Local population dynamics of gray wolves Canis lupus and Eurasian lynx Lynx lynx exhibit consistency with intraspecific contest competition models

Abstract

In Europe, the gray wolf and Eurasian lynx populations are recovering after various levels of persecution. The two species differ in their social structure and spatial patterns of aggregation. Using model selection, we investigated the consistency of the available time series data on local wolf and lynx sub-populations with a number of single-species population growth models that pertain to two types of intraspecific competition, namely, scramble (SC) and contest competition (CC), and reflect random (R) or aggregated (A) distribution of individuals. The applied models of population growth—the Ricker (SCR), Skellam (CCR), Hassell (SCA), and Beverton–Holt (CCA) models—were all parameterized in terms of intrinsic growth rate and carrying capacity with unified definitions. The projected carrying capacity was allowed to show a temporal trend, which was justified by an observed increase in prey abundance in recent decades. For both species, the models pertaining to contest competition outperformed the scramble competition models, and the Beverton–Holt model had the greatest weight. However, for the lynx, the difference of performance between the scramble and contest competition models was considerably smaller than that for the wolves. In most of the models, when it was meaningful, an optional time lag operator was added to account for a delay in individual maturity and reproduction. However, the models with a time lag had a worse fit than the models without it. This study promotes the application of population models that reflect intraspecific competition for modeling population dynamics in a single- or multi-species framework.