Invasive non-native plants have been found to reduce pollinator abundance and diversity, and disrupt pollinator services to some native plants, which could reduce seed production. Although our knowledge is still limited on the effects of invasive plants on pollinator abundance and diversity, and pollination of native plants, several studies have been conducted that answer some of those questions. Results of these studies will further our understanding of the influence of plant-pollinator interactions on native plant communities threatened by invasive plants.
The following information briefly summarizes some of the research on the effects of invasive plants on pollinators.
Temporal- and density-dependent impacts of an invasive plant on pollinators and pollination services to a native plant
Herron-Sweet C, E Lehnhoff, L Burkle, J Littlefield, and J Mangold. Ecosphere. 2016. Volume 7, Issue 2.
This research studied the direct and indirect impacts of spotted knapweed (Centaurea stoebe) on pollinators and pollination services on a native plant. Two studies were conducted to investigate how the presence and density of spotted knapweed influenced local pollinator abundance, richness, community composition and visitation patterns over the flowering season, as well as the reproduction of a co-flowering native plant, hairy golden aster (Heterotheca villosa). Results of the study suggest that keeping spotted knapweed at low densities may be sufficient to prevent negative effects on pollinator-dependent native plant reproduction and may even be beneficial to some pollinators by providing floral resources later into summer. Furthermore, competition for pollinators does not appear to be a mechanism by which spotted knapweed invades a native plant community, at least not in the early stages of invasion (i.e. low densities of spotted knapweed). In locations where spotted knapweed is too abundant to eradicate, maintaining ecologically tolerable thresholds is a reasonable management goal, which may come as good news to land managers faced with this widespread, persistent species. [ CLICK HERE FOR MORE INFO ]
The invasive Lespedeza cuneata attracts more insect pollinators than native congeners in tallgrass prairie with variable impacts.
Woods TM, JL Jonas, and CJ Ferguson. Biological Invasions. 2012. 14:1045-1059.
This study investigated plant-pollinator dynamics by comparing the invasive Lespedeza cuneata and three native congeners. Results showed that floral density in L. cuneata was at least twenty times higher than in the native species and likely saturated the pollinator community. The common honeybee was a primary visitor to the invasive plant species, yet was never observed on the native Lespedeza species. [ READ MORE ]
Removing an exotic shrub from riparian forests increases butterfly abundance and diversity
JL Hanula, S Horn. Forest Ecology and Management. Volume 262, Issue 4, 15 August 2011, Pages 674–680.
Removing Chinese privet from riparian forests in the southeastern United States greatly improved forest habitats for butterflies and evidence suggests that butterfly communities in other temperate forests could benefit from removal of extensive shrub layers dominated by a single species. [ READ MORE ]
Wild pollinator communities are negatively affected by invasion of alien goldenrods in grassland landscapes (Poland)
D Moron´, M Lenda, P Skórka , H Szentgyörgyi , J Settele, M Woyciechowski. Biological Conservation. 142 (2009) 1322–1332.
The study emphasizes the urgent need to develop specific protection plans for wild pollinators in habitats threatened by foreign plants. Note to readers: This research article from Poland and concerns Solidago canadensis and S. gigantea, both native to most of North America. These two species are alien to Europe where they were introduced in the 1600s. [ READ MORE ]
Ranking Lepidopteran Use of Native Versus Introduced Plants
DW Tallamy and KJ Shropshirel. Conservation Biology. Volume 23, Issue 4, Pages 941–947, August 2009.
Results of the study showed that woody plants supported significantly more species of moths and butterflies than herbaceous plants, native plants supported more species than introduced plants, and native woody plants with ornamental value supported more Lepidoptera species than introduced woody ornamentals. [ READ MORE ]
Competition for Pollination between an Invasive Species (Purple loosestrife) and a native congener.
Brown, BJ et al. Ecology. 83, 2328–2336. 2002
Studies found that the invasive purple loosestrife (Lythrum salicaria) significantly reduced both pollinator visitation and seed set in native winged loosestrife ( L. alatum). Results suggest that invasive plants may be an even greater threat to natives than previously thought. [ READ MORE ]
The Pollinator Partnership is the largest organization in the world dedicated exclusively to the protection and promotion of pollinators and their ecosystems.
DID YOU KNOW?
Invasive plants can be selectively controlled and maintain desirable forb (wildflowers) diversity for pollinators and other insects. For example, common milkweed (Asclepias syriaca) is an important food plant for the monarch butterfly and is tolerant Milestone. Information on tolerance of desirable forbs to Milestone is available HERE.
Research on pollinator and invasive plant interactions
Risks to pollinators and pollination from invasive alien species
Vanbergen, A.J., A Espindola, and M.A. Aizen. Nature Ecology & Evolution 2, 16–25 (2018)
Invasive alien species modify pollinator biodiversity and the services they provide that underpin ecosystem function and human well-being. This article highlights evolutionary implications for pollination from invasive alien species, and identify future research directions, key messages and options for decision-making. [READ MORE]
Bjerknes A, Ø Totland, SJ Hegland, and A Nielsen. 2007. Do alien plant invasions really affect pollination success in native plant species? Biological Conservation 138:1-12. Accessed 29 April 2015. [READ MORE]
Chrobock T, P Winiger, M Fischer, and M VanKleunen. 2013. The cobblers stick to their lasts: pollinators prefer native over alien plant species in a multi-species experiment. Biological Invasions 15:2577-2588. Accessed 29 April 2015. [ READ MORE]
Jacobson A, B Pedro, and A Traveset. 2009. Competition for pollinators between invasive and native plants. Effects of special scale of investigation (Note). EcoScience 16: 138-141. Accessed 29 April 2015. [READ MORE]