LATE LAND CONNECTIONS IN THE NORTH ATLANTIC AREA 



75 



Diaptomus species are able to produce thick-walled winter eggs, very resistant 

 to desiccation (Wesenberg-Lund, 1937, p. 523, etc.). Considering the geo- 

 graphical position of Iceland, much closer to Greenland {ca. 300 km) than to 

 the European mainland (Norway ca. 950 km) and the British Isles {ca. 800 km), 

 the extremely poor representation of a Nearctic element is indeed surprising. 

 Furthermore, it seems to consist exclusively of species with above average 

 ability of dispersal. There is little doubt that the Nearctic animals and plants 

 of Iceland were able to invade the island by active flight or by passive, "non- 

 human" transport during present-day conditions. 



Table 2. Representative Groups of the Terrestrial Greenland Fauna 

 Indigenous species and subspecies. Endemic subspecies of birds are distributed among the 

 three geographical groups according to their taxonomic relation to other subspecies (from 



Lindroth, 1957). 



The fauna of Greenland, if distributed among geographical groups (Table 

 2), is a veritable "mixture". Roughly counted, it consists of one-half Circum- 

 polar taxa, and about one-quarter each of Nearctic and Palearctic forms, 

 respectively. 



However, it is easily observed that different animal groups behave differently 

 in this respect. The highest percentages of Palearctic forms are found among 

 Coleoptera and Collembola; among Nearctic forms the highest frequency 

 occurs in Araneae, Lepidoptera, and Aves. This is, of course, a biological and 

 not a taxonomical feature. It is an expression for differences in dispersal 

 ability : The Nearctic element of the Greenlandic fauna consists of a high 

 proportion of easily dispersed animals, able to traverse at least moderate 

 distances over the sea by active flight or by passive, aerial transport. The 

 Palearctic element includes many soil-bound species not easily dispersed by 

 these or other methods. 



A closer examination of the entire Coleopterous fauna of the North Atlantic 

 islands provides a clearer picture (Fig. 1). The purely Palearctic character of 

 the fauna of the Faeroes and Iceland is strongly manifest and, what is more 

 itnportant, the species concerned are to a great extent flightless and thus not 



