Journal article

Accelerating across the landscape: The energetic costs of natal dispersal in a large herbivore


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Publication Details

Author list: Benoit L, Hewison AM, Coulon A, Debeffe L, Gremillet D, Ducros D, Cargnelutti B, Chaval Y, Morellet N

Publisher: Wiley

Publication year: 2019

Journal: Journal of Animal Ecology

Start page: 1

End page: 13

Total number of pages: 13

ISSN: 0021-8790

eISSN: 1365-2656


Abstract

1. Dispersal is a key mechanism enabling species to adjust their geographic range to
rapid global change. However, dispersal is costly and environmental modifications
are likely to modify the cost–benefit balance of individual dispersal decisions, for
example, by decreasing functional connectivity.
2. Dispersal costs occur during departure, transience and settlement, and are levied
in terms of energy, risk, time and lost opportunity, potentially influencing individual
fitness. However, to the best of our knowledge, no study has yet quantified
the energetic costs of dispersal across the dispersal period by comparing dispersing
and philopatric individuals in the wild.
3. Here, we employed animal‐borne biologgers on a relatively large sample (N = 105)
of juvenile roe deer to estimate energy expenditure indexed using the vector
of dynamic body acceleration and mobility (distance travelled) in an intensively
monitored population in the south‐west of France. We predicted that energy expenditure
would be higher in dispersers compared to philopatric individuals. We
expected costs to be (a) particularly high during transience, (b) especially high in
the more fragmented areas of the landscape and (c) concentrated during the night
to avoid disturbance caused by human activity.
4. There were no differences in energy expenditure between dispersers and
philopatric individuals during the pre‐dispersal phase. However, dispersers expended
around 22% more energy and travelled around 63% further per day than
philopatric individuals during transience. Differences in energy expenditure were
much less pronounced during the settlement phase. The costs of transience were
almost uniquely confined to the dawn period, when dispersers spent 23% more
energy and travelled 112% further than philopatric individuals. Finally, the energetic
costs of transience per unit time and the total distance travelled to locate a
suitable settlement range were higher in areas of high road density.
5. Our results provide strong support for the hypothesis that natal dispersal is energetically
costly and indicate that transience is the most costly part of the process,
particularly in fragmented landscapes. Further work is required to link dispersal costs with fitness components so as to understand the likely outcome of further
environmental modifications on the evolution of dispersal behaviour.


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Last updated on 2019-10-12 at 12:25