1. Floral resources are known to be important in regulating wild pollinator populations and are therefore an important component of agri-environment and restoration schemes which aim to support pollinators and their associated services.However, the phenology of floral resources is often overlooked in these schemes -a factor which may be limiting their success.2. Our study characterizes and quantifies the phenology of nectar resources at the whole-farm scale on replicate farms in Southwestern UK throughout the flowering season. We quantify the corresponding nectar demands of a subset of common wild pollinators (bumblebees) to compare nectar supply and pollinator demand throughout the year, thereby identifying periods of supply-demand deficit.3. We record strong seasonal fluctuations in farmland nectar supplies, with two main peaks of nectar production (May and July) and a considerable "June Gap" in between. March and August/September are also periods of low nectar availability.4. Comparing the phenology of nectar supply with the phenology of bumblebee nectar demand reveals "hunger gaps" during March and much of August/September when supply is unlikely to meet demand. 5. Permanent pasture and woodland produced the greatest share of farmland nectar because of their large area; however, linear features such as hedgerows and field margins provided the greatest nectar per unit area. Fifty percent of total nectar was supplied by just three species (Allium ursinum, Cirsium arvense and Trifolium repens), but some less productive species (e.g. Hedera helix and Taraxacum agg.) were important in ensuring phenological continuity of nectar supply. 6. Synthesis and applications. By comparing the phenology of farmland nectar supply with the phenology of pollinator demand, we demonstrate that the timing of nectar supply may be as important as total nectar production in limiting farmland pollinator populations. Considering phenology in the design of agri-environment or restoration schemes is therefore likely to improve their suitability for pollinators. Plant species which flower during periods of resource deficit (early spring and late summer) should be prioritized in schemes which aim to conserve or restore K E Y W O R D S agri-environment, bumblebees, floral resources, flowering phenology, nectar, pollination, pollinator conservation, restoration | 1587 Journal of Applied Ecology TIMBERLAKE ET AL.

Floral resources are important in limiting pollinator populations, but they are often highly variable across time and space and the effect of this variation on pollinator population dynamics is not well understood. The phenology (timing) of floral resources is thought to be important in structuring pollinator populations, but few studies have directly investigated this. Our study quantifies the landscape composition, seasonal nectar and pollen supply and Bombus terrestris colony density of 12 farms in southwest UK to investigate how landscape composition influences the phenology of floral resources and how both these factors affect colony density. We use this information in a spatially explicit predictive model to estimate the effect of different farmland management scenarios on seasonal resource supplies and colony density. We find that farmland nectar supply during September is a strong predictor of B. terrestris colony density in the following year, explaining over half of all the variation in colony density; no other period of resource availability showed a significant association. Semi‐natural habitat cover was not a good proxy for nectar or pollen supply and showed no significant association with colony density. However, the proportional cover of gardens in the landscape was significantly associated with colony density. The predictive model results suggest that increasing the area of semi‐natural flowering habitat has limited effect on bumblebee populations. However, improving the quality of these habitats through Environmental Stewardship and other management options is predicted to reduce the late‐summer resource bottleneck and increase colony density. Synthesis and Applications. Our study demonstrates the importance of considering the phenology of resources, rather than just total resource availability, when designing measures to support pollinators. Late summer appears to be a resource bottleneck for bumblebees in UK farmland, and consequently management strategies which increase late‐summer nectar availability may be the most effective. These include mowing regimes to delay flowering of field margins until September, planting late‐flowering cover crops such as red clover and supporting late‐flowering wild plant species such as Hedera helix. Our results also suggest that rural gardens may play an important role in supporting farmland bumblebee populations.

Despite recent advances in understanding the role of biodiversity in ecosystem-service provision, the links between the health of ecosystem-service providers and human health remain more uncertain. During the past decade, an increasing number of studies have argued for the positive impacts of healthy pollinator communities (defined as functionally and genetically diverse species assemblages that are sustained over time) on human health. Here, we begin with a systematic review of these impacts, finding only two studies that concomitantly quantified aspects of pollinator health and human health. Next, we identify relevant research relating to four pathways linking pollinator health and human health: nutrition, medicine provisioning, mental health and environmental quality. These benefits are obtained through improved pollination of nutritious crops and an estimated approximately 28 000 animal-pollinated medicinal plants; the provisioning of pollinator-derived products such as honey; the maintenance of green spaces and biocultural landscapes that improve mental health; and cleaner air, water and food resulting from pollinator-centred initiatives to reduce agrochemical use. We suggest that pollinator diversity could be a proxy for the benefits that landscapes provide to human health. This article is part of the theme issue ‘Natural processes influencing pollinator health: from chemistry to landscapes’.

Smallholder farmers are some of the poorest and most food insecure people on Earth. Their high nutritional and economic reliance on home‐grown produce makes them particularly vulnerable to environmental stressors such as pollinator loss or climate change which threaten agricultural productivity. Improving smallholder agriculture in a way that is environmentally sustainable and resilient to climate change is a key challenge of the 21st century. Ecological intensification, whereby ecosystem services are managed to increase agricultural productivity, is a promising solution for smallholders. However, smallholder farms are complex socio‐ecological systems with a range of social, ecological and environmental factors interacting to influence ecosystem service provisioning. To truly understand the functioning of a smallholder farm and identify the most effective management options to support household food and nutrition security, a holistic, systems‐based understanding is required. In this paper, we propose a network approach to understand, visualise and model the complex interactions occurring among wild species, crops and people on smallholder farms. Specifically, we demonstrate how networks may be used to (a) identify wild species with a key role in supporting, delivering or increasing the resilience of an ecosystem service; (b) quantify the value of an ecosystem service in a way that is relevant to the food and nutrition security of smallholders; and (c) understand the social interactions that influence the management of shared ecosystem services. Using a case study based on data from rural Nepal, we demonstrate how this framework can be used to connect wild plants, pollinators and crops to key nutrients consumed by humans. This allows us to quantify the nutritional value of an ecosystem service and identify the wild plants and pollinators involved in its provision, as well as providing a framework to predict the effects of environmental change on human nutrition. Our framework identifies mechanistic links between ecosystem services and the nutrients consumed by smallholder farmers and highlights social factors that may influence the management of these services. Applying this framework to smallholder farms in a range of socio‐ecological contexts may provide new, sustainable and equitable solutions to smallholder food and nutrition security. A free Plain Language Summary can be found within the Supporting Information of this article.