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Do common dispersal influences inform a large lizard’s landscape-scale gene flow?

journal contribution
posted on 2023-02-03, 01:29 authored by Tim Jessop, P Smissen, JR Anson, Craig ShermanCraig Sherman, JM Sumner
The dispersal tendencies of individuals can provide an important adaptive basis to counter environmental and ecological variation to increase fitness and benefit populations. We evaluated whether indirect genetic-based measures of dispersal of a large monitor lizard (Varanus varius) were sex-biased and further covaried with putative demographic and ecological differences across a forest ecotone in Southern Australia. The mean corrected assignment index (i.e., mAIC) estimated that lace monitors had significant male-biased dispersal. There was strong evidence that common dispersal promoting influences, including lace monitor density and arboreal mammal prey availability, but not the overall male-biased sex ratio, differed with forest type across the ecotone. These different forest types influenced the extent of sex-biased dispersal, with lace monitors captured in banksia woodland having a significant male bias in dispersal, whilst lace monitors sampled in adjacent eucalypt forest showed no difference in assignment values indicating no sex-biased dispersal. However, individual-based spatial autocorrelation analyses and mixed effect models indicated no spatial mediated genetic structuring nor evidence of sex or habitat-related effects. Estimates of recent migration (i.e., < 3 generations) indicated strong and symmetrical migration between banksia woodland and eucalypt forest patches suggesting limited habitat resistance to gene flow across an ecotonal landscape. Not discounting method-specific evidence for male- and forest-type-biased dispersal, the absence of spatial genetic structuring suggests lace monitors retain a high dispersal capacity. An absence of landscape-scale genetic structure is consistent with this species’s high vagility. This landscape-scale result is further supported because only the most significant biogeographic barriers (e.g., mountain ranges) impede gene flow within the species’ extensive range distribution, allowing for genetic structuring among populations.

History

Journal

Evolutionary Ecology

Volume

36

Pagination

987-1006

Location

Berlin, Germany

ISSN

0269-7653

eISSN

1573-8477

Language

English

Publication classification

C1 Refereed article in a scholarly journal

Issue

6

Publisher

Springer