Ábrahám Levente: Biomonitoring a Dráva folyó magyarországi szakasza mentén 2000-2004 - Natura Somogyiensis 7. (Kaposvár, 2005)

Horváth, Győző, Molnár D., Németh Tamás - Csete Sándor: Landscape ecological analysis of barn owl pellet data from the Drava lowlands, Hungary - A Dráva menti gyöngybagoly köpetekből nyert adatok tájökológiai elemzése

HORVÁTH ET AL.: ECOLOGICAL ANALYSIS OF BARN OWL PELLET DATA 183 Table 3: Homogeneity G-test of cumulated pellet samples in the various Drava reaches Prey taxa Pi (total reach) Pi (total reach) G-values Upper reach Middle reach M. arvalis 46.81 Middle reach 29.58 Lower reach 3.92* S. araneus 19.88 M. arvalis 29.58 4.27 55.63 10.94*** 8.09** ***:p< 0.001; ** :p<0M,*:p<0.05 middle sections were significantly different in one, the lower and middle in two, and the lower and upper in three patch types (Table 2). When food composition was analysed, there were less clear differences than expected between the three river sections. However, significant differences i.e. inhomogeneity occurred in the ratios of the common vole, the most preferred prey animal of the barn owl. This may be due to different small mammal availabilities related with patch composition differences in the various Drava sections. Another significant difference was found in the common shrew, a protected insectivorous small mammal of indicator significance, playing an important role in rating areas with different landscape patterns (Table 3). When data from nesting localities of one of the Drava sections were compared with data for the entire length, more significant results were obtained both in patch composition and in small mammal distributions of their corresponding habitat patches. In patch composition analysis only those patch types were emphasized among significant ones that were habitats of significantly different prey taxa in that sample. This revealed correlation between the most frequent Table 4: Homogeneity G-test of pellet samples and patch compositions in the various nesting localities and in complete Drava reaches Reaches Nesting sites Prey taxa / patch types pi (total reach) pi (given nest site) G-values Upper reach Zákány M. arvalis 46.81 21.02 10.06** crop field 14.85 1.76 1 j ^^*** Gyékényes C. glareolus 3.77 0.00 5.23* Apodemus spp. 12.65 3.39 5.69* dry closed deciduous 39.08 0.00 54.18*** forest wet closed deciduous 13.63 0.00 18.89*** forest Middle reach Berzence S. araneus 19.88 0.86 21.58*** C. glareolus 3.47 0.00 4.81* dry closed deciduous 46.87 0.00 64.98*** forest M. arvalis 29.58 58.62 974** crop field 13.31 63.73 35.89*** mixed agricultural 2.23 11.55 6.91** areas Heresznye Apodemus spp. 9.10 0.00 12.62*** dry closed deciduous 46.87 0.00 64.98*** forest Lower reach Vajszló S. araneus 4.27 13.95 5.41* dry closed deciduous 19.63 49.29 13 19*** forest forest plantation 11.51 24.11 4.56* ***:p< 0.001; ** :p<0M, *:p <0.05