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Influence of population density upon rodent production in a deciduous forest
Annales Zoologici Fennici
Vol. 8, No. 1 (1971), pp. 137-144
Published by: Finnish Zoological and Botanical Publishing Board
Stable URL: http://www.jstor.org/stable/23731827
Page Count: 8
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The numbers of small rodents were estimated by sampling in a deciduous forest (Tilio-Carpinetum) in southern Poland during several years. For two consecutive years, representing high and low population densities (44 and 17 animals per ha) of bank voles (Clethrionomys glareolus) and field mice (Apodemus flavicollis), the age of the animals caught was determined, and their life tables were constructed. At the high density the mean life span was 2.2 months for voles and 2.4 months for mice, while at the low density the figures were 2.8 and 3.1 months, respectively. The growth rate of individuals is slower in the year of peak abundance. The body weights of voles and mice born in that year reached averages of 13.2 and 17.8 g, whereas in the normal year the values were 14.5 and 20.6 g. Net production was estimated for the two densities of these rodent populations. The values obtained for voles amounted to 2 874 and 1 121 kcal/ha per year, and for mice to 856 and 535 kcal. At the low density, vole and mouse populations achieved a much better percentage of their potential production. The efficiency of the net production in relation to costs of maintenance was also better at the low density. The turnover of individuals varied greatly in relation to animal numbers; to a smaller extent this was also true of the turnover of biomass.
Annales Zoologici Fennici © 1971 Finnish Zoological and Botanical Publishing Board