Feurdean A.,Biodiversity and Climate Research Center |
Marinova E.,Catholic University of Leuven |
Nielsen A.B.,Lund University |
Liakka J.,Biodiversity and Climate Research Center |
And 8 more authors.
Journal of Biogeography | Year: 2015
Aim: The forest steppe of the Transylvanian Plain is a landscape of exceptionally diverse steppe-like and semi-natural grasslands. Is this vegetation a remnant of a once continuous temperate forest extensively cleared by humans, or has the area, since the last glacial, always been a forest steppe? Understanding the processes that drive temperate grassland formation is important because effective management of this biome is critical to the conservation of the European cultural landscape. Location: Lake Stiucii, north-western Romania, central-eastern Europe. Methods: We analysed multi-proxy variables (pollen, coprophilous fungi, plant macroremains, macrocharcoal) from a 55,000 year discontinuous sequence (c. 55,000-35,000; 13,000-0 cal. yr bp), integrating models of pollen-based vegetation cover, biome reconstruction, global atmospheric simulations and archaeological records. Results: Needleleaf woodland occurred during glacial Marine Isotope Stage (MIS) 3, but contracted at the end of this period. Forest coverage of c. 55% (early Holocene) and 65% (mid-Holocene) prevailed through the Holocene, but Bronze Age humans extensively cleared forests after 3700 cal. yr bp. Forest coverage was most widespread between 8600 and 3700 cal. yr bp, whereas grasses, steppe and xerothermic forbs were most extensive between 11,700 and 8600 cal. yr bp and during the last 3700 cal. yr bp. Cerealia pollen indicate the presence of arable agriculture by c. 7000 cal. yr bp. Main conclusions: We have provided the first unequivocal evidence for needleleaf woodland during glacial MIS 3 in this region. Extensive forests prevailed prior to 3700 cal. yr bp, challenging the hypothesis that the Transylvanian lowlands were never wooded following the last glaciation. However, these forests were never fully closed either, reflecting dry growing season conditions, recurrent fires and anthropogenic impacts, which have favoured grassland persistence throughout the Holocene. The longevity of natural and semi-natural grasslands in the region may explain their current exceptional biodiversity. This longer-term perspective implies that future climatic warming and associated fire will maintain these grasslands. © 2015 John Wiley & Sons Ltd.
Cheburu C.N.,Romanian Academy
Revista medico-chirurgicalǎ̌ a Societǎ̌ţaii de Medici ş̧i Naturaliş̧ti din Iaş̧i | Year: 2011
Chitosan is a linear, natural cationic polysaccharide comprising beta-1,4 linked glucosamine and N-acetyl-D-glucosamine. Hydrogels of chitosan were prepared by crosslinking with varying amounts of glutaraldehyde. It can be used as a bacteriostatic, fungistatic and coating agent, and the gels and suspensions may play the role of carriers for slow release or controlled delivery of drugs, as an immobilizing medium and an encapsulation material. MATERIAL AND METHODS: Chitosan and glutaraldehyde were used to prepare the hydrogels and their characteristics were investigated by Fourier transform infrared (FT-IR) spectroscopy and the inhibitory effect on cellular growth was tested by chemiluminescence assay. The hemolytic activity was also determined by direct contact with human blood and the concentration of hemoglobin was spectrophotometrically measured. RESULTS AND DISCUSSION: Chitosan hydrogels have no inhibitory effect on cell growth, and hemolytic action below 1%, which means good blood compatibility; therefore they are promising materials.
Cogalniceanu D.,Ovidius University |
Cogalniceanu G.-C.,Romanian Academy
Biodiversity and Conservation | Year: 2010
Biodiversity is declining worldwide under increasing human pressure. Since the location of and the threats are unevenly distributed and the resources available for conservation are limited, prioritization is essential to reduce the losses. Most conservation efforts until now proved to be ineffective in stopping the present worldwide decline of threatened species. We focus on the European Union (EU) after the repeated enlargements in the last decade, from 15 to 27 countries, by considering the present conservation priorities that have shifted towards a continental scale approach. The situation in the EU indicates that despite the differences in wealth across countries, there are no significant differences in the number and surface of protected areas between them, so re-evaluating conservation priorities at a continental scale and a reallocation of funds is required. A major limitation in priority settings for conservation is data availability. We recommend including in the decision process data provided by phylogeographic studies. This will prevent the decline of populations and species with evolutionary potential from centres of speciation and climate refugia. Recent EU members from central and eastern Europe still retain high biodiversity with a rather good conservation status. A large number of areas with high evolutionary potential identified by phylogeographic studies are located there and should be considered priorities within the context of global changes, as a proactive approach. We recommend a periodic re-evaluation of the status of species and habitats based on current research results, harmonization between the priority species listed in the conventions, directives and Red Lists at both EU and national levels. © Springer Science+Business Media B.V. 2010.
Dragota C.-S.,Romanian Academy |
Kucsicsa G.,Romanian Academy
Carpathian Journal of Earth and Environmental Sciences | Year: 2011
A series of aspects in the evolution and characteristic features of some environmental variables are clearly related to global climate change, some climatic variables being major indicators of this change-induced disturbances. In the Rodnei Mountains National Park, at the Weather Station Iezer, some manifestations of global warming are visible in the evolution of air temperature and of the quantity of precipitation, particularly in the warm season of the year. As significant is the effect of the variation in the major climate indicators connected directly with the thermal and/or precipitation regime. Some of the main indicators analyzed in this paper suggest that multi-annual mean temperatures and shower days are increasing, while the annual precipitation mean and snow pack thickness are decreasing, foggy days and liquid precipitation become more numerous, solid precipitation days being ever fewer. All these aspects are relevant of the extent to which the study-area is being affected by global climate change.
PubMed | Romanian Academy
Type: Journal Article | Journal: Revista medico-chirurgicala a Societatii de Medici si Naturalisti din Iasi | Year: 2011
Chitosan is a linear, natural cationic polysaccharide comprising beta-1,4 linked glucosamine and N-acetyl-D-glucosamine. Hydrogels of chitosan were prepared by crosslinking with varying amounts of glutaraldehyde. It can be used as a bacteriostatic, fungistatic and coating agent, and the gels and suspensions may play the role of carriers for slow release or controlled delivery of drugs, as an immobilizing medium and an encapsulation material.Chitosan and glutaraldehyde were used to prepare the hydrogels and their characteristics were investigated by Fourier transform infrared (FT-IR) spectroscopy and the inhibitory effect on cellular growth was tested by chemiluminescence assay. The hemolytic activity was also determined by direct contact with human blood and the concentration of hemoglobin was spectrophotometrically measured.Chitosan hydrogels have no inhibitory effect on cell growth, and hemolytic action below 1%, which means good blood compatibility; therefore they are promising materials.