A Survey of Queen Anne's Lace on Nantucket and an Assessment of its Effect on Native Pollination, Year Two

Submitted in fulfillment of a 2016 Nantucket Biodiversity Initiative grant. For the peer reviewed publication of this work, refer to the related identifiers.

Daucus carota (Queen Anne’s Lace) is a non-native plant species that was introduced to North America from Europe, and its presence on Nantucket Island, Massachusetts has been documented since at least the nineteenth century. Research in other plant systems has investigated whether the presence of a non-native can affect native pollination, and the results have been mixed. A native may be negatively affected, may not be affected or may be positively affected by the presence of the non-native. In 2015 A population survey was performed on D. carota, and a pollinator observation study was performed on D. carota and a native species, Sericocarpus asteroides (Toothed White-top Aster). Pollinators were observed for three hours per day and five days each for the two species individually and both species cohabitating together. In 2016, additional populations were added to the D. carota population survey, and a removal treatment was performed on sites where both species cohabitate. On day one, the sites were observed as described, however, D. carota umbels were then removed from the site, and on the following day, pollinators were observed on S. asteroides. In addition, S. asteroides populations from a range of distances from D. carota were assayed for the presence and degree of heterospecific pollen. We had four hypotheses: 1) D. carota would be present across Nantucket Island; 2) The presence of D. carota would increase pollinator visitation rates and diversity indices on S. asteroides; 3) The removal of D. carota would restore pollinator visitation rates and diversity indices to those found on sites with only S. asteroides; 4) Higher levels of heterospecific pollination would be found in S. asteroides populations located close to D. carota. We found D. carota to be abundant across the island. While both plant species are generalist-pollinated, D. carota attracted 15 insect families and S. asteroides attracted only 8, with the majority being flies and bees. Each removal treatment received at least 50 % fewer pollinator visits after D. carota was removed, and the analysis on heterospecific pollination is currently on-going.