Abstract
Agricultural modification commonly leads to reductions in vegetation matrix quality and a resultant decrease in functional connectivity. In this study, a network analysis approach was used to assess the impact of agriculturally-induced reductions in vegetation matrix quality on the metapopulation dynamics of the critically endangered New Zealand grand skink (Oligosoma grande). Vegetation matrix quality was quantified in four sites exhibiting differing levels of modification within indigenous tussock grasslands in eastern Central Otago, New Zealand. Grand skink occupancy probability exhibited a positive correlation with the structural connectivity of primary habitat within the more modified study sites, whereas in the least modified site a complex matrix appeared to compensate for low structural connectivity. Results from this research indicate that the matrix is an important determinant of grand skink metapopulation dynamics and that an intricate balance exists between structural connectivity and the quality of the vegetation matrix. This research highlights the importance of assessing the impact of the matrix for individual species, particularly for conservation management.
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Acknowledgments
We are grateful to Phillip J. Seddon for comments on an earlier version of the manuscript. This research was supported by A University of Otago Postgraduate Scholarship, the Federation for Graduate Woman Brenda Shore Award and an award from the Miss E.L. Hellaby Indigenous Grasslands Research Trust. This research was undertaken under a Department of Conservation low impact research permit (#OT-27842-FLO). A number of GPS positions were kindly provided by K. Gebauer and the Department of Conservation. We are grateful for the support of landowners L. Watson, M. Sutton and G. Hand for access to private land. Deahn Donner and two anonymous reviewers provided helpful comments on the manuscript.
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Harris, K.M., Dickinson, K.J.M. & Whigham, P.A. Functional connectivity and matrix quality: network analysis for a critically endangered New Zealand lizard. Landscape Ecol 29, 41–53 (2014). https://doi.org/10.1007/s10980-013-9967-9
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DOI: https://doi.org/10.1007/s10980-013-9967-9