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The improvement of techniques and analyses to understand the movement of freshwater turtles has helped managers in decision-making and the establishment of management strategies for these animals, which suffer numerous threats. We analyzed the available scientific literature on the use of telemetry in the study of the movement ecology of freshwater turtles, seeking to assess the most commonly used approaches. To this end, we carried out a systematic review of articles published until December 2022 using the PRISMA protocol. We found 104 articles published between 1980 and 2022, with a clear increase in the number of publications in later years. We found publications in 40 journals with 295 authors, 150 institutions and 261 keywords. Three countries had major contributions, and we found studies with 50 species, the most recurrent being Emydoidea blandingii and Glyptemys insculpta. The most commonly used technique to study turtle movement was radiotelemetry. The use of Minimum Convex Polygon – MCP and Kernel Density Estimation – KDE was present in 56% of the studies in the last 10 years, and the evaluation of the home range of the species was the most recurrent type of study. The studies covered 33 freshwater ecoregions, and although most studies were carried out in anthropized areas, covering only 16.2% of all endangered freshwater turtle species and 11.4% of all threatened by international trade, the conservation approach has been increasingly recurrent. Our results highlight trends and gaps in the study of the ecology of freshwater turtle movements and highlight the importance of telemetry as an essential tool for species conservation. Highlights: This study reviews 104 articles on telemetry in aquatic turtles, highlighting the predominant use of radiotelemetry. It reveals a focus on anthropized areas and significant gaps, with only 16.2% of endangered species studied. The research underlines the importance of telemetry in turtle ecology conservation. Conservation efforts are growing, despite existing gaps." [ABSTRACT FROM AUTHOR]

Freshwater biodiversity faces a critical situation globally. Current efforts to protect and conserve India's freshwater biodiversity have been insufficient in light of emerging challenges. To address this, we propose 14 science-based and policy-backed recommendations aimed at achieving long-term protection of Indian freshwater ecosystems and biodiversity conservation goals. Managers of India's nodal agencies have expressed support for implementing these recommendations. The Wildlife Institute of India has recently launched a pioneering master's degree programme in freshwater ecology and instituted scholarships for local citizens known as 'Guardians of the Ganga', who are actively engaged in conserving biodiversity along the Ganga River under the auspices of the 'Biodiversity Conservation and Ganga Rejuvenation' project sponsored by the National Mission for Clean Ganga. These initiatives align closely with our proposed recommendations. Implementing these timely recommendations by policymakers is crucial to safeguarding India's freshwater biodiversity. [ABSTRACT FROM AUTHOR]

'Biodiversity offsetting' aims to address the residual negative environmental impacts of human development. It's goal is to achieve No Net Loss (NNL), and preferably a Net Gain of biodiversity attributes between development and offset sites. Biodiversity offsetting suffers from a lack of 'proof of concept', as little work has been done to critically test the ecological efficacy of offsetting practices. Offsetting of stream ecological functions was investigated in Aotearoa New Zealand, via review of regulatory documentation for 76 offsets and field assessments of 14 offset sites. Field results indicated some functions, including fish passage connectivity, respond rapidly post-offset enhancement whilst others exhibit recovery lags (such as fish spawning habitat provision). However, most offsets were considered unlikely to achieve NNL due to failures in practice and process. Factors included inadequate consideration for restoration uncertainty, inappropriate monitoring conditions, insufficient data and inequivalent trade-offs. Key linkages between aquatic and terrestrial ecosystems, particularly regarding floodplain connectivity, were poorly considered in offset implementation. Thus, development may be occurring based on inadequate regulatory processes, and poorly evaluated ecological outcomes. These findings join a growing body of evidence which indicates that, in the context of a global biodiversity crisis, offsetting is not achieving its purpose of NNL. [ABSTRACT FROM AUTHOR]

Freshwater mussels are both critically important in their ecosystems and rapidly declining around the world. Damming is a key reason for this decline in many locations because it affects the flow and turbidity of river systems, leading to numerous detrimental effects on benthic communities. Although the ecological effects of impoundment have been well studied on timescales ranging from years to decades, the ecological effects of impoundment on longer (50–100 years) timescales are less well understood, with a key question being: how long after the building of dams and impoundments do we expect community structure to continue changing? In this study, we explore historical changes in the freshwater mussel assemblages in Kentucky Lake (dammed in 1944) using decades-long collections housed at Murray State University in combination with other historical records. After digitizing these collections and applying a robust rarefaction protocol to account for uneven sampling, we quantify changes in unionid assemblage structure alongside coeval water quality data collected through the Kentucky Lake Long-Term Monitoring Program. We find that subsampled richness exhibited declines after dam construction with losses among opportunistic taxa, channelization-tolerant taxa, and impoundment-intolerant taxa. We also find increases in the proportions of equilibrium taxa throughout the dataset. Overall, the assemblage composition reached an equilibrium by the year 2000 (50 years after impoundment). In concert, river water quality data show a decline in turbidity and increase in light penetration in the period 1988–2020. Although the geohistorical records treated in this study are patchy in time, we argue that they are nonetheless valuable and illustrate that freshwater ecosystems may serve as potential sites of restoration decades after anthropogenic disturbance. In turn, this emphasizes the importance of geohistorical collections to studying long-term changes in community structure and developing strategies for conservation and environmental remediation. [ABSTRACT FROM AUTHOR]

This article focuses on defining hydromorphological features to be extracted from historical maps by means of digital map processing techniques. The hydromorphological features, evolving through time, can be described quantitatively by the development and application of various ecological metrics to study the spatiotemporal change of the natural and built freshwater environment. With the goal to support future revitalization efforts, this article first reviews the theory on quantifying spatiotemporal change using landscape and ecological metrics, ranging from simple shape metrics (e.g., shoreline length) to more complex hydromorphological indexes (e.g., river braiding index). Second, the hydromorphological features themselves are important to consider in terms of data quality and uncertainty as they might inherit errors due to the low-quality maps, the extraction process, or due to poor definitions used during feature extraction efforts. Errors introduced by poorly defined features can be avoided by the use of a well-structured definition system. Thus, the article concludes in a new concept categorizing hydromorphological features and the changes they can undergo. The definition framework integrates novel perspectives for defining and evaluating features from the Siegfried and old Swiss national map, including key aspects from the theory. [ABSTRACT FROM AUTHOR]

