Marcel Mîndrescu

High mountain region of the Northern Romanian Carpathians responded sensitively to Holocene climate and land use changes: A multi-proxy analysis

A high-altitude lake sediment sequence (Buhăiescu Mare, 1918 m a.s.l.) in the subalpine zone of the Rodna Mountains was analysed through a multi-proxy approach to determine the sensitivity of high mountain habitats to climate, fire and land use changes. The early Holocene regional forests were dominated by Pinus (sylvestris and mugo) and replaced by Picea abies from 9800 cal. yr BP. After an extended hiatus in the profile (c. 9800–4200 cal. yr BP), probably because of the physical removal of sediments through avalanche or high-flow events, P. abies, Abies alba and Fagus sylvatica forests developed after 4200 cal. yr BP. The timberline and treeline reacted sensitively to past changes in climate and human impact. The site was probably situated above the treeline throughout most of the investigated period. However, a treeline ecotone or krummholz zone may have sporadically reached the lake’s elevation in the early Holocene. A decline in timberline and treeline elevation was noted during the last 1200 years, and more evidently over the past 200 years, with replacement by subalpine shrubs (Alnus viridis) and alpine herbaceous communities. Because these vegetation changes were associated with an increased prevalence of pollen-based anthropogenic indicators, charcoal particles and abiotic indicators, human-induced fires and clearance and resultant erosion inputs to the lake are implied. Effects of current warming on the altitude range of trees are not yet visible, probably because land use has more strongly contributed to changes in land cover than the climate fluctuations of the last millennium in the Rodna Mountains.

Lakes, Lacustrine Sediments, and Palaeoenvironmental Reconstructions

Acting as sensitive and accurate barometers, lake and peat sediment records enable us to acquire an increasingly broader perspective on the mechanisms behind climatic and environmental changes. Over the past two decades, the rising number and amount of data yielded by palaeolimnological studies for the Central–Eastern Europe, in general, and Romania, in particular, allowed for the construction of a wide network of well-dated records which enabled comparison with the hallmark palaeoclimatic event stratigraphy of the North–Atlantic area and Western Europe. More specifically, the combined use of biological indicators with physical and geochemical data resulted in a multi-proxy approach for a variety of sites extending from the Transylvanian lowlands to the uplands of the Romanian Carpathians and spanning throughout the Holocene to the Pleniglacial. This section introduces a brief synthesis of the most outstanding results delivered by various investigations on Romanian lake and peat archives. Among these, lakes and peat bogs which came into existence during deglaciation, including both glacial lakes located in higher elevation mountain areas and lakes formed at lower elevations due to landslides subsequent to permafrost thaw are prevalent, and were preferred for such studies due to their long lifespan and location in mountain areas which have exhibited increased sensitivity to centennial and millennial-scale climate changes. The potential of lacustrine sediments for inferring past dynamics of climate and environmental conditions prompts us to highlight the necessity for expanding the spatiotemporal coverage of such studies in Romania in an attempt to create a relatively unitary perspective on regional palaeoenvironmental evolution.

550 years in sedimentological record from a varved type lake (Bolătău, Bukovina, NE Romania) - changing storm frequency and climate fluctuation

In the present paper we introduce lake Bolătău, located in Obcina Feredeului, Eastern Carpathians (Romania), with seasonally controlled sedimentation and significant potential for generating precipitation sensitive proxy record. Two sediment cores were compared against each other in order to achieve a better understanding of the lateral discontinuity of observed microfacies and an accurate interpretation of the sedimentological data.

Interdisciplinary cooperation and studies in geoscience in the Carpathian Basin

An interdisciplinary approach to geoscience is particularly important in this vast research field, as the more innovative studies are increasingly crossing discipline boundaries and thus benefitting from multiple research methods and viewpoints. Grasping this concept has led us to encourage interdisciplinary cooperation by supporting and promoting the creation of “meeting places” able to provide a framework for researchers and scholars involved in geoscience research to find common grounds for discussion and collaboration. Most recently, this was achieved by organizing the 1st Workshop on “Interdisciplinarity in Geosciences in the Carpathian Basin” (IGCB) held in the Department of Geography at the University of Suceava (Romania), between the 18 th and 22 nd October 2012. This event brought together both an international group of scientists and local researchers which created opportunities for collaboration in research topics such as geography, environment, geology and botany, biology and ecology in the Carpathian Basin.

Glacial Cirques in the Romanian Carpathians and Their Climatic Implications

This section summarizes a morphometric analysis of glacial cirques from the Romanian Carpathians, further inferring climatic information from spatial patterns of morphometric traits. Results derived from the detailed statistical analysis of a comprehensive database of glacial cirques are presented briefly. The distribution of cirques by altitude, aspect, size, classification (cirque grade), and geology is presented and related to controlling factors. New contributions concerning the palaeoglaciation level during Late Pleistocene in the Romanian Carpathians, and the direction of prevailing winds during glaciation are provided. Statistical distributions of cirque size and shape are outlined and illustrated. A comprehensive data base of all glacial cirques in the Romanian Carpathians is now available to guide or substantiate further comparative or/and interdisciplinary studies. It is also possible to rank the mountain ranges by the degree of glacial modification.

