CGL2010-18381 - Persistiendo en el límite: estructura ge

The range dynamics of species in response to modern climate change are likely to be determined largely by population responses at range margins. In contrast to the expanding edge, the low-latitude limit of species ranges remains understudied, and the critical importance of its populations as long-term stores of species’ genetic diversity and evolutionary history during the Quaternary has been little acknowledged. Here we propose to study a set of 19 low-latitude marginal populations of Quercus robur (Pedunculate oak), one of the most important European forest trees, in order to elucidate how these have been able to sustain their viability and genetic diversity through multiple glacial cycles, and which are their perspectives under modern climate change.

For this purpose, we investigate how genetic diversity is distributed and transmitted across populations. Because gene dispersal plays a central role in this process, we examine patterns of historical and contemporary gene flow at three levels: within populations, among populations, and between species (i.e., hybridising with the closely related and much more abundant Quercus pyrenaica). Finally, germination and growth experiments under controlled conditions will be used to assess whether 1) low levels of genetic variation associated to small population size actually result in reduced fitness and decreased drought tolerance and 2) hybridisation with the more stress-tolerant Q. pyrenaica results in better performances of Q. robur under marginal conditions.

The ultimate objective of this study is to better understand how glacial relict populations persist under adverse conditions and to provide valuable background information for the development of appropriate strategies for their conservation and management in a changing, and presumably drier, climate