Perhaps there were northern refugia in LGM? The phylogeographic structure of the thermophilic tree Carpinus betulus in the Carpathian region.

Carpinus betulus L., the hornbeam, is a component of lowland and highland forests in Europe. By examining the postglacial migratory history of thermophilic tree species, the study aimed to unravel their putative glacial microrefugia in the Carpathian region. The present study points to the two distinct genetic AFLP groups of C. betulus in the Carpathian region that represent different genetic lineages based on Bayesian analysis. They differed in Nei's gene diversity index h, and the analysis of molecular variance AMOVA showed a percentage variation of the populations between the groups of 13.74 %. Principal coordinate analysis (PCoA) of 368 AFLP tree samples confirmed the presence of two genetic groups. Ninety-five populations underwent principal component analysis (PCA) to show the main correlations between genetic diversity indices and bioclimatic/climate variables (WorldClim and Carpatclim). The generalized logistic model (GLM) showed the significance of Nei's genetic index h in delimiting genetic groups. The results of population-genetic and multivariate analyses determined that the two genetic groups nowadays are spatially diffused and do not show a clear geographic pattern, pointing to a genetic melting pot. We found ecological links between genetic diversity and bioclimatic characteristics, especially the precipitation in the coldest quarter - Bio19. The refugial Maxent model indicates a significant contribution of the Bio7 variable (both linked with a continental type of climate) to the occurrence of the species during the LGM in Europe. We suggest the relict character of hornbeam populations in a specific climatic-terrain niche in the northern part of the Carpathian Basin.

Subalpine woody vegetation in the Eastern Carpathians after release from agropastoral pressure.

The subalpine vegetation in the Eastern Carpathians has been under agropastoral influence as a high-mountain open pasture for about five centuries. Today, the subalpine zone released by human intervention is growing as thickets. In this study, we use a numerical model of tree crowns (CHM, Canopy Height Model) based on laser scanning (LiDAR) and a high-resolution digital terrain model (DTM) to delineate the subalpine thicket distribution. Anselin 'Local Moran's I' statistic was used to find hot and cold spots in vegetation cover. We used a logistic generalized linear model (GLM) and Principal Component Analysis (PCA) to set for the historical, climatic and terrain conditions candidates as the predictors of the present-day distribution of vegetation hot spots. We use variance partitioning to assess the interaction of climate and terrain variables. The resulting model suggests key environmental controls that underlie the vegetation pattern. Namely, snow in terrain depressions protects woody vegetation against abrasion and winter drought and increased insolation reduces the site humidity in the summer on S-E exposure hampering re-vegetation. In addition, the increasing distance from the treeline declines the rate of secondary succession. In all, the spatial model predicts the 35% coverage by thickets as a theoretical maximum of available climatic-terrain niches. The results suggest that the growth of the subalpine thicket, in the face of growing global temperature, may be restricted due to the limited number of niches available.

Intra-annual groundwater levels and water temperature patterns in raised bogs affected by human impact in mountain areas in Poland.

Over the last century, the vast majority of peatlands in Europe have experienced substantial transformation as a result of drainage works that led to an imbalance in the natural hydrologic regime as well as changes in vegetation composition. The ongoing study aims to reconstruct the natural hydrologic regime of peatlands and restore their typical vegetation communities. In this study, we examine the variability of groundwater levels and groundwater temperature in raised bogs located in the Bieszczady Mts. in southern Poland. Both groundwater table levels and groundwater temperature serve to characterise the hydrology of peatlands, which in turn is critical for plant growth and rates of relevant biochemical processes. Our objective is to determine the predominant scale of intra-annual variability in time series and identify their potential sources by assessing the adaptive response of peat bogs to key changes in weather conditions. For this purpose, data obtained from 9 monitoring wells located in peat bogs, with a varying degree of degradation, were used. Fluctuations in time series and potential linkages between selected variables were analysed in the frequency domain using the continuous wavelet transform. The results show that peat bogs exhibit a relatively high stability of groundwater table levels and groundwater temperature despite meaningful changes in weather conditions. The most visible response of peat bogs to weather conditions was observed in summer and autumn. Our study demonstrates that degraded peat bogs experience the largest decrease in groundwater table levels and more frequent fluctuations. In contrast, groundwater temperature remained stable throughout the year at all the studied bog sites.