Restricted dispersal in the late successional species Nothofagus pumilio: May it endure under global change?

Abstract

The goals of this study are to identify the genetic and phenotypic basis of local adaptation, and to determine the spatial scale at which demographic history, natural selection, gene flow, and major environmental drivers affect genetic diversity and local adaptation in N. pumilio. In addition, this study wants to test whether local adaptation along major environmental gradients evolved convergently among the southern beech and seven tree species from Europe including beech and oak. For these purposes, we will link genetic variation in a set of ~1,000 candidate genes with dendrophenotypes to quantify the genomic response of individuals and populations to environmental differences along two clines. The first cline is the latitudinal gradient along the Andean main ridge that will allow investigating pathways influenced by cues of the light regime e.g. circadian clock related genes. The second cline is an east-west gradient that at the same time is an elevational and consequently temperature as well as precipitation gradient that will allow investigating pathways linked to these climatic parameters. In addition, we will investigate the response of trees to stress events unlinked to these gradients, namely ENSO related climatic variability and pest outbreaks (Paritsis et al. 2009). In a next step, our results will be compared to currently ongoing studies with identical experimental design conducted in seven European tree species that among others include the relatively closely related Fagus sylvatica and Quercus robur as well as the very distantly related conifer Picea abies. Besides the better understanding of the genetic foundation of local adaptation in essential pathways, identifying the scale of genetic diversity and local adaptation will help inform foresters to implement more targeted management strategies of forest genetic resources. For example, our results can be translated into the identification of provenance zones for N. pumilio (see above).