Modelling dispersal: an eco‐evolutionary framework incorporating emigration, movement, settlement behaviour and the multiple costs involved

Abstract

Summary 1.Understanding the causes and consequences of dispersal remains a central topic in ecology and evolution. However, a mismatch exists between our empirical understanding of the complexity of dispersal and our representation of dispersal in models. While the empirical literature is replete with examples of condition dependence at the emigration, movement and settlement phases, models rarely incorporate realism or complexity to this degree. Nor do models often include the different costs associated with dispersal, which can themselves be linked to one or more of the three key phases. 2. Here, we propose that by explicitly accounting for emigration, movement and settlement (and the multiple costs associated with each) we can substantially improve our understanding of both the dispersal process itself and how dispersal traits trade off against other life-history characteristics. We explore some of these issues conceptually, before presenting illustrative results gained from a flexible individual-based model which incorporates considerable dispersal complexity. 3. These results emphasise the nonlinear interplay between the different dispersal stages. For example, we find that investment in movement ability (at a cost to fecundity) depends upon the propensity to emigrate (and vice versa). However, owing to selection acting at the metapopulation level as well as at the individual level, the relationship between the two is not straightforward. Importantly, the shape of the trade-off between movement ability and reproductive potential can strongly influence the joint evolution of dispersal parameters controlling the degree of investment in safer movement, the probability of emigration and the straightness of movement. 4. Our results highlight that the joint evolution of dispersal characteristics can have major implications for spatial population dynamics and we argue that, in addition to increasing our fundamental biological understanding, a new generation of dispersal modelling, which exploits recent empirical advances, can substantially improve our ability to predict and manage the response of species to environmental change.

When is dispersal for dispersal? Unifying marine and terrestrial perspectives

“…Dispersal is an outcome, or an emergent property, of a multi-stage process that includes a departure, transfer, and settlement stage Travis et al, 2012). At each stage, individuals potentially vary in multiple traits and multiple selection pressures can act on this individual variation (Ronce, 2007;Clobert et al, 2009).…”

Life history trade-offs imposed by dragline use in two money spiders

“…when the chances of reaching suitable habitat are low (Bonte et al, 2006). Costs incurred during different dispersal stages (initiation, transfer and settlement) eventually determine dispersal strategies and feed back among each other Delgado et al, 2014;Travis et al, 2012). We demonstrated here trade-offs between silk spinning and fitness-related life history components, with an overall effect under dietary restriction.…”

Carryover effects drive competitive dominance in spatially structured environments

“…Furthermore, carryover effects can alter dispersal decisions and capabilities (16,44). Recent work on condition-dependent dispersal and its implications for population dynamics is addressing this question already, although there seems to be little focus on multispecies impacts as of yet (44,(54)(55)(56)(57)(58)(59). In our experiment, we standardized dispersal to isolate carryover effects on species interactions.…”