Dr Robyn Dunmore1, Dan Crossett Dan Crossett2,3, Professor David Schiel3
1SLR Consulting NZ Limited, Richmond, New Zealand, 2Cawthron Institute, Nelson, New Zealand, 3University of Canterbury, Christchurch, New Zealand
The November 2016 Kaikōura earthquake lifted land and seabed to varying degrees. Uplifted subtidal reefs have had to contend with altered wave and light climates, higher temperatures from heat waves, and increased turbidity due to erosion and riverine runoff. Initially, sites with high-degrees of uplift (~6 m) had extensive areas of bare rock that had been pushed up through the sand and gravel. Low- to mid-degrees of uplift (1 to 2.5 m) appeared to have had little effect on shallow subtidal rocky reef communities (in stark contrast to the intertidal zone), with diverse arrays of algae, invertebrates and fish still present. Similar results were found at all sites 1.5 years after the earthquake. However, from 2.5 years onwards, some low- to mid- uplift sites have distinct changes in algal communities. There was a sharp decline in large brown algae and an increase in red algal-dominated communities, probably due to a combination of an altered wave climate and increased temperatures. High uplift sites have had some recruitment of invertebrates and algae, but recovery has been slow overall and will likely take many more years because of continuing environmental change and limited propagule supply of key large brown algal species.
Presentation Slides – Robyn Dunmore
