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Identifier 000426354
Title Τροφική οικολογία και επιλογή ενδιαιτήματος τροφοληψίας του Νανόμπουγου [Asio otus] σε μεσογειακά αγροσυστήματα [Κρήτη, Ελλάδα]
Alternative Title Feeding ecology and habitat selection of Long-eared owl [Asio otus] in Mediterranean agrosystems [Crete, Greece]
Author Κοντογεώργος, Ιωάννης Α.
Thesis advisor Μυλωνάς, Μωυσής
Reviewer Καρακάσης, Ιωάννης
Ακριώτης, Τριαντάφυλλος
Δημητρακόπουλος, Παναγιώτης
Γκιώκας, Σίνος
Πουλακάκης, Νικόλαος
Καζαντζίδης, Σάββας
Abstract This study consists into two main parts. Τhe first focuses on the food ecology of Long-eared owl (Asio otus) and the second in habitat selection of the species. In the first part we analyzed the diet composition and dietary patterns of the Long-eared Owl (Asio otus) in Mediterranean agrosystems in central Crete (Greece) over the winters of 2009–2015. Overall, 2,819 prey items were recovered from 1,207 pellets, belonging to six taxa of mammals, 22 taxa of birds and four taxa of insects. Small mammals were the most common prey species, accounting for 75.8% by frequency and 79.7% by biomass, followed by birds (23.2% and 20.1%); the latter being rather an island component compared to continental regions. The House Mouse (Mus musculus) was the most important prey species in the owl’s diet (56.3%) ahead of the Wood Mouse (Αpodemus sylvaticus) (9.51%) and the Black Rat (Rattus rattus) (7.9%). The species proved to be a significant rodent predator in olive groves and vineyards during winter months, selecting Wood Mouse and young Black Rat more than expected. In the second part of this study, we analysed the home range size and habitat selection of 11 Longeared Owls inside olive groves in the plain of central Crete using radio tracking data and remote sensing images. Six nominal scale and 11 landscape scale predictors were used for habitat selection analysis, using a maximum entropy approach. Home range size ranged between 337 and 969 ha while a 52% of home range overlap was observed suggesting that Long-eared Owls do not defend hunting territories. At the nominal scale, distance to potential roosts (trees) was the most important contributor to model performance, followed by vegetation heterogeneity. Furthermore, local heterogeneity of greenness was a better predictor than simply greenness at the presence location. At the landscape scale the amount of habitat openness significantly improved model performance. Incorporating landscape heterogeneity improved habitat selection prediction compared to using only discrete land cover classification. Results of our study pinpoint that although Long-eared Owls exhibit a wide range of habitat tolerance, they prefer mixed habitat conditions avoiding particularly open areas or dense olive plantations. The research has implications in the face of new reforms of European Common Agricultural policy which emphasised the importance of landscape structure in preserving biodiversity in agricultural areas of Europe.
Language Greek
Issue date 2019-11-29
Collection   Faculty/Department--Faculty of Sciences and Engineering--Department of Biology--Doctoral theses
  Type of Work--Doctoral theses
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