Large-scale phylogeographical patterns and the underlying factors driving species divergence in Mesoamerica are poorly understood, but it is widely documented that tectonic events and Pleistocene climate changes play an important role in determining species diversification. As glaciations in Mesoamerica developed only around high mountains, one hypothesis is that the known effects of the Last Glacial Maximum on the geographical distribution and genetic diversity of bird populations, producing the contraction/ expansion latitudinal pattern observed in temperate bird species, should be largely undetected in resident bird populations inhabiting environmentally more stable habitats. To gain insight into the effects of Quaternary habitat and climate stability on the genetic diversity, we use ecological niche modelling and generalised linear modelling to determine the role of changes in habitat stability on the genetic diversity in eight widespread or range restricted hummingbird species. We found lesser changes in suitable habitat from past to present in most of the species than those predicted by palaeodistribution models at northern temperate regions. Contemporary seasonal precipitation, Quaternary habitat and climate stability had superior explanatory power, but the magnitude and directionality of their effects on genetic diversity varied between range-restricted and widely distributed species. We observed that the species studied have not responded equally to changes in climate stability in this complex region, suggesting that habitat differences and/or the altitudinal range of the hummingbird species influenced genetic diversity, and that the species-specific responses are not only linked to habitat stability in the region but also to contemporary seasonality associated with the availability of floral resources.
With the end of MIS3, the unity of larger Gravettian settlements based predominantly on mammoth exploitation split into a mosaic of smaller Epigravettian sites with specific behaviors and economies. Based on C14 chronology, the site of Stránská skála IV (together with Grubgraben, Ságvár and Kašov), correlates with a brief warm period after the Last Glacial Maximum around 22 ka calBP. We detected two main accumulations of predominantly horse bones under a rock cliff suggesting that the site was not a regular settlement but rather a specialised hunting site. No features or hearths were recovered. Lithic raw materials were imported from long distances, and the horse hunting strategy profitted from the specific geographic qualitites of the site. Preferential location of Epigravettian sites in secluded valleys is a pattern generally recognized in Moravia and usually explained as a response to the harsh MIS2 climates. and Po skončení relativně příznivější periody MIS3 se původní jednota velkých gravettských sídlišť, převážně závislých na exploataci mamutů, proměňuje v mozaiku menších stanovišť epigravettienu (MIS2), které dokládají specifické chování a loveckou ekonomiku případ od případu. V letech 1985–1987 jsme pod skalním srázem na severním úbočí Stránské skály prozkoumali dvě centrální nálezové kumulace o průměru 5–7 m, tvořené převážně koňskými kostmi, prostoupené vápencovou sutí a nečetnou štípanou industrií epigravettienu (obr. 1–3; předběžně Svoboda 1990; 1991). Nálezy byly uloženy v nejvyšší části pleistocenní spraše, místy postižené následnou pedogenezí (obr. 4). Nebyly odkryty žádné sídelní struktury, tedy objekty ani ohniště, což ukazuje na specializované loviště využívající příhodný terén. Na základě radiokarbonové chronologie periody MIS2 a posledního glaciálního maxima (LGM) koreluje lokalita Stránská skála IV (spolu s lokalitami Grubraben, Ságvár a Kašov) s chladným obdobím GS-2.1c kolem data 22 ka calBP (Clark et al. 2009; Rasmussen et al. 2014; Hughes et al. 2016), ale podle paleobotanických analýz (viz níže) nebyly lokální klimatické podmínky tak drastické, jak bychom v této době očekávali.