The present paper describes two new Chinese species of maricolan planarians through an integrated approach, including morphological, histological and molecular phylogenetic analyses. One new species forms the third species of the genus Pacifides and represents the first record of this genus from the Western Pacific. Further we document a third, new species of the genus Paucumara that is fully restricted to freshwater habitats, as it occurs on the shores of the Jialing River in Chongqing municipality far into the interior of China. Molecular phylogenetic analyses enabled us to determine, for the first time, the position of the genus Pacifides in the phylogenetic tree of the marine triclads. We also provide information on the feeding and reproduction of the new species of Pacifides. The paper concludes with two speculative scenarios on the evolutionary history that may have led to the present-day far inland occurrence and freshwater ecology of the new species of Paucumara; one scenario involves tectonic uplift-driven speciation and niche evolution, while the other invokes passive upstream dispersal via the Yangtze River. [ABSTRACT FROM AUTHOR]

Freshwater resources are under stress because of anthropogenic activities and the demand for water increasing on a global scale, including hydropower. There are presently plans to expand the use of hydropower within eastern and southern Africa. A key river system identified as a potential source of energy is the Pungwe River, with the proposed Pavua Dam located within the middle reaches of the system in Mozambique. However, impoundments have been recorded to negatively influence ichthyofauna communities via alterations to water quality and discharge. Furthermore, information on the structure of the ichthyofauna community, community spatial shifts and fine-scale habitat preferences for the region are lacking. Accordingly, the research sought to address this issue, to provide baseline data as well as inform on management of the system. Ichthyofauna were collected utilising an array of passive and active techniques and species data modelled to fit spatial factors to ascertain spatial shifts. To ascertain fine-scale habitat preferences, fourth-corner modelling was undertaken to link mouth position and body shape traits to substrate composition and cover features. Spatial heterogeneity in environmental characteristics caused by the intrusion of the African Rift Valley had driven significant spatial shifts in the ichthyofauna community, with distinct groups of species occurring within the sample sites. The findings of the study indicated that the ichthyofauna community within the Muazi River were significantly different to the Pungwe River and the community will be lost from the region because of the dam footprint. Furthermore, habitat preferences were influenced by mouth position and body shape. Consequently, alteration to environmental characteristics and habitat features is likely to negatively influence the ichthyofauna community. [ABSTRACT FROM AUTHOR]

Corexit EC9500A is an oil dispersant used prominently in the Deepwater Horizon spill both below water and on the ocean surface. Aquatic tests show that it has low toxicity to many crustaceans, corals and fish but is more toxic to plankton, daphnia and many species early life stages. Human health concerns found low acute toxicities but potentials for chronic effects with large exposures. Dispersant use should be based on many factors, of which toxicity is just one which should be considered. However, freshwater system toxicity requires more study before widespread use is recommended. [ABSTRACT FROM AUTHOR]

An extensive survey of tropical rivers, conducted during 2009-2012 throughout Zambia, collected 151 samples of benthic macroinvertebrates, located on 95 rivers in six of the nine freshwater ecoregions. Associated data for physico-chemistry, human activities and ecosystem stressors were collected. Data were used to develop and test a new Rapid Bioassessment Protocol (the Zambian Invertebrate Scoring System: ZISS) for assessment of water quality and river condition in both wadeable and non-wadeable rivers. ZISS, which is based on the South African Scoring System (SASS), includes a total of 85 taxa, of which 79 are shared with SASS. Assignment of sensitivity weightings to new ZISS taxa was based on sensitivity weightings of closely related SASS families; known life-history modes and anatomical adaptations; and correlation of occurrence to impact ratings. The ability of the ZISS to measure impacts was assessed by determining the relationships between ZISS metrics and impacts. ZISS data for the Kafue River demonstrated the efficacy of the ZISS for detecting moderate to high impacts on water quality and river condition. ZISS represents a major step in developing a user-friendly, widely applicable, macroinvertebrate-based biotic index, which can provide easily interpretable assessments of river condition for southern tropical African rivers. [ABSTRACT FROM AUTHOR]

Many tropical freshwater ecosystems are impacted by cyanobacteria blooms increasing the risk of cyanotoxins exposure to aquatic organisms while human populations may be exposed by eating fish, drinking water, or dermal swimming. However, few toxicological data are available on the influence of cyanobacteria blooms in particular, cylindrospermopsin (CYN) on Brazilian neotropical fish. A number of studies demonstrated the ability of CYN to bioaccumulate in freshwater organisms and consequently enter the human food chain. The aim of the current study was to examine the effects of CYN following single intraperitoneal injection (50 µg/kg) of purified CYN (CYNp) or aqueous extract of CYN-producing cyanobacteria extract (CYNex) after 7 or 14 days. Biomarkers such as histopathology (liver), oxidative stress (liver and brain), and acetylcholinesterase (AChE) activity (muscle and brain) were utilized in order to assess the influence of CYN on Hoplias malabaricus. In terms of AChE activity, administration of CYNex and CYNp both muscle and brains were used as target tissues. In brain an increase of glutathione S-transferase (GST) activity and lipid peroxidation (LPO) levels was noted suggesting an imbalance in redox cycling. The majority of biomarkers did not present significant alterations in liver, but an elevation in superoxide dismutase (SOD) and glucose 6 phosphate dehydrogenase (G6PDH) activities was found. Different profiles of GST activity were observed in both studied groups (CYNex and CYNp) while LPO (CYNex and CYNp) and protein carbonylation (PCO) (CYNp) levels increased after exposure to CYN. The incidence of necrosis, melanomacrophages centers, and free melanomacrophages were detected as evidence of cell death and immune responses. Nonprotein thiols (NPT) levels were not markedly affected in both exposed groups. Data demonstrated that in vivo exposure to CYN produced biochemical and morphological disturbances in liver and brain of H. malabaricus. [ABSTRACT FROM AUTHOR]

The interaction between surface water and groundwater in clay-rich fluvial environments can be complex and is generally poorly understood. Airborne electromagnetic surveys are often used for characterizing regional groundwater systems, but they are constrained by the resolution of the method. A resistivity imaging survey has been carried out in the Macquarie Marshes (New South Wales, Australia) in combination with water chemical sampling. The results have enabled the identification of buried palaeochannels and the location of potential recharge points. The data have been compared with previously published airborne electromagnetic data in the same area. Deeper less conductive features suggest that there is a potential connection between the Great Artesian Basin and groundwater contained within the shallow sand aquifer. Even though the chemistry of the groundwater samples does not indicate interaction with the Great Artesian Basin, the observed discontinuity in the saprolite implies potential for this to happen in other locations. [ABSTRACT FROM AUTHOR]

