Amara strenua Zimmermann, 1832 (Coleoptera, Carabidae) is reported for the first time from Switzerland (from Lohningen in the Klettgau region, canton Schaffhausen). This is a rare European species that occurs mainly along the large rivers and their tributaries. It was found in Switzerland in a xerothermic strip of grass on the margin of a field along a field path. According to the literature this is a characteristic species of regularly inundated floodplain grassland. The species was found in Switzerland in a very different type of habitat.

1993 fuhrte der Bund okologische Direktzahlungen ein; seit 1999 ist die Erbringung des okologischen Leistungsnachweises (OLN) durch die Landwirtschaftsbetriebe die Voraussetzung zum Bezug von Direktzahlungen. Heute werden 97 % der landwirtschaftlichen Nutzflache nach den Regeln des OLN bewirtschaftet. Die wichtigste Massnahme des OLN, welche einen Einfluss auf die Biodiversitat hat, ist, dass die Betriebe 7 % ihrer landwirtschaftlichen Nutzflache (LN) als okologische Ausgleichsflachen (oAF) auszuweisen haben (bei Spezialkulturen 3,5 %). Weitere Anforderungen des OLN (ausgeglichene Nahrstoffbilanz, geregelte Fruchtfolge, Bodenschutz, gezielter Einsatz von Pflanzenschutzmitteln, tiergerechte Haltung der Nutztiere) konnen ebenfalls einen Einfluss haben, stehen jedoch weniger im Vordergrund.

Anbausysteme, die die Umwelt nur wenig belasten und die biologische Vielfalt fordern, werden zunehmend im Rahmen von EU-Agrarumweltprogrammen finanziell gefordert. Dass Synergieeffekte bei der Kombination von naturnahen Flachen und Biolandbau moglich sind, zeigt eine FiBL-Studie.

Ground-living spiders on arable land in north-westem Switzerland with a Central European comparison (Arachnida: Araneae). The ground-living spider fauna of north-westem Switzerland is analysed in a general view during the years 1993-1998 based on 67 data sets. Two species (Oedothorax apicatus, Pardosa agrestis) dominated c1early. 14 species had representing values of 80 to 100 %, 9 species from 50 to 80% and 18 species from 20 to 50 %. Eperigone trilobata and Pardosa proxima are geographically typical. A total of 131 species and 52'878 adult spiders were included in this analysis. An additional analysis of 47 investigations around Central Europe yielded four species (Oedothorax apicatus, Erigone atra, Erigone dentipalpis, Meioneta rurestris) occurring in all regions abundantly and regularly in the arable fields. Six additional species occur in all regions in the fields - in some investigations or regions less abundant. We found a biogeographic gradient in some species (increasing abundance from Western to Central and Eastem Europe: Pardosa agrestis). Other species are only abundant in some regions - this is caused by present expansion (Eperigone trilobata) or the border of distribution (Dip/ocephalus graecus). ln general the ground-living spider fauna on arable land in Central Europe is characterised by a uniform pattem.

Carabid populations (species diversity and abundance) in different crops were investigated during the period from April to July 1993 to 1995. The study was carried out on two farms in North-Western Switzerland. Nine fields with winter cereals (4x wheat, 2x spelt, 2x barley, lx rye), three rape fields, five spring cultures (3x maize, lx soybeans, lx potatoes) and an arable meadow were studied. In winter cereals, more carabid species were found than in spring cultures. In barley, we recorded fewer carabid species and individuals, larger numbers of hygrophilaus carabids and a more even population structure than in the other cereals. In rape, we recorded the highest numbers of carabid species and individuals, and very large numbers of Amara similata and A ovat(t. Rape turned out to be an attractive foocl plant for A. similata and A. avata. Pterosticlms melanarius was less abundant in rape than in cereals. In the springcultures, we found less species and individuals than in cereals or rape. but a lugher share of xerothermophilous carabid species. There were significant differences in the carabid populations on the two farms, which might be explained by the different farming methods. One farm is managed organically, while the other farm applies integrated production. Among others, organic farms are not allowed to use herbicides. Therefore, the weed flora on organic fields is generally richer than on other fields, and the microclimate on the soil smface can be favourable. From April to June, Poecilus CUJJreus was the most frequent carabid species on both farms. In July, P. cupreus was still the most abundant carabid on the organic farm, while Pterostichus melanarius became the most abundant carabid on the integrated farm. Due to the bigher weed diversity Amara plebeja, A. fami/iaris,Diachmmus germanus and Stenolophus teutonus occurred mostly more abundant on the organic fields.

We conducted investigations about the effects of different farming systems and seminatural habitats on beneficial organisms. On one hand, it was performed in a long-term comparison trial of different farming systems (DOC-trial) and on the other hand also on the farm Ievel. Beneficial artbropods and earthworm populations were mostly investigated in arable fields and also in the adjacent field margins and seminatural habitats. In most cases, carabid populations of organic fields were richer in species and abundance and also the abundances and biomasses of earthworms were greater than in the integrated farmed plots. The spider fauna did not differ so significantly in dependance of tbe farming intensity. Endangered and rare carabid and spider species were generally more abundant in the organic fields. Summerand winter data have sbown that seminatural habitats and field margins play a key role as refugia and overwintering sites for many beneficial artbropods. In conclusion tbe data showed that organic farming in combination with seminatural habitats and field margins are crucial factors for a sustainable conservation and enbancement of the indigenous beneficial fauna on the agriculturalland.

Im Rahmen zweier Projekte, fur die Fange im Raum Basel durchgefuhrt wur­den, konnten zwei Spinnenarten erstmals fur die Schweiz nachgewiesen werden. Alle Tiere wurden mit Hilfe von Trichter-Bodenfallen durch die Coautoren gefan­ gen. Die Determination erfolgte durch den Erstautor. Beide Belege werden im Naturhistorischen Museum Basel hinterlegt.

Der Einfluss von eingesaten Wildblumenstreifen (Buntbrachen) auf die Laufkafer- und Spinnenfauna der ehemaligen Flachmoorlandschaft und heute intensiv bewirtschafteten Kulturlandschaft "Grosses Moos" (Schweizer Mittelland: Berner Seeland) wurde untersucht. Drei mit einheimischen Wild- und Kulturpflanzen eingesate Wildblumenstreifen verschiedenen Alters sowie die angrenzenden Getreidekulturen in 15 m (Randbereich) und in 70 bis 100 m (Zentrumsbereich) Entfernung vom Wildblumenstreifen wurden mittels Trichterbodenfallen wahrend 10 Fangwochen von Mai bis Juli 1999 beprobt. Von den 123 in 44.161 Individuen nachgewiesenen Laufkafer- und Spinnenarten wurden insgesamt 110 in Wildblumenstreifen, 85 in den Randbereichen und 82 Arten in den Zentrumsbereichen der Getreideflachen gefunden. Die Aktivitatsdichte der Laufkafer und Spinnen in den Wildblumenstreifen waren hingegen am niedrigsten. Viele stenotope Grunlandarten kamen ausschlieslich oder vorwiegend in den Wildblumenstreifen vor. Die Artengemeinschaften der Laufkafer und Spinnen in den Getreiderandbereichen waren von Wildblumenstreifen positiv beeinflusst und wiesen eine entsprechend hohere Artenvielfalt auf, als die Zentrumsbereiche der Felder. Wildblumenstreifen stellen fur viele Laufkafer und Spinnen einen geeigneten Lebensraum dar und tragen dadurch zur Nutzlingsforderung und Erhohung der Artenvielfalt der untersuchten Standorte bei.