Poster Session I
Effects of Invasive Spotted Knapweed on Native Pollinator Foraging Behavior in Glacier National Park
Project Type
Poster
Faculty Mentor’s Full Name
Meredith Zettlemoyer
Faculty Mentor’s Department
Division of Biological and Biomedical Sciences
Additional Mentor
Asma Akter, asma.akter@mso.umt.edu
Abstract / Artist's Statement
Invasive species can often reduce native species’ performance. Competition for pollinators between native and invasive species can decrease pollination and reproduction of native plants. However, the effects of invasive species on competition for pollination may be complex. Invasive species that form large, dense populations with high numbers of flowers and copious rewards may attract more pollinators. In this case, invaders can either draw pollinators away from native plants or can increase pollinator visitation to native plants by attracting pollinators that otherwise would not have visited. Few studies examine how invasive species compete vs. facilitate pollinator services for native species. We investigated the impact of the abundance of a prolific invasive species, Centaurea stoebe (spotted knapweed), on plant diversity, pollinator diversity, and plant-pollinator network structure in an invaded grassland in Two Dog Flats, Glacier National Park. We recorded visitors across a gradient of spotted knapweed abundance at early and peak knapweed flowering, resulting in spatial and temporal variation in open knapweed flowers. Increasing knapweed flowers decreased plant and pollinator diversity. Increasing knapweed flower decreased pollinator visits and affected which pollinators visit. Hoverflies, including the invasive common drone fly, comprised most visits under high knapweed floral abundance while visits from common native pollinators like the Nearctic bumblebee declined. When knapweed floral abundance was low, solitary bees, wasps, and click beetles were more likely to visit. Pollinator networks became less complex at higher knapweed abundance, with decreased evenness and linkage density between plants and pollinators as knapweed dominated the interactions. These findings emphasize the importance of spotted knapweed management in maintaining native plant-pollinator networks.
Category
Life Sciences
Effects of Invasive Spotted Knapweed on Native Pollinator Foraging Behavior in Glacier National Park
UC South Ballroom
Invasive species can often reduce native species’ performance. Competition for pollinators between native and invasive species can decrease pollination and reproduction of native plants. However, the effects of invasive species on competition for pollination may be complex. Invasive species that form large, dense populations with high numbers of flowers and copious rewards may attract more pollinators. In this case, invaders can either draw pollinators away from native plants or can increase pollinator visitation to native plants by attracting pollinators that otherwise would not have visited. Few studies examine how invasive species compete vs. facilitate pollinator services for native species. We investigated the impact of the abundance of a prolific invasive species, Centaurea stoebe (spotted knapweed), on plant diversity, pollinator diversity, and plant-pollinator network structure in an invaded grassland in Two Dog Flats, Glacier National Park. We recorded visitors across a gradient of spotted knapweed abundance at early and peak knapweed flowering, resulting in spatial and temporal variation in open knapweed flowers. Increasing knapweed flowers decreased plant and pollinator diversity. Increasing knapweed flower decreased pollinator visits and affected which pollinators visit. Hoverflies, including the invasive common drone fly, comprised most visits under high knapweed floral abundance while visits from common native pollinators like the Nearctic bumblebee declined. When knapweed floral abundance was low, solitary bees, wasps, and click beetles were more likely to visit. Pollinator networks became less complex at higher knapweed abundance, with decreased evenness and linkage density between plants and pollinators as knapweed dominated the interactions. These findings emphasize the importance of spotted knapweed management in maintaining native plant-pollinator networks.