Ecological niche modeling meets phylogeography to unravel hidden past history of key forest genera in plant geography: Podocarpus and Nothofagus

Abstract

Phylogeographical methods and ecological niche modeling of cold-tolerant taxa, Podocarpus parlatorei a montane tropical conifer and Nothofagus pumilio inhabiting temperate areas of the southern Andes, were used as case studies to test if present populations are the result of local survival during cooling. Samples collected along their ranges were analyzed by nuclear isozymes and uniparentally inherited chloroplast DNA sequences. Modern and past last glacial maximum (LGM) ecological niche modeling (ENM) was developed using current climate data based on 19 bioclimatic variables and topography. Populations of the subtropical of P. parlatorei shared most haplotypes, southern populations were genetically distinct, and ENM yielded range expansion during the LGM. Latitudinally extreme populations of the temperate N. pumilio shared isozyme variants which was consistent with ENM showing suitable northern and southern areas. In contrast cpDNA yielded an ancient phylogeographic structure. Cold-hardy trees locally persisted along their ranges through ice periods without major range shifts in tropical and temperate regions.