To understand acute toxicity and oxidative stress of perfluorinated compounds in the freshwater ecosystems, we exposed freshwater mussels (Unio ravoisieri) to perfluorooctane sulfonate (PFOS), over a range of concentrations from 10 to 100 mg/L, in a laboratory experiment. Lethal concentration (LC50) was of about 65.9 mg/L after 96 h of exposure. The oxidative stress was assessed in gill and digestive gland of the freshwater mussels after 7 days of exposure to different nominal PFOS concentrations (C1= 2 mg/L, C2 = 6 mg/L and C3= 10 mg/L). C1 and C2 increased significantly (p < .05) the superoxide dismutase activity in both tissues compared, while the highest C3 decreased the enzyme activity. This implements an unfavourable response that highlights the excess of reactive oxygen species produced after contamination. The Catalase activity was also increased by about 40.05% and 66.63%, respectively, in gill and digestive gland after exposure to C3. The Malondialdehyde (MDA) level was increased in both gill and digestive gland in a concentration-dependent pattern. In contrast, the contamination of U. ravoisieri by PFOS did not affect the acetylcholinesterase activity in both organs (p > .005). These results provided information on potential biomarkers that could be effectively applied for the monitoring of freshwater ecosystem using indicator species such as U. ravoisieri. [ABSTRACT FROM AUTHOR]

Microcystins (MCN), β-N-methylamino-L-alanine (BMAA) and anatoxin-a were investigated in Antarctic cyanobacterial mats collected from Ross Island and the McMurdo Ice Shelf, East Antarctica during Captain Scott’s ‘Discovery’ National Antarctic Expedition (1901-1904). Ultra-performance liquid chromatography-photodiode array detection (UPLC-PDA) and tandem mass spectrometry (MS/MS) analysis were used to quantify the cyanotoxins in seven cyanobacterial mat samples. MCNs were identified in six of the mat samples at concentrations from 0.5 to 16.1 µg g-1 dry weight. BMAA was found in one sample (528 ng g-1 dry weight, total BMAA), as well as two BMAA isomers, 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl) glycine (AEG) in six samples up to 6.56 and 6.79 μg g-1 dry weight, respectively. No anatoxin-a was detected. The findings confirm that MCNs, BMAA and BMAA isomers are preserved under dry herbarium conditions. The ‘Discovery’ cyanobacterial mat samples represent the oldest polar cyanobacterial samples found to contain cyanotoxins to date and provide new baseline data for cyanotoxins in Antarctic freshwater cyanobacterial mats from prior to human activity in Antarctica, the development of the ozone hole and current levels of climatic change. [ABSTRACT FROM AUTHOR]

Specimens of Aegla castro Schmitt, 1942 were monthly sampled from June 2012 to May 2013 from Couro stream (23°57′15″S 51°06′00″W), located in the Upper Paraná river region, southern Brazil. Population structure, morphometric and functional maturity were analyzed. Allometric growth analysis on chela dimension versus carapace length (CL) was employed to recognize juveniles and adult individuals. Two sequential groups of adult males (morphotypes I and II) were recognized according to the state of development of the pair of claws. The CL where 50% of the population of individuals are adults (CL50) was used to estimate the size at the onset of morphometric maturity. Males attain morphometric maturity at same size class of females (8.0-9.0 mm CL). Males and females are heterochelous and they often show the left chela more developed. The reproductive period was extended from June to September 2012 and April to May 2013 (six months) with record of 22 ovigerous females. The recruitment occurred in the months following the reproductive period, with higher records in October and December 2012. All the information gathered here should be useful to better understand the biology of the species studied. [ABSTRACT FROM AUTHOR]

Acid mine drainage (AMD) continues to threaten water quality in many mining regions globally. Data paucity renders it challenging to inform appropriate water quality management strategies for a succinct scientific understanding of the effects of AMD on freshwater ecosystems. The current study investigated the effects of AMD collected from a defunct coalmine in Mpumalanga, South Africa, on freshwater ecosystems using a risk-based approach on five indigenous species, Adenophlebia auriculata, Burnupia stenochorias, Caridina nilotica, Pseudokirchneriella subcapitata and Oreochromis mossambicus in 2016. Species responded differently to AMD after 96 hours and 240 hours of exposure in static experimental test designs. Burnupia stenochorias was more sensitive to AMD after 96 and 240 hours of exposure, whereas O. mossambicus was tolerant during short-term exposure, but became more sensitive after 240 hours of exposure than the other species tested. The availability of metals in AMD was directly associated with dilution rate. Scenario-specific water quality guidelines for AMD have been derived as 0.122% for short-term and 0.014% for long-term exposure. These may form important indicative dilutions for other AMDs that do not match the scenarios of this study. The toxicity of AMD to a wide range of aquatic species, including field validations, requires further investigation. [ABSTRACT FROM AUTHOR]

The world’s freshwater ecosystems, sources of drinking water, are threatened by eutrophication. Many studies show that global warming leads to changes in aquatic ecosystems. Recently, eutrophication signs have been recorded in Lake Baikal, the world’s largest and deepest lake containing 20% of the world’s fresh water reserves. We have analysed long-term changes of the most sensitive natural factors (air and water temperature, wind regime, precipitation and solar radiation) and revealed their potential impact on emergence of unfavourable signs in the shallow zone of Lake Baikal. The main causes of adverse ecological processes are elevated temperatures of air and coastal water, reduced amount of precipitation, weakening of wind flows, and water exchange processes, and as a result, reduced self-purification. The highest number of anomalous climate changes has been recorded in the XXI century. Moreover, the years of the past decade were the most favourable for emergence of adverse processes in the lake (outbreak of rapid growth of algae and aquatic vegetation, rotting of their remains at the bottom and on the shores of the lake, etc.). Climatic factors will continue causing adverse effects in the shallow zone of Lake Baikal. [ABSTRACT FROM AUTHOR]

We document the size diminution series and valve morphology of the diatom Naviculadicta parasemen Lange-Bertalot in Lange-Bertalot & Genkal, described originally from the Yugorsky Peninsula and nearby islands, northwest Siberia. Based on material from the northeastern Arctic, the features of the valve structure, undulate raphe with dilated external proximal raphe ends, organization of the striae, and change in orientation of the striae near the apices suggest a close affinity with the monotypic genus Rexlowea. We effect the transfer of N. parasemen to Rexlowea, making the new combination R. parasemen. Several features of R. navicularis, the generitype, are missing from R. parasemen, including septa and pseudosepta. It may therefore be necessary to emend the description of Rexlowea as additional species are referred to the genus, but we will await discovery of additional species before formal emendation. [ABSTRACT FROM AUTHOR]

Two new diatoms, Nitzschia fabiennejansseniana Cocquyt &Ryken sp. nov. and Nitzschia pseudoaequalis Cocquyt sp. nov., are described from Lake Challa, a deep crater lake in East Africa, based on light and electron microscopical observations. These Nitzschia species are morphologically similar to other needle-shaped, planktonic Nitzschia present in freshwater lakes of tropical Africa. The differences between the newly described species and related Nitzschia taxa are a combination of the shape of the poles, the number of striae and fibula in 10 µm, and the presence of a central gap between the fibulae. Nitzschia fabiennejansseniana is common in the plankton of Lake Challa towards the end of the main dry and windy season during the northern hemisphere summer, when deep water-column mixing causes upwelling of nutrient-rich hypolimnetic water. Together with Afrocymbella barkeri, this taxon is the dominant diatom in the pelagic phytoplankton of Lake Challa today, and has been continuously over at least the last several hundreds of years, as recorded in its sediments. The temporal dynamics of both taxa in Lake Challa play a major role in the interpretation of past climate change in equatorial East Africa. The other new taxon, N. pseudoaequalis, was common in some epilithic samples taken from the littoral zone of Lake Challa. It was also sporadically observed in the pelagic phytoplankton near the end of the mixing season. [ABSTRACT FROM AUTHOR]

