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Staphylinidae of Mellum Island (German Bight)

(sampled with pitfall & colour traps 1984-1986)

Summary and correction of the list of species by Rose & Möhlmann (1993) - Drosera `93 (1/2): 101-123.

Zur Besiedlung der jungen Düneninsel Mellum durch Kurzflügler (Coleoptera; Staphylinidae)

[Colonization of the young dune island Mellum by staphylinid beetles (Coleoptera: Staphylinidae)]

Abstract: Between 1984 and 1986, 9443 staphylinid specimens out of 133 species were caught in pitfall traps and colour dishes on Mellum island, 17 of which had not been recorded on the old East Frisian Islands and two of which had not been found in Lower Saxony before. At least 60 of these species (45,1 %) are indigenous and two are xenotopic (1,5 %). For further 71 species (53,4 %) indigenousness cannot be excluded. The most abundant species were Drusilla canaliculata, Sepedophilus marshami, and Tachinus signatus, of which phenologies are shown. 82 species (61 %) are eurytopic, 34 (26 %) are ubiquitous and further 17 species (13 %) are stenotopic. Eight species are typical coastal inhabitants, concerning Bledius subniger, Bl. tricornis, Brundinia marina, Diglotta mersa, Halobrecta puncticeps, Heterothops binotatus, Phytosus balticus and Stenus intermedius.

Four different areas were investigated of which the crouch grass zone proved to be richest in species (70), followed by the "Ringdeich" area (66), the salt marshes (52) and the more isolated Northern Dunes (39). The salt marshes were most equable as far as activity dominance structure was concerned.

Furthermore, size structures of the staphylinidocenoses on Mellum island were examined. The crouch grass zone was noticeable because of its great share of large species. 13,3 % of the Northwest German species were found on Mellum island.

Compared to the likewise carnivorous carabids and spiders the colonization success of the staphylinids on Mellum island is quite low, however, compared to the phytophagous beetles it is high. Mostly euryoecious species and among the stenoecious species inhabitants of marine influenced environments were successful in colonization.

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List of species

Table 2: List of staphylinid species (excl. Scaphidiinae & Pselaphinae) found at Mellum island from 1984 to 1986 [PT: pitfall traps, CT: colour traps - R: "Ringdeichgebiet" (anthropogenous area within a dike), Q: "Queckenzone" (crouch grass zone), S: " Salzwiesen" (salt marsh), D: "Norddünen" (dune area) - x: sparse in this area, 1: subrecedent, 2: recedent, 3: subdominant, 4: dominant, 5: eudominant {for dominances only catches from pitfall traps 1984 & 1985}]