Jupp, K. L., Partridge, T. R., Hart, D. E., & Marsden, I. D. (2007, May). Ecology of the Avon-Heathcote Estuary: Comparative salt marsh survey 2006-2007. University of Canterbury.

Prepared for the Avon-Heathcote Estuary Ihutai Trust in 2007, this research report monitored and mapped the area of salt marsh vegetation in the Ihutai estuary during the summer of 2006-2007. Its purpose was to act as a comparative study to research conducted by McCombs and Partridge (1992) in order to describe the changes undergone by Ihutai salt marsh communities in the last 15 years. This study was significant because as cities continue to grow, salt marshes around the world have continued to decline due to high disturbance from human development, draining, and wetland reclamation. The report emphasised that monitoring salt marsh communities is crucial for their sustainable management and preservation.

The 2007 study used the same sites as McCombs and Partridge (1992) and found a total of 12 vegetation types compared to 15 found in 1992. Overall, the researchers found that Ihutai salt marsh vegetation had changed since 1992. Less salt-tolerant plants had largely replaced salt-tolerant plants, likely due to increased fine sedimentation from developments. Sandy Point and areas above Ferrymead were the most unstable and had the greatest vegetation change since 1992, while salt marsh near the Avon River was the most stable. To encourage protection of salt marsh in the Ihutai estuary, the 2007 report recommended that another report be completed within 8 to 10 years.

1992 Study:

• McCombs, K and Partridge, T. R. 1992. The vegetation of the Avon-Heathcote Estuary, Christchurch. Unpublished report for the Christchurch City Council Parks Unit. Landcare Research contract report No. 92/B. Ecan Record No. LI1C/7502. Christchurch, Christchurch City Council.