Similarly Potts et al. (2009) demonstrated benefits to bumblebee abundance from management similar to EG1 (under sown spring cereals) however expert pollinator habitat benefit (PHB—Eq. 1) score was low for this option. These trends may stem from the broader taxonomic scope of the panel than previous studies. For many options however, expert opinion has little or no direct empirical backing.

In particular options EB8-10 (combined hedge and ditch management), and this website EC24/25 (Hedgerow tree buffer strips on cultivated/grassland), have no direct studies for the benefits to pollinators but are likely to provide high quality nesting resources for a broad range of species on otherwise crop/grass dominated land. While lacking the rigors of primary ecological research, this study demonstrates that expert opinion can be used to provide an insight into the benefits of options within ELS to specific taxa and ecosystem services. Indeed many of the highest rated options in this study are now recommended for improving habitat for pollinators in the current, 4th edition of the ELS handbook (Natural England 2013b). However, the range of possible values of PHB that experts were able to give may impact upon the habitat quality (HQ—Eq. 2) values and subsequent analysis by making the differences in benefits between options more coarse. Furthermore this also assumes

AZD3965 purchase no variation in quality of option implementation either by management, or by spatial (proximity to source habitat) or temporal factors (succession), preventing a more accurate estimate of long term benefits within landscapes. Altering the scale of response (e.g. to a continuous 0–1 scale) to better emphasise differences in benefits between options may allow more precise quality appraisals. Alternatively, experts could give confidence intervals along the same scales to represent variation in option management or synergies with other options. Costs and benefits of model applications Using MRIP three models, PHB scores were translated into new compositions of options based on

a 2012 baseline. The total costs of restructuring ELS towards a composition reflecting the benefits to pollinators were then estimated, using prior data, at £91.4–£44.8 M. This increase of £53.9–£12.4 M over the baseline (£32.2 M) reduces the benefits of ELS payments to farmers relative to their costs by up to 52 %. Nonetheless, these private costs are substantially below the estimated value of crop production added by pollination services (£430 M—Smith et al. 2011). If the value of ELS payments is added, representing society’s expenditure on incentivising these options, total costs are estimated at £308.7–£162.5 M, with private costs rising at a faster rate than public benefits. The benefits of these options mixes, in terms of total quantitative habitat quality scores, varied strongly between models but all three result in an increase in overall habitat quality.