Stony Substrate Research Articles

Сравнительная оценка методов определения педогенного органического углерода в углесодержащих почвах

The research considered determination of carbon reserves of soil organic substances in coal-bearing soils as an important problem of the study of technogenic landscape soils of coal deposits. Basing on the ability of soils of technogenic landscapes to perform the functions of natural undisturbed soils, the total fund of soil organic substance in such soils is said to be formed not only by humic compounds, but also by oxidized carbonaceous particles. Therefore, only developing the methods for differentiating soil organic substance performing the function of humus, and non-transformed lithogenic organic substance can solve the problem of evaluating the state of coal-bearing soils. The aim of the work is a comparative evaluation of the possibility of using traditional approaches and two those which we propose to determine the content of pedogenic organic carbon in soils of coal deposit dumps. Embryosems formed on the surface of coal and brown coal deposit dumps in Kemerovo oblast (N 53 o 39'; E 86 o 53') and Krasnoyarsk Krai (N 55 o 58'; E 90 o 23') were objects of the research. Methodically, along with traditional methods based on the content of total and organic carbon determination, we use approaches that rely on functional characteristics of soil organic substance. The first approach is based on the ability of soil organic substances to deposit nitrogