Rodent population dynamics in a primeval deciduous forest (Białowieża National Park) in relation to weather, seed crop, and predation

Abstract

dynamics in a primeval deciduous forest (Białowieża National Park) in relation to weather, seed crop, and predation. Acta theriol. 38: 199 -232. (Schreber, 1780) and yellow-necked mice Apodemus flavicollis (Melchior, 1834) were studied in 1959 -1991 in the pristine mature forest dominated by hornbeam Carpinus betulus and oak Quercus robur in Białowieża National Park (eastern Poland). The whole 33-year series, and particularly the detailed data from 1971 -1991, were related to weather data and seed crop o f hornbeam, oak, and maple Acer platanoides. Rodent numbers were very low in spring (April), then grew through summer due to repro duction. The annually highest numbers o f both species were recorded in autumn. W inter mortality was on average 77% o f autumn numbers of voles and 86% o f mice. Multiannual variations in numbers were large; the combined numbers of voles and mice showed a regular pattern of 2 years o f outbreak-crash (triggered by heavy mast production) and 4 -7 years of moderate, though variable, densities. Heavy seed crops (synchronous in oak, hornbeam and maple) occurred at 6-9-year intervals (in 1958, 1967, 1976, 1982, and 1989), and were triggered by warm June -July temperature in the preceding year (bud formation year). Outbreaks o f rodents were always preceded by winter breeding in mice and sometimes also in voles. Rodents reached highest numbers in autumn o f the year following the mast peaks. Then, they declined rapidly over winter to extremely low numbers in the following spring, summer and autumn. Such crashes were recorded after 4 out o f 5 outbreaks. In moderate years, summer and autumn numbers o f rodents correlated with food-related factors (seed crop, temperature affecting vegetation biomass), whereas spring numbers were shaped by density dependent winter mortality. Summer (July) numbers of mice in moderate years were a direct function of spring numbers o f overwintered adults ( R = 91%). Autumn (September) numbers o f mice were determined by tree seed crop o f the previous year (R = 32%). Summer numbers of voles depended on temperature in June -July ( R 2 = 29.5%), which most probably acted through an increased production o f herba ceous vegetation biomass. No ambient factors were found to explain variation in autumn numbers o f voles. In both species, the intensity of reproduction in autumn was inversely related to autumn numbers. In bank voles, high temperature in JulySeptember was conducive to prolonged breeding. Winter mortality of rodents was density dependent ( R 2 = 99% in mice and 92% in voles). Mast increased overwinter survival o f mice but not voles. Snow cover increased survival of bank voles. Density -dependent predation was the main agent o f rodent mortality in moderate years, whereas its role in outbreak-crash years has not yet been studied. The described pattern o f population dynamics o f forest rodents is regarded as typical for the decidu ous forests with Quercus in lowland, temperate Europe. Review o f literature showed that the heaviest seed crops of oaks (a...

Genetic variation in a fluctuating population of the yellow-necked mouse Apodemus flavicollis

“…Seasonal and multiannual fluctuations in population number were described by various authors in A. flavicollis from the Białowieża National Park (Adamczewska 1961, Grodziński et al 1966, Wójcik and Wołk 1985, Wołk and Kozłowski 1989. Pucek et al (1993) found that the extraordinarily high population numbers (outbreaks) in A. flavicollis occurred in 1977, 1983 and 1990 -one year after the mast (synchronous seed crop of oak, hornbeam, and maple) and was followed by rapid decline of numbers (crashes). All other years were characterized by intermediate abundance of mice.…”

Spatial and temporal variation in tree seed production and dispersal in a New Zealand temperate rainforest

“…Large irregular seed crops represent an important pulsed resource for birds, insects and mammals (Jensen 1982, Pucek et al 1993, Fitzgerald et al 1996, Pech et al 1999, Choquenot and Ruscoe 2000. In New Zealand, these high seedfall events result in a cascade of responses by both native birds and insects, and introduced mammals (Ruscoe et al 2005b, Kelly et al 2008.…”

Breeding of house mice and the mast seeding of southern beeches in the Orongorongo Valley, New Zealand

“…In this view, the Nothofagus/Mus system is a Southern Hemisphere analogue of Northern Hemisphere systems involving 168 New Zealand Journal of Zoology, 2004, Vol. 31 masting trees and seed predators (e.g., crossbill (Loxia curvirostris) breed throughout winter when conifers mast (Newton 1972cited Caughley & Sinclair 1994; Peromyscus and Tamias in North America respond numerically to masting of Quercus (Ostfeld et al 1996;Wolff 1996); Apodemus and Clethrionomys in Europe respond to masting of Quercus, Acer, and Carpinus (Flowerdew 1973;Jensen 1982;Hansson 1984;Pucek et al 1993)). …”