Biological Invasions

, Volume 16, Issue 10, pp 2147–2161 | Cite as

Evaluating hybridization as a potential facilitator of successful cogongrass (Imperata cylindrica) invasion in Florida, USA

  • Rima D. LucardiEmail author
  • Lisa E. Wallace
  • Gary N. Ervin
Original Paper


Interspecific hybridization is cited as one potential mechanism for increased invasiveness, particularly among some grass species. In the southeastern United States, the successful invasion of cogongrass (Imperata cylindrica) has sometimes been attributed to hybridization with the previously naturalized Imperata brasiliensis. This research aimed to determine whether genetic signals are consistent with these two species having experienced interspecific hybridization in Florida (USA), where it has been proposed that such an event facilitated cogongrass invasion across the region. Individuals of invasive I. cylindrica populations (n = 66) were sampled broadly from the state, and I. brasiliensis (n = 63) individuals were sampled from expertly identified and vouchered populations in Miami-Dade County. Genetic analysis utilized amplified fragment length polymorphisms in sampled individuals, and failed to detect significant genetic differentiation between the two species. Analysis of molecular variance partitioned the majority of detected variation within populations (86 %), while only 8 % was significantly partitioned between I. cylindrica and I. brasiliensis (FST = 0.135, P < 0.001). Both STRUCTURE analysis and principal coordinates analysis strongly indicated the presence of a single genetic group across the sampled populations. Hybrid analysis furthermore failed to support interspecific hybridization. Florida populations thus are suggested to share genetic parent material(s) and/or have experienced substantial admixture across the state. Therefore, this study suggests Imperata populations in South Florida that are currently considered to be I. brasiliensis are not genetically distinct from I. cylindrica, and regional cogongrass invasion likely was not facilitated by previously postulated interspecific hybridization.


AFLP Genetic diversity Grasses Hybridization Invasive species Poaceae 



We extend our sincere appreciation to Chris Matson and Debi Tharp, at the Disney Wilderness Preserve of The Nature Conservancy, and Keith Bradley, of the Institute for Regional Conservation, for their assistance with sampling tissues. We thank B.A. Counterman, D.C. Outlaw (Department of Biological Sciences, Mississippi State University), C.T. Bryson (retired, U.S. Department of Agriculture -Agriculture Research Service, Stoneville, MS), and Jake Walker (Arkansas Research Center) for reviewing an earlier version of this manuscript. Two anonymous reviewers provided helpful critiques of an earlier version of this manuscript. This research was supported in part by grants from the United States Geological Survey Biological Resources Discipline (#04HQAG0135) and the United States Department of Agriculture (2006-03613 and 2008-35320-18679) to GNE.


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Copyright information

© Springer International Publishing Switzerland (outside the USA) 2014

Authors and Affiliations

  • Rima D. Lucardi
    • 1
    • 2
    Email author
  • Lisa E. Wallace
    • 1
  • Gary N. Ervin
    • 1
  1. 1.Department of Biological SciencesMississippi State UniversityStarkvilleUSA
  2. 2.Forest ServiceU.S. Department of Agriculture, Southern Research StationAthensUSA

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