The effects of ash from controlled fires on macroinvertebrate communities in UK headwater streams were investigated experimentally by depositing ash onto natural stream substrata in trays placed on streambeds. Ash deposition together with stream depth altered macroinvertebrate community composition. However, changes in species composition caused by ash deposition were smaller than differences among streams, suggesting that effects of ash may be small in these streams.
Marine & Freshwater Research
MF16049Assessing sea level-rise risks to coastal floodplains in the Kakadu Region, northern Australia, using a tidally driven hydrodynamic model
The coastal floodplains of the Kakadu Region of northern Australia are highly vulnerable to future sea level rise (SLR) and extreme weather events. A hydrodynamic model was developed to simulate the frequency and extent of saltwater inundation of future SLR scenarios from 2013 to 2100 (1.1 m above mean sea level), and was used to assess potential risk to freshwater floodplains.
Sediment fluxes and sinks based on total sediment load for Magela Creek in the Australian wet–dry tropics have been constructed from detailed measurements of turbidity, suspended sand and bedload for the 10-year period from 2001–2002 to 2010–2011. The present work showed that the sediment-trap efficiency of the vegetated wetlands on lower Magela is high at ~89.5%.
Sea-level rise associated with global warming will increase across Kakadu causing widespread saltwater intrusion. We aimed to understand how soil bacteria might respond to these impacts, by sampling transects in different river zones. We found diverse bacterial communities that were sensitive to soil variables, suggesting that saltwater intrusion may affect bacterial contributions to the dynamic floodplain ecosystems of Kakadu.
MF16118Seasonal habitats, decadal trends in abundance and cultural values of magpie geese (Anseranus semipalmata) on coastal floodplains in the Kakadu Region, northern Australia
The magpie goose is an iconic tropical species highly valued as a conservation asset and by Aboriginal people as a cultural resource. Their spatial and temporal dynamics in the Kakadu Region of Northern Australia are characterised at seasonal and decadal time scales using long-term aerial survey data. The customary harvesting practices of geese and their eggs in the region show that their cultural value extends beyond consumption of bush-food.
MF16175Vulnerability of fish and macroinvertebrates to key threats in streams of the Kakadu region, northern Australia: assemblage dynamics, existing assessments and knowledge needs
Key stream fauna in Kakadu National Park face severe threats in 100+ years associated with climate change, invasive species, and mine-site rehabilitation. Sea level rise will salt the coastal floodplains and the fauna must then rely on reduced upstream refuges vulnerable to strong swings between more intense El Niños and La Niñas. Rates and extremes of future climate change appear unprecedented, making predictions associated with past climate change unreliable.
MF16148Dynamics of plant communities and the impact of saltwater intrusion on the floodplains of Kakadu National Park
On the Kakadu floodplains, the distribution of different plant communities varies yearly, related to flooding duration and water depth. Because these floodplains are close to the coast, they are vulnerable to saltwater intrusion as the sea levels rise. The most obvious effect of this will be the transformation from freshwater vegetation to salt-tolerant plants in susceptible areas.
MF17334Ichthyofaunal assemblages in shallow littoral habitats of permanently open estuaries and intermittently closed and open lakes or lagoons in Otago, New Zealand
This study compares fish assemblages of permanently open estuaries and intermittently closed and open lakes or lagoons (ICOLLs) in Otago, New Zealand. The results indicated that estuary–ocean connection and season play a key role in structuring fish assemblage structure of estuaries.
Recent years have seen considerable research effort devoted to understanding Australian marine climate-change impacts and adaptation. Literature analysis indicated that a structured, national-level program underpinned by strong stakeholder engagement is beneficial for rapidly addressing key climate-change questions and adaptation needs across fisheries, aquaculture, conservation and tourism sectors. Additional effort is still needed with regard to adaptation research.
MF17278Identification of two hatch date-dependent cohorts and variation in early growth rate of mud carp (Cirrhinus molitorella) in the Pearl River Delta, China
In this study, we observed the seasonal recruitment patterns, analysed temporal variations in early growth rates using daily increments in the otolith and assessed the effects of environmental variables on the growth rate of juvenile mud carp (Cirrhinus molitorella), one of the most important commercial fish species in the Pearl River, in China.
