1. The Ural Owl, Strix uralensis macroura, in Slovenia : an overview of current knowledge on species ecologyAl Vrezec, Tomaž Mihelič, 2012, original scientific article Abstract: In Slovenia the Ural Owl, Strix uralensis macroura, is on the north-western limit of its distribution with an estimated population size of 400-700 breeding pairs. The densities of territories range between 0.9 to 13.4 territories per 10 km2, and the highest densities are reached in montane forests of the southern Dinaric region. In the forests with dominant deciduous trees, e.g. Fagus sylvatica and Quercus robur, the breeding densities are significantly higher than in the forests with a higher proportion of coniferous trees, e.g. Picea abies. The species does not select specific altitude and throughout Slovenia it occurs between 150 and 1600 m a.s.l. Most natural nests were found in tree holes or semi-holes (56%) and on the tree stumps (20%). Breeding begins between 15 March to 21 June with median clutch sizes of 3.0 eggs per nest. In the brood there are 2 young and 1.5 young are fledged in median. At present 75% of nests produce at least one young. Voles and Mice are the most frequent prey in the diet, but the Fat Dormouse, Glis glis, seems to have very important role in the post-breeding period. As a top predator, the Ural Owl influences also the distribution of other owl species in the guild through direct predation or competitive exclusion. However, it could have also a positive indirect effect on smaller species, e.g. Tengmalm’s Owl, Aegolius funereus, which are tolerated within Ural Owl territories, and are able to extend their distribution due to exclusion from certain areas of the Tawny Owl, Strix aluco, by the Ural Owl.
Keywords: distribution, breeding density, habitat, breeding biology, interactions, Slovenia
Published in DiRROS: 05.08.2024; Views: 139; Downloads: 115
 Full text (309,04 KB)
This document has many files! More... |
2. |
3. Habitatne značilnosti rastišč divjega petelina (Tetrao urogallus L.) na Uršlji goriŽiga Repotočnik, Klemen Jerina, Tomaž Mihelič, 2021, original scientific article Abstract: V Sloveniji je bilo opravljenih le nekaj raziskav habitata rastišč divjega petelina. Taka znanja so pomembna pri določitvi in izvajanju ukrepov za ohranitev oziroma povečanje številčnosti vrste. Namen dela je bil ugotoviti sedanjo aktivnost dvajsetih znanih rastišč divjega petelina na Uršlji gori z bližnjo okolico v primerjavi s prejšnjima popisoma (Adamič, 1986; Čas, 2000) in evidentirati potencialna nova. Prav tako smo želeli ugotoviti, ali so med aktivnimi in opuščenimi rastišči divjega petelina razlike v habitatnih danostih. Popise aktivnosti rastišč smo izvajali po metodi poslušanja pojočih samcev zgodaj zjutraj in beleženja znakov prisotnosti v času rastitve od 1.4. do 20.5. v letih 2019 in 2020. Habitatne značilnosti rastišč smo popisali na treh aktivnih rastiščih in treh opuščenih. Na podlagi dobljenih rezultatov smo ugotovili, da se je število aktivnih rastišč v primerjavi z letoma/če gre samo za ti leti, sicer v letih 1986 in 2000 zelo zmanjšalo (aktivnih le 30 % od vseh znanih). Na rastiščih smo v obeh letih skupno popisali približno trikrat manj aktivnih petelinov, tri neaktivne več ter 2,7-krat manj kokoši kot leta 2000. Iz tega sklepamo, da je na proučevanem območju vrsta ogrožena in lahko v naslednjih nekaj desetletjih izgine z območja, če se bo trend številčnosti še naprej manjšal. Delež opuščenih rastišč je bil večji v gozdovih z nižjo nadmorsko višino (pod 1200 m). Evidentirali nismo nobenega novega rastišča, so se pa centri aktivnih rastišč v primerjavi z zadnjim popisom spremenili v prostoru. Ugotovili smo razlike v habitatnih danostih med obema tipoma rastišč. Za aktivna rastišča je bila značilna velika pokritost tal z zeliščno plastjo (85 %, od tega 24 % jagodičja), več mravljišč, redkejši sklep sestoja (40-60 % zastrte površine), večja vidljivost pri tleh ter večji delež starejših iglastih sestojev v primerjavi z opuščenimi. Vidljivost pri tleh in delež drevesnih vrst glede na naše ugotovitve nista bistveno vplivala na aktivnost rastišč.
