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
New Report on beach recovery in Marlborough
A new report covers some of our ongoing disaster recovery work on the Kaikōura and Marlborough coasts. It responds to a request from Marlborough District Council (MDC) for information on the coastal environment, with a particular focus on supporting the development of a bylaw to address changes in recreational use patterns that have occurred since the Kaikōura earthquake. In the report, we present a selection of information from our earthquake recovery research that has a focus on understanding the impacts and ongoing processes of change. Major impacts of the natural disaster are associated… 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
Whitebait spawning sites in Kaikōura’s rivers
Early in 2019 we started work to fill a knowledge gap about whitebait in streams and rivers along the Kaikōura coast. For īnanga, which makes up the bulk of the whitebait catch, the spawning grounds are usually found close to the coast near the river mouths. Knowing where they are is useful for recovery planning in the same areas post-earthquake as well as for restoration projects in local waterways. Our survey programme started with fish trapping to find out which species were living in which rivers, after which we selected waterways that… Read More
Recover in the news
Check out a few recent views from our UAV (drone) surveys of reefs uplifted by the Kaikōura earthquake and read more in the recent Stuff article here It was also great to see some international interest in this work.See a recent article in a German magazine focussing on New Zealand here
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
How much of the coast was uplifted by how much?
Although Covid19 set back some of our planned fieldwork, we put the lockdown period to good use to characterise some of the core earthquake impacts on the coast. One key questions is ‘how much of the coast was uplifted and by how much?’. Knowing this helps us to extrapolate the results from small-scale field surveys to the wider coast, which in turn is the best method for gauging the extent of impacts and how the recovery is looking overall. Being able to report the results as the ‘length of coastline’ affected is… Read More
Young pāua growing well
Our work monitoring the juvenile pāua around Kaikōura has shown encouraging signs of recovery of this hardhit population. Wild pāua tagged a year ago have had excellent growth rates and survival. They’re quickly advancing through the size classes and will soon migrate to deeper waters and join the adult spawning groups, a key step in recovery. The abundance of pāua at our sites is increasing significantly through time, and we are seeing much higher numbers than we did in theearly days after the earthquake. Hatchery-raised reseed pāua planted in 2018 by the… Read More
Whitebait hatching experiment with Environment Canterbury
Our discovery of whitebait spawning sites in Kaikōura streams (see Recover Issue 3) ended with a twist in Waikoau / Lyell Creek when we realised that the eggs were unlikely to hatch. Thanks to Pete Adams at Environment Canterbury we came up with an engineering experiment in the form of a temporary closure — the reverse of mechanical stream openings that are routinely used to alleviate flood waters backing up after natural river mouth closures. In this case we temporarily blocked the mouth with gravel to raise the water level around 40… 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
Beach birds: mapping hotspots for banded dotterels
Our beach birds study got underway this year on the uplifted Marlborough and Kaikōura coast beaches. In early December we completed a baseline survey of where Banded Dotterel nesting grounds are found, all the way from Oaro in the south to Marfells Beach in the north. That was a lot of walking for our team of three! The beach birds study aims to identify the most important nesting locations and assess interactions with human activities along the earthquake-affected coast. Knowledge of these sites fills a gap for coastal planning, especially where the… 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
Paua population monitoring
Monitoring of intertidal paua populations along the Kaikōura coastline has yielded some interesting findings. It looks like overall the hot summer hasn’t adversely affected the vulnerable juveniles, who seem to be growing more quickly than we expected. Recaptured seed paua, identified by the blue shell material at their apex from hatchery diet, have shown phenomenal growth rates since being seeded a year ago. Paua that grow quickly will reach predator release sooner, the size at which they are less likely to be eaten. The natural population is now dominated by larger paua… Read More
Juvenile paua research
We have had a busy past few months doing some experimental fieldwork. This included a pilot study looking at some semi-artificial reef installations to see if juvenile paua would use some rock-filled cages for cover/shelter. These were designed to provide optimal habitat for wild paua, and possibly to use as deployment structures for paua reseeding efforts. In just a couple weeks we found that all sorts of animals had voluntarily crawled into the cages, including plenty of black and yellow paua aged 1-2 years. We were pretty excited at this response, which… Read More
Overview of earthquake impacts
Initial Impacts Soon after the earthquake MERG began re-surveying our long-term research sites that span the coast. Many of these sites have been monitored for over 20 years. These surveys gave us a good understanding of the immediate impacts on coastal habitats and species. This work also provided a great foundation for our post-earthquake research. The following sections provide a snapshot of some important changes that resulted from the Kaikōura earthquake. Coastal fishes & invertebrates By chance, the earthquake happened to coincide with a high tide. This meant increased devastation to marine… Read More
What is RECOVER?
RECOVER is collecting data on recovery of the natural environment with a focus on the short to mid-term prospects for key species and habitats along the coast. We are particularly interested in understanding the nature of earthquake impacts, detecting barriers to a full recovery, and investigating how long it might take. Why?RECOVER is aimed at helping the coastal environment return to a ‘new-normal’ following the earthquakes. As we already know the earthquakes have caused massive changes, RECOVER focuses more on what happens next. Some main themes of the project include predicting the… Read More
