Article

The Kaikōura earthquake in southern New Zealand: Loss of connectivity of marine communities and the necessity of a cross‐ecosystem perspective

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Abstract

• The Mw 7.8 earthquake that struck the north‐east coast of the South Island of New Zealand in November 2016 caused extensive upheaval, of up to 6 m, over 110 km of coastline. Intertidal habitats were greatly affected with extensive die‐off of algal communities, high mortalities of benthic invertebrates, and greatly reduced ecosystem functioning, such as primary productivity. Only isolated pockets of key species remained in these areas, many of which were within protected areas around Kaikōura. • The loss of key species of algae and invertebrates fragmented marine populations and compromised connectivity and recovery processes because of the large dispersal distances needed to replenish populations. Severe sedimentation from terrestrial slips and erosion of newly exposed sedimentary rock compromised settlement and recruitment processes of marine species at many sites, even if distant propagules should arrive. • The combination of habitat disruption, loss of species and their functioning, and impacts on commercial fisheries, especially of abalone (Haliotis iris), requires multiple perspectives on recovery dynamics. • This paper describes these effects and discusses implications for the recovery of coastal ecosystems that include the essential involvement of mana whenua (indigenous Māori people), fishers, and the wider community, which suffered concomitant economic, recreational, and cultural impacts. These community perspectives will underpin the protection of surviving remnants of intertidal marine populations, the potential use of restoration techniques, and ultimately a successful socio‐ecological recovery.

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... This leads to conspicuous zonation and migration patterns (Cartwright & Williams, 2012;Takada, 1996;Williams & Morritt, 1995). For example, algae commonly experience burn-offs during hot and sunny days that coincide with summertime low tides (Harley & Paine, 2009;Keough & Quinn, 1998;Schiel et al., 2019), while some mobile invertebrates migrate seasonally, presumably to avoid abiotic stressors or access new foraging areas (Cartwright & Williams, 2012;Williams & Morritt, 1995). Although intertidal organisms are well adapted to the extreme variability inherent to their habitat, the rate at which temperature variability has been increasing due to climate change may outpace the ability of these organisms to adapt (Somero, 2002;Stillman, 2019). ...
... Although intertidal organisms are well adapted to the extreme variability inherent to their habitat, the rate at which temperature variability has been increasing due to climate change may outpace the ability of these organisms to adapt (Somero, 2002;Stillman, 2019). This has led to a substantial increase in the number of catastrophic mortality events, mainly where midday low tides have corresponded with extremely high temperatures (Harley, 2008;Hesketh & Harley, 2023;Jones et al., 2010;Konisky et al., 2006;Raymond et al., 2022;Schiel et al., 2019;Thomsen et al., 2019). For example, mass mortalities of limpets and mussels were observed during a record-breaking spring heatwave in California, where survival was strongly correlated with substrate orientation (Harley, 2008). ...
... and exhibit homing behaviour to these favourable locations (Creese & Underwood, 1982;Gray & Hodgson, 1998;Underwood, 1977). This behavioural thermoregulation probably plays a significant role in the resilience of limpet populations against extreme heat events, which are becoming increasingly common in the intertidal zone (Harley, 2008;Hesketh & Harley, 2023;Jones et al., 2010;Raymond et al., 2022;Schiel et al., 2019). ...
Article
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Small‐scale spatial variation in temperature plays a key role in limiting the distribution of organisms in thermally heterogeneous environments. In the rocky intertidal zone, intra‐day temperature variation at small scales (cm–m) can easily exceed 30°C. To experimentally test the impact of this small‐scale temperature heterogeneity on the distribution of an ecologically important limpet species (Cellana denticulata), boulders on an intertidal rocky reef in New Zealand were rotated and small‐scale temperature variability and food availability were measured throughout 1 year. Small‐scale variability in thermal tolerance, heart rate and heat shock protein expression was also measured to relate in situ limpet distributions with environmental conditions. Temperature variability was measured using limpet bio‐mimics and HOBO pendant temperature loggers, while food availability (chlorophyll a concentration) was measured on in situ concrete fibreboard tiles. To measure limpet distributions, every tagged limpet on each of 18 boulders was followed from June 2021 to 2022. During each sampling, the location of each limpet, compass direction and slope of the surface that each limpet inhabited was measured. To test for physiological differences among limpets from each microhabitat, thermal tolerance and heat shock protein expression were measured in collected limpets; in situ heart rates and body temperatures were also measured sporadically on hot days. Maximum predicted body temperatures (36–39°C), heart rates and actual body temperatures were greatest on equatorial surfaces (i.e. surfaces facing the equator) whereas food availability was greatest on poleward‐facing surfaces. During summer, limpets moved towards surfaces that minimised their body temperatures and maximised food availability, namely vertical and poleward‐facing surfaces and undersides of boulders. Thermal tolerance, measured using Arrhenius breakpoint temperatures (mean ± SE: 34.7–35.8 ± 0.4–0.7°C) and flat line temperatures (36.2–37.4 ± 0.3–0.4°C), was similar among limpets facing different directions. Surprisingly, heat shock protein expression was relatively consistent throughout the year and among directions. Overall, limpet populations are resilient to thermal stress because they effectively use behavioural thermoregulation to exploit cooler microhabitats that also have greater food availability during summer. Read the free Plain Language Summary for this article on the Journal blog.
... With a shallow hypocentre of 15 km and many complex inshore and offshore faults, slips, vertical displacements, coastal uplifts of up to 6.5 m, and >2,000 aftershocks in only 3 days, four of which had magnitude >6 M w , these earthquakes directly affected c. 130 km coastline Hamling et al., 2017;Xu et al., 2018). Over the next few months, we observed extensive loss of habitat-forming seaweeds and slow-moving benthic invertebrates, with associated losses of primary productivity, biogenic habitat and altered food webs Schiel et al., 2019;Thomsen et al., 2020). A year later, over the austral summer of 2017/18, New Zealand experienced the strongest marine heatwave on record (Salinger et al., 2019(Salinger et al., , 2020. ...
... A year later, over the austral summer of 2017/18, New Zealand experienced the strongest marine heatwave on record (Salinger et al., 2019(Salinger et al., , 2020. This large-scale extreme marine event, coincided with high air temperatures, low tides and calm sea conditions (Salinger et al., 2020;, and had widespread effects such as high glacial melting, losses of habitat-forming seaweeds, and movement of fish into warm waters (Salinger et al., 2020;Schiel et al., 2019;Tait et al., 2021;. Following Hobday et al. (2018), this large-scale temperature anomaly was named the "Tasman Sea 2017/18 marine heatwave" Salinger et al., 2019). ...
... The mid band was a bright "green" because it was dominated by the ephemeral green algae Ulva spp. (Figure 1b,g) Schiel et al., 2019). ...
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Aim Ecologists traditionally study how contemporary local processes, such as biological interactions and physical stressors, affect the distribution and abundance of organisms. By comparison, biogeographers study the distribution of the same organisms, but focus on historic, larger-scale processes that can cause mass mortalities, such as earthquakes. Here we document cascading effects of rare biogeographical (seismic) and more common ecological (temperature-related) processes on the distribution and abundances of coastal foundation species. Location Intertidal wave-exposed rocky reefs around Kaikōura, New Zealand, dominated by large, long-lived, and iconic southern bull kelps (Durvillaea antarctica and Durvillaea willana). Methods In November 2016, a 7.8 Mw earthquake uplifted the coastline around Kaikōura by up to 2 m, and a year later the region experienced the hottest summer on record. Extensive sampling of intertidal communities over 15 km coastline were done shortly after the earthquake and heatwaves and 4 years after the earthquake. Results Durvillaea lost 75% of its canopy to uplift and the heatwaves reduced canopies that had survived the uplift by an additional 35%. The survey done 4 years after the earthquake showed that Durvillaea had not recovered and that the intertidal zone in many places now was dominated by small turfs and foliose seaweed. Main conclusions Cascading impacts from seismic uplift and heatwaves have destroyed populations of Durvillaea around Kaikōura. Surviving smaller and sparser Durvillaea patches will likely compromise capacity for self-replacement and lower resilience to future stressors. These results are discussed in a global biogeographical-ecological context of seismic activity and extreme heatwaves and highlight that these events, which are not particularly rare in a geological context, may have common long-lasting ecological legacies.
... It also occurs primarily on the most wave-exposed rocky reef habitats. Not only has this species been greatly reduced by marine heat waves that caused additional localised ex-tinctions [1], but large-scale coastal uplift from a 7.8 magnitude earthquake [13][14][15] severely affected populations, causing complete loss across uplifted rocky reef habitats [16]. These impacts occurred over 130 km of a sparsely inhabited, very heterogenous coastline featuring platforms, rocky outcrops and boulder fields that made in-situ sampling difficult or impossible in many places. ...
... Perhaps first and foremost is the very highly localised and patchy diversity evident in nearshore marine systems [24]. In the focal area, over 200 species have been recorded, and there is an average of around 20 species per square meter in the lower intertidal zone [16]. The varying sizes of individuals of each species, ranging from sub-cm to m, and the layering of their canopies [25] render them difficult or impossible to see in their entirety from above. ...
... This paper outlines the utility, limitations and caveats to the use of drones in monitoring vulnerable marine rocky reef habitats and proposes a consistent standardised approach to the capture of imagery and validation samples to ensure that such imagery meets the requirements of agencies tasked with management and conservation of vulnerable or threatened species. We use two examples to illustrate the utility of drones for conservation management: (1) The 2016 Kaikōura earthquake, which shifted relative sea levels, caused mass mortality of key habitat-forming macroalgae (especially of the southern bull kelp species), and shifted assemblages to ephemeral red and green algae [16,32]; and (2) highly wave-exposed rocky reef platforms located on the West Coast of New Zealand. ...
Article
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Coastal marine ecosystems are under stress, yet actionable information about the cumulative effects of human impacts has eluded ecologists. Habitat-forming seaweeds in temperate regions provide myriad irreplaceable ecosystem services, but they are increasingly at risk of local and regional extinction from extreme climatic events and the cumulative impacts of land-use change and extractive activities. Informing appropriate management strategies to reduce the impacts of stressors requires comprehensive knowledge of species diversity, abundance and distributions. Remote sensing undoubtedly provides answers, but collecting imagery at appropriate resolution and spatial extent, and then accurately and precisely validating these datasets is not straightforward. Comprehensive and long-running monitoring of rocky reefs exist globally but are often limited to a small subset of reef platforms readily accessible to in-situ studies. Key vulnerable habitat-forming seaweeds are often not well-assessed by traditional in-situ methods, nor are they well-captured by passive remote sensing by satellites. Here we describe the utility of drone-based methods for monitoring and detecting key rocky intertidal habitat types, the limitations and caveats of these methods , and suggest a standardised workflow for achieving consistent results that will fulfill the needs of managers for conservation efforts.
... This is a high-energy coastline with near-constant oceanic swells, generally turbid inshore waters, and rocky reefs and boulder fields interspersed with sand and gravel. The immediate effect of the earthquake on nearshore marine species was high mortality of algal beds and their resident species (Schiel et al. 2019). There were 3 potentially negative effects on pāua populations. ...
... There were 3 potentially negative effects on pāua populations. The most evident was in higher uplift areas, where entire reef complexes were permanently lifted above the high water mark, causing mortality of adult pāua, as tens of thousands were stranded at many sites (Schiel et al. 2019). The second potential impact was failure of post-earthquake recruitment because of reduced adult populations or sublethal effects on surviving pāua. ...
... Unfortunately, very little quantitative data exist in the study area for pre-earthquake pāua populations, habitat structure and distribution of juvenile habitat. However, at one site with 0.2 m of uplift for which pre-and post-earthquake data were available, an estimated 45% of juvenile habitat was lost by being pushed upwards into a harsher tidal zone (Schiel et al. 2019) and, across the region, around 21% of commercially fished reefs were destroyed through uplift or burial by sediment (P. Neubauer unpubl.). ...
