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1.
Spremljanje sezonske dinamike bentoških organizmov v dveh visokogorskih jezerih v Julijskih Alpah
Manuel Persoglia, 2023, magistrsko delo

Opis: Cilj projekta je bil ugotoviti podobnosti oz. razlike in sezonsko dinamiko bentoških organizmov v dveh visokogorskih jezerih v Julijskih Alpah, ki ležita na različni nadmorski višini: Rabeljsko jezero (969 m n. m.) – Italija in Krnsko jezero (1391 m n. m.) – Slovenija. Vzorčenje je potekalo po metodi »kick sampling« s pomočjo ročne mreže za zbiranje vodnih nevretenčarjev v vodi do globine približno 0,5 m in okoli 2 m od obale jezera, odvisno od oblike in sestave jezerskega dna. Vzorčenje je potekalo na različnih podlagah, da je bilo zajetih čim več mikrohabitatov. Končni cilj projekta je bil prikazati dinamiko posameznih vrst vodnih nevretenčarjev glede na sezono. Hkrati smo iskali razlike v vrstni sestavi in pogostosti živali med obema jezeroma. V petih vzorčevalnih obdobjih med letoma 2021 in 2022 smo na osmih različnih mestih nabrali 40 vzorcev. Skupno je bilo najdenih 330 osebkov bentoških organizmov iz enajstih družin, ki smo jih uvrstili v osem višjih taksonov, in sicer Diptera (dvokrilci), Ephemeroptera (enodnevnice), Gastropoda (polži), Megaloptera (velekrilci), Odonata (kačji pastirji), Oligochaeta (maloščetinci), Plecoptera (vrbnice), Trichoptera (mladoletnice). Najbolj prisotni sta bili skupini dvokrilcev in maloščetincev.
Ključne besede: Visokogorska jezera, bentoški organizmi, Julijske Alpe, Rabeljsko jezero, Krnsko jezero
Objavljeno v RUNG: 30.08.2023; Ogledov: 1071; Prenosov: 9
.pdf Celotno besedilo (1,93 MB)

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Regional biodiversity and seasonal dynamics of the bacterial communities in karstic springs of Slovenia
Maja Opalički Slabe, 2019, doktorska disertacija

Opis: Information on groundwater’s natural bacterial communities is important for evaluating pristine groundwater’s quality, as environmental changes potentially lead to alterations in bacterial community structures. In four seasons, 15 hypothetically pristine springs across five karst eco-regions in Slovenia (Central Europe) were analysed during their low discharge, and their basic physical and chemical parameters were recorded. The diversity of bacterial community structures was assessed with a terminal restriction fragment length polymorphism fingerprinting method. Total cell counts as bacterial abundance and electron transport system activity as bacterial respiratory activity were used for quantitative evaluation of bacterial communities. To detect anthropogenic pollution, spring water was tested by the cultivation of coliform bacteria and Escherichia coli (E. coli). Results indicate distinct regional differences in environmental parameters, bacterial respiratory activity, presence of coliforms and E. coli, bacterial abundances, and qualitative bacterial community structures, but there were no regional differences in the numbers of operational taxonomic units and biodiversity indices (Shannon-Wiener’s and Simpson’s diversity index, Buzas and Gibson’s evenness). The analysis of seasonal environmental parameters showed significant differences in dissolved organic carbon and pH, and also significant changes in bacterial respiratory activity and abundances, as well as differences in bacterial community structures, the numbers of operational taxonomic units, and biodiversity indices. No seasonal variations were shown for coliforms and E. coli. Despite seasonal oscillations, regional differences prevailed among five karst eco-regions and indicate a significant influence on the qualitative and quantitative aspects of groundwater bacterial community structures. The study confirmed both regional and seasonal differences in groundwater bacterial community structures, which should be included in further sustainable management plans of the aquifers.
Ključne besede: karst springs, bacterial community structure (BCS), terminal restriction fragment length polymorphism (T-RFLP), total cell counts (TCC), electron transport system activity (ETSA)
Objavljeno v RUNG: 26.06.2019; Ogledov: 4102; Prenosov: 191
.pdf Celotno besedilo (3,76 MB)

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STRUCTURE AND FUNCTIONING OF THE HYPORHEIC ZONES IN THE GRAVEL-BEDS OF FIVE RIVERS IN RELATION TO CATCHMENT LAND USE
Barbara Debeljak, 2018, doktorska disertacija

