Solitary Islands Research Articles

Are corals coming to a reef near you? Projected extension of suitable thermal conditions for hard coral communities along the east Australian coast

AbstractClimate change is driving the poleward redistribution of coral species, but the rate and magnitude of future range extensions within temperate regions are rarely quantified. A better understanding of the likely future distribution of corals is needed to anticipate the resulting social, economic and environmental implications. Here, we project the rate and magnitude of extensions of suitable thermal conditions for hard coral communities along the east Australian coastline, using data on coral community presence, in conjunction with historical and projected ocean temperatures. Our projections indicate that temperatures will be suitable for coral communities dominated by the subtropical coral Pocillopora aliciae, currently found off Sydney, to extend their range poleward by 80 (RCP 2.6) to 450 km (RCP 8.5) by 2100, corresponding to a rate of 0.9–5.0 km year−1. Similarly, thermal conditions will be such that diverse coral communities, such as those currently occurring in the Solitary Islands, may extend their range by 130 (RCP 2.6) to 580 km (RCP 8.5) by 2100, at a rate of 1.4–6.4 km year−1. These projections are similar to those forecast for coral species in other parts of the world. Newly establishing coral communities in temperate regions may provide a range of novel local economic opportunities, particularly for marine tourism.

Response in water qualities of mountain streams during low-water runoff to wet deposition load on solitary islands and high mountains facing the Sea of Japan and the East China Sea

Response in water qualities of mountain streams during low-water runoff to wet deposition load on solitary islands and high mountains facing the Sea of Japan and the East China Sea

Pesticide occurrence in an agriculturally intensive and ecologically important coastal aquatic system in Australia

Coastal agricultural practices are often located in catchments upstream of ecologically important aquatic systems. Here, we investigate the occurrence of pesticides in a coastal creek flowing into a habitat-protected area within the Solitary Islands Marine Park, Australia. Water samples were collected from six sites along a creek transect during three sampling periods. Samples were analysed for 171 pesticide analytes, including organochlorines, organophosphates, herbicides, and fungicides. Five insecticides, two herbicides, and two fungicides were detected. The neonicotinoid imidacloprid was detected at 5 out of 6 sites, with concentrations reaching 294 μg L−1, the highest yet detected in Australian waterways. The organophosphate insecticide dimethoate was detected at 4 sites, which occurred at the 2nd highest detected concentration in the study (12.8 μg L−1). The presence of these pesticides in the aquatic environment downstream of horticulture in this and other regions may have serious implications for stream biota and ecologically important marine ecosystems.

A new hermit crab of the genus Calcinus from Rapa Island, French Polynesia with affinities to Calcinus dapsiles Morgan, 1989 and Calcinus sirius Morgan, 1991 (Decapoda: Anomura: Diogenidae)

A new hermit crab of the genus Calcinus Dana, 1851 is described from a specimen collected at a depth of 100 m near Rapa Island, Austral Islands, French Polynesia. In a previous report, we had reported this specimen provisionally as Calcinus aff. sirius, pending availability of live color data for Calcinus sirius Morgan, 1991. Recently obtained color photographs of live C. sirius from the Solitary Islands, Eastern Australia, has shown that the specimen from Rapa Island is distinct from Morgan’s taxon and represents a new species which is fully illustrated and described herein as Calcinus shawi sp. nov. The morphology and coloration of this new species are compared with the closely allied C. sirius and Calcinus dapsiles Morgan, 1989.

