Mass occurrence of Apodemus agrarius (Pallas, 1771) and variations in the number of associated Muridae

Abstract

Mass Occurrence oi Apodemus agrarius (Pallas, 1771) and Variations in the Number of Associated Muridae Masowy pojaw Apodemus agrarius (Pallas, 1771) na tle dynamiki liczebności innych myszowatych In 1959 there was an increase in the numbers of Apodemus agrarius Pall, greater than there had been for many years, and it seem ed to us that a description of this gradation would serve a useful purpose, the more so as Polish literature on mass appearances is scanty (K u n t z e, 1937; Simm & Skuratowicz, 1950; Skuratowicz, 1957) and does not deal w ith forest areas. R esearch work on forest rodents in the Kampinos Forest has been carried on by the Field Station of the Institute of Ecology, Polish Academy of Sciences, at Dziekanów Leśny, since 1955. We have made use, in the present paper, of observations conducted on three study areas I, V and VIII (Fig. 1) not w idely separated from each other, situated in sections 28 and 29 of the Warsaw Woods Administration District in the Kampinos National Park1). As far as habitat conditions w ere concerned, the study areas w ere sim ilar to each other, in particular areas I and V. They are covered by forest stands of the Pineto-Quercetum association, changing over on tw o of the fringes to Cariceto elongate-Alnetum. This latter association was more extensively represented in area VIII. Three species of rodent occur in considerable numbers in the study areas: Clethrionomys glareolus (S c h r e b e r, 1730) Apodemus agrarius (Pallas, 1771) and A. flavicollis (Melchior, 1874).Other species occur as single spe­ cimens only, and we shall not discuss them.