Pregled rodnosti populacij rjavih medvedov (Ursus arctos L.) v Evropi.

• Main Author: Capuder, Luka
• Other Authors: Jerina, Klemen
• Format: Bachelor Thesis
• Language: Slovenian
• Published: L. Capuder 2020
• Subjects: rjavi medved; relativna rodnost; Ursus arctos; brown bear; relative natality; info:eu-repo/classification/udc/630*14Ursus arctus+630*15(4)(043.2)=163.6
• Online Access: https://repozitorij.uni-lj.si/IzpisGradiva.php?id=120575; https://repozitorij.uni-lj.si/Dokument.php?id=135387&dn=; https://plus.si.cobiss.net/opac7/bib/32171523?lang=sl

Raziskovali smo, kakšne so vrednosti relativne rodnosti rjavega medveda (Ursus arctos L.) v Evropi in kako se razlikujejo glede na geografsko širino in lokalne gostote medvedov ter ali so prisotne razlike v rodnostih med območji, kjer se krmljenje oziroma odstrel izvaja. Poleg tega smo želeli poiskati povezave med rodnostmi in drugimi reprodukcijskimi parametri. Podatke smo pridobili z zbiranjem in pregledom strokovne literature. Kjer je bilo to možno, smo relativno rodnost povzeli, drugače pa smo jo izračunali na podlagi podatkov pridobljenih s pomočjo ankete, ki smo jo poslali strokovnjakom s področja rjavih medvedov (LCIE). V raziskavi nismo odkrili nobenih vplivov obravnavanih spremenljivk na relativno rodnost, smo pa dokumentirali, da so ocene rodnosti dokaj izenačene in se najverjetneje nahajajo na intervalu od 20 % do 25 %. Iz vrednosti pa izstopa območje Apeninov, kjer smo zabeležili najnižje rodnosti, ki so najverjetneje posledica majhne številčnosti medvedov v populaciji (Aleejev efekt). Rezultati lahko variirajo zaradi uporabe različnih metod za določitev rodnosti in problema primerljivosti podatkov med različnimi državami. Prav tako so nekatere ocene rodnosti lahko nezanesljive (podcenjene). In the thesis, we calculated the value of relative natality of brown bear populations (Ursus arctos L.) in Europe. We studied the effect of geographical latitude and local densities on relative natality, and we were also interested in differences between natality in areas where artificial feeding is allowed and where it is not. The same goes for the effect of harvesting. Furthermore, we sought connections between natality and reproductive parameters. We gathered information by examining literature from experts. Where it was possible, we summarized the value, otherwise we calculated it using data from a survey we sent to brown bear experts (LCIE). In our research, we did not find any connections between relative natality and our research variables. However, we did document that estimated values of relative natality are most likely between 20 % and 25 %. A result that stands out comes from the Apennine area, where we found the lowest estimated value of natality, which could be due to small numbers of individuals in the brown bear population (the Alee effect). The results may vary because we used different methods to estimate relative natality and the data that we used was not always comparable between countries. Furthermore, some values of natality could be unreliable (underestimated).