Article
The 2016 Mw7.8 Kaikōura earthquake lifted 140km of coastline on New Zealand’s South Island by up to 6.4m. This caused extensive mortality and destruction of habitat critical for early life stages of blackfoot abalone, Haliotis iris (called pāua), a species of cultural and commercial importance. The fishery for pāua was closed, at considerable financial loss to local communities. This study determined the extent to which habitats and populations of pāua survived along the coastline. With aerial imaging, the coast was categorised into broad habitats at a 10m scale. This was used to select areas for in situ assessments of pāua populations and specific habitat features at 26 sites over 1.5 years. We quantified key habitat features to identify correlates and potential drivers of pāua abundance and distribution. We found that despite extensive habitat degradation from uplift, erosion and sedimentation, abundant pāua in size classes <30mm shell length indicated successful settlement and juvenile recruitment had occurred soon after the earthquake. Pāua up to 170mm shell length had also survived in shallow habitats. A generalized linear mixed model showed that pāua were negatively influenced by the degree of uplift, and positively associated with the cover of unconsolidated layered rocks. Juvenile pāua (<85mm) abundance was greatest at sites with <2.5m of uplift. There was further recruitment 1.5 years post-earthquake and evidence of good growth of the previous year’s cohort. Despite major disruption to this coastline, there appears to be very good potential for recovery of pāua and the fishery.
... Recently, the habitat cascade concept has highlighted that primary habitat-forming organisms also promote sequential habitat formation that can increase biodiversity through the provision of more or novel niche space and supplies of food Gribben et al., 2019). Such primary habitat-forming organisms have been decimated in many parts of the world by anthropogenic activities (Halpern et al., 2008) and, occasionally, natural mega-disturbances including earthquakes and volcanic activity (Bodin and Klinger, 1986;Castilla, 1988;Castilla and Oliva, 1990;Castilla et al., 2010;Williams et al., 2010;Schiel et al., 2019). However, the implications of the combined loss of both primary and sequential habitat formers following severe disturbances are poorly understood because most studies have only focused on losses of primary habitat formers (Halpern et al., 2008). ...
... Building a framework to predict impacts on shallow coastal systems from mega-disturbances is further complicated because underpinning processes operate over very different spatio-temporal scales. For example, following instantaneous uplifts, smaller scale processes like herbivory, competition, light availability and desiccation stress are dramatically altered in concert with larger scale processes like limited propagule pressure and disrupted population connectivity, (Castilla and Oliva, 1990;Waters et al., 2013;Schiel et al., 2019), making it challenging to predict survival and recovery trajectories. Nevertheless, case studies that document ecological impacts from mega-disturbances will increase our collective knowledge about what types of organisms are particularly sensitive (or resilient) and whether micro-habitats can modify effects. ...
... As a result, this region will likely support fewer and smaller populations of Hormosira, Notheia and C. torulosa in the future. Another issue facing the Kaikōura coastline is accelerated erosion of newly uplifted rock, and the subsequent enhanced sediment deposition in the intertidal zone (Schiel et al., , 2019, resulting in either bare (and continually eroding) rock or gravel substrates at possible colonisation sites. Elsewhere along the uplifted coast, small green ephemeral seaweeds (Ulva spp.) have become abundant in lower to mid zones (Schiel et al., , 2019 and these seaweeds may compete for space with recolonizing primary habitat formers, at least in the short term (Sousa, 1979). ...
... Recently, the habitat-cascade concept has highlighted that primary habitatforming organisms also promote sequential habitat formation that can increase biodiversity through the provision of more or novel niche space and supplies of food (Thomsen et al., 2018;Gribben et al., 2019). Such primary habitat-forming organisms have been decimated in many parts of the world by anthropogenic activities (Halpern et al., 2008) and, occasionally, natural mega-disturbances including earthquakes and volcanic activity (Bodin and Klinger, 1986;Castilla, 1988;Castilla and Oliva, 1990;Castilla et al., 2010;Williams et al., 2010;Schiel et al., 2019). However, the implications of the combined loss of both primary and sequential habitat formers following severe disturbances are poorly understood because most studies have only focused on losses of primary habitat formers (Halpern et al., 2008). ...
... Building a framework to predict impacts on shallow coastal systems from mega-disturbances is further complicated because underpinning processes operate over very different spatio-temporal scales. For example, following instantaneous uplifts, smaller scale processes like herbivory, competition, light availability and desiccation stress are dramatically altered in concert with larger scale processes like limited propagule pressure and disrupted population connectivity, (Castilla and Oliva, 1990;Waters et al., 2013;Schiel et al., 2019), making it challenging to predict survival and recovery trajectories. Nevertheless, case studies that document ecological impacts from mega-disturbances will increase our collective knowledge about what types of organisms are particularly sensitive (or resilient) and whether micro-habitats can modify effects. ...
... As a result, this region will likely support fewer and smaller populations of Hormosira, Notheia and C. torulosa in the future. Another issue facing the Kaikōura coastline is accelerated erosion of newly uplifted rock, and the subsequent enhanced sediment deposition in the intertidal zone (Schiel et al., 2018;Schiel et al., 2019), resulting in either bare (and continually eroding) rock or gravel substrates at possible colonisation sites. Elsewhere along the uplifted coast, small green ephemeral seaweeds (Ulva spp.) have become abundant in lower to mid zones (Schiel et al., 2018;Schiel et al., 2019) and these seaweeds may compete for space with recolonizing primary habitat formers, at least in the short term (Sousa, 1979). ...
Article
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.
... The primary foundation species on intertidal wave-exposed rocky reefs are typically a few species of large canopy-forming kelp (order Laminariales) and/or fucoids (order Fucales) that are competitively dominant under prevailing environmental conditions (Steneck et al., 2002;Schiel and Foster 2006;Wernberg et al., 2019;Thomsen et al., 2024). These reefs, and their primary foundation species, are frequently exposed to natural disturbances, particularly from storms (Sousa 1984;Denny 1985;Chapman and Johnson 1990;Dayton et al., 1992;Underwood 1998), but can also be disturbed by rare tsunamis and earthquakes (Castilla 1988;Muraoka et al., 2017;Schiel et al. 2019Schiel et al. , 2021Thomsen et al., 2021). In addition, rocky reefs are increasingly disturbed by human related activities, including elevated nutrients, sediments, and coastal darkening (Airoldi 2003;Firth et al., 2016;Opdal et al., 2019), species invasions and overgrazing (Grosholz 2002;Filbee-Dexter and Scheibling 2014), and stronger, longer, and more frequent marine heatwaves (MHWs) (Thoral et al., 2022;Smith et al., 2023;Wernberg et al., 2024). ...
... Second, D. antarctica is only reproductive from late autumn to early spring leaving a short window to produce propagules (Naylor 1953;Hay 1979). Third, propagules are heavy and sticky, so dispersal is most effective within a few meters from parent plants (Taylor and Schiel 2003;Dunmore 2006;Schiel and Foster 2006;Schiel et al., 2019). Recolonisation of large unpopulated reef sections from spores is therefore unlikely (Taylor and Schiel 2003). ...
... The associated fault ruptures were among the most complex ever recorded [27][28][29] and manifested as a highly variable pattern of ground-level displacement but mostly in the direction of uplift [30]. These physical impacts led to widespread reassembly of ecological communities on rocky shorelines [31][32][33]. Associated social and economic effects included new landscape configurations altering access to the coast, and the closure of commercial fisheries and recreational harvesting of seaweeds and shellfish [34,35]. ...
... Once populations of large algae are removed, recovery can be slow where reproductive adults become widely separated due to connectivity effects between suitable habitat for re-colonisation and the remaining recruitment sources [32]. A wide range of processes are likely hindering recovery in the post-earthquake landscape, including the now widely dispersed adult populations, the relatively short distance of propagule dispersal (usually only tens of meters), and limited ability of drifting detached reproductive algae to reach sites [37]. ...
Article
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Widespread mortality of intertidal biota was observed following the 7.8 Mw Kaikoura earthquake in November 2016. To understand drivers of change and recovery in nearshore ecosystems, we quantified the variation in relative sea-level changes caused by tectonic uplift and evaluated their relationships with ecological impacts with a view to establishing the minimum threshold and overall extent of the major effects on rocky shores. Vertical displacement of contiguous 50 m shoreline sections was assessed using comparable LiDAR data to address initial and potential ongoing change across a 100 km study area. Co-seismic uplift accounted for the majority of relative sea-level change at most locations. Only small changes were detected beyond the initial earthquake event, but they included the weathering of reef platforms and accumulation of mobile gravels that continue to shape the coast. Intertidal vegetation losses were evident in equivalent intertidal zones at all uplifted sites despite considerable variation in the vertical displacement they experienced. Nine of ten uplifted sites suffered severe (>80%) loss in habitat-forming algae and included the lowest uplift values (0.6 m). These results show a functional threshold of c.1/4 of the tidal range above which major impacts were sustained. Evidently, compensatory recovery has not occurred—but more notably, previously subtidal algae that were uplifted into the low intertidal zone where they ought to persist (but did not) suggests additional post-disturbance adversities that have contributed to the overall effect. Continuing research will investigate differences in recovery trajectories across the affected area to identify factors and processes that will lead to the regeneration of ecosystems and resources.
... The onshore portion of the Akatore fault has, in the past millennium, uplifted ~30 km of the coast by 2-3 m above the high-tide zone (Litchfield & Norris, 2000). Recent ecological studies of tectonically active shores elsewhere have shown that uplift events approaching this magnitude are sufficient to extirpate habitat-forming macroalgae and their associated epibiota, thus creating empty intertidal habitats for recolonization Jaramillo et al., 2012;Schiel et al., 2019;Thomsen et al., 2020Thomsen et al., , 2021. In the case of the Akatore fault, radiocarbon dating has constrained the most recent rupture event to 800-1000 years BP (Craw et al., 2021;Litchfield & Norris, 2000). ...
... Phylogeographic model selection using the narrow time prior showed higher power in distinguishing between different recolonization routes (Table S5). (Castilla, 1988;Clark et al., 2017;Ortega et al., 2014;Schiel et al., 2019). As a case in point, New Zealand's 2016 Kaikoura earthquake ( Figure 1a,c) led to major changes in the configuration of rocky reefs, and dramatic reductions in populations of numerous intertidal habitat-forming seaweeds and associated invertebrates (Thomsen et al., 2020. ...
Preprint
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The elimination of lower trophic levels following severe habitat disturbance can trigger new community assembly processes. However, little is known about how past habitat disturbances have affected codependent evolution of trophically-linked and closely interacting taxa. Using genome-wide analysis of a macroalgal community affected by ancient catastrophic coastal uplift, we track the ecological dynamics of past co-dispersal and co-diversification among obligate interacting taxa. Our study reveals rapid and concerted reassembly of an intertidal community following disturbance. Specifically, hierarchical co-demographic analyses of multispecies genomic data support synchronous expansions of four strictly intertidal species in the wake of tectonic disturbance. These data show that tight algal-epifaunal links underpin parallel demographic responses across distinct trophic levels. These results highlight that high-resolution comparative genomic data can elucidate the strength of obligate ecological interactions, and the evolutionary dynamics of past co-dispersal and co-diversification in post-disturbance communities.
... The earthquake caused over 20 000 landslides that delivered mass amounts of sediment to river catchments (Massey et al., 2018). Fine sediment has been carried to the sea and has smothered and suffocated tidal to intertidal shallow-marine ecosystems (Schiel et al., 2019). High sedimentation coupled with coastal uplift has caused the biogeomorphology of the region to change dramatically following the earthquake (Schiel et al., 2019). ...
