Life history mediated responses to weather, Phenology and large-scale population patterns

Abstract

Using a threshold-triggering framework, we extend the Moran effect to also cover timing of life history events. With two varieties of the model we demonstrate emergence of synchrony in seasonal and annual timing that levels off against distance between sampling sites compared. In the first model we address within-season timing over years. The Finnish data on leafing of European aspen support the model predictions in al detail explored. In the second example the focus is on annual match of seed production in the Finnish Scotch pine and Norway spruce. The model predictions find their match with the data. We show that it is possible to extend Moran's (1953) idea to encompass events not directly regulated by density-dependent feedback. It is perhaps not too surprising that phenological events can be synchronized in much the same way as population fluctuations.