries were under the ice or the lake for most of the period. Northern Scandinavia was glaciated. Between Britain and the mainland were rolling hills prolifically populated with animals. Thousands of specimens, hundreds of tons of bones, have been recovered from the bottom of the North Sea, termed “doggerland”, and continue to be recovered.

The brief lists of plants and animals stated below are a fraction of the total number of species found for the period. Most families were more diverse than they are today, and were yet more so in the last interglacial. A great extinction, especially of mammals, continued throughout the end of the Pleistocene, and may be continuing today.