... Fine sediment has been carried to the sea and has smothered and suffocated tidal to intertidal shallow-marine ecosystems (Schiel et al., 2019). High sedimentation coupled with coastal uplift has caused the biogeomorphology of the region to change dramatically following the earthquake (Schiel et al., 2019). The ongoing stability of marine species has the potential to indicate sedimentation rates and the effect that the geomorphology of the area has on marine populations. ...
Article
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Mixed-method bicultural research in Aotearoa New Zealand, including the weaving of Indigenous and other knowledge, is emerging within many academic disciplines. However, mātauranga Māori (the knowledge, culture, values, and world view of the Indigenous peoples of Aotearoa New Zealand) and Te Ao Māori (the Māori world) is poorly represented within geomorphological investigations. Here, we review international efforts to include Indigenous knowledge in geologic and geomorphic studies and provide an overview of the current state of mātauranga Māori within research endeavours in Aotearoa New Zealand. We review three theoretical frameworks (i.e. methodologies) for including mātauranga Māori in research projects and three models (i.e. methods) for including Māori values within research. We identify direct benefits to geomorphology and discuss how these frameworks and models can be adapted for use with Indigenous knowledge systems outside of Aotearoa New Zealand. The aim of this review is to encourage geomorphologists around the world to engage with local Indigenous peoples to develop new approaches to geomorphic research. In Aotearoa New Zealand, we hope to inspire geomorphologists to embark on research journeys in genuine partnership with Māori that promote toitū te mātauranga – the enduring protection, promotion and respect of mātauranga Māori.
... Our demographic modelling supports the geologically derived hypothesis [26] that the Akatore Fault rupture event around 800 years ago caused widespread extirpation of intertidal kelps from the area (electronic supplementary material, table S8), consistent with direct observations of recent uplift events elsewhere [23,36]. Durvillaea kelps are habitat-forming species, hosting diverse epibiotic taxa, and thus their re-establishment can play an important role in post-disturbance recovery of southern rocky intertidal ecosystems [36]. ...
... Our demographic modelling supports the geologically derived hypothesis [26] that the Akatore Fault rupture event around 800 years ago caused widespread extirpation of intertidal kelps from the area (electronic supplementary material, table S8), consistent with direct observations of recent uplift events elsewhere [23,36]. Durvillaea kelps are habitat-forming species, hosting diverse epibiotic taxa, and thus their re-establishment can play an important role in post-disturbance recovery of southern rocky intertidal ecosystems [36]. Demographic modelling suggests that D. poha started to colonize the uplifted habitats earlier than D. antarctica, but took longer to expand its range than D. antarctica ( figure 3; electronic supplementary material, table S8). ...
Article
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Theory suggests that catastrophic earth-history events can drive rapid biological evolution, but empirical evidence for such processes is scarce. Destructive geological events such as earthquakes can represent large-scale natural experiments for inferring such evolutionary processes. We capitalized on a major prehistoric (800 yr BP) geological uplift event affecting a southern New Zealand coastline to test for the lasting genomic impacts of disturbance. Genome-wide analyses of three co-distributed keystone kelp taxa revealed that post-earthquake recolonization drove the evolution of novel, large-scale intertidal spatial genetic ‘sectors’ which are tightly linked to geological fault boundaries. Demographic simulations confirmed that, following widespread extirpation, parallel expansions into newly vacant habitats rapidly restructured genome-wide diversity. Interspecific differences in recolonization mode and tempo reflect differing ecological constraints relating to habitat choice and dispersal capacity among taxa. This study highlights the rapid and enduring evolutionary effects of catastrophic ecosystem disturbance and reveals the key role of range expansion in reshaping spatial genetic patterns.
... Fine sediment has been carried to the sea, and has smothered and suffocated tidal to intertidal shallow-marine ecosystems (Schiel et al., 2019). Coupled high sedimentation and coastal uplift has caused the biogeomorphology of the region to change dramatically following the earthquake (Schiel et al., 2019). ...
... Fine sediment has been carried to the sea, and has smothered and suffocated tidal to intertidal shallow-marine ecosystems (Schiel et al., 2019). Coupled high sedimentation and coastal uplift has caused the biogeomorphology of the region to change dramatically following the earthquake (Schiel et al., 2019). The ongoing stability of marine species has the potential to indicate sedimentation rates and the effect that the geomorphology of the area has on marine populations. ...
Preprint
Full-text available
Abstract. Mixed-method bicultural research in Aotearoa New Zealand, including the weaving of Indigenous and other knowledges, is experiencing a resurgence within many academic disciplines. However, mātauranga Māori – the knowledge, culture, value and worldview of the Indigenous peoples of Aotearoa New Zealand – and Te Ao Māori, the Māori world, is poorly represented within geomorphological investigations. Here, we review existing efforts to include Indigenous knowledge in geologic and geomorphic studies from the international research community and provide an overview of the current state of mātauranga Māori within research endeavours in Aotearoa New Zealand. We review three theoretical frameworks for including mātauranga Māori in research projects and three models for including Māori values within research. We identify direct benefits to geomorphology and discuss how these frameworks and models can be adapted for use with Indigenous knowledge systems outside of Aotearoa New Zealand. The aim of this review is to encourage geomorphologists around the world to engage with local Indigenous peoples to develop new approaches to geomorphic research. In Aotearoa New Zealand, we hope to inspire geomorphologists to embark on research journeys that engender genuine partnership with Māori and that promote toitū te mātauranga, the enduring protection, promotion and respect of mātauranga Māori.
... Southern bull kelps are classic primary foundation species because their large, heavy fronds control community structures through whiplash and shading, and their complex perennial holdfast provides biogenic habitats to highly diverse invertebrate communities [68,70,[75][76][77][78]. However, although the ecology of southern bull kelps as a primary foundation species has been studied in detail (see [79] and references therein), and diebacks following seismic uplifts, marine heatwaves and storms have been described [52,[80][81][82], it is unknown whether any alternative foundation species replace lost Durvillaea spp. ...
... The future of some New Zealand Durvillaea spp. populations is presently in doubt due to heatwave-induced die-backs and dramatic changes in shore height following seismic uplift in central New Zealand [52,80]. Durvillaea spp. ...
Article
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Southern bull kelps (Durvillaea spp., Fucales) are ‘primary’ foundation species that control community structures and ecosystem functions on temperate wave-exposed rocky reefs. However, these large foundation species are threatened by disturbances and stressors, including invasive species, sedimentation and heatwaves. It is unknown whether ‘alternative’ foundation species can replace lost southern bull kelps and its associated communities and networks. We compared community structure (by quantifying abundances of different species) and attachment-interaction networks (by quantifying which species were attached to other species) among plots dominated by Durvillaea spp. and plots where Durvillaea spp. were lost either through long-term repeated experimental removals or by recent stress from a marine heatwave. Long-term experimental removal plots were dominated by ‘alternative’ foundation species, the canopy-forming Cystophora spp. (Fucales), whereas the recent heatwave stressed plots were dominated by the invasive kelp Undaria pinnatifida (Laminariales). A network analysis of attachment interactions showed that communities differed among plots dominated by either Durvillaea spp., Cystophora spp. or U. pinnatifida, with different relationships between the primary, or alternative, foundation species and attached epiphytic ‘secondary’ foundation species. For example, native Cystophora spp. were more important as hosts for secondary foundation species compared to Durvillaea spp. and U. pinnatifida. Instead, Durvillaea spp. facilitated encrusting algae, which in turn provided habitat for gastropods. We conclude that (a) repeated disturbances and strong stressors can reveal ecological differences between primary and alternative foundation species, (b) analyses of abundances and attachment-networks are supplementary methods to identify linkages between primary, alternative and secondary foundation species, and (c) interspersed habitats dominated by different types of foundation species increase system-level biodiversity by supporting different species-abundance patterns and species-attachment networks.
... Similarly, the earthquakes causing rapid declines in species richness (H 0 ) of rocky intertidal community have also been reported in Kaikōura of November 2016, New Zealand (Schiel et al., 2019). The coseismic subsidence of 50-60 cm throughout the study area (Noda, Iwasaki, & Fukaya, 2016a) is considered a major cause of the decline of alpha diversity just after the earthquake because alpha diversity TA B L E 1 Time series of diversity index at shore scale and regional scale. ...
Article
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The impacts of large‐scale disturbance events on the species diversity of rocky intertidal sessile assemblages across multiple spatial scales are not well understood. To evaluate the influence of the 2011 Tohoku Earthquake on alpha and beta diversities of rocky intertidal sessile assemblages, we surveyed sessile assemblages in the mid‐shore zone from 2011 to 2019 and compared the data with those collected from 2003 to 2010 before the earthquake at the same region. The census was conducted across 22 study plots on five rocky shores along 30 km of the Sanriku Coast of Japan, which is located 150–160 km north–northwest of the earthquake epicenter. Alpha diversity was measured with three Hill numbers (H0, H1, and H2), which represent the number of equally common species that would exist in a community with the same diversity as the sampled community, with higher values of the subscript indicating more weight placed on abundant species. Beta diversity was measured with two metrics (BDtotal at two spatial scales). Values were compared between the post‐earthquake period (2011–2019) and the pre‐earthquake period (2003–2010). The results show that the Tohoku Earthquake significantly altered the species diversity of intertidal sessile assemblages across multiple spatial scales. All diversity metrics obtained at multiple spatial scales (i.e., alpha diversities: H0, H1, and H2; beta diversities: BDtotal at the shore and regional scales) decreased immediately after the earthquake and then increased in subsequent years. At 2 years after the earthquake, H0 recovered to within the range of pre‐earthquake values and H1 and H2 became significantly higher than pre‐earthquake values. Most metrics of alpha and beta diversities recovered to pre‐earthquake levels after several years, but regional BDtotal remained low for a longer period.
... Furthermore, fucoids, like other marine foundation species, build complex biogenic habitat, represented by many different morphological shapes and sizes of their holdfast, stipes, and fronds (e.g., with bladed or branches morphologies and sometimes air bladders and unique reproductive structures) (Fig. 2). Third, fucoids are, unfortunately, around the world and like other marine foundation species, threatened by stronger heatwaves, sediment-smothering, overgrazing, biological invasions, coastal darkening and eutrophication (Kautsky et al. 1986, Smale and Wernberg 2013, Valdazo et al. 2017, Schiel et al. 2019, Valdazo et al. 2020, Thomsen et al. 2021, Verdura et al. 2021, Fragkopoulou et al. 2022, Pessarrodona 2022, Wernberg et al. 2024. Fucoids should therefore be included in conservation and restoration to the same extent as other marine foundation species (Bellgrove et al. 2010, Bellgrove et al. 2017, Vergés et al. 2020, Eger et al. 2022b, Whitaker et al. 2023. ...
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1. Fucoid forests are areas dominated by marine brown seaweed in the taxonomic order Fucales that, like the better-known marine foundation species - corals, kelps, seagrasses, salt marshes, and mangroves - are threatened by anthropogenic stressors. 2. Fucoid forests are fabulous and important because they, like the better-known marine foundation species (i) span large areas, bioregions, and ecosystems, (ii) provide ecological functions such as high productivity and biodiversity, and (iii) support a variety of ecosystem services including habitat for commercial fishery species, food for humans and cultural values. 3. Fucoid forests are, based on a new citation analysis, forgotten worldwide, because they are described orders of magnitude less than the better-known marine foundation species, in ecology and marine biology textbooks, in Google Scholar and Scopus databases over scientific literature, and in recent reports and reviews about seaweed forests. 4. Fucoid forests would be less forgotten if more people acknowledge their biological importance and societal value more often and equate their importance to that of the better-known marine foundation species. Perhaps name-recognition would also improve if fucoids are unified under a non-taxonomic common name across teaching, research, management, and conservation, like the better-known marine foundation species. We agree with the marine scientists that have used ‘rockweed’ as such a common name to describe all fucoids, but other seaweed-experts disagree because they (a) do not agree fucoids are forgotten, (b) dislike common names or (c) argue rockweed should only describe fucoid species in the family Fucaceae.