TwoRhizocloniumstrains thriving in contrasting spring types (slightly hot spring/ambient, shaded pool spring) and biogeographic areas (El-Farafra Oasis in the Western Desert of Egypt/River-Po Plain in Northern Italy) were studied in depth based on field and cultured material, bright-field and fluorescence microscopy, and phylogenetic molecular analyses (SSU and LSU rRNA gene sequences). This polyphasic approach revealed that the twoRh. strains clearly belonged to theRhizocloniumclade but differed in some of their key diagnostic features. The EgyptianRhizocloniumstrain, isolated from the spring-fed (Ain El-Balad) agricultural ditch in El-Farafra Oasis, was described with the working name ‘Rhizocloniumsp. 10.6 μm from a desert, slightly-hot spring’ based on its smaller cell diameter, ecological and phylogenetic molecular traits compared to allied morphospecies. Moreover, it was highlighted that the L/D ratio can be more than 3.0 within this group. The ItalianRhizocloniumstrain, collected from the Fontanile Valle Re-shaded, pool ambient spring (Emilia-Romagna Region), was virtually identical to other strains identified asRh. hieroglyphicumfrom China and Japan, due to its highly supported congruence in morphological characteristics and phylogenetic position. This study provided the first partial LSU and SSU rRNA gene sequences for EuropeanRh. hieroglyphicumbased on available literature. Phenotypic plasticity of rhizoid formation was also observed in bothRhizocloniumstrains studied using culturing approaching techniques. Our investigation also confirms that a lot of work with a variety of approaches is still needed to assess the ecological preferences, morphological plasticity, and phylogenetics of freshwaterRhizocloniumtaxa worldwide. [ABSTRACT FROM PUBLISHER]

Aspects of reducing the resource potential of surface waters of the Murmansk region in the global climate change and the environment and their irrational use have been considered. Increase of aquatic environment toxicity, drastic restructuring of the structural and functional characteristics of aquatic communities, changes in trophic status of lakes, reducing the stability of freshwater ecosystems, increasing the risk of catastrophic degradation have been shown. Taking into account the regional peculiarities, some indicators of surface water quality in the Murmansk region have been proposed. [ABSTRACT FROM PUBLISHER]

Temnocephalida, a group of small epibiontic worms strictly associated with freshwater hosts, includes 179 taxa in 23 genera, classified in two major groups: Scutarielloidea, distributed in the Palaearctic region, and Temnocephaloidea distributed mainly in the Australian and Neotropical regions. Based on a large-scale spatio-temporal dimension, a biogeographic hypothesis on a Gondwanan scenario was tested. The objective of this study was to describe the geographic distribution patterns of Temnocephalida in a primary biogeographic homology context. A dataset of 793 temnocephalan records, distributed in 45 hydrological basins, and assigned to different hierarchical taxonomic levels was used to construct five presence/absence matrices. We analysed the matrices using Parsimony Analysis of Endemicity (PAE) and Cladistic Analysis of Distributions and Endemism (CADE). Furthermore, we constructed generalized tracks based on area clades with phylogenetic support, i.e., two or more synapomorphies. Six generalized tracks were revealed: a general clade for Eurasia, plus a complex of four hybrid zones with monophyletic relationships included in a major clade with Gondwanan affinities. The results represent the first study using biogeographic analysis to disentangle the distributional patterns of temnocephalids around the world. Based on the integration of the results obtained by biogeographic pattern-based methods, we infer that the fragmentation of Gondwana affected the diversification patterns and distribution of Temnocephalida. [ABSTRACT FROM PUBLISHER]

Water is essential to life. Current urban water systems often degrade freshwater ecosystems, nature’s ability to replenish resources and the relationship between people and the environment. To address this, integrated urban water management (IUWM) has been developed; yet, is too often undermined by institutional paralysis and a subsequent lack of physical change in cities. This paper presents key learnings from research undertaken to understand how spatial planning can be utilized as a tool in IUWM; where hydrological systems influence the form and structure of cities. The intention is to improve water literacy in urban planning where complex conditions confront urban and natural systems. This research culminates in a theoretically considered spatial water framework (SWF) for the City of Cape Town to guide appropriate and innovative intervention in the urban water system. The SWF envisions Cape Town transitioning to an increasingly water-secure future as facilitated through nurturing a reverence for water; enabling restoration of water systems through ecological alignment; embracing restraint towards water use; and cultivating responsibility to develop good water stewards. Therein lies the opportunity for a closer integration of planning for urban development and water systems while reconciling the human–nature relationship. [ABSTRACT FROM AUTHOR]

Ezemvelo KwaZulu-Natal Wildlife embarked on a programme to identify all the estuaries within the KwaZulu-Natal (KZN) province. Following an aerial survey along the coastline in 2012, images of all the visible inlets and estuaries were captured. Among these are a number of areas where flows of freshwater to the sea appeared to be present but which were not among the estuaries that had previously been named. There are already well defined and recognised estuary types being managed in South Africa in terms of existing environmental legislation. Following the initial survey and the observation that there are coastal inlets/freshwater outlets that are potentially small estuaries that had not been included among them prompted a further investigation into whether some of these inlets were in fact features that should be classified in some way or other. Based on a rapid qualitative assessment, 181 sites were classified as either a “micro-estuary”, “freshwater seep”, “hard-structure freshwater outflow point” or as sites that had been considerably modified by engineered structures. A total of 61 of these 181 sites are included in a new classification as micro-estuaries. Most of these systems are in a degraded condition and require intensive rehabilitation to restore them to their historical ecological function. This study emphasises the urgency of accepting “micro-estuary” as a new estuarine type to provide formal protection against further deterioration. This is the first study to provide a description and spatially define these smaller systems present along the KZN coast. [ABSTRACT FROM PUBLISHER]

