Umetne vodne akumulacije za zasneževanje na vzhodu Pohorja (Slovenija): mesta razmnoževanja in ekološke pasti za dvoživke | Artificial Water Accumulations for Snowmaking on Eastern Pohorje (Slovenia): Breeding Sites and Ecological Traps for Amphibians

Slovenian. Umetni vodni habitati so lahko za dvoživke mesta za razmnoževanje kot tudi ekološke pasti. Vodne akumulacije za umetno zasneževanje niso optimalni habitati za dvoživke in o njihovem razmnoževanju v teh vodnih telesih je malo znanega. V raziskavi smo dvoživke vzorčili v dveh akumulacijah za umetno zasneževanje na območju Mariborskega Pohorja. Ena se nahaja ob vznožju Pohorja (312 m nmv) v urbanem okolju, druga pa na pobočju Pohorja (560 m nmv), obdana z gozdom, ki je del Natura 2000 območja Pohorje. V akumulacijah smo skupno potrdili razmnoževanje sedmih vrst dvoživk: velikega pupka (Triturus carnifex), planinskega pupka (Ichthyosaura alpestris), navadnega pupka (Lissotriton vulgaris), hribskega urha (Bombina variegata), navadne krastače (Bufo bufo), sekulje (Rana temporaria) in rosnice (Rana dalmatina). Hribski urh in veliki pupek spadata med kvalifikacijske vrste za Natura 2000 območje Pohorje. V akumulaciji ob vznožju Pohorja, v kateri so bile tudi ribe, razmnoževanje dvoživk ni bilo uspešno. V akumulaciji na pobočju Pohorja, kjer rib ni bilo, sta strma brežina (30–60°) iz nepokrite geomembrane in nizka gladina vode povzročili pogin odraslih hribskih urhov in številnih (> 500) mladostnih osebkov rjavih žab. Upad gladine vode je povzročil tudi propad jajc in zarodkov velikega pupka. Akumulaciji za zasneževanje sta iz več vidikov neprimerni za dvoživke, vendar jih te kljub temu porabljajo za razmnoževanje. Za zmanjšanje poginov dvoživk bi bili potrebni naslednji ukrepi: ohranjanje maksimalnega vodostaja v času razmnoževanja (marec–julij), pokritost geomembrane in zmanjšanje naklona brežine akumulacije, kar bi dvoživkam olajšalo izhod iz akumulacije, odstranitev rib z jesenskim praznjenjem akumulacije in preprečevanje povozov na cestah ob akumulaciji.

English. Artificial water habitats can be breeding sites for amphibians but may also function as ecological traps. Water accumulations for artificial snowmaking are not optimal habitats for amphibians, and little is known about their reproduction in these water bodies. In this study, we sampled amphibians in two accumulations for snowmaking in the Mariborsko Pohorje area. One is located at the foothills of Pohorje (312 m a.s.l.) in an urban environment, and the other on the slopes of Pohorje (560 m a.s.l.), surrounded by forest that is part of the Natura 2000 Pohorje. In total, we confirmed the reproduction of seven amphibian species in these accumulations: Italian Crested Newt (Triturus carnifex), Alpine Newt (Ichthyosaura alpestris), Smooth Newt (Lissotriton vulgaris), Yellow-bellied Toad (Bombina variegata), Common Toad (Bufo bufo), Common Frog (Rana temporaria), and Agile Frog (Rana dalmatina). The Yellow-bellied Toad and the Italian Crested Newt are qualifying species for the Natura 2000 Pohorje site. In the accumulation at the foothill of Pohorje, where fish were present, amphibian reproduction was unsuccessful. In the accumulation on the slope of Pohorje, where there were no fish, the steep banks (30–60°) with uncovered geomembrane and the low water level led to the mortality of adult Yellow-bellied Toads and numerous (>500) juvenile Rana sp. frogs. The drop in water level also resulted in the stranding of eggs and embryos of the Italian Crested Newt. Snowmaking reservoirs are unsuitable for amphibians in several respects, yet they still use them for breeding. To reduce amphibian mortality, the following measures should be implemented: maintaining maximum water levels during the breeding season (March–July), covering the geomembrane and reducing the bank steepness to facilitate amphibian exit, removing fish through autumn reservoir drainage, and preventing roadkill on roads adjacent to the reservoirs.