No evidence for tropicalization of coral assemblages in a subtropical climate change hot spot

Climate change is causing the distribution and abundance of many organisms to change. In particular, organisms typical of the tropics are increasing in abundance in many subtropical regions, a process known as tropicalization. Here, we examine changes in coral abundance and assemblage structure in the Solitary Islands Marine Park (SIMP), over a 23-year period between 1990 and 2013–14. Total coral cover decreased at all six islands sampled with a concomitant decline in total coral cover at the regional scale (i.e. between sampling occasions). When coral taxa were classified as either cosmopolitan or subtropical, cosmopolitan corals decreased in cover at the regional scale. In contrast, subtropical coral cover did not change at the regional scale because large increases in cover at some islands, such as North Solitary Island, were matched by decreases at other islands. Of 16 common coral taxa examined at the regional level, one declined and two increased in cover with no change in the remaining 13 taxa. In particular, there was no increase in the abundance of coral taxa typically associated with tropical reefs. Similarly, multivariate analyses of coral assemblage structure using these 16 common taxa indicated changes in two of the six island assemblages but, again, provided no evidence for tropicalization. Modelling suggested very low probabilities of larval dispersal from the southern Great Barrier Reef to the SIMP suggesting that limited connectivity with tropical coral populations is one possible cause of the lack of tropicalization in the coral assemblages. We therefore conclude that, despite significant increases in mean sea surface temperature over the last few decades, there has been no tropicalization of the coral fauna in the SIMP. Furthermore, the small proportional reduction in total coral cover, despite the occasional incidence of coral bleaching, coral disease outbreaks and a number of large storms, suggest that the reefs of the SIMP were in reasonably good health at the time of the final survey in 2014. Our results suggest that factors other than temperature, in particular, a lack of dispersal, are limiting the expansion of tropical corals along the east coast of Australia.

Biological Sound Sources Drive Soundscape Characteristics of Two Australian Marine Parks

Soundscapes represent an intrinsic aspect of a habitat which, particularly in protected areas, should be monitored and managed to mitigate human impacts. Soundscape ecology characterizes acoustic interactions within an environment, integrating biological, anthropogenic, climatological, and geological sound sources. Monitoring soundscapes in marine protected areas is particularly important due to the reliance of many marine species on sound for biological functions, including communication and reproduction. In this study we establish a baseline understanding of underwater soundscapes within two marine National Park Zones (NPZs) along the east coast of Australia: Cod Grounds Marine Park and an NPZ surrounding Pimpernel Rock within Solitary Islands Marine Park. In each of the NPZs, underwater recorders were deployed twice during the austral winter (33–35 days, 2018 and 60–69 days, 2019) and once during the austral summer (35–71 days, 2018–2019). We used the resulting acoustic recordings to determine hourly presence of anthropogenic and biological sounds between 20 Hz and 24 kHz and analyze their contributions to patterns of received sound levels. Sounds from vessels were recorded on most days throughout monitoring but were not found to influence long-term patterns of sound levels over their corresponding frequencies. Biological sources included dolphins, snapping shrimp, fish choruses, humpback whales, and dwarf minke whales. Dolphins, snapping shrimp, and fish choruses were present in all deployments. Median ambient sound levels showed a consistent diel pattern with increased levels resulting from crepuscular fish choruses combined with a higher intensity of snapping shrimp snaps during those times. Singing humpback whales strongly influenced the overall sound levels throughout the winter migration, while dwarf minke whales were consistently detected in the 2019 winter deployment but were only present in 2 h among the earlier deployments. Patterns of acoustic spectra were similar between the two NPZs, and patterns of soundscape measurements were observed to be driven by seasonal differences in biological contributions rather than anthropogenic sound sources, indicating that these NPZs are not yet heavily impacted by anthropogenic noise. These baseline measurements will prove invaluable in long-term monitoring of the biological health of NPZs.

High biomass and productivity of epifaunal invertebrates living amongst dead coral

