Functional connectivity and population persistence in woodland birds: insights for management from a multi-species conservation genetics study

ABSTRACT

Conservation management of wildlife benefits from understanding the genetic factors underlying individual fitness and population evolution. Habitat loss and fragmentation reduce genetic diversity and functional connectivity, limiting population persistence and adaptation to changing environments. Here we review and synthesise results from the Birds in Fragmented Landscapes program in central Victoria, Australia. Building on research on patterns of occurrence of woodland-dependent bird species, we conducted conservation genetic studies of ~3,500 individuals from 10 woodland bird species sampled in twelve 100 km² ‘landscapes’ with different levels of habitat loss, to assess multiple conservation-relevant processes of response to habitat alteration. This program employed connectivity modelling and landscape-, acoustic- and population genetic analyses to understand mobility of birds, their genes and songs at different scales, relating these elements of functional connectivity to landscape structure for each sex in each species. At the regional scale, most species displayed unexpectedly high levels of genetic connectivity. At local-scales, there were strong signals of disrupted population processes (e.g. mating system) and reduced functional connectivity for several more-mobile and all less-mobile ‘decliner’ species. This underlines that high genetic connectivity does not necessarily signal genetically and demographically healthy populations. In some species, declines in mobility were greater in one sex but not necessarily the more philopatric sex. We derive conservation management recommendations in five concept areas: maintain existing and restore degraded habitat, reconnect the landscape, use species- and sex-specific information where possible, work across multiple scales, and conserve evolutionary processes (by genetic management where appropriate).

KEYWORDS:

• Woodland birds
• functional connectivity
• structural connectivity
• landscape genetics
• evolutionary fitness
• population persistence

Acknowledgements

This work would not have been possible without Naoko Takeuchi, who lived and breathed the most challenging field and lab components of this project. We thank our co-authors and people acknowledged on the earlier publications, field volunteers and the Friends of the Helmeted Honeyeater, as well as the ABBBS, wildlife permissions and Birdlife Australia for their support. We thank Kate Buchanan, Helen Taylor and two anonymous referees for comments that improved earlier versions of this paper. We also thank Helen Taylor, Anna Kearns and Kate Buchanan for the invitation to be part of this special issue.

Disclosure statement

The authors have no competing interests or financial benefit arising from this work.

Ethics

Samples were collected under wildlife, ethics and Australian Bird and Bat Banding Scheme permissions as given in the original publications.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by Australian Research Council grants LP0776322 and LP160100482 (all details given in original publications). Further support came from Monash University, Birdlife Australia, and the Holsworth Wildlife Research Endowment.