Quantifying migratory connectivity: current methods and future perspectives

Migratory connectivity refers to the spatiotemporal linkage between breeding and nonbreeding ranges where individuals spend different phases of their annual cycle. However, several different definition and methods for quantifying this property have been proposed in the literature, and no general agreement on a measure of migratory connectivity exists. We propose here a theoretical framework that unifies the two most commonly used measures for quantifying connectivity i.e. the Mantel correlation coefficient between the position of the individuals in different phases of their annual lifecycle and the so-called MC coefficient, a weighted average correlation between distances among separate areas among which the population of a specie move. We also propose the solution of some practical problems that arise in particular cases for which the MC coefficient in undefined. We also propose further theoretical development of this concept aiming at linking more tightly the concepts of migratory and ecological connectivity