title: Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows.
abstract: Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many 'pollinator-friendly' seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes.
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, Charlotte Auerbach Road, Edinburgh EH9 3JT, United Kingdom.
authors.forename: Damien M
authors.initials: DM
authors.lastname: Hicks
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, Charlotte Auerbach Road, Edinburgh EH9 3JT, United Kingdom.|Earth and Life Institute - Agronomy, Université catholique de Louvain, Place Croix du Sud 2, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Ouvrard
authors.affiliation: School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQUG, United Kingdom.|Cabot Institute, University of Bristol, Woodland Road, Bristol, BS8 1UJ, United Kingdom.
authors.forename: Katherine C R
authors.initials: KC
authors.lastname: Baldock
authors.affiliation: School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQUG, United Kingdom.|Collegium Sciences et Techniques, EA 1207 LBLGC, Université d'Orléans, 45067, Orléans, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Baude
authors.affiliation: School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Goddard
authors.affiliation: School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.
authors.forename: William E
authors.initials: WE
authors.lastname: Kunin
authors.affiliation: School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQUG, United Kingdom.|Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, RG6 6AR, United Kingdom.
authors.forename: Nadine
authors.initials: N
authors.lastname: Mitschunas
authors.affiliation: School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQUG, United Kingdom.|Cabot Institute, University of Bristol, Woodland Road, Bristol, BS8 1UJ, United Kingdom.
authors.forename: Jane
authors.initials: J
authors.lastname: Memmott
authors.affiliation: School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQUG, United Kingdom.
authors.forename: Helen
authors.initials: H
authors.lastname: Morse
authors.affiliation: School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.
authors.forename: Maria
authors.initials: M
authors.lastname: Nikolitsi
authors.affiliation: School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQUG, United Kingdom.
authors.forename: Lynne M
authors.initials: LM
authors.lastname: Osgathorpe
authors.affiliation: Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, RG6 6AR, United Kingdom.
authors.forename: Simon G
authors.initials: SG
authors.lastname: Potts
authors.affiliation: School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.
authors.forename: Kirsty M
authors.initials: KM
authors.lastname: Robertson
authors.affiliation: Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, Reading, RG6 6AR, United Kingdom.
authors.forename: Anna V
authors.initials: AV
authors.lastname: Scott
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, Charlotte Auerbach Road, Edinburgh EH9 3JT, United Kingdom.|Royal Society for the Protection of Birds, Gola Rainforest National Park, Kenema, Sierra Leone.
authors.forename: Frazer
authors.initials: F
authors.lastname: Sinclair
authors.affiliation: Institute of Science & the Environment, The University of Worcester, Henwick Grove, Worcester, WR2 6AJ, United Kingdom.
authors.forename: Duncan B
authors.initials: DB
authors.lastname: Westbury
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Kings Buildings, Charlotte Auerbach Road, Edinburgh EH9 3JT, United Kingdom.
authors.forename: Graham N
authors.initials: GN
authors.lastname: Stone
mesh_terms: D000818:Animals; D001516:Bees; D044822:Biodiversity; D017753:Ecosystem; D035264:Flowers; D005502:Food; D057048:Plant Nectar; D011058:Pollen; D054817:Pollination; D012621:Seasons; D012639:Seeds
chemical_list: D057048:Plant Nectar