Transient Dynamics

While much of theoretical ecology has focused on the study of long-term asymptotic dynamics of populations, a growing realization is that the study of dynamics on more ecologically relevant timescales is of equal or greater importance. Often, dynamics that occur on shorter, ecologically relevant, timescales are referred to as transient dynamics, and include examples such as disease outbreaks and regime shifts. While any perturbation or environmental change that moves a system away from equilibrium will trigger a transient, this article focuses specifically on those “long transients” whose impact persists over a meaningful timescale (very roughly, dozens of generations or longer). Transient dynamics often lead to significant qualitative changes in an ecological system’s state that can occur with little to no warning at all. In the context of management, transients can cloud the manager’s judgment of the stability of a system. It would be easy to assume the system is in a stable state when it may be near a regime shift (long transients), which may result in inaccurate predictions of long-term dynamics based solely on short-term data. Consequently, the study of transient dynamics involves several avenues, including mathematical theory, management implications, and empirical understanding. New literature in these areas has begun to emerge. The notion of transient dynamics was discussed as early as the mid-1900s, where the idea that steady states are the most ecologically relevant quantities was challenged and the exploration of more complex ecological dynamics was sought. In more recent literature, transient dynamics, the underlying theory, empirical evidence, management implications, and ecological implications have all been more explicitly discussed. One major challenge when dealing with transient dynamics is the infancy of the mathematical theory that underpins much of the necessary analysis. Additionally, the implications transient dynamics have on management and ecological applications are still being developed. However, the significance of transients is now appreciated and research in such areas is attracting much attention. Several important avenues for future research have been made apparent in ecology, and new insights continue to be developed.