Genetic status of the endangered plant species Gladiolus palustris in the western part of its distribution area

Laura Daco,Serge Muller,Tiphaine Maurice,Guy Colling,Julie Rossa

doi:10.1007/s10592-019-01213-0

Abstract

Many endangered plant species suffer from the effects of ongoing fragmentation of their populations leading to a loss of genetic diversity through genetic drift. In addition, populations of rare plants may also be affected by hybridization with other plant species. We studied the genetic population structure of populations of the endangered Gladiolus palustris in the western limit of its distribution area using AFLP markers. In addition, we clarified the taxonomic status of populations where hybridization with the closely related G. imbricatus was suspected based on morphology by sequencing the ITS region of the nuclear ribosomal DNA as well as two regions of the chloroplast DNA. Our analysis of the genetic population structure of G. palustris revealed a strong differentiation among geographical regions, which was much higher than the differentiation among populations within regions. Most populations retained a considerable amount of genetic variation. To counteract the future loss of genetic diversity through drift, we recommend using the largest populations per region as seed source to increase genetic diversity in genetic depauperate populations of the same region. Our genetic analyses indicated that some French populations of G. palustris are of hybrid origin. These hybridization events are likely to be ancient as these populations are very isolated and some parent taxa went regionally extinct. As these hybrid populations may elucidate post-glacial distribution patterns of related Gladiolus taxa, we advocate that they deserve the same conservation efforts as purebred ones.

Highlights

Many endangered plant species are considered to suffer from the effects of ongoing habitat destruction, which has often led to an increased isolation and fragmentation of their populations
We studied the genetic population structure of the endangered G. palustris in the western part of its distribution area in France and Switzerland using AFLP markers to assess the effects of habitat fragmentation
The overall genetic diversity found in the populations of G. palustris was comparable to that of other Gladiolus species like G. hybridus (Chaudhary et al 2018) and other longlived perennial plant species (Nybom 2004)

Summary

Introduction

Many endangered plant species are considered to suffer from the effects of ongoing habitat destruction, which has often led to an increased isolation and fragmentation of their populations. In Europe, nutrient-poor wet grasslands belong to the most threatened and fragmented habitat types (van Duren et al 1997; Bakker and Berendse 1999; Oelmann et al 2009). Many of these grasslands have been drained and fertilized to increase agricultural productivity or have been abandoned. These changes in land use practices have led to the decline and genetic impoverishment of many plant species (Bakker and Berendse 1999; Vergeer et al 2003; Wesche et al 2012).

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Conclusion