Staphylinidae of Lütje Hörn Island (German Bight)

(sampled with pitfall traps 1989 and 1990)

Summary and downloadable pdf-file of Rose (1998) - Abh. Naturw. Verein Bremen 44 (1): 135-145.

Die Besiedlung von Düneninseln früher Sukzessionsstadien im Nationalpark Niedersächsisches Wattenmeer durch Kurzflügler (Coleoptera: Staphylinidae) am Beispiel von Lütje Hörn

[Colonization by rove beetles (Coleoptera: Staphylinidae) on Lütje Hörn Island as example of a dune island in early stage of succession in Lower Saxony Waddensea National Park]

Abstract: In 1989 and 1990, 1285 rove beetles out of 70 species were caught in pitfall traps on Lütje Hörn island, one of which (Stenus bohemicus Mach.) never being recorded on the old East Frisian Islands before. 24 species (34%) were considered to be indigenous even though the rescue effect may lead to misinterpretation. Compared to Northwestern Germany, the proportion of coastal species, and those at least halotolerant as well as inhabitants of sandy shores, is quite high on Lütje Hörn. Also the proportion of older dune and shore deposit inhabitants is high, compared to Northwestern Germany. Finally, Lütje Hörn is rich in saprophilous species.

Flight activity, often coming along with saprophily of several rove beetle species, seems to contribute considerably in early colonization of dune islands by those species. Strong evidence for this is a significant correlation (r=0.873; a=0.01) between flight activity in the coastal area (measured by occurence in colour traps on other islands) and the occurence of species rich subfamilies (20 and more species) of rove beetles on the young dune island Lütje Hörn.

Another good indication for a connection between flight activity and early island colonization is shown by a comparison of the results of the two years of investigation. As a lucky coincidence (for science), in winter 1989/90 (before the second investigation took place) several strong stormtides inundated the entire island. Hence, there had to be nearly a complete recolonization by beetles in spring 1990. As a most probable consequence of this, on Lütje Hörn a greater proportion of flight-active species (especially among the more abundant species) had been recorded in 1990 compared to 1989. Other possible ways of colonization are the water surface (hydrochorous) and phoresy, but surely flight is a major factor for colonization.

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