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Metacommunity ecology provides a basis for understanding how ecological communities are assembled. Metacommunity theory can be applied to assess the effects of anthropogenic disturbance on freshwater communities. However, few studies have examined how species-specific responses to environmental covariates can generate broader patterns in freshwater metacommunities. I determined occupancy patterns in an amphibian metacommunity to identify important predictors of reproduction at wetland sites. I conducted surveys at 49 wetlands for tadpoles with fish traps and dip netting in an urbanising region in southeastern Australia. The larvae of seven frog species were detected. There were negative relationships between the probabilities of reproduction at a site and the relative abundance of the eastern mosquitofish (Gambusia holbrooki) and wetland electrical conductivity. There was a positive relationship between tadpole occupancy and the proportion of accessible habitat within 1000 m of a site, a measure of the combined effects of roads and habitat amount. These results highlight the negative effect of predatory Gambusia on frog communities and illustrate the importance of the species-sorting and mass-effect perspectives of metacommunity theory at multiple spatial scales. Habitat restoration projects for amphibians should remove exotic fish or prevent their establishment in managed wetlands and maintain habitat connectivity to facilitate dispersal. [ABSTRACT FROM AUTHOR]

The platypus is a semi-aquatic mammal, endemic to freshwater habitats of eastern Australia. There are gaps in the understanding of platypus movement behaviour within river systems, including spatial and temporal organization of individuals. We tracked movements of 12 platypuses on the regulated Snowy and Mitta Mitta Rivers for up to 12-months, the longest continuous tracking of platypus using acoustic telemetry. Platypuses remained relatively localized, occupying 0.73–8.45 km of river over 12 months, consistent with previous tracking studies over shorter periods. Males moved further than females, and larger males had higher cumulative movements, suggesting a possible relationship to metabolic requirements. Platypuses moved greater distances on the Mitta Mitta River, possibly associated with impacts of altered flow regimes to their macroinvertebrate diet. Increased movements and diurnal activity during winter were primarily driven by males, possibly attributable to breeding behaviours, rather than increased costs of winter foraging. Evidence for relatively small movements has implications for declining populations, given areas of localised declines are unlikely to be supplemented by migrating platypuses, especially when dispersal is restricted by dam walls. Understanding platypus movement behaviour is pertinent for their conservation, as water resource development and habitat modification continue to reduce connectivity between populations across their distribution. [ABSTRACT FROM AUTHOR]

This account presents information on all aspects of the biology of Crassula helmsii (Kirk) Cockayne (New Zealand Pygmyweed, Australian Swamp Stonecrop) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation.Crassula helmsii is an invasive aquatic macrophyte originating from Australia and New Zealand. The first naturalized population was recorded in Britain in 1956. All British specimens appear to represent a single lineage. DNA analysis indicates that British specimens originate from Australia.Crassula helmsii is capable of growing in a wide range of lentic freshwater and riparian habitats. It may grow as free floating, submerged, emergent or terrestrial forms. Morphology can differ markedly on the same stem.Flowers are produced, but with no known pollinators outside of its native range. Reproduction is thought to be predominantly by asexual methods outside Australia and New Zealand, through stem fragmentation and dispersal. Seed germination outside the native range appears to be very rare and poorly understood.Crassula helmsii has been and still is controlled by active management because of fears that its capacity to produce monocultures will lead to loss of biodiversity in the plant communities it invades. Evidence for species losses due to colonization by C. helmsii is rather anecdotal, although suppression of native biomass through competition has been reported. No consistently effective control procedures have been identified. [ABSTRACT FROM AUTHOR]

Coquillettidia linealis (Skuse, 1889) is a common mosquito species, widespread in south‐east Australia. It is associated with permanent freshwater habitats where it can be very abundant and the cause of significant nuisance biting. Additionally, Cq. linealis is thought to be a significant vector of some arboviruses, such as Ross River virus, because numerous isolates have been recovered from the species. Although recognition of the species in 1889 was based on adult females, the larval stage has never been described. This lack of description has been primarily because the larvae are cryptic; all larval stages have modified respiratory siphons that pierce and remain attached to subsurface tissues of aquatic plants, from which they gain oxygen. Similarly, pupae have modified respiratory trumpets to attach to plants below the water surface. In this study, adult host‐seeking females were field collected and blood fed for oviposition, and the resulting larvae were reared to adults to establish a sustainable colony, from which fourth‐instar larvae were selected to provide the first formal description of this life stage of Cq. linealis. This description allows differentiation of Cq. linealis from larvae of its local congener Coquillettidia xanthogaster (Edwards) as well as local Mansonia species but not the larvae of the other Coquillettidia species in Australia that are still undescribed. [ABSTRACT FROM AUTHOR]

