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Visokogorsko područje dinarskog krša obilježeno je raznolikošću reljefnih formi, koje su u kombinaciji s humidnom klimom i različitim odnosima dolomita i vapnenaca, posebice u pogledu brzine i načina trošenja, dodatni izvor varijabilnosti fiziografije tla. U Nacionalnom parku Risnjak dimenzijama se ističu dvije ponikve (Viljska ponikva - VIP i Velika ponikva - VP) gdje smo testirali hipotezu o postojanju značajnih razlika u fiziografiji površinskog dijela tla. Cilj je bio istražiti u kojoj se mjeri uzduž osojne i prisojne padine ponikve mijenjaju kemijske značajke površinskog dijela tla i očituje li se pri tomu i razlika između dviju ponikvi, s obzirom na postojanje razlike u njihovoj litološkoj građi i poziciji unutar gorskog masiva. Istraživanja su provedena tako da je u svakoj ponikvi postavljen transekt u pravcu ~sjever-jug preko dna ponikve, na komu je obavljeno uzorkovanje tla do dubine od 15 cm (ili do stijene, ako je tlo pliće). Pokazalo se da je u VIP izraženija diferencijacija prirode humusa u organičnom horizontu i da ona dobro korespondira s diferencijacijom vegetacije. U VP se fizička trošivost stijena (dolomitični supstrat) odražava na fiziografiji tla u obliku karbonatnosti i više pH-vrijednosti, koja u VIP raste od dna prema rubu ponikve, dok se u VP pH-vrijednost značajno ne mijenja uzduž padina. Na osojnoj ekspoziciji u VIP je udio organskog ugljika u tlu značajno veći (377 g kg–1) od udjela na prisojnoj ekspoziciji (97 g kg–1), pri čemu na osojnoj ekspoziciji udio organskog ugljika opada od dna prema rubu ponikve, a na prisojnoj ekspoziciji se očituje blagi rast. Za razliku od navedonoga, u VP udjel organskog ugljika ima obrnuti trend. Slične odnose i trendove pokazuje i udjel ukupnog dušika, osim pri dnu osojne padine u VIP, gdje je Ntot relativno nizak, a Corg relativno visok.Zaključno, fiziografija tla dubokih gorskih ponikvi krša pod snažnim je utjecajem prirode stijena u pogledu dolomitičnosti. Tlo povrh dolomita i dolomitičnih vapnenaca obilježeno je karbonatnošću. U ponikvama u masivima čvrstih vapnenaca može se očekivati na njihovim osojnim padinama karakteristične trendove pH-vrijednosti tla te udjela organskog ugljika i ukupnog dušika zbog vrlo izraženog hidrotermičkog, odnosno bioklimatskog trenda. Na prisojnim ekspozicijama takvih ponikvi analogni trendovi s karakterističnim gradijentima izostaju, što korespondira i s izostankom prepoznatljivog vegetacijskog slijeda., The high mountain area of ​​the Dinaric karst is characterized by a variety of relief forms, which in combination with humid climate and different relationships of dolomite and limestone, especially in terms of rate and nature of weathering, are an additional source of variability of soil physiography. In the Risnjak National Park, two sinkholes stand out in terms of dimensions (Viljska ponikva - VIP and Velika ponikva - VP), where we tested the hypothesis of the existence of significant differences in the physiography of the surface part of the soil. The aim was to investigate the extent to which the chemical characteristics of the surface part of the soil change along the shady and sunny slopes of the sinkhole and whether the difference between the two sinkholes is evident, given the difference in their lithological structure (VIP is sinkhole in limestone and VP is sinkhole in dolomitic limestones and calcite dolomites) and positions within the mountain massif. The research was carried out in such a way that in each sinkhole a transect was placed in the direction north-south over the bottom of the sinkhole, on which soil sampling was performed to a depth of 15 cm (or to the rock, if the soil is shallower). Sampling was performed on rows of profiles in 5 replicates, which were placed perpendicular to the transect with a height difference of 10 m (Fig. 1). In each sinkhole, 22 rows of profiles were set up, on which 110 soil samples were collected, and the pH value, carbonate content, organic carbon content and total nitrogen content were measured on them. The research showed that on the shady slope in VIP, in addition to vertical vegetation differentiation, there is also a differentiation of the nature of humus in the organic horizon (hemimor, modermor, sphagnomor). This differentiation is much less pronounced in the VP, and on the sunny slope in both sinkholes it is almost absent. In VP, the physical weathering of rocks (dolomitic substrate) is reflected in the physiography of the soil in the form of free carbonate and higher pH values ​​(Figs. 9 and 10). In VIP the pH rises from the bottom towards the edge of the sinkhole, both on the shady and sunny slope, while in VP the pH value does not change significantly, both along the shady and along the sunny slope. A recognizable factor in the spatial variability of carbonate content and pH value of this soil is phytopedoturbation in the form of tree felling and ejection of carbonate particles on the surface of the sinkhole slope, where they are exposed to gravitational and water erosion and further redistribution down the slope.At the shady slope in VIP, the share of organic carbon in the soil is significantly higher (377 g kg – 1) than the share at sunny slope (97 g kg – 1). At the shady slope the share of organic carbon decreases from the bottom to the edge of the sinkhole (Fig. 11), and a slight increase is evident on the sunny slope. In VP, the mean values ​​on the slopes and the trends of these shares on the slopes in relation to VIP have the opposite relationship (Fig. 12). Similar relatios and trends are shown by the share of total nitrogen (Fig. 13), except at the bottom of the shady slope in VIP. Here, the share of Ntot is relatively low, and the share of Corg is relatively high, so only in this part within both transects does C/N differ significantly from the remaining parts of the transects (Fig. 14).In conclusion, the soil physiography of deep karst sinkholes is strongly influenced by the nature of the rocks in terms of dolomiticity. The soil above the dolomite and dolomitic limestones is marked by carbonates. In deep sinkholes in solid limestone massifs, characteristic trends of soil pH and the content of organic carbon and total nitrogen can be expected on their shady slopes due to a very pronounced hydrothermal and bioclimatic trend. Analogous trends with characteristic gradients are absent on the sunny slopes of such sinkholes, which corresponds to the absence of a recognizable vegetation sequence.

Estimation of forest floor loading is important for many forest management applications, especially those related to fire management and carbon balance. We quantified the physical properties (depth, fuel load, bulk density) and carbon stocks of endemic Dalmatian black pine (Pinus nigra J.F. Arnold subsp. dalmatica [Vis.] Franco) forest floor layers. We also examined how these properties differ with stand age and layer. Forest floor depths ranged from 1.5 cm to 11.5 cm and forest floor fuel (FFF) loads ranged from 11.9 Mg ha-1 in the young stand to 197.3 Mg ha-1 in the old stand. Forest floor carbon (FFC) stocks ranged from 6.4 Mg C ha-1 in the young stand to 85.8 Mg C ha-1 in the old stand. We developed regression equations that can be used to convert the investigated forest floor depth into load in each layer individually and across all layers. These equations, together with the organic carbon (OC) concentration determined here for individual forest floor layers, simplify quantification of carbon stocks in the forest floor. Bulk density (BD) values reported here can also be used to convert depth measurements to loads for each layer and the entire forest floor. The results presented here are suitable for rapid estimation of FFF loads and FFC stocks based solely on forest floor depth, without the need to sample and analyze large amounts of forest floor fuels. Similarly, spatial distribution in FFF loads and carbon stocks can be assessed simply by measuring forest floor depths.

Fuel moisture content (FMC) is the mass of water contained within vegetation in relation to the dry mass. It is one of the most important variables in all wildfire prediction and spread simulation models. FMC has great influence on wildfire ignition and combustion. For accurate wildfire spread simulations and wildfire risk index estimations, fuel moisture is a very important input variable. Since 2016, Croatian firefighters in everyday practice use Web based System for wildfire behaviour modelling and wildfire spread simulation named AdriaFirePropagator. The simulator is based on semi-empirical Rothermel’s surface fire spread model for wildfire behaviour modelling and cellular automata for wildfire spread simulation. Fuel moisture, both live and dead is a very sensitive parameter in wildfire behaviour modelling. Live fuel moisture defines the moisture content of live fuels and dead fuel moisture is defined as moisture of dead fuels with time-lag of 1 hour, 10 hour and 100 hours. In Croatia there is no organised service for daily measurement of fuel moisture content, so values of these variables has to be estimated from meteorological parameters. This paper compares three approaches to fine dead fuel estimation, all implemented in AdriaFirePropagator. The first one, used in most wildfire simulation software, was based on standard mathematical models that relate air temperature, air humidity, 24-hours rainfall and wind speed with fine dead fuel moisture (FFMC). The second one was based on standard Fire Behavior Analysis Tables (FBA Tables) and the third one was based on intensive experimental research of dead fine fuel moisture content of Aleppo pine (Pinus halepenses Mill.). After intensive experimental research new Croatian fine dead fuel models PhFFMC was developed, tested in selected pine species stand and applied in AdriaFirePropagator for fuel regions where this pine species dominate. Croatian model is much better correlated with experimental data, therefore for more accurate wildfire simulations, similar models have to be developed also for other typical vegetation fuel types.

During the last three decades, there has been an increase in the incidence of severe crown fires affecting black pine forests in the sub-Mediterranean area. The objective of this study was to develop and test a model to predict fine fuel moisture content for Dalmatian black pine (Pinus nigra J.F. Arnold subsp. dalmatica (Vis.) Franco) needle litter. We performed laboratory measurements of equilibrium moisture content and response time of dead black pine needles to modify the hourly fine fuel moisture code (FFMC) model, and we compared the predictive ability of the hourly FFMC model with that of modified model (PnFFMC). Field tests showed that although the hourly FFMC model reproduced trends in moisture content of black pine needles quite well, it consistently overestimated moisture content (mean absolute error 3.9%). The PnFFMC model performed better than the hourly FFMC model and was closer to the line of equivalence (mean absolute error 0.9%). This study indicates that the hourly FFMC can easily be modified by incorporating appropriate species-specific equilibrium moisture content and response time values, leading to more accurate predictions of fine fuel moisture content. The need to use recently fallen needles in fuel moisture modelling for Mediterranean pine species is highlighted.

