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© 2016, Oxford University Press. All rights reserved. Field edge habitat in homogeneous agricultural landscapes can serve multiple purposes including enhanced biodiversity, water quality protection, and habitat for beneficial insects, such as native bees and natural enemies. Despite this ecosystem service value, adoption of field border plantings, such as hedgerows, on large-scale mono-cropped farms is minimal. With profits primarily driving agricultural production, a major challenge affecting hedgerow plantings is linked to establishment costs and the lack of clear economic benefits on the restoration investment. Our study documented that hedgerows are economically viable to growers by enhancing beneficial insects and natural pest control and pollination on farms. With pest control alone, our model shows that it would take 16 yr to break even from insecticide savings on the US$4,000 cost of a typical 300-m hedgerow field edge planting. By adding in pollination benefits by native bees, where honey bees (Apis mellifera L.) may be limiting, the return time is reduced to 7 yr. USDA cost share programs allow for a quicker return on a hedgerow investment. Our study shows that over time, small-scale restoration can be profitable, helping to overcome the barrier of cost associated with field edge habitat restoration on farms.

Fil: Garibaldi, Lucas Alejandro. Universidad Nacional de Río Negro. Sede Andina; Argentina. Fil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Carvalheiro, Luísa G. University of Leeds; Reino Unido. Naturalis Biodiversity Center; Países Bajos Fil: Leonhardt, Sara D. University of Würzburg; Alemania Fil: Aizen, Marcelo A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Aizen, Marcelo A. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Aizen, Marcelo A. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche; Argentina Fil: Blaauw, Brett R. Michigan State University; Estados Unidos Fil: Rufus, Isaacs. Michigan State University; Estados Unidos Fil: Kuhlmann, Michael. Natural History Museum; Reino Unido Fil: Kleijn, David. Wageningen University; Países Bajos Fil: Klein, Alexandra M. University of Freiburg; Alemania Fil: Kremen, Claire. University of California at Berkeley; Estados Unidos Fil: Morandin, Lora. University of California at Berkeley; Estados Unidos Fil: Scheper, Jeroen. Animal Ecology Team, Wageningen; Países Bajos Fil: Winfree, Rachael. Rutgers University; Estados Unidos Recent evidence highlights the value of wild-insect species richness and abundance for crop pollination world-wide. Yet, deliberate physical importation of single species (eg European honey bees) into crop fields for polli-nation remains the mainstream management approach, and implementation of practices to enhance cropyield (production per area) through wild insects is only just beginning. With few exceptions, studies measur-ing the impacts of pollinator-supporting practices on wild-insect richness and pollination service success – par-ticularly in relation to long-term crop yield and economic profit – are rare. Here, we provide a general frame-work and examples of approaches for enhancing pollinator richness and abundance, quantity and quality ofpollen on stigmas, crop yield, and farmers’ profit, including some benefits detected only through long-termmonitoring. We argue for integrating the promotion of wild-insect species richness with single-species man-agement to benefit farmers and society.

Within-farm habitat enhancements such as hedgerows could aid pest control in adjacent crops; however, there is little information on whether small-scale restoration impacts pests and natural enemies, and crop damage, and how far effects may extend into fields. We compared restored, California native perennial hedgerows to unenhanced field edges consisting of commonly occurring semi-managed, non-native weeds. Pest and natural enemy communities were assessed in both edge types and into adjacent processing tomato fields. Using sentinel pest eggs, pest control was quantified, and pest pressure and crop damage was compared between field types. Economically-important pests were fewer and parasitoid wasps were more abundant in hedgerows than weedy crop edges. There was no difference in predatory arthropod abundance between edge types, but there was greater predator richness in hedgerow than weedy edges. Predatory lady beetles were more abundant and aphids were lower in fields with hedgerows, up to 200. m into fields, the maximum extent of observations. Fewer of the fields adjacent to hedgerows reached threshold pest levels requiring insecticide application. Benefits of hedgerows to pest control from parasitism extended to 100. m but not 200. m into fields. Farm-scale hedgerow restoration can provide pest control benefits up to 100 or 200. m into fields and multiple hedgerows around fields could enhance pest control throughout entire fields, reducing the need for chemical pest control. © 2014 Published by Elsevier B.V.

Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 crop systems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Bee responses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture. Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 cropsystems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Beeresponses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on boththe maintenance of high-quality habitats around farms and on local management practices that may offsetimpacts of intensive monoculture agriculture.

Habitat restoration to promote wild pollinator populations is becoming increasingly common in agricultural lands. Yet, little is known about how wild bees, globally the most important wild pollinators, use resources in restored habitats. We compared bee use of native and exotic plants in two types of restored native plant hedgerows: mature hedgerows (>10 years from establishment) designed for natural enemy enhancement and new hedgerows (≤2 years from establishment) designed to enhance bee populations. Bees were collected from flowers using timed aerial netting and flowering plant cover was estimated by species using cover classes. At mature hedgerow sites, wild bee abundance, richness, and diversity were greater on native plants than exotic plants. At new sites, where native plants were small and had limited floral display, abundance of bees was greater on native plants than exotic plants; but, controlling for floral cover, there was no difference in bee diversity and richness between the two plant types. At both mature and new hedgerows, wild bees preferred to forage from native plants than exotic plants. Honey bees, which were from managed colonies, also preferred native plants at mature hedgerow sites but exhibited no preference at new sites. Our study shows that wild bees, and managed bees in some cases, prefer to forage on native plants in hedgerows over co-occurring weedy, exotic plants. Semi-quantitative ranking identified which native plants were most preferred. Hedgerow restoration with native plants may help enhance wild bee abundance and diversity, and maintain honey bee health, in agricultural areas. © 2012 Society for Ecological Restoration.