Australia experienced its largest recorded outbreak of Ross River virus (RRV) during the 2014-15 reporting year, comprising >10,000 reported cases. We investigated epidemiologic, entomologic, and virologic factors that potentially contributed to the scale of the outbreak in Queensland, the state with the highest number of notifications (6,371). Spatial analysis of human cases showed that notifications were geographically widespread. In Brisbane, human case notifications and virus detections in mosquitoes occurred across inland and coastal locations. Viral sequence data demonstrated 2 RRV lineages (northeastern genotypes I and II) were circulating, and a new strain containing 3 unique amino acid changes in the envelope 2 protein was identified. Longitudinal mosquito collections demonstrated unusually high relative abundance of Culex annulirostris and Aedes procax mosquitoes, attributable to extensive freshwater larval habitats caused by early and persistent rainfall during the reporting year. Increased prevalence of these mosquitoes probably contributed to the scale of this outbreak. [ABSTRACT FROM AUTHOR]

Biomonitoring microplastics in freshwater ecosystems has been insufficient in comparison with its practice in marine environments. It is an important first step to understand microplastic uptake in organisms when assessing risk in natural freshwater habitats. We conducted microplastic biomonitoring within the Greater Melbourne Area; where the microplastic baseline pollution in freshwater organisms was largely unknown. A common noxious fish species, Gambusia holbrooki , was targeted. Individuals (n = 180) from nine wetlands were analyzed. Uptake pathway, size, weight and gender were examined in relation to microplastic uptake in the body (presumed uptake via gut) and head (presumed uptake via gills). On average, 19.4% of fish had microplastics present in their bodies with an abundance of 0.6 items per individual (items/ind) and 7.2% of fish had microplastics in their heads with an abundance of 0.1 items/ind. Polyester was the dominant plastic type and fibers were the most common shape. The amount of microplastics in Gambusia holbrooki in current study is relatively low in a global comparison. The bodies of fish contained more microplastics on average than heads, and the size of microplastics detected in heads were smaller than those found in bodies. Microplastic uptake was directly proportional to size and weight. Furthermore, female individuals showed a tendency to ingest more microplastics than males. Laboratory experiments under controlled conditions are suggested to further explore such relationships. Our findings are important to understanding the potential ecological risks posed by microplastics to organisms in freshwater environments and provide suitable methodologies to conduct biomonitoring in future investigations. Image 1 • Microplastics were detected in the body and head of Gambusia holbrooki from Australia. • The bodies of fish contained more microplastics than the heads. • Microplastics detected in heads were smaller than those found in the bodies. • Microplastic uptake was directly proportional to fish size and weight. • Female individuals showed a tendency to ingest more microplastics than males. Capsule abstract : Microplastic uptake in Gambusia holbrooki via different pathways depended on fish size, weight and gender. [ABSTRACT FROM AUTHOR]

Summary: Cylindrospermopsis (Raphidiopsis) raciborskii is an invasive, filamentous, nitrogen‐fixing cyanobacterium that forms frequent blooms in freshwater habitats. While viruses play key roles in regulating the abundance, production and diversity of their hosts in aquatic ecosystems, the role(s) of viruses in the ecology of C. raciborskii is almost unexplored. Progress in this field has been hindered by the absence of a characterized virus–host system in C. raciborskii. To bridge this gap, we sequenced the genome of CrV‐01T, a previously isolated cyanosiphovirus, and its host, C. raciborskii strain Cr2010. Analyses suggest that CrV‐01T represents a distinct clade of siphoviruses infecting, and perhaps lysogenizing, filamentous cyanobacteria. Its genome contains unique features that include an intact CRISPR array and a 12 kb inverted duplication. Evidence suggests CrV‐01T recently gained the ability to infect Cr2010 and recently lost the ability to form lysogens. The cyanobacterial host contains a CRISPR‐Cas system with CRISPR spacers matching protospacers within the inverted duplication of the CrV‐01T genome. Examination of metagenomes demonstrates that viruses with high genetic identity to CrV‐01T, but lacking the inverted duplication, are present in C. raciborskii blooms in Australia. The unique genomic features of the CrV/Cr2010 system offers opportunities to investigate in more detail virus–host interactions in an ecologically important bloom‐forming cyanobacterium. [ABSTRACT FROM AUTHOR]

