Are Invasive Genotypes Superior? An Experimental Approach Using Native and Invasive Genotypes of the Invasive Grass &amp;lt;i&amp;gt;Phalaris Arundinacea&amp;lt;/i&amp;gt;

Jane Molofsky,Tadas Bitinas,Eric Imbert,Sébastien Lavergne,Alexandra R Collins

doi:10.4236/oje.2017.72010

Abstract

The admixture and recombination of individuals from the native range into a new range may lead to the production of invasive genotypes that have higher fitness and wider climatic tolerances than the native genotypes. In this paper, we compare the survival and growth of native EU and invasive NA genotypes when planted back into the native EU range near where the EU genotypes were collected. We test this hypothesis using the invasive wetland grass Phalaris arundinacea. If invasive genotypes have evolved to have higher survival and growth, then they should outperform the native EU genotypes under field conditions that are better suited to the EU genotypes. Individual plants of the wetland grass, Phalaris arundinacea collected from native Europe (Czech Republic (CZ) and France (FR)) and North America (Vermont (VT) and North Carolina (NC)) were planted into common gardens in Trebon, Czech Republic (49.0042°N, 14.7721°E) and Moussac, France (43.9808°N, 4.2241°E). Invasive genotypes from North Carolina (NC) survived as well or better than native genotypes in both the Trebon and Moussac garden. Additionally, invasive NC genotypes suffered higher herbivore damage than native genotypes but their growth and survival were not significantly different than genotypes from the other re-gions. A companion field experiment that simulated biomass removal through grazing indicated that invasive NC genotypes recovered faster following grazing than genotypes from other regions. Our results suggest that not all invasive genotypes are superior and regional differences in aggressiveness between invasive genotypes are as great as differences between individuals from native and invasive populations. Introduction of genotypes leading to invasion depends upon the environmental conditions and the suitability of the climate for the introduced individuals.

Highlights

An introduced species may behave invasively in the new range because it already possesses traits that confer invasiveness [1] [2], or alternatively, it may evolve invasiveness in situ in the new range [3] [4] [5] [6]
Individual plants of the wetland grass, Phalaris arundinacea collected from native Europe (Czech Republic (CZ) and France (FR)) and North America (Vermont (VT) and North Carolina (NC)) were planted into common gardens in Trebon, Czech Republic (49.0042 ̊N, 14.7721 ̊E) and Moussac, France (43.9808 ̊N, 4.2241 ̊E)
Multiple introductions may result in the admixture of genomes that have never come into contact with each other creating novel, invasive genotypes that may express different traits and enhanced fitness [11] [12] [13] [14]

Summary

Introduction

An introduced species may behave invasively in the new range because it already possesses traits that confer invasiveness [1] [2], or alternatively, it may evolve invasiveness in situ in the new range [3] [4] [5] [6]. A successful introduction can depend upon the relationship between the introduced individuals and the new environment. Introduced individuals may have different climatic tolerances than their native counterparts [15] and/or wider climatic tolerances [16] [17] and this may contribute to their success. Testing whether invasive genotypes have a wider climatic tolerance than native genotypes requires planting clones of both known native and invasive genotypes in their home climate and in a different climate to test whether invasive genotypes have greater ability to survive and grow under a new climatic condition

Methods

Results

Conclusion