Acta Univ Latv (2006) 710: 93–101

Species diversity, abundance and dynamics of small mammals in the Eastern Latvia

Abstract

The paper presents the results of small mammal monitoring carried out in Eastern Latvia in the period from 1991 to 2005. Rodents and shrews were snap-trapped in early summer and autumn using the method of trap-line census. During the investigation, 12 small mammal species were found. In open type habitats Microtus arvalis prevailed with Apodemus agrarius and Sorex araneus subdominating. In forest habitats Clethrionomys glareolus, Apodemus flavicollis and Sorex araneus were more common. The average abundance and species diversity was low in the studied grassland habitats (17.1 ± 2.2 individuals per 100 trap-days; Shannon index H = 1.084; Simpson index c = 0.471). In forest habitats the average small mammal abundance was 10.5 ± 1.4 ind. per 100 trap-days and species diversity H = 1.153; c = 0.407. No cyclicity of small mammal population dynamics and no temporal synchrony among coexisting species were found, although fluctuations of small mammal density were observed in the area in different years. Nevertheless, small mammal populations exhibited spatial synchrony among the fluctuations of density in the sample areas in distances of 10 to 25 km.