Ishrana zimujućih malih ušara Asio otus u Županjskoj Posavini

The study presents the diet of the Long-eared Owl at wintering roosts in rural areas of Strošinci, Drenovci, Bošnjaci and Županja in Županjska Posavina. The total of 1,073 pellets were collected during the winter of 2014/2015; they contained remains of 2,473 specimens belonging to 13 species of small mammals and two bird species. The average number of prey per pellet was 2.36. The majority of small mammal species belonged to the Arvicolinae and Murinae subfamilies, with Common Vole Microtus arvalis being the most dominant species represented in the diet (76.1%). The food niche of the Long-eared Owl measured by standardised Levin’s index of niche breadth was the widest (0.07) in Strošinci, and the narrowest (0.02) in Bošnjaci. The Shannon–Wiener’s measure of diet niche breadth varied between 1.12 (Strošinci) and 0.58 (Bošnjaci). According to the Bray–Curtis index, the highest percentage overlap of prey composition (86.56%) was between Županja and Bošnjaci. Županjska Posavina was hit with catastrophic floods during the summer of 2014. A comparison among flooded and not flooded areas showed no statistically significant difference in the prey composition of the wintering Long-eared Owl in studied areas.U radu su predstavljeni rezultati istraživanja ishrane male ušare na zimovalištima u selima Strošinci, Drenovci i Bošnjaci i gradu Županji u Županjskoj Posavini. Tijekom zime 2014/2015. godine prikupljene su 1073 gvalice koje su sadržavale 2473 osteološka ostatka 13 vrsta sisavaca i dvije vrste ptica. Prosječan broj plijena po gvalici iznosio je 2.36. Većina vrsta sitnih sisavaca pripadala je potporodicama Arvicolinae i Murinae. Poljska voluharica Microtus arvalis, je bila najzastupljenija u ishrani male ušare s 76.1 %. Ekološka niša ishrane male ušare prema standardiziranoj Levinovoj mjeri najšira je u Strošincima (0.07) a najuža u Bošnjacima (0.02). Prema Shannon–Wienerovoj mjeri, također je najšira u Strošincima (1.12), a najuža u Bošnjacima (0.58). Najveće postotno preklapanje širine ekološke niše prema Bray – Curtisovom indeksu je je kod malih ušara koje zimuju u Bošnjacima i Županji (86.56%). Nije bilo statistički značajne razlike u sastavu plijena zimujućih malih ušara na istraživanim lokalitetima obzirom na poplavljenost staništa tijekom ljeta i jeseni 2014. godine