... This earthquake was exceptionally complex in geological terms, involving ruptures along at least 12 separate major fault systems, and the extent of vertical uplift was highly variable across this coastal zone, ranging from < 0.5 m to at least 6 m (Clark et al. 2017, Kaiser et al. 2017, Xu et al. 2018, Reid et al. 2020). This tectonic event eliminated intertidal biota along substantial stretches of the affected shoreline (Schiel et al. 2019, 2021, Thomsen et al. 2020. Ongoing surveillance of intertidal macroalgae has confirmed extensive extirpation in many uplifted areas , 2021, Reid et al. 2020, Thomsen et al. 2020, 2021), but has also identified the local survival of some species (albeit often at reduced densities) in locations with relatively low uplift (< 2 m; Thomsen et al. 2020, 2021. ...
Article
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Large‐scale disturbance events provide ideal opportunities to directly study recolonisation processes in natural environments, via the removal of competitors and the formation of newly vacant habitat. A high magnitude earthquake in central New Zealand in 2016 created major ecological disturbance, with coastal tectonic uplift of up to ~ 6 m extirpating vast swathes of intertidal organisms. One of the affected species was Durvillaea antarctica (rimurapa or southern bull kelp), which is an important habitat‐forming intertidal macroalga capable of long‐distance dispersal. Across the complex fault system with varying amounts of uplift, the species was either locally extirpated or heavily reduced in abundance. We hypothesised that neutral priority effects and chance dispersal from other populations would influence which lineages would establish. We sampled individuals of D. antarctica across the uplift zone immediately after the earthquake in 2016 and then repeatedly sampled new recruits in the same areas between 2017 and 2020, using genotyping‐by‐sequencing to provide ‘before' and ‘after' genomic comparisons. Our results revealed strong geographic clustering but little evidence of new lineages establishing at disturbed sites, although populations at uplifted sites remain at remarkably low densities. We infer that recolonisation has thus far primarily originated from refugial, remnant patches within the uplift zone. To complement the phylogeographic analysis, we estimated oceanographic connectivity among the uplift zone sample locations. The connectivity modelling estimated that northbound dispersal of D. antarctica was more likely, but we have not yet detected southern genotypes in the recolonised populations. As the ongoing recolonisation process transitions from an ecological to an evolutionary timescale, change remains possible. This study provides the first genomic ‘snapshots' of a natural recolonisation process following a large‐scale ecological disturbance event, and ongoing research has the potential to reveal important insight into both micro‐ and macroevolutionary processes.
... Here, we use the opportunity presented by the 7.8 magnitude 2016 'Kaik oura earthquake' in Aotearoa New Zealand to examine the influence of a major ecological disturbance on the microbiome composition of southern bull kelp, Durvillaea antarctica. This earthquake led to a non-uniform coastal uplift of up to $6 m across $160 km of the coast (Clark et al., 2017;Schiel et al., 2019), leading to localized extirpation of some southern bull kelp populations (Peters et al., 2020). The patchiness of the uplift resulted in some affected ecosystems being geographically close to relatively unaffected populations, and we leveraged this proximity to compare the influence of tissue type, host age and disturbance level on the microbiome of D. antarctica. ...
Article
Host‐associated microbial communities are shaped by myriad factors ranging from host conditions, environmental conditions and other microbes. Disentangling the ecological impact of each of these factors can be particularly difficult as many variables are correlated. Here, we leveraged earthquake‐induced changes in host population structure to assess the influence of population crashes on marine microbial ecosystems. A large (7.8 magnitude) earthquake in New Zealand in 2016 led to widespread coastal uplift of up to ~6 m, sufficient to locally extirpate some intertidal southern bull kelp populations. These uplifted populations are slowly recovering, but remain at much lower densities than at nearby, less‐uplifted sites. By comparing the microbial communities of the hosts from disturbed and relatively undisturbed populations using 16S rRNA gene amplicon sequencing, we observed that disturbed host populations supported higher functional, taxonomic and phylogenetic microbial beta diversity than non‐disturbed host populations. Our findings shed light on microbiome ecological assembly processes, particularly highlighting that large‐scale disturbances that affect host populations can dramatically influence microbiome structure. We suggest that disturbance‐induced changes in host density limit the dispersal opportunities of microbes, with host community connectivity declining with the density of host populations.
... Following the disturbance, there was a large-scale intertidal bloom of ephemeral algae, such as Ulva, northward of Kaikōura . The bloom seems likely to have resulted from a massive die-off of molluscan grazers in the region due to the uplift (Schiel et al., 2019). However, our observations at Raramai suggested that the uplift was much smaller, <0.5 m, which likely was still enough to influence green algae colonization. ...
Article
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Top‐down and bottom‐up factors and their interaction highlight the interdependence of resources and consumer impacts on food webs and ecosystems. Variation in the strength of upwelling‐mediated ecological controls (i.e., light availability and herbivory) between early and late succession stages is less well understood from the standpoint of influencing algal functional group composition. We experimentally tested the effect of light, grazing, and disturbance on rocky intertidal turf‐forming algal communities. Studies were conducted on the South Island of New Zealand at Raramai on the east coast (a persistent downwelling region) and Twelve Mile Beach on the west coast (an intermittent upwelling region). Herbivory, light availability, and algal cover were manipulated and percent cover of major macroalgal functional groups and sessile invertebrates were measured monthly from October 2017 to March 2018. By distinguishing between algal functional groups and including different starting conditions in our design, we found that the mosaic‐like pattern of bare rock intermingled with diverse turf‐forming algae at Twelve Mile Beach was driven by a complex array of species interactions, including grazing, predation, preemptive competition and interference competition, colonization rates, and these interactions were modulated by light availability and other environmental conditions. Raramai results contrasted with those at Twelve Mile Beach in showing stronger effects of grazing and relatively weak effects of other interactions, low colonization rates of invertebrates, and light effects limited to crustose algae. Our study highlights the potential importance of an upwelling‐mediated 3‐way interaction among herbivory, light availability, and preemption in structuring contrasting low rocky intertidal macroalgal communities.
... Uniquely, the pāua fishery was closed for a 5-year period to facilitate recovery from the 2016 7.8 M w Kaikōura earthquake. This event devastated the nearshore environment due to a combination of co-seismic sea-level changes and longer term erosion and sedimentation effects that had severe ecological impacts on habitat-forming seaweeds and other marine life [45,53,56,59]. ...
... Some of these can be overcome, however, by taking advantage of large-scale disturbance events that cause widespread changes to reef communities. For example, previous studies using both historical and contemporary tectonic events have shown significant changes to key rocky reef biota as a consequence of coastal uplift and subsidence in Chile, Japan, and New Zealand (e.g., Castilla et al., 2010;Orchard et al., 2021;Sakanishi et al., 2018;Schiel et al., 2019;Suzuki et al., 2017;Vaux et al., 2021). However, the majority of studies investigating the consequences of tectonic shifts have predominately focused on the abundances of key species lost and gained over time, with few studies directly considering the functional aspects related to these changes (but see Reed et al., 2011). ...
Article
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Habitat-forming macroalgae are widely recognized as one of the most productive ecosystems on earth. However, relatively little is known about the variation in productivity over large spatiotemporal scales and the relative importance of environmental and biotic factors in influencing the quantity of carbon fixed. Here we leverage a large tectonic event to understand how fluctuations in the biomass of habitat-forming macroalgae and changes in light availability influence primary productivity along 130 km of coastline over 5 years. We also quantify the effects of changes to species composition on primary productivity. This study revealed significant implications of a compromised light environment for the biomass of macroalgae and productivity rates. Immediately post-earthquake, there was a substantial loss of biomass (an average of −83%) of a previously dominant large brown alga, Durvillaea spp., and very limited recovery of biomass over the next 5 years. Reductions in biomass coupled with changes in light attenuation resulted in average net primary production (NPP) from Durvillaea decreasing from 1130 g C m −2 year −1 before the earthquake to 192 g C m −2 year −1 after 5 years. Partial compensation of reduced NPP was facilitated by increases in the biomass of a smaller fucoid Carpophyllum maschalocarpum, but its productivity was considerably less on average, resulting in a reduction in carbon fixation. Overall, reductions in biomass resulted in a 2-fold to 10-fold drop in carbon fixation by canopy-forming macroalgae over at least 5 years, while a degradation of the light environment further compromised primary productivity, and most likely detrital subsidies of organic matter to the nearshore ecosystem.
... It seems likely, therefore, that as ocean and air temperatures increase and die-offs become more common, the upper vertical limit of each of these species will probably shift towards the low intertidal zone (Harley, 2011). Indeed, there was a large and well-documented die-off followed by a vertical shift downwards after a large earthquake in 2016 (Schiel et al., 2021;Schiel et al., 2019). Furthermore, stressed C. denticulata also consumed less oxygen in their first hour after immersion than their non-stressed congeners. ...
Article
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Limpets help maintain bare space and act as sentinel species of thermal stress in intertidal reef ecosystems. However , little is known about the physiological responses of New Zealand's widely distributed Cellana spp. limpets to thermal stress. We tested if there were differences in thermal tolerance in summer and winter and heat shock protein concentrations among four Cellana species that occupy different shore elevations. For one highly abundant species (C. denticulata), we tested whether thermal tolerance was affected by limpet size in summer and winter and whether thermal tolerance and oxygen consumption in air and water were affected by repeated heat stress. Limpet species from higher shore elevations did not always have higher breakpoint temperatures than those from lower elevations, potentially due to differences in homing behaviour. Similarly, there was no effect of size, season , or repeated heat stress on thermal tolerance. HSP70 concentrations were highest in C. denticulata, but were not affected by temperature (19-34°C), indicating that limpets maintain high concentrations of constitutive HSP70. Limpets exposed to repeated heat stress in air had higher heart rates and oxygen consumption than those maintained at ambient temperature (19°C). However, when both treatments were flooded with 18°C seawater, heart rates were similar, but oxygen consumption was greater in the ambient treatment, indicating that non-stressed limpets may incur an oxygen debt during aerial exposure. This study provides new understanding about the effect of acute and repeated heat stress on the physiology of these conspicuous and abundant grazing invertebrates , which will help better predict their distributions in response to climate change.
... The November 2016 Kaikōura earthquakes and coastal uplift caused extensive damage to pāua (Haliotis iris) populations and critical habitats along 130 km of coastline, with widespread mortality of juvenile and adult pāua in a very productive fishery. The resulting emergency ban on all commercial and recreational pāua harvest lasted over 5 years, during which researchers from University of Canterbury documented a remarkable rebuilding of inshore populations (Schiel et al. 2019. Repeated surveys over 5 years showed rejuvenation of inshore habitats for recruiting pāua, a steady build-up of juvenile populations, and a significant increase in large, legal-sized pāua (≥ 125 mm shell length, SL) in very shallow habitats. ...
Technical Report
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Effects of shore-based recreational fishing on paua populations following a 5-year fishery closure
... Earthquakes can displace non-dispersive benthic communities and, depending on the magnitude of land-level change and shore type, lead to regional extirpation of intertidal and shallow subtidal biota (Chunga-Llauce & Pacheco, 2021; Figure 1a). On rocky shores, for instance, observations from the 2016 Kaikōura earthquake in southern New Zealand showed extensive coastal uplift can cause local extirpation of rocky reef communities (Peters et al., 2020;Schiel et al., 2019), providing new empty intertidal habitats for the recolonization of dispersing genetic lineages in the disturbed zone (Peters et al., 2020). The co-seismic subsidence of rocky intertidal zone following the 2011 Great East Japan earthquake immediately shifted some sessile coastal invertebrates downward and decreased the abundance of several sessile and mobile species (Noda et al., 2016). ...
