Effect of seed crop of trees on the abundance and body parameters of granivorous mammals in isolated forest stands of Southern Moravia [Czech Republic]

Effects of heavy seed crop (mainly oak mast) in year 2003 and 2004 (no seed crops) on small mammal communities in three isolated stands of broad leaved lowland forests (area 60–280 ha) with different management were studied in southern Moravia in three sites: (1) close-to-nature not managed floodplain forest – Ulmeto–Fraxinetum carpineum (FF), (2) managed forest – Carpineto-Quercetum acerosum (MF), (3) pheasantry – Ulmeto-Fraxinetum carpineum, Saliceto- Alnetum and Carpineto-Quercetum acerosum, with a considerable number of biotopes including open areas (PH). We presumed the influence of seed production on mammal species, especially granivorous rodents. In the most numerous species (Apodemus flavicollis (Mel.), A. sylvaticus (L.) and Myodes glareolus (Pallas)) the demographic parameters (abundance, sex ratio), body mass, and body length were compared between populations in 2003 and 2004 in each stand. Animals were trapped in snap mousetraps laid out in lines. In 2003 reproduction of both Apodemus sp. Was extended to November in contrast to 2004, when it ceased already in the end of summer. Individual body mass of animals were significantly higher in 2004 vs. 2003 in all three species (A. flavicollis, P = 0.01; A. sylvaticus, P <0.01 and Myodes glareolus, P <0.05) but body length was higher only in case of A. sylvaticus (P <0.01). The forest stands under study in an intensively managed agroecosystem in southern Moravia play an important role as a refuge for small mammals.