Colonisation by plants and animals and subsequent biotic development in west Greenland was studied by analyses of macrofossils in four Holocene lake sequences. One of the lake basins, located near the outer coast, was deglaciated shortly after the transition from the last glacial stage to the Holocene, and a basal date of 12,100-11,300 cal. years BP was obtained. Two of the lake basins located near the margin of the Greenland ice sheet were deglaciated several millennia later. The oldest sediments contain low-diversity floras and faunas. Some of the first immigrants were Chironomidae and Daphnia pulex, soon followed by other insects, crustaceans and other invertebrates. Water mosses, Ranunculus confervoides, Hippuris vulgaris and Potamogeton filiformis were among the first plants that colonised the lakes. The earliest Holocene terrestrial flora in west Greenland was probably entirely herbaceous, with Salix herbacea and Empetrum nigrum being some of the first woody plants to arrive. A number of invertebrates are new to the fossil fauna of Greenland, and the ostracod Ilyocypris bradyi that was found in one sequence, from 7000 to 6500 cal. years BP, has not been recorded from Greenland before.
- Programområde 5: Natur og klima