Food for pollinators: Quantifying the nectar and pollen resources of urban flower meadows
Pollinator resources, Practical management
Evaluating 'pollinator friendly' urban flower meadow seed mixes for provision of food (nectar and pollen).
Type of content
Peer reviewed research paper
Data collection - ecological
The authors compared floral resources in two seed mixes and their associated weeds in four cities in the UK. The mixes used were Rigby Taylor’s ‘Rainbow Annual’ mix (14 species), and Emorsgate’s perennial ‘EN1F Special Pollen and Nectar Wildflowers’ mix (23 species).
They assessed the resources provided by the seed mixes. For nectar content, they excluded insects with netting for 24 hours, extracted nectar then sampled in the laboratory to work out the average nectar per floral unit (flower). They harvested pollen from a large sample of flowers using ‘sonication’ to find the pollen content per flower and then combined this with measures of floral longevity to estimate pollen available per day.
They considered the volume and continuity of the floral resources and discuss the potential to design seed mixes that avoid gaps in provision of food for pollinators.
Resources for pollinators
"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"