Synchrony of spatial populations: heterogeneous population dynamics and reddened environmental noise

Abstract

Many species exhibit widespread spatial synchrony in population fluctuations. This pattern is of great ecological interest and can be a source of concern when a species is rare or endangered. Moran's theorem suggests that if two (or more) populations sharing a common linear density-dependence in the renewal process are disturbed with correlated noise, they will become synchronized with correlation matching the noise correlation. In this report, correlation of nonidentical populations that are described by linear and stationary autoregressive processes is analyzed. We show that the expected spatial synchrony between two populations can be decomposed into two multiplicative components. One is the demographic component related to the values of the autoregressive coefficients and the noise color. The other is the spatial correlation of the environmental colored noise. The main results are consistent with the predictions of previous experiments and simulations, and the importance of this report is to provide theoretical support.

Rainbow trout (Oncorhynchus mykiss) habitat overlap with wild Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in natural streams: do habitat and landscape factors override competitive interactions?

“…In spatiotemporal population dynamics, there are two components of variation: environmental correlations and a demographic component, i.e., densitydependence (Liu et al 2009). In our analyses, the density-dependent component was incorporated only for Chinook salmon (via REDDS), and it was very significant in multivariate and univariate models, as has been found previously in Chinook salmon populations in the study area (Copeland et al 2008).…”

Enhanced Moran effect by spatial variation in environmental autocorrelation

“…The colour of environmental noise can have a substantial influence on population dynamics and persistence 26,[30][31][32][33][34][35] but, although relevant, its effect on population synchrony has rarely been addressed. Previous theoretical investigations revealed that reddened environmental noise may intensify spatial synchrony 19,30,[36][37][38] . These investigations, however, were restricted to the case of identical noise colours in all populations, despite the fact that empirical studies of a wide range of environmental variables have revealed substantial variations in noise colour between geographic regions and on gradients from land to the ocean 24,26,29,[39][40][41] .…”