Climate change is transforming coral reef structures, with important yet largely unknown consequences for reef food webs. Crustaceans, molluscs, polychaetes, and other small motile invertebrates living as epifauna on coral habitats represent an essential trophic link between primary producers and a diverse and abundant invertivorous fish fauna. Here, we investigate variation in assemblages of motile epifaunal invertebrates on live coral and dead coral heavily overgrown by turf algae. Sampling was conducted 2–3 years following mass bleaching within the study region at four locations broadly spanning the distribution of corals on the eastern seaboard of Australia—along the northern and central Great Barrier Reef, and, adjacent to the central east coast, the Solitary Islands and offshore Elizabeth and Middleton Reefs (> 2000 km total distance). Epifaunal assemblages differed significantly between live and dead ‘turf-covered’ coral habitats, with overall density, biomass, and productivity of epifauna more than an order of magnitude greater on dead than on live coral. The size structure and composition of assemblages also differed: turf-covered dead coral supported greater abundances of small animals than live coral, notably harpacticoid copepods, while live coral assemblages had proportionally greater abundances of larger decapods. A ten-fold increase in secondary productivity of motile invertebrates is predicted as live corals are replaced by turf-covered dead coral, however, this productivity will predominantly be available as small harpacticoid copepod prey (size range: 0.125–0.25 mm). Associated flow-on effects through reef food webs are likely, as changes to epifauna will directly affect invertivore communities, which in turn potentially influence larger carnivores and other functional groups.

Linking population size structure, heat stress and bleaching responses in a subtropical endemic coral

Anthropocene coral reefs are faced with increasingly severe marine heatwaves and mass coral bleaching mortality events. The ensuing demographic changes to coral assemblages can have long-term impacts on reef community organisation. Thus, understanding the dynamics of subtropical scleractinian coral populations is essential to predict their recovery or extinction post-disturbance. Here we present a 10-yr demographic assessment of a subtropical endemic coral, Pocillopora aliciae (Schmidt-Roach et al. in Zootaxa 3626:576–582, 2013) from the Solitary Islands Marine Park, eastern Australia, paired with long-term temperature records. These coral populations are regularly affected by storms, undergo seasonal thermal variability, and are increasingly impacted by severe marine heatwaves. We examined the demographic processes governing the persistence of these populations using inference from size-frequency distributions based on log-transformed planar area measurements of 7196 coral colonies. Specifically, the size-frequency distribution mean, coefficient of variation, skewness, kurtosis, and coral density were applied to describe population dynamics. Generalised Linear Mixed Effects Models were used to determine temporal trends and test demographic responses to heat stress. Temporal variation in size-frequency distributions revealed various population processes, from recruitment pulses and cohort growth, to bleaching impacts and temperature dependencies. Sporadic recruitment pulses likely support population persistence, illustrated in 2010 by strong positively skewed size-frequency distributions and the highest density of juvenile corals measured during the study. Increasing mean colony size over the following 6 yr indicates further cohort growth of these recruits. Severe heat stress in 2016 resulted in mass bleaching mortality and a 51% decline in coral density. Moderate heat stress in the following years was associated with suppressed P. aliciae recruitment and a lack of early recovery, marked by an exponential decrease of juvenile density (i.e. recruitment) with increasing heat stress. Here, population reliance on sporadic recruitment and susceptibility to heat stress underpin the vulnerability of subtropical coral assemblages to climate change.

セアラ・オーン・ジュエットの『とんがり樅の木の郷』における孤独と孤島 点と点をつなぐ作家

セアラ・オーン・ジュエットの『とんがり樅の木の郷』における孤独と孤島 点と点をつなぐ作家

The projected degradation of subtropical coral assemblages by recurrent thermal stress.