Article
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Aim: Coastal habitats are among the most dynamic environments on earth and are highly vulnerable to large‐scale physical disturbance. Genetic studies of nearshore marine species are revealing long‐lasting signatures of major coastal disturbance events. We synthesize emerging data to highlight how physical perturbations can impact the phylogeographic patterns of coastal populations. Taxon: Coastal marine and estuarine taxa. Location: Coastal regions around the globe. Methods: We synthesize coastal genetic and genomic literature, focussing particularly on the phylogeographic consequences of natural disturbance events including uplift, tsunami, hurricanes, glaciations and sea‐level fluctuations. We focus on studies with clear physical analytical frameworks constrained by abiotic data. Results: Tectonic and atmospheric disruptions can be considered short‐term events with major impacts on populations adjacent to the centre of disturbance, typically resulting in the evolution of shallow phylogeographic patterns. Long‐lived climate‐driven disturbances such as glaciations, however, operate over vast geographic scales and often drive deep evolutionary patterns in affected populations. We show that studies using genome‐wide data could better identify fine‐scale signatures of both past and contemporary habitat perturbations. Conclusions: Recent data reveal the interplay between physical upheaval and coastal phylogeography, indicating that disturbance can affect diversity, connectivity and demography of coastal populations. The interplay between long‐lived large‐scale disturbance and species‐specific biotic traits has shaped deep phylogeographic patterns of coastal taxa. Additionally, it could be argued that, at least for some regions, short‐term disturbance is the ‘rule’ rather than the ‘exception’, and thus, represents a key driver of coastal genetic patterns in disturbance prone coastal regions. Geo‐genomic approaches that combine genome‐wide data with explicit habitat models or disturbance history information have been particularly successful in explaining the drivers of coastal evolutionary change. We argue that future integration of genomic and physical data will be crucial for tracing evolutionary trends in fast‐changing marine environments.
... Earthquake uplift can therefore cause mortality in D. antarctica if it is sufficient to move individuals above the high tide mark. For example, shores uplifted by several metres during the 2010 Chilean and 2016 Kaikōura earthquakes resulted in large-scale die-offs of intertidal Durvillaea (Castilla et al., 2010;Clark et al., 2017;Peters et al., 2020;Schiel et al., 2019;Tait et al., 2021;Thomsen et al., 2021 (Fraser, Davies, et al., 2018). ...
Article
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Large‐scale disturbance events have the potential to drastically reshape biodiversity patterns. Notably, newly vacant habitat space cleared by disturbance can be colonised by multiple lineages, which can lead to the evolution of distinct spatial ‘sectors’ of genetic diversity within a species. We test for disturbance‐driven sectoring of genetic diversity in intertidal southern bull kelp, Durvillaea antarctica (Chamisso) Hariot following the high‐magnitude 1855 Wairarapa earthquake in New Zealand. Specifically, we use genotyping‐by‐sequencing (GBS) to analyse fine‐scale population structure across the uplift zone and apply machine learning to assess the fit of alternative recolonisaton models. Our analysis reveals that specimens from the uplift zone carry distinctive genomic signatures potentially linked to post‐earthquake recolonisation processes. Specifically, our analysis identifies two parapatric spatial‐genomic sectors of D. antarctica at Turakirae Head, which experienced the most dramatic uplift. Based on phylogeographic modelling, we infer that bull kelp in the Wellington region was likely a source for recolonisation of the heavily uplifted Turakirae Head coastline, via two parallel, eastward recolonisation events. By identifying multiple parapatric genotypic sectors within a recently recolonised coastal region, the current study provides support for the hypothesis that competing lineage expansions can generate striking spatial structuring of genetic diversity, even in highly dispersive taxa.
... All studies reviewed found a strong negative relationship between benthic sediment accumulation and kelp survival with near total extirpation of floating and nonfloating kelp species after the introduction of large volumes of sediment from mine tailings ; landslides (Schiel et al., 2019); discharged sewage effluent (Stull, 1996); and in the Salish Sea, dam removal (Rubin et al., 2017) ( Figure 5). ...
Article
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Kelp forests are in decline across much of their range due to place-specific combinations of local and global stressors. Declines in kelp abundance can lead to cascading losses of biodiversity and productivity with far-reaching ecological and socioeconomic consequences. The Salish Sea is a hotspot of kelp diversity where many species of kelp provide critical habitat and food for commercially, ecologically, and culturally important fish and invertebrate species. However, like other regions, kelp forests in much of the Salish Sea are in rapid decline. Data gaps and limited long-term monitoring have hampered attempts to identify and manage for specific drivers of decline, despite the documented urgency to protect these important habitats. To address these knowledge gaps, we gathered a focus group of experts on kelp in the Salish Sea to identify perceived direct and indirect stressors facing kelp forests. We then conducted a comprehensive literature review of peer-reviewed studies from the Salish Sea and temperate coastal ecosystems worldwide to assess the level of support for the pathways identified by the experts, and we identified knowledge gaps to prioritize future research. Our results revealed major research gaps within the Salish Sea and highlighted the potential to use expert knowledge for making informed decisions in the region. We found high support for the pathways in the global literature, with variable consensus on the relationship between stressors and responses across studies, confirming the influence of local ecological, oceanographic, and anthropogenic contexts and threshold effects on stressor–response relationships. Finally, we prioritized areas for future research in the Salish Sea. This study demonstrates the value expert opinion has to inform management decisions. These methods are readily adaptable to other ecosystem management contexts, and the results of this case study can be immediately applied to kelp management.
... Of particular importance economically was the great mortality of NZ black-foot abalone, Haliotis iris (Gerrity et al., 2020). Tens of thousands of individuals were propelled upwards beyond the tidal influence where they suffered severe heat stress and died (picture in Schiel et al., 2019). Their recruitment habitats among small rocks in the lowest intertidal and upper subtidal zone were also uplifted along much of the coast, causing concerns about future recruitment rates. ...
Article
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Understanding the resilience and recovery processes of coastal marine ecosystems is of increasing importance in the face of increasing disturbances and stressors. Large-scale, catastrophic events can re-set the structure and functioning of ecosystems, and potentially lead to different stable states. Such an event occurred in south-eastern New Zealand when a Mw 7.8 earthquake lifted the coastline by up to 6 m. This caused widespread mortality of intertidal algal and invertebrate communities over 130 km of coast. This study involved structured and detailed sampling of three intertidal zones at 16 sites nested into four degree of uplift (none, 0.4–1, 1.5–2.5, and 4.5–6 m). Recovery of large brown algal assemblages, the canopy species of which were almost entirely fucoids, were devastated by the uplift, and recovery after 4 years was generally poor except at sites with < 1 m of uplift. The physical infrastructural changes to reefs were severe, with intertidal emersion temperatures frequently above 35°C and up to 50°C, which was lethal to remnant populations and recruiting algae. Erosion of the reefs composed of soft sedimentary rocks was severe. Shifting sand and gravel covered some lower reef areas during storms, and the nearshore light environment was frequently below compensation points for algal production, especially for the largest fucoid Durvillaea antarctica/poha. Low uplift sites recovered much of their pre-earthquake assemblages, but only in the low tidal zone. The mid and high tidal zones of all uplifted sites remained depauperate. Fucoids recruited well in the low zone of low uplift sites but then were affected by a severe heat wave a year after the earthquake that reduced their cover. This was followed by a great increase in fleshy red algae, which then precluded recruitment of large brown algae. The interactions of species’ life histories and the altered physical and ecological infrastructure on which they rely are instructive for attempts to lessen manageable stressors in coastal environments and help future-proof against the effects of compounded impacts.
... The project has documented a wide range of biological and physical impacts in the coastal environment over the past four years. These include the widespread mortality of habitat-forming species that support characteristic ecosystems and natural resources on the coast (Alestra et al. 2021;Schiel et al. 2019;Tait et al. 2021). Due to the popularity of the coast for recreational use, interactions between people and the recovering environment are an important influence on recovery processes. ...
Technical Report
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This report contributes to a collaborative project between the Marlborough District Council (MDC) and University of Canterbury (UC) which aims to help protect and promote the recovery of native dune systems on the Marlborough coast. It is centred around the mapping of dune vegetation and identification of dune protection zones for old-growth seed sources of the native sand-binders spinifex (Spinifex sericeus) and pīngao (Ficinia spiralis). Both are key habitat-formers associated with nationally threatened dune ecosystems, and pīngao is an important weaving resource and Ngāi Tahu taonga species. The primary goal is to protect existing seed sources that are vital for natural regeneration following major disturbances such as the earthquake event. Several additional protection zones are also identified for areas where new dunes are successfully regenerating, including areas being actively restored in the Beach Aid project that is assisting new native dunes to become established where there is available space.
... Pacific Conservation Biology C study period, but they have been recorded in the past. All of the study sites, with the exception of Oaro, were affected by tectonic uplift of between 0.6 and 0.9 m during the 2016 Kaikōura earthquake (Clark et al. 2017;Schiel et al. 2019), which has generally increased the elevation of these lagoons and lower river reaches in relation to sea level. In the case of Lyell Creek and Middle Creek high spring tides would occasionally inundate the lower reaches pre-earthquake, but this no longer occurs since the uplift event (P. ...
Article
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Galaxias maculatus is a declining amphidromous fish that supports New Zealand’s culturally-important whitebait fisheries targeting the migratory juvenile stage. Spawning ground protection and rehabilitation is required to reverse historical degradation and improve fisheries prospects alongside conservation goals. Although spawning habitat has been characterised in tidal rivers, there has been no previous study of spawning in non-tidal rivermouths that are open to the sea. We assessed seven non-tidal rivers over four months using census surveys to quantify spawning activity, identify environmental cues, and characterise fundamental aspects of the biogeography of spawning grounds. Results include the identification of compact spawning reaches near the rivermouths. Spawning events were triggered by periods of elevated water levels that were often of very short duration suggesting that potential lunar cues were less important, and that rapid fish movements had likely occurred within the catchment prior to spawning events. Spawning grounds exhibited consistent vertical structuring above typical low-flow levels, with associated horizontal translation away from the river channel leading to increased exposure to anthropogenic stressors and associated management implications for protecting the areas concerned. These consistent patterns provide a sound basis for advancing protective management at non-tidal rivermouths. Attention to flood management, vegetation control, and bankside recreational activities is needed and may be assisted by elucidating the biogeography of spawning grounds. The identification of rapid responses to environmental cues deserves further research to assess floodplain connectivity aspects that enable fish movements in emphemeral flowpaths, and as a confounding factor in commonly-used fish survey techniques.
... This concern is particularly pertinent to New Zealand as it lies on the Ring of Fire and the Indo-Pacific plate subduction zone, and is therefore prone to volcanic and tectonic disruption. As shown by Schiel et al. (2019) (Whittaker & Fernandez-Palacios, 2007), although little work appears to have been conducted on freshwater-marine ecosystem linkages under a changing climate. ...
Article
Island nations such as New Zealand provide valuable insights into conservation challenges posed by strongly connected and recently developed or exploited freshwater and marine ecosystems. The narrow land mass, high rainfall, and steep terrain of New Zealand, like many other island nations, mean that land‐based stressors are rapidly transferred to freshwater habitats and propagated downstream to coastal environments via short, fast‐flowing river systems. Freshwater and marine environments are linked through faunal life histories; for example, diadromous fishes, many of which are considered threatened or at risk of extinction, and require cross‐ecosystem conservation to ensure survival of critical life stages and persistence of source populations. Recent invasions of marine and freshwater environments by non‐indigenous species reveal rapid impacts on a naïve biota and highlight conservation conundrums caused by management aimed at enhancing native biodiversity by improving habitat connectivity. Understanding and managing interconnected freshwater and marine ecosystems is a key concept for local indigenous communities, and highlights socio‐cultural connectivity and sustainable local harvesting of traditional resources as key elements of contemporary marine and freshwater conservation planning in New Zealand.
