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Zaradi številčnega upada populacije velikega skovika Otus scops na Goričkem, smo v letih 2012 in 2013 izvedli ekološko raziskavo o domačem okolišu, prehrani in rabi prehranjevalnih habitatov velikega skovika na Goričkem (SV Slovenija). Prehrano smo določili na podlagi posnetkov plena, ki so jih starši prinašali mladičem. Večino plena so predstavljali nevretenčarji (81,4 %), vretenčarji so bili zastopani le z 2,0 %. Med nevretenčarji so se za glavni vir prehrane velikega skovika izkazale kobilice (Orthoptera) (74,4 % ), med katerimi je bila najbolj pogosta drevesna zelenka Tettigonia viridissima z 21,4 %. Da bi ugotovili velikost domačega okoliša in prehranjevale habitate velikega skovika, smo jih spremljali s pomočjo radijske telemetrije, eno samico pa smo opremili z GPS logerjem. Domači okoliši velikih skovikov so merili med 8 in 24 ha, povprečno 15,9 ha. Za skovike so najpomembnejši prehranjevalni habitat predstavljali košeni travniki, sledile so njive, sadovnjaki, kjer pasejo živino, zaraščajoče se površine ter nasad sadnega drevja (črni bezeg). V letu 2012 so za prehranjevalni habitat skoviki večkrat izbirali tudi travnata dvorišča. Upad populacije velikega skovika na Goričkem lahko pripišemo pomanjkanju ustreznega prehranjevalnega habitata, saj izginjajo drevesno – grmovne mejice zaradi komasacij, ekstenzivni travniki se bodisi zaraščajo, bodisi jih kmetje intenzivirajo ali spremenijo v njive. Tekom raziskave smo ugotovili, da veliki skovik potrebuje odprt habitat, ekstenzivno obdelovane travnike, mejice, posamezna večja drevesa, ki mu omogočajo tako prehrano kot mesta za petje, kar omogoča ekstenzivno kmetovanje, bogato z mejicami in posameznimi velikimi drevesi ter mozaično krajino. Glede na pridobljene rezultate in opazovanja tekom naše raziskave priporočamo ohranjanje tradicionalnih sadovnjakov in posameznih večjih dreves (mesta za gnezdenje), zmanjšanje števila košenj, najbolje enkrat na leto (septembra), s puščanjem nekošenih pasov vsaj 10 % površine parcele, širokih 10-20 m, saj delujejo kot refugiji za žuželke, še posebej kobilice. Med dvema refugijema naj bo maksimalna razdalja 30 m. Dodatno priporočamo zmanjšanje uporabe pesticidov ali njihovo popolno ukinitev, saj pesticidi pomembno povečajo stopnjo smrtnosti žuželk. Učinkovit dolgoročni naravovarstevni ukrep bi bil zasaditev mejic in posameznih večjih dreves oziroma zmanjšanje izsekavanja le teh, zmanjšanje vnosa pesticidov, ki negativno vpliva na populacije žuželk ter opustitev komasacij. Ker na Goričkem primanjkuje naravnih dupel, primernih za skovika, predlagamo namestitev ustreznih gnezdilnic (višina vsaj 6 m od tal, primerna vhoda odprtina) v za skovika primeren habitat. Gnezdilnice morajo biti redno vzdrževane, saj lahko v nasprotnem primeru delujejo kot ekološke pasti. Due to steep decline of the Eurasian Scops Owl Otus scops in Natura 2000 site Goričko (NE Slovenia), we conducted an ecological research in 2012 and 2013 on its home range, diet and use of foraging habitats. The diet was determined based on the images of prey brought by parents to their offspring at night, obtained by Reconyx cameras placed at the nestbox entrance. The majority of prey were invertebrates (81,4 % by frequency), only 2,0 % were vertebrates. Among invertebrates, orthopetrans (Orthoptera) were the main source of prey for the Scops Owl (74,4 %), with the great green bush-cricket Tettigonia viridissima prevailing with 21,4 %. VHF (2 males and 1 female) and GPS telemetry (1 female) were used to determine the size of home range and foraging habitats of the Scops Owl. Home range sizes of the Scops Owl ranged from 8 to 24 ha (average 15.9 ha). The most important foraging habitat for the species was mowed meadows, followed by fields, traditional orchards with grazing livestock, overgrown surfaces and plantation of fruit trees (black elder). In 2012, Scops Owls also preferred grassy backyards as their foraging habitat. The decline in population of the Scops Owl in Goričko can be attributed to the lack of suitable foraging habitat, as hedges are disappearing because of land consolidation, while extensive meadows are either becoming overgrown, intensified or transformed into arable fields. During the research, we established that the Scops Owl needs open habitat, extensively cultivated meadows, hedges, traditional orchards, individual larger trees that provide perches as well as places to hoot, which are allowed or even enhanced by extensive farming, creating a highly mosaical landscape. According to the results obtained and observations from the field, we recommend the conservation of traditional orchards, hedges and individual larger trees (nesting areas especially trees with natural cavities), the reduction of the number of cuts on meadows, leaving unmowed strips of at least 10% of the plot, that act as refuge for insects, especially orthopterans. The maximum distance between two neighbouring refuges should be 30 m. Effective long-term nature conservation measures would include planting hedges and individual large trees or stopping them from being cut down, reducing or completely restricting from the use of pesticides which negatively impact the size of insect populations and their diversity, and limiting land consolidation. Due to the lack of natural tree hollows in Goričko that would be appropriate for the Scops Owl, we recommend the installation of nestboxes (placed at least 6 m from the ground, with appropriate entrance opening) into suitable habitat. Nesting boxes must be regularly maintained, as they may otherwise function as ecological traps. |