Type-specific stream assessment systems based on biotic indicators are considered a main focus of future stream assessment in many European countries. However, there is a lack of information on type-specific differences of freshwater eco-regions in South Korea. We aimed to classify the stream types characterized by stream size and altitude. Analyzing the relationship between physical environmental variables and benthic macroinvertebrates collected between 2008 and 2015 at 1,020 sites (i.e. 13,366 samples) on a national scale in South Korea, we classified a total of five Korean stream types. All streams were divided into wadeable and non-wadeable streams using stream order and width. Wadeable streams were classified as mountain, highland, or lowland wadeable streams based on altitude. Non-wadeable streams were divided into lowland non-wadeable streams or rivers based on width. Mountain and highland streams significantly correlated with altitude, whereas others were distinctly related to stream order and width. We selected 25 indicator species sensitive to stream size and altitude. These assessments will provide preliminary information for development of a future biotic stream assessment system based on stream typology. [ABSTRACT FROM AUTHOR]

Freshwater input is known to have the potential to influence marine pelagic and benthic communities through the export of nutrients, sediments and detritus. The increase in nutrients of riverine origin in coastal environments can enhance primary production in coastal areas, supporting a diverse and rich fauna. However, it is not clear how and to what extent these freshwater inputs influence marine populations. We investigated the potential effects of freshwater input on the diets of intertidal benthic organismsin situon the east coast of South Africa, analysing their δ13C and δ15N stable isotope and fatty acid content. Specifically, we investigated the dietary regime of three barnacle and one mussel species in relation to their proximity to the mouths of large rivers. Strong dissimilarities among species were recorded with both techniques; however, no significant effect of freshwater input was observed for any of them. There are several possible explanations for these results, including rapid dilution, with fresh water near the river mouth being thoroughly mixed with seawater, resulting in a riverine influence being too weak to be detectable in the signatures of benthic populations. Our results contrast with a previous study conducted in the same area, where it was suggested that demersal organisms relied on freshwater-derived organic matter. Our study, however, showed no freshwater effect either within a few metres or tens of kilometres from the nearest large river mouths, supporting the notion that freshwater input does not play an important role for the benthic intertidal community in the ecosystems studied. Given that freshwater input is likely to diminish in the future, because of increased human abstraction of water, any potential effects of freshwater input on these marine populations are likely to be further reduced. [ABSTRACT FROM PUBLISHER]

Cyanobacterial blooms have increased in freshwater ecosystems worldwide in the last century, mostly resulting from eutrophication and climate change. These blooms represent serious threats to environmental and human health because of the production of harmful metabolites, called cyanotoxins. Like many countries, Egypt has been plagued with cyanobacterial blooms in most water sources, including the Nile River, irrigation canals, lakes and fishponds. However, the data about cyanotoxins produced in these blooms are limited. Only two types of cyanotoxins, microcystins and cylindrospermopsin, have been identified and characterised, mainly fromMicrocystisandCylindrospermopsisblooms. The data revealed the presence of microcystins in raw and treated drinking waters at concentrations (0.05–3.8 µg l−1), exceeding the WHO limit (1 µg l−1) in some drinking water treatment plants. In addition, Nile tilapiaOreochromis niloticuscaught from ponds containing heavy cyanobacterial blooms have accumulated considerable amounts of cyanotoxins in their edible tissues. The data presented here could be the catalyst for the establishment of a monitoring and management programme for harmful cyanobacteria and their cyanotoxins in Egyptian fresh waters. This review also elucidates the important research gaps and possible avenues for future research on cyanobacterial blooms and cyanotoxins in Egypt. [ABSTRACT FROM PUBLISHER]

Sampling emergent aquatic insects is of interest to many freshwater ecologists. Many quantitative emergence traps require the use of aspiration for collection. However, aspiration is infeasible in studies with large amounts of replication that is often required in large biomonitoring projects. We designed an economic, collapsible pyramid-shaped floating emergence trap with an external collection bottle that avoids the need for aspiration. This design was compared experimentally to a design of similar dimensions that relied on aspiration to ensure comparable results. The pyramid-shaped design captured twice as many total emerging insects. When a preservative was used in bottle collectors, >95% of the emergent abundance was collected in the bottle. When no preservative was used, >81% of the total insects were collected from the bottle. In addition to capturing fewer emergent insects, the traps that required aspiration took significantly longer to sample. Large studies and studies sampling remote locations could benefit from the economical construction, speed of sampling, and capture efficiency. [ABSTRACT FROM AUTHOR]

We investigated the response of the invertebrate drift to the regulated peaking Magpie River under experimental sub-hourly changes in flow conditions. Benthic invertebrates were also quantified upstream of invertebrate drift sampling sites in order to examine the propensity of nearby invertebrates to drift under hydropeaking cycles. To provide an understanding of the natural patterns of drift in relation to changes in discharge, the proximate natural Batchawana River was similarly sampled. Increased discharge was associated with higher drift densities and greater particulate organic matter in the Magpie River. At the family level, multiple drift responses were observed suggesting that ecological traits and behaviors drive drift response to changes in discharge. The drift densities of some invertebrates varied in proportion to discharge; whereas, other invertebrates in the drift decreased to pre-peaking levels shortly after peak discharge was reached, with some invertebrates exhibiting a secondary peak in density as discharge returned to pre-peaking levels. Although average drift densities were comparable between the two rivers, drift density on the natural Batchawana River was much more stable than that of the Magpie River. Changes in drift density associated with flow manipulation likely impact feeding patterns and behavior of drift feeding fish. [ABSTRACT FROM PUBLISHER]

Systematic studies on the closely related red algal species of Caloglossa, C. beccarii, C. fluviatilis and C. stipitata, were conducted because the morphological and phylogenetic distinction of the three species was not resolved previously. The large-subunit ribosomal DNA or rbcL gene analyses revealed that specimens from Indian freshwater rivers and German and Ukrainian freshwater aquaria form a clade with C. fluviatilis from the Panama Canal, and this clade is distinct from C. beccarii and C. stipitata. Caloglossa fluviatilis was morphologically distinguished from the other two species by the smaller number of cells in a second-order row at the internode, the narrower blade, smaller number of rhizoids at the node, and fewer rhizoids produced from wing cells. The number of rhizoids at the node and the ratio of internodal blade length to upper blade width were useful to delineate the three species. Low-molecular-weight carbohydrate analyses revealed that strains from freshwater habitats as well as brackish habitats contain both the C-6 polyol mannitol and the heteroside digeneaside. The present study confirmed the distinctness of the three species, and this is the first report of C. fluviatilis from other than the type locality. [ABSTRACT FROM AUTHOR]

In drinking water, arsenic (As) food chain accumulation may pose a risk to human health. An attempt was made to synthesise the published information concerning As trophic transfer along the food chain/web of various marine, freshwater, and terrestrial ecosystems. Some investigations included As speciation. Further objectives were to outline the factors potentially influencing As trophodynamics and to understand the consequence of As trophic transfer in the environment. [ABSTRACT FROM AUTHOR]

