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There is increasing evidence that farmers in many areas are achieving below maximum yields due to insufficient pollination. Practical and effective approaches are needed to maintain wild pollinator populations within agroecosystems so they can deliver critical pollination services that underpin crop production. We established nesting and wildflower habitat interventions in 24 UK apple orchards and measured effects on flower-visiting insects and the pollination they provide, exploring how this was affected by landscape context. We quantified the extent of pollination deficits and assessed whether the management of wild pollinators can reduce deficits and deliver improved outcomes for growers over 3 years. Wildflower interventions increased solitary bee numbers visiting apple flowers by over 20%, but there was no effect of nesting interventions. Other pollinator groups were influenced by both local and landscape-scale factors, with bumblebees and hoverflies responding to the relative proportion of semi-natural habitat at larger spatial scales (1000 m), while honeybees and other flies responded at 500 m or less. By improving fruit number and quality, pollinators contributed more than £16 k per hectare. However, deficits (where maximum potential was not being reached due to a lack of pollination) were recorded and the extent of these varied across orchards, and from year to year, with a 22% deficit in output in the worst (equivalent to ~£14 k/ha) compared to less than 3% (equivalent to ~£2 k/ha) in the best year. Although no direct effect of our habitat interventions on deficits in gross output was observed, initial fruit set and seed set deficits were reduced by abundant bumblebees, and orchards with a greater abundance of solitary bees saw lower deficits in fruit size. The abundance of pollinators in apple orchards is influenced by different local and landscape factors that interact and vary between years. Consequently, pollination, and the extent of economic output d

Agri-environment schemes are programmes where landholders enter into voluntary agreements (typically with governments) to manage agricultural land for environmental protection and nature conservation objectives. Previous work at local scale has shown that these features can provide additional floral and nesting resources to support wild pollinators, which may indirectly increase floral visitation to nearby crops. However, the effect of entire schemes on this important ecosystem service has never previously been studied at national scale. Focusing on four wild pollinator guilds (ground-nesting bumblebees, tree-nesting bumblebees, ground-nesting solitary bees, and cavity-nesting solitary bees), we used a state-of-the-art, process-based spatial model to examine the relationship between participation in agri-environment schemes across England during 2016 and the predicted abundances of these guilds and their visitation rates to four pollinator dependent crops (oilseed rape, field beans, orchard fruit and strawberries). Our modelling predicts that significant increases in national populations of ground-nesting bumblebees and ground-nesting solitary bees have occurred in response to the schemes. Lack of significant population increases for other guilds likely reflects specialist nesting resource requirements not well-catered for in schemes. We do not predict statistically significant increases in visitation to pollinator-dependent crops at national level as a result of scheme interventions but do predict some localised areas of significant increase in bumblebee visitation to crops flowering in late spring. Lack of any significant change in visitation to crops which flower outside this season is likely due to a combination of low provision of nesting resource relative to floral resource by scheme interventions and low overall participation in more intensively farmed landscapes. We recommend future schemes place greater importance on nesting resource provision alongside flo

Food system resilience has multiple dimensions. We draw on food system and resilience concepts and review resilience framings of different communities. We present four questions to frame food system resilience (Resilience of what? Resilience to what? Resilience from whose perspective? Resilience for how long?) and three approaches to enhancing resilience (robustness, recovery, and reorientation—the three “Rs”). We focus on enhancing resilience of food system outcomes and argue this will require food system actors adapting their activities, noting that activities do not change spontaneously but in response to a change in drivers: an opportunity or a threat. However, operationalizing resilience enhancement involves normative choices and will result in decisions having to be negotiated about trade-offs among food system outcomes for different stakeholders. New approaches to including different food system actors’ perceptions and goals are needed to build food systems that are better positioned to address challenges of the future. Expected final online publication date for the Annual Review of Environment and Resources, Volume 47 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Bees provide a vital ecosystem service to agriculture by contributing to the pollination of many leading global crops. Human wellbeing depends not only on the quantity of agricultural yields, but also on the stability and resilience of crop production. Yet a broad understanding of how the diversity and composition of pollinator communities may influence crop pollination service has previously been hindered by a scarcity of standardized data. We used outputs from Bayesian occupancy detection models to examine patterns in the inter-annual occupancy dynamics of the bee pollinator communities of four contrasting crops (apples, field bean, oilseed and strawberries) in Great Britain between 1985 and 2015. We compared how the composition and species richness of different crop pollinator communities may affect the stability of crop pollinator occurrence. Across the four crops, we found that the inter-annual occupancy dynamics of the associated pollinator communities tended to be more similar in smaller communities with closely related pollinator species. Our results indicate that crop pollinator communities composed of a small number of closely related bee species show greater variance in mean occupancy compared to crops with more diverse pollinator communities. Lower variance in the occurrence of crop pollinating bee species may lead to more stable crop pollination services. Finally, whilst our results initially indicated some redundancy within most crop pollinator communities, with no, or little, increase in the variance of overall mean occupancy when species were initially removed, this was followed by a rapid acceleration in the variance of crop pollinator occurrence as each crop's bee pollinator community was increasingly depreciated. High inter-annual variations in pollination services have negative implications for crop production and food security. High bee diversity could ensure more stable and resilient crop pollination services, yet current agri-environment schem

