The climatic and geological changes that occurred during the Quaternary, particularly the fluctuations during the glacial and interglacial periods of the Pleistocene, shaped the population demography and geographic distribution of many species. These processes have been studied in several groups of organisms in the northern hemisphere, but their influence on the evolution of Neotropical montane species and ecosystems remains unclear. This study contributes to the understanding of the effect of climatic fluctuations during the late Pleistocene on the evolution of Andean mountain forests. Firstly, by describing the nuclear and plastidic DNA patterns of genetic diversity, structure, historical demography and landscape connectivity of Quercus humboldtii, which is a typical species in northern Andean montane forests. Then, by comparing these patterns with the palynological and evolutionary hypotheses postulated for montane forests of the Colombian Andes under climatic fluctuation scenarios during the Quaternary. Our results indicated that populations of Q. humboldtii have high genetic diversity, a lack of genetic structure, and a historical increase in connectivity from the Last Glacial Maximum (LGM) to the present. Furthermore, our results showed a dramatic reduction in the effective population size followed by an expansion before the LGM, which coincides with the results found by palynological studies, suggesting a change in dominance in Andean forests that may be related to ecological factors rather than climate change.

Methodology for generation of the data files can be found on Zorrilla-Azcué et al., 2021

SSR_and_ENM_data_Qhumboldtii.xlsx - Contains 3 sheets:

            nSSR -  Contains genotypes for 10 chloroplast microsatellite (nSSR) loci for each Quercus humboldtii sample. Individual and population codes are also given (Sample ID and Pop ID). First row contains column headers and microsatellite code names (full names can be found in Zorrilla-Azcué et al., 2021).

            cpSSR - Contains data for 9 chloroplast microsatellite (cpSSR) loci for each Quercus humboldtii sample. Individual and population codes are also given (Sample ID and Pop ID). First row contains column headers and microsatellite code names (full names can be found in Zorrilla-Azcué et al., 2021).

         ENM_occurrence_records - Contains final occurrence points used to construct ecological niche models for Quercus humboldtii. This dataset is derived from the downloaded data in GBIF on 03 July 2019 https://doi.org/10.15468/dl.cnhmvu