Adaptive genetic potential of European silver fir in Romania in the context of climate change

Five provenance tests with twenty-six European silver fir autochthonous populations were used in order to assess the response of populations to climate change. Height growth and diameter at breast height of trees at age 31 years were considered as response variables and eight climate variables as predictors. Climatic variables for the trial sites and for origin location of provenances were calculated from 1961 to 2010. The experiments revealed a large genetic variability within species level and a plastic response to climate change, which certainly has a genetic basis. The transfer to warmer climate has resulted in an increase of the provenances growth, in the trial sites situated on the lower vegetation layer. But growth is significantly influenced by mean annual temperature and annual precipitation of planting site and also by the differences in mean annual temperature, annual precipitation, monthly mean temperature in July and July precipitation between provenance site and test site. These are the climatic factors which should be associated with risk in case of the transfer of forest reproductive materials. The provenance origin should be especially considered if the species will be planted outside of its current climate optimum. The best provenances in terms of total height and diameter at 1.30 m came from origin climate close to site climate, small transfer distances. Based on growth response functions and RCP4.5 scenario, we could project the shifts in species distribution for 2050s and 2100s and identify vulnerable populations.</p

Variability and Change in Water Cycle at the Catchment Level

This study proposes a simple methodology for assessing future-projected evolution of water cycle components (precipitation, potential evapotranspiration, and potential runoff) based on the two-level Palmer model of the soil and their impact on drought conditions at basin level. The Palmer Drought Severity Index (PDSI) is used as drought metric. The catchments of rivers Arges, Mures, Prut, Siret and Somes (mid- and lower Danube basin) have been chosen as case studies. The present climate data consist of Romanian gridded dataset, monthly precipitation and values of streamflow from Romania and Republic of Moldova and potential evapotranspiration-related data from the Climate Research Unit (University of East Anglia). We used as future projections five numerical experiments with regional models obtained through the EURO-CORDEX initiative, under two Representative Concentration Pathway scenarios. The correlations between observed streamflow at the river basin outlets and PDSI-related components of the water cycle show that PDSI represents reasonably well processes taking place in the selected catchments. Depending on the specific scenario and catchment, droughts that in the Palmer classification were deemed as incipient, mild or severe under present climate will become a normal summer feature toward the end of this century, especially over catchments situated in the lower Danube basin

Changes in snow cover climatology and its elevation dependency over Romania (1961–2020)

Study Region: Romanian territory and the Carpathian Mountains, Romania.Study focus: We provide a consistent picture of long-term changes in relevant snow cover characteristics, including phenology (timing of the snow onset and melting), snow cover duration, and frequency of snow cover and snow-free days in Romania, from 1961 to 2020, that could be relevant for understanding the regional dynamics of terrestrial water resources.New hydrological insights: The trend behaviour shows different dynamics between the elevation bands and Koeppen-Geiger climate regions of Romania, which may play a crucial role in the variability of snow water budgets and the distribution of water resources. We found systematic delays in snow onsets and earlier snow melting throughout the country. These trends are particularly prominent at mid-elevations and in the lowlands, reflecting the contribution of the intensified seasonal warming process in the last decades. We also observed widespread and significant declines in snow cover duration, snow cover day frequency, and increases in snow-free days in most climate regions of the country. The trends in snow cover parameters are elevation-dependent up to 2000 m. Above 2000 m the observed changes are visibly diminished or reversed (e.g., earlier snow onsets in the alpine areas). The long-term snow cover variability shows significant shifts in the mean of the snow cover parameters, generally clustered during the 1990 s or earlier. Relationships between the large-scale atmospheric circulation (herein expressed as NAO) and changes in seasonal temperature and precipitation have been identified

Defining a Precipitation Stable Isotope Framework in the Wider Carpathian Region

The eastern part of Europe is very poorly represented in the Global Network for Isotopes in Precipitation (GNIP) database, mainly because the monitoring of the stable isotopes in precipitation started only recently compared with other regions. In this respect, the main objective of this article is to fill the gap in the GNIP database over the eastern part of Europe and show the temporal variability and potential drivers of an extended network of δ18O values in precipitation collected from 27 locations in Romania and the Republic of Moldova. We also present the first high-resolution map of the spatio-temporal distribution of δ18O values in precipitation in Romania and the Republic of Moldova, according to an observational dataset. According to our results, the stations from western and northern Romania tend to have LMWLS with higher values than those from southwestern Romania. The monthly variation of the δ18O and δ2H showed a clearly interannual variation, with distinct seasonal differences, following the seasonal temperatures. The analysis of the spatial distribution of stable isotopes in precipitation water was made on the basis of both observational data and modeled data. This allowed us to study the origin of the air moisture and the interaction with regional and local patterns and to analyze the link between the spatial δ18O variations and the large-scale circulation patterns on a seasonal scale