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Summary1. Habitat fragmentation is a major threat to biodiversity and can lead to the loss of both species and ecosystem services, but fragmentation effects vary greatly between studies and studied organisms. Understanding the distinct effects of habitat amount and isolation at the patch and landscape scale may account for some of this variation. 2. We studied biodiversity in 30 traditional orchards that were selected for independent variation in habitat amount and habitat isolation at the patch and landscape scale. We analysed species richness and abundance of snails, beetles, true bugs, spiders and breeding birds that avoid open farmland but occur in woody vegetation types. Additionally, the abundances of nine single species were analysed using specific habitat definitions. 3. Surprisingly, the effects of habitat isolation were more important than the effects of habitat amount. Effects at the patch scale were more frequent than landscape-scale effects. 4. Spider species richness decreased with increasing patch-scale habitat amount. Abundance of the weevil Phyllobius oblongus increased with landscape-scale habitat amount. Negative effects of patch isolation were greater for predatory birds and spiders, while the predominately herbivorous beetles, true bugs and snails were less affected. Species richness of birds, spiders and beetles, and abundance of birds, Cyanistes caeruleus, Parus major and Fringilla coelebs, decreased with increasing patchscale habitat isolation. In contrast, species richness of spiders and beetles increased with increasing landscape-scale habitat isolation. 5. Synthesis and applications. The effects of habitat fragmentation differed between taxonomic groups, with stronger and more consistent responses in birds than invertebrates. Our understanding of fragmentation effects may be biased due to the dominance of bird studies in the literature, and further invertebrate studies are encouraged. Landscape management to improve biodiversity or ecosystem services requires a group-specific approach and coordinated priority setting. High habitat connectivity benefited wood-preferring birds, spiders and beetles, lending support to national initiatives for increased habitat connectedness. The negative effects of patch isolation were greater for natural pest regulators, birds and spiders than for herbivorous beetles and bugs.

Aim  Geographic body size patterns of mammals and birds can be partly understood under the framework of Bergmann’s rule. Climatic influences on body size of invertebrates, however, appear highly variable and lack a comparable, generally applicable theoretical framework. We derived predictions for body size–climate relationships for spiders from the literature and tested them using three datasets of variable spatial extent and grain. Location  Europe. Methods  To distinguish climate from space, we compared clines in body size within three datasets with different degrees of co‐variation between latitude and climate. These datasets were: (1) regional spider faunas from 40 European countries and large islands; (2) local spider assemblages from standardized samples in 32 habitats across Europe; and (3) local spider assemblages from Central European habitats. In the latter dataset climatic conditions were determined more by habitat type than by geographic position, and therefore this dataset provided a non‐spatial gradient of various microclimates. Spider body size was studied in relation to latitude, temperature and water availability. Results  In all three datasets the mean body size of spider assemblages increased from cool/moist to warm/dry environments. This increase could be accounted for by turnover from small‐bodied to large‐bodied spider families. Body size–climate relationships within families were inconsistent. Main conclusions  Starvation resistance and accelerated maturation can be ruled out as explanations for the body size clines recorded, because they predict the inverse of the observed relationship between spider body size and temperature. The relationship between body size and climate was partly independent of geographic position. Thus, the restriction of large‐bodied spiders to their glacial refugia owing to dispersal limitations can be excluded. Our results are consistent with mechanisms invoking metabolic rate, desiccation resistance and community interactions to predict a decrease in body size from warm and dry to cool and moist conditions.

Habitat loss and fragmentation are major threats to biodiversity and ecosystem functioning. Effects of these usually intercorrelated processes on biodiversity have rarely been separated at a landscape scale. We studied the independent effects of amount of woody habitat in the landscape and three levels of isolation from the next woody habitat (patch isolation) on trap nesting bees, wasps, and their enemies at 30 farmland sites in the Swiss plateau. Species richness of wasps was negatively affected by patch isolation and positively affected by the amount of woody habitat in the landscape. In contrast, species richness of bees was neither influenced by patch isolation nor by landscape composition. Isolation from woody habitats reduced species richness and abundance of natural enemies more strongly than of their hosts, so that parasitism rate was lowered by half in isolated sites compared to forest edges. Thus, population regulation of the hosts may be weakened by habitat fragmentation. We conclude that habitat amount at the landscape scale and local patch connectivity are simultaneously important for biodiversity conservation.

Habitat loss and fragmentation lead to changes in species richness and composition which may affect ecosystem services. Yet, few studies distinguish between the effects of habitat loss and isolation, or how multiple ecosystem services may be affected simultaneously. We investigated the effects of variation in cover of woody and open semi-natural habitats and isolation from forest on the relative functioning of pollination, seed predation and insect scavenging in agricultural landscapes. We established 30 sites in grassland locations in the Swiss plateau around Berne. The sites varied independently in their isolation from forest edges, in the percentage of woody habitats and in the percentage of open seminatural habitats in the surrounding landscape (500 m radius). We experimentally exposed primroses, sunflower seeds and cricket corpses during spring 2008. None of the three studied services was affected by variation in woody or open semi-natural habitat cover. However, the proportion of flowers setting seed was significantly reduced by isolation from forest. Further, seed predation and insect scavenging were significantly lower at isolated sites than at sites connected to woody habitat. This pattern was particularly pronounced for seeds and insect corpses that were enclosed by wire netting and thus inaccessible to vertebrates. Thus, all three studied services responded quite similarly to the landscape context. The observed small-scale determination of seed set, seed predation and insect scavenging contrasts with larger-scale determination of pollination and insect pest control found in other studies.