South Coast Of Australia Research Articles

Enhancing the performance of hybrid wave-wind energy systems through a fast and adaptive chaotic multi-objective swarm optimisation method

Hybrid offshore renewable energy platforms have been proposed to optimise power production and reduce the levelised cost of energy by integrating or co-locating several renewable technologies. One example is a hybrid wave-wind energy system that combines offshore wind turbines with wave energy converters (WECs) on a single floating foundation. The design of such systems involves multiple parameters and performance measures, making it a complex, multi-modal, and expensive optimisation problem. This paper proposes a novel, robust and effective multi-objective swarm optimisation method (DMOGWA) to provide a design solution that best compromises between maximising WEC power output and minimising the effect on wind turbine nacelle acceleration. The proposed method uses a chaotic adaptive search strategy with a dynamic archive of non-dominated solutions based on diversity to speed up the convergence rate and enhance the Pareto front quality. Furthermore, a modified exploitation technique (Discretisation Strategy) is proposed to handle the large damping and spring coefficient of the Power Take-off (PTO) search space. To evaluate the efficiency of the proposed method, we compare the DMOGWA with four well-known multi-objective swarm intelligence methods (MOPSO, MALO, MODA, and MOGWA) and four popular evolutionary multi-objective algorithms (NSGA-II, MOEA/D, SPEA-II, and PESA-II) based on four potential deployment sites on the South Coast of Australia. The optimisation results demonstrate the dominance of the DMOGWA compared with the other eight methods in terms of convergence speed and quality of solutions proposed. Furthermore, adjusting the hybrid wave-wind model’s parameters (WEC design and PTO parameters) using the proposed method (DMOGWA) leads to a considerably improved power output (average proximate boost of 138.5%) and a notable decline in wind turbine nacelle acceleration (41%) throughout the entire operational spectrum compared with the other methods. This improvement could lead to millions of dollars in additional income per year over the lifespan of hybrid offshore renewable energy platforms.

Genetic divergence of farmed blue mussels (Mytilus sp.) in Australian waters

As valuable ecosystem engineers, blue mussels, are one of the most ecologically and economically important bivalve species in Australia. The need for understanding levels of genetic diversity in both wild and farmed populations of Australian mussels is ever-growing due to the increased risk of disease and decreased fitness associated with the constantly changing global environment. This study, therefore, investigated the phylogenetic relationship, and the genetic variation of farmed blue mussels (Mytilus sp., previously noted as M. galloprovincialis, M. planulatus or a hybrid of both) at four sites along the south coast of Australia, Victoria, South Australia, Western Australia, and Tasmania. Analyses of two genes, Cytochrome c oxidase subunit 1 gene (mtCOI) and the nuclear gene Elongation factor 1 alpha (EF1a) was completed for all mussels sampled. The phylogenetic reconstruction of mtDNA sequences was not able to cluster the samples into species. The analyses of the nuclear marker (EF1a) returned similar results, except that we could conclude the Australian samples not being M. chilensis. Furthermore, the analyses of EF1a revealed the presence of hybridisation, a pattern commonly observed in mussels. The genetic diversity analysis of mtCOI demonstrated that samples from Victoria and Western Australia had the highest genetic diversity, while South Australia had the lowest. When analysing the nuclear EF1a sequences, mussels from Western Australian had the lowest genetic diversity, and the Victorian samples had the highest.The study extended our knowledge on the population genetic variation of farmed blue mussels (Mytilus sp.) along the south coast of Australia. The identified genetic differences between the four southern states of Australia could be interesting for the aquaculture industry when aiming for more adaptable and profitable stocks.

