Marginal areas in alpine ecosystems: definition and evolutionary value in a context of climate change

Abstract

In the context of climate change, populations are increasingly being subjected to the extreme selective pressures that define environmental marginality. The determination of the evolutionary value and adaptive potential of marginal populations is still a challenge of great relevance and has direct implications on biodiversity conservation. To face this challenge, it is advisable to take into account the main factors that affect evolutionary adaptation (genetic diversity, selective pressures and gene flow). In this work, we present a roadmap that starts with the definition of the concept of environmental marginality and integrates field experiments with lab work, including the use of environmental niche models, genetic and genomic studies, in situ and ex situ common garden experiments, gene flow simulations and reciprocal sowings, to determine the evolutionary potential of populations that occur in environmentally marginal areas, and, thus, their conservation value. For this purpose, we used as a study case the research carried out on Silene ciliata populations in the Central System. Our studies show that some populations that occur in marginal areas keep significant high levels of genetic diversity and present clear evidences of local adaptation. Therefore, these results outline the relevant conservation value that marginal populations may have, especially in a context of climate change.