Search

Knowledge about breeding biology is often incomplete in species with complex reproductive strategies. The brown bear Ursus arctos is a polygamous seasonal breeder inhabiting a wide variety of habitats and environmental conditions. We compiled information about brown bear breeding season dates from 36 study areas across their distribution range in the Palearctic and Nearctic regions and investigated how their breeding phenology relates to geographical factors (latitude, photoperiod, altitude and region). Brown bear matings were observed for 8 months, from April to November, with a peak in May%July. We found a 59-day difference in the onset of bear breeding season among study areas, with an average 2.3 days delay for each degree of latitude northwards. The onset of the breeding season showed a strong relationship with photoperiod and latitude, but not with region (i.e. Palearctic vs Nearctic) and altitude. First observa- tions of bear mating occurred earlier in areas at lower latitudes. Photoperiod ranged between 14 and 18 hours at the beginning of the season for most of the study areas. The duration of the breeding season ranged from 25 to 138 days among study areas. None of the investigated factors was related to the length of the breeding season. Our results support the relevance of photoperiod to the onset of breeding, as found in other ursids, but not a shorter breeding season at higher latitudes, a pattern reported in other mammals. Our findings suggest a marked seasonality of bear reproductive behaviour, but also certain level of plasticity. Systematic field observations of breeding behaviour are needed to increase our knowledge on the factors determining mating behaviour in species with complex systems and how these species may adapt to climate change.

Vreme i klima neke oblasti odraz su na prvom mestu osobenosti opšte cirkulacije atmosfere. Promene u atmosferskoj cirkulaciji su presudne zato što su one često praćene promenama u površinskim meteorološkim promenljivama. Da bi se lakše proučavala veza između atmosferske cirkulacije i lokalnih vremenskih uslova, vrši se klasifikacija sinoptičkih sistema, tj. određuju se tipovi cirkulacije. Zato je glavni cilj ove disertacije da se na objektivan način identifikuju i opišu tipovi cirkulacije koji karakterišu vremenska stanja iznad Srbije. Proučavanje tipova cirkulacije je aktuelna tema, koja se stalno unapređuje i dopunjuje. Metod Jekinson-a i Collison-a je objektivna verzija Lamb-ove klasifikacije atmosferske cirkulacije, gde je dnevna cirkulacija okarakterisana upotrebom indeksa povezanih sa pravcem, jačinom i vrtložnošću strujanja. Ovaj metod je bio primenjen iznad Srbije za period od 1961. do 2010. Dobijeno je dvadesetšest cirkulacionih tipova: osam usmerenih tipova po pravcu − severni (N), severoistočni (NE), istočni (E), jugoistočni (SE), južni (S), jugozapadni (SW), zapadni (W) i severozapadni (NW), zatim dva vrtložna tipa zasnovana na jačini vrtložnosti − ciklonalni (C) i anticiklonalni (A) i šesnaest hibridnih tipova (osam ciklonalnih i osam anticiklonalnih za svaki pravac). Sinoptičke karakteristike dobijenih tipova su razmatrane za sve četiri sezone. Svaki cirkulacioni tip ima poseban sinoptički obrazac koji daje očekivan tip i smer strujanja iznad posmatrane oblasti. Analizirani su i trendovi i relativne učestalosti cirkulacionih tipova. Mana metoda Jekinson–a i Collison–a je što nema podataka na višim nivoima. Ovaj nedostatak je rešen u disertaciji tako što su analizirane anomalije geopotencijalne visine na 500 hPa. Utvrđeno je da je anticiklonalni (A) cirkulacioni tip najučestaliji u jesen (23,87%), zatim zimi (18,93%) i u leto (18,70%). Sledi severoistočni tip (NE) sa čestinom od 16,65% za vreme letnje sezone. A tip ima pozitivan trend za zimu i proleće i statistički značajan negativan trend za jesen i leto. C tip pokazuje značajno negativan trend samo u proleće... One of the primary dynamic factors shaping weather and climate of an area is the atmospheric circulation. Regional or local changes in meteorological parameters in the mid-latitudes are mainly controlled by the atmospheric circulation. In order to study relationships between atmospheric circulation and local weather conditions, classification of the synoptic systems is conducted, i.e., circulation weather types (WTs) are determined. Therefore, the main goal of this thesis is to objectively determine and explain the circulation weather types over Serbia. Studying of circulation types is a current topic that is constantly improved and updated. The method of Jenkinson and Collison is an objective version of the Lamb’s classification of atmospheric circulation, in which daily circulation is characterized using a set of indices associated with the direction, strength and vorticity of the flow. This method has been applied to the atmosphere over Serbia for the time period 1961- 2010, resulting in 26 WTs: eight pure directional types - northerly (N), northeasterly (NE), easterly (E), southeasterly (SE), southerly (S), southwesterly (SW), westerly (W) and northwesterly (NW), two pure types based on the severity of the vorticity - cyclonic (C) and anticyclonic (A), and sixteen hybrid types (eight cyclonic and eight anticyclonic for each direction). Synoptic characteristics of circulation types against all four seasonal times are considered. Each of the circulation types has a distinct underlying synoptic pattern that produces the expected type and direction of flow over the study area. Trends and relative frequencies of the circulation types are analyzed. A shortcoming of this method is the lack of data on other higher levels. In thesis, this deficiency has been solved by the vertical structure of the atmosphere that was employed to analyze the anomalies of the geopotential height at the 500 hPa. It has been found that the anticyclonic type (A), is the most common type of circulation in autumn with a frequency of 23.87%, then winter (18.93%) and summer (18.70%), followed by the northeasterly type (NE) with a frequency of 16.65% during the summer season. The A type has a positive trend for winter and spring, and significant negative trend for autumn and summer. The C type shows a significantly negative trend only in spring...