Subtropical coral assemblages are threatened by similar extreme thermal stress events to their tropical counterparts. Yet, the mid- and long-term thermal stress responses of corals in subtropical environments remain largely unquantified, limiting our capacity to predict their future viability. The annual survival, growth and recruitment of 311 individual corals within the Solitary Islands Marine Park (Australia) was recorded over a 3-year period (2016-2018), including the 2015/2016 thermal stress event. These data were used to parameterise integral projection models quantifying the effect of thermal stress within a subtropical coral assemblage. Stochastic simulations were also applied to evaluate the implications of recurrent thermal stress scenarios predicted by four different Representative Concentration Pathways. We report differential shifts in population growth rates (λ) among coral populations during both stress and non-stress periods, confirming contrasting bleaching responses among taxa. However, even during non-stress periods, the observed dynamics for all taxa were unable to maintain current community composition, highlighting the need for external recruitment sources to support the community structure. Across all coral taxa, projected stochastic growth rates (λs ) were found to be lowest under higher emissions scenarios. Correspondingly, predicted increases in recurrent thermal stress regimes may accelerate the loss of coral coverage, species diversity and structural complexity within subtropical regions. We suggest that these trends are primarily due to the susceptibility of subtropical specialists and endemic species, such as Pocillopora aliciae, to thermal stress. Similarly, the viability of many tropical coral populations at higher latitudes is highly dependent on the persistence of up-current tropical systems. As such, the inherent dynamics of subtropical coral populations appear unable to support their future persistence under unprecedented thermal disturbance scenarios.

Luminescence of Spatially Ordered Self-Assembled Solitary Ge(Si) Nanoislands and their Groups Incorporated into Photonic Crystals

The luminescence properties of arrays of spatially ordered self-assembled solitary Ge(Si) nanoislands and their groups, including those embedded in two-dimensional photonic crystals, are studied. It is shown that the incorporation of an array of ordered solitary Ge(Si) islands and their groups into photonic crystals results in an increase in the intensity of their photoluminescence signal at liquid-nitrogen temperature. The maximum increase in the intensity (by a factor of up to ~30) is observed for an ordered array of solitary Ge(Si) islands. The increase in the intensity is attributed to the interaction of emission from islands with photonic-crystal radiative modes. This interaction is more efficient in the case of an array of solitary islands. Due to such interaction the luminescence signal from ordered solitary Ge(Si) islands incorporated into photonic crystals is observed at up to room temperature.

Sleuthing with sound: Understanding vessel activity in marine protected areas using passive acoustic monitoring

Monitoring compliance and enforcing laws are integral to ensuring the success of marine protected areas (MPAs), but traditional monitoring techniques are costly and resource demanding. Three SoundTrap 300 recorders were deployed for one month between 1 July and September 12, 2018 to collect acoustic data in two marine parks off southeastern Australia: one recorder in Cod Grounds Marine Park (CGMP) and two in the Solitary Islands Marine Park National Park Zone (SIMP NPZ). Extractive activities such as fishing are not permitted in these zones. Raven Pro 2.0 was used to analyze data for vessel presence. Transmission loss equations for each site were generated using patrol boat GPS tracks and used to predict if acoustically recorded vessels were inside park boundaries based on received sound levels. In CGMP, 41 vessels were predicted within the park during the recording period; 34 vessels were predicted within the SIMP NPZ. Thursdays and Saturdays were identified as peak days for vessel presence in CGMP while Thursdays were the peak day in the SIMP NPZ. Most vessel activity at both locations took place between 06:00 and 17:00 AEST. Peak vessel presence in CGMP occurred at 09:00 AEST while the peak vessel presence in the SIMP NPZ occurred at 16:00 AEST. Approximately 12.7 h of vessel sounds were recorded within CGMP; approximately 3.8 h of vessel noise were recorded within the SIMP NPZ. Passive acoustic monitoring of vessel patterns in Australian Marine Parks has provided valuable insight to redirect compliance decisions on how to focus surveillance efforts.

離島に所在する医療機関で勤務する看護師の，赴任後の戸惑いや困難を乗り越えるまでの過程 ― 異文化適応への示唆を求めて ―

離島に所在する医療機関で勤務する看護師の，赴任後の戸惑いや困難を乗り越えるまでの過程 ― 異文化適応への示唆を求めて ―

The shelled gastropods of the Solitary Islands Marine Park, northern New South Wales, Australia