Thesis
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Marine macroalgal communities (often termed ‘forests’) are ubiquitous worldwide and underpin economical, ecological, and cultural services. In temperate coastal seas, macroalgae can be ten times more productive than phytoplankton, potentially playing a very large role in carbon cycle and fixation in coastal ecosystems. Light reaching the seabed fuels macroalgal productivity and ultimately provides the basis of the inward flow of energy and matter further up the trophic web that macroalgae form the basis. However, the benthic light environment around shorelines is deteriorating in many places through a combination of intensification of land use, urbanisation, and the flow of contaminants from the land to the sea, which ultimately affect macroalgal communities. Moreover, the delivery of light on the seabed is intrinsically dynamic, substantially varying on small to large spatial and temporal scales so the quantification of the underwater light environment is challenging. Recently, novel satellite-based methods have been developed to measure seabed light, and in Chapter Two I developed and analysed 20 years of seabed light data based on satellite remote sensing of ocean colour at New Zealand scale. I showed the utility and application of such satellite data and determined for the first time the amount of rocky reef area receiving enough light to sustain macroalgal communities around New Zealand. Moreover, I found evidence of a changing light environment and identified drivers that varied across seasons and regions. Satellite-derived seabed light estimates show great promise in advancing our understanding of the underwater light environment, especially at spatial scales greater than about 1 km and temporal scales from days to decades. The delivery of light on the seabed is also variable at finer temporal and spectral scales. In Chapter Three I developed an optical model of instant light delivery to macroalgae and showed that changes in spectral light quality on the seabed can produce shifts in macroalgal community composition. Moreover, the type of optically active constituents (phytoplankton, non-algal particles or colour dissolved organic matter) dominating light attenuation in the water column can promote specific algal taxa on the benthos. Optical modelling and satellite remote sensing of seabed light quantity and quality presented a promising synergy to understand the consequences of a changing light environment on macroalgal communities at different scales. Alongside light availability, sea temperature is arguably one of the most fundamental drivers of macroalgal distribution. Marine heatwaves (MHWs) pose a direct threat to temperate rocky reefs ecosystems and the ecosystem services they deliver, however most biological impacts from MHWs have been documented during summer, whereas MHWs can occur at all seasons. In Chapter Four and Appendix I, I showed that 40-year trends in coastal MHW metrics were variable across seasons, and between metrics globally and around New Zealand. This suggests that species-specific life histories occurring outside the summer window are likely to be affected. Moreover, the breakpoint analyses showed an intensification of MHW regimes that varied amongst regions and seasons. Such analyses should provide guidance to environmental managers and help identify regions where ecological monitoring is lacking in the face of changing thermal conditions and the race against time (and temperature) to establish baselines. I showed in Appendix II that the dynamics of a habitat-forming macroalgae was negatively affected during MHWs and periods of lower water clarity, but more work should focus on understanding the complex linkage between light availability and MHWs, given their convoluted nature. Overall, this thesis contributed by improving our knowledge of seabed light delivery in terms of quantity and quality as well as the seasonal dynamics of coastal MHWs at global scale and around New Zealand. This thesis sets important milestones towards better understanding seabed irradiance, its drivers and the linkage with macroalgal distribution and productivity. Importantly, the methods developed in this work have closed the gaps between remote sensing, optical modelling and algal physiology to enable better understanding of the effects of land-use and climate change to improve coastal stewardship.
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Historical vicariance events, linked to the existence of stable physical barriers to gene flow, generate concordant genetic breaks in co-distributed species while stochastic processes (e.g., costal uplift) could cause species-specific genetic breaks as a result of local strong demographic bottlenecks or extinction. In Chile, previous studies show that the area of the 30°S-33°S could correspond to a stable barrier to gene flow that have affected the genetic structure of various algae and marine invertebrates. Here we sequenced two organellar genes (COI and rbcL) in four taxonomically accepted co-distributed red seaweeds species characterized by a low dispersal potential: Mazzaella laminarioides, M. membranacea, Asterfilopsis disciplinalis, and Ahnfeltiopsis vermicularis. Our results revealed the existence of ten strongly differentiated linages in the taxa studied. Strong genetic breaks, concordant in both space and time (divergence estimated to have occurred some 2.9–12.4 million years ago), were observed between taxa distributed across the 33°S. Conversely, in the Central/South part of the Chilean coast, the localization of the genetic breaks/sub-structure observed varied widely (36°S, 38°S, 39°S, and 40°S). These results suggest that a major historical vicariance event has modeled the genetic structure of several Chilean marine organisms in the north of the Chilean coast during the mid-Miocene, while more recent stochastic events and genetic drift could be the driving forces of genetic divergence/structuration in the central-southern part of the coast.
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The impacts of natural disasters on marine mammals are poorly understood and difficult to study, which can hamper management responses following such events. This study provides the first distribution and abundance assessment of New Zealand fur seal (NZFS: Arctocephalus forsteri ) colonies around Kaikōura, New Zealand, since a 7.8 magnitude earthquake in November 2016 caused substantial changes to both the local marine and terrestrial environments, and led to the reconstruction of a major highway that runs adjacent to NZFS colonies. Mark–recapture and direct counts in the 2022–2023 breeding season estimated pup production for NZFS breeding colonies along the Kaikōura coast. Using established multipliers, pup estimates were used to provide the first comprehensive population estimate for Kaikōura's NZFS population since the earthquake. Three new colonies and three new subcolonies were assessed and recorded, additional to reassessments of two established colonies. Overall, Kaikōura's NZFS population has grown and spread post‐earthquake, with an upper total population estimate of between 21,560 and 28,327 animals in the 2022–2023 breeding season. Some sites, such as Lynch's Reef, appear to have benefited from earthquake‐induced coastal uplift, with pup production increasing. Contrastingly, the estimated 2,401 (±99) pups produced at Ōhau Point in 2023 is similar to pre‐earthquake estimates. This indicates that the earthquake has disrupted previously documented growth at this site. The distribution of NZFS breeding at Ōhau Point has also changed substantially since the last pre‐earthquake assessment. From these findings, alterations to the Ōhau Point New Zealand Fur Seal Sanctuary and similar protections at other locations on the Kaikōura coast are suggested, as greater numbers of NZFSs are now accessible to human interaction and disturbance. The results demonstrate both how natural disasters and subsequent infrastructure modifications can impact coastal species and how conservation measures may need to be amended accordingly.
Article
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Marine heatwaves (MHWs) have increased worldwide in intensity, frequency, and duration, often with severe impacts on ecologically and socioeconomically important coastal habitats. Most MHW studies have focused on summer events in specific regions or global open-water analyses with little consideration to seasonality or spatial biogeography of the nearshore zone. We address this research gap by analysing changes to MHWs across seasons and ecoregions, within 12 nautical miles (NM) of New Zealand's coastline, an area with high biodiversity and endemism. We used season-specific linear trend analysis with temporal breakpoints between 1982 and 2021 to identify the number of MHW events and MHW days, and mean, maximum, and cumulative intensity of MHWs for New Zealand coastal ecoregions. Across ecoregions, 69.5% of 200 trend analyses increased significantly whereas the remaining 30.5% were unaffected. For the significant increases, temporal breakpoints occurred between 1994 and 2012. We conclude that MHWs have become stronger, longer and more frequent across coastal New Zealand, but with some variability within and between regions. Our trend-analyses could enable retrospective analyses of biological tipping-points and inform management practices that may enhance the resilience of ecoregions yet to face MHW breakpoints or those in the initial stages of major climatic changes.
Preprint
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Pāua (abalone) are a treasured natural resource that supports a recreational fishery worth $2 million annually to the local economy of the Kaikōura district in New Zealand. From 2016, the fishery was closed for 5 years in response to widespread mortality caused by co-seismic uplift in the 7.8 Mw Kaikōura earthquake. The fishery re-opened in 2021 for an initial 3-month open season with a recreational fishing allocation of 5 tonnes. We constructed scenario models informed by fishing pressure observations and show that this catch target was severely exceeded (by a factor of 9-10). We then evaluated a range of alternative management settings involving daily bag limit adjustments and temporal controls that shift opening times away from high visitation periods and favourable weather conditions as a means to reduce peaks in fishing pressure. Temporal control strategies reduced seasonal catch by up to 45% in comparative analyses using the 2021 fishing effort as a base-case scenario, and can be used in combination with daily bag limit adjustments and longer-term protected areas. When applied to a Total Allowable Catch, these solutions also produce equity effects that increase the proportional allocation accruing to local fishers. We discuss the potential role of these insights in designing temporal controls for managing seasonal influxes of fishing effort driven by tourism, and highlight the role of natural disasters and recovery periods as a trigger for new policy directions. In this case, they were needed to address an unexpected loss that illustrates a more general need for reliable fishery management that is responsive to environmental change in the long term.
Article
Rocky reefs throughout the temperate zone are dominated by large brown algae, which are major foundation species and ecosystem engineers. There is usually an ecological bottleneck at the early life stage of such algae when they are vulnerable to a wide range of stressors. A large earthquake that affected the coastline of southern New Zealand highlighted the combined effects of sudden changes to multiple stressors on large algal assemblages. In particular, the regime of temperature, sediment and light suddenly changed as the coastal platform was lifted, and sediments from the catchment occluded the light environment of nearshore waters. Here we tested the effects of these stressors on early survival and growth of 3 formerly dominant species—the fucoids Landsburgia quercifolia and Durvillaea antarctica and the laminarian Lessonia variegat a —over 100 d using a culture laboratory. After 42 d, interactive effects were found for growth of all species. Decreasing light and increasing temperature had the greatest negative effect on L. variegata and D. antarctica growth. Growth was minimal at the lowest light treatment (PAR: 16 µmol m ⁻² s ⁻¹ ) for all species, but often least growth was found at the highest sediment treatment (PAR: 32 µmol m ⁻² s ⁻¹ ). L. quercifolia was resilient to increasing temperature, whereas survival and growth decreased with increasing temperature for D. antarctica and L. variegata. These results are highly suggestive of the coincident influences of major stressors on the post-earthquake marine ecosystem. These results also highlight that recovery of large brown algae following disturbance events is likely to be slow due to an increase in coastal sedimentation and extreme water temperature.
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Abstract Aotearoa New Zealand is the last major landmass settled by people, and therefore provides a recent record of ecological legacy effects in the coastal zone. Large‐scale land clearances of forests accelerated over the last century, affecting the concentration of suspended sediments, light environment, and nutrient composition on rocky reefs, and consequently the distribution, abundance, and composition of algal forests. The environmental effects were compounded in many places by overfishing and long‐term declines of large predatory species, often leading to proliferation and extensive grazing by sea urchins. In this study, we examine these processes in three biogeographic regions that have been differentially affected by ecological legacy effects. The study was based on the depth‐specific associations between sea urchins (Evechinus chloroticus) and the common kelp (Ecklonia radiata) from multiple sites within each region, some of which were sampled over two decades within no‐take marine reserves and in actively fished areas. Satellite‐derived estimates of water‐column properties were used as proxies for the relative effects of coastal sedimentation on kelp forest habitats. We then used an information‐theoretic framework to assess the relative factor weightings of marine reserve effects on urchin density, total suspended solids (TSS), and regional urchin density on the depth‐specific density of Ecklonia radiata. The fishing effects were significant within and outside of reserves in the northern and central regions, but the effect sizes were by far strongest in the northern region. In the central region characterized by extensive land clearance and forestry combined with high coastal retention of water, the concentration of TSS had a major influence on the depth distribution of kelp, confining it to shallow water (
Article
After New Zealand's 7.8 Mw Kaikōura earthquake in late 2016 an unexpected anthropogenic effect involved increased motorised vehicle access to beaches. We show how these effects were generated by landscape reconfiguration associated with coastal uplift and widening of high-tide beaches, and present analyses of the distribution of natural environment values in relation to vehicle movements and impacts. Access changes led to extensive vehicle tracking in remote areas that had previously been protected by natural barriers. New dunes formed seaward of old dunes and have statutory protection as threatened ecosystems, yet are affected by vehicle traffic. Nesting grounds of nationally vulnerable banded dotterel (Charadrius bicinctus bicinctus) co-occur with vehicle tracking. An artificial nest experiment showed that vehicle strikes pose risks to nesting success, with 91% and 83% of nests destroyed in high and moderate-traffic areas, respectively, despite an increase in suitable habitat. Despite gains for recreational vehicle users there are serious trade-offs with environmental values subject to legal protection and associated responsibilities for management authorities. In theory, a combination of low-impact vehicle access and environmental protection could generate win-win outcomes from the landscape changes, but is difficult to achieve in practice. Detailed information on sensitive areas would be required to inform designated vehicle routes as a potential solution, and such sensitivities are widespread. Alternatively, vehicle access areas that accommodate longstanding activities such as boat launching could be formally established using identified boundaries to control impacts further afield. Difficulties for the enforcement of regulatory measures in remote areas also suggest a need for motivational strategies that incentivise low-impact behaviours. We discuss options for user groups to voluntarily reduce their impacts, the importance of interactions at the recreation-conservation nexus, and need for timely impact assessments across the social-ecological spectrum after physical environment changes -- all highly transferable principles for other natural hazard and disaster recovery settings worldwide.