Detaljni podaci o dinamici populacije vrste Gammarus balcanicus na izvoru rijeke Žrnovnice ne postoje, unatoč njenoj širokoj rasprostranjenosti i velikoj važnosti u kruženju tvari u potocima i rijekama. U skladu s tim, cilj ovog istraživanja bio je istražiti ekologiju i neke aspekte reproduktivne biologije ove vrste. Istraživanje je provedeno tijekom četiri sezone od zime 2013. do jeseni 2014. godine u eukrenalu izvora rijeke Žrnovnice. Standardni fizikalno-kemijski parametri vode mjereni su mjesečno od prosinca 2013. do prosinca 2015. godine. Replikativni kvantitativni uzorci (modificirani AQEM protokol) prikupljeni su pomoću Surber mreže jednom u sezoni. U laboratoriju su jedinke klasificirane prema ontogeniji, reproduktivnom statusu i spolu tijekom svake sezone na različitim mikrostaništima. Cilj rada bio je istražiti ključne abiotičke ekološke čimbenike tijekom godišnjih doba, dinamiku populacije istraživane vrste i različite aspekte životnog ciklusa. Nije bilo značajne sezonske varijacije u fizikalno-kemijskim parametrima, a uvjeti koji vladaju u eukrenalu ukazuju na oscilacije temperature vode manje od 1 °C. Vrsta Gammarus balcanicus na izvoru rijeke Žrnovnice najviše obitava na fitalu na kojem je dominantna s obzirom na gustoću jedinki i veličinu tijela. Mužjaci su obično brojniji i veći od ženki, a ovigerne ženke i juvenilne jedinke pojavljuju se u svim godišnjim dobima. Ženke pokazuju veću brojnost u toplijim mjesecima. Sezona razmnožavanja vrste G. balcanicus je tijekom cijele godine zbog stalne temperature vode na izvoru rijeke, a rezultat je i utjecaja mediteranske klime te prosječno više srednje godišnje temperature zraka. So far there are no detailed data on the population dynamic of Gammarus balcanicus in the Žrnovnica spring despite its wide range and great importance in matter circulation in streams and rivers. In concordance with that, the aim of this study was to investigate the ecology and some aspects of reproductive biology of the species. Field studies were carried out across the four season from winter 2013 to autumn 2014 at eucrenal of the Žrnovnica spring. Standard physical and chemical parameters of water were measured monthly from December 2013 to December 2015. Quantitative replicate samples (modified AQEM protocol) were collected using a Surber net once per season. In the laboratory, the specimens were classified according to their ontogeny, reproduction status and sex during the each season on various microhabitats. The aim was to examine the range of abiotic environmental conditions during the seasons, population dynamics of the species, and some aspects of life history traits. There were no significant seasonal variations in physico-chemical parameters and temperature which confirmed eucrenal conditions with less than 1 °C of fluctuations. Species Gammarus balcanicus at the spring of the River Žrnovnica prefer fital on which they are prevalent according to their number and size. Males are generally more numerous and larger than females, and ovigerous females and juveniles occur in all seasons. Females show a greater abundance in the warmer months. The breeding period of G. balcanicus is ongoing through the whole year because of constant water temperature at the spring source as well as a result of the influence of Mediterranean climate and higher average annual air temperature.

