Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics

Abstract

Knowledge of the ecological and evolutionary causes of dispersal can be crucial in understanding the behaviour of spatially structured populations, and predicting how species respond to environmental change. Despite the focus of much theoretical research, simplistic assumptions regarding the dispersal process are still made. Dispersal is usually regarded as an unconditional process although in many cases fitness gains of dispersal are dependent on environmental factors and individual state. Condition-dependent dispersal strategies will often be superior to unconditional, fixed strategies. In addition, dispersal is often collapsed into a single parameter, despite it being a process composed of three interdependent stages : emigration, inter-patch movement and immigration, each of which may display different condition dependencies. Empirical studies have investigated correlates of these stages, emigration in particular, providing evidence for the prevalence of conditional dispersal strategies. Ill-defined use of the term ' dispersal', for movement across many different spatial scales, further hinders making general conclusions and relating movement correlates to consequences at the population level. Logistical difficulties preclude a detailed study of dispersal for many species, however incorporating unrealistic dispersal assumptions in spatial population models may yield inaccurate and costly predictions. Further studies are necessary to explore the importance of incorporating specific condition-dependent dispersal strategies for evolutionary and population dynamic predictions.

Local and neighboring patch conditions alter sex‐specific movement in banana weevils

“…These results suggest that individuals may also perceive local conspecific densities as a proxy of competiveness and may perceive neighboring conspecific densities as a proxy for patch quality. Therefore, our results show that density‐dependent movement in C. sordidus is context dependent, which agrees with current dispersal theory (Bowler and Benton 2005; Clobert et al. 2009).…”

“…2011). Positive density‐dependent movement has been well documented by experimental studies (for a review, see Bowler and Benton 2005). Although negative density‐dependent movement is also commonly found for mammals and birds (for a review, see Matthysen 2005), it has seldom been documented for insects (Roland et al.…”

“…In addition to being influenced by population density, the movement decision may also be influenced by inbreeding, kin competition, intra‐ and interspecific competition, or intra‐ and intersexual competition (Gandon 1999; Bowler and Benton 2005; Clobert et al. 2009; Trochet et al.…”

“…However, theoretical studies that focus on the evolution of sex‐biased movement have generally assumed that movement is a fixed trait in individuals, which is not always the case (Bowler and Benton 2005). In addition, most experimental studies have examined the effect of sex‐biased movement on the variation in the local sex ratio of populations and have not considered how sex‐biased movement is a flexible response to variation in the local sex ratio and, hence, to variation in intra‐ and intersexual competition.…”

Effects of rearing conditions on natal dispersal processes in a long‐lived predator bird

“…An individual’s internal state can provide information on the fitness potential of its environment, thereby affecting its decision to stay or leave its natal area (Clobert et al., 2012). In other words, the costs and benefits of natal dispersal are influenced by the internal state of individuals and by environmental conditions experienced both in the natal area and in future breeding sites (Acker et al., 2018; Bonte et al., 2012; Bowler & Benton, 2005; Clobert et al., 2009; del Mar Delgado, Penteriani, Revilla, & Nams, 2010; Rémy, Le Galliard, Gundersen, Steen, & Andreassen, 2011). Thus, both modeling and empirical studies indicate that natal dispersal behavior often represents a plastic‐, phenotype‐, and condition‐dependent strategy (Bonte et al., 2012; Clobert et al., 2012; Rémy et al., 2011).…”