ABSTRACTAway from the major population centres, the biodiversity of Australia's shallow coastal marine waters is poorly known. The Tweed-Moreton Bioregion, covering northern New South Wales and south-east Queensland, is both a focus of marine conservation (with three marine parks), and research efforts to predict the effects of climate change through species range extensions and shifts in community composition. Here we provide the first comprehensive list of shallow-water (<30 m) shelled, gastropod macro-molluscs (>5 mm) from the Solitary Islands Marine Park, compiled from a range of sources, including field collections over a 30-year period to 2017. The Cypraeidae (50 spp.), Muricidae (47 spp.) and Conidae (32 spp.) were the most speciose families, accounting for 26% of the total inventory of 500 species from 77 families. A total of 143 species are recorded at their southern limit of distribution on Australia's east coast, most being rare, tropically affiliated taxa found at offshore island sites that receive more frequent contact with the southward-flowing East Australian Current. The inventory confirms the high biodiversity of the Solitary Islands region and the importance of ongoing conservation management.

Partial protection disallowing trawling has conservation benefits in a subtropical marine park

Multiple-use Marine Protected Areas are typically predominantly zoned for partial protection, allowing ‘acceptable’ exploitation activities. However, biotic responses to Partially Protected Areas (PPAs) are varied, and the effectiveness of this approach in relation to management objectives can be ambiguous. Few studies have compared different levels of partial protection to provide insight into this issue. Using remote underwater video methods (stereo baited video, drop-camera) we compared fish and invertebrate assemblages between two PPA types with differing levels of protection (Habitat Protection - HP; and General Use - GU) on unconsolidated substrata in the subtropical Solitary Islands Marine Park, Australia. While both Management Types are fished, trawling is only allowed in GU. Despite high levels of spatial variation across the scales of investigation, we found fish and invertebrate assemblages differed significantly between the two Management Types. The abundance of two fish taxa and low-mobility and sessile benthic macro-invertebrates, and the mean size of the commercially targeted bluespotted flathead Platycephalus caeruleopunctatus, were each significantly greater in the un-trawled HP. Contrary to expectations, abundance of a conspicuous habitat former (pennatulacean seapens) and elasmobranchs did not differ significantly between Management Types. While unconsolidated sedimentary habitats are more homogenous than reef, our study revealed high assemblage diversity at a range of scales. Although assemblages and some individual taxa benefitted from a higher level of partial protection, the broader merit of this management approach remains unclear. Globally, PPA benefits likely depend on social, regulatory, environmental, and site-specific ecological factors.

東シナ海・日本海側の湿性沈着物負荷と高山・離島渓流群水質の関係

東シナ海・日本海側の湿性沈着物負荷と高山・離島渓流群水質の関係

Techniques for Classifying Seabed Morphology and Composition on a Subtropical-Temperate Continental Shelf

In 2017, the New South Wales (NSW) Office of Environment and Heritage (OEH) initiated a state-wide mapping program, SeaBed NSW, which systematically acquires high-resolution (2–5 m cell size) multibeam echosounder (MBES) and marine LiDAR data along more than 2000 km of the subtropical-to-temperate southeast Australian continental shelf. This program considerably expands upon existing efforts by OEH to date, which have mapped approximately 15% of NSW waters with these technologies. The delivery of high volumes of new data, together with the vast repository of existing data, highlights the need for a standardised, automated approach to classify seabed data. Here we present a methodological approach with new procedures to semi-automate the classification of high-resolution bathymetry and intensity (backscatter and reflectivity) data into a suite of data products including classifications of seabed morphology (landforms) and composition (substrates, habitats, geomorphology). These methodologies are applied to two case study areas representing newer (Wollongong, NSW) and older (South Solitary Islands, NSW) MBES datasets to assess the transferability of classification techniques across input data of varied quality. The suite of seabed classifications produced by this study provide fundamental baseline data on seabed shape, complexity, and composition which will inform regional risk assessments and provide insights into biodiversity and geodiversity.

