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Local warming about 1,3°C in alpine meadow has no effect on root vole (Microtus oeconomus L.) population during winter

Sun P., Zhao X., Klein J. A., Wei W.

Polish Journal of Ecology

2005

Vol. 53, nr 1

123-127

The influence of air and soil warming on root vole (Microtus oeconomicus L.) population was studied in winter period in top open chambers (OTC) (0,8-1,8 m2) warmed byy conical fiberglass material and situated in alpine meadow (33250 m) at Quinghai-Tibet Plateau, China. The OTCs were distributed on an area of 30x30 m of experimental warming site; another site of the same area was a control one. The root vole population was investigated on two pairs of sites in "low-grazing" (by sheep) parts of the meadow; mark-recapture method was used. The winter-season averaged air and soil temperature inside of the chambers were 1.3°C higher than the temperature outside the chambers. The warming in the chambers had no statistically significant effect on root vole numbers, on average body mass of individual, and on average body mass of males and females. In conclusion, as small as 1.33°C warming of soil and air introduced locally and on small (several m2) scale, in the alpine meadow habitat in winter period, has possibly no effect on root vole numbers and biomass.

The Bank vole population in Crabapple Island

Bujalska G.

Polish Journal of Ecology

2000

Vol. 48, Suppl.

97-106

The results of studies on demography of an island population of Clethrionomys glareolus are presented. Population numbers and structure were estimated 5 times a year in 1966-1999. Two patterns of seasonal changes in population size were found: either continuous, slow increase from April (beginning of the breding season) to October, with maximum density below 50 individuals per hectare, or rapid increase resulting in a July/September peak with maximum density up to 153 individuals per ha. The highest variations in number occurred in April (Whittaker's CF=2.05) and decreased with advancement of the breeding season: in September CF=1.49. The mechanism accounting for the decrease was territoriality of mature females. Fluctuating July population numbers revealed cyclic changes, namely a 3,8-year as well as a 9,4-year cycle. It is postulated that social relations between neighboring individuals rather than mean population density affect changes in population numbers.