Dolphin interactions with tuna feedlots at Port Lincoln, South Australia and recommendations for minimising entanglements

Cetacean carcasses near Port Lincoln and entanglements in southern blue-fin tuna feedlots were monitored between 1990 and 1999. Dolphins became entangled and died in large-mesh (usually > 15cm) anti-predator nets around the cages, from surface to seafloor (18m). The carcasses were retrieved and studied with respect to diet and life history. During the period of study, 29 dolphins (15 bottlenose, 9 common, 5 unidentified) were confirmed entanglement deaths and an additional eight unconfirmed reports of dead dolphins were made between 1993 and 1996. Beach-washed or floating carcasses of an additional 38 dolphins were found in the Port Lincoln region during 1990-1999, four of which were suspected entanglements. The carcasses of 23 entangled and four suspected entangled dolphins were studied for diet, and reproductive and relative age characteristics. At least 24 of the 33 entangled animals were juveniles or sexually mature animals, of which most of the females were pregnant or lactating. Three calves and no neonates were entangled. Gastrointestinal contents of 57 bottlenose and common dolphins from elsewhere along the coast of South Australia were also studied. Cephalopods were more abundant in bottlenose dolphins than common dolphins, including those entangled in tuna feedlots. Carangidae were the main identified fish prey of dolphins entangled in tuna nets. The study concluded that dolphins were being attracted to, and feeding in, the area of the cages. Recommendations for minimising entanglements include removing anti-predator nets or reducing mesh size to less than 8cm, reducing tuna food wastes and thereby the food source for other fish in the vicinity, and rigorous monitoring of both entanglements and dolphin populations in the Port Lincoln region.

Variability analysis of monthly precipitation vector time series in Australia by a new spatiotemporal entropy statistic

Changing climate in Australia has significant impacts on the country’s economy, environment and social well-being. Addressing such impacts, particularly that of precipitation change, entails immediate action due to the more frequent occurrence of extreme dry or wet events in Australia in recent decades. In this paper we investigate the intra-annual Australian precipitation variability and how it changes over space and time. We quantify this variability using information entropy—a statistical tool for measuring the uncertainty of a random variable over its sample space, and propose a compositional data model to compute optimal spatiotemporal estimators of this entropy using 1/1979-to-3/2022 monthly satellite precipitation estimates from the National Oceanic and Atmospheric Administration. The results enable us to identify those locations/times where/when extreme intra-annual precipitation variation or unevenness occurred. We find this variability has been changing over time in large regions of southeastern Queensland and on the coast of South Australia, which would be difficult to find without using the proposed approach. We uncover the development of extreme entropy in the months leading up to, and in the location of, four extreme precipitation events in Australia where inter-annual precipitation amounts and/or trends proved insignificant. In marked contrast to annual precipitation, we found entropy has a weak association with the El Niño Southern Oscillation cycle.

Effects of rainfall in the arid zone on waterbird abundance at a wastewater treatment plant in coastal South Australia

We investigated which species of waterbirds at Bolivar, a wastewater treatment plant in Metropolitan Adelaide, South Australia, are likely to have been immigrants from the ephemeral wetlands in the arid zone. To do this, we compared the abundance of waterbird species observed at Bolivar during the dry period in the eastern arid zone of late 2018 and 2019 with that during the subsequent wet period 2020–2022. Pink-eared Duck Malacorhynchus membranaceus, Grey Teal Anas gracilis, Australasian Shoveler Spatula rhynchotis, Hardhead Aythya australis and Blue-billed Duck Oxyura australis were all more abundant during the arid-zone dry period. By contrast, Australian Shelduck Tadorna tadornoides, Eurasian Coot Fulica atra and Black Swan Cygnus atratus showed increased abundance in spring and early summer in all years, with no marked differences between the dry and wet periods in the arid zone. Wader species that breed in the Northern Hemisphere – Sharp-tailed Sandpiper Calidris acuminata and Red-necked Stint C. ruficollis – also tended to be more abundant during the arid-zone dry year, as did Red-necked Avocet Recurvirostra novaehollandiae, whereas Pied Stilt Himantopus leucocephalus tended to be more abundant in the arid-zone wet years, with breeding by this species taking place in spring. These data suggest that Bolivar is a critically important conservation site for waterbirds and that various species use this location as a refuge during dry times in the arid zone of eastern Australia.