V poskusu smo primerjali rastne, pitovne in klavne lastnosti prašičev (n=240), ki smo jih razdelili v poletno (POL) in zimsko (ZIM) skupino. V POL skupini je bila povprečna temperatura (T) 26,4 °C, medtem ko je bila v ZIM skupini 20,1 °C in je variirala med 7,0 °C in 32,2 °C. Vsi pujski so bili pripeljani iz farme Pristava pri povprečni starosti 70 dni in 26 kg. V času poskusa smo merili mikroklimatske pogoje v hlevih, beležili dnevno porabo krme (na skupino), spremljali rast in merili debelino hrbtne slanine (DHS) (pri starosti 71, 146 in 180 dni). Prašiči so bili nato pri starosti 181 dni zaklani v klavnici po standardnem postopku. V ZIM skupini smo izmerili višje vrednosti CO2 in nižjo koncentracijo O2 v primerjavi z POL skupino. Prašiči POL skupine so imeli skozi vsa obdobja pitanja slabšo konzumacijo krme v primerjavi z ZIM skupino. Zaradi slabše konzumacije v celotnem obdobju pitanja so imeli prašiči POL skupine nižji dnevni prirast, kar se je odrazilo v nižji živi masi ob zakolu in nižji masi klavnega trupa. Naši rezultati kažejo, da so nizke T in s tem povečana konzumacija vplivali na značilno poslabšanje konverzije (P=0,000) v ZIM skupini. Prav tako pa smo pri prašičih ZIM skupine ob zakolu zaznali višjo maso toplih polovic (MTP) in nižji odstotek mesnatosti (M). In the experiment we compared growth, feeding and slaughtering characteristics of pigs (n=240), which were divided into summer (SUM) and winter (WIN) group. The average Temperature (T) in the SUM group was 26.4 °C. The average T in the WIN group was 20.1 °C and it varied between 7.0 °C and 32.2 °C. All of the pigs had been brought from the pig farm in Pristava at the average age of 70 days and mass of 26 kg. During our experiment we measured the microclimatic conditions in pig stables, the consumption of pig fodder (per group), growth and thickness of fatback (BF) at the age of 71, 146 and 180 days. The pigs were then slaughtered in a slaughterhouse following the standard procedure at the age of 181 days. In comparison with the SUM group, the WIN group had higher values of CO2 and a lower concentration of O2. The consumption of pig fodder in the SUM group was smaller than the consumption in the WIN group. Due to the smaller consumption in the entire period, the pigs from the SUM group had a lower daily growth, which could be seen from lower living mass and lower mass of the carcase when the pigs were slaughtered. The results show that increased consumption due to low T resulted in a lower feed conversion rate (P=0.000) in the WIN group. When the pigs were slaughtered we also established a higher mass of hot carcase weight (HCW) and a lower lean-meat percentage (LM%).

Brojne riblje vrste reda Gadiformes imaju veliki gospodarski značaj u svjetskom ribarstvu. U lovinama pridnene povlačne mreže koće u istočnom dijelu srednjeg Jadrana zabilježeno je šest vrsta ovoga reda. Najbrojnija vrsta je oslić (Merluccius merluccius) ; slijede: ugotica pučinka (Micromesistius poutassou), tabinja bjelica (Phycis blennoides), ugotica (Trisopterus minutus) te ugotica srebrenka (Gadiculus argenteus) i ugorova majka mrkulja (Gaidropsarus mediterraneus) kao jedine dvije vrste koje nemaju nikakav gospodarski značaj. Ulov navedenih vrsta reda Gadiformes je u proljetno-ljetnom razdoblju bio veći od onog u jesensko-zimskom.