CONSIDERABLE controversy exists over the role of density-dependentprocesses in controlling animal population size. In populations that fluctuatecyclically or erratically, for example many voles andinsects1,2, theory predicts that either density-dependence isweak1,3, or that density-dependent responses lag behinddensity4–6. One key mechanism for laggeddensity-dependence is a delay in regeneration of food resources following heavyexploitation. Here we show that meadow vole (Microtuspennsylvanicus)populations respond immediately to high density by reducingbreeding effort and hence population growth, disproving the hypothesis thatdensity-dependence is weak. In addition, vole populations do not show a delayin growth following marked reduction in plant biomass (their source of food andcover). We conclude that intrinsic density-dependence processes tend tostabilize vole populations, and that cyclic dynamics are not caused by laggedeffects of resource exploitation.

Abstract Mortality rates often depend on the size of a population. Using ideal free theory to model the optimal timing of reproduction in model populations, I considered how the specific relationship between density-dependent offspring mortality and population size affects the optimal temporal... mehr

Copyright: Copyright 1999 Kluwer Academic Publishers mehr

Summary Predator-prey studies in semi-arid eastern Australia demonstrated that populations of rabbits (Oryctolagus cuniculus) could be regulated by predators. The functional, numerical and total responses of foxes (Vulpes vulpes) to rabbits and the numerical response of feral cats (Felis catus)... mehr

Copyright: Copyright 1992 Springer-Verlag mehr

A central issue in ecology lies in identifying the importance of resources, natural enemies and behaviour in the regulation of animal populations. Much of the debate on this subject has focused on animals that show cyclic fluctuations in abundance. However, there is still disagreement about the... mehr