Wave-By-Wave Prediction in Narrowly Spread Seas Using Fixed- and Drifting-Point Wave Records: Validation Using Physical Measurements

Abstract Accurate and reliable phase-resolved prediction of ocean surface waves is crucial for many offshore operations in ocean engineering and marine science. One important application is in optimal control of a power take-off in a wave energy converter, leading to significantly higher power production. Our interest is forecasting wave fields based on measurements obtained from multiple upwave locations in moderate seas with small directional spreading angles, as occurs along the south coast of Australia. The prediction model, based on FFTs and propagation of waves according to the linear dispersion relation, is applied to both wave groups and irregular wave fields generated in a wave basin and, additionally, to ocean waves measured with drifting wave buoys. To account for spreading, the model numerically advances linear, plane (i.e., long-crested) waves in space at an optimum offset angle equal to the underlying sea-state root mean square spreading angle. Averaging predictions from a few slightly separated measurement locations, each weighted according to its estimated variance, results in more accurate predictions than from any single location. We also assess in detail the effect of drifting buoy measurements in both long-crested and short-crested seas using synthetic wave records and show that it is possible to satisfactorily reconstruct the signal at fixed points based on the Doppler shift felt by the drifting buoy. The reconstructed signals give much better predictions compared to those completely neglecting the effect of even rather slow drift due to current.

Phase-resolved wave prediction in highly spread seas using optimised arrays of buoys

In many offshore operations, including the operation of wave energy converters, phase-resolved wave prediction is essential for safety and efficiency. However, for sea-states with large directional spreading angles, wave prediction becomes increasingly difficult. This study investigates the benefit of exploiting concurrent surface-displacement time histories measured by a buoy in three degrees of freedom (DoF) to facilitate prediction in such highly spread sea-states. A direct comparison is made with arrays of sensors measuring in a single DoF using the same formulation. The arrays considered are extensively optimised along with multiple sets of representative angles used to describe wave propagation, which is assumed to be normally distributed. The performance of the scheme is tested on a range of synthetically generated, realistic sea-states comprising single and crossing swells prevalent along the south coast of Australia. Additional tests involve wind-sea and swell waves described using Ewans models. Accurate predictions are obtained for times up to three wave periods into the future, in typical cases. With the multiple sets of optimal angles obtained for each optimal array, we further enhance the capability of the scheme by aggregating and averaging the different predictions from these sets. We observe a marked increase in both performance with large spreading and tolerance to possible variation in mean wave directions.

Prediction of the dynamic distribution for Eucheuma denticulatum (Rhodophyta, Solieriaceae) under climate change in the Indo-Pacific Ocean

Eucheuma is one of the most important commercial red seaweeds in Southeast Asia, and plays an important role in the global seaweed aquaculture. It is expected to exhibit great responses to ocean warming. Here, we used maximum entropy species distribution models (SDMs) to estimate the suitable habitat of Eucheuma denticulatum under present conditions, and to predict the future range dynamics under the four representative concentration pathway (RCP) scenarios. The best marine environmental factors for E. denticulatum distribution modeling were distance to shore, sea surface temperature and currents velocity. Our results showed that E. denticulatum’ distributions would contract in the Central Indo-Pacific Ocean, especially the regions of the Sunda Shelf, while expanding poleward along the south coast of Australia in 2100. Our study provided important knowledge for the prediction of the tropical seaweed distribution, conservation and sustainable developments of E. denticulatum in the future.