Opis: The hyporheic zone has been recognised as a functionally important component of streams and rivers. Due to increasing human impact on ecosystems, studies that assess ecological responses of the hyporheic zone are of great importance. The objectives of the thesis are to study the responses of abiotic parameters, sediment biofilm characteristics (the in situ respiration (R), potential respiratory activity (ETSA), protein content), and invertebrate assemblages (analysed as total assemblages, EPT assemblages and Copepoda assemblages) in the hyporheic zones related to different land use patterns (forest, agricultural and urban areas). The focus of study also includes the impact of clogging. This research is comprised of three sampling campaigns conducted in summer (2013), winter (2013) and spring (2014) in five pre-Alpine Slovenian rivers. For each river, three or six sampling locations were chosen in the downwelling hyporheic sections of three dominant land uses (forest, agriculture and urban) within a 250 m wide impact zone. Three sampling points per location were sampled from two depths (5 –15 cm and 20 – 40 cm) using PVC tube and Bou-Rouch method. The results indicate a significant spatial and temporal heterogeneity of measured hyporheic zone components. Physical and chemical parameters of water revealed moderate response to land use. The effect of land use on the amounts of suspendable fine sediments in the hyporheic zone was observed only in the spring season. The effect of land use was significant for in situ R during summer and spring and for ETSA and protein content in all seasons, indicating that land use, such as agriculture, near a stream can affect biogeochemical processes. A relatively high diversity of invertebrates was recognised in the hyporheic zone. Groups such as Nematoda, Oligochaeta, Copepoda and Chironomidae were found in all samples. Within EPT taxa as representatives of occasional hyporheic invertebrates, 35 taxa were identified. Within Copepoda, as representatives of permanent hyporheic invertebrates, 14 Cyclopoida and 19 Harpacticida taxa were identified. Both assemblages were characterised by high abundance of widespread taxa, such as Baetis sp., Leuctra sp., Diacylops cladestinus and Acanthocyclops hispanicus. Statistically significant differences were observed among land uses in Copopoda assemblages but not for EPT assemblages. Calculated metrics on EPT assemblages showed statistically significant differences in land use in the number of EPT taxa, Simpson index and Shannon-Wiener index. Within Copepoda assemblages, the numbers of Copepoda taxa were significantly higher at forest sites. The hyporheic assemblages were relatively well explained by environmental parameters. This thesis presents a comprehensive study of the hyporheic zone, where both structural and functional measures reflected the ecological integrity of the hyporheic zone. The in situ R and ETSA were generally higher in agriculture stream reaches, indicating that hyporheic functioning responded to nutrients and carbon runoff-derived inputs from agricultural activities within the 250 m impact zone. Thus functional parameters in situ R and ETSA were more efficient indicators of land use impacts in the hyporheic zone than physical and chemical parameters. The potential of using hyporheic invertebrates as bioindicators of environmental conditions was confirmed but should be tested with wider gradients of environmental parameters. The results obtained by this study underlined that the hyporheic zone should be integrated as an additional ecological element by assessing the ecological conditions of surface water bodies.
Ključne besede: hyporheic zone, ecosystem functioning, land use, biofilm characteristics, invertebrates
Objavljeno v RUNG: 02.07.2018; Ogledov: 4249; Prenosov: 161
.pdf Celotno besedilo (5,31 MB)

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THE INCIDENCE OF NEW ECOSYSTEMS (EE – EMERGING ECOSYSTEMS) IN THE KARST BIOSPHERE RESERVE : GROUP PROJECT, FINAL REPORT
Klemen Cotič, Matej Pogorelc, Matjaž Reya, Barbara Šavli, Nika Feigina, Merisa Kapić, Ӧzkan Karaçam, Mariya Perepelytsya, 2017, druge monografije in druga zaključena dela

Opis: The need of wood for building and heating, the extensive grazing and population growth in the 18th and 19th centuries led to turning the Karst area in Slovenia into a bare land. In the 19th century organised reforestation started which was successfully performed with Black pine (Pinus nigra J. F. Arnold). Later on, the reforestation was replaced by the process of spontaneous afforestation. The successfulness of reforestation with Black pine also made it possible for the native tree species to grow. The abandoning of the use of agricultural land also contributes to the spontaneous afforestation. In this project we determined the changes in forest cover through time. We used aerial photographs from the years 1957, 1975, 1985 and 2015. By drawing polygons on the maps in the QGIS programme on the areas that are covered with forests, are overgrown or are used for agricultural purpose we compared the areas from the maps of different years. We found out that the area covered with forest had increased by more than 50 % from the year 1957 to 2015. The increase in the area of forest cover due to afforestation provides new habitats for fauna and flora to live in.
Ključne besede: Karst, afforestation, new habitat, Black pine, human impact
Objavljeno v RUNG: 07.11.2017; Ogledov: 5286; Prenosov: 0
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Ecological niche relations of indigenous and invasive crayfish (Astacoidea) in Slovenia
Martina Jaklič, 2016, doktorska disertacija

