Over recent decades, Chinese giant salamanders Andrias spp. have declined dramatically across much of their range. Overexploitation and habitat degradation have been widely cited as the cause of these declines. To investigate the relative contribution of each of these factors in driving the declines, we carried out standardized ecological and questionnaire surveys at 98 sites across the range of giant salamanders in China. We did not find any statistically significant differences between water parameters (temperature, dissolved oxygen, ammonia, nitrite, nitrate, salinity, alkalinity, hardness and flow rate) recorded at sites where giant salamanders were detected by survey teams and/or had been recently seen by local respondents, and sites where they were not detected and/or from which they had recently been extirpated. Additionally, we found direct and indirect evidence that the extraction of giant salamanders from the wild is ongoing, including within protected areas. Our results support the hypothesis that the decline of giant salamanders across China has been primarily driven by overexploitation. Data on water parameters may be informative for the establishment of conservation breeding programmes, an initiative recommended for the conservation of these species.

Lentic freshwater habitats are important centres of biodiversity within the infrequent ice-free oases across Antarctica. Given imminent climate changes, it is crucial to catalogue these habitats in order to provide baseline data for future monitoring and biological surveys. The lacustrine systems of Clearwater Mesa, a previously unexplored part of James Ross Island, north-eastern Antarctic Peninsula, are described here. We conducted basic geomorphological and limnological surveys over three Antarctic summers (2009–16) to characterize landscape evolution, infer the origin of lake basins and assess the variability in their water chemistry. Stable shallow lakes, formed in depressions between lava tumuli following the last deglaciation, were found to dominate the volcanic mesa, although several peripheral lakes in ice-proximal settings appear to have formed recently as a result of post-Neoglacial ice recession. We found large heterogeneity in conductivity (~10–7000 μS cm−1), despite the lithologically uniform substrate. This variability was shown to be related to lake type, basin type (open vs closed), meltwater source and proximity to the coast. Inter-annual differences were attributed to changes in sea spray influx and snow accumulation driven by variable weather conditions. Overall, the ion composition of lakes suggested that sea spray was the dominant source of ions, followed by the weathering of bedrock.

A new GIS-based screening tool to assess threats to shallow groundwater quality has been trialled in Glasgow, UK. The GRoundwater And Soil Pollutants (GRASP) tool is based on a British Standard method for assessing the threat from potential leaching of metal pollutants in unsaturated soil/superficial materials to shallow groundwater, using data on soil and Quaternary deposit properties, climate and depth to groundwater. GRASP breaks new ground by also incorporating a new Glasgow-wide soil chemistry dataset. GRASP considers eight metals, including chromium, lead and nickel at 1622 soil sample locations. The final output is a map to aid urban management, which highlights areas where shallow groundwater quality may be at risk from current and future surface pollutants. The tool indicated that 13% of soil sample sites in Glasgow present a very high potential threat to groundwater quality, due largely to shallow groundwater depths and high soil metal concentrations. Initial attempts to validate GRASP revealed partial spatial coincidence between the GRASP threat ranks (low, moderate, high and very high) and groundwater chemistry, with statistical correlation between areas of high soil and groundwater metal concentrations for both Cr and Cu (r2>0.152; P<0.05). Validation was hampered by a lack of, and inconsistency in, existing groundwater chemistry data. To address this, standardised subsurface data collection networks have been trialled recently in Glasgow. It is recommended that, once available, new groundwater depth and chemistry information from these networks is used to validate the GRASP model further.

We examined the associations of microorganism assemblages with a complete mineral richness gradient spanning from extremely mineral-rich tufa-forming calcareous fens to mineral-poor acidic Sphagnum-fens. We also compared the distribution of two dominant taxa, testate amoebae and monogonont rotifers, among the sites differing in water chemistry and among three microhabitats sampled at each site differing in substrate and moisture conditions. Microorganism assemblages primarily changed in relation to the mineral richness gradient; moisture was the second most important factor structuring microorganism assemblages among microhabitats (i.e., wet bryophytes, submerged bryophytes and waterlogged bottom sediments). Densities of testate amoebae taxa and individuals were the highest in rich Sphagnum-fens, indicating a unimodal pattern along the mineral richness gradient. Numbers of testate amoebae taxa decreased notably in wet bryophytes, especially in poor Sphagnum-fens. This pattern might result from a strong effect of Sphagnum acidification due to minimal or no dilution of the acidic environment by mineral-rich groundwater. As a consequence, acid tolerant and relatively xerophilous taxa chiefly dominated in wet bryophytes of poor Sphagnum-fens, while poor Sphagnum-fen bottom sediments could provide a refuge for less tolerant and hydrophilous species. In contrast to testate amoebae, monogonont rotifers preferred bryophytes in all sites, with the number of monogonont taxa distinctly increasing from calcareous fens to poor Sphagnum-fens. In poor Sphagnum-fens, monogononts were the most abundant in wet bryophytes, probably due to reduced food competition and/or predaceous pressure resulting from the limited occurrence of other groups of microorganisms by virtue of the hostile acidic conditions in wet Sphagnum carpets.

