Low genetic diversity despite multiple introductions of the invasive plant species Impatiens glandulifera in Europe.

Jenny Hagenblad,Jörg Brunet,Isgard Lemke,Martin Hermy,Aurélien Jamoneau,Pieter De Frenne,Jan Plue,Kamal Prasad Acharya,Sara A O Cousins,Pervaiz A Dar,Bente Jessen Graae,Jennifer Hülskötter,Olivier Chabrerie,Zafar A Reshi,Annette Kolb,Martin Diekmann

doi:10.1186/s12863-015-0242-8

Abstract

BackgroundInvasive species can be a major threat to native biodiversity and the number of invasive plant species is increasing across the globe. Population genetic studies of invasive species can provide key insights into their invasion history and ensuing evolution, but also for their control. Here we genetically characterise populations of Impatiens glandulifera, an invasive plant in Europe that can have a major impact on native plant communities. We compared populations from the species’ native range in Kashmir, India, to those in its invaded range, along a latitudinal gradient in Europe. For comparison, the results from 39 other studies of genetic diversity in invasive species were collated.ResultsOur results suggest that I. glandulifera was established in the wild in Europe at least twice, from an area outside of our Kashmir study area. Our results further revealed that the genetic diversity in invasive populations of I. glandulifera is unusually low compared to native populations, in particular when compared to other invasive species. Genetic drift rather than mutation seems to have played a role in differentiating populations in Europe. We find evidence of limitations to local gene flow after introduction to Europe, but somewhat less restrictions in the native range. I. glandulifera populations with significant inbreeding were only found in the species’ native range and invasive species in general showed no increase in inbreeding upon leaving their native ranges. In Europe we detect cases of migration between distantly located populations. Human activities therefore seem to, at least partially, have facilitated not only introductions, but also further spread of I. glandulifera across Europe.ConclusionsAlthough multiple introductions will facilitate the retention of genetic diversity in invasive ranges, widespread invasive species can remain genetically relatively invariant also after multiple introductions. Phenotypic plasticity may therefore be an important component of the successful spread of Impatiens glandulifera across Europe.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0242-8) contains supplementary material, which is available to authorized users.

Highlights

Introduction history ofI. glandulifera The presence of I. glandulifera in Europe was reported from gradually more northern locations, suggesting a progressive northward spread of the species during the early 20th century
Genotyping success and presence of null alleles A final dataset of 378 individuals genotyped for nine markers was used to explore the population genetics of I. glandulifera
Individuals from 10 populations, some located within the same municipality, along the species’ north – south distribution in Europe were genotyped for eleven microsatellite markers and compared with individuals from three populations from Kashmir in the species’ native range (Table 1, Fig. 1)

Summary

Introduction

Introduction history ofI. glandulifera The presence of I. glandulifera in Europe was reported from gradually more northern locations (see e.g. [37, 47, 67, 73, 97]), suggesting a progressive northward spread of the species during the early 20th century. [37, 47, 67, 73, 97]), suggesting a progressive northward spread of the species during the early 20th century In such a scenario latitudinal effects on different measures of the distribution of genetic diversity could be expected as the result of successive colonisation events. Being just a subset of the species-wide gene pool, possibly suffering severe loss of genetic diversity upon the invasion [4, 66], they are able to thrive in a novel environment and thereby provide useful study systems for responses to rapid environmental changes [21, 39]. Loss of genetic diversity is expected upon colonisation of new areas, it has been suggested that high genetic diversity, resulting from multiple introductions, could be what allows a species to become invasive [69]

Objectives

Methods

Results

Discussion

Conclusion