Opis: In this study, realised and fundamental niches were combined between studied ICS (Austropotamobius torrentium (Schrank, 1803), Austropotamobius pallipes (Lereboullet, 1858), Astacus astacus (Linnaeus, 1758)) and NICS (Pacifastacus leniusculus (Dana, 1852), Orconectes limosus (Rafinesque, 1817), Cherax quadricarinatus (von Martens, 1868)). The realised niche was described by population characteristics. P. leniusculus showed similar annual cycle than ICS, but on the other hand it showed higher population density, shorter breeding period, and better individual condition (estimated with SMI) comparing to the ICS. These are its advantages over ICS, which increase its potential for the invasiveness. The most pronounced this threat is to A. astacus, with which it has the most similar/ overlapping realised niche. Similar was observed comparing the ICS and NICS fundamental niches presented by selected physiological measurements (maximal food (Cmax) and oxygen consumption (Rn), concentration of haemocyanin in haemolymph (Hc), electron transport system (ETS) activity and potential growth scope (PGS). As a result of higher plasticity and adaptation to varied environmental conditions, NICS expressed different physiological response to temperature at cellular (ETS activity) and organism (Cmax, Rn, PGS) level. Similar fundamental characteristics (expressed with thermal optimums) were found between P. leniusculus and ICS, while optima for O. limosus and C. quadricarinatus were more narrow and higher (above 22 °C and 30 °C). Modelling of thermal niches showed differences mostly among species on cellular level (in ETS activity). This was a new approach and support for better estimation of success and proliferation of new invaders. Furthermore, C. Quadricarinatus, found for the first time as established population in temperate climate of Europe (in Slovenia in 2009), was used in this study, as a model organism, to show that the combination of fundamental and realised thermal niche, as well as ecophysiological and field research can constitute an important input to the model for estimating the risk associated with C. quadricarinatus. It is rarely possible to observe the development of new invaders in the new environment, therefore monitoring of the C. quadricarinatus through the three growth period (1-lag phase, 2-log phase, 3-stable phase), was unique example in the invasive biology. After extremely increasing the population in 2011 and 2012 (for 7.7 - 10.1 % per month) the population developed and stabilised in March 2012. Based on these high numbers of field and lab data, the TIRI (Thermal Invasive Risk Index) was developed to produce instant results that may be satisfactory for evaluation of different degrees of invasiveness. We found that the oxbow lake Topla had no lethal days (no. of days when water temperature is below or above temperature of death) in comparison with the adjacent rivers where the number of lethal days probably constitutes an important barrier for species spreading. Therefore, we concluded that C. quadricarinatus could potentially reproduce in the adjacent rivers, but survival of the brood is doubtful, especially due to previous results concerning critical min/max temperatures.
Ključne besede: potočni raki, jelševec, koščak, koščenec, signali rak, trnavec, rdečeškarjevec, sezonska dinamika, termalna toleranca, temeljna ekološka niša, realizirana niša, potencialna invazivnost
Objavljeno v RUNG: 24.11.2016; Ogledov: 5755; Prenosov: 349
.pdf Celotno besedilo (4,73 MB)

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VPLIV KOPALCEV NA BENTOŠKE NEVRETENČARJE V OBALNEM PASU BOHINJSKEGA JEZERA
Vanja Kristančič, 2016, diplomsko delo

Opis: V letu 2008 smo v litoralnem pasu Bohinjskega jezera od junija do semptembra trikrat vzorčili na sedmih izbranih mestih, da bi ocenili vpliv kopalcev na številčnost bentoških nevretenčarjev (makroinvertebratov). Primerjali smo številčnost populacij med vzorčnimi mesti in pripadajočim referenčnim mestom (referenčno mesto 1 z vzorčnimi mesti 1 in 2 ter referenčno mesto 2 z vzorčnimi mesti 3, 4 in 5). Zajeli smo 21 plastenk z bentoškimi vzorci (vsaka predstavlja 0,64 m2 površine litoralnega pasu v jezeru na globini 0,5 m dveh referenčnih in petih vzorčnih mest, ki predstavljajo s turisti različno obremenjene dele vzhodnega obrežja jezera (Kopalno območje Fužinski zaliv)). S presejanjem smo ločili vse osebke, večje od 2 mm. Po določanju organizmov smo označili 336 epic za 13 skupin: Nematoda (gliste), Bivalvia (školjke), Gastropoda (polži), Oligochaeta (maloščetinci), Hirudinea (pijavke), Ephemeroptera (enodnevnice), Plecoptera (vrbnice), Odonata (kačji pastirji), Coleoptera (hrošči), Heteroptera (stenice), Megaloptera (velekrilci), Trichoptera (mladoletnice), Diptera (dvokrilci). S pomočjo primerjave gibanja populacij med vzorčnimi mesti in ustreznim referenčnim mestom smo določili 3 kritična mesta (pri čolnarni, pri cerkvi sv. Janeza Krstnika in pri urejenem delu kopališča) in 3 kritične skupine (gliste, maloščetinci in dvokrilci).
Ključne besede: Bohinjsko jezero, Kopalno območje Fužinski zaliv, bentoški nevretenčarji, vpliv kopalcev.
Objavljeno v RUNG: 28.09.2016; Ogledov: 5695; Prenosov: 243
.pdf Celotno besedilo (1,55 MB)

