Determinants of spatio-temporal outbreak dynamics of Geometrid moths populations

The cyclic outbreak dynamics of birch forest Geometrids in Fennoseandia (in particular the two species; the autumnal moth and the winter moth) is a very well—known phenomenon both among scientists aud lay people due its severe, large-scale impacts on the mountain birch forest ecosystem. Still important aspects of the spatio-temporal patterning of the outbreak dynamics as well as the underlying causal mechanisms are unknown. We here propose a 4-year project aimed at significantly improving on this state of affairs. The project will include: (1) state—of--the~art statistical analyses of a long-term qualitative dataset based on outbreak incidence reports at the scale of the Fennoscandian peninsula, (2) sampling aud analysis of new observational and experimental data of moth abundance dynamics aud moth-parasitoid interactions from specifically dedicated transeci studies in coastal birch forests in northern Norway, and (3) analyses of mathernatical models to validate the interpretation of correlative studies based on field data- The proposed set of subprojects should enable us to demonstrate quantitative spatial aspects of the outbreak dynamics (e.g. scale of spatial population synchrony as well as speed aud directionality of travelling waves), the role of ecologica! barriers and parasitoids/predators in the spatial patterning of outbreaks aud, finally, the mechanisms underiying dynamic relations between the two main Geometrid moth species in the Fennoscandian mountain birch forest.