Patterns and predictors of fish dispersal in rivers

Abstract

Quantifying fish dispersal and identifying its general predictors is key for understanding temporal patterns in population dynamics, emigration and immigration, meta‐community dynamics, many ecological processes and predicting recovery time or population responses to environmental changes. This is the first comprehensive quantitative meta‐analysis of heterogeneous freshwater fish movement, aiming to determine mobile and stationary shares of fish communities, their dispersal distances and key predictors of dispersal patterns. By reviewing and analysing 160 empirical data sets from 71 studies covering 62 fishes in streams, it goes beyond previous studies of salmonids’ heterogeneous movement. Based on fitted leptokurtic dispersal kernels, the movement distances of (i) a stationary component (σstat) and (ii) a mobile component (σmob) as well as the (iii) share of each component (p) were calculated. The median movement distance of the stationary and mobile component of a fish population was 36.4 and 361.7 m, respectively. The share of the stationary individuals was high (median = 66.6%), but unrelated to movement distance. Single and multiple linear regressions as well as mixed‐effects models revealed movement distances positively related to fish length, aspect ratio of the caudal fin, stream size and duration of the study. Furthermore, movement distance differed between taxonomic families. The quantitative parameters of heterogeneous fish movement provided are prerequisite to estimate time lags in fish response to river rehabilitation, temporal patterns in species dispersal, and minimum effective size of potential founder populations for species conservation and stock recovery based on minimum numbers of specimen to disperse.

Evaluating the effectiveness of restoring longitudinal connectivity for stream fish communities: towards a more holistic approach

“…Although such species do not migrate between different habitats they, like all river animals, rely on dispersal potential between habitat patches for population persistence and recolonization (Albanese et al 2009;Urban et al 2009;Pépino et al 2012;Radinger and Wolter 2014). Relatively little is known about the effect of longitudinal continuum restoration for river fishes, especially in degraded and rehabilitated habitats, despite its crucial importance for species distribution, species turnover and recolonization of newly available habitats (Detenbeck et al 1992;Albanese et al 2009) and for gene flow (Hanski 1998).…”

Risk taking not foraging behavior predicts dispersal of recently emerged stream brook charr (Salvelinus fontinalis)

“…Leptokurtosis in dispersal kernels has been attributed to underlying differences in behavior that involve routine daily activities (Fraser et al 2001, Coombs andRodríguez 2007). If this explanation holds, individuals comprising the fat tails of the distribution could be behaviorally distinct; inter-individual differences could then be important to understanding ecological processes such as colonization of new habitats or the spread of diseases (Kot et al 1996, Dybiec et al 2009, Cote et al 2010b, Radinger and Wolter 2013. The ability to predict which individuals are likely to exhibit long distance movement, and the magnitude of such movements, could help understand key ecological processes by targeting individuals that are most influential to the process of interest Watters 2005, Phillips et al 2009).…”

Climate change poised to threaten hydrologic connectivity and endemic fishes in dryland streams

“…Species-specific thresholds were estimated by fitting leptokurtic dispersal kernels presented in meta-analysis by Radinger and Wolter (56) where median annual movement rate (km) of mobile individuals is predicted as a function of fish morphology (body length and aspect ratio of the caudal fin) and river characteristics (Strahler stream Overall DCI future values represent the midcentury simulation period. Percent reduction [calculated as (DCI future − DCI current )/DCI current × 100] in mean daily DCI values between current and midcentury simulation periods is reported for the entire year (overall) and seasonally according to estimated fish species' dispersal distance.…”