Preprint
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After New Zealand's 7.8 Mw Kaikōura earthquake in late 2016 an unexpected anthropogenic effect involved increased motorised vehicle access to beaches. We show how these effects were generated by landscape reconfiguration associated with coastal uplift and widening of high-tide beaches, and present analyses of the distribution of natural environment values in relation to vehicle movements and impacts. Access changes led to extensive vehicle tracking in remote areas that had previously been protected by natural barriers. New dunes formed seaward of old dunes and have statutory protection as threatened ecosystems, yet are affected by vehicle traffic. Nesting grounds of nationally vulnerable banded dotterel ( Charadrius bicinctus bicinctus ) co-occur with vehicle tracking. An artificial nest experiment showed that vehicle strikes pose risks to nesting success, with 91% and 83% of nests destroyed in high and moderate-traffic areas, respectively, despite an increase in suitable habitat. Despite gains for recreational vehicle users there are serious trade-offs with environmental values subject to legal protection and associated responsibilities for management authorities. In theory, a combination of low-impact vehicle access and environmental protection could generate win-win outcomes from the landscape changes, but is difficult to achieve in practice. Detailed information on sensitive areas would be required to inform designated vehicle routes as a potential solution, and such sensitivities are widespread. Alternatively, vehicle access areas that accommodate longstanding activities such as boat launching could be formally established using identified boundaries to control impacts further afield. Difficulties for the enforcement of regulatory measures in remote areas also suggest a need for motivational strategies that incentivise low-impact behaviours. We discuss options for user groups to voluntarily reduce their impacts, the importance of interactions at the recreation-conservation nexus, and need for timely impact assessments across the social-ecological spectrum after physical environment changes -- all highly transferable principles for other natural hazard and disaster recovery settings worldwide.
Article
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Major ecological disturbance events can provide opportunities to assess multispecies responses to upheaval. In particular, catastrophic disturbances that regionally extirpate habitat-forming species can potentially influence the genetic diversity of large numbers of co-distributed taxa. However, due to the rarity of such disturbance events over ecological timeframes, the genetic dynamics of multispecies recolonization processes have remained little understood. Here we use single nucleotide polymorphism (SNP) data from multiple coastal species to track the dynamics of co-colonization events in response to ancient earthquake disturbance in southern New Zealand. Specifically, we use a comparative phylogeographic approach to understand the extent to which epifauna (with varying ecological associations with their macroalgal hosts) share comparable spatial and temporal recolonization patterns. Our study reveals concordant disturbance-related phylogeographic breaks in two intertidal macroalgal species along with two associated epibiotic species (a chiton and an isopod). By contrast, two co-distributed species, one of which is an epibiotic amphipod and the other a subtidal macroalga, show few if any genetic effects of palaeoseismic coastal uplift. Phylogeographic model selection reveals similar post-uplift recolonization routes for the epibiotic chiton and isopod and their macroalgal hosts. Additionally, co-demographic analyses support synchronous population expansions of these four phylogeographically similar taxa. Our findings indicate that coastal paleoseismic activity has driven concordant impacts on multiple codistributed species, with concerted recolonization events likely facilitated by macroalgal rafting. These results highlight that high-resolution comparative genomic data can help reconstruct concerted multispecies responses to recent ecological disturbance.
Article
Marine communities are dynamic and spatially heterogeneous. Earthquakes and tsunamis modulate the structure of marine communities at short and long-term scales. The objective of this review was to evaluate how such disturbances impact the morphodynamics of coastal areas and the dynamics and structure of marine benthic communities from soft and hard bottoms from intertidal, subtidal and deep-sea habitats. The results reveal that earthquakes and tsunamis caused mortality of algae and bivalves by dissection after coastal uplift. Changes on the vertical distribution of nematodes and coral fragmentation were also recorded. Recovery of the marine communities to pre-disturbance state occurred by migration and recolonization of impacted habitats. The meiofaunal organisms recovered quickly, while some communities recovered after three years. Information predisturbance is often lacking or covers a short temporal extent. It is important to establish long-term monitoring programs in areas where the likelihood of impact of disturbance of such magnitude is high to understand how marine communities are shaped at geological scales.
Technical Report
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The 7.8 magnitude Kaikōura earthquake in November 2016 caused extensive uplift along approximately 130 km of the north-eastern coastline of the South Island of New Zealand. This resulted in widespread mortality of marine organisms and alteration to the community structure and, in many places, the integrity of intertidal and subtidal rocky reefs. The disturbance adversely affected important taonga and habitat-forming species, such as pāua (Haliotis iris) and bull kelp (Durvillaea spp.), prompting an emergency ban on harvesting shellfish and seaweeds that is still in place. This report describes the results of nearshore reef surveys done at long-term monitoring sites between 2.5 and 3.5 years after the earthquake to assess the community structure and trajectories of recovery of rocky reef communities. A major goal of this work is to provide detailed information for underpinning informed decisions about re-opening fishery closures. The sites were first surveyed in 2017 as part of the Ministry for Primary Industries (MPI) Kaikōura Earthquake Marine Recovery Package. The new results included in this report relate to the fifth and fourth rounds of intertidal and subtidal surveys, respectively. These include (i) intertidal surveys done in November 2019 at 16 sites along the coastline between Oaro and Cape Campbell, encompassing uplift levels between approximately 0 and 6 metres; and (ii) subtidal surveys at 6 sites (2 around the Kaikōura Peninsula and 4 north of Kaikōura, in the Okiwi Bay/Waipapa Bay area) in mid-2019 and mid-2020, encompassing uplift levels between approximately 0.7 and 6 metres.
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Galaxias maculatus is a declining amphidromous fish that supports culturally-important whitebait fisheries in New Zealand and elsewhere in the Pacific. As a largely annual species, the seasonal productivity of spawning grounds has a strong influence on the availability of recruits. Spawning ground protection is urgently required to reverse historical degradation and improve prospects for the maintenance of sustainable fisheries. Although spawning habitat has been well characterised in tidal rivers where it is structured by water level changes on spring high tides, there has been no previous study of spawning in non-tidal rivermouths. We assessed seven non-tidal rivers over four months using a census survey approach to quantify spawning activity, identify environmental cues, and characterise fundamental aspects of the biogeography of spawning grounds. We report conclusive results that include a) identification of compact spawning reaches near the rivermouths, b) triggering of spawning events by periods of elevated water levels that were often of very short duration, suggesting that potential lunar cues were less important and that rapid fish movements had likely occurred within the catchment prior to spawning events, and c) consistent vertical structuring of spawning grounds above typical low-flow levels with associated horizontal translation away from the river channel, leading to increased exposure to anthropogenic stressors and associated management implications for protecting the areas concerned. These consistent patterns provide a sound basis for advancing the management of non-tidal rivermouths. Attention to flood management, vegetation control, and bankside recreational activities is required and may be assisted by quantifying spawning ground biogeography. The identification of rapid responses to environmental cues deserves further research to assess implications for floodplain connectivity management to support fish movements in emphemeral flowpaths, and as a potential source of bias in commonly-used fish survey methodologies.
Technical Report
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This report 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. 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 with vertical uplift of the coastal environment, although ongoing erosion and deposition processes are also important. In addition, interactions with human activities are important because they can exert strong influences on the reassembly of ecosystems which is a critical aspect of outcomes over the longer-term. Earthquake uplift caused widespread mortality of many coastal habitats and species (e.g., algal assemblages) that are adapted to a relatively specific set of conditions, often associated with characteristic locations in relation to the tidal range. In uplifted areas the intertidal zone has moved seaward leading to a physical widening of many beaches. This has provided greater opportunity for off-road vehicle access to the coast and has become particularly noticeable at headlands and other natural barriers that were previously impassable at high tide. Off-road vehicles pose threats to sensitive vegetation and wildlife unless appropriately managed. Achieving this is assisted by an understanding of the specific impacts of vehicle use, which in turn requires information on the location of sensitive areas. To ensure the best outcomes for earthquake recovery there is an urgent need to assess and respond to the new spatial patterns, and to make plans to avoid conflicts where possible. In our RECOVER (Reef Ecology and Coastal Values, Earthquake Recovery) project funded by the Ministry of Business, Innovation and Employment (MBIE) and supported by the Ministry for Primary Industries (MPI) we are collecting information on important conservation values and activities. Although research is continuing, this report provides findings that include mapping of indigenous dune system remnants, recruitment of the indigenous sand-binders spinifex (Spinifex sericeus) and pīngao (Ficinia spiralis) on uplifted beaches, distribution of red katipō (Latrodectus katipo) within earthquake-affected dune systems, distribution of banded dotterel / pohowera (Charadrius bicinctus bicinctus) nesting pairs to determine important areas, and spatial overlaps with vehicle tracking measurements along the coast. Available under an Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license
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Rocky shore ecology has been studied for a long time, starting with qualitative descriptions and becoming more quantitative and experimental over time. Some of the earliest manipulative experimental ecological studies were undertaken on rocky shores. Many, over time, have made considerable contributions to ecological theory, especially highlighting the importance of biological interactions at the community level. The suitability of rocky shores as convenient test systems for ecological experimentation is outlined. Here we consider contributions from rocky shores to the emerging concepts of supply-side ecology, the roles of competition, predation and grazing, disturbance and succession and positive interactions in structuring communities along environmental gradients. We then address alternative stable states, relationships between biodiversity and ecosystem functioning, and bottom-up and top-down control of ecosystems. We briefly consider the feedback and synergies between ecological concepts and experimental work on rocky shores, whilst still emphasizing the traditional values of marine natural history upheld in JMBA since its first publication. The importance of rigorous experimental designs championed by Underwood and co-workers is emphasized. Recent progress taking advantage of new technologies and emerging approaches is considered. We illustrate how experimental studies have shown the importance of biological interactions in modulating species and assemblage-level responses to climate change and informed conservation and management of coastal ecosystems.