1. Wild bees provide a critical ecosystem service by pollinating globally important crops. Documented bee declines, notably in agricultural landscapes, therefore threaten future food security. Yet, evaluations of methods to inventory bees are rarely carried out in different crops or focus specifically upon crop pollinating species. 2. We utilise standardised field datasets to elucidate differences in the capacity of transect walks, observation plots and pan traps to sample wild bee pollinator communities in four contrasting crops. Our results indicate that individual survey methods detect different components of crop pollinator communities, with guild and body size potentially important causal factors behind these differences. 3. Transects detected half or less of the total potential pollinator community in three of our four study crops. Whilst transects were the most efficient method for sampling bumblebees, they often missed smaller solitary species, which were most efficiently sampled by yellow pan traps. 4. Crop type is likely an important determinant of the most suitable survey methods to sample bee pollinator communities. Whilst transects alone are sufficient in crops pollinated predominantly by bumblebees, pan traps, and potentially observation plots, may be an important addition in some crops where smaller solitary bee species are potentially important pollinators. 5. Our results indicate that the most efficient methods to sample bee species in agricultural landscapes are dependent upon crop type and pollinator community composition. We use our findings to make a set of recommendations on the inventorying and monitoring of bee pollinator crop communities that can inform regional and national monitoring programmes.

Pollinator declines have prompted efforts to assess how land-use change affects insect pollinators and pollination services in agricultural landscapes. Yet many tools to measure insect pollination services require substantial landscape-scale data and technical expertise. In expert workshops, 3 straightforward methods (desk-based method, field survey, and empirical manipulation with exclusion experiments) for rapid insect pollination assessment at site scale were developed to provide an adaptable framework that is accessible to nonspecialist with limited resources. These methods were designed for TESSA (Toolkit for Ecosystem Service Site-Based Assessment) and allow comparative assessment of pollination services at a site of conservation interest and in its most plausible alternative state (e.g., converted to agricultural land). We applied the methods at a nature reserve in the United Kingdom to estimate the value of insect pollination services provided by the reserve. The economic value of pollination services provided by the reserve ranged from US$6163 to US$11,546/year. The conversion of the reserve to arable land would provide no insect pollination services and a net annual benefit from insect-pollinated crop production of approximately $1542/year (US$24∙ha–1∙year–1). The methods had wide applicability and were readily adapted to different insect-pollinated crops: rape (Brassica napus) and beans (Vicia faba) crops. All methods were rapidly employed under a low budget. The relatively less robust methods that required fewer resources yielded higher estimates of annual insect pollination benefit.

1. Wild bees provide a critical ecosystem service by pollinating globally important crops. Documented bee declines, notably in agricultural landscapes, therefore threaten future food security. Yet, evaluations of methods to inventory bees are rarely carried out in different crops or focus specifically upon crop pollinating species. 2. We utilise standardised field datasets to elucidate differences in the capacity of transect walks, observation plots and pan traps to sample wild bee pollinator communities in four contrasting crops. Our results indicate that individual survey methods detect different components of crop pollinator communities, with guild and body size potentially important causal factors behind these differences. 3. Transects detected half or less of the total potential pollinator community in three of our four study crops. Whilst transects were the most efficient method for sampling bumblebees, they often missed smaller solitary species, which were most efficiently sampled by yellow pan traps. 4. Crop type is likely an important determinant of the most suitable survey methods to sample bee pollinator communities. Whilst transects alone are sufficient in crops pollinated predominantly by bumblebees, pan traps, and potentially observation plots, may be an important addition in some crops where smaller solitary bee species are potentially important pollinators. 5. Our results indicate that the most efficient methods to sample bee species in agricultural landscapes are dependent upon crop type and pollinator community composition. We use our findings to make a set of recommendations on the inventorying and monitoring of bee pollinator crop communities that can inform regional and national monitoring programmes.

Pollinators face multiple pressures and there is evidence of populations in decline. As demand for insect-pollinated crops increases, crop production is threatened by shortfalls in pollination services. Understanding the extent of current yield deficits due to pollination and identifying opportunities to protect or improve crop yield and quality through pollination management is therefore of international importance. To explore the extent of “pollination deficits,” where maximum yield is not being achieved due to insufficient pollination, we used an extensive dataset on a globally important crop, apples. We quantified how these deficits vary between orchards and countries and we compared “pollinator dependence” across different apple varieties. We found evidence of pollination deficits and, in some cases, risks of overpollination were even apparent for which fruit quality could be reduced by too much pollination. In almost all regions studied we found some orchards performing significantly better than others in terms of avoiding a pollination deficit and crop yield shortfalls due to suboptimal pollination. This represents an opportunity to improve production through better pollinator and crop management. Our findings also demonstrated that pollinator dependence varies considerably between apple varieties in terms of fruit number and fruit quality. We propose that assessments of pollination service and deficits in crops can be used to quantify supply and demand for pollinators and help to target local management to address deficits although crop variety has a strong influence on the role of pollinators.

