The role of the male flower spike as a cue for selective grazing in bladder saltbush

D. Walsh; R. Sinclair; M. H. Andrew; D. Coleman

doi:10.1071/RJ05008

RESEARCH ARTICLE

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The role of the male flower spike as a cue for selective grazing in bladder saltbush

D. Walsh ^A ^D , R. Sinclair ^B , M. H. Andrew ^C and D. Coleman ^B

+ Author Affiliations

- Author Affiliations

^A Centralian Land Management Association, PO Box 2534, Alice Springs, NT 0871, Australia.

^B University of Adelaide, Adelaide, SA 5005, Australia.

^C URS Australia – NRM Group, 25 North Tce, Hackney, SA 5069, Australia.

^D Corresponding author. Email: ems@clma.com.au

The Rangeland Journal 27(2) 97-103 https://doi.org/10.1071/RJ05008
Submitted: 1 August 2005 Accepted: 24 August 2005 Published: 21 November 2005

Abstract

This paper reports the results of three cafeteria trials used to study palatability variation between the sex phenotypes of bladder saltbush (Atriplex vesicaria Heward ex Benth.). The results of the first trial show that Merino sheep preferentially grazed female samples compared to male ones, which supported earlier paddock-scale grazing trials and observations. In the second trial, the removal of male flower spikes led to increased consumption of male samples, suggesting that male flower spikes contain a grazing deterrent. The third trial showed that sheep were able to detect male material with or without spikes even when it was completely hidden within female plant material. In combination with observations made during the trials, these results suggest that there is a grazing deterrent present in male plants and that sheep use the male flower spike primarily as a visual cue when making grazing decisions.

Additional keywords: Atriplex vesicaria, Australian merino, female, palatability.

Acknowledgments

We are indebted to the Nicolson families of Middleback and Roopena stations and the many people who assisted with the field work. We are grateful to Dr D. Carl Freeman and two anonymous referees for reviewing a draft of the manuscript. This research was funded by an International Wool Secretariat Postgraduate Scholarship and The University of Adelaide, and was conducted as part of the Middleback Field Centre research program. Animal ethics committee approval S/14/94.

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¹Senior author’s maiden name.