Conservation Genetics of Four Critically Endangered Greek Endemic Plants: A Preliminary Assessment

Konstantinos Kougioumoutzis,Efthalia Stathi,Panayiota Kotsakiozi,Panayiotis Trigas,Aristeidis Parmakelis

doi:10.3390/d13040152

Abstract

The Mediterranean basin constitutes one of the largest global biodiversity hotspots, hosting more than 11,000 endemic plants, and it is recognised as an area with a high proportion of threatened taxa. Nevertheless, only a tiny fraction of the threatened Mediterranean endemics have their genetic diversity assessed, and we are unaware if and how climate change might impact their conservation status. This is even more pronounced in Eastern Mediterranean countries with a rich endemic flora, such as Greece, which hosts a large portion of the plant taxa assessed at the European level under the IUCN criteria. Using inter simple sequence repeats (ISSR) markers and species distribution models, we analysed the genetic diversity and investigated the impacts of climate change on four critically endangered and extremely narrow and rare Greek island endemic plants, namely Aethionema retsina, Allium iatrouinum, Convolvulus argyrothamnos, and Saponaria jagelii. All four species are facing intense anthropogenic threats and display moderate genetic diversity (uHe: 0.254–0.322), while climate change is expected to have a profound impact on their range size during the coming decades. A combination of in- and ex-situ measures, such as population reinforcement and seed bank conservation, are urgently needed in order to preserve these highly threatened and rare Greek endemics.

Highlights

The Mediterranean basin with its ca. 10,000 islands and islets is the second largest global biodiversity hotspot in the world [1,2,3,4] due to geographically structured diversification rates, spatio-ecological isolation [5], and high topographical and environmental heterogeneity [6]
We modelled the realized climatic niche of Aethionema retsina and Allium iatrouinum in an ensemble modelling scheme under the ensemble of small models (ESM) framework [80,81,82], which is suitable for modelling rare species [80,81,82], using the random forest (RF) modelling algorithm, which is robust to overfitting [83]
Since the trends for the future potential distribution of Aethionema retsina and Allium iatrouinum were identical across all sources of uncertainty, we present only the area range change for the WorldClim database and the

Summary

Introduction

The Mediterranean basin with its ca. 10,000 islands and islets is the second largest global biodiversity hotspot in the world [1,2,3,4] due to geographically structured diversification rates, spatio-ecological isolation [5], and high topographical and environmental heterogeneity [6]. The three Mediterranean peninsulas (the Iberian, the Italian, and the Balkan) have in general shaped the observed biogeographical patterns in the region [9,10] due to elaborate interactions between environmental and topographical factors [10,11,12,13,14,15] as well as due to the existence of several climatic refugia that allowed the persistence and the diversification of numerous plant lineages [16,17,18,19] This elevated species richness seems to be in peril though, since the Mediterranean basin is a global biodiversity hotspot of threatened taxa [20] and is considered as a high climate-change velocity area [21]. It is imperative to focus the conservation actions towards narrow endemic taxa, as their populations are usually highly fragmented and genetically depleted due to low size ([32] and references therein), meaning that their preservation is central in biological conservation [33]

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Conclusion