MF17256Defining the importance of ecological processes for monitoring aquatic habitats for conservation and rehabilitation objectives at the Ranger uranium mine, Kakadu Region, Australia
Consideration of ecological processes is required to ensure the success of ecological restoration and conservation activities. An assessment was conducted to ensure that current and future environmental monitoring programs are in place to safeguard the protection of aquatic ecological processes, particularly in the context of rehabilitation of Ranger uranium mine.
MF17064Effects of herbivores, wave exposure and depth on benthic coral communities of the Easter Island ecoregion
Herbivorous fish biomass, sea urchin (Diadema savignyi) density, and algal and coral cover at 10 and 20 m was studied in the Easter Island ecoregion to identify patterns and relationships among these groups and the potential roles of herbivores, wave-energy exposure, and depth on these communities. Differences were found between islands and among levels of wave exposure. These patterns and the concordant patterns between herbivores and algae suggest herbivores and wave energy likely play important roles in structuring these benthic communities.
MF17327Use of otolith shape to inform stock structure in Patagonian toothfish (Dissostichus eleginoides) in the south-western Atlantic
We showed how variability in otolith shape can be used to reflect isolation and connectivity within and among stocks of Patagonian toothfish across the Patagonian Shelf, and South Georgia and the South Sandwich Islands (SGSSI). Differences in otolith shape indicated clear differentiation between, as well as within, these two regional groupings. The results suggest that despite some degree of connectivity, large-scale mixing of adult toothfish across the Patagonian Shelf and SGSSI is limited.
MF17357Seed germination of tangled lignum (Duma florulenta) and nitre goosefoot (Chenopodium nitrariaceum) under experimental hydrological regimes
This study investigated relationships between hydrological regime and the germination and buoyancy of tangled lignum and nitre goosefoot seeds. Tangled lignum germinated best on soaked soil and soil inundated for 20 days. Nitre goosefoot germinated best on soil inundated for 5 days and soaked soil. Seeds of tangled lignum floated for longer than seeds of nitre goosefoot (≥7 v. ≤7 days respectively).
Wrack is common in surf zones of sandy beaches, yet few studies have investigated food webs in those environments. From samples of wrack and fauna in South Australian surf zones, we established baseline food webs based on stable isotopes and fish gut contents. Fish feed among wrack, but also forage elsewhere, and macroinvertebrates do use wrack as a food source.
MF17009Assessment of water quality from the Normanby River catchment to coastal flood plumes on the northern Great Barrier Reef, Australia
Water quality conditions were measured in a semi-pristine catchment in the Far Northern Great Barrier Reef (GBR). Changes in water quality from upper catchment tributaries to GBR marine waters are assessed over three flood events. Data collected along the salinity gradient in this large northern catchment are compared to the more developed southern catchments.
MF17192Embryos of eastern rainbowfish Melanotaenia splendida splendida (Peters, 1866) tolerate fluctuating hypoxia
Low dissolved oxygen concentrations (hypoxia) can profoundly affect larval development in fish, but the effects of hypoxia on freshwater fish from tropical Australia are not well understood. In this study, the effects of daily fluctuations in hypoxia were investigated for embryos of a species that is common in wetlands of tropical Queensland. Eastern rainbowfish embryos appear to be tolerant to fluctuating hypoxia, possibly because eggs are laid predominantly on submerged plants.
Nest-building by fishes and its ecological role in reef ecosystems are poorly documented. We described the nest and nest-building behaviour of the endangered Brazilian basslet (Gramma brasiliensis). Males build complex bird-like nests using macroalgae thalli that camouflage nest entrance and form a cushion bed for egg laying. Nesting seems to be a critical aspect of the reproductive strategy of this species.
