Speed and directedness predict colonization sequence post-disturbance

John V. Gatto, Joel C. Trexler

Research output: Contribution to journalArticlepeer-review


Foundational ecological models characterize dispersal with two behavioral traits, speed and directional bias. We hypothesized that these two traits can predict the order of colonization by fishes in a heterogenous landscape. Colonization patterns following hydrological disturbance were documented from a 20-year multi-site time series of marsh fish, and we evaluated the ability of a two-parameter model to predict these patterns. The maximum aerobic swimming speed (U-CRIT) for six coexisting fish species were estimated using endurance tests; field estimates of directedness and swimming speed were previously documented using encounter samplers. We incorporated interspecific variation in speed, direction, and density into several Agent Based Models to simulate dispersal following disturbance. Six virtual "species" with varying levels of directedness, "swam" in an artificial environment to reach a refuge habitat. The time of first arrival for each species was saved at the end of each run and used to calculate the probability of arrival order. Our simulated results generated predictions on order of arrival consistent with observed colonization patterns in our long-term dataset. Swim tunnel results revealed that fast (highU(CRIT)) estimates were characteristic of early colonizing species; whereas, slow (lowU(CRIT)) estimates were characteristic of late colonizing species. Directional bias better predicted order of arrival than speed and was robust to inter-specific variation in density. This study demonstrated that two parameters were adequate to predict the order of species colonization in a complex landscape. These results support the use of relatively simple trait-based models to generate realistic community assembly dynamics.
Original languageEnglish (US)
Pages (from-to)713-727
Number of pages15
Issue number3
StatePublished - Jul 2020


  • INHS
  • Primary succession
  • Dispersal
  • Critical swimming speed
  • Functional traits
  • Wetland
  • Diffusion model

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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