Population genetics of Phalaris arundinacea L. in a western United States wetland

Call Number:

Keywords:

Abstract:

Turnbull National Wildlife Refuge (henceforth Refuge) is a wetland complex located in east central Washington State. Phalaris arundinacea is an invasive grass species on the Refuge. It forms monotypic stands, reducing native plant diversity and can reproduce either sexually or from rhizomes and stem nodes. Due to the extreme density of P. arundinacea, we hypothesized that there was only one genetically distinct population of Phalaris arundinacea at the Refuge. The entire length and breadth of the refuge was sampled and leaf tissue was taken from each sample plant. Amplified Fragment Length Polymorphism was used to determine the presence or absence of genetic markers for each plant, and analysis using NTSYSpc, STRUCTURE, DISTRUCT and GenAlEx established the presence of 5 genetically distinct populations of Phalaris arundinacea at the Refuge. Out of 166 plants sampled only four were of clonal origin, indicating that this species’ reproduction on the Refuge is primarily sexual. Considering likely sources of this genetic variability, we identified the possibility of the species being planted by farmers relocating to this area prior to establishment of the refuge. At the time, the species was considered to be good forage for livestock. Further, refuge records indicate that the species was planted by refuge staff at least three times between 1945 and 1970, before it was observed to be invasive. Early cultivars available between those dates included both tetraploids and one hexaploid. Multiple introductions are considered to be a source of genetic variability allowing a species to adapt to a site and become invasive. We hypothesized that the Phalaris arundinacea plants on the Refuge could either be tetraploid, hexaploid or a mix. Through flow cytometry, we found that only tetraploids were present. The source of the genetic variability among these tetraploids remains unknown. The degree of variability discovered and the prevalence of sexual reproduction imply that this species has the genetic resources to adapt quickly to future changes in its environment and remain a management challenge on the refuge. Control strategies that limit seed production may be useful.

Notes:

Reference Code: U15CAN01IDUS

Full Citation: Canwell, S. 2015. Population genetics of Phalaris arundinacea L. in a western United States wetland. Unpublished dissertation, Washington State University, Pullman, WA. 44 pp.

Location: ELECTRONIC FILE BOTANY: UNTRACKED SPECIES: {Phalaris arundinacea}