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Evolution of predator dispersal in relation to spatio-temporal prey dynamics: how not to get stuck in the wrong place!

Travis JM, Palmer SC, Coyne S, Millon A, Lambin X - PLoS ONE (2013)

Bottom Line: We additionally demonstrate that the cost of dispersal can vary substantially across space and time.Perhaps as a consequence of current environmental change, many key prey species are currently exhibiting major shifts in their spatio-temporal dynamics.By exploring similar shifts in silico, we predict that predator populations will be most vulnerable when prey dynamics shift from stable to complex.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK. justin.travis@abdn.ac.uk

ABSTRACT
The eco-evolutionary dynamics of dispersal are recognised as key in determining the responses of populations to environmental changes. Here, by developing a novel modelling approach, we show that predators are likely to have evolved to emigrate more often and become more selective over their destination patch when their prey species exhibit spatio-temporally complex dynamics. We additionally demonstrate that the cost of dispersal can vary substantially across space and time. Perhaps as a consequence of current environmental change, many key prey species are currently exhibiting major shifts in their spatio-temporal dynamics. By exploring similar shifts in silico, we predict that predator populations will be most vulnerable when prey dynamics shift from stable to complex. The more sophisticated dispersal rules, and greater variance therein, that evolve under complex dynamics will enable persistence across a broader range of prey dynamics than the rules which evolve under relatively stable prey conditions.

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Related in: MedlinePlus

Predators are choosier and take more steps when the per-step cost of dispersal is low.Here we illustrate results obtained when the predators evolve a stopping rule that is sensitive to the ratio of prey per predator. The mean number of steps taken by predators is shown for a range of prey r and per-step mortality cstep in A. In B, C and D, we show the mean stopping rules that evolve for cstep = 0.02, 0.04 and 0.10, respectively.
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pone-0054453-g003: Predators are choosier and take more steps when the per-step cost of dispersal is low.Here we illustrate results obtained when the predators evolve a stopping rule that is sensitive to the ratio of prey per predator. The mean number of steps taken by predators is shown for a range of prey r and per-step mortality cstep in A. In B, C and D, we show the mean stopping rules that evolve for cstep = 0.02, 0.04 and 0.10, respectively.

Mentions: Allowing the predators to evolve a stopping rule that accounts for the ratio between prey and predator density resulted in a slight increase in the mean number of dispersal steps (Fig. 3A). However, the evolved stopping rule changed considerably (compare Fig. 3B with 2C). At low per-step mortality, under stable and relatively low prey conditions (Fig. 3B; red line), the predators could afford to disperse until finding at least 0.5 prey units per predator present, but as prey density increased (orange line) even this low risk of mortality was not selected for, and most predators stopped immediately, whereas in the cyclic and chaotic prey regions, the stopping rules were very similar, and predators continued to move until 1.0 to 1.5 prey units per predator were encountered. However, as predator mortality was increased, the stopping rules changed to reflect the greater risk of taking more steps (Fig. 3C–D). Under stable prey conditions, predators tended to stop after one step, regardless of the prey density or how many competitors were present. In the cyclic prey region, the threshold prey per predator became strongly dependent on prey r (yellow and green lines), whereas it was independent of r at low mortality risk (coincident yellow and green lines in Fig 3B). In the chaotic prey region, the threshold levels of prey per predator declined sharply with increasing mortality risk, and predators tended to stop when only a moderate level of ∼0.5 prey units per predator was encountered.


Evolution of predator dispersal in relation to spatio-temporal prey dynamics: how not to get stuck in the wrong place!

Travis JM, Palmer SC, Coyne S, Millon A, Lambin X - PLoS ONE (2013)

Predators are choosier and take more steps when the per-step cost of dispersal is low.Here we illustrate results obtained when the predators evolve a stopping rule that is sensitive to the ratio of prey per predator. The mean number of steps taken by predators is shown for a range of prey r and per-step mortality cstep in A. In B, C and D, we show the mean stopping rules that evolve for cstep = 0.02, 0.04 and 0.10, respectively.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569443&req=5

pone-0054453-g003: Predators are choosier and take more steps when the per-step cost of dispersal is low.Here we illustrate results obtained when the predators evolve a stopping rule that is sensitive to the ratio of prey per predator. The mean number of steps taken by predators is shown for a range of prey r and per-step mortality cstep in A. In B, C and D, we show the mean stopping rules that evolve for cstep = 0.02, 0.04 and 0.10, respectively.
Mentions: Allowing the predators to evolve a stopping rule that accounts for the ratio between prey and predator density resulted in a slight increase in the mean number of dispersal steps (Fig. 3A). However, the evolved stopping rule changed considerably (compare Fig. 3B with 2C). At low per-step mortality, under stable and relatively low prey conditions (Fig. 3B; red line), the predators could afford to disperse until finding at least 0.5 prey units per predator present, but as prey density increased (orange line) even this low risk of mortality was not selected for, and most predators stopped immediately, whereas in the cyclic and chaotic prey regions, the stopping rules were very similar, and predators continued to move until 1.0 to 1.5 prey units per predator were encountered. However, as predator mortality was increased, the stopping rules changed to reflect the greater risk of taking more steps (Fig. 3C–D). Under stable prey conditions, predators tended to stop after one step, regardless of the prey density or how many competitors were present. In the cyclic prey region, the threshold prey per predator became strongly dependent on prey r (yellow and green lines), whereas it was independent of r at low mortality risk (coincident yellow and green lines in Fig 3B). In the chaotic prey region, the threshold levels of prey per predator declined sharply with increasing mortality risk, and predators tended to stop when only a moderate level of ∼0.5 prey units per predator was encountered.

Bottom Line: We additionally demonstrate that the cost of dispersal can vary substantially across space and time.Perhaps as a consequence of current environmental change, many key prey species are currently exhibiting major shifts in their spatio-temporal dynamics.By exploring similar shifts in silico, we predict that predator populations will be most vulnerable when prey dynamics shift from stable to complex.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK. justin.travis@abdn.ac.uk

ABSTRACT
The eco-evolutionary dynamics of dispersal are recognised as key in determining the responses of populations to environmental changes. Here, by developing a novel modelling approach, we show that predators are likely to have evolved to emigrate more often and become more selective over their destination patch when their prey species exhibit spatio-temporally complex dynamics. We additionally demonstrate that the cost of dispersal can vary substantially across space and time. Perhaps as a consequence of current environmental change, many key prey species are currently exhibiting major shifts in their spatio-temporal dynamics. By exploring similar shifts in silico, we predict that predator populations will be most vulnerable when prey dynamics shift from stable to complex. The more sophisticated dispersal rules, and greater variance therein, that evolve under complex dynamics will enable persistence across a broader range of prey dynamics than the rules which evolve under relatively stable prey conditions.

Show MeSH
Related in: MedlinePlus