Fish biomass, species richness and composition were compared between upland streams draining two contrasting geological units (Pebas and Tsa) in Colombian Amazonia. Because Pebas sediments reportedly show higher levels of base concentrations than Tsa sediments, we expected that the fish communities from the Pebas streams would show highest biomass and species richness, and that the species composition would vary between the two upland systems. Eight forest streams were sampled in four locations, applying four daily sampling events. Tsa soil samples were comparatively sandy, whereas Pebas soil samples tended to be siltier, with higher levels of exchangeable acidity, Ca, Mg and total bases. Conductivity, concentrations of bases (Ca, Mg, K and Na), bicarbonates and temperature showed higher values in Pebas stream-water samples than in Tsa. In total, 7696 fish individuals were captured, belonging to eight orders, 28 families and 122 species. Pebas streams had 1.3 times more species than Tsa streams, and more than twice the total biomass. Species richness and biomass were highly correlated with conductivity and water concentrations of Mg and Na, and biomass alone with dissolved oxygen. Fish species composition differed significantly between the geological units. Species turnover was not related to distance between sampling locations.

The relationship between surface sediment diatom assemblages and measured limnological variables in 33 coastal Antarctic lakes was examined by constructing a diatom-water chemistry dataset. Canonical correspondence analysis revealed that salinity and silicate each explain significant amounts of variation in the distribution and abundance of the surface sediment diatom taxa. Salinity has the strongest influence, revealing its value for limnological inference models in this coastal Antarctic region.

Melt waters cover c. 20% of the McMurdo Ice Shelf during the austral summer. The streams, ponds, and lakes up to 104 m2 in area occur in two types of terrain systems with differing morphological, chemical, and biological characteristics: pinnacled ice (PI) areas with sparse sediment cover, low relief, and little biomass; and ice-cored moraine (ICM) areas with 10–20 cm sediment cover, hummocky topography with up to 20 m relief, occasional mirabilite deposits, and dense benthic cyanobacterial mats. Pond water composition in the two areas is markedly different. PI area melt waters have low salinities, <2270 mg 1−1 total dissolved salts (TDS), and near neutral pH, mean = 7.8. The chemical composition of PI waters closely follows that of diluted sea water, suggesting that the release of ions from the sea ice matrix of the ice shelf is the major solute source. In contrast, ICM area melt waters have a wide range of salinities, up to 60 400 mg 1−1 TDS and alkaline pH, mean = 9.3. The chemical composition in c. 40% of the ICM ponds investigated did not resemble that of sea water, but had higher relative abundances of SO2−4, Na+, K+ and Ca2+. Leaching of local salt deposits, particularly mirabilite, weathering of surficial sediments, and morphological features promoting closed-basin brine evolution are possible contributing factors to the enrichments.

The limnology and sedimentary diatom flora of fourteen lakes and ponds from the Windmill Islands, East Antarctica, is presented. Saline lakes, saline ponds and freshwater ponds are represented in this dataset. The Windmill Island lake diatom flora represents an intermediate floral assemblage between that of the freshwater lakes of the Larsemann Hills and the saline lakes of Vestfold Hills, East Antarctica. Variations within this assemblage are related to water chemistry variables in the Windmill Island lakes. In particular, a lakewater salinity/phosphate gradient can explain the variation observed in the sedimentary diatom flora of the lakes and ponds included in this study.

Concentrations of a wide range of chemical variables were determined in 206 water samples taken between May 1996 and May 1998 from a set of 25 natural lakes in the French Massif Central. From each lake 6 to 9 samples were collected. Mean and standard deviation of total alkalinity, conductivity, pH, concentrations in K+ , Mg2+ , Ca2+ , Na+ , Cl-, SO2 4 , total phosphorus, nitrate-nitrogen, dissolved silica, chlorophyll a, and water colour were calculated for each lake. These results are briefly compared with those obtained in an earlier study in which chemical analyses were carried out on a reduced set of lakes from the same region. In most lakes and for most elements, concentrations observed in the present study were similar to those observed previously. The seasonal variations of the elements which are most strongly influenced by biological processes were also investigated. Using hierarchical cluster analysis three main lake groups were distinguished : i) alkaline lakes, ii) deep lakes with lowalkalinity and iii) shallow lakes with low alkalinity. The major patterns of variation in the data set were also investigated using principal components analysis (PCA), which confirms that total alkalinity and maximum water depth are the main environmental gradients in this set of lakes. In conclusion, the potential of this data-set for building diatom-based transfer functions to reconstruct past limnological conditions is discussed.