Sensitivity of the hypsometric integral (HI) and its connections with lithology and neotectonics in the Rodna Mountains, Romanian Carpathians

This study investigates the sensitivity of the hypsometric integral (HI) and its connections with lithology and neotectonics from northern Romanian Carpathians, Rodna Mountains. Two types of DEM was used in analysis (a 30m DEM resolution with specific grid size and a non-gridded 30m DEM resolution). Several methods have been applied in order to calculate HI as: the CalHypso GIS extension was used to automatically extract multiple hypsometric curves from digital elevation model (DEM) and to calculate the main statistics related to the HI by applying polynomial fits; local indices of spatial autocorrelation were applied using Anselin Local Moran’s I and Getis-Ord Gi* in order to see if HI distribution has spatial patterns values and selection of valid squares (500m 2 grid using 30m DEM using ArcMap 10.1) for the lithological analysis. The values of the hypsometric kurtosis density, kurtosis, skew and density skew are increasing eastwards. Values of hypsometric skewness for the northern slope are in range between 0.290 – 0.816 and sowthern part between 0.414 – 0.507. The results show that HI values are higher than 0.5 in the areas with recent tectonic influences especially in northern part near Dragos Vodă fault system. The formations with a Oligocene, Miocene, Pleistocene and Holocene age have low values ( 0.5). Comparing HI values from these two analysis (500m grid size DEM and the DEM without grid size) of the DEM we find some slightly differences in HI values specially in the northern part of the range on Repedea, Negoiescu Mare, Fântâna and Lala basins

Electrical resistivity tomography (ERT) surveys on glacial deposits in Romanian Carpathians

The study presents preliminary results regarding the use of electrical resistivity surveys in the assessment of the internal structure of the glacial deposits from the Romanian Carpathians. ERT is a geophysical method used to quantify changes in electrical resistivity of the ground towards passing electric current across an array of electrodes and simultaneous measurement of the induced potential gradient. Using specific software the measurements are further processed and correlated with the topography in order to obtain bedrock resistivity features. Therefore, the method is useful to evaluate the characteristics of geological strata and is widely used for mapping shallow subsurface geological structures. In the mountain regions ERT studies have been applied in different glacial and periglacial geomorphological studies - for permafrost detection (in Romanian Carpathians - Urdea et. al., 2008; Vespremeanu-Stroe et al., 2012), slope deformation analysis, the assessment of slip surface depths, sediment thickness, groundwater levels etc. One of the most commonly 2-D array used is the Wenner electrode configuration, which is moderately sensitive to both horizontal and vertical ground structures. Due to their elevations and Pleistocene’s climatic conditions, the Romanian Carpathians have been partially affected by Quaternary glaciations. The glaciers descended to about 1050-1200 m a.s.l. (Urdea and Reurther, 2009) in the Transylvanian Alps and Rodna Mountains (Eastern Carpathians) carving a large number of U-shaped valleys and glacial cirques (Mindrescu, 2006) and forming accumulations of unconsolidated glacial debris (moraines). Our study areas are two sites located in the northern (Rodna Mts.) and southern (Iezer Păpusa Mts.) part of the mountain range.

Alpine treeline and timberline dynamics during the Holocene in the Northern Romanian Carpathians

High altitude environments (treeline and alpine communities) are particularly sensitive to climate changes, disturbances and land-use changes due to their limited tolerance and adaptability range, habitat fragmentation and habitat restriction. The current and future climate warming is anticipated to shift the tree- and timberlines upwards thus affecting alpine plant communities and causing land-cover change and fragmentation of alpine habitats. An upslope movement of some trees, shrubs and cold adapted alpine herbs as a response to the current climate warming has already been noted in many montane and subalpine regions. Four Holocene peat and lacustrine sediment sequences located between 1670 and 1918 m a.s.l. (Fig.1), in the Rodna Mountains (Northern Romania, Eastern Carpathians) are used with the aim to determine: i) the sensitivity of high mountain habitats to climate, fire and land use changes; ii) tree- and timberline shifts: and iii) the influence of landscape topography on trees and shrubs.

Dendrochronological assessment and radiocarbon dating of subfossil coniferous macroremains excavated from a peat bog, Maramures Mts, Romania

Fifty-six subfossil samples have been collected from a peat bog located on the Vinderel plateau, Farcău massif, Maramureș Mountains (Romania). The majority of wood-remains are Norway spruce (Picea abies) and Silver fir (Abies alba). The samples have been subjected to dendrochronological analysis and 7 samples were selected for AMS radiocarbon analysis. Seven floating chronologies have been developed from these subfossil samples, so far. The longest floating chronology contains 166 years and the shortest spans 47 years. Radiocarbon age obtained for the oldest and youngest samples are 1717 ± 19 yr 14C BP (255 – 388 cal AD) and 1039 ± 16 yr 14C BP (985 – 1023 cal AD), respectively.

1000 years of high resolution environmental change in the Eastern Carpathians, NE Romania: a multi-proxy approach

Climate changes and anthropogenic activities are projected to have a significant impact on mountain environments. This is because of their ecosystems’ sensitivity and increased response to the extreme weather events and natural catastrophes (Beniston, 2000). The modification of climatic conditions can therefore impact heavily on mountain ecosystems. Furthermore, human impact has been shown to modify environmental response to climatic stressors (Beniston, 2003; Jones & Mann, 2004). This holds particularly true because mountain regions are usually at the border of conflicting interests between economic development and environmental conservation (IPCC, 1996). Deciphering the relation between local mountain environment, climate variability and human components therefore becomes of great importance for both regional climate study and local socio-economies.