This study investigates changes in channel morphology of the Cetina River over the last 130 years affected by climate changes and various human impacts. A detailed digitalisation and analysis of the ...channel features was performed by using historical maps from the 1880s, archival aerial images from the 1950/60s, and contemporary orthophoto maps from the 2010s. According to these sources, we defined three study periods, and distinguished changes in the pre-dam phase (1880s–1950/60s) and the post-dam phase (1950/60s–2010s). In the pre-dam phase, a partial channel narrowing and drying of marsh zones in the source area were recorded, possibly due to reduced humidity and discharge following the end of the Little Ice Age. A drop in discharge and an increase in sediment supply caused by agricultural intensification most probably affected the expansion of fluvial bars. The increase in sediment supply is particularly evident in considerable river delta progradation of 500 m during this period. In the last 50 years, five hydroelectric power plants were built in the catchment. Consequently, severe reductions in discharge led to channel narrowing by about 50% which occurred in the third of the river length. Apart from the dam construction, a reduction in the area of bars by 85% and an increase in the number of islands by 103% can be related to decreased sediment supply following land abandonment and natural reforestation. This study adds to the knowledge on river morphology and channel adjustments following natural and strong human disturbances in the Mediterranean environment.
Coastal areas are dynamic and complex systems exposed to waves, high tides, and storm surges. Often, these areas are densely populated and have essential socio-economic values for the region and ...country. Any changes or disruptions can cause a tremendous social burden. Coastal Vulnerability Index (CVI) is one of the most used and straightforward methods to assess coastal vulnerability. This paper aims to analyse and summarise the current state of published coastal vulnerability indices. The analysis seeks to develop a regional vulnerability index for the eastern Adriatic coast, specifically for the Istrian peninsula. A total of 18 published papers were reviewed. A detailed survey was performed on three groups of variables that represent (a) the physical features of the coast, (b) the amount of influence of wave energy on the coast, and (c) exposed socio-economic factors. While choosing Physical and ecological variables is relatively straightforward, choosing Socio-economic variables is particularly challenging. The number of variables differs significantly from one author to another. As a result of the huge variety of global coastal characteristics and different research approaches, there is no universal CVI. Therefore, analysed indices are not suited for the calculation of the vulnerability of the Istrian coast without modification. A 5 × 5 m cell dimension was proposed as the most suitable for analysing the physical vulnerability of the Croatian coast of Istria.
This study investigates the quality and accuracy of remote sensing data in beach surveys based on three different data sources covering a 10-year period (2011–2021). Orthophotos from State Geodetic ...Administration Geoportal and satellite imagery from Google Earth were compared with orthophotos generated from UAV using ArcGIS Pro and Drone2Map. The beach area and length of 20 beaches on the island of Hvar were measured using each data source from different years. The average deviation for beach area (−2.3 to 5.6%) and length (−1 to 2.7%) was determined (without outliers). This study confirms that linear feature measurement is more accurate than polygon-based measurement. Hence, smaller beach areas were associated with higher errors. Furthermore, it was observed that morphological complexity of the beach may also affect the measurement accuracy. This work showed that different remote sensing sources could be used for relatively accurate beach surveys, as there is no statistically significant difference between the calculated errors. However, special care should always be addressed to the definition of errors.
U radu je analiziran geomorfološki sustav koji čine jaruga i žalo Zogon na otoku Hvaru s ciljem diferenciranja prirodnih i antropogenih procesa koji utječu na promjene žala. Primjenom metoda ...ponovljene fotografije, orto-foto snimaka i terenskog kartiranja ustanovljeno je da se u razdoblju od 60-ih godina 20. stoljeća do danas površina žala Zogon smanjila za oko 50 %. Smanjenje žala može se povezati s recentnim antropogenim djelatnostima na širem području istraživanja, osobito višestrukim nasipavanjem korita jaruge prilikom gradnje te manjim promjenama u korištenju zemljišta i prirodnom regeneracijom vegetacije što uzrokuje smanjenje dohrane žala. S druge strane, preokret u evoluciji žala u promatranom razdoblju, koje je po definiciji akumulacijski reljefni oblik, iz akumulacijskog ili stanja ravnoteže u stanje dominantne erozije možemo povezati s recentnim klimatskim promjenama i izdizanjem relativne morske razine.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The active tidal notches in the Makarska area, which were observed and described in historical records from the beginning of the 20th century (Andrijašević, 1910), have been reanalysed 107 years ...later. Detailed mapping of three locations in the wider Makarska area revealed their level of submergence, which varied between 30 and 37 ± 5 cm below the recent mean sea-level (MSL) according to location. This investigation points to the recent acceleration of relative sea-level change during the Current Warm Period (CWP) and also to the past temporary still-stand. According to data from Central Adriatic islands of Vis, Ravnik, and Biševo, this still-stand probably lasted around 500 years – during the Little Ice Age (LIA) period. However, the notch in the Dubrovnik area, which was, as stated in historical data (Suess, 1885–1908), active at the end of the 19th century, is still active today, indicating tectonic uplift of the Dubrovnik area.
The influence of tectonic forces on karst relief development has been studied using dolines as geomorphological markers. The strain and stress orientations have been calculated from the doline ...distribution, applying the centre to centre method (Ramsay, 1967; Fry, 1979). 623 local results have been obtained which were later injected into a 2D finite element model created in Castem 2 000 software. As the observed deformations arethe consequence of the tectonic displacements, the numerical model tends to simulate the tectonic conditions, which are closely related to the observed deformations. The results were correlated with the GPS measurements as well as with the geological field mapping results and great coincidence was observed.