The archaeology of the arid and apparently inhospitable spinifex plains of today’s inland Pilbara, Western Australia, is dominated by sites with bedrock grinding patches. These range from single and sometimes barely visible areas of ground granite to sites with more than a hundred flat, slightly concave or sometimes deeply grooved ground patches. Sometimes a solitary feature, sometimes associated with engravings or scattered stone artefacts, these sites contribute to the story of the movement of people through this arid landscape. But what do they tell us? Using ethnohistorical, ethnographic and experimental studies, this paper evaluates data collected from sites with bedrock grinding patches recorded on the Abydos Plain. Our results highlight the need for ‘grinding’ patches to be reconsidered as more than ‘grinding’ patches, for better modelling of freshwater ecology and inland fishing, and for the potential of spinifex fibre technology to be actively incorporated into reconstructions of hunter gatherer lifeways in arid landscapes. [ABSTRACT FROM PUBLISHER]

Ten locations in the Notranjska region, Slovenia, with different land use in the catchment (town, village and agricultural areas), including reference points with different geological composition considered as unpolluted sites, were sampled for water and aquatic moss to evaluate environmental assessment in fresh water systems of the Sava River watershed. Samples of fresh water andFontinalis antipyreticawere taken in all four seasons during the years 2010 and 2012. The water chemistry of the investigated locations was dominated by, while concentrations ofseasonally ranged from 2.1 to 6.4 mg L−1and at one of the reference sites did not exceed 1.3 mg L−1. δ13CDICvalues seasonally ranged from −13.3 to −8.1 ‰ and indicated waters dominated by degradation of organic matter and dissolution of carbonates. δ13Cplantvalues ofF. antipyreticaseasonally ranged from −45 to −32.9 ‰ and of δ15Nplantfrom −0.2 to 6.5 ‰. The higher δ15N value of 6.5 ‰ found inF. antipyreticawas related to agricultural activity in the watershed. The content of minor and trace elements inF. antipyreticaranged from 4–38 µg g−1for Ni, 17–105 µg g−1for Zn, 2–28 µg g−1for Pb, 0.26–1.95 µg g−1for Cd, 4–27 µg g−1for Cu, 4–49 µg g−1for Cr, 1–6 µg g−1for As and 0.33–3.24 µg g−1for Se. The most polluted watershed was the Pšata stream (agricultural area, cattle farm with the highest concentration of nitrate in water) also with highest values for Ni, Cr, Pb, Zn and As. [ABSTRACT FROM PUBLISHER]

The present study was undertaken to obtain a better understanding of the seasonal variability of total dissolved metal/metalloid levels and physicochemical parameters within small- to medium-size freshwater ecosystems in temperate climate region. The research was conducted in four seasons in the Sutla River, medium-size polluted, and the Črnomerec Stream, small-size unpolluted watercourse in Croatia. In the Sutla River, characterized by the rural/industrial catchment, physicochemical parameters and total dissolved metal concentrations of 21 trace and 4 macro elements were analysed downstream of the point source of pollution, the glass production facility, indicating for the first time their variability across four seasons. Based on dissolved oxygen, total dissolved solids, nutrient concentrations, conductivity and total chemical oxygen demand, quality status of the Sutla River was good, but moderate to poor during summer, what was additionally confirmed by the highest levels of the most of 25 measured metals/metalloids in summer. Comparison with the reference small-size watercourse, the Črnomerec Stream, indicated significant anthropogenic impact on the Sutla River, most evident for Fe, Mn, Mo, Ni, Pb, Rb and Tl levels (3-70-fold higher in the Sutla River across all seasons). Generally, presented results indicated significant decrease of the water quality in the anthropogenically impacted small- to medium-size watercourses in summer, regarding physicochemical water parameters and total dissolved metal/metalloid concentrations, and pointed to significant seasonality of these parameters. Confirmed seasonality of river ecological status indicates that seasonal assessment represents a prerequisite for proper classification of the water quality in small- to medium-size temperate rivers. [ABSTRACT FROM PUBLISHER]

Global data sets are essential in macroecological studies. File formats of the few available data sets of freshwater ecosystems, however, are either incompatible with most macroecological software packages, incomplete, or of coarse spatial resolutions. We integrated more than 460 million geographical coordinates for freshwater habitats in the FRWater data set, partitioned into seven different habitats (lentic, wetlands, reservoirs, small rivers, large rivers, small ditches, large ditches, small channels, large channels, small drains and large drains) in ModestR (http://www.ipez.es/ModestR). A comprehensive collection of geospatial rasters was assembled, one for each of the seven freshwater habitats, with the area in km2occupied by each habitat presented in cells of 5 arc-minute resolution. The utility of FRWater was evaluated using hierarchical partitioning via the identification of the contribution of the seven different freshwater habitats to both species richness and rarity. To this end, we used a data set of 836,123 geographical records of the 16,216 species of freshwater fishes recognized as valid by systematists at the end of 2014. Areas in North America and Europe are the most detailed in the FRWater data set, evidencing the higher quality of data sources in those regions. The number of geographical coordinates is much lower for Africa, Asia, Australia, and South America where many water bodies remain unmapped. In light of the variation in information quality at continental levels, we performed and present comparative analyses for Europe versus South America at local (5ʹ × 5ʹ grid cells) and regional (5° × 5° grid cells) scales. The relative contribution of small rivers to both species richness and rarity was highest under almost all analyses, followed by lentic habitats and large rivers. The areas of different habitats moreover explained a relatively high proportion of the observed variance in geographic rarity. Our findings corroborate previous findings that the greater contribution of small rivers to species richness is probably due to these habitats promoting geographical rarity. Hence, species richness is favored by the isolation resultant from, and the refuges associated with, small river basins and via the diversification processes promoted by such isolation. [ABSTRACT FROM PUBLISHER]

Information on the freshwater microcrustaceans of the remote arctic islands is very limited. The species composition of freshwater zooplankton and meiobenthos of Wrangel Island (Russia) is reported here for the first time. We identified five species of Cladocera, and 20 species of Copepoda. Twenty-three taxa are new records for the island. Additionally, we discuss the taxonomy of some species with doubtful taxonomical status. We also analysed data from other arctic and subarctic territories to compare with that of Wrangel Island and evaluate the latitudinal trends of species richness and distribution of Cladocera and Copepoda and their relation to environmental factors. The effects of different environmental factors were statistically examined to establish which are important in controlling distributional patterns and diversity of species. On Wrangel Island the fauna of microcrustaceans is primary controlled by three factors: low temperatures, the remoteness from the nearest mainland and geological history of the island – its relation to ancient Beringia and lack of Pleistocene glaciation. [ABSTRACT FROM AUTHOR]

