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Kaikoura earthquake: Summary of impacts and changes in nearshore marine communities

July 2018

In book: Shakey Shores- Coastal impacts & responses to the 2016 Kaikoura earthquakes
Publisher: New Zealand Coastal Society

Authors:

David R. Schiel

University of Canterbury

Shawn Gerrity

University of Canterbury

Tommaso Alestra

Boffa Miskell Ltd

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The magnitude 7.8 Kaikoura earthquake of November 2016 impacted over 100 km of coastline, lifting rocky reef by up to 6 m. These events exposed vast areas of intertidal and subtidal rocky reef with dramatic effects to the habitat-forming kelp and fucoid species, and invertebrate species, including the highly valued paua. In this special issue we describe the consequences to the functioning and recovery of rocky reef ecosystems.

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Citation:

Schiel, D. R. et al. (2018). Kaikōura earthquake: Summary o1f impacts and changes in nearshore marine

communities. In (Hendlass, C. Borrero, J., Neale, D., and Shand, T. (eds). Shaky Shores: coastal impacts &

responses to the 2016 Kaikōura earthquakes. New Zealand Coastal Society, Special Publication 3, 2018, 44pp.

Habitat cascades destroyed in the Kaikoura earthquake

Conference Paper

Jan 2016

Alfonso Siciliano

Earthquake-driven destruction of an intertidal habitat cascade

Article

Feb 2020
AQUAT BOT

Large scale disturbances associated with anthropogenic activities or natural disasters can destroy primary habitat-forming species like corals, seagrasses and seaweeds. However, little research has documented if and on how large-scale disturbances affect secondary habitat formers, such as epiphytes and small animals that depend on biogenic habitats. Here we quantified changes in the abundance of both primary and secondary habitat-forming seaweeds as well as seaweed-associated invertebrates before and after a 7.8 Mw earthquake that uplifted four intertidal reef platforms by 0.5-0.8 m on the Kaikōura coastline in New Zealand. We found that the dominant primary (Hormosira banksii and three Cystophora species) and secondary (obligate and facultative epiphytes) habitat-forming seaweeds were all decimated and that mobile seaweed-associated animals were significantly less abundant (per gram of seaweed biomass) after the earthquake. Importantly, epiphytes became functionally extinct after the earthquake, as less than 0.1% of the populations survived, whereas primary habitat formers survived in suitable microhabitats, like water covered tide-pools and tidal channels. Based on these results we also discuss possible cascading ecosystem effects and future scenarios for natural recovery vs. active restoration that could speed up the recovery of habitat-forming species on degraded reefs.

Local Extinction of Bull Kelp (Durvillaea spp.) Due to a Marine Heatwave

Article

Full-text available

Mar 2019

Detailed research has documented gradual changes to biological communities attributed to increases in global average temperatures. However, localized and abrupt temperature anomalies associated with heatwaves may cause more rapid biological changes. We analyzed temperature data from the South Island of New Zealand and investigated whether the hot summer of 2017/18 affected species of bull kelp, Durvillaea antarctica, D. poha, and D. willana. Durvillaea spp. are large iconic seaweeds that inhabit the low intertidal zone of exposed coastlines, where they underpin biodiversity and ecosystem functioning. Sea surface temperatures (SST) during the summer of 2017/18 included the strongest marine heatwaves recorded in 38 years of existing oceanic satellite data for this region. Air temperatures were also high, and, coupled with small wave heights, resulted in strong desiccation stress during daytime low tides. Before-After analysis of drone images of four reef platforms (42, 42, 44, and 45°S) was used to evaluate changes to bull kelp over the hot summer. Bull kelp loss varied among species and reefs, with the greatest (100%) loss of D. poha at Pile Bay in Lyttelton Harbor (44°S). In Pile Bay, SST exceeded 23°C and air temperatures exceeded 30°C, while Durvillaea was exposed for up to 3 h per day during low tide. Follow-up surveys showed that all bull kelps were eliminated from Pile Bay, and from all reefs within and immediately outside of Lyttelton Harbor. Following the localized extinction of bull kelp in Pile Bay, the invasive kelp Undaria pinnatifida recruited in high densities (average of 120 m⁻²). We conclude that bull kelps are likely to experience additional mortalities in the future because heatwaves are predicted to increase in magnitude and durations. Losses of the endemic D. poha are particularly concerning due to its narrow distributional range.

Rapid population recovery of a foundation species from experimental small-scale harvesting

Article

Jun 2025
J PHYCOL

Ecological stability is central to understanding how disturbances challenge the persistence of populations and communities through time, especially when key species are impacted. The bull kelp Durvillaea incurvata is a foundation, habitat-forming species that provides food and shelter for various species and supports the livelihoods of human communities along the Chilean coast. Harvesting of Durvillaea has raised concerns about the long-term viability of its populations, but the stability responses of Durvillaea to anthropogenic disturbances remain unclear. Here, we conducted a manipulative experiment in which we removed, once, all Durvillaea individuals from two sites in southern Chile to simulate the spatial scale of harvesting and to describe the population resilience and recovery following disturbance. In 1-m2 plots interspersed in matrices of dense Durvillaea stands, we removed fronds and holdfasts, a practice not typically developed by gatherers, testing an alternative harvesting strategy. For 25 months, we quantified Durvillaea recruitment, holdfast densities, percent cover, frond length and density, biomass, and population size structure. All metrics completely recovered within 5–7 months across sites. The removal of Durvillaea did not have a significant impact on recruitment, which was constant during the experiment. The small spatial scale of the disturbances, the constant recruits supplied by the surrounding bull kelp matrix, and the removal of holdfasts that released settlement substratum allowed for the strong stability responses in these populations. Therefore, harvesting strategies that promote spatial heterogeneity, such as the removal of whole individuals at a small spatial scale, should be prioritized in management schemes of natural seaweed stands.

