Razlike v rabi krmišč rjavega medveda (Ursus arctos) med spolnimi in starostnimi kategorijami osebkov

• Main Author: Dolšak, Klemen
• Other Authors: Jerina, Klemen
• Format: Bachelor Thesis
• Language: Slovenian
• Published: K. Dolšak 2020
• Subjects: rjavi medved; Ursus arctos; krmišča; znotrajvrstni odnosi; habituacija; Kočevje; brown bear; feeding sites; intraspecific relations; habituation; info:eu-repo/classification/udc/630*15:630*14(497.4Kočevje)(043.2)=163.6; Lone
• Online Access: https://repozitorij.uni-lj.si/IzpisGradiva.php?id=115077; https://repozitorij.uni-lj.si/Dokument.php?id=127622&dn=; https://plus.si.cobiss.net/opac7/bib/4072614?lang=sl

V zgodovini se je odnos do rjavega medveda (Ursus arctos) močno spreminjal, s tem pa tudi pristopi k upravljanju z vrsto. Pomemben del upravljanja z medvedom v mnogih državah je tudi krmljenje medvedov na krmiščih. Mnenja o pravilnosti krmljenja kot varstveno % gojitvenega ukrepa, so v svetu različna, kar je deloma posledica slabe raziskanosti učinkov krmljenja in kako medvedi uporabljajo krmišča. To velja tudi za časovne razlike med kategorijami medvedov in interakcije med medvedi ob obiskovanju krmišč. S pričujočo nalogo želimo testirati domnevo, da medvedi zaradi različnih bioloških dejavnikov vrste (parjenje, hiperfagija) in vplivov človeka, tekom leta krmišča obiskujejo z različno frekvenco in se na njih razporejajo različno glede na starost ter spol. Proučili smo tudi neposredne znotrajvrstne interakcij, do katerih prihaja med medvedi na krmiščih. Podatke o obiskih krmišč smo zbirali s pomočjo avtomatskih video kamer. Namestili smo jih na 5 krmiščih za medveda na Kočevskem, znotraj osrednjega območja rjavega medveda v Sloveniji. Na podlagi analize pridobljenih video posnetkov medvedov, smo te razvrstili glede na starostni in reproduktivni status. Ugotovili smo, da je pogostost obiskov krmišč v povprečju najvišja v septembru (pribl. 10 medvedov na dan), kar potrjuje hipotezo o intenzivnejšem prehranjevanju na krmiščih v času hiperfagij v jesenskem času. Ugotovili smo, da medvedi posameznih kategorij krmišč v času ne obiskujejo naključno, ampak v določenem vrstnem redu. Najprej so na krmišča prihajale medvedke z enoletnimi mladiči, nato enoletniki, sledile so samice z letošnjimi mladiči, nevodeče samice in mlajši samci, najkasneje v noči, pa so na krmišča prihajali odrasli samci. Opažen vzorec nakazuje na izogibanje človeku in dominantnim medvedom. Največ znotrajvrstnih interakcij smo opazili med kategorijo nevodečih samic in mlajših samcev. Medtem ko so se mlajši medvedi večinoma tolerirali, smo nasprotno pri odraslih medvedih opazili netoleranco do prisotnosti drugih medvedov na krmišču in agresivno preganjanje. Pridobljene ugotovitve bodo dodatno osvetlile področja ekologije in sociobiologije rjavega medveda v srednjeevropskem prostoru. Podatki bodo tudi dopolnili potrebna znanja za upravljanje ter izboljšale natančnost obstoječe metode monitoringa rjavega medveda s štetji na krmiščih. Human attitudes towards the brown bear (Ursus arctos) changed considerably throughout history and these changes reflected also in different approaches used in management of this species. One of the important measures used in bear management in many European countries is supplemental feeding of bears. Opinions about appropriateness of this controversial measure vary greatly among researchers across the world. These inconsistencies are partly connected with the lack of good understanding about the effects of supplemental feeding and bears% use of the feeding sites. This includes temporal segregation of bears of different age and reproductive categories in the use of feeding sites and interactions that occur among the bears at these sites. Here we tested hypotheses about existence of temporal segregation of feeding site use among bears from different categories and of seasonal variation in frequency of bears% use of feeding sites, which could occur due to several biological factors (e.g. breeding, hyperphagia) and anthropogenic influence. In addition, we studied direct intraspecific interactions among bears visiting feeding sites. Data were obtained with the use of automatic night-vision video cameras, which we deployed on 5 bear feeding sites in Kočevska region (SE Slovenia) within the brown bear population core area. We analysed all video recording and used them to determine age and reproductive category for each bear detected at the feeding sites. Our results indicated that bears did not visit feeding sites randomly, but in certain patterns. The first to come to the feeding sites in the evening were females with yearlings, they were followed by lone yearlings, females with cubs, lone females and young males, and the latest during the night arrived mature males. Observed pattern suggests category-specific avoidance of encounters with humans and dominant bears. We noted the highest frequency of intraspecific interactions among the category of lone females and young males. While the younger bears generally tolerated other bears, we noted low tolerance of conspecifics among the adult bears, which also frequently engaged in aggressive chasing of other bears. Results presented here will help towards further understanding of ecology and sociobiology of brown bears in Central Europe. New data also management implications and could be used to improve accuracy of bear monitoring conducted through systematic counting at feeding sites.