Boom‐bust dynamics in biological invasions: towards an improved application of the concept

Abstract

Boom-bust dynamics -the rise of a population to outbreak levels, followed by a dramatic decline -have been associated with biological invasions and offered as a reason not to manage troublesome invaders. However, boom-bust dynamics rarely have been critically defined, analyzed, or interpreted. Here, we define boom-bust dynamics and provide specific suggestions for improving the application of the boom-bust concept. Boom-bust dynamics can arise from many causes, some closely associated with invasions, but others occurring across a wide range of ecological settings, especially when environmental conditions are changing rapidly. As a result, it is difficult to infer cause or predict future trajectories merely by observing the dynamic. We use tests with simulated data to show that a common metric for detecting and describing boom-bust dynamics, decline from an observed peak to a subsequent trough, tends to severely overestimate the frequency and severity of busts, and should be used cautiously if at all. We review and test other metrics that are better suited to describe boom-bust dynamics. Understanding the frequency and importance of boom-bust dynamics requires empirical studies of large, representative, long-term data sets that use clear definitions of boom-bust, appropriate analytical methods, and careful interpretations.

Boom‐bust like dynamics of invasive black bullhead (Ameiurus melas) in Lake Sava (Serbia)

“…Although the boom‐bust phenomenon is a well‐known concept in conservation and management of non‐native invasive species, there is a lack of consensus on both its actual frequency, defining criteria and decline thresholds (Simberloff & Gibbons, ; Strayer et al., ). Based on the CPUE values observed in this study, however, it was assumed that a boom‐bust like phenomenon occurred in the black bullhead population of Lake Sava.…”

“…The possible causes of boom‐bust dynamics have been divided into two categories (Strayer et al., ): (a) mechanisms typically associated with invasions, and (b) general ecological mechanisms. Regarding black bullhead in Lake Sava, such dynamics probably result from an interaction between a time lag in density‐dependent populations and recovery from disturbance.…”

Long‐term population dynamics of dreissenid mussels (Dreissena polymorpha and D. rostriformis): a cross‐system analysis

“…There is a persistent idea that populations of biological invaders tend to decline steeply after an initial boom period (e.g., Simberloff and Gibbons , Strayer et al. ). Such boom–bust dynamics would be of obvious importance to management; if the severe impacts during the boom period could be tolerated or mitigated, then perhaps little or no management would be required after the population crashed.…”

Habitat explains patterns of population decline for an invasive crayfish

“…Yet reviews by Simberloff and Gibbons () and Strayer et al. () found that population declines of established invasive species are infrequently documented owing to the scarcity of long‐term data sets, and attributing mechanisms to population declines that are observed is similarly rare. Most recently, Strayer et al.…”