Matični supstrat, uz klimu, reljef, organizme i vrijeme, predstavlja jedan od pet glavnih pedogenetskih čimbenika. S pedogeneskog stajališta najvažnija su svojstva matičnog supstrata: mineralni i kemijski sastav, način i intenzitet trošenja te sadržaj biogenih elemenata. Cilj ovog rada je utvrditi utjecaj različitih matičnih supstrata na fizičke i mineralne značajke tla. Na području PP Medvednice na šest različitih litoloških cjelina otvoreno je 80 pedoloških profila: metamorfne stijene – dominantno škriljevci, metamorfne stijene – dominantno filiti, magmatske stijene, pješčenjaci, lapori i lako trošivi vapnenci. Uzorci tla uzeti su po horizontima, a analizirani su oni iz humusnoakumulatinog (A-horizont) i B-horizonta. Određeni su sljedeći parametri: debljina horizonata, dubina profila, udjel skeleta, garnulometrijski sastav tla, postojanost strukturnih mikroagregata i mineralni sastav tla (XRD) metodom rendgenske difrakcije. Rezultati istraživanja pokazuju da postoje statistički značajne razlike između različitih litoloških cjelina za sve promatrane varijable osim debljine horizonata. Najveće dubine tla su povrh laporovitih stijena, a najmanje na dolomitiziranim vapnencima, što je ponajprije uvjetovano načinom trošenja matičnog supstrata. Na svim istraživanim litološkim cjelinama, tla na području PP Medvednice vrlo su postojanih mikroagregata. U odnosu na B-horizont u humusnoakumulativnom horizontu utvrđena je veća postojanost strukturnih mikroagregata. Tla povrh lakotrošivih vapnenaca imaju statistički veći udjel gline i manji udjel krupnog i sitnog pijeska od tla ostalih litoloških cjelina. Za sve litološke cjeline teksturna oznaka najčešće je u rasponu od praškaste do glinaste ilovače, dok je na litološkoj cjelini povrh vapnenaca udjel gline statistički značajno veći, pa je teksturna oznaka u rasponu od praškaste glinuše do glinuše. Litološke cjeline povrh magmatskih i metamorfnih stijena imaju statistički značajno manji udjel minerala kvarca i veći udjel minerala klorita i feldspata u odnosu na sedimentne stijene.

Sa stajališta šumskih požara, šumska prostirka se promatra kao potencijalno gorivo, no njena uloga i značaj u izmjeni tvari i energije, a poglavito ugljika u kontekstu aktualnih globalnih klimatskih promjena su veliki. Zbog toga se informacije o šumskoj prostirci tradicionalno koriste u modelima za procjenu opasnosti od šumskih požara te modelima za predikciju ponašanja i širenja šumskih požara, a u novije vrijeme i za procjenu emisija ugljika i drugih plinova te kvantificiranje zaliha ugljika. Glavni ciljevi ovog rada su: određivanje debljine, gustoće i količine pothorizonata šumske prostirke uz pripadajuće zalihe ugljika u sastojinama alepskog bora te izrada regresijskih modela debljine i količine šumske prostirke te debljine i zalihe ugljika, po pothorizontima i ukupno. Uzorkovanje šumske prostirke obavljeno je na području NP Mljet, u sastojinama alepskog bora, po debljinskim razredima: 0–50 cm, 100–150 cm i 200–250 cm opsega. Uzorkovanje je obavljeno po pothorizontima, a količine i udio organskog ugljika određene su za svaki pothorizont zasebno. Iz dobivenih rezultata vidljivo je da sastojine alepskog bora vežu značajne količine ugljika u svojoj prostirci, no uvjeti i zakonitosti nisu još dovoljno proučeni. U prilog tomu govore značajno veće debljine i količine šumske prostirke u sastojinama alepskog bora od onih do sada poznatih, pa je tako ispod stabala opsega 200–250 cm utvrđena srednja debljina prostirke od 9,0 cm i procijenjena količina od 94,3 Mg ha–1 sa zalihom ugljika od 37 Mg C ha–1. Regresijskom analizom utvrđena je statistički značajna veza debljina šumske prostirke s količinama prostirke i zalihama ugljika, te su dani regresijski modeli za OL pothorizont, zatim za OF1,OF2 i OH zajedno, kao i za ukupnu prostirku. Rezultati ovog istraživanja imaju praktičnu vrijednost u jednostavnijem kvantificiranju količina goriva i zaliha ugljika u šumskoj prostirci sastojina alepskog bora, koje se potom mogu koristiti u navedenim modelima. Inventarizacija šumskih goriva predstavlja osnovu za parametrizaciju i operativnu primjenu navedenih modela u Hrvatskoj.

Background and Purpose: This paper deals with the results of the investigation of the selected heavy metal contents in forest soil in the region of an abandoned mine. The analysis of the forest ecosystem soil on the Medvednica Mountain was conducted in the region of the so-called “French Mines” (FM). The elements selected for analyses were cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) because of their toxicological characteristics. Material and Methods: In the investigated area - five entrances of the FM - composite topsoil samples (0–5 cm) were taken. Those samples were compared to the control samples which were taken outside the area affected by mines. The soil samples were analysed for the following parameters: pH, particle size distribution, organic C content and pseudo-total mass fractions of the selected heavy metals. The heavy metals were determined by atomic emission spectrometry with inductively coupled plasma (ICP-MS). Results and Conclusion: The results reveal that the soil is locally polluted, i.e. the highest mass fraction values of these four heavy metals were found in the area of the FM. Average pseudo-total fraction of Cd in the analysed topsoil samples was in the range of 0.17–4.41 mg·kg−1 (median: 0.97 mg·kg−1). Cu was found in the range of 4.54–1260 mg·kg−1 (median: 45.7 mg·kg−1). In the case of Zn, mass fraction values were found in the range of 36.8–865 mg·kg−1 (median: 137 mg·kg−1). Finally, average values of the pseudo-total fraction of Pb were found in the range of 58.4–12000 mg·kg−1 (median: 238 mg·kg−1). The results reveal that mining activities leave consequences on soil for a long time.

A quantitative analysis of pedo-physiological indicators aimed at determining changes in the soil attributable to the effects of spruce plantations was done. The study was conducted at eight sites in central and north-western Croatia where spruce plantations were planted in the late 20th century. At each site, a pedological profile was opened within the spruce plantation and the endo-morphological parameters of the soil were determined. Composite soil samples from two depths (0-10 cm and 10-20 cm) and from the forest floor were taken in the spruce plantation and compared with samples taken at plots covered by natural vegetation (natural stands) located in the surroundings. The following pedo-physiographic indicators were measured on the collected soil samples: quantity of forest floor, particle size distribution of soil, pH values in H2O and in CaCl2 aqueous solution (concentration 0.01 mol dm-3), content of Corg, content of Ntot and content of bioavailable nutrients (using the Mehlich III method). The results showed that the forest floor had a higher mass in the spruce plantations than in natural stands. The mineral soil showed clear trends of influence of the spruce plantations on soil in terms of reduced pH values. Most plots in the spruce plantations showed a lower nitrogen content in the soil, a higher C/N ratio and lower content of bioavailable phosphorus. This study provides an insight into the amelioration effects of spruce plantations on soil, and represent a reliable basis for decision-making in planning specific interventions in terrestrial ecosystems, such as the establishment of new forest plantations.

This paper presents the results of the preliminary testing of the selected trace elements in the soils of several parks in the city of Zagreb, Republic of Croatia. In each park, the samples were taken from several points-at various distances from the roads. The samples were taken at two different depths: 0-5 and 30-45 cm. Composite samples were done for each sampling point. Microwave-assisted wet digestion of the soil samples was performed and the determination by ICP-AES technique was done. Results obtained for Al, As, Ba, Mn, Ti, V, and K are in a good agreement with the results published in the scientific literature so far. The mass fraction values of Cd, Cr, Cu, Ni, Pb, and Zn are somewhat higher than the maximum values given in the Croatian Directive on agricultural land protection against pollution. Be, Mo, Sb, Se, and Tl in the samples were present in the concentrations that are lower than their method detection limit values.

Ice and snow caves are distributed throughout Croatia in the Dinaric karst mountain belt. Most of them are located on Velebit Mt., 1200 m a.s.l. in the zone with snow (boreal) climate. In the past, some of them were used for ice excavation for water and conservation purposes. First mentions occurred in the 17th century and the first researches in 19th century. During the second half of 20th century in some ice cave microclimates, geomorphological and glaciochemical researches started. According to data from deep shafts in Velebit Mt., there is the deepest recorded cave ice in the World. The depth of the ice recorded there is up to 550 m. In the frame of chemical researches, tritium and element concentration, stable isotope and age of the ice were studied.

Pinus halepensis (Mill.) is the most widely distributed and abundant Mediterranean pine, as well as one of the species most affected by wildfires in Europe. The objective of this study was to develop and test an operationally useful fine fuel moisture prediction model for P. halepensis needle litter below the fibre saturation point, where flammability increases rapidly with decreasing moisture content. The predictive ability of the hourly Fine Fuel Moisture Code (FFMC) was also evaluated. Even though the hourly FFMC model is designed for pine litter, it consistently over-predicted moisture content of P. halepensis needle litter and could not track the rapid moisture change during the day. Experimental measurements of equilibrium moisture content and response time of dead P. halepensis needles were used to modify the hourly FFMC model. The modified model performed better than the hourly FFMC model on all evaluation parameters, with a mean absolute error of 1% moisture content. Our results suggest that fine fuel moisture prediction models should be species-specific in order to achieve the accuracy needed for precise prediction of fire behaviour.

