Effect of rodents on the primary productivity of alpine meadows in Bieszczady Mountains

Abstract

Abstract The distribution, abundance and density of small rodents was studied in the alpine meadows of the polish Bieszczady mountains (Eastern Carpathians). The energy flow through the population of rodents was estimated in this ecosystem. The alpine meadows ("połonina's") have an autonomous community of small rodents. The voles (Pitymys subterraneus and Microtus agrestis) are dominating, other meadow rodents (Sicista betulina, Apodemus agrarius, Arvicola terrestris) occur only sporadically while the forest rodents (Apodemus flavicollis, Clethrionomys glareolus) may occasionally feed in alpine meadows. The distribution of rodents in the alpine meadows is uneven; in the dwarf shrubs (scrub) they are four times as abundant as in the open meadows. The estimated mean rodent density on grass alpine meadows was 15 per hectare (13 P. subterraneus and 2 M. agrestis). The energy flow through these populations of P. subterraneus and M. agrestis amounts to 61 012 kcal/ha/year. Of this, the cost of maintenance is 60 000 kcal and the net production is only 1000 kcal. The annual food consumption of these rodents is over 76 000 kcal/ha. This corresponds to 20 kg of dry hay which was eaten from every hectare. However, the influence of rodents on the alpine meadows vegetation is negligible, as they are consuming only 1.03% of the annual primary productivity.