DOI: 10.5061/dryad.31f7ph7
title: Data from: Monitoring insect pollinators and flower visitation: the effectiveness and feasibility of different survey methods

description: 1. 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. Standardised protocols are urgently needed,
 alongside a better understanding of how different methods and recorders
 (data collectors) influence estimates of pollinator abundance and
 diversity. 2. We compared two common methods for sampling wild pollinating
 insects (solitary bees, bumblebees and hoverflies), pan traps and
 transects, in surveys of 1km 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. 3. 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 greater numbers of individual
 bumblebees, but fewer species. 4. 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 is almost commensurate with pan trapping. 5. 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. 6. 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 standardised, large-scale monitoring of
 pollinating insects.
description: Crop pollinator pan
 trap, timed observation and transect dataThis dataset contains
 abundance data for common groups of insect pollinators collected from 6
 sampling locations in 8 conventional fields of apple, strawberry and field
 beans. Apple orchards were located in Kent (Southern England), field beans
 fields were located in Berkshire and Oxfordshire (Southern England) and
 strawberry field were in Yorkshire (Northern England). These data were
 collected using 3 different methods. Pan traps: 6 yellow, white and blue
 water trap stations were set up and left for between 8 and 24 hours.
 Transects: Each transect involved walking 50m of crop over 10 minutes
 recording all flower visitors observed in a moving window of fixed area
 alongside the recorder. Stationary observation: All floral visits made by
 pollinators in a fixed area were recorded for 10 minutes. The number of
 open flowers in the observation area was also recorded. Each method was
 carried out simultaneously, over several rounds during crop flowering and
 only in dry conditions, in temperature 15 oC or greater with no more than
 light wind.CropPollinator_Pan_Transect_StationaryObservations_2011.xlsx