Reintroduction of a dioecious aquatic macrophyte (Stratiotes aloides L.) regionally extinct in the wild. Interesting answers from genetics

Abstract

ABSTRACT1. The reintroduction of a plant species regionally extinct in the wild poses a stimulating conservation challenge. If the species is dioecious and the ex situ preserved population is only of one sex, the challenge is even more difficult. To assess whether the female population of Stratiotes aloides originally studied requires a reinforcement to increase its genetic variation, and to determine from which source male individuals should be taken to re-establish a viable population, the genetic structure of nine different accessions of S. aloides across Europe and Asia were analysed -six native populations and the last three Italian populations, preserved ex situ.2. Amplified fragment length polymorphism (AFLP) fingerprinting of 190 individuals from these populations was performed using six primer combinations and chromosome counts.3. AFLP markers revealed medium to high values of genetic diversity at the population level, unexpectedly including residual ex situ accessions. Neighbour-joining tree, PCoA and STRUCTURE analyses indicate the presence of three genetic patterns identifiable in the central-western, central and eastern Europe-Asian populations. Chromosome counts revealed the presence of diploid (2n = 24) and tetraploid (2n = 48) populations.4. Similarity between populations belonging to different hydrographical basins, and differences between neighbouring populations could be explained through long-distance bird-mediated dispersal events. Genetic analysis showed that reinforcement with female individuals from other European populations to increase the genetic diversity of the Italian female population is not necessary. Surprisingly, the geographically closest male population (Bavaria) to the Po basin is not the best option for male reintroduction. Instead, male individuals should be reintroduced from the Rhine basin (Netherlands) and eastern part of the Danube basin (Romania).

Persistence of submerged macrophytes in a drying world: Unravelling the timing and the environmental drivers to produce drought‐resistant propagules

“…Dioecious species, however, possess male and female shoots. This characteristic may complicate the re‐establishment of viable self‐sustaining populations (Orsenigo et al, ).…”

“…Dioecious species, however, possess male and female shoots. This characteristic may complicate the re-establishment of viable self-sustaining populations (Orsenigo et al, 2017). During their development, the colour of oogonia changes from light green/light orange to dark green/brown.…”

Editorial: How to halt the extinction of wetland‐dependent plant species? The role of translocations and restoration ecology

“…It is generally accepted that genetic variation within populations in aquatic plants tends to be low, but strong differentiation among populations seems to be common, mainly owing to the persistence of long-lived clones (Bruni et al, 2013;Chen, Xu, & Huang, 2007). Exceptions to this statement are not uncommon, however (Orsenigo et al, 2017;Russell et al, 1999;Santamaria, 2002). Low levels of genetic differentiation found among populations of wetland-dependent plant species are attributed to dispersal strategy (Santamaria, 2002).…”

“…(last collected in New Zealand in the 1940s; de Lange, ), Nymphaea thermarum Eb.Fisch. (only known in the wild from the type locality in south‐west Rwanda, collected in 1987, and now considered Extinct in the Wild; Juffe, ), Stratiotes aloides L. (regionally extinct in Italy; Orsenigo et al, ), or Trapa natans L. (regionally extinct in Spain; Moreno, ). Others are close to extinction, such as the annual dwarf Veronica oetaea Gustavsson or the aquatic quillwort Isoetes malinverniana Ces.…”

“…The disappearance of aquatic plants may trigger a shift from a clear macrophytedominated state to a turbid phytoplankton-dominated state (Scheffer, Hosper, Meijer, Moss, & Jeppesen, 1993), with drastic effects on trophic systems, a decline in invertebrate and vertebrate species, and a reduction in ecosystem service functions. Some wetland species are already globally or regionally extinct, such as Stellaria elatinoides (regionally extinct in Italy; Orsenigo et al, 2017), or Trapa natans L.…”