A survey of pollinator assemblies in two contiguous Richmond, Virginia (U.S.A.), urban green spaces

The interactions between plants and their pollinators provide essential ecosystem services in support of the reproduction and propagation of flowering plants, as well as the nutritive support for pollinators and their offspring. Given the critical nature of these activities, coupled with exponential urban development and the concurrent, dramatic decline in pollinators worldwide, it has become increasingly important to evaluate the complex and specialized interactions between pollinators and their host plants. This includes assessing plant-pollinator interactions within urban green infrastructure. Here, we surveyed floral visitor interactions on nineteen summer-blooming plant species in two contiguous Richmond, Virginia, gardens. We observed 110 distinct flower visitor taxa, with the majority seen on four or fewer plant species. The most common flower visitors were bees, including Bombus impatiens, which was found on every plant surveyed. Although the flower visitor assemblages varied categorically among plant species, in total the two gardens hosted a broad range of generalist and specialist visitors. The results of this survey provide a regional and seasonal perspective on urban green space ecosystem dynamics.