Matični supstrat, uz klimu, reljef, organizme i vrijeme, predstavlja jedan od pet glavnih pedogenetskih čimbenika. S pedogeneskog stajališta najvažnija su svojstva matičnog supstrata: mineralni i kemijski sastav, način i intenzitet trošenja te sadržaj biogenih elemenata. Cilj ovog rada je utvrditi utjecaj različitih matičnih supstrata na fizičke i mineralne značajke tla. Na području PP Medvednice na šest različitih litoloških cjelina otvoreno je 80 pedoloških profila: metamorfne stijene – dominantno škriljevci, metamorfne stijene – dominantno filiti, magmatske stijene, pješčenjaci, lapori i lako trošivi vapnenci. Uzorci tla uzeti su po horizontima, a analizirani su oni iz humusnoakumulatinog (A-horizont) i B-horizonta. Određeni su sljedeći parametri: debljina horizonata, dubina profila, udjel skeleta, garnulometrijski sastav tla, postojanost strukturnih mikroagregata i mineralni sastav tla (XRD) metodom rendgenske difrakcije. Rezultati istraživanja pokazuju da postoje statistički značajne razlike između različitih litoloških cjelina za sve promatrane varijable osim debljine horizonata. Najveće dubine tla su povrh laporovitih stijena, a najmanje na dolomitiziranim vapnencima, što je ponajprije uvjetovano načinom trošenja matičnog supstrata. Na svim istraživanim litološkim cjelinama, tla na području PP Medvednice vrlo su postojanih mikroagregata. U odnosu na B-horizont u humusnoakumulativnom horizontu utvrđena je veća postojanost strukturnih mikroagregata. Tla povrh lakotrošivih vapnenaca imaju statistički veći udjel gline i manji udjel krupnog i sitnog pijeska od tla ostalih litoloških cjelina. Za sve litološke cjeline teksturna oznaka najčešće je u rasponu od praškaste do glinaste ilovače, dok je na litološkoj cjelini povrh vapnenaca udjel gline statistički značajno veći, pa je teksturna oznaka u rasponu od praškaste glinuše do glinuše. Litološke cjeline povrh magmatskih i metamorfnih stijena imaju statistički značajno manji udjel minerala kvarca i veći udjel minerala klorita i feldspata u odnosu na sedimentne stijene., The highly complex lithological structure as well as topographic characteristics of the Medvednica area are responsible for its profound vegetational, micro-climatic and pedophysiographic diversity. In view of the quality of the original soil-forming material, the first place is taken by rocks and their detritus which directly govern soil physical composition. The best indicators of soil physical composition are its depth, colour, skeletal nature, particle size distribution, soil density, density of soil solid phase, total porosity, water capacity, air capacity, structure and hydraulic properties. On Medvednica, these vary greatly and play the main role in defining soil quality. The success of ecosystem management depends on the knowledge of the above factors. The goal of this research is to determine how the lithological base, or parent material, primarily affects physical (horizon thickness, profile depth, skelet proportion, soil texture, soil structure) and mineral soil properties.A total of 80 pedological profiles were opened in the Medvednica Nature Park area and evenly distributed so as to comprise all the representative lithological units. Samples of physically altered soils were taken from genetic horizons, as well as a fragment of rock, i.e. parent material, for the purpose of determining the lithological rock affiliation. Soil samples has been analayzed in the humus-accumulative (A horizon) and first under mineral horizon (mostly B horizon). The differences between the topsoil humus-accumulative and B horizon were statistically analyzed per lithological units. The samples were prepared (ISO 11464 2006) and analyzed in the laboratories of the Faculty of Forestry of the University of Zagreb and at the Croatian Geological Institute in Zagreb. According to FAO (2006), the following was determined in situ: the proportion of skelet per genetic horizon, horizon thicknesses and total profile depth. Laboratory analyses of the samples taken from genetic horizons included the particle size distribution according to ISO 11277:2009, stability of structural microaggregates according to Pernar et al. (2013) and mineral soil composition (XRD) using the X-ray diffraction method on X-ray diffractrometer X’Pert PRO MPD.For the needs of statistical analysis, parent material was divided into six characteristic units, leaning in part on the classification of Halamić et al. (2001) used during geochemical research of stream sediments on Medvednica. The lithological unit LIT1 is represented by metamorphic rocks, predominantly greenschists, muscovite chlorite and quartz-muscovite schists. The lithological unit LIT2 is represented by metamorphic rocks, predominantly phyllites. The lithological unit LIT3 consists of igneous rocks, predominantly diabases and spilites. The lithological unit LIT4 are Mesozoic clastic rocks of Lower Cretaceous age, and comprise sandstones, siltites and shales. The lithological unit LIT5 consists of Mesozoic and Tertiary clastic rocks dominantly represented by marls. LIT6 is made up of Tertiary carbonate rocks represented by lithotamnic limestones together with clay limestones (Figure 1).Statistical analysis was performed with Statistica 7 software. Descriptive statistics was made for all the analyzed variables, including the number of samples, arithmetic means and standard deviation. Differences between the analyzed variables by lithological units were tested with a one-way analysis of variance (ANOVA), on condition that the assumption of homogeneity of variance was satisfied. For those variables in which the test of homogeneity of variance was not satisfied, the Kruskal-Wallis non-parametric test was used. Type I error (a) of 5 % was considered statistically significant.The following soil types were identified in the opened pedological profiles: dystric cambisol, eutric cambisol, calcaric cambisol, stagnosol, regosol and luvisol (the percentage ratio by representation is 62 % – 19 % – 10 % – 4 % – 3 % – 2 %).Based on the comparison of soils formed in six different lithological units, it can be concluded that physical and mineral soil properties depending on type of litological units. Silty to clay loam is the most represented textural class in Medvednica Nature Park. It was found on metamorphic rocks above greenschist and phyllite, igneous rocks, sandstones and marls, whereas on easily weathered limestones the textural class ranges from silty clay to clay. The analysis of particle size distribution (content of individual fractions) showed that the profiles developed on silicate lithological parent material have on average higher sand content compared to the profiles developed on carbonate rocks, which is conditioned by the manner of parent rock weathering. Higher clay content above easily weathered limestones eventually led to variability of the textural class in relation to other lithological units. In all the investigated lithological units in terms of structural microaggregate stability, the soils in Medvednica Nature Park manifest highly stable microaggregates. In relation to the B-horizon, the humus-accumulative horizon revealed higher stability of structural microaggregates, which can be attributed to higher content of organic matter in the topsoil horizon. The soils above igneous and metamorphic rocks have significantly lower content of the mineral quartz and higher content of the minerals chlorite and feldspar in relation to the soil above sedimentary rocks. There was no difference in muscovite/illite contents in lithological substrates. Soil was the deepest above marl rocks and the shallowest above dolomitised limestones, which is primarily conditioned by the manner of parent material weathering.Our research highlights all the complexity and heterogeneity of the geological-lithological structure of Medvednica. In combination with other pedogenetic factors, it manifests even higher soil heterogeneity, which eventually causes problems in the processing and interpretation of the results.This research provides reference data on physical and mineral properties of soils in Medvednica Nature Park in the most represented lithological units. However, these data should be taken with caution and should be compared with the results of other similar studies, since the same lithological parent material may give rise to the formation of soils of different taxonomic affiliation, depending on the changes in the constellation of other pedogenetic factors (climate, vegetation, relief).

Sa stajališta šumskih požara, šumska prostirka se promatra kao potencijalno gorivo, no njena uloga i značaj u izmjeni tvari i energije, a poglavito ugljika u kontekstu aktualnih globalnih klimatskih promjena su veliki. Zbog toga se informacije o šumskoj prostirci tradicionalno koriste u modelima za procjenu opasnosti od šumskih požara te modelima za predikciju ponašanja i širenja šumskih požara, a u novije vrijeme i za procjenu emisija ugljika i drugih plinova te kvantificiranje zaliha ugljika. Glavni ciljevi ovog rada su: određivanje debljine, gustoće i količine pothorizonata šumske prostirke uz pripadajuće zalihe ugljika u sastojinama alepskog bora te izrada regresijskih modela debljine i količine šumske prostirke te debljine i zalihe ugljika, po pothorizontima i ukupno. Uzorkovanje šumske prostirke obavljeno je na području NP Mljet, u sastojinama alepskog bora, po debljinskim razredima: 0–50 cm, 100–150 cm i 200–250 cm opsega. Uzorkovanje je obavljeno po pothorizontima, a količine i udio organskog ugljika određene su za svaki pothorizont zasebno. Iz dobivenih rezultata vidljivo je da sastojine alepskog bora vežu značajne količine ugljika u svojoj prostirci, no uvjeti i zakonitosti nisu još dovoljno proučeni. U prilog tomu govore značajno veće debljine i količine šumske prostirke u sastojinama alepskog bora od onih do sada poznatih, pa je tako ispod stabala opsega 200–250 cm utvrđena srednja debljina prostirke od 9,0 cm i procijenjena količina od 94,3 Mg ha–1 sa zalihom ugljika od 37 Mg C ha–1. Regresijskom analizom utvrđena je statistički značajna veza debljina šumske prostirke s količinama prostirke i zalihama ugljika, te su dani regresijski modeli za OL pothorizont, zatim za OF1,OF2 i OH zajedno, kao i za ukupnu prostirku. Rezultati ovog istraživanja imaju praktičnu vrijednost u jednostavnijem kvantificiranju količina goriva i zaliha ugljika u šumskoj prostirci sastojina alepskog bora, koje se potom mogu koristiti u navedenim modelima. Inventarizacija šumskih goriva predstavlja osnovu za parametrizaciju i operativnu primjenu navedenih modela u Hrvatskoj., From the aspect of forest fires, the forest floor is considered a potential fuel: however, in the context of current global climate change it plays an exceptionally important role in the exchange of matter and energy and of carbon in particular. For this reason, forest floor data are traditionally used in forest fire danger rating and in fire behavior and spread models. More recently they have also been used to estimate emissions of carbon and other gasses and to gasses and to quantify carbon stocks. The main objectives of this study are to a) determine the depth, bulk density and fuel load for each forest floor horizon with the associated carbon stock in Aleppo pine stands and b) develop regression models that relate forest floor depth to forest floor fuel load and forest floor depth to forest floor carbon stock, for horizons and for the entire forest floor. Forest floor sampling was carried out in Aleppo pine stands situated in Mljet National Park, per 0-50 cm, 100-150 cm and 200-250 cm circumference classes. Each forest floor horizon was sampled separately, and fuel load and organic carbon content were determined for each horizon. Our results suggest that Aleppo pine stands contain significant carbon stocks in the forest floor, but relations and processes that influence these stocks have not been sufficiently studied. This is supported by significantly greater forest floor depths and fuel loads in Aleppo pine stands than previously reported. Thus, the mean depth of forest floor of 9.0 cm, fuel load of 94.3 Mg ha-1, and carbon stock of 37 Mg C ha–1 were determined under trees with a 200-250 cm circumference class. Regression analysis revealed a statistically significant relationship between depth and fuel load and between depth and carbon stock. Regression models were given for the OL horizon, the OF1,OF2 and OH horizons, as well as for the entire forest floor. Our results have practical value as they will allow reliable quantifications of forest floor fuel loads and carbon stocks in Aleppo pine stands by using easily measurable fuel characteristic, which can then be applied in the aforementioned models. The forest fuel inventory provides the basis for parameterization and operational use of a number of forest resource management applications in Croatia.