Strong fish assemblage patterns persist over sixteen years in a warming marine park, even with tropical shifts

Spatial conservation plans representing existing patterns of biodiversity in Marine Protected Areas (MPAs) should be robust to changes over 10 to 20 years, a temporal scale over which MPA plans are often retained. Using data from MPAs where changes have been detected due to ocean warming, can help inform discussion on how to increase temporal robustness in planning. Our aim was to determine how well fish assemblage patterns, used to develop a Habitat Classification System (HCS) as a coarse biodiversity surrogate in MPA planning, persisted over a 16 year timeframe in a warming region (east coast subtropics) of Australia. We analysed persistence/change in fish assemblage patterns in the Solitary Islands Marine Park (SIMP) where species shifts and habitat changes associated with ocean warming have been detected. Fish relative abundance was recorded at 12 sites over 16 years (2001–2017) using roving timed counts. Strong cross-shelf patterns were maintained over that 16 year period, which included some large-scale disturbances (destructive storms, 2016 mass coral bleaching event). Overall persistence in these broad assemblage patterns suggest a well-designed HCS can be a robust tool for coarsely representing biodiversity patterns in a warming world at decadal scales. ‘Tropicalisation’ was detected in some categories, suggesting additional planning strategies are needed within those and beyond decadal plans.

Targeted fishes are larger and more abundant in ‘no-take’ areas in a subtropical marine park

The influence of ‘no take’ Marine Protected Areas (MPAs) on abundance and size of fishes varies considerably and the likely benefits are still debated. Meta-analyses reveal findings are biased towards studies in shallower depths suitable for diving surveys. Empirical comparisons in deeper waters, including among areas with differing spatial management, further contribute to understanding of MPA benefits and constraints. We compare length and abundance of commercially and recreationally targeted fishes (and bycatch) among management types within and adjacent to the Solitary Islands Marine Park (SIMP), Australia. Sampling was done on reefs between 25 and 40 m depth in ‘no-take’ and fished ‘partially protected’ areas within the marine park and fished areas outside the SIMP, using stereo- Baited Remote Underwater Videos (stereo-BRUVs) at eight, nine, thirteen and fourteen years after these ‘no take’ areas were established. Four species targeted by fishers: snapper Chrysophrys auratus, grey morwong Nemadactylus douglasi, pearl perch Glaucosoma scapulare, and venus-tuskfish Choerodon venustus, were more abundant and larger in ‘no take’ zones overall and showed an increase through time in ‘no take’ relative to both types of fished area. In contrast, there was no distinct pattern of four bycatch species increasing in abundance in ‘no-take’ areas. Abundances of fish in partially protected areas were similar to fished areas outside the MPA. This study adds empirical evidence to the assertion that ‘no take’ areas in particular, can contribute to both marine conservation and natural resource management.

A new method for the accurate measurement of higher-order frequency response functions of nonlinear structural systems

Higher-order frequency response functions (FRFs) are important to the analysis and identification of structural nonlinearities. Though much research effort has been devoted recently to their potential applications, practical issues concerning the difficulty and accuracy of higher-order FRF measurement have not been rigorously assessed to date. This paper presents a new method for the accurate measurement of higher-order FRFs. The method is developed based on sinusoidal input, which is ideal for exciting a nonlinear structure into desired regimes with flexible control, and the correlation technique, which is a novel signal processing method capable of extracting accurate frequency components present in general nonlinear responses. The correlation technique adopted is a major improvement over Fourier transform based existing methods since it eliminates leakage and aliasing errors altogether and proves to be extremely robust in the presence of measurement noise. Extensive numerical case studies have been carried out to critically assess the capability and accuracy of the proposed method and the results achieved are indeed very promising. Interesting nonlinear behavior such as frequency shift and jump have been observed in first-, second- and third-order FRFs, as well as solitary islands which have been identified over which higher-order FRFs virtually do not change as input force amplitude varies. Higher-order FRFs over such solitary islands are essentially their theoretical counterparts of Volterra transfer functions which can be measured with very low input force and can be profitably employed for the identification of physical parameters of structural nonlinearities. Subsequently, a nonlinear parameter identification method has also been developed using measured higher-order FRFs and results are presented and discussed.