April 27, 2018: Thesis defense by Laura Schneller, master's candidate in biological sciences

Invasion By the Non-native Plant Melilotus Albus (White Sweetclover) Affects Plant-pollinator Interactions in Boreal Alaska Thesis defense by Laura Schneller, M. Sci. Candidate, Biological Sciences

Friday, April 27, 1-2:30 p.m. ConocoPhillips Integrated Science Building, Room 120

Abstract: Invasive plants may have long-term impacts on plant-pollinator networks following their establishment. We examined the plant-pollinator network in boreal Alaska in response to Melilotus albus establishment, an invasive plant that is highly rewarding for a diversity of pollinators. We tested the hypothesis that the presence of M. albus draws pollinators away from native co-flowering species and results in a more simplified plant-pollinator network, with fewer links between species. We used two approaches: a non-manipulated comparison and a manipulative experiment of invaded and uninvaded sites to determine the effect of M. albus on the plant-pollinator network. We observed plant-pollinator interactions, and then compared pollinator visitation rates, richness, Shannon's Index of Diversity, and the network properties of connectance, nestedness, and links/species between sites with and without M. albus. Both non-manipulated and manipulated sites with M. albus had similar or higher rates of pollinator visitation to native plants than sites without M. albus. Richness and diversity of flower visitors was also higher in sites with M. albus than sites without M. albus. In addition, network complexity increased in sites with M. albus compared to sites without M. albus. These results did not support our hypothesis of negative impacts to visitation rates to native plants and simplification of plant-pollinator networks in the presence of the invasive plant; however, the results illustrate non-additive alterations in biotic interactions due to M. albus that may have other consequences for native plants and pollinators.

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