When an ecological regime shift is really just stochastic noise

Abstract

Populations of marine species wax and wane over time and space, reflecting environmental forcing, biological dynamics, and in some cases human perturbations, such as fishing, habitat destruction, and climate change (1). The growing availability of multidecadal observational records opens new windows on how ocean ecosystems function, but the analysis and interpretation of such long time-series also requires new mathematical tools and conceptual models (2). Population time-series often show strong variations at decadal time-scales, and a central question is whether this arises from nonlinear biological processes or simply tracking of external physical variability (3). Borrowing from climate research, Di Lorenzo and Ohman (4) develop a new approach for deciphering links between physical forcing and biological response, using as a test case time-series of marine zooplankton abundances off the coast of California.