Like in other types of forests the greatest changes in the soil of floodplain forest stands occur during their regeneration. These changes are manifested as changes in the content and dynamics of organic matter in the soil. Research was conducted in oak and ash floodplain forests in the eastern part of Croatia and in southern Moravia in the Czech Republic. The results showed that the type and extent of these changes depended, in addition to environmental factors, also on the technology of forest regeneration. The natural regeneration of oak in floodplain forests of Spacva (eastern Croatia) protects soil from dramatic changes in soil by successive regeneration felling and that it retains the plant cover permanently. The weight of organic matter on the soil surface is increased after regeneration till the period when the effect of thinning becomes evident (about 70 years). In the surface mineral layer of soil the pH value increases after shelterwood felling. Stand regeneration with clear-cutting results in a rapid change in the conditions of surface humus accumulation and decomposition. The process of organic residue accumulation is interrupted in the clearings. In the preparation of soil/site by ploughing, the concentrations of nitrogen and carbon slightly decrease. The management impact depends on the method of site preparation for the establishment of a new stand. The selection of a method of the floodplain forest regeneration (particularly of oak) is markedly dependent on actual ecological conditions and on ecological and historical experience of the given region.

Odabrane zemnoalkalijske i alkalijske kovine Ca, Mg, K i Na sastavni su dio stijena litosfere i spadaju u 8 najzastupljenijih elemenata Zemljine kore. Trošenjem stijena na površini Zemljine kore u procesima pedogeneze postaju sastavnim djelom tla. S gledišta biljne ishrane, ovi se elementi ubrajaju u biljna hraniva i to K, Ca i Mg u makroelemente, odnosno potrebne (esencijalne) elemente, a Na u korisne (beneficijalne) elemente.Cilj ovog istraživanja je utvrditi kako litološka podloga, odnosno matični supstrat na području PP Medvednica utječe na udjel Ca, Mg, K i Na u tlu, te je li njihova prostorna raspodjela osim litološkom podlogom uvjetovana i reljefom.U šumi na području PP Medvednica uzet je 181 kompozitni uzorak po pravilnoj mreži 1 × 1 km u površinskom sloju tla do 5 cm dubine. Otvoreno je 28 pedoloških profila ravnomjerno raspoređenih, tako da obuhvate sve litološke cjeline. Na uzorcima površinskog sloja tla izmjereni su pH vrijednost tla (HRN ISO 10390:2005) i udjel elemenata Ca, Mg, K, Na nakon ekstrakcije zlatotopkom (HRN ISO 11466:2004). Na uzorcima uzetim iz genetskih horizonata u pedološkim profilima određeni su granulometrijski sastav tla (HRN ISO 11277:2004), pH vrijednost tla (HRN ISO 10390:2005), udjel organskog ugljika i ukupnog dušika suhim spaljivanjem (HRN ISO 10694:2004; HRN ISO 13878:2004), mineralni sastav tla (XRD) metodom rendgenske difrakcije i udjel elemenata Ca, Mg, K, Na nakon ekstrakcije zlatotopkom (HRN ISO 11466:2004).Za potrebe statističke analize matični supstrat podijeljen je u sedam karakterističnih litoloških cjelina, koje u svom radu prilikom geokemijskih istraživanja potočnih sedimenata Medvednice koriste geolozi Halamić et al. (2001). Litološku cjelinu LIT1 čine parametamorfitne stijene, litološku cjelinu LIT2 ortometamorfitne stijene, litološku cjelinu LIT3 magmatske stijene, litološku cjelinu LIT 4 mezozojske klastične stijene, litološku cjelinu LIT5 tercijarne klastične stijene, litološku cjelinu LIT6 mezozojske karbonatne stijene i litološku cjelinu LIT7 tercijarne karbonatne stijene.Statistička analiza napravljena je u programskom paketu Statistica 7. Za sve analizirane varijable napravljena je deskriptivna statistika: broj uzoraka, minimum, donji kvartil, medijan, gornji kvartil, maksimum, aritmetička sredina, standardna devijacija, koeficijent varijance, standardna pogreška aritmetičke sredine i asimetričnost.Kako bi se isključio utjecaj outlier-a i ekstremnih vrijednosti kao srednja vrijednost uzet je medijan, a međusobne razlike između analiziranih varijabli po litološkim podlogama testirane su Kruskal-Wallisov-im neparametrijskim testom. Greška tipa I (a) od 5% smatrana je statistički značajnom.Najviša pH vrijednost zabilježena je za površinski sloj tla na litološkim podlogama LIT6 i LIT7. LIT6 ima statistički značajno višu pH vrijednost od LIT1, LIT2, LIT3, LIT4 i LIT5, a LIT7 od LIT2, LIT4 i LIT5. Za sve litološke podloge utvrđena je statistički značajna pozitivna korelacija između pH vrijednosti i koncentracije Ca. Utvrđena je i statistički značajna pozitivna korelacija između pH vrijednosti i Mg za LIT1 i LIT5, te pH vrijednosti i K za LIT2 i LIT4. S obzirom na koncentraciju Mg jasno su se izdvojile dvije grupe koje čine LIT4, LIT5 i LIT7 s nižom koncentracijom i LIT2, LIT3 i LIT6 s višom koncentracijom dok je LIT1 između navedenih grupa. S obzirom na koncentraciju K jasno su se izdvojile dvije grupe koje se statistički značajno razlikuju i to LIT2, LIT3 i LIT5 s nižom koncentracijom te LIT4, LIT6 i LIT7 s višom koncentracijom, dok je LIT1 između navedenih grupa.Na otvorenim pedološkim profilima utvrđeni su sljedeći tipovi tala: distrični kambisol, eutrični kambisol, kalkokambisol, pseudoglej obronačni, koluvij i luvisol (udjel po zastupljenosti iznosi 50% – 18% – 14% – 11% – 4% –4%). Općenito se može reći da je humusnoakumulativni horizont na Medvednici plitak – medijan iznosi 3,3 cm, a aritmetička sredina 3,9 cm. Sljedeći, najčešće kambični, horizont je debljine 31 cm, odnosno 33 cm. Raspon udjela org. C u humusnoakumulativnom horizontu kreće se od osrednje humoznog do vrlo jako humoznog tla. Po udjelu ukupnog dušika tlo je dobro do vrlo bogato opskrbljeno, a C/N odnos je povoljan. Prema granulometrijskom sastavu tlo je najčešće praškasto-ilovaste teksture, a na karbonatnoj podlozi nešto teže praškasto-glinovitoilovaste teksture. Udjel pojedinih minerala, te Ca, Mg, K i Na u humusnoakumulativnom i mineralnom horizontu je podjednak, a korelacije između horizonata su statistički značajne (p, Alkali earth metals and alkali metals Ca, Mg, K and Na are a constituent part of the lithosphere rocks and belong among the 8 most abudant elements in the Earth´s crust. They are the results of the weathering of rocks on the surface of the Earth´s crust in the process of pedogenesis. From the aspect of plant nutrition, these elements belong to plant nutrients: K, Ca and Mg belong to macro-elements or essential elements, while Na belongs to beneficial elements.The goal of this research is to establish how the lithological bedrock, or parent material in the area of Medvednica Nature Park affects the Ca, Mg, K and Na content in the soil, and whether their spatial distribution is conditioned by the relief as well as by the lithological bedrock.A total of 181 composite samples were taken in the Medvednica NP forests. Topsoil samples to a 5 cm depth were taken in a regular 1 x 1 km grid. Twenty-eight pedological profiles were opened and evenly distributed to encompass all lithological units. Soil pH values (HRN ISO 10390:2005) were measured in topsoil samples and so was the content of the elements Ca, Mg, K, and Na after extraction with aqua regia (HRN ISO 11466:2004). Determination of particle size distribution in mineral soil material (HRN ISO 11277:2004), determination of soil pH ( HRN ISO 10390:2005), determination of organic carbon and total nitrogen after dry combustion (HRN ISO 10694:2004; HRN ISO 13878:2004), mineral content of the soil (XRD) by X-ray diffraction method and content of the elements Ca, Mg, K and Na after extraction with aqua regia (HRN ISO 11466:2004) were determined in the samples taken from genetic horizons in the pedological profiles.For statistical purposes, the lithological bedrock was divided into seven characteristic lithological units, which were used by geologists Halamić et al. (2001) in their study of stream sediments on Medvednica. Lithological unit LIT1 is made up of parametamorphic rocks, Lithological unit LIT2 is composed of orthometamorphic rocks, Lithological unit LIT3 consists of igneous rocks, Lithological unit LIT4 is formed of Mesozoic clastic rocks, Lithological unit LIT5 is comprised of Tertiary clastic rocks, Lithological unit LIT6 consists of Mesozoic carbonate rocks and Lithological unit LIT7 is made up of Tertiary carbonate rocks.Statistical analysis was performed in Statistica 7 software package. Descriptive statistics was made for all the analyzed variables: number of samples, minimum, lower quartile, median, upper quartile, maximum, mean, standard deviation, coefficient of variation, standard error of mean and skewness. In order to eliminate the effect of outliers and extreme values, the median was taken as the mean value. Mutual differences between the analyzed values per lithological bedrock were tested using the Kruskal-Wallis non-parametric test. Type 1 (a) error of 5% was considered statistically significant.The highest pH value was recorded for the topsoil layer in LIT6 and LIT7. LIT6 has statistically significantly higher pH value than LIT1, LIT2, LIT3, LIT4 and LIT5, while LIT7 has statistically significantly higher pH value than LIT2, LIT4 and LIT5. Statistically significant positive correlation between pH values and Ca concentrations were found in all lithological units. Statistically significant positive correlation between pH values and Mg was also established for LIT1 and LIT5, and between pH values and K for LIT2 and LIT4. In terms of Mg concentration, two groups were clearly identified: one consisting of LIT4, LIT5 and LIT7 with lower concentration, and the other comprising LIT2, LIT3 and LIT6 with higher concentration, while LIT1 is between the two groups.The following soil types were determined in the opened pedological profiles: dystric cambisol, eutric cambisol, calcocambisol, pseudogley on slope, colluvium and luvisol (50% – 18% – 14% – 11% – 4% – 4%). In general, the humus-accumulative horizon on Mt Medvednica is shallow – the median is 3.3 cm, and the mean is 3.9 cm. The next horizon, which is usually cambic, is 31 cm and 33 dm thick. The range of organic C content in the humus accumulative horizon ranges from medium humic to very humic soil. The soil is rich to very rich in total nitrogen, and the C/N ratio is favourable. The soil texture is most frequently silty loam, while on the carbonate bedrock it is of somewhat heavier – silty clay loam. The content of individual minerals, and of Ca, Mg, K and Na in the humus-accumulative and mineral horizon is more or less equal, while the correlation between the horizons is statistically significant (p

