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The status of pollinating insects is of international concern, but knowledge of the magnitude and extent of declines is limited by a lack of systematic monitoring. Standardized protocols are urgently needed, alongside a better understanding of how different methods and recorders (data collectors) influence estimates of pollinator abundance and diversity.We compared two common methods for sampling wild pollinating insects (solitary bees, bumblebees and hoverflies), pan traps and transects, in surveys of 1 km countryside squares (agricultural and semi‐natural habitats) and flowering crop fields across Great Britain, including the influence of local floral resources (nectar sugar availability or crop flower density) on the insects sampled. Further, we compared the performance of recorders with differing expertise (non‐specialist research staff, taxonomic experts and non‐expert volunteers) in applying methods.Pan traps and transects produced compositionally distinct samples of pollinator communities. In the wider countryside, pan traps sampled more species of solitary bee and hoverfly. In flowering crops, transects recorded a greater number of individual bumblebees, but fewer species.Across all taxonomic groups and countryside and crop samples, transects generally had lower rates of species accumulation per individual collected than pan traps. This demonstrates that differences between methods in estimating richness are not due to sampling effort alone. However, recorders possessing greater taxonomic expertise can produce species accumulation data from transects that are almost commensurate with pan trapping.The abundance and species richness of pollinators (except solitary bees) on transects in the wider countryside was positively related to the availability of estimated nectar sugar. In crops, pollinator abundance responses to flower densities were idiosyncratic according to crop type, but overall the response was positive and negative for transects and pan traps, respectively.Given these taxonomic and context‐specific differences in method performance, we assess their suitability for monitoring pollinating insect communities and pollination services. We discuss the relevance of these findings within the context of achieving standardized, large‐scale monitoring of pollinating insects. [ABSTRACT FROM AUTHOR]

Landscape heterogeneity in floral communities has the potential to modify pollinator behavior. Pollinator foraging varies with the diversity, abundance, and spatial configuration of floral resources. However, the implications of this variation for pollen transfer and ultimately the reproductive success of insect pollinated plants remains unclear, especially for species which are rare or isolated in the landscape. We used a landscape-scale experiment, coupled with microsatellite genotyping, to explore how the floral richness of habitats affected pollinator behavior and pollination effectiveness. Small arrays of the partially self-compatible plant Californian poppy ( Eschscholzia californica) were introduced across a landscape gradient to simulate rare, spatially isolated populations. The effects on pollinator activity, outcrossing, and plant reproduction were measured. In florally rich habitats, we found reduced pollen movement between plants, leading to fewer long-distance pollination events, lower plant outcrossing, and a higher incidence of pollen limitation. This pattern indicates a potential reduction in per capita pollinator visitation, as suggested by the lower activity densities and richness of pollinators observed within florally rich habitats. In addition, seed production reduced by a factor of 1.8 in plants within florally rich habitats and progeny germination reduced by a factor of 1.2. We show this to be a consequence of self-fertilization within the partially self-compatible plant, E. californica. These findings indicate that locally rare plants are at a competitive disadvantage within florally rich habitats because neighboring plant species disrupt conspecific mating by co-opting pollinators. Ultimately, this Allee effect may play an important role in determining the long-term persistence of rarer plants in the landscape, both in terms of seed production and viability. Community context therefore requires consideration when designing and implementing conservation management for plants which are comparatively rare in the landscape. [ABSTRACT FROM AUTHOR]

Many flowering plant species have a facultative or obligate dependence on insect pollination for reproductive success. Anthropogenic disturbance may alter these species interactions, but the extent to which structural changes to plant-pollinator networks affect plant species mating systems is not well understood., We used long-term livestock grazing of a birch wood ecosystem to test whether disturbance of this semi-natural habitat altered floral resources, the structure of plant-insect visitation networks and the mating system of a focal plant species, Cirsium palustre., Grazed habitat had a higher species richness of floral resources for pollinators. Visitation networks in grazed habitats were larger, more diverse, with an increase in the number of pollinators per plant species. Controlling for sampling effects, however, showed networks in grazed habitats were less nested and revealed a positive correlation between network connectance and floral species richness., Network connectance was negatively related to C. palustre outcrossing rate within grazed and ungrazed sites. However, on average, the effects of grazing, including greater mean connectance, produced higher overall outcrossing rates and more pollen donors compared with ungrazed habitat. The number of different pollen donors, spatial genetic structure and mating among close relatives were all correlated with greater extent of suitable C. palustre habitat in the landscape, consistent with the effects of increasing plant population size but limited seed dispersal., Pre-adaptation of C. palustre to disturbance coupled with a preponderance of highly dispersive flies attracted to the greater food resources in grazed habitat is a likely mechanism underpinning this increased pollen transport., Habitat modification by long-term mammalian grazing fundamentally shifted visitation network structure and the state of a plant mating system, indicating how ecosystem disturbance can cascade across levels of biological organization through altered interspecific interactions. Cirsium palustre retains flexibility to bias reproduction towards selfing where pollen donor diversity is limited; such reproductive flexibility may be an important mechanism structuring plant populations in human-modified landscapes. [ABSTRACT FROM AUTHOR]

