The distribution and survival of trees during the last glacial maximum (LGM) has been of interest to paleoecologists, biogeographers, and geneticists. Ecological niche models that associate species occurrence and abundance with climatic variables are widely used to gain ecological and evolutionary insights and to predict species distributions over space and time. The present study deals with the glacial history of walnut to address questions related to past distributions through genetic analysis and ecological modeling of the present, LGM and Last Interglacial (LIG) periods. A maximum entropy method was used to project the current walnut distribution model on to the LGM (21–18 kyr BP) and LIG (130–116 kyr BP) climatic conditions. Model tuning identified the walnut data set filtered at 10 km spatial resolution as the best for modeling the current distribution and to hindcast past (LGM and LIG) distributions of walnut. The current distribution model predicted southern Caucasus, parts of West and Central Asia extending into South Asia encompassing northern Afghanistan, Pakistan, northwestern Himalayan region, and southwestern Tibet, as the favorable climatic niche matching the modern distribution of walnut. The hindcast of distributions suggested the occurrence of walnut during LGM was somewhat limited to southern latitudes from southern Caucasus, Central and South Asian regions extending into southwestern Tibet, northeastern India, Himalayan region of Sikkim and Bhutan, and southeastern China. Both CCSM and MIROC projections overlapped, except that MIROC projected a significant presence of walnut in the Balkan Peninsula during the LGM. In contrast, genetic analysis of the current walnut distribution suggested a much narrower area in northern Pakistan and the surrounding areas of Afghanistan, northwestern India, and southern Tajikistan as a plausible hotspot of diversity where walnut may have survived glaciations. Overall, the findings suggest that walnut perhaps survived the last glaciations in several refugia across a wide geographic area between 30° and 45° North latitude. However, humans probably played a significant role in the recent history and modern distribution of walnut.

Analysis of genetic structure and differentiation using 12 microsatellite loci of six walnut populations, three each from the Greater Caucasus and the Talysh, revealed a moderate range of variation. The observed number of alleles ranged from 2 to 11 alleles with a mean of 5.6 alleles per locus. The populations differed significantly for the frequency and composition of alleles for ten out of twelve loci assayed, and the mean number of alleles per locus ranged from 4.0 to 4.6 with approximately 92% of the loci polymorphic. The mean observed and expected heterozygosity for different populations indicated that the populations conformed to Panmixia. The mean F ST value indicates a significant departure from Hardy-Weinberg equilibrium, suggesting that there was significant differentiation among populations. The cluster analysis based on population pair-wise Nei's unbiased genetic distances and the distance Wagner tree indicated that the Talysh populations are significantly different from and placed as a sister group to the Caucasus populations.

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The results of this investigation show that Azerbaijan industries and agricultural sector provide considerable anthropogenic impact on the environment of Caucasus. The use of moss biomonitoring technique and neutron activation analysis (NAA) is a first attempt to study heavy metal atmospheric deposition in Azerbaijan, a country different relief and climate. The study was undertaken in the summer of 2015 of atmospheric deposition of man-made heavy metal pollutants in the area of mining and processing plant in Gadabay and Dashkasan mininig district. At the same time samples were collected from the Goygol State Reserve in the Lesser Caucasus not far from the city of Ganja. A total 85 moss samples (predominantly Pleurozium schreberi) collected in both environmentally contrast area. Elemental determination was carried out by epithermal neutron activation analysis (ENAA) at the reactor IBR-2 of Joint Institute for Nuclear Research (FLNP JINR). For the first time 44 elemental concentrations were determined (Na, Mg, Al, Si, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Mo, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb, Hf, Ta, W, Au, Th, U). Multivariate statistical analysis of the analytical results obtained will make it possible to identify the main sources of pollution and to assess the role of long-range transport of pollutants.