Landscape ecological analysis of barn owl pellet data from the Drava lowlands, Hungary

Abstract

Small mammal fauna monitoring in the Drava Lowlands has been done partly by barn owl pellet collecting and analysis. In the present study the correlations between landscape patterns and barn owl food composition (i.e. the indirect representation of small mammal communities) were analysed using an approach how the cummulated data of particular breeding pairs can be interpreted as characteristic for the patch composition of the mosaic landscape considerably larger than the hunting range of barn owls. For landscape ecological analysis CORTNE LANDCOVER 1:50.000 mapping categories were applied, based on which natural or semi-natural areas, differing from each other also in their barn owl hunting qualities, were differentiated. Three larger areas along river Drava were investigated: two in the upper reach monitoring zone (ZákányPorrogszentkirály, and Berzence-Heresznye), and one in the lower Drava reach (Drávaiványi-Szaporca). In the two upper-reach zones the localities differed from the greater scale landscape in less than 30% of the patches, with only 3-5 patches showing significant difference. In the lower reach there was one sampling locality with 6 patches differing from the greater-scale area, although in the entire lower section 33% or less difference was found between patch compositions of the two scales. Based on patch overlap calculations and homogeneity tests it was concluded that small mammal faunal data of the localities can be cumulated and can be evaluated on much larger landscape ecological scales than barn owl hunting ranges.