Cryptic diversity and phylogeographic patterns of the Bostrychia intricata species complex (Rhodomelaceae, Rhodophyta) along the coast of southeastern Australia

ABSTRACT Marine phylogeographic studies have recently shown that historical events, oceanography and ecological factors shape patterns of biodiversity and population connectivity. In southeastern Australia a historical geographic barrier, the Bassian Isthmus, results in deep genetic differentiation between some marine taxa. Using partial mitochondrial cytochrome oxidase subunit I (COI) DNA sequences, we investigated the genetic diversity and phylogeography among 26 populations of the red alga Bostrychia intricata along the southeastern Australian coast. Our genetic data revealed the occurrence of five cryptic B. intricata species (lineages N5, N7, N8, N9 and N10), two of which (N9 and N10) are newly discovered and endemic to Tasmania, while cryptic species N5 and N7 were confined to mainland Australia. Species N8 was more genetically diverse and extensively distributed than the other cryptic species, because it occurred both on mainland Australia and in Tasmania. We also detected a clear east–west phylogeographic break between cryptic species N7 and N5, and between haplotypes of species N8 on either side of Wilsons Promontory (the southernmost tip of mainland Australia). Spatial analysis of molecular variance identified three clusters of populations of species N8 along the south coast of Australia, and the split among these groups corresponded to extensive sandy areas: Coorong dunefield and Ninety Mile Beach. Additionally, our study detected the separation between mainland Australian (species N5 and N7) and Tasmanian species (N9 and N10) across the Bass Strait. We suggest that phylogeographic breaks and genetic differentiation in cryptic B. intricata species likely correlate to the historical Bassian land bridge, present-day habitats and different oceanographic circulation patterns.

Molecular Systematics of the Siphonous Green Algal Genus Codium in Eastern Victoria, Australia

The widely distributed genus Codium is a major component of the marine macroalgal flora and has its largest species diversity in warm-temperate regions. Along the South coast of Australia, Codium is a diverse group, but the species diversity in the easternmost region of Victoria is not well-documented. In this study, we characterized the species diversity of Codium from Croajingolong National Park, Gabo Island Lighthouse Reserve and Cape Howe Marine National Park. The specimens were collected from a wide range of microhabitats during an expedition of the Bush Blitz program, and Codium species were delimited through a combination of molecular analyses of the chloroplast markers tufA and rbcL, and morphological observations. Six species-level clusters were found, corresponding to the native C. australicum, C. harveyi, C. lucasii.1 and C. fragile subsp. novae-zelandiae; and the exotic C. fragile subsp. fragile and C. tenue. The specimens of C. australicum showed variability in the architecture of the thallus that was attributed to the different habitats where they were collected. The utricles of C. harveyi were unusual in having a thick apical cell wall that protruded inwards and had internal projections. The species found in eastern Victoria are typical of the Flindersian and Peronian biogeographic provinces, and the low diversity of Codium species in this region is comparable to that of New South Wales.

Changes in vegetation cover on the Younghusband Peninsula transgressive dunefields (Australia) 1949–2017

AbstractStudies have shown that the impact of climate change, human and animal actions on coastal vegetation can turn stabilized dunes into active mobile dunes and vice versa. Yet, the driving factors that trigger vegetation changes in coastal dunes are still not fully understood. In the transgressive dunefields of the Younghusband Peninsula (south‐east coast of South Australia) historical aerial photographs show an increase in vegetation cover over the last ~70 years. This study attempts to identify the causes of the changes in vegetation cover (1949 to 2017) observed in a typical section of the coastal dune systems of the Peninsula. Vegetation cover was first estimated for various years using the available historical aerial photography (long‐term changes – 1949 to 2017) and recent satellite imagery (short‐term annual changes – 2010 to 2017) for the area, and then results were discussed against the observed changes in climatic variables and rabbit density, factors that could have played a role in this transformation. Results of long‐term changes show that the vegetation cover has increased significantly from 1949 to 2017, from less than 7% vegetation cover to almost 40%, increasing dune stabilization and forming parabolic dune systems. Periods with the largest growth in vegetation cover (1952‐1956 and 2009‐2013) coincide with a significant decline in rabbit numbers. Rabbit density was found to be the primary factor linked to the rapid vegetation growth and stabilization of the dunefield, for both decadal long‐term (last 68 years) and annual short‐term changes (last 8 years). Other factors such as changes in rainfall, aeolian sediment transport, land use practices, and the introduction of invasive plants have apparently played a limited to negligible role in this stabilization process. © 2018 John Wiley & Sons, Ltd.

