A comprehensive dataset on pollinator diversity, visitation rates, individual-based traits, and pollination success across four plant species in an urban garden experiment

Merin Reji Chacko , Marco Moretti, David Johannes Frey

This dataset presents flower visitation frequency, pollinator richness, and direct measures of pollination success for four focal plant species from a field experiment in 24 home gardens in the city of Zurich, Switzerland. The home gardens were selected to vary independently in local flowering species richness and the proportion of impervious surface in a 500-m radius around the garden, a common proxy for urban intensity and associated habitat loss. We used a phytometer species approach with the following four insect-pollinated plant species: wild carrot (Daucus carota L.), radish (Raphanus sativus L.), common sainfoin (Onobrychis viciifolia Scop.) and common comfrey (Symphytum officinale L.).
We provide the species richness and hourly visitation frequency of 167 flower visitor taxa across multiple taxonomic groups (bees, wasps, beetles, and hoverflies) from multiple sampling dates across the full flowering period of the phytometer species. We collected and identified 5,794 individuals, of which the vast majority (99.5%) were identified to the species or genus level. We provide several functional trait measurements at the individual level. For bees, we measured intertegular distance and proboscis length (the combined lengths of prementum and glossa); for the other taxa, we measured forewing length and the lengths of the labellum, prementum, and fulcrum. We additionally provide seed and/or fruit set, a direct measure of reproductive success for all phytometer plants.
Further datasets for these gardens exist, linking soil and soil arthropod diversity data, bird predation data, and plant diversity and properties sampled during the same period. This dataset enables further investigations into the composition of novel anthropogenic pollinator communities, such as analyses comparing multiple cities. The fine temporal resolution of flower visitor frequency additionally provides the opportunity to conduct time series analyses of diurnal pollinator communities across environmental gradients.