DO SHREWS HAVE AN IMPACT ON SOIL INVERTEBRATES IN EURASIAN FORESTS

Abundance and food consumption of shrews in the European part of the s outhern taiga (Valdai district, Russia) were investigated. Average pop ulation densities of these animals were estimated 31/ha in dry boreal spruce forest, 179 in boreal Picea abies - Oxalis acetosella forest, a nd 224-258 in rich spruce forest. Food consumption in those habitats w as estimated at 25 kg/ha, 152 kg/ha, and 212-244 kg/ha per year, respe ctively. These data are similar to those for western Siberian taiga (1 32-264 kg/ha), mixed forest in the Russian Far-East (177-351 kg/ha), a nd larch forests in north-east Siberia (265-330 kg/ha). These figures also correspond with the biomass of soil invertebrates in the above ec osystems. This provides evidence that shrews have a significant impact on litter decay processes. In particular, shrews diminish the populat ion density of soil invertebrates thus increasing their productivity. Such a response to harvesting is well-known for many populations, from microorganisms to ungulates. Red-toothed shrews do nor significantly change the density of soil invertebrates during summer periods, but th ey probably accelerate decomposition of forest litter and organic matt er in the upper soil layers.