SignificanceDecades of research have fostered the now-prevalent assumption that noncrop habitat facilitates better pest suppression by providing shelter and food resources to the predators and parasitoids of crop pests. Based on our analysis of the largest pest-control database of its kind, noncrop habitat surrounding farm fields does affect multiple dimensions of pest control, but the actual responses of pests and enemies are highly variable across geographies and cropping systems. Because noncrop habitat often does not enhance biological control, more information about local farming contexts is needed before habitat conservation can be recommended as a viable pest-suppression strategy. Consequently, when pest control does not benefit from noncrop vegetation, farms will need to be carefully comanaged for competing conservation and production objectives.

† These authors have contributed equally to this work.The concept of ecosystem services was originally developed to illustrate the benefits that natural ecosystems generate for society and to raise awareness for biodiversity and ecosystem conservation. In this article we identify major challenges and opportunities for ecologists involved in empirical or modeling ecosystem service research. The first challenge arises from the fact that the ecosystem service concept has not been generated in the context of managed systems. Ecologists need to identify the effect of anthropogenic interventions in order to propose practices to benefit service-providing organisms and associated services. The second challenge arises from the need to evaluate relationships between indicators of ecosystem services that are collected in ecological studies while accounting for uncertainties of ecological processes that underlie these services. We suggest basing the assessment of ecosystem services on the utilization of sets of indicators that cover aspects of service-providing units, ecosystem management and landscape modification. The third challenge arises from the limited understanding of the nature of relationships between services and a lack of a general statistical framework to address these links. To manage ecosystem service provisioning, ecologists need to establish whether services respond to a shared driver or if services are directly linked to each other. Finally, studies relating biodiversity to ecosystem services often focus on services at small spatial or short temporal scales, but research on the protection of services is often directed toward services providing benefits at large spatial scales. Ecological research needs to address a range of spatial and temporal scales to provide a multifaceted understanding of how nature promotes human well-being. Addressing these challenges in the future offers a unique opportunity for ecologists to act as promoters for the understanding about how to conserve benefits gained from nature.

Agricultural management and vegetation complexity affect arthropod diversity and may alter trophic interactions between predators and their prey. Web-building spiders are abundant generalist predators and important natural enemies of pests. We analyzed how management intensity (tillage, cutting of the vegetation, grazing by cattle, and synthetic and organic inputs) and vegetation complexity (plant species richness, vegetation height, coverage, and density) affect rarefied richness and composition of web-building spiders and their prey with respect to prey availability and aphid predation in 12 habitats, ranging from an uncut fallow to a conventionally managed maize field. Spiders and prey from webs were collected manually and the potential prey were quantified using sticky traps. The species richness of web-building spiders and the order richness of prey increased with plant diversity and vegetation coverage. Prey order richness was lower at tilled compared to no-till sites. Hemipterans (primarily aphids) were overrepresented, while dipterans, hymenopterans, and thysanopterans were underrepresented in webs compared to sticky traps. The per spider capture efficiency for aphids was higher at tilled than at no-till sites and decreased with vegetation complexity. After accounting for local densities, 1.8 times more aphids were captured at uncut compared to cut sites. Our results emphasize the functional role of web-building spiders in aphid predation, but suggest negative effects of cutting or harvesting. We conclude that reduced management intensity and increased vegetation complexity help to conserve local invertebrate diversity, and that web-building spiders at sites under low management intensity (e.g., semi-natural habitats) contribute to aphid suppression at the landscape scale.

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Productive and non‐productive agri‐environmental schemes (AES) were developed to support farmland biodiversity. This study compares arthropod predators between productive (organic farming) and non‐productive (sown flowering fields) AES along a landscape complexity gradient. We compared species richness, community composition and community weighted mean body sizes of 12 306 carabids and 4868 spiders in organically managed cereal fields and flowering fields along a landscape complexity gradient. These data were used to evaluate the conservation success of different AES types for a number of exclusive species, financial incentives and benefits for farmers. Carabids only responded to the AES type and their communities had higher species richness in flowering fields. Spider species richness increased with landscape complexity. Community composition differed between AES types for all predator groups, with the composition of ground‐dwelling spiders being additionally affected by landscape complexity. The mean body size of web‐building spiders decreased with landscape complexity and the mean body size of female spiders was larger in flowering fields. Both AES types can contribute to the conservation of predator communities. Species richness increased with non‐productive AES. Agrobiont species occurred more frequently in productive AES. The overall number of exclusive predator species was lower in flowering fields. We emphasise that there is an additive effect of establishing productive and non‐productive AES within the landscape, and a diverse mosaic of different AES types holds the greatest potential to provide a large regional species pool of arthropod predators, while simultaneously guaranteeing financial benefits for farmers from production and subsidies.