Predicting environmental suitability for key benthic species in an ecologically and economically important deep-sea environment

The Great Australian Bight (GAB) is important ecologically due to a diverse benthic fauna with high endemicity, and productivity that supports marine mammals and apex predators. The region is also economically important, supporting valuable fisheries, aquaculture and ecotourism industries. Deep-sea (>200 m depth) exploration leases for oil and gas have also recently been activated. Characterising the environment of the GAB is a priority in light of these activities, but although areas of the GAB continental shelf have been well-studied, there is a paucity of data on benthos from depths > 200 m and a virtual absence of collated benthic ecological information. Predictive ecological modelling is increasingly being used for deep-sea benthic characterisation given the large areas involved and logistic challenges of sampling these environments. For example, species distribution models can be used to predict environmental suitability in unsampled areas, and to inform spatial management for data-poor regions. We explored options and selected the maximum likelihood implementation of the popular MaxEnt method to predict environmental suitability for 96 deep-water benthic species across temperate Australia. Occurrence records were obtained from a collation of historical museum records, online databases and recent sampling in the GAB at 200–3000 m. Aggregated predictions were used to identify patterns of suitability across species. The GAB continental slope had high relative suitability across all modelled species, particularly in the phyla Chordata and Cnidaria, while predicted suitability for species in the phyla Mollusca and Arthropoda was generally higher on the east than south coast of Australia. These patterns were influenced by the suite of species used; we found predicted suitability within the GAB to be negatively influenced by the proportion of east coast records per species. Average bottom temperature, which correlated with depth and a range of water quality variables, was the most important environmental predictor of suitability. The currently poorly-sampled upper mid-slope depths (500–800 m) of the GAB had the greatest predicted suitability across the suite of modelled species; hence recent sampling of the GAB benthos may have underestimated benthic faunal abundance and diversity in this region.

Variance in the response of silcrete to rapid heating complicates assumptions about past heat treatment methods

Heat treatment of silcretes in the Middle Stone Age of southern Africa has been taken to indicate complex behaviour among early modern humans. This inference is based on the apparent sensitivity of silcretes to rapid changes in temperature, requiring well-regulated heating and cooling rates, and controls over maximum heating temperatures. Alternative arguments have been made that silcrete can effectively be heat treated with limited control over heating rates such that heat treatment may have been a relatively simple process. These apparently contrasting points of view elide the fact that different silcretes may respond differently to heating, and that no single approach may be appropriate in all cases. To test this proposition, we undertook a series of controlled experiments in which silcrete from two sources on the south coast of Australia were prepared into blocks of specific sizes and heated rapidly to a range of maximum temperatures in a muffle furnace. In addition to potential differences in response between sources to heat, our experiments test two factors—stone volume and maximum heating temperature—that were advanced by past explanatory models to account for the probability of sample failure (fracture) during heating. The results of our experiments suggest that the tolerance of silcretes to high heating rates is highly variable between sources within regions, and that the effect of variation between sources is stronger than the other factors examined. Additional tests on limited samples from sources in South Africa support the general relevance of our findings. From these results, we infer that optimal approaches to heating in the past were probably sensitive to the silcretes being heated.