MF17237Making management decisions in the face of uncertainty: a case study using the Burdekin catchment in the Great Barrier Reef
In this study, we provide a methodology for quantifying and communicating uncertainty associated with water quality predictions. We show how exceedance probabilities can identify hot spots for future monitoring or remediation activities, and how these can be used to inform water quality target-setting activities. The approach is tested in the Upper Burdekin catchment, which drains to the Great Barrier Reef.
MF17043An integrated risk-assessment framework for multiple threats to floodplain values in the Kakadu Region, Australia, under a changing climate
The floodplains of the Kakadu Region, world-renowned for their natural and cultural values, are threatened by invasive species and future sea-level rise. A risk assessment that integrates both threats to multiple values out to 2100 was undertaken, and suggested that floodplains will likely transform to marine-dominated ecosystems that cannot be managed back to previous conditions. The study highlighted the importance of freshwater refugia because both their value and vulnerability will increase over time.
MF17210Horseshoe crabs as potential sentinel species for coastal health: juvenile haemolymph quality and relationship to habitat conditions
The present study investigated the use of non-lethal sampling of blood from horseshoe crabs to indicate the general status of coastal habitats. Changes in blood composition pattern of two Asian juvenile horseshoe crab species were found to be sensitive to reflect heavy metal and nutrient concentrations of intertidal sediments. Such a non-lethal sampling protocol can be useful for routine monitoring purposes.
MF17125Biological aspects of the associations of biting midges (Diptera: Ceratopogonidae) in two saline rivers of the Elton Lake Basin, Russia
We studied species composition, density, biomass and production of biting midges in two saline rivers (Volgograd region, Russia). They are a substantial seasonal food source for birds in this arid region. Average monthly production of biting midges during the study period in the saline rivers was much higher than annual production in some fresh rivers and lakes of world. For the first time, feeding spectra of one of the species of biting midges was studied using fatty acid analyses.
This study has shown a new technique to control asterinid grazers in field experiments. The efficiency of alternative methods (sticky barrier and antifouling paint) for field manipulations of the cushion star, Parvulastra exigua, was tested. The authors found that antifouling paint can retain starfish within plots delimited by the paint, whereas sticky barriers will be crossed by the starfish.
MF17209How does marker choice affect your diet analysis: comparing genetic markers and digestion levels for diet metabarcoding of tropical-reef piscivores
Tropical reefs are highly diverse ecosystems, and reliable biomonitoring, through genetic diet analysis (i.e. metabarcoding), is crucial to understand future interactions in the face of climate change. The metabarcoding success of different molecular marker genes has rarely been assessed in such ecosystems. This novel study showed that marker success for prey identification is highly dependent on the reference database, taxonomic scope, DNA quality, amplicon length and sequencing platform.
MF17252Mangrove response to sea level rise: palaeoecological insights from macrotidal systems in northern Australia
This paper explores coastal wetland response to sea-level rise. It reviews changing mangrove distribution over past millennia determined from cores in macrotidal estuaries of northern Australia. Mangroves retreated on the open coast, but were able to keep pace with gradual sea-level rise in adjacent estuaries. These insights imply that mangrove adjustment in future will vary as a function of local topography and sediment availability.
MF17241Deficiencies in our understanding of the hydro-ecology of several native Australian fish: a rapid evidence synthesis
Knowledge of how Australian native fish respond to changes in river flows is essential to inform the restoration of these flows. However, most recommendations are based on expert knowledge. We used systematic methods to review the literature on several Australian fish species, but found very little relevant evidence. This demonstrates the need for targeted monitoring and research to fill these important knowledge gaps.
MF17247A sponge of the Cliona viridis complex invades and excavates corals of the Gulf of Mannar, south-eastern India
We observed a dominant brown clionaid bioeroding sponge on south-eastern Indian coral reefs in 5-m water depth. Of all corals present and despite recent coral mortality, the encrusting Cliona sp. infested only live foliose Turbinaria mesenterina, of which ~50% colonies were affected. This infestation frequency is regarded as high, and the sponge should be fully taxonomically identified and monitored in the future.