Various waterborne anthropogenic contaminants disrupt the endocrine systems of wildlife and humans, targeting reproductive pathways, among others. Very little is known, however, regarding the occurrence of endocrine disruptive activity in South African freshwater ecosystems, and coastal ecosystems have not been studied in this regard. In a first attempt to investigate endocrine disruptive activity in South African coastal waters, surface water samples collected from harbours, river mouths and estuaries in three metropolitan municipalities, eThekwini (which includes Durban), Nelson Mandela (specifically Port Elizabeth Harbour) and City of Cape Town, were screened for (anti) oestrogenicity and (anti)androgenicity using recombinant yeast bioassays. Moreover, levels of the female hormone 17β-(o)estradiol (E2) were determined in all samples, as well as a selection of hydrocarbons in the eThekwini samples. A high proportion of samples collected from eThekwini were oestrogenic, whereas none from Port Elizabeth Harbour and only a single river mouth sampled in the City of Cape Town were oestrogenic. E2 was detected in all the samples tested, but at higher concentrations at the eThekwini and City of Cape Town localities than Port Elizabeth Harbour. In addition, the recombinant yeast assays revealed that anti-androgenicity was widespread, being detected in the majority of samples screened apart from those representing Port Elizabeth Harbour. Conversely, no anti-oestrogenic or androgenic activity was detected. Anti-androgenicity did not associate with hydrocarbon loads, providing evidence that other anti-androgens were responsible for the observed activity. The present data suggest potential reproductive disruption in marine and estuarine fauna inhabiting the eThekwini and City of Cape Town regions. [ABSTRACT FROM AUTHOR]

Hydrothelphusa vencesiis an endemic Madagascan freshwater crab whose ecology and behaviour are largely unknown. We report here on an episode of the feeding habits of two individuals ofH. vencesion a giant fire millipede (Aphistogoniulus infernalis) and on a cicada (Malagasia inflata) in south-east Madagascar. This represents a first report on the diet of this species and an example of its opportunistic feeding behaviour, shedding some light on the possible trophic link between an aquatic and a terrestrial system. [ABSTRACT FROM AUTHOR]

The shore of Lake St Lucia in the vicinity of Catalina Bay, in the southern part of the lake, receives freshwater input as surface and groundwater seepage from the adjacent elevated coastal plain. Vegetation, water quality and landform were recorded on the lakeshore and on the dry lakebed near one of these seepage zones. This was done along a gradient perpendicular to the lakeshore and along the lakeshore away from the fluvial source of freshwater input. A number of plant communities were found along a gradient of water salinity from the shoreline (fresh water) towards the centre of the lake, and also away from the fluvial input of water (increasingly saline). Species richness decreased with increasing salinity. The first study was conducted in 2006 after a prolonged drought associated with low lake levels and closure of the mouth, and repeated again in 2010 three years after breaching of the estuarine mouth by a tropical cyclone at sea, which caused inundation of the partly dry lakebed with sea water. The vegetation of the lakeshore after these major disturbances was remarkably similar in the two time periods, suggesting rapid recovery near freshwater seepage zones, following an influx of sea water. [ABSTRACT FROM AUTHOR]

Kidneys are important organs that play a role in ion and water regulation in different aquatic environments. The Van fish (Alburnus tarichi,Güldenstädt, 1814) has acclimated to the alkaline waters of the largest saline soda lake in the world. In this study, changes in kidney tissue were examined histologically in alkaline and freshwater as the fish entered freshwater for reproduction. In addition, immunological changes were examined for Na+, K+, ATPase (NKA), an important transmembrane protein in kidneys. A histological comparison of the kidneys of fish taken from both environments was made. The glomerular volume was larger in fish acclimated to freshwater, and the collecting tubules were larger in diameter and had thicker walls. The fish acclimated to alkaline lake water had reduced numbers of glomeruli of smaller size. NKA enzyme was present in tubules within kidneys in both environments. It was, however, observed more frequently in fish acclimated to freshwater. Although plasma osmolality and Cl−values decreased in the fish acclimated to freshwater, hematocrit values increased (p < 0.05). No changes were observed in the muscle water content between alkaline water- and freshwater-acclimated fish. We clearly demonstrate that histologic and immunochemical changes take place in the kidney of the Van fish acclimated to the different physicochemical characteristics of alkaline and freshwater environments. [ABSTRACT FROM AUTHOR]

This report includes a detailed description of the reproductive behaviour of the freshwater crabZilchiopsis collastinensisin the family Trichodactylidae and some observations on two other genera. It presents observations on the courtship, copulation, spawning, incubation and maternal care inZ. collastinensis. No discernible courtship behaviour occurred. We found instead that forced copulation is practised by males.Z. collastinensiscopulations were observed in between April and October, forDilocarcinus pageibetween January and August, and throughout the year forTrichodactylus borellianus. The spawning behaviour of all of the species observed took place out of the water. Incubation lasted between 46 and 62 days inD. pagei, 37 and 41 days inZ. collastinensisand 8 and 12 days inT. borellianus. The number of juveniles carried by each ovigerous female ranged from 651 ± 172 inZ. collastinensis, through 582 ± 8 inD. pageito 63 ± 33 inT. borellianus. The results support the proposition that members of the family Trichodactylidae, comprising exclusively endemic freshwater crabs, have evolved unusual adaptive reproductive behaviours to optimize their reproductive fitness in unstable environments. [ABSTRACT FROM AUTHOR]

Invasive round gobyNeogobius melanostomusand bighead gobyPonticola kesslerihave successfully colonized freshwater and coastal habitats worldwide. The objective was to use stable isotope analyses to study the foraging and movement of both species at small spatial scales in the Upper Danube River, considering 861 samples from two different years, seasons and sides of the river in an area where limited mixing at a confluence occurs. A difference in δ13C of 1 ‰ between gobies from both river sides was observed in both species and reflected the isotope spacing in their dominant benthic preyDikerogammarus villosus. These results suggest an absence of goby movement across the Danube River which was unexpected, given the fast spread of gobies at invasion fronts. It can be concluded that their dispersal is highly preferential with longitudinal movement likely being facilitated by artificial rip-rap structures along river banks, which provide shelter and food. [ABSTRACT FROM AUTHOR]

Lake Taihu is subject to severe eutrophication due to high nutrient inputs. We compared the macrozoobenthic assemblages of Lake Taihu in 1987–1988 and in 2007. Changes in benthic communities between the two periods were significantly different among the four lake regions (the River Mouth, the North Bay, the Open Lake, and the East Bay), corresponding well with the changed environmental conditions. The River Mouth and North Bay showed the greatest changes in benthic fauna, corresponding with severe degradation in water quality. In 1987–1988, benthic communities were dominated by Tubificidae and Bivalvia in the River Mouth and the North Bay, respectively. In 2007, however, benthic fauna were mainly dominated by Tubificidae in the North Bay and total macrozoobenthos increased approximately 18-fold in abundance. The Open Lake was dominated by bivalves (mainlyCorbicula fluminea) in both sampling periods, whereas an increased abundance of bivalve was observed from 1987–1988 to 2007. In the East Bay, which was covered by abundant macrophytes, the macrozoobenthos community decreased in abundance and was characterized by high species richness of gastropods. In addition, the abundance of gastropods, tubificids, and chironomids increased significantly between the two sampling periods. The relatively stable ecological conditions in the East Bay (e.g., trophic state and spatial distribution of macrophytes within the East Bay) might be responsible for the relatively small changes. Our results showed complex variation patterns of macrozoobenthic assemblages among different sections of Lake Taihu, which may be associated with the great environmental heterogeneity in this large shallow lake. [ABSTRACT FROM AUTHOR]