Mychodea and the Mychodeaceae (Gigartinales, Rhodophyta) revisited: molecular analyses shed light on interspecies relationships in Australia’s largest endemic algal genus and family

The red algal genus Mychodea Hook.f. & Harv. is not only Australia’s largest wholly endemic macroalgal genus, it and the family Mychodeaceae (of which it is the sole member) appear to be the largest completely endemic algal genus and family from any continental landmass in the world. Kraft’s 1978 morpho-taxonomic monograph credited Mychodea with 11 species varyingly distributed between Geraldton, Western Australia, south and eastward across the coasts of South Australia, Victoria and Tasmania, and northwards into southern New South Wales. Dismissed or discounted was every former extra-Australian attribution of the genus. In the over 40 years since completion of the research, further explorations of marine habitats in Australia have uncovered additional species, and the application of molecular-assisted taxonomic and phylogenetic methodologies has now allowed a substantial refinement of Mychodea systematics. We here document 19 Mychodea species, for 16 of which we have molecular data that support inferences of probable species relationships. To the 11 species treated by Kraft we now add 4 that are recently discovered, resurrect 2 that were synonymised with a third species in his 1978 work, and treat 2 species-level Western Australian entities that remain unnamed for lack of sufficient reproductive material. Mychodea is characterised by elaborate vegetative structures and some of the most complex fertilisation, diploidisation and embryogenesis processes of any red alga, which we detail and illustrate. Distinguishing features of the individual species are highlighted, some of which are particularly unusual.

Interspecies co-use of southern hairy-nosed wombat (Lasiorhinus latifrons) burrows

Burrows can provide refuge for both burrowing and non-burrowing species within harsh environments through protection from climatic extremes, water loss and predation. In Australia, however, despite having a rich diversity of burrowing mammals, little is known about the use of burrows by non-burrowing species. This study aimed to identify the extent of co-use of southern hairy-nosed wombat (Lasiorhinus latifrons) burrows on Wedge Island off the coast of South Australia. Burrow use was monitored using 34 motion-activated cameras placed outside wombat burrows between March and September 2015. Eleven species were found to use burrows, with six commensal species observed using burrows on numerous occasions. These included two mammal species (black-footed rock-wallaby, Petrogale lateralis pearsoni; brush-tailed bettong, Bettongia penicillata), three reptile species (peninsula dragon, Ctenophorus fionni; southern sand-skink, Liopholis multiscutata; White’s skink, Liopholis whitii), and one avian species (little penguin, Eudyptula minor). The most common species observed using burrows was the black-footed rock-wallaby, which was recorded using burrows 1795 times. Observations of wombats using burrows were made 1674 times. The prevalent use of burrows on Wedge Island by species other than wombats is an observation with potentially important and broad ecological, conservation, and management implications across Australia’s arid and semiarid zones.

Breeding Biology of Australian Pelicans (Pelecanus conspicillatus) on the Coast of South Australia

The breeding biology of Australian Pelicans (Pelecanus conspicillatus) was studied on the coast of South Australia between 2002 and 2004. This study aimed to compare breeding on the coast with previous studies of inland breeding Australian Pelicans and to test whether this species exhibits siblicidal brood reduction. Nests were generally constructed on the ground in spatially and temporally discrete colonies. Nests within colonies were 1.3 ± 0.5 m apart (Range = 0.6–4.5; n = 327), whereas colonies were 329 m apart (Range = 21–1,136; n = 63). Within colonies, 80% of nests were initiated within 10 days of each other. Colonies contained 41.0 ± 37.6 nests (Range = 1–148; n = 63). Most colonies were initiated during the austral winter and spring (June–September) in contrast to opportunistic breeding in inland areas. Clutch size averaged 1.92 ± 0.36 eggs (Range = 1–4; n = 2,297), and incubation lasted 32 days (Range = 28–38; n = 57). Hatching success averaged 41.5 ± 38.6% (Range = 0–99; n = 24 colonies), the number of nestlings that survived to join a crèche was 20.3 ± 22.4% (Range = 0–66; n = 24 colonies), and fledging success averaged 15.3 ± 18.3% (Range = 0–61; n = 24 colonies). Aggression among nestlings and resulting wounds were observed in 48% of broods (n = 64). Mortality during the 10-day nestling period was high (5.5 ± 2.2%/day; Range = 2.5–10.0; n = 45) and was the major determinant of overall breeding success. These findings suggest that Australian Pelicans exhibit siblicidal brood reduction.