MF17092Inter-population variability in growth and reproduction of invasive bleak Alburnus alburnus (Linnaeus, 1758) across the Iberian Peninsula
An invasive, non-native fish in the Iberian Peninsula, the common bleak threatens Iberia’s valuable endemic freshwater fauna. Wide inter-population variability in growth and reproduction was found across the main Iberian rivers and a ‘reference’ native population from France. These results may aid to mitigate impacts exerted by this bio-invasion on the endangered fish communities of Mediterranean Europe.
MF17250More (or less?) bounce for the ounce: a comparison of environmental DNA and classical approaches for bioassessment
Environmental (e)DNA is increasingly being used for biological assessment of aquatic ecosystems and although it is often touted as being more powerful, yet cheaper, than classical approaches to biomonitoring, empirical evidence is scarce. Herein we use a case study to contrast and compare classical and eDNA methods in terms of information generated balanced with costs and expertise.
MF17218Population genetics of Pampus echinogaster along the Pacific coastline of China: insights from the mitochondrial DNA control region and microsatellite molecular markers
Genetic diversity and structure of Pampus echinogaster were analysed using mitochondrial and nuclear DNA markers. High genetic homogeneity was found among Chinese populations of this species. The complex migratory ability and high dispersal of ichthyoplankton, as well as China’s offshore circulation, may play major roles in shaping the existing genetic structure of P. echinogaster.
Mangroves in Kakadu National Park in Australia’s Northern Territory have undergone significant changes, occupying much of the lowlands c. 6000 years ago, but are now confined to the river margins and islands. Recent observations from satellite and aircraft have indicated that fluctuations in sea level exert a significant effect on the distribution of mangroves, with a drop in the sea level from 2015 to 2016 contributing to unprecedented dieback on the landward margins.
MF17262Interactive effects of hypoxia and dissolved nutrients on the physiology and biochemistry of the freshwater crayfish Paranephrops zealandicus
Low dissolved oxygen (hypoxia) in fresh waters is often a consequence of elevated dissolved nutrients, but only rarely are combined effects of nutrients and hypoxia on biota considered. In the at-risk freshwater crayfish Paranephrops zealandicus, hypoxia had several negative effects on respiratory and cardiac physiology and tissue biochemistry, but there was little additional effect of high ammonia or nitrite.
MF16166Understanding climate-change adaptation on Kakadu National Park, using a combined diagnostic and modelling framework: a case study at Yellow Water wetland
We have developed an approach to assess sea-level rise effects on socio-ecological systems, using Yellow Water wetland on Kakadu National Park as a case study. Sea-level rise will cause profound changes in the Park, but it may also provide an opportunity to bring together Indigenous and non-Indigenous knowledge towards a commonly perceived threat. Strategies that facilitate Indigenous people’s participation in research and monitoring programs are needed to improve understanding of impacts and enhance adaptive capacity.
We examined the effects of beaver impoundments on spatial and temporal variation in fish species composition and size structure. We placed our results in the context of the metacommunity theory. Although local communities changed over time, the main metacommunity characteristics remained constant. Fish must follow environmental changes for their populations and communities to persist in streams inhabited by beavers.
MF17082Spatially dynamic maternal control of migratory fish recruitment pulses triggered by shifting seasonal cues
Environmental regimes set the timing and location of early life history events of migratory species with synchronised reproduction. This study assessed how the environment and spawners modulate recruitment variability and persistence of the Missouri River shovelnose sturgeon (Scaphirhynchus platorynchus) under modified seasonal habitat conditions. Model simulations illustrate that environmentally amplified maternal control of early life histories can lower sturgeon population stability and resilience under perturbations.
MF17145Nutritional vulnerability in zoeal stages of the yellowline arrow crab Stenorhynchus seticornis (Brachyura: Majoidea)
This study investigated the nutritional vulnerability of the larval stages of yellowline arrow crab (Stenorhynchus seticornis) to evaluate the physiological state of the larvae in their natural environment. Larvae were assigned to two experiments: (1) with increasing days of starvation and subsequent days of feeding; and (2) with increasing days of feeding and subsequent days of starvation.