(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.