Population fluctuations of the wood lemmingMyopus schisticolor in eastern and western Finland

Abstract

Eskelinen O., Sulkava P. and Sulkava R. 2004. Population fluctuations of the wood lemming Myopus schisticolor in eastern and western Finland. Acta Theriologica 49: 191-202. From 1982 to 2003 we studied fluctuations in populations of the wood lemming Myopus schisticolor (Liljeborg, 1844) in the Heinävesi (eastern Finland) and Keuruu regions (western Finland) by counting field signs and dead animals in standardized field surveys. We compared the population fluctuations of lemmings to those of other voles, owls and small mustelids in these regions. The lemming population in Heinävesi fluctuated regularly in 3-year cycles and in synchrony with the field vole popu-lation. Populations of owls also fluctuated in synchrony with wood lemming and field vole populations. In the Keuruu region, oscillations in the wood lemming population were irregular, and neither lemming and vole populations nor lemming and owl populations were correlated. Although direct mechanistic evidence is lacking, specialist predators such as weasels and owls probably cause the cyclicity in the field vole and wood lemming populations in the Heinävesi area. On the other hand, scarcity of high-quality habitats, unfavourable winter weather conditions and generalist predators may prevent the development of cyclicity in the wood lemming population of Keuruu.

Population dynamics of wood lemming (Myopus schisticolor) in different landscapes of the Northern Pre-Urals

“…This indicates the existence of periodic (cyclic) fluctuations in the populations of this species with a 3-4 years length. In the cyclic population of this species from Eastern Finland have been identified a 3year cycles (Eskelinen et al, 2004). At the same time, according to data of other authors the periods between cycles in the western part of the area can be at least 5 years (Emelyanova & Leonova, 2016).…”

“…It is known that the wood lemming can not be registered by the trap-lines catching method. Therefore, we used, for example, a scoring system consisting of several indirect characteristics to evaluate the abundance of this species in Scandinavia (Eskelinen et al, 2004). The registrations of the wood lemming in the Pechora-Ilych Nature Reserve were carried out by catching ditches and covered different habitats.…”

“…It occurs sporadically on the most of its area and it is a rare species (Henttonen & Hanski, 2000). At the same time, there are areas with a high animal density where wood lemming sometimes dominates in the population of small mammals (Volpert & Shadrina, 2002;Eskelinen et al, 2004;Emelyanova & Leonova, 2016).…”

“…Outbreaks were recorded in different parts of the area, which were repeated extremely irregularly (Nikanorov, 1986;Volpert & Shadrina, 1990;Mysterud, 2016). Infrequently they represented periodic (cyclic) fluctuations (Eskelinen et al, 2004). In the cyclic populations of this species the years with high numbers alternated the years of deep depression.…”

Demography of fluctuating prairie vole populations: comparison of demographic variables among phases of fluctuations

“…These observations agree with other studies showing that predation plays a major role in population fluctuations of arvicoline and other muroid rodents, whether fluctuations are erratic or annual (Hörnfeldt et al 2005) as well as representing multi-annual cycles (Ekerholm et al 2004, 2005. Others have concluded, however, that effects of generalist predators may either dampen population fluctu-ations (Reif et al 2004) or may contribute to continually low population densities of voles (Eskelinen et al 2004). L. L. Getz et al Appendix.…”