Subarctic peatlands are rich sources of organic carbon for freshwater ecosystems. Where those peatlands are underlain by permafrost, permafrost thaw may cause an initial release of bioavailable dissolved organic carbon (DOC) to surrounding freshwaters. In this study, we measured icebound and potentially leachable (extracted) DOC quantities and indices of DOC quality in active layer and permafrost layers from two subarctic peat mires, Stordalen and Storflaket. Most of the permafrost layers did not contain more organic matter or exportable DOC (as g kg-1 dry soil) than the overlying active layer, and there was no difference in aromaticity, molecular weight, or the ratio between labile and recalcitrant DOC extracted from the permafrost and active layer. However, DOC held in segregated ice of the near-surface permafrost had relatively low aromaticity compared to extracted DOC from the same depth. Total icebound and potentially leachable DOC in the Stordalen mire permafrost that is predicted to experience active layer deepening during each of the next 50 years corresponded to about 0.1% of the current annual aquatic export of DOC from the mire. We conclude that the pool of potentially leachable DOC currently stored in permafrost layers is small. We also highlight differences in permafrost organic material between the two studied mire systems, which has an effect on the pool and properties of leachable DOC that is potentially available for export during thaw. Moreover, the geomorphological form of permafrost thaw will influence future hydrological connectedness and DOC production, in turn determining future DOC export from the mires. [ABSTRACT FROM AUTHOR]

The control of most of Earth's freshwater resources with millions of tons of concrete underpins the modern world. This concrete is the physical manifestation of historical political choices about the use and value of ecosystem benefits, the context for current management challenges, and the point of departure for decisions on the future of water resources. Water resource systems, despite the emphasis on the engineered marvels that grab our attention, are perhaps best understood as a set of interconnected political calculations. This article examines the purpose of infrastructure in social–ecological systems and the importance of history and institutional permanence. It explores the political effects of water system infrastructure, the potential redistributive consequences of climate change, and why policy regimes and institutional arrangements will prove resistant to change. [ABSTRACT FROM AUTHOR]

Largemouth bassMicropterus salmoidesare among the world's 100 worst invaders and negatively affect aquatic biodiversity in many regions worldwide. In South Africa there is a paucity of empirical studies describing their impacts. The impact ofM. salmoideson the fish community in the Groot Marico River catchment, an otherwise near-pristine river ecosystem and a freshwater ecosystem priority area, was assessed from surveys conducted in 2012. Fish presence and abundance were enumerated using multiple survey techniques, and their association with key habitat variables and the presence or absence ofM. salmoideswere assessed. A total of 14 native fish species were recorded, besides introducedM. salmoides, which occupied the majority of the mainstem and several tributaries downstream of barriers to upstream movement. Canonical correspondence analysis showed that only one native species, the Marico barbBarbus motebensis, had a negative spatial association withM. salmoides. Assessment of relative distributions showed this species to be excluded fromM. salmoides-invaded river reaches, whereas the other native species were not visibly affected by the invader. This species-specificity of the impact ofM. salmoidesindicates that their impacts in South African streams may be dependent on predator-naiveté of prey. [ABSTRACT FROM AUTHOR]

Biological and physico-chemical factors affecting abundance and biomass of shrimpPalaemon peringueyiwere investigated in 2010–2011 in the lower, middle and upper reaches of the freshwater-deprived permanently open Kariega Estuary. Shrimp abundance and biomass ranged from 0 to 88 ind. m−2and 0 to 4.4 g wwt m−2, respectively. Shrimps were most abundant in the lower reach, and highest abundances and biomasses were recorded in the lower reach in June when salinities were low. The shrimps were almost always absent in the upper reach. Juveniles were found mostly in the lower and middle reaches, whereas adults were distributed in all three reaches. Regression analyses showed no statistically significant relationship for either abundance or biomass of the shrimps with temperature, salinity and dissolved oxygen (p> 0.05). The relationship between shrimp abundance and biomass and vegetation cover was positive and statistically significant (R2= 0.109 and 0.185, respectively;p< 0.05). Vegetation cover plays an important role in determining the presence, distribution and abundance or biomass ofP. peringueyiin this estuary. [ABSTRACT FROM AUTHOR]

Droughts act as significant disturbances to freshwater animals and their ecosystems. Given the impending threat of more frequent and persistent droughts because of global climate change, the lack of data on the responses of many aquatic animals to drought is a cause for concern. This study examined the body condition of the most commonly detected species (Desmognathus quadramaculatus) and abundance of commonly found species after two years of experimental drought in two first-order streams in the southern Appalachian Mountains. Our results indicated negative effects of drought on the stream salamander community. The body condition ofD. quadramaculatuslarvae in experimental drought transects was significantly lower than larvae captured in control reaches, which may have resulted from lower macroinvertebrate production in experimental reaches. Additionally, larvalD. quadramaculatusabundance declined 47% in experimental drought transects, andEurycea wilderaelarvae andD. ocoeeadults were 70% less likely to be captured in experimental stream transects. Our findings contribute additional evidence that stream plethodontids have little resistance to drought. With extended droughts resulting from climate change more likely in the future, more research is necessary to determine if reduced body condition, production, and lowered abundance have effects on long-term population viability. [ABSTRACT FROM AUTHOR]

Studies on freshwater invertebrate fauna on islands are rare but a few suggest species richness can be high. A survey of the freshwater invertebrates of Lord Howe Island (LHI) yielded 38 taxa, bringing the total recorded from LHI to 54. The majority of the taxa from the survey were from the Insecta, with 15 Diptera (true flies), five hemipterans (true bugs) and five trichopterans (caddisflies). Two species of gastropods, three mites and eight other arthropods were also found. The total number of taxa on LHI, although smaller than other islands, is the highest per unit area ever recorded (3.9 taxa per km2). High levels of endemism were recorded for most taxonomic groups and two previously undescribed chironomid species were found. However, further taxonomic and genetic work is necessary in order to assess true levels of endemism by investigating the genetic similarities and differences of these taxa with nearby islands. [ABSTRACT FROM AUTHOR]