Research on oil residuals in lowland forest soil was carried out in 6 sample plots in the lowland forest ecosystem located in an oil field. Four plots were differently affected in terms of discharged oil and the time lapsed after the accident, as well as in terms of micro-relief terrain features. One plot was established in a reclaimed mud ditch site, while the control plot was set up in a micro-relief elevation outside the influence of oil pollution.

SažetakGranulometrijski sastav tla (GST) jedan je od najvažnijih parametara fizičkih značajki tla. Određivanje GST najčešće se temelji na kombinaciji mokrog prosijavanja i pipetiranja, a razlike između pojedinih metoda temelje se na različitim tretmanima uzoraka u pripremi suspenzije za mokro prosijavanje i pipetiranje. Kako je do sada u mnogim laboratorijima korištena metoda pripreme suspenzije s Na-pirofosfatom (i još se uvijek koristi), opravdana je upitnost usporedivosti rezultata s rezultatima normirane metode (norma ISO 11277). S obzirom na specifičnosti dviju metoda, postavljena je hipoteza o postojanju razlika između istih, bilo na razini granulometrijskog sastava ili teksturne interpretacije. U svezi s navedenim, cilj rada je testirati razlike između dviju navedenih metoda.Istraživanje je provedeno na 67 uzoraka šumskog tla, od čega je 15 uzoraka iz njegovog površinskog dijela. Dobiveni rezultati istraživanja pokazali su da nema statistički značajne razlike između metoda za sve uzorke, kako iz mineralnog i iz površinskog dijela tla. Utvrđena je visoka korelacija između udjela svih istovrsnih frakcija određenih po različitim metodama.U interpretaciji teksturnih oznaka na temelju teksturnog trokuta utvrđena je značajna razlika između frakcije pijeska i frakcije praha, dok kod frakcija gline nije bilo statistički značajne razlike. Veći udjel frakcije pijeska utvrđen je interpretcijom na temelju teksturnih klasa po staroj metodi, dok je za prah obrnut slučaj., The purpose of this research was to comparison of two sieving and sedimentation methods for determination of particle size distribution (PSD). Until 2009, PSD was determined at the Faculty of Forestry in Zagreb by a sieve and pipette method after soil preparation using Na-pyrophosphate according to the Pedological manual (old method) (Škorić, 1965). Since the opening of the ecological-pedological laboratory at the Forestry Faculty in 2009, PSD determination has been performed according to the ISO 11277 (2009) Standard. The most important difference between the two methods is that according to the ISO 11227 Standard, pre-treatment is accomplished with hydrogen peroxide which oxidizes the organic matter, so that PSD is determined only in mineral soil particles, while according to the old method, the organic matter was not removed at PSD determination.The purpose of this research was to establish whether there was a difference in the results of PSD determination between the old method and the ISO 11277 Standard in the overall number of samples and particularly in the topsoil. Another goal was to test the difference in the textural interpretation of PSD results obtained by these two methods.For the needs of the analysis, 67 forest soil samples were taken from two areas in Croatia. The two methods were compared in order to determine whether there was a statistically significant difference in the total number of the samples. A comparison was also made to determine whether there was a statistically significant difference between the samples taken from the topsoil layer, since according to ISO 11277 the organic matter largely found in the surface soil part oxidizes.Statistical analysis and t-test revealed no statistically significant difference in any single fraction from the topsoil layer between the old method and ISO 11277. A high correlation was found in the topsoil layer for all the measured fractions (r = 0.98 for coarse sand, r = 0.96 fine sand, r = 0.94 coarse silt, r = 0.84 fine silt and r = 0.97 clay) as well as in the all established samples (r = 0.99 for coarse sand, r = 0.97 fine sand, r = 0.89 coarse silt, r = 0.88 fine silt and r = 0.97 clay).Based on the classification into three main fractions (sand, silt and clay) a higher percentage of sand and a lower percentage of silt was established by the old method compared with ISO 11277. This difference is directly reflected on textural interpretation. No statistically significant difference between the two methods was found for the clay fraction.

Istraživanja su provedena u 95-godišnjoj visokoproduktivnoj sastojini crne johe (Alnus glutinosa Gaertn.) u Podravini. Cilj ovoga rada je istražiti glavna obilježja akumulacije i dinamike ugljika i dušika u sastojini crne johe, kao indikatora stabilnosti ekosustava i održivosti gospodarenja ovom sastojinom. Analiza dinamike i akumulacije ugljika i dušika tijekom godine obuhvatila je istraživanje tla, posebice šumske prostirke i A- horizonta, drva i kore crne johe te lista neposredno nakon odbacivanja. Masa šumske prostirke kreće se od 4,71 Mg ha–1 nakon odbacivanja lista, preko 3,36 Mg ha–1 u proljeće, do 0,51 Mg ha–1 u jesen prije ponovnog odbacivanja lista. Od jeseni do proljeća raste sadržaj ugljika i dušika u A- horizontu, a zatim ponovno opada. Akumulacija ugljika u nadzemnoj biomasi sastojine sredinom ljeta je 214,6 Mg ha–1, a u tlu je prosječno 143,5 Mg ha–1. S druge strane akumulacija dušika veća je u tlu – u nadzemnoj biomasi je 2 Mg ha–1, a u tlu dosiže čak i preko 14 Mg ha–1 (prosječno 13,8). Sveukupna akumulacija organskog ugljika u ekosustavu je 359,5 Mg ha–1, a dušika 15,8 Mg ha–1. Istraživanje je pokazalo da se radi o izuzetno vitalnoj sastojini, očito s izuzetno dobrim ekološkim uvjetima za rast crne johe. Njena se vitalnost i dugoročna stabilnost najbolje odražavaju u postojanom indeksu širine godova u posljednjih 80 godina, što potvrđuje i vrlo velika drvna zaliha, koja za sastojinu starosti 93–98 god. iznosi 751 m3 ha–1 (iznad taksacijske granice od 7 cm)., This research was conducted in a 95-year-old, highly productive stand of black alder growing in the Drava plain in Croatia. The goal was to investigate the main features of carbon-nitrogen accumulation and dynamics in the stand of black alder (Alnus glutinosa (L.) Gaertn.), as an indicator of ecosystem stability and sustainability of managing such stands. Soil physiography was investigated in a permanent sample plot sized 1 ha with growing stock of 751 m3 ha–1. In the course of one season of leaf litter decomposition, the forest floor and soil from the A horizon were sampled on three occasions; the first sampling took place after leaf drop in 2009, the second at the beginning of vegetation (April 2010), and the third before leaf drop (beginning of November 2010). The forest floor mass was determined and so was the carbon and nitrogen content in the forest floor, in the bark, in the physiologically mature leaf and in the soil, as well as the soil pH value. Dendrochronological analysis was performed on black alder wood specimens to determine wood density and carbon and nitrogen content. Data from piezometers set up within the plot for the period 1997–2000 were used to interpret the water regime. According to the research, the soil is Haplic Gleysol (Endoarenic), with a relatively shallow A horizon, of sandy-clayey to loamy-sandy texture, of weakly acidic and in the deeper part weakly alkaline reaction. The water regime is characterized by a shallow and stable groundwater level which occasionally causes shallow (up to 20–30 cm) flooding in the out-of-vegetation period, and does not drop below 130 cm in the vegetation period. The forest floor mass ranges from 4.71 Mg ha–1 after leaf drop, over 3.36 Mg ha–1 in the spring, to 0.51 Mg ha–1 in the autumn before renewed leaf drop, which indicates complete decomposition of black alder leaf litter in a yearly cycle. During this period the C:N ratio decreases from 19 to 14.8. Carbon and nitrogen content in the A horizon increases from autumn to spring, but drops again afterwards. Simultaneously, the pH value significantly drops from autumn to spring, but rises again by autumn. In mid-summer, carbon accumulation in the above-ground biomass of the stand is 214.6 Mg ha–1, while in the soil it is 143.5 Mg ha–1 on average. On the other hand, nitrogen accumulation is higher in the soil: while it is 2 Mg ha–1 in the above-ground biomass, it reaches over 14 Mg ha–1 (13.8 on average) in the soil. Overall accumulation of organic carbon in the ecosystem is 359.5 Mg ha–1, and of nitrogen it is 15.8 Mg ha–1. The research has confirmed that this is an exceptionally vital stand, evidently with excellent ecological conditions for the growth of black alder. The vitality and long-term stability of this stand is best reflected in the stable ring width index in the past 80 years, as confirmed by the very large growing stock amounting to 751 m3 ha–1 for a stand aged 93–98 (above the taxation limit of 7 cm).

