Spatially-coupled food and propagule supply influence meta-population dynamics

Spatial variation between patches can affect ecological and evolutionary dynamics within a metapopulation. Physical factors (e.g. precipitation, wind, currents) and limited resources (e.g. shelter, food) that control demographic rates within individual patches are particularly important. In marine metapopulations, oceanographic patterns can create spatial covariation in the supply of nutrients, larval propagules dispersed from neighboring patches, and planktonic food. Here I use a bioenergetic model of a coral reef fish to evaluate how correlations between food and larval supply alter the dynamics of a two-patch metapopulation. The model assumes a non-mechanistic form of density-dependent mortality, but specifies food competition as the mechanism of density-dependent growth and fecundity. First, I use a stochastic model to study how increasing disparity between patches in food and larval supply translates to fluctuations in metapopulation size. I then demonstrate that the patch characterized by greater food supply, lesser larval supply, or greater food and larval supply serves as a source, contributing most to metapopulation persistence.