The importance of wild bees for crop pollination is well established, but less is known about which species contribute to service delivery to inform agricultural management, monitoring and conservation. Using sites in Great Britain as a case study, we use a novel qualitative approach combining ecological information and field survey data to establish a national list of crop pollinating bees for four economically important crops (apple, field bean, oilseed rape and strawberry). A traits data base was used to establish potential pollinators, and combined with field data to identify both dominant crop flower visiting bee species and other species that could be important crop pollinators, but which are not presently sampled in large numbers on crops flowers. Whilst we found evidence that a small number of common, generalist species make a disproportionate contribution to flower visits, many more species were identified as potential pollinators, including rare and specialist species. Furthermore, we found evidence of substantial variation in the bee communities of different crops. Establishing a national list of crop pollinators is important for practitioners and policy makers, allowing targeted management approaches for improved ecosystem services, conservation and species monitoring. Data can be used to make recommendations about how pollinator diversity could be promoted in agricultural landscapes. Our results suggest agri-environment schemes need to support a higher diversity of species than at present, notably of solitary bees. Management would also benefit from targeting specific species to enhance crop pollination services to particular crops. Whilst our study is focused upon Great Britain, our methodology can easily be applied to other countries, crops and groups of pollinating insects.

1. Resilient pollination services depend on sufficient abundance of pollinating insects over time. Currently, however, most knowledge about the status and trends of pollinators is based on changes in pollinator species richness and distribution only. 2. Systematic, long‐term monitoring of pollinators is urgently needed to provide baseline information on their status, to identify the drivers of declines and to inform suitable response measures. 3. Power analysis was used to determine the number of sites required to detect a 30% change in pollinator populations over 10 years. We then evaluated the full economic costs of implementing four national monitoring schemes in the UK: (a) professional pollinator monitoring, (b) professional pollination service monitoring, (c) volunteer collected pan traps and (d) volunteer focal floral observations. These costs were compared to (a) the costs of implementing separate, expert‐designed research and monitoring networks and (b) the economic benefits of pollination services threatened by pollinator loss. 4. Estimated scheme costs ranged from £6,159/year for a 75‐site volunteer focal flower observation scheme to £2.7 M/year for an 800‐site professional pollination service monitoring network. The estimated research costs saved using the site network as research infrastructure range from £1.46–4.17 M/year. The economic value of UK crop yield lost following a 30% decline in pollinators was estimated at ~£188 M/year. 5. Synthesis and applications: We evaluated the full costs of running pollinator monitoring schemes against the economic benefits to research and society they provide. The annual costs of monitoring are <0.02% of the economic value of pollination services that would be lost after a 30% decline in pollination services. Furthermore, by providing high‐quality scientific data, monitoring schemes would save at least £1.5 on data collection per £1 spent. Our findings demonstrate that long‐term systematic monitoring can be a cost‐e

1. Pollination is a key ecosystem service for global agriculture but evidence of pollinator population declines is growing. Reliable spatial modelling of pollinator abundance is essential if we are to identify areas at risk of pollination service deficit and effectively target resources to support pollinator populations. Many models exist which predict pollinator abundance but few have been calibrated against observational data from multiple habitats to ensure their predictions are accurate. 2. We selected the most advanced process‐based pollinator abundance model available and calibrated it for bumblebees and solitary bees using survey data collected at 239 sites across Great Britain. We compared three versions of the model: one parameterised using estimates based on expert opinion, one where the parameters are calibrated using a purely data‐driven approach and one where we allow the expert opinion estimates to inform the calibration process. 3. All three model versions showed significant agreement with the survey data, demonstrating this model's potential to reliably map pollinator abundance. However, there were significant differences between the nesting/floral attractiveness scores obtained by the two calibration methods and from the original expert opinion scores. 4. Our results highlight a key universal challenge of calibrating spatially explicit, process‐based ecological models. Notably, the desire to reliably represent complex ecological processes in finely mapped landscapes necessarily generates a large number of parameters, which are challenging to calibrate with ecological and geographical data that are often noisy, biased, asynchronous and sometimes inaccurate. Purely data‐driven calibration can therefore result in unrealistic parameter values, despite appearing to improve model‐data agreement over initial expert opinion estimates. We therefore advocate a combined approach where data‐driven calibration and expert opinion are integrated into an iterative