Vrstna sestava in časovna aktivnost potencialnih plenilcev navadnega polha na vhodih v polšine na Dinaridih

Demić, Lara (author), Jerina, Klemen (mentor)

Zaradi izredno visokih populacijskih gostot in posledično velike biomase je navadni polh pomemben vmesni člen v prehranskem spletu. Plenijo ga številne živalske vrste od plazilcev, sesalcev do ptic ekstremno različnih velikosti npr. od male podlasice do rjavega medveda. Za njegovo plenjenje so za mnoge vrste zlasti zanimivi vhodi v polšine, skozi katere v toplem delu leta polh tudi vsakodnevno prehaja. Z namenom določitve vrstne sestave, pogostnosti in taktik plenilcev polha smo v letih 2021 in 2022 s fotopastmi od maja do novembra nepretrgoma spremljali 10 vhodov v polšine na območju Rakitne. V obeh letih skupaj smo zaznali 24 vrst živali, med katerimi smo jih 6 (kuna, podlasica, lisica, divja in domača mačka ter jazbec) na podlagi literature in vedenja uvrstili v skupino »plenilci polhov«, preostanek (z izjemo navadnega polha) pa smo uvrstili v skupino »ostale vrste«. To skupino smo v analizah smatrali kot kontrolno, saj ni pričakovati, da bi bila neposredno povezana s prehajanjem polhov v polšine. V obeh letih je pojavnost plenilcev in polha pred polšinami tekom toplih mesecev tesno korelirala. Leta 2022 je bil množičen obrod bukve, zaradi katere je gostota polha pričakovano drastično narasla. Ugotovili smo tudi porast pojavnosti plenilcev pred polšinami, vendar v manjši meri od porasta polhov. Pogostnost pojavljanja vrst plenilcev se močno poveča zvečer (ob začetku noči), tik pred viškom izhajanja polhov iz polšin, obratno pa je jutranje povečanje prisotnosti plenilcev manj izrazito kot pri polhu. To nesorazmerje v sinhronizaciji dodatno potrjuje, da plenilci hodijo pred polšine zaradi plenjenja polhov. Pojavnost plenilcev in navadnega polha med spremljanmi polšinami je bila negativna, kar bi lahko bil rezultat bodisi proti-plenilskih strategij polha (npr. raba drugih polšin, redkejše vračanje v polšine med letom), ali pa numeričnega učinka plenilcev na številčnost polha. Za razjasnitev povezave bi bile potrebne dodatne raziskave.

• Language: Slovenian
• Keywords: navadni polh, Glis glis, polšine, plenilci, kuna, divja mačka, korelacije aktivnosti, cirkadiana aktivnost, sezonska aktivnost
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [L. Demić]
• Year: 2024
• PID: 20.500.12556/RUL-159060
• UDC: 630*14:630*15(043.2)=163.6
• COBISS.SI-ID: 200270851
• Publication date in RUL: 29.06.2024

Secondary language

• Language: English
• Title: Species composition and temporal activity of potential predators of edible dormouse before the entrances of their underground cavern exits in the Dinarides

Abstract

Exceptionally high population densities and consequentially large biomass of the fat dormouse make it an important intermediate link in the food web. It is preyed upon by a wide range of species, from mammals, reptiles, to birds of varying sizes, e.g. from the lesser weasel to the brown bear. The entrances of caverns, through which dormice pass on a daily basis during the warm part of the year, are of particular interest to many species for its predation. In order to determine the species composition, frequency and predation tactics of dormouse predators, 10 cavern entrances in the Rakitna area were monitored continuously with photo-traps from May to November in 2021 and 2022. In both years, we detected a total of 24 species of animals, 6 of which (marten, weasel, fox, wildcat, domestic cat and badger) were classified as 'dormouse predators' based on literature and behaviour, and the remainder (with the exception of the fat dormouse) were classified as 'other species'. This group was considered as a control group in the analyses, as it is not expected to be directly related to the activity of dormice. In both years, the occurrence of predators and of dormice in front of entrances during the warm months was strongly correlated. In 2022, there was a massive beech crop, which was expected to drastically increase the density of dormice. We also found an increase in predators in front of the entrances, but to a lesser extent than the increase in dormice. The frequency of predator species increases sharply in the evening (at the beginning of the night), just before the peak of the dormouse emergence, while the morning increase is less pronounced than in the case of dormice. This disproportion in synchrony further confirms that predators wait in front of the entrances to prey on dormice. The occurrence of predators and the fat dormouse was negative between monitored entrances, which could be the result of either anti-predator strategies of the dormouse (e.g. use of other entrances, less frequent return to the caverns during the year) or a numerical effect of predators on dormouse abundance. Further research would be needed to clarify the link.

• Keywords: fat dormouse, Glis glis, predators, marten, wildcat, activity correlations, circadian activity, seasonal activity