Water chemistry and macroinvertebrates of four high mountain lakes (alt. 1657-1784 m) were investigated. The lakes areultraoligotrophic with naturally slightly acidic water. In three lakes these water level changed substantially during the year while in one it remained constant. Moreover, trophic status was higher in one than in the other three. Oligochaeta and Chironomidae dominated the invertebrate fauna of all lakes. Benthic faunal composition depended mainly on ecological factors such as substrate, trophic status, and hydroperiod. It appears that anthropogenic acidification has so far not affected faunal composition.

To study the relationships between groups of organisms and the degree to which these relationships are consistent across major climatic gradients, we analysed the testate amoeba (Protozoa) communities, vegetation and water chemistry of one peatland in five countries: Switzerland, The Netherlands, Great Britain, Sweden and Finland, as part of the BERI (Bog Ecosystem Research Initiative) project. The relationships between the different data sets and subsets were investigated by means of detrended correspondence analysis, canonical correspondence analysis and Mantel permutation tests. The comparison of data on vegetation and testate amoebae showed that inter-site differences are more pronounced for the vegetation than for the testate amoebae species assemblage. Testate amoebae are a useful tool in multi-site studies and in environmental monitoring of peatlands because: (1) the number of species in Sphagnum-dominated peatlands is much higher than for mosses or vascular plants; (2) most peatland species are cosmopolitan in their distributions and therefore less affected than plants by biogeographical distribution patterns, thus differences in testate amoeba assemblages can be interpreted primarily in terms of ecology; (3) they are closely related to the ecological characteristics of the exact spot where they live, therefore they can be used to analyse small-scale gradients that play a major role in the functioning of peatland ecosystems. This study revealed the existence of small-scale vertical gradients within the vegetation and life-form niche separation in response to water chemistry. The deep-rooted plants such as Carex spp. and Eriophorum spp. are related to the chemistry of water sampled at or near the ground water table, whereas the mosses are not. Testate amoebae were shown to be ecologically more closely related to the chemistry of water sampled at or near the water table level and to the mosses than to the deep-rooted plants.

Les proliférations de macrophytes atteignent désormais les eaux courantes et entraînent de nombreuses nuisances. La compréhension de ce phénomène nécessite une étude approfondie des peuplements végétaux en place et des paramètres d'environnement qui les conditionnent, afin de déterminer les phytocénoses de référence et leurs séquences de dégradation. Lors de cette étude, vingt et un cours d'eau, situés en tête de bassin versant et représentatifs de la diversité géologique de la Lorraine, ont été prospectés. Le choix des stations d'étude a été réalisé en fonction d'un découpage abiotique, définissant des zones de cours d'eau homogènes au niveau de la géologie, la pente et la largeur. La pertinence de l'utilisation de la géologie (classes de perméabilité) comme premier critère hiérarchique de classification des cours d'eau est confirmée par les résultats de cette étude. Les analyses chimiques et les relevés morphométriques effectués sur chaque station d'étude ont conduit à individualiser quatre grands types de cours d'eau (sur granites, sur grès, sur calcaires et sur marnes), dont la végétation aquatique a été inventoriée. Des successions végétales typiques en fonction de la position amont-aval ont été observées. Les notions de milieux naturellement fragiles et d'espèces « à risque de prolifération » ont été affinées. Cette étude constitue la base d'une typologie des cours d'eau par la végétation aquatique.

The Viséan sequence at East Kirkton was deposited in a shallow lake, set within a richly vegetated landscape formed of volcanic cones a few hundred metres high. There was little volcanic activity, however, while the lake existed, and the many tuff horizons within the sequence were washed in during weathering. The lake may have been generally cool, though of unusual water chemistry, as a result of which the spherulitic East Kirkton Limestone precipitated. At times, however, water temperatures may have risen sharply through localised hot-spring activity; both factors deterred ‘normal’ aquatic life.

The bulk of the preserved biota consists of plants (permineralisations and compressions) and dominantly land-living animals, including the oldest terrestrial tetrapods (amphibians and reptiliomorphs), large terrestrial-aquatic eurypterids, the first harvestman and rare millipedes. All these animals lived close to the lake, in a fire-prone forest dominated by gymnosperms and pteridosperms.

At a late stage in the history of the lake, deposition of spherulitic limestones was replaced by black shales, bearing a ‘standard’ Oil-Shale fish fauna, suggesting that the isolated lake had linked with a larger fish-bearing water body. This is coupled with a shift to a lycopod-dominated flora and may indicate a climatic change to wetter conditions. Finally the lake silted up with tuff, ending an existence of only a few tens of thousands of years.