Biological Invasions

, Volume 18, Issue 7, pp 2067–2075 | Cite as

An unusual case of seed dispersal in an invasive aquatic; yellow flag iris (Iris pseudacorus)

  • John F. Gaskin
  • Monica L. Pokorny
  • Jane M. Mangold
Original Paper


Invasive aquatic plants typically reproduce vegetatively, but there have been conflicting hypotheses of invasive aquatic yellow flag iris dispersing primarily by seed versus rhizome fragmentation. We performed genetic analysis of 20 aquatic yellow flag iris populations across the Pacific Northwest, USA, with leaf tissue taken from plants between 2 and 5 m apart. We found 167 unique genotypes in 171 plants, and we never found genetically identical plants from different populations. We found that 99.1 % of seed is viable. Our results support that this obligately outcrossing invasive disperses almost entirely by seed, not rhizome fragmentation. We found no significant relationship between genetic and geographic distance across the Pacific Northwest, suggesting recent long distance dispersal and/or multiple founding events. Bayesian analysis shows the presence of two major genotypic clusters within our collections which also suggests more than one distinct genetic source for the invasion. These processes have led to genetically distinct populations that can be geographically close. Our findings are unusual for an aquatic invasive, and inform yellow flag iris managers of two things: (1) to limit dispersal, development of mature seed in the field should be prevented; and (2) if classical biological control is proposed, an agent guild that limits seed production would be effective for managing most dispersal.


Invasive aquatic plant Iris pseudacorus Reproduction Yellow flag iris AFLP 



This research was made possible in part by funding from the Bureau of Land Management (Montana, South and North Dakota) Billings Office. Thanks to K. Mann and J. Lassey for generating AFLP data.

Supplementary material

10530_2016_1151_MOESM1_ESM.xlsx (86 kb)
Supplementary material 1 (XLSX 86 kb)


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Copyright information

© Springer International Publishing Switzerland (outside the USA) 2016

Authors and Affiliations

  • John F. Gaskin
    • 1
  • Monica L. Pokorny
    • 2
  • Jane M. Mangold
    • 2
  1. 1.USDA ARSSidneyUSA
  2. 2.Department of Land Resources and Environmental SciencesMontana State UniversityBozemanUSA

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