Learning and local government in coastal South Australia: towards a community of practice framework for adapting to global change

Social learning can be a vital tool in assisting communities to adapt to change. Local governments can be a conduit between the communities they serve and the policy that they are trying to implement. Social learning in this context can be an iterative, often organic process. Based on a case study of coastal planning in South Australia, Australia, this paper presents the results of a qualitative mixed-method approach that documents the aspects of social learning within coastal management and evaluates the various lessons learned by local governments in South Australia. The role of social learning and adaptive governance is discussed. The paper concludes that by deliberatively incorporating the notion of communities of practice into learning frameworks, local governments can more effectively manage their coastal zones in response to global change.

Australia’s War against Rabbits: The Story of Rabbit Haemorrhagic Disease

In Australia’s War against Rabbits, Brian Cooke details the emergence of rabbit hemorrhagic disease (RHD) in Asia and Europe and subsequent efforts to introduce RHD virus into Australia and New Zealand for rabbit control in the 1990s. The book documents the ecologic adaption between a virus and its animal host and provides cogent examples of our inability to contain the spread of (what was thought to be) a well-understood virus after it escaped into the environment. The first failed containment effort ensued after the virus jumped from a quarantine compound on Wardang Island to the coast of South Australia 3 km away. Despite a program carefully designed to counter unplanned spread of RHD virus on the Australian mainland (Operation Garter), the virus prevailed. Uncontained spread also followed an intentional and illegal release of RHD virus in New Zealand in 1997 when a farmer with intractable rabbit problems allegedly smuggled the virus in from Australia. After the outbreak started, instead of helping the New Zealand government control RHD, farmers reportedly used blenders to make “rabbit smoothies” and actively spread RHD virus by applying these slurries to carrot baits. The book is generally well written and heavily referenced and contains many anecdotes penned by a scientist obviously passionate about his work. The flow of the narrative can sometimes be erratic, however, veering from amusing personal stories to a didactic recounting of the taxonomy of rabbit parasites or legislation relevant to pest control in Australia. Australia’s War against Rabbits is best suited for professionals with a keen interest in rabbits, fleas, and their pathogens.

Two new species of Lysianassidae Dana, 1849 from Australia: Riwo zeidleri and Socarnella delectabilis (Crustacea: Peracarida: Amphipoda).

The new species Riwo zeidleri and Socarnella delectabilis are described. Prior to this study Riwo Lowry & Stoddart, 1995 was a monotypic genus, while Socarnella Walker, 1904 consisted of only two described species. The distribution of Riwo is expanded southwards from northern Papua New Guinea and the Great Barrier Reef to the south coast of Australia and the distribution of Socarnella is expanded further southward from Sri Lanka and the South China Sea, to the west coast of Australia.

Improving transferability of introduced species' distribution models: new tools to forecast the spread of a highly invasive seaweed.

The utility of species distribution models for applications in invasion and global change biology is critically dependent on their transferability between regions or points in time, respectively. We introduce two methods that aim to improve the transferability of presence-only models: density-based occurrence thinning and performance-based predictor selection. We evaluate the effect of these methods along with the impact of the choice of model complexity and geographic background on the transferability of a species distribution model between geographic regions. Our multifactorial experiment focuses on the notorious invasive seaweed Caulerpacylindracea (previously Caulerpa racemosa var. cylindracea ) and uses Maxent, a commonly used presence-only modeling technique. We show that model transferability is markedly improved by appropriate predictor selection, with occurrence thinning, model complexity and background choice having relatively minor effects. The data shows that, if available, occurrence records from the native and invaded regions should be combined as this leads to models with high predictive power while reducing the sensitivity to choices made in the modeling process. The inferred distribution model of Caulerpacylindracea shows the potential for this species to further spread along the coasts of Western Europe, western Africa and the south coast of Australia.