1. Department of Science and Primary Industries, Ara Institute of Canterbury, PO Box 540, Christchurch 8140, New Zealand
2. School of Biological Sciences, University of Canterbury, Christchurch 8011, New Zealand
3. Department of Geological Sciences, University of Canterbury, Christchurch 8011, New Zealand
4. Ecological Stable Isotope Laboratory, National Institute of Water & Atmospheric Research, Wellington 6021, New Zealand
5. Palaecol Research Ltd, Christchurch 8042, New Zealand