Recent anthropogenic influences on freshwater habitats are forcing anuran populations to rapidly adapt to high magnitude changes in environmental conditions or face local extinction. We examined the effects of ecologically relevant elevated salinity levels on larval growth, metamorphosis and survival of three species of Australian anuran; the spotted marsh frog (Limnodynastes tasmaniensis), the painted burrowing frog (Neobatrachus sudelli) and the green and golden bell frog (Litoria aurea), in order to better understand the responses of these animals to environmental change. Elevated salinity (16% seawater) negatively impacted on the survival of L. tasmaniensis (35% survival) and N sudelli (0% survival), while reduced salinity had a negative impact on L. aurea. (16% seawater: 85% survival; 0.4% seawater: 35% survival). L. aurea tadpoles survived in salinities much higher than previously reported for this species, indicating the potential for inter-populations differences in salinity tolerance. In L. tasmaniensis and L. aurea, development to metamorphosis was fastest in low and high salinity treatments suggesting it is advantageous for tadpoles to invest energy in development in both highly favourable and developmentally challenging environments. We propose that this response might either maximise potential lifetime fecundity when tadpoles experience favourable environments, or, facilitate a more rapid escape from pond environments where there is a reduced probability of survival. [ABSTRACT FROM AUTHOR]

The article introduces the first pre-Pliocene record of darter (Anhingidae) in Australia. A sole darter relic was located at the Snake Dam locality in South Australia. It states that darters, also recognized as "snakebirds," are expert diving piscivores which survive in tropically freshwater habitats. The discovery of this anhingdae reveals the likelihood of Early Oligocene to Eocene age for the common lineages of anhingids and phalacrocoracids.

Abstract: The genus Craterocephalus is one of the 11 genera within the family Atherinidae. It is the only genus in the family that has undergone an extensive radiation within freshwater habitats. Five species groups are represented within the genus, with 18 species found in Australia, six in New Guinea and one in East Timor. Craterocephalus is the equal fourth most widespread genus in Australian freshwater environments (occurring in 21 out of 31 biogeographic regions), and the most speciose (13 species). This allows identification of broad biogeographic patterns that can later be contrasted with other groups that overlap geographically. Phylogenetic relationships of Craterocephalus were examined using the cytochrome b gene. Results confirmed the monophyly of five species groups, with the marine “new honoriae” group being basal, suggesting a single invasion of freshwater habitats. The “capreoli” group and one species, C. munroi represents reversals back into marine/estuarine conditions. The most striking result from this study is the degree of differentiation between species in the separate freshwater groups within Craterocephalus. Despite often occurring sympatrically in river systems, interspecies and population divergences from “eyresii” and “stramineus” groups were substantially larger than divergences within “stercusmuscarum.” Despite being one of the best freshwater groups characterized morphologically within Australia, it is clear that additional morphological work is required to clarify taxonomic problems within Craterocephalus, as molecular data suggest some species are synonymous, while others appear to represent multiple unrecognized taxa. [Copyright &y& Elsevier]

Many rigorous methods have been developed to manipulate and sample rocky benthic species, but development of field methodology is less advanced for disturbance-prone rocky habitats e.g. cobbles and boulders. These habitats can have ecological and economic importance but research is complicated by their complex physical structure that necessitates causing disturbance when sampling, possibly resulting in mobile species being lost from samples. We used simulated/controlled sampling conditions to determine the proportions of mobile species successfully captured or lost during sampling. Boulders and cobbles were lifted out of shallow water (i.e. "littoral" sampling) and sampled in simulated sublittoral conditions, targeting biota attached to the undersurfaces. Variation in sample losses associated with different methods was tested – sampling in shallow vs deep water and small vs large boulders/cobbles. Different species and locations were also compared. Tests were done to determine contexts producing minimal losses and thus deserving prioritisation. Experiments were replicated in southern Australia and NE Baltic Sea. Large proportions of littoral amphipods and isopods were not successfully captured during sampling in most contexts (overall mean loss = 35%). This means lifting boulders from shallow water cannot accurately sample them. This finding is important especially for highly researched boulder or cobble associated invasive amphipods with large ecological impacts. Seventeen percent of littoral gastropods were lost from samples in both regions; in Australia greater proportions were occasionally lost when sampling larger boulders. Chitons and one gastropod (Theodoxus fluviatilis) could be sampled from shallow water with consistently high reliability. During sublittoral sampling, mean sample loss was 13% with no significant interspecific variability. Boulder/cobble size and water depth rarely caused influence. The results reveal sampling contexts where more sophisticated methods may be used for highly accurate abundance measurements in recent research programmes of ecological restoration and conservation of rare species involving marine but also freshwater habitats. Unlabelled Image • Coastal boulder and cobble reefs often have ecological and economic importance • Littoral sampling disturbance caused loss of many peracarids but fewer molluscs • For sublittoral sampling 13% of samples were lost with no interspecific variability • Water depth and boulder/cobble size rarely caused influence on sample loss rates • The results inform sampling methodology for marine conservation and restoration [ABSTRACT FROM AUTHOR]