Global climate changes, regardless to the origin (natural condition or anthropogenic effect) are actual appearance in Earth. Models predicting global climate changes contain large entropy because they do not include all those factors and their mutual interaction that have direct or indirect effect on climate. According to Hays (1976) global climate changes are effected by regular cycles (so called Milanković cycles) in Earth orbit which appear in almost regular amplitudes at 100000 years. Due to it is observed shift of cold and warm periods in Earth history. Warm periods (interglaciations) repeat every 100000 years, and last approximately 10000 years (Berger, 1981). Precisely shift of warm and cold periods in Earth history significantly effects on composition and quantity of vegetation on Earth (Willis et al., 1999). Due to global changes some tree species show regressive changes (decrease of spatial distribution) of ecological niche, while others show positive direction of changes observed as increase of ecological niche spatial distribution. Climate factors, such as maximum temperature of the hottest month and minimum temperature of the coldest month, as well as precipitation of the driest and the wettest month represent limiting values of climate factors that effect on accrurence of species. Results of the paleobotanic researches point out significant suppression of one tree species when others are spreading. According to research of Reille (1995), common beech (Fagus sylvatica) has during Holocen suppressed common hornbeam (Carpinus betulus) dominating species of the temperate zone European forests in Emiana period (130000 years ago) when forest vegetation was distributed up to toadys boreal areas with dominating tundra vegetation. Also, according to West (1980) in Pastonian period (early to middle Pelistocen) species Picea omorika was distributed up to today’s south of England, and today species population has extremely relict character. When talking about relation between vegetation and climate it should be considered that vegetation indirectly effects and changes climate conditions in certain area, through processes of assimilation and storaging atmosphere CO2 (Laubhann et al., 2008). Therefore changes of climate that is climate factors cause changes of certain part species ecological niche. Whereat it is difficult to distinguish and completely explain only effect of climate factors on species ecological niche and by that spatial distribution of the same. Example for that is species pedunculate oak (Quercus robur) for which accurence especial importance has underground and flood water. But total pedunculate oak (Quercus robur) population from all other species in this research has shown the narrowest range of values according to used climate factors. According to average maximum temperatures of the hottest month pedunculate oak accrue in range at only 2,0 ºC that is 2,3 ºC for average minimum temperature of the coldest month (climate data in period 1950-2000). In contrary to pedunculate oak, common beech (Fagus sylvatica) shows much higher range of average maximum temperatures of the hottest month at 13,6 ºC and 8,9 ºC for average minimum temperature of the coldest month. Exactly this kind of relations point out wideness of certain tree species ecological niche, so that according to extreme temperature values, common beech (Fagus sylvatica) is species of wide ecological

Obična jela jedna je od najvažnijih gospodarskih vrsta drveća u Hrvatskoj. Rasprostranjena je na području Dinarida i na panonskom gorju. Globalne klimatske promjene izazivaju opravdanu bojazan u mogućnost sma njenja ekološke niše obične jele u Hrvatskoj. U ovom su istraživanju analizirani određeni ekološki čimbenici koji izgrađuju ekološku nišu unutar područja pridolaska jele. Korišteni globalni klimatski model podrazumijeva dvostruko povećanje koncentracije stakleničkih plinova (CO2, CH4, N2O, CFC-11 i CFC-12) unutar da našnjega areala obične jele u razdoblju 2000 – 2100. godine, iz čega proizi la zi povećanje prosječne godišnje temperature za ~ 2,5 °C i smanjenje prosječ ne godišnje količine oborina za ~ 152 mm/god. u odnosu na razdoblje 1950 – 2000. godine. Istraživanje je pokazalo kako bi ove promjene mogle pro uzročiti smanjenje ekološke niše obične jele u Hrvatskoj (p>0,9) za gotovo 85 % u odnosu na današnje stanje., The aim of this research is to determine the following: the fundamental ecological niche or potential distribution range of silver fir in Croatia on the basis of selected climatic factors, differences between parts of fir distribution range with reference to the selected climatic factors and changes in the ecological niche in terms of the climate change model for the period 2000 – 2100. Climatic data for the period 1950 – 2000 used in this work were taken from the Worldclime database (Hijmans et al. 2005). Eight climatic variables and relief factors were employed to construct the prognostic model, such as altitute (m), slope (°) and others. Highly correlated variables were rejected. To predict climate changes for the period 2000 – 2100, a CCM3 model (Climate Change Model) was used, which is based on double the current level of greenhouse gases (CO, CH 4, N2O, CFC-11 and CFC-12) (Govindasamy et al. 2003). All climatic data in grid form were 2entered in 30-second resolution (~ 1 km2). Data on fir occurrence in Croatia were taken from the latest research on the distribution of forest sites (Vukelić et al. 2008), ICP plots, phytocoenological relevé database of the Republic of Croatia and management plans. In each plot fir occurrence was graded with binary variables – 1 (present) and 0 (absent). Independent variables used to construct the logistic model and prediction included elevation – Elev (m), slope – Slope (°), mean annual temperature – MeanAnnT (°C), mean annual temperature range – MeanAnnTR (°C), obtained as the difference between the mean temperature of the warmest and the coldest month, then the ratio between the mean monthly temperature range and the mean annual temperature range – IsoTherm (°C), mean temperature of the driest quarter - MeanTDQ (°C), mean temperature of the coldest quarter – Mean TCM (°C), mean annual precipitation quantity – MeanAnnP (mm), mean annual precipitation in the warmest quarter – MeanPWQ (mm) and coefficient of seasonal precipitation variation – PreS (mm). The distribution range of fir was divided into three parts: DIN – the Dinaric part of fir range within the community Omphalodo-Fagetum /Tregubov 1957/ Marinček et al. 1993, ACD – the Dinaric part of acidophilic fir communities (Blechno-Abietetum Horvat /1938/ 1950) and PAN – the Pannonian part encompassing fir range within the community Festuco drymeiae-Abietetum (Vukelić et Baričević 2007). Discriminant analysis (DA) was used to analyze and visualize ecological niches within the range. The prognostic model of ecological niches for the current distribution range of fir and that for the period until 2100 with regard to climate change model was made by means of logistic regression (LOGREG), expressions: p(y)= exp(LP)/(1+exp(LP)), where LP represents linear combination of independent variables (Flantua et al. 2007). According to the research, the current range of silver fir in Croatia does not differ dramatically (p . 0.9) from the potential one. This suggests that longlasting forest management did not contribute to its reduction. However, the selected climatic factors could have a signficant effect on the occurrence of silver fir in Croatia. The prognostic model shows that in conditions of global climate changes its potential range (p = . 0.9) in Croatia could decrease by ~ 85% in the period 2000 – 2100.

We have performed measurements of the cave microclimate, water quality parameters and radon concentration to a depth of -1000 m in Velebita Cave system (Northern Velebit, Croa­tia). The results were analyzed as a function of the cave depth and geomorphological characteristics. Two different air tem­perature gradients were obtained, which can be attributed to a cave morphology and air circulation in the upper part of the pit. The water quality parameters show that the studied waters are poorly mineralized and are of weakly alkaline type. Water chemistry is probably predominantly controlled by the petrog­raphy of the bedrock (limestone) and the cave morphology. Water in the cave is not affected by pollution. The average value of radon concentration is rather low, much lower than in some other Croatian caves.

Ovaj rad rezultat je istraživanja provedenih u polivalentnom šumskom ekosustavu u središnjoj Posavini, na rubu Parka prirode Lonjsko polje. Šuma Žutica je vrlo vrijedan šumsko gospodarski kompleks, retencijsko područje za visoke vode rijeke Save, te u većem dijelu i naftno-plinsko polje. U posljednjih 30-40 godina u ovoj šumi dolazi do pojedinačnog i skupinastog fiziološkog slabljenja i propadanja stabala, ponajprije hrasta lužnjaka. Ove pojave prepoznaju se kao rezultat poremećene ekološke ravnoteže, a povezuje ih se s intenziviranjem gospodarskih aktivnosti na ovom prostoru tijekom navedenog razdoblja. Naša istraživanja postavili smo u funkciju determinacije mogućih uzroka takvih pojava povezanih s kemijskim i biološkim stanjem tla. Usmjerili smo ih u analizu i monitoring kemijskih i bioloških značajki površinskog dijela tla najnižih lokaliteta (mikrodepresija). Istraživana je koncentracija fosfora i kalija te elemenata u tragovima, zatim mineralnih ulja i ukupnih lipoidnih tvari te mikrobiološka aktivnost. Pokazalo se da tlo šume Žutica nije onečišćeno na većim površinama, te se onečišćenje kao takvo ne dovodi u vezu sa propadanjem stabala na većim površinama. Permanentni izvori onečišćenja na razini vrlo slabe opterećenosti povezuju se sa saniranim isplačnim jamama, no oni se vjerojatno ne odražavaju na širi prostor Žutice. Mikrobiološki parametri upućuju na populacije adaptiranih mikroorganizama, koji su vrlo učinkoviti u biorazgradnji ulja na takvim malim površinama., This work is the result of research undertaken in a polyvalent forest ecosystem situated on the edge of Lonjsko Polje Nature Park in central Posavina. The forest of Žutica is a very valuable forest management complex. Being a retention area for high waters of the River Sava, its larger part is also an oil-gas field. The last 30 to 40 years have seen physiological weakening and dieback of single trees and groups of trees and of pedunculate oak in particular. These phenomena, resulting from the disturbed ecological balance, are associated with intensive commercial activities in the area during the period mentioned above. The basic hypothesis is that the ecosystem has undergone complex disturbance, which is associated with the following: oil well fluid spills in the past 40 years, hydrological changes resulting from a dense road network built to serve the needs of the oil-gas field and forest management. To a lesser extent, it is also linked with hydrological and microbiological changes associated with occasional retention of floodwater. The purpose of our research was to identify some possible causes of these occurrences from the aspect of chemical and biological soil condition. We focused on the analysis and monitoring of chemical and biological properties of the surface soil in the lowest localities (microdepressions). Phosphorus and potassium concentrations and trace elements were investigated, and so were mineral oils and total lipoidal substances, as well as microbiological activity. The research is based on twice-yearly measurements of the above parameters in 14 points in those microdepressions whose location (e.g. in relation to some possible contamination with oil well fluids), as well as the occurrence of pedunculate oak dieback has led us to conclude that they represent micro-sites most exposed to the mentioned impacts. Although the forest of Žutica is a homogeneous area in geographic and relief terms, the surface part of the soil in this forest has proved to be physiographically highly heterogeneous. With regard to oil carbohydrates, the soil is not contaminated over larger areas. Therefore, contamination as such is not considered responsible for tree dieback over larger areas. Permanent sources of pollution at the level of very weak contamination are associated with restored mud ditch, but they are probably not reflected on the wider Žutica area. Microbiological parameters indicate populations of adapted micro-organisms which ar The concentration of trace elements in the soil is within geogenic values, whereas some occasional anomalies occur in the locations which have been recovered after oil well fluid spills.

