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The spider fauna of two intensively grazed pastures was studied by means of pitfall trap ing and quadrat sampling. Special attention was paid to the distribution of the spiders in islets of higPher grass and shortgrazed patches during day and night. An overall relationship was found between the preference for one of the two studied microhabitats and the diurnal activity: s iders active durin the night show a preference for higher vegetation (e Pachygnatha clercki, Oedotiorax upicatus) an%day active spiders prefer short vegetation (e.g. Purli?dsa-species, Erigone dentipalpis). Oedothorax fuscus and 0. retusus are shown to retire in the islets at night. Some abiotic and biotic characteristics of high and short vegetation were studied. Based on observations of certain abiotic and biotic parameters, explanations for the differences in spider fauna of the two microhabitats are postulated.From the point of nature conservation it would therefore seem to be worthwhile to try to combine both high and low vegetation in one particular habitat. Extensive grazing has been proposed as a management practice to accomplish such combination of the two structural microhabitats (MORRIS 1969). U.S. Copyright Clearance Center Code Statement: 0044-2240/89/0705-0455 $ 02.50/0 693-710. of Carabidae in agroecosystems. Pedobiologia 23, 295-303. sampling methods, and population characteristics. J. Anim. Ecol. 31, 571-599. 15-34.

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