• Floodplain productivity and inundation assessed using remote sensing indicators. • River discharge is a stronger indicator of hot spots of biomass accumulation. • Floodplain inundation and primary production are driven by flow and local rainfall. • Upstream catchment contributes to the connectivity and productivity of floodplain. • Fluctuations in climate will be key constraints on freshwater habitats. The ecological communities supported by freshwater habitats and wetlands that persist from floodplain inundation generate numerous cultural, recreational and economic values via commercial fisheries and other human uses of these habitats. However, the alteration of flow connectivity, degradation, and disruption of physical processes that sustain different levels of organisms (e.g., primary producers) are threats that affect aquatic biodiversity and the productivity of these habitats. Therefore, the large scale assessment of freshwater habitats for proactive water resources planning and the development of climate change mitigation and resource management strategies is essential. However, such monitoring and assessment is complicated by the inaccessibility of many large wetland systems during times of inundation, making in situ sampling unfeasible at a time when high levels of aquatic primary producers are generating food and energy sources for higher order consumers. To understand the physical dynamics of aquatic primary producers and freshwater habitats (1991–2019) during such times in a large floodplain river in northern Australia (Gilbert catchment), this study integrated Landsat-derived modified normalised difference water index and normalised difference vegetation index in a classification tree model. Thereafter, key hydrological drivers (rainfall and river discharge) of floodplain productivity and connectivity were assessed using a range of multivariate techniques. Results show that the floodplain had a high aquatic plant biomass during the summer wet season based on the correlation between aquatic biomass accumulation (hot spots) and inundation (r = 0.83 @ phase lag < 1 month) during such period. River discharge (r = 0.68 @ lag = 1 month) at downstream Gilbert catchment appear to be a relatively stronger indicator of hot spots of floodplain biomass accumulation as opposed to local rainfall (r = 0.57 @ lag = 3 months). While the downstream discharge explains a significant proportion of variability in the leading orthogonal mode of rainfall (r = 0.83), statistical relationships developed between discharge/rainfall and the distribution of aquatic primary producers confirm that both rivers (flow) and local rainfall are key optimal predictors of inundation and sites of primary producers with river flows being a better indicator of the latter. It is therefore argued that hydro-meteorological fluctuations will be key constraints on freshwater habitats and the growth of primary producers, albeit, human disturbance of flow can impact on floodplain productivity. As illustrated in this study, such constraints are reflected in the spatial patterns and changing characteristics (connectivity and spatial heterogeneity) of hot spots of primary producers and freshwater habitats (Palustrine, Lacustrine, and Riverine ecosystems). [ABSTRACT FROM AUTHOR]

• Cell concentration increased more with temperature than pCO2 in continuous cultures. • Species and strains differed in growth response to increased temperature and pCO2. • Straight R. raciborskii strains have five more carbon acquisition genes than coiled. • Straight strain cell concentration increased more with higher pCO2 than coiled strain. Global increases in atmospheric CO 2 and temperatures will impact aquatic systems, with freshwater habitats being affected. Some studies suggest that these conditions will promote cyanobacterial dominance. There is a need for a clearer picture of how algal species and strains within species will respond to higher temperatures and CO 2 , especially in combination. This study examined two chlorophytes (Monoraphidium and Staurastrum), and two strains of the cyanobacterium Raphidiopsis raciborskii (straight S07 and coiled C03), to determine how the combination of higher temperature and CO 2 levels will affect their growth and maximum cell concentrations. Continuous cultures were used to compare the steady state cell concentrations at 28 °C and 30 °C, and CO 2 partial pressures (pCO 2), 400 and 750 ppm for all cultures, and in addition 1000 ppm at 28 °C for R. raciborskii strains. This study showed that, for all species, water temperature had a greater effect than higher pCO 2 on cell concentrations. There were clear differences in response between the chlorophyte species, with Monoraphidium preferring 28 °C and Staurastrum preferring 30 °C. There were also differences in response of the R. raciborskii strains to increasing temperature and pCO 2 , with S07 having a greater increase in cell concentration. Genome analysis of R. raciborskii showed that the straight strain has five additional carbon acquisition genes (β-CA , chpY , cmpB , cmpD and NdhD4), indicative of increased carbon metabolism. These differences in the strains' response to elevated pCO 2 will lead to changes in the species population structure and distribution in the water column. This study shows that it is important to examine the effects of both pCO 2 and temperature, and to consider strain variation, to understand how species composition of natural systems may change under future climate conditions. [ABSTRACT FROM AUTHOR]