Fading out of vole and predator cycles?

Abstract

Northern voles and lemmings are famous for their spectacular multiannual population cycles with high amplitudes. Such cyclic vole populations in Scandinavia have shown an unexpected and marked long-term decline in density since the early 1970s, particularly with a marked shift to lower spring densities in the early 1980s. The vole decline, mainly characterized by a strongly decreased rate of change in numbers over winter, is associated with an increased occurrence of mild and wet winters brought about by a recent change in the North Atlantic Oscillation. This has led to a decrease in winter stability and has shortened the period with protective snow cover, the latter considered as an important prerequisite for the occurrence of multiannual, high-amplitude cycles in vole populations. Although the vole decline is predicted to be negative for predators' reproduction and abundance, empirical data showing this are rare. Here we show that the dynamics of a predator-prey system (Tengmalm's owl, Aegolius funereus, and voles), have in recent years gradually changed from 3-4 yr, high-amplitude cycles towards more or less annual fluctuations only.

Experimental demonstration of the antiherbivore effects of silica in grasses: impacts on foliage digestibility and vole growth rates

“…Vole populations, as with many small mammals, are characterized by cyclical shifts in local population densities (Agrell et al 1995;Klemola et al 2000a), but the mechanisms underpinning these fluctuations are still a topic of debate (Agrell et al 1995;Klemola et al 2000b;Jiang & Shao 2003;Stenseth et al 2003;Hornfeldt et al 2005). Previously, many studies have focused on predatorvole interactions as the prime mechanism determining vole cycles (Hansson 1987;Henttonen et al 1987;Hanski et al 1993;Klemola et al 2000a).…”

Relationship Between Ljungan Virus Antibodies, HLA-DQ8, and Insulin Autoantibodies in Newly Diagnosed Type 1 Diabetes Children

“…However, climate changes during the last decade are thought to reduce the fluctuating population pattern (20). The time delay of about 2-3 years from vole population peak to T1D incidence peak may no longer be possible to document.…”

“…Levels of LVAb were increased in young age at onset of T1D in children but a possible relationship to the incidence of T1D could either not be determined (28) or was suggestive (31). In our previous investigation, LVAb were studied in children from the Northern part of Sweden where the multiannual population cycles of bank voles now show a trend towards reduced fluctuation pattern (20). LV is thought to have a continuous worldwide presence in voles, although its possible role as a human pathogen remains unclear (22).…”

Multiple Effects of Changes in Arctic Snow Cover

“…This decreases the available subnivean space, causing a decline in rodent population growth rates. A collapse in rodent population size has cascading effects on predators such as the Tengmalm's owl (Aegolius funereus) (Hörnfeldt et al 2005) and their alternative prey, such as ground-nesting birds (Kausrud et al 2008).…”