Tufa is a fresh-water surface calcium carbonate deposit precipitated at or near ambient temperature, and commonly contains the remains of macro- and microphytes. Many Holocene tufas are found along ...the Zrmanja River, Dalmatian karst, Croatia. In this work we present radiocarbon dating results of older tufa that was found for the first time at the Zrmanja River near the Village of Sanaderi. Tufa outcrops were observed at different levels, between the river bed and up to 26 m above its present level. Radiocarbon dating of the carbonate fraction revealed ages from modern, at the river bed, up to 40 kBP ~20 m above its present level. These ages fit well with the hypothesis that the Zrmanja River had a previous surface connection with the Krka River, and changed its flow direction toward the Novigrad Sea approximately 40 kBP (Marine Isotope Stage 3). Radiocarbon AMS dating of tufa organic residue yielded a maximum conventional age of 17 kBP for the highest outcrop position indicating probable penetration of younger organic material to hollow tufa structures, as confirmed by radiocarbon analyses of humin extracted from the samples. Stable carbon isotope composition (δ13C) of the carbonate fraction of (−10.4 ± 0.6)‰ and (−9.7 ± 0.8)‰ for the Holocene and the older samples, respectively, indicate the autochthonous origin of the carbonate. The δ13C values of (−30.5 ± 0.3)‰ and (−29.6 ± 0.6)‰ for organic residue, having ages <500 BP and >5000 BP, respectively, suggest a unique carbon source for photosynthesis, mainly atmospheric CO2, with an indication of the Suess effect in δ13C during last centuries. The oxygen isotopic composition (δ18O) agrees well with deposition of tufa samples in two stages, the Holocene (−8.02 ± 0.72‰) and “old” (mainly MIS 3 and the beginning of MIS 2) (−6.89 ± 0.34‰), suggesting a ~4 °C lower temperature in MIS 3 compared to the current one.
This study presents high resolution oxygen and carbon isotopic record of two U-Th dated stalagmites from the Eastern Adriatic caves. The stalagmites were collected from Mala špilja and Velika špilja ...caves situated on Mljet Island in the southern part of the Croatian Adriatic. Dripwater samples were collected from Medvjeða špilja, Strašna peć, Špilja u Vrdolje, Kraljicina spilja, Velika špilja and Mala špilja caves. All caves formed in well-stratified Cretaceous limestones. The average value of deuterium excess of the dripwater is 9.3 %o, indicating that the atmospheric conditions over the Atlantic Ocean have greater influence on the isotopic composition precipitation in the Adriatic region than the Eastern Mediterranean Sea. The longest isotopic record of the speleothems is of stalagmite MSM-1 from Mala špilja Cave dated from 119.2 ±3.3 ka to 5.6±0.6 ka, although deposition was not continuous. During the Holocene the speleothem grew between 7 ka and 4 ka. That interval is characterized by several δ18Oc and δ13Oc fluctuations reflecting changes in the environment. Superimposed on these fluctuations, there is an increasing trend in the 7.0-6.5 ka interval, evident in elevated δ18sup O values, which primarily refers the trend to drier conditions in the eastern Adriatic, which were occasionally interrupted by wet intervals. Humid conditions are particularly pronounced by low δ13Oc and δ13Oc values of speleothem MSM-1 between 7.3 and 6 ka, as a reflection of increased precipitation and lower temperatures. The transition to today's Mediterranean climate (Cs) occurred between 6 ka and 5 ka, while the driest conditions are recorded at ~4.7 - 4.2 ka. Comparisons between the eastern Adriatic δ18Oc and δ13Oc records of the speleothem from Mala špilja Cave (MSM-1) and Velika špilja Cave (Mljet Island) with Soreq Cave (Israel) and Corchia Cave (Italy) together with other proxies such as lake sediments demonstrate that the speleothems from the Eastern Adriatic caves record the local and the regional climatic changes.
The first approach to the relationships between societies and physical environments on Velebit Mountain shows narrow correlations between spatial distribution of dolines, soil formation, hydric ...resources, vegetation and land occupation. In 2002, sediment cores have been obtained from different dolines of Velebit Mountain to evaluate the potential of their sedimentary archives in order to reconstruct the landscape history. On the littoral slopes and on the top parts of the mountain, the dolines were difficult to dig due to the presence of rocks in depth. Nevertheless, the cores have been sampled and soil analyses have been made (physical and chemical analyses: colour, grain size, pH, CaCO3, C, N, P, K, Mg, CEC). No dating materials were found. The first results attest to rather homogeneous pedologic processes in each area studied (Kamenica, Stinica, Baške Oštarije and Bilensko Mirevo), but they also indicate colluvial contributions. These contributions differ from one doline to another according to their location and morphology. Dolines reveal themselves to be not very good traps, as the representative nature of their sedimentary archives could be very local. However, the best profile has been obtained at Bilensko Mirevo, which shows a change in the soil nutrient content from an impoverishment in its middle part toward an increase of the soil nutrients in recent parts. Those environmental changes could not be precisely dated, but could be correlated with the 17th to 20th century phase of strong human impact on the Velebit environment and with the rural depopulation observed since the second half of the 20th century.Keywords: karst, dolines, Mediterranean soils, Velebit Mountain,Dinarides, Croatia.
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