Shifts in foundation species dominance and altered interaction networks after compounding seismic uplift and extreme marine heatwaves

Article

Full-text available

Sep 2024
MAR ENVIRON RES

The consequences of uplift on wave transformation across a shore platform, Kaikōura, New Zealand

Article

Aug 2022
MAR GEOL

Co-seismic uplift of the Kaikōura Peninsula in 2016 provided a rare opportunity to examine changes in wave hydrodynamics on a tectonically active rock coast comprised of a microtidal shore platform and marine terraces. We compared pre-uplift wave conditions measured in February 2007 with post-uplift conditions at the same site in December-2019 following +0.95 m of vertical displacement. Shore platform gradient was not affected by uplift, but the earthquake raised the seafloor, resulting in a nearly 40% decline in incident onshore energy under comparable offshore conditions. Uplift also resulted in a 50% reduction in the intertidal width of the shore platform, which decreased the amount of gravity wave (>0.05 Hz) energy attenuation. In pre-uplift conditions, energy in the swell (0.05–0.125 Hz) and wind (0.125–0.33) wave spectral frequencies at the most landward sensor contributed 28% of total energy, whereas after uplift the most landward sensor received 49% of total energy from these frequencies. Most of the remaining energy detected on the innermost sensors was from infragravity spectral frequencies, with 45% post-uplift compared to 71% pre-uplift. Co-seismic uplift has reorganised the shore platform and marine terrace sequence, and the associated wave hydrodynamics: about half of the pre-uplift shore platform is now disconnected from wave erosion under calm swell conditions. Uplift has reduced wave inundation on the shore platform and when combined with a reduction in incipient wave energy, suggests less vulnerability to wave erosion so that the uplifted surface may be preserved as a new marine terrace.

Seashore uplift and the distribution of the bull kelp Durvillaea willana Lindauer in New Zealand

Article

Oct 2019

Cameron H. Hay

The endemic bull kelp Durvillaea willana Lindauer grows on South and Stewart/Rakiura Islands, with a small North Island population on the northern Wairarapa coast. Drawing on field observations, the distribution of this species is mapped. Within its biogeographic range, there are three lengthy tracts of rocky shore where the kelp is conspicuously absent. These distributional gaps are: Wellington’s south coast (despite proximity to populations on the South Island side of Cook Strait), the southern and central Wairarapa Coast, and in South Westland. Theorising that these gaps have been caused by earthquake-driven coastal uplift, this paper examines the effects on Durvillaea species of a 7.8 Mw earthquake in 2016, which raised around 100 km of seashore along the Kaikōura coast, plus the historical evidence of uplift along the Akatore Fault, south of Dunedin. This evidence suggests that the requirements for such local extinctions are that the uplift is consistently higher than the kelp’s vertical range, and that it occurs along an entire rocky coastal tract flanked by barriers to recolonisation such as long beaches or deep ocean–major obstacles to a non-buoyant kelp with poor dispersive ability.

Effects of sediment on early life history stages of habitat-dominating fucoid algae

Article

Jul 2019
J EXP MAR BIOL ECOL

The effects of sediment on settlement and early post-settlement survival of habitat-dominating fucoid algae have not been extensively investigated. Two separate experiments tested whether different size-fractions, abundances and types of sediment differentially affect the attachment of Hormosira banksii and Cystophora torulosa zygotes under laboratory conditions, and whether alteration of the sediment environment differentially affects early post-settlement survival of fucoid zygotes placed into the natural environment. In the laboratory, an average of c. 59% of Hormosira zygotes were able to attach to primary substratum in the presence of sparse sand and silt, compared to 28% (silt) and 39% (sand) of Cystophora zygotes. In the presence of dense sand or silt, <8% of either species attached to primary substratum, with the great majority of zygotes of both species attaching to sediment grains. In the field, Hormosira zygotes across three treatments survived for the entire two week experimental period, whereas no Cystophora zygotes survived beyond 8 days. For both species there was a gradient of survival across treatments, from the poorest survival on bare rock, slightly better survival in coralline turf that contained sediments, and greater survival in coralline turf with the sediment removed, although there were significant interactive effects of treatment and time. After two weeks, an average of 22% of Hormosira zygotes survived on bare rock, around 38% on coralline turf with sediment, and 40% on coralline turf minus sediment, but with high variation in the treatments. On day 5 of the field experiments, when zygotes of both species remained across treatments, there were significant differences between species and between treatments which mirrored results across the whole experiment. Overall, the experiment showed that the sediment environment influenced both the attachment of fucoid zygotes and early post-settlement survival. The experiments highlighted key differences between species in their method of attachment and subsequent interactions within the abiotic environment, with the larger stickier zygotes of Cystophora more readily attaching to sediment grains, and the less sticky Hormosira zygotes often rolling through the sediments and attaching to the primary substratum. These early life history characteristics of key species and their interaction with those of microsites in which they settle clearly have importance to the replenishment and maintenance of populations.

ResearchGate has not been able to resolve any references for this publication.

Kaikoura earthquake: Summary of impacts and changes in nearshore marine communities

Abstract

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