Od 4. do 19. kolovoza 2007. godine održana je treća po redu ekspedicija u “Velebitu”. Na dnu Vertikale Divke Gromovnice na -580 m dubine ispenjana je vertikala od 34 m kojom se došlo na policu odakle treba nastaviti s penjanjem u dimnjak, ali se stalo s istraživanjem jer još uvijek postoje dijelovi s većom perspektivom. Istražena je dvorana na -614 m. Nastavljeno je s istraživanjem u najdubljim dijelovima jame pa je tako pronađen meandar nazvan Potjehova potraga nakon kojeg se došlo u Podzemljarovu dvoranu na -1026 m. Snimljen je polusatni film o ekspediciji, sakupljen je biološki materijal, te su obavljena fizikalna i kemijska mjerenja koja će nakon obrade biti objavljena. Nakon istraživanja u 2007. godini jamski sustav Velebita dubok je - 1026 m, poligonska duljina je 2560 m, a tlocrtna duljina 965 m.

Ulaz u jamu Xantipa pronašli su 23. srpnja 1994. godine slovački speleolozi Brano Šmida i Jano Vykoupil. Iste je godine u tri akcije jama istražena do dubine od 313 m. U 1995. godini nastavljeno je istraživanje jame Xantipa tijekom pet dana, no krajnja dubina nakon proširivanja suženja povećana je za samo 10 m (-323 m).Promjer ulazne vrtače Xantipe veći je od 200 m, pa svojom veličinom i izgledom predstavlja jednu od atraktivnijih i impozantnijih krških pojava na Hajdučkim i Rožanskim kukovima. Sve stijene ulazne vrtače su vertikalne, s jakim pukotinama i velikim škrapovitim udubljenjima. Zapadna, u donjem dijelu prevjesna, stijena vrtaće visoka je oko 150 m. Slovački su se speleolozi u ulaznu vrtaču Xantipe spustili s jugoistočne strane. Prvim skokom od 15 m dolazi se na strmu travnatu kosinu, iz koje se prelazi u 30 m dugu vertikalnu pukotinu. Odavde se s krševito-glinovite police 5-metarskim skokom dolazi na prostranu snježnu, mjestimično zaleđenu površinu, dimenzija 75 x 35 m. Snježna je ploha od ruba stijena odvojena 4 m dubokim i 1 do 2 m širokim otopljenim jarkom. Pod jugozapadnom stijenom vrtače, 4 m iznad dna ledene plohe, nalazi se špiljski otvor dimenzija 5 x 3 m. On prelazi u vertikalu od 15 m, koja završava ledom. Direktno ispod visoke sjeverozapadne prevjesne stijene nalazi se dvostruki ulaz, širok 3 i dug 12 m, koji vodi u 200-metarsku vertikalu. Ulazni dio vertikale ima izduženi oblik i širok je 1 do 2 m. Na 60 m dubine prostor se proširuje, pa širina iznosi 10 do 12 m, tako da je poprečni presjek ovalan. Na ovoj dubini završava ledeni čep, dok su stijene duž cijelog profila do dubine od 220 m i dalje obavijene ledenom korom debljine 2 do 3 cm. Na 100 m dubine poprečni profil produljuje se na 20 m i takav se pruža do kraja vertikale. Na dnu ulazne vertikale nalazi se veliki ledeni blok dimenzija 8 x 4 x 5 m, koji se ovamo srušio između dvije ekspedicije, 1994. i 1995. godine. Jama se dalje nastavlja ledenom kosinom dugom 50 m, smještenom u 8 m visokom i 2 do 4 m širokom kanalu nagiba 40°, nazvanom Bob staza. Kanal se postupno širi s lijeve strane dimnjakom profila 4 x 15 m. Stijene ovog kanala bile su obložene ledenim injem. Završni dijelovi jame imaju oblik 15 m dugog pukotinskog prostora visine 20 m i širine oko 3 m. Na dnu ove pukotine bilo je 40 cm široko suženje zatrpano blokovima. Ova dubina (313 m) dosegnuta je 1994. godine. U 1995. godini blokovi su maknuti i prošlo se u 10-metarsku pukotinsku vertikalu širine 1,5 m, koja završava izuzetno uskim suženjem širine 3 do 5 cm. Ovaj se opis ulazne vrtače, odnosno ledene police, odnosi na zapažanja iz 1994. godine. Već sljedeće godine ulazni otvori spojili su se u jedan jedinstveni otvor. Čitava situacija narednih se godina promijenila, pa je cijela ledena ploha na dnu ulazne vrtače bila prekrivena blokovima, kršjem i glinovitim nanosom. Ledena se površina smanjila, a rubni jarak između stijena i ledene površine se povećao. Istraženi prostori u jami Xantipi su prema Šmidi (1999) vrlo vjerojatno samo rubni dijelovi velikog podzemnog sustava. On pretpostavlja da se genetski starije, paralelne vertikale nalaze neposredno ispod velikog ledenog čepa, te da su one međusobno spojene bočnim prolazima. Slićna situacija zamijećena je u mnogim jamama na sjevernom Velebitu, a najbolji primjer je Slovačka jama. Za vrijeme vrućih ljetnih dana na ledenoj plohi u dnu ulazne vrtače Xantipe izmjerena je temperatura od +1,2 °C (Košel), a dno vrtače čak niti u podne nije bilo osvijetljeno direktnim sunčevim svjetlom. Noću, za vedrog vremena, inverzni se uvjeti još jače ističu - stvara se gusta magla, čija gornja granica seže 20 m visoko iznad ledene plohe. Po izlasku iz magle osjeća se nagla temperaturna promjena, veća i od 10 °C. U ulaznoj vertikali Xantipe prisutna je stalna nakapnica, a osjeća se i stalno strujanje zraka u smjeru unutrašnjosti jame. Za manje sunčanog vremena strujanje zraka slabije je izraženo. Na dnu jame, u oba suženja osjeća se jako strujanje zraka u smjeru izlaza. U samoj jami je prema navodima Šmide (1999) temperatura ispod 0 °C.

U razdoblju od 30. srpnja do 14. kolovoza 2005. godine 26 speleologa izmjenjivalo se u istraživanjima u Jamskom sustavu Velebita u kojem je dosegnuta dubina od -941 metar. Ova je jama treća po dubini u Hrvatskoj i ima podzemnu vertikalu od 513 metara. Jama Velebita prošle je godine istražena do dubine od -580 m, a ove godine četrdeset metara iznad starog dna pronađen je ulaz u nove dijelove jame. Velika količina vode i uski prolaz zaustavili su speleologe na dubini od -941 m. U istraživanju su osim članova SO PDS Velebit (34) iz Zagreba sudjelovali i speleolozi iz SO HPD Mosor iz Splita (2), SO PD Dubovac iz Karlovaca (1), SD Samobor (1), Hrvatskog biospeleološkog društva (2) i SO HPD Željezničar iz Zagreba (1), te PD Castrum Iovia iz Ludbrega (1). Vođa ekspedicije bio je Darko Bakšić.

Potencijalni ulaz u novu jamu otkriven je 31. srpnja 2003 tijekom tradicionalnog speleološkog logora koji se svake godine održava na Sjevernom Velebitu. Dobila je ime Velebita. Prvih 105 m jame je koljenaste morfologije nakon koje se otvara velika vertikala istražena do 376 m dubine. Nastavak istraživanja se očekuje u 2004. godini.

Istraživanja Lubuške jame provedena su tijekom 12. - 19 rujna 2000. i 01. - 14. kolovoza 2001. godine. Poljski speleolozi iz speleoloških društava Bobry Żagań i Gawra udružili su snage s članovima SO PDS Velebit da bi istražili jamu. Ulaz je otkriven 11. rujna 2000. godine dok su speleolozi istraživali na lokacijama jugoistočno od Trojame, jednog od ulaza u jamski sustav Lukina jama - Trojama. Istraživanja jame (pod imenom SOV-PL2) počela su već idućeg dana. Trebalo je 6 dana za izradu nacrta jame do dubine -262 m, iako su se speleolozi spustili još 50 m dublje. Zbog manjka opreme i jakih kiša istraživanja su prekinuta da bi se nastavila u rujnu iduće godine kada je osvojen veliki meandar i jama je istražena do 521 metra dubine (Furtak 2001, Furtak and Pilecki 2001). Tlocrt Lubuške jame pokazuje da se jama približuje sustavu Lukina jama - Trojama, što otvara mogućnost spajanja s meandrom u Trojama ispod 400 m dubine (horizontalno se nalaze na 100 m udaljenosti). U tom slučaju dubina sustava bi se povećala na 1412 metra s obzirom na ulaz u Lubušku jamu, koji se nalazi na 1495 m nadmorske visine.

