GeoHazards cover story

Our article on the impacts of sea-level change was unexpectedly chosen as the cover story for the latest issue of GeoHazards, check it out here!

Relationship between sea-level change and loss of seaweed on a rocky shore

In this paper recent published in GeoHazards we evaluated the relationship between sea-level change and the severity of impacts in the major habitat-forming seaweed beds that sustain life on rocky shores. Check out the open access paper here: Threshold effects of relative sea-level change in intertidal ecosystems The 7.8 Mw Kaikōura earthquake affected a large section of the South Island’s east coast and led to a major re-assembly of ecological communities and coastal resource use. To understand the drivers of change and recovery in nearshore ecosystems, we quantified the variation in sea-level… Read More

Subtidal research

Robyn Dunmore and PhD student Dan Crossett from the Cawthron Institute have been tracking recovery in the nearshore subtidal zone. This has involved largescale surveys and experiments in the field and lab. They found that initially, there was clear disturbance to areas with medium to high uplift, especially around Waipapa Bay but also including areas like Ward, Wharanui and Okiwi Bay. Bare rock had been uplifted through sand and gravel, and shifts in sand and gravelinto seaweed habitats had also occurred. More recently, they observed some declines in large brown algae across… Read More

Remote sensing coastal recovery using drones

Over the last summer our drone survey team was busy optimising methods for measuring change in the coastal environment change. We now have a comprehensive set of 3D models and imagery from 30+ field sites. Advantages of drone technologies include the ability to cover more ground and a greater range of habitats than we can manage in ground-based surveys alone, yet the resolution of these methods is impressive. Each model covers several hundred metres of coast and the size of each pixel is < 1 cm on the ground! We are using… Read More

Lab studies on seaweed recovery

Following on from Recover issue 4, Dan Crossett and Robyn Dunmore from the Cawthron Institute have had some interesting results from lab experiments set up to test the effects of temperature, turbidity and light on juvenile large brown seaweed growth and survival. We found distinct differences in species’ early life stage responses. Landsburgia quercifolia was more tolerantof a wider range of conditions, with similar growth and survival across treatments. In contrast, Durvillaea antarctica (rimurapa or bull kelp) was the least tolerant and was strongly affected by increases in temperature and turbidity, with… Read More

Kelp and seaweed recovery

In the summer of 2019 NIWA and the University of Canterbury completed aerial drone surveys of many sites along the Kaikōura coast to examine the survival of vulnerable kelp species such as bull kelp (Durvillaea spp). This included testing the relative accuracy of readily available “RGB” cameras, and enhanced spectral cameras (multispectral cameras). This research revealed that both RGB and multispectral cameras can be used effectively for mapping broad scale distribution of marine vegetation (i.e., kelp), but multispectral cameras can be used to examine species biodiversity at higher taxonomic resolution. NIWA and… Read More

Seaweed recovery experiments

Before the earthquake, several reefs around the Kaikōura Peninsula and in the Cape Campbell area used to be covered by the seaweed Hormosira banksii (also known as Neptune’s necklace), but these lush algal forests were almost completely lost as a result of the uplift. It was shown by previous studies of MERG that these algal beds supported much of the biodiversity of intertidal reefs, which are now depauperate of other algae and small animals. We are now trying to aid the recovery of Hormosira by creating “oases” with shade and moisture in… Read More