Devensian Lateglacial palaeoecological changes in Shetland

Diatoms and plant macrofossils in Devensian Lateglacial lacustrine sediments in Shetland suggest that the earliest response to interstadial warming was from benthic aquatic communities that could develop under lake ice. Further warming permitted longer ice‐free summers and plankton growth. The terrestrial vegetation communities responded more slowly. Pollen of land plants was then partly derived from long distance input. Macrofossils support a reconstruction of terrestrial vegetation of sparse Salix herbacea and mosses in the early interstadial, increasing to grass tundra with tall herbs and Empetrum locally present, and with patches of disturbed ground. The occurrence of Betula and Juniperus remains questionable because of a lack of macrofossils, despite the presence of their pollen. Rumex pollen peaks suggest significant local presence at the stadial/interstadial transitions. Overall, the palaeoenvironmental reconstruction at this isolated oceanic site depends on several proxy indicators, of which pollen is less reliable than diatoms and plant macrofossils.