Tijekom hrvatsko-francuske ekspedicije „Crikvena 2003“ speleolozi iz SO PDS Velebit iz Zagreba pronašli su 31. srpnja ulaz u jamu Velebitu. S obzirom da su glavni ciljevi ekspedicije bili izrada topografskih nacrta i nastavak speleoloških istraživanja u jami Meduza, Velebiti se nije pridalo mnogo pažnje, te je nažalost istražena samo do 376 m dubine, gdje se stalo u velikoj verikali nazvanoj „Vertikala Divke Gromovnice“. Istraživanja Velebite nastavljena su iduće godine u suradnji s Javnom ustanovom Nacionalni park Sjeverni Velebit u sklopu ekspdicije „Velebita 2004“, koja je trajala od 31. srpnja do 14. kolovoza 2004. godine. Četvrti dan ekspedicije doseglo se 580 m dubine, i to prolaskom velike vertikale od 469 m. U početku se činilo da nema daljnjih prolaza na dnu, te su započeta istraživanja u bočnom meandru i vertikalama od 100 do 200 m dubine. Nova jama pronađena ovim istraživanjima nazvana je Dva javora i povezana je s jamom Velebita prečnicom nazvanom Žrekova prečka u Vertikali Divke Gromovnice, trećoj najvećoj vertikali na svijetu ili točnije najdubljom podzemnom vetikalom na svijetu, koju slijedi Hohllenhohle vertical u Austriji (450 m) na drugom mjestu. U sjeveroistočnom dijelu dvorane na dnu Velebite nađeno je 15 čak primjeraka pijavice Croatobranchus mestrovi, što je nabrojnija populacija dosad. Osim najdublje točke u jami koja je na 580 m dubine, vertikale unutar Velebite duboke su 161, 114 i 110 m, dok najdublja vertikala u Dva javora iznosi 228 m dubine (tj. 211 m dubine od ulaza u jamu Dva javora, koji je sedam metara niži od ulaza u jamu Velebitu). Za vrijeme ekspedicije koju su organizirali Speleološki odsjek PDS Velebit i Komisija za speleologiju Hrvatskog planinarskog saveza ušlo se u i istražilo još tri manje jame. Osim članova navedenog društva, u ekspediciji „Velebita 2004“ koju je vodio Darko Bakšić, sudjelovali su članovi SO HPD Mosor, Hrvatskog biospeleološkog društva i SO PD Dubovac.

Markovski ponor je špilja koja je istraživana prije 30-ak godina. Od tada su se mnoge stvari u speleološkim tehnikama promijenile. Nova istraživanja koja su obavili speleolozi SO Velebit i SO Željezničar rezultirali su novom dužinom koja je sada 1725 m i nova dubina od -69 m. Također, tijekom istraživanja, speleolozi su ispenjali 96 metara vertikala u 7 penjeva. Istraživanja su daleko od kraja, budući da postoji mnogo prolazi u nove, neistražene kanale....

Pri rekognosciranju terena, 28. srpnja 1995., slovački speleolozi B. Šmida i M. Griflik pronašli su ulaz u Slovačku jamu. Nakon devetodnevnih speleoloških istraživanja Slovaci se spustili do "dna" na dubini od 514 m. Tom prilikom zamijećen je horizontalni kanal, -350 m. Tijekom ljeta 1996. Slovaci zajedno s kolegama iz Planinarskog društva Sveučilišta "Velebit" nastavljaju istraživanja Slovačke jame u horizontalnom kanalu na 350 dubine. Tri tjedna kasnije spustili su se do dubine od 1000 m. Tada je prvi put u ovoj jami viđena endemska troglobiontna pijavica Croatobranchus mestrovi. U listopadu 1996. grupa zagrebačkih speleologa iz planinarskih društava "Velebit" i "Željezničar" u suradnji s Hrvatskim prirodoslovnim muzejom spušta se u jamu do dubine 570 m kako bi za znanstvena istraživanja skupila jedinke pijavice. Iako taj put pijavica nije nađena, pronađeni su ostaci nepoznate vrste kornjaša iz roda Radziella. Radi nastavka istraživanja jame, 1998. i 1999. ostvarene su zajedničke hrvatsko-slovačke ekspedicije pod vodstvom Darka Bakšića i Branislava Šmide. 1998. Slovačka jama istraživana je u dva odvojena kanala. Slovački su speleolozi u nastavku dvorane Pompeji dosegli dubinu od 1022 m, dok su se u Kankulovskom kanalu čiji je nastavak nazvan Velebni kanal) hrvatski speleolozi spustili do dubine od 1268 m. U 1999. godini, nakon osmodnevnog boravka na dubini od 1254 m, hrvatski speleolozi istražili su novih -670 m horizontalnih kanala, te su dosegli dubinu od 1301 m. Slovački kolege u višim dijelovima jame otkrivaju nove dijelove nazvane Žumpa, dubine 866 m, i Hermanova studnja, dubine 530 m. Tom dubinom Slovačka jama zauzima 17. mjesto na listi najdubljih jama svijeta. Značajna je i duljina ovoga objekta, koja iznosi 2414 a poligonska duljina 5548 m., While surveying the terrain on the 28th July 1995, Slovak cavers B. Šmida and M. Grifik found the entrance of a Slovak cave pot-hole. After nine days of speleo exploration, Slovaks reached the "bottom" at the depth of-514 m. They have also noted the side passage at the depth of-350 m. During summer 1996 Slovaks, together with their colleagues from the University Mountaineering Society "Velebit", continued the exploration of the Slovak cave in the horizontal passage at 350 m of depth. Three weeks later they reached depth of -1000 m. For the first time they observed in the cave an endemic troglobiontic leech named Croatobranchus mestrovi. In October 1996 a group of cavers from Zagreb, members of the societies "Velebit" and "Željezničar", in co-operation with the Croatian Natural History Museum, descended into the cave to the depth of 570 m with aim to collect a specimen of the leech for further scientific research. But, instead of a leech, they found the remnants of the unknown Coleopteran species of genus Radziella. In 1998 and 1999 Croatian-Slovak expeditions, under the leadership of Darko Bakšić and Branislav Šmida, took place with aim to continue survey of the cave. In 1998 Slovak cave was surveyed in two separated passages. Slovak cavers by the end of cavern Pompeji reached the depth of 1022 m, while the Croatian cavers reached in Kalkulovski passage (the continuation of the passage is named Velebni kanal) the depth of 1268 m. In 1999, after eight days of long surveying at the depth of 1254 m, Croatian cavers explored 670 new metres of horizontal passages and reached the depth of 1301 m. Slovak cavers discovered in upper parts passage named Zumpa at the depth of 866 m and Hermanova studnja at -530 m. This depth makes Slovak cave the 17th deepest in the world at the list of the deepest world caves. Important values are length that is 2414 m and included length of 5548 m., Bei der Rekognoszierung des Terrains am 28. Juli 1995 fanden die slowakischen Spelaeologen B. Šmida und M. Griflik den Eingang in die "Slowakische Grube". Nach neun Tagen spelaelogischer Untersuchungen ließen sich die Slowaken bis zum Boden der Grube auf der Tiefe von 514 herab. Dabei wurde ein waagrechter Kanal auf-350 m gefunden. Im Laufe des Sommers setzten die Slowaken mit den Kollegen aus der Universitaets-Alpinisten-geselleschaft "Velebit" die Untersuchung in dem waagrechten Kanal fort, auf der Tiefe von 1000 m, und dann wurde zum ersten Mai der endemische dreiglobionte Egel Croatobranchus Mestrovi gesehen. Im Oktober 1996 ließ sich eine Gruppe der Zagreber Spelaeologen aus den Alpinisten-Gesellschaften "Velebit" und "Željezničar" (Eisenbahner) in Mitarbeit mit dem kroatischen naturwissenschaftlichen Museum in die Tiefe von 570 m herab, um die Exemplare des Egels zu sammeln und zu untersuchen. Obwohl diesmal der Egel nicht gefunden wurde, wurden Reste einei unbekannten Art Hartfluegel aus dem Geschlecht der Radziella aufgefunden. Um das Untersuchen der Grube fortzusetzen, wurden gemeinsame kroatisch-slowakische Expeditionen unter Fuehrung von Darko Bakšić und Branislav Smid organisiert. 1998 wurde die "Slowakische Grube" in zwei getrennten Kanaelen untersucht. Die slowakischen Spelaeologen erreichten in der Fortsetzung des Saals "Pompei" die Tiefe von 1022, und die kroatischen Spelaeologen ließen sich in den "Kankulovski Kanal" bis zur Tiefe von 1268 m herab (seine Fortsetzung wurde "Velebni Kanal" genannt). Im Jahre 1999, nach 8 Tagen des Verweilens auf der Tiefe von 1254 m, untersuchten die kroatischen Spelaelogen noch 670 m der waagrechten Kanaele und erreichten die Tiefe von 1301 m. Die slowakischen Kollegen entdeckten in hoeheren Teilen der Grube neue Teile, die "Žumpa" (-866) und "Hermanova Studnja" (-530) gennant wurden. Mit dieser Tiefe nimmt die Slowakische Grube den 17. Platz auf der Liste der tiefsten Gruben der Welt ein. Es ist auch die Laenge dieser Grube charakteristisch, sie ertraegt 2414 m, und ihre polygonische Laenge ertraegt 5548 m.

Opisan je pregled speleološkog istraživanja Slovačke jame, morfologija jame s nacrtom, geološka opažanja i mjerenja starosti siga 14C izotopnom metodom, te biospeleološke značajke jame.