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Razširjenost in velikost populacije nove invazivne vrste v Blejskem jezeru: školjka trikotničarka (Dreissena polymorpha (Pallas, 1771))
Tina Hrovat, 2015, diplomsko delo

Opis: Ena izmed invazivnejših tujerodnih vrst na svetu je školjka Dreissena polymorpha (Pallas, 1771), slovensko potujoča trikotničarka ali školjka trikotničarka (Remec–Rekar, Š., 2013). Naseljuje jezera, rezervoarje, bazene in lagune. Širjenje je opaženo predvsem v jezerih, kjer je velika številčnost fitoplanktona in je alkalna voda bogata s kalcijem in magnezijevimi solmi (Minchin, D. idr., 2002). Čeprav je stopnja rasti in številčnost školjke omejena z dejavniki, kot so pretok, razpoložljivost hrane in temperatura, se školjke brez trdne podlage ne morejo naseliti, razširiti ali razmnoževati (McLaughlan, C. in Aldridge, D. C., 2013). V jezerih školjke tvorijo velike populacije, kar pomeni tudi do 120.000 osebkov na kvadratni meter, to pa zaradi aktivne filtracije povzroča večjo prosojnost vode (Minchin, D. idr., 2002). Tako številčnost lahko dosežejo zaradi velike tolerance, saj se na različne življenjske razmere, kot so nihanja vodne gladine, povečana slanost in večja nihanja temperatur, hitro prilagodijo (Remec-Rekar, Š., 2013). Do 19. stoletja je bila školjka prisotna le v Črnem, Kaspijskem in Azovskem morju. Med letoma 1800 in 1900 se je razširjenost školjke po Evropi povečala za dvakrat. Glavne možnosti za širitev so bile plovbe po celinskih vodah, še posebej po odprtju novih plovnih poti med vzhodno in srednjo Evropo v začetku leta 1800 (Birnbaum, C., 2011). Izjemno hitro se je razširila tudi v Severni Ameriki, kjer so jo prvič opazili leta 1988 v jezeru St. Clair (Minchin, D. idr., 2002). V slovenskih vodah je bila trikotničarka prvič opažena v reki Dravi, leta 2010 pa so jo opazili tudi v Blejskem jezeru (Remec-Rekar, Š., 2013). Od leta 2012 potapljači iz Društva za podvodne dejavnosti (DPD) Bled spremljajo njeno širitev po jezeru ter jo poskušajo s fizičnim odstranjevanjem tudi omejiti (DPD Bled). V okolju, ki ga naseljujejo, povzročajo spremembe fizične in biološke strukture. Spremenijo obstoječe življenjske prostore in zagotovijo novo okolje za druge organizme, vplivajo na prehranjevalni splet in razpoložljivost hrane. Prav tako vplivajo na druge procese in stanja v ekosistemih, vključno z mineralizacijo hranil, razpoložljivostjo kisika in stopnjo sedimentacije (Karatayev, Y. A. idr., 2002). Zaradi hitre prilagodljivosti, nevarnosti širitve in njihovega vpliva je treba zagotoviti učinkovit monitoring stanja školjk v Blejskem jezeru in okoliških vodah, v katere se lahko naselijo. S pomočjo tuje in domače znanstvene literature sem se seznanila z invazivno vrsto školjke v jezeru. V analizo školjk, ki so bile nabrane v Blejskem jezeru, smo zajeli velikostno in starostno strukturo populacije školjk ter obseg in gostoto poselitve. Na trinajstih naključno izbranih lokacijah smo s potapljači iz Društva za podvodne dejavnosti Bled (DPD) od januarja do junija 2015 školjke nabirali tedensko. Z vsake lokacije smo podrobno analizirali okoli 250 gramov naključno nabranih školjk, katerim smo izmerili dolžino, širino in višino, namen pa je bilo ugotoviti intenzivnost rasti, glede na posamezne lokacije in starost. Narejena pa je bila tudi biološka analiza vode, s katero sem preverjala prisotnost ličink veliger. Rezultati velikostne in starostne sestave kažejo na stabilnost populacije v jezeru. Iz podatkov o velikosti populacij iz prejšnjih let lahko ocenimo, da do večjega izboljšanja v jezeru ni prišlo.
Ključne besede: Školjka trikotničarka, Blejsko jezero, tujerodna vrsta, vpliv na okolje, velikost populacije, starost osebkov
Objavljeno v RUNG: 30.09.2015; Ogledov: 6457; Prenosov: 289
.pdf Celotno besedilo (2,26 MB)

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