Invertebrates supporting natural pest control and pollination ecosystem services are crucial to world-wide crop production. Understanding national patterns in the spatial structure of natural pest control and pollination can be used to promote effective crop management and contribute to long-term food security., We mapped the species richness and functional diversity of ground beetles and bees to provide surrogate measures of natural pest control and pollination for Great Britain. Functional diversity represents the value and range of morphological and behavioural traits that support ecosystem services. We modelled the rate at which functional diversity collapsed in response to species extinctions to provide an index of functional redundancy., Deficits in functional diversity for both pest control and pollination were found in areas of high arable crop production. Ground beetle functional redundancy was positively correlated with the landscape cover of semi-natural habitats where extinctions were ordered by body size and dispersal ability. For bees, functional redundancy showed a weak positive correlation with semi-natural habitat cover where species extinctions were ordered by feeding specialization., Synthesis and applications. Increasingly, evidence suggests that functionally diverse assemblages of ground beetles and bees may be a key element to strategies that aim to support pollination and natural pest control in crops. If deficits in both functional diversity and redundancy in areas of high crop production are to be reversed, then targeted implementation of agri-environment schemes that establish semi-natural habitat may provide a policy mechanism for supporting these ecosystem services. [ABSTRACT FROM AUTHOR]

Habitat heterogeneity contributes to the maintenance of diversity, but the extent that landscape-scale rather than local-scale heterogeneity influences the diversity of soil invertebrates—species with small range sizes—is less clear. Using a Scottish habitat heterogeneity gradient we correlated Collembola and lumbricid worm species richness and abundance with different elements (forest cover, habitat richness and patchiness) and qualities (plant species richness, soil variables) of habitat heterogeneity, at landscape (1 km2) and local (up to 200 m2) scales. Soil fauna assemblages showed considerable turnover in species composition along this habitat heterogeneity gradient. Soil fauna species richness and turnover was greatest in landscapes that were a mosaic of habitats. Soil fauna diversity was hump-shaped along a gradient of forest cover, peaking where there was a mixture of forest and open habitats in the landscape. Landscape-scale habitat richness was positively correlated with lumbricid diversity, while Collembola and lumbricid abundances were negatively and positively related to landscape spatial patchiness. Furthermore, soil fauna diversity was positively correlated with plant diversity, which in turn peaked in the sites that were a mosaic of forest and open habitat patches. There was less evidence that local-scale habitat variables (habitat richness, tree cover, plant species richness, litter cover, soil pH, depth of organic horizon) affected soil fauna diversity: Collembola diversity was independent of all these measures, while lumbricid diversity positively and negatively correlated with vascular plant species richness and tree canopy density. Landscape-scale habitat heterogeneity affects soil diversity regardless of taxon, while the influence of habitat heterogeneity at local scales is dependent on taxon identity, and hence ecological traits, e.g. body size. Landscape-scale habitat heterogeneity by providing different niches and refuges, together with passive dispersal and population patch dynamics, positively contributes to soil faunal diversity. [ABSTRACT FROM AUTHOR]

Summary: Changes in Collembola richness and diversity along a land-use intensity gradient were studied in eight European countries (Portugal, Spain, France, Switzerland, Hungary, UK, Ireland and Finland). In each country a set of six 1km2 land-use units (LUUs) were selected forming a gradient ranging from natural forest to agricultural dominated landscapes, passing through mixed-use ones. In addition to data on Collembola, detailed information regarding landscape diversity and structure was collected for each LUU. A total of 47,774 individuals were identified from 281 species. Collembola reacted not only to changes in the diversity of the landscape, but also to the composition of that diversity and the area occupied by each land-use type at each LUU. Although species richness patterns were not concordant among the different countries, the total number of species per LUU (landscape richness) was generally higher in natural forests and mixed-used landscapes, and lower in agricultural dominated landscapes. Moreover, high richness and diversity of Collembola at each LUU were associated with a diverse landscape structure, both in terms of number of patches and patch richness. Despite this comparable species richness between mixed-use landscapes and those dominated by natural forests, average species richness on forested areas (local richness) decreased along the gradient, showing that forest patches on mixed-use landscapes support a lower richness than in landscapes dominated by forest. This aspect is important when addressing the role of native forests in structuring biodiversity in disturbed and fragmented landscapes. Although a diverse landscape can support a high biodiversity, the results suggest that intensive fragmentation should be avoided with the risk of collapsing local species richness with the consequent result for regional biodiversity. [Copyright &y& Elsevier]