Keywords: divji petelin, Tetrao urogallus L., Uršlja gora, aktivnost rastišč, habitatne značilnosti rastišč
Published in DiRROS: 26.10.2021; Views: 1350; Downloads: 426
Full text (765,89 KB) |
4. Green space area and type affect bird communities in a South-eastern European cityMaarten De Groot, Katarina Flajšman, Tomaž Mihelič, Urša Vilhar, Primož Simončič, Andrej Verlič, 2021, original scientific article Abstract: Urbanization decreases the species richness and results in the homogenization of bird communities. Bird species are important indicator species for biodiversity and reflect the habitat quality of urban forests and other green spaces. In this study we investigated the key drivers that influence bird communities in urban forests and green spaces in the Southeastern European city of Ljubljana, Slovenia. We were interested in how the number of species, species dissimilarity and indicator species are affected by the type of green space (urban forest vs park), area of green space and type of urbanization (urban vs peri-urban areas). We sampled birds twice in 2012 in 39 standardized point counts across Ljubljana. We found that the abundance was influenced by the area of the green space. Species dissimilarity and species turnover are affected by the area and type of green space. Interestingly, the analysis showed that the species composition of peri-urban areas was similar to that of urban areas. Indicator species were found for all environmental variables. On the basis of the results, we suggest the strategy that would increase the diversity of birds and increase the stability of their populations in urban areas. Urban planners should encourage 1) both forests and parks since they harbour different species of birds, 2) larger green spaces since larger areas have species that are more typical of larger areas and 3) a mosaic of a larger number of smaller forest remnants combined with larger forest complex serving as source areas.
Keywords: urban forest, bird species composition, forest remnant, urbanization, peri-urban forest, bird monitoring, species richness
Published in DiRROS: 14.06.2021; Views: 1486; Downloads: 761
Full text (842,93 KB)
This document has many files! More... |
5. Vpliv nekaterih ekoloških dejavnikov na pojavljanje gozdnega jereba Bonasa bonasia v BohinjuBarbara Mihelič, Tomaž Mihelič, 2004, original scientific article Abstract: Avtorja članka sta raziskovala vpliv nekaterih ekoloških dejavnikov na pojavljanje gozdnega jereba na osmih lokacijah v Bohinju.Na 143 popisnih točkah sta ugotovila 25 teritorialnih samcev. Poleg tega sta na podlagi naključnih opazovanj zbrala tudi 79 različnih lokacij pojavljanja vrste v Bohinju. Gozdni jerebi so naseljevali višje nadmorske višine. Osrednji del populacije je bil ugotovljen med 1280 in 1490 m n.m. Primerjava naključno in sistematično zbranih podatkov ni pokazala razlik. Delež listavcev v gozdu na pojavljanje gozdnega jereba ni imel vpliva. Večina gozdnih jerebov je bila zabeležena na ploskvah z večjim deležem iglavcev, vendar se te ploskve niso razlikovale od drugih popisnih ploskev. Delež grmovne in zeliščne plasti ter delež negozdnih površin in jas so imeli pomemben vpliv na pojavljanje gozdnegajereba. Gozdni jerebi so bili prisotni na ploskvah z večjo pokrovnostjo tako grmovne kot zeliščne plasti, kakor tudi na ploskvah z večjimdeležem negozdnih površin. Glavni razlog za pojavljanje negozdnih površin v habitatu gozdnega jereba je pašništvo. Pašništvo v obliki planin ugodno vpliva na številčnost gozdnega jereba, saj spodbuja tri pomembne komponente njegovega habitata (zvečevanje deleža jas ter deleža pokrovnosti v grmovni in zeliščni plasti).
Keywords: gozdni jereb, ekološki dejavniki, paša
Published in DiRROS: 12.07.2017; Views: 4468; Downloads: 1901
Full text (725,10 KB) |