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Catastrophic events can have profound effects on the demography of a population and consequently, on genetic diversity. The dynamics of post‐catastrophic recovery as well as the role of sexual versus asexual reproduction in buffering the effects of massive perturbations remain poorly understood, in part because the opportunity to document genetic diversity before and after such events is rare. Six natural (purely sexual) and seven cultivated (mainly clonal due to farming practices) populations of the red alga Agarophyton chilense were surveyed along the Chilean coast before, in the days after and two years after the 8.8 magnitude earthquake in 2010. The genetic diversity of sexual populations appeared sensitive to this massive perturbation, notably through the loss of rare alleles immediately after the earthquake. By 2012, the levels of diversity returned to those observed before the catastrophe, probably due to migration. In contrast, enhanced rates of clonality in cultivated populations conferred a surprising ability to buffer the instantaneous loss of diversity. After the earthquake, farmers increased the already high rate of clonality to maintain the few surviving beds, but most of them collapsed rapidly. Contrasting fates between sexual and clonal populations suggest that betting on strict clonality to sustain production is risky, probably because this extreme strategy hampered adaptation to the brutal environmental perturbation induced by the catastrophe.
Article
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The 13 November 2016 Kaikoura, New Zealand, M w 7.8 earthquake ruptured multiple crustal faults in the transpressional Marlborough and North Canterbury tectonic domains of northeastern South Island. The Hikurangi trench and underthrust Pacific slab terminate in the region south of Kaikoura, as the subdution zone transitions to the Alpine fault strike-slip regime. It is difficult to establish whether any coseismic slip occurred on the megathrust from on-land observations. The rupture generated a tsunami well recorded at tide gauges along the eastern coasts and in Chatham Islands, including a ~4 m crest-to-trough signal at Kaikoura where coastal uplift was about 1 m, and at multiple gauges in Wellington Harbor. Iterative modeling of teleseismic body waves and the regional water-level recordings establishes that two regions of seafloor motion produced the tsunami, including an M w ~7.6 rupture on the megathrust below Kaikoura and comparable size transpressional crustal faulting extending offshore near Cook Strait.
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To assess the course and status of recovery of rocky intertidal zonation after massive subsidence caused by the 2011 Great East Japan Earthquake, from 2011 to 2013 we censused the vertical distribution of 10 dominant macrobenthic species (six sessile and four mobile species) in the mid-shore zone of 23 sites along the Sanriku coastline, 150–160 km north-northwest of the earthquake epicentre, and compared the vertical distributions of each species with their vertical distributions in the pre-earthquake period. The dynamics of rocky intertidal zonation varied substantially among species. Among sessile species, one barnacle dramatically increased in abundance and expanded its vertical range in 2011, but then decreased and completely disappeared from all plots by 2013. Zonations of other sessile species shifted downward following the subsidence in 2011. With some species, there was no clear change in abundance immediately after the earthquake, but they then began to increase and move upward after a few years; with other species, abundance continuously decreased. There was no clear change in the vertical distribution of any of the mobile species immediately after the earthquake. Abundance of two mobile species was unchanged, but abundance of the others decreased from 2012 and had not recovered as of 2013.
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As climatic changes and human uses intensify, resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points, or dramatic shifts in structure and function that are often costly and hard to reverse. Evidence indicates that explicitly addressing tipping points leads to improved management outcomes. Drawing on theory and examples from marine systems, we distill a set of seven principles to guide effective management in ecosystems with tipping points, derived from the best available science. These principles are based on observations that tipping points (1) are possible everywhere, (2) are associated with intense and/or multifaceted human use, (3) may be preceded by changes in early-warning indicators, (4) may redistribute benefits among stakeholders, (5) affect the relative costs of action and inaction, (6) suggest biologically informed management targets, and (7) often require an adaptive response to monitoring. We suggest that early action to preserve system resilience is likely more practical, affordable, and effective than late action to halt or reverse a tipping point. We articulate a conceptual approach to management focused on linking management targets to thresholds, tracking early-warning signals of ecosystem instability, and stepping up investment in monitoring and mitigation as the likelihood of dramatic ecosystem change increases. This approach can simplify and economize management by allowing decision makers to capitalize on the increasing value of precise information about threshold relationships when a system is closer to tipping or by ensuring that restoration effort is sufficient to tip a system into the desired regime.
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Frameworks play an important role in analyzing social-ecological systems (SESs) because they provide shared concepts and variables that enable comparison between and accumulation of knowledge across multiple cases. One prominent SES framework focusing on local resource use has been developed by Elinor Ostrom and her colleagues. This framework is an extensive multi-tier collection of concepts and variables that have demonstrated relevance for explaining outcomes in a large number of case studies in the context of fishery, water, and forestry common-pool resources. The further development of this framework has raised a number of issues related to the formal relationships between the large number of concepts and variables involved. In particular, issues related to criteria for ordering the concepts into tiers, adding new concepts, defining outcomes metrics, and representing dynamics in the framework have been identified. We address these issues by applying methods from research fields that study formal relationships between concepts such as domain-specific languages, knowledge representation, and software engineering. We find that SES frameworks could include the following seven formal components: variables, concepts, attribution relationships, subsumption relationships, process relationships, aggregation relationships, and evaluation metrics. Applying these components to the Ostrom framework and a case study of recreational fishery, we find that they provide clear criteria for structuring concepts into tiers, defining outcome metrics, and representing dynamics. The components identified are generic, and the insights gained from this exercise may also be beneficial for the development of other SES frameworks.
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A magnitude 7.1 earthquake struck the Canterbury Region of New Zealand at 4:35 am on 4 September 2010. It was centred 11 km beneath the rural town of Darfield, on the Greendale Fault, which was previously unidentified. Christchurch City lies 40 km east of Darfield, and was home to a population of approximately 370,000 at the time of the earthquake. There was extensive damage as a result of the MM9 shaking, particularly to buildings and infrastructure, but fortunately there were no deaths. The residents began the recovery process, plagued by frequent aftershocks. Then, more than five months after the mainshock, on 22 February 2011, a M6.3 aftershock occurred 5 km south-east of Christchurch at a depth of only 5 km. This earthquake struck at lunchtime on a working day, causing catastrophic damage to the city, and resulting in 185 deaths. Most of these casualties occurred as a result of the collapse of two large office buildings, with further deaths resulting from falling bricks and masonry, and rockfalls in city suburbs. The M7.1 earthquake and associated aftershocks have caused extensive impacts on the local built, economic, social, and natural environments. The on-going aftershocks have also caused a disrupted environment in which to recover. This paper will outline the nature of the Canterbury earthquakes and provide an introduction to the ongoing effects the earthquakes have had on these local environments to help frame the growing body of research coming out of the Canterbury earthquakes.
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The devastating earthquake (moment magnitude: 8.8 MW) that struck Chile on 27 February 2010 and the following tsunami waves produced widespread damage, coastal coseismic uplifts, and large-scale mortality of rocky intertidal and shallow subtidal organisms. The effects were particularly remarkable around the Gulf of Arauco, Santa Mar a Island and the Bay of Concepcion (similar to 36 to 38 degrees S). Measurements of rocky intertidal and shallow subtidal belt-forming (biomarker) species conducted a few weeks after the earthquake indicated coastal uplifts ranging from similar to 0.2 to 3.1 m, which are similar to uplifts estimated by FitzRoy (1839; Voyages of the Adventure and Beagle, Vol. II) and Darwin (1839; Voyages of the Adventure and Beagle, Vol. III) after the 1835 Chilean earthquake. In major uplifted sites, there was massive mortality of the main intertidal and shallow subtidal belt-forming species, such as lithothamnioid melobesioid coralline algae, brown kelps and mussels, and dramatic changes in the marine rocky intertidal ecosystem. We suggest that in the southeastern Pacific, drastic and rapid coastal deformations seriously impinge on rocky shore populations, communities and ecosystems and may have significance for management and conservation practices, as for example in connection with alterations of parental stocks and recruitment rates.
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An earthquake with a dozen faults The 2016 moment magnitude ( M w ) 7.8 Kaikōura earthquake was one of the largest ever to hit New Zealand. Hamling et al. show with a new slip model that it was an incredibly complex event. Unlike most earthquakes, multiple faults ruptured to generate the ground shaking. A remarkable 12 faults ruptured overall, with the rupture jumping between faults located up to 15 km away from each other. The earthquake should motivate rethinking of certain seismic hazard models, which do not presently allow for this unusual complex rupture pattern. Science , this issue p. eaam7194
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The =7.8 Kaikoura (New Zealand) earthquake involved a remarkably complex rupture propagating in an intricate network of faults at the transition between the Alpine fault in the South Island and the Kermadec-Tonga subduction zone. We investigate the main features of this complicated rupture process using long-period seismological observations. Apparent Rayleigh-wave moment-rate functions reveal a clear northeastward directivity with an unusually weak rupture initiation during 60 s followed by a major 20 s burst of moment rate. To further explore the rupture process, we perform a Bayesian exploration of multiple point-source parameters in a 3-D Earth model. The results show that the rupture initiated as a small strike-slip rupture and propagated to the northeast, triggering large slip on both strike-slip and thrust faults. The Kaikoura earthquake is thus a rare instance in which slip on intraplate faults trigger extensive interplate thrust faulting. This clearly outlines the importance of accounting for secondary faults when assessing seismic and tsunami hazard in subduction zones.
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Processes responsible for transporting detached macroalgae through the nearshore environment and offshore to where long distance dispersal (LDD) can occur have rarely been examined. Here, we test the influence of nearshore winds, tidal currents and position of release (low, mid or high tidal zone) on the dispersal of drifting fucoid algae were tested. “Drift sets” (tagged Hormosira banksii, Durvillaea antarctica, Cystophora torulosa and GPS drifters) were tracked over single tidal cycles. Wind direction had the greatest effect on movement of drift sets, but interacted with tidal direction. Overall, offshore winds and outgoing tides were most favourable for LDD, but their effect differed between species. Approximately 90% of H. banksii, D. antarctica and GPS-tracked drifters were beach-cast after one tidal cycle during onshore winds, while 19% were beach-cast during offshore winds. In contrast, 50–75% of C. torulosa were beach-cast after one tide, regardless of wind direction. Displacement of drifters was affected by tidal zone of release, but interacted with wind and tidal direction. Drifting velocities varied between drifter types, with surface drifters travelling further and faster than the benthic-drifting species. Analysis of 20 years of wind data found seasonal differences in the percentage of hourly winds, with greater periods of south-westerly and north-westerly winds, and fewer onshore north-easterly winds, during autumn and winter periods. Conditions for successful offshore dispersal from the major algal dominated peninsulas of southern New Zealand are, therefore, more likely to occur if detachment of algae occurs during outgoing tides in autumn and winter.
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Predictions of the effects of climate change in the coastal zone require an understanding of the relationships between environmental and biotic variables. These are often highly complex and uncertain because of the many ways marine biota interact with each other under different environmental conditions. We use data collected over the past several decades to de termine changes in the key environmental variables and area-specific changes in the dominant habitat-forming macroalgae. Sea surface temperature (SST) data and wave heights from ERA-Interim reanalysis were analysed for 3 areas of the east coast of New Zealand's South Island to detect trends over the past 30 yr. We then used detailed benthic survey data acquired quarterly or half-yearly in 2 tidal zones at the same coastal areas from 1994 onwards. There were significant increases in the mean SST at 2 of the 3 areas, with average increases of 0.16°C per decade over 3 decades. Maximum SST did not increase, but the minimum seawater temperatures did, by up to 0.34°C per decade. Mean significant wave height also increased over this period by 0.06 m per decade, and maximum wave height by up to 0.3 m per decade at 2 of the 3 areas. Boosted regression tree analysis was used to determine any consistent patterns between physical variables and benthic algal cover. Generally, air temperature and the Southern Oscillation Index (SOI) were the most influential variables on cover of fucoid macroalgae. SST and wave height were also important but less influential. Fucoid cover increased with maximum air temperature beyond ca. 22 to 24°C, and cover decreased during La Niña periods at the most northern site, but increased during La Niña periods at the most southern site. The relative contributions of SST and wave height variables to the models were area- and tidal zone-specific. Overall, this study showed highly variable effects of a changing climate on an ecologically important habitat-former, highlighting the problems of dealing with ecological and climate variables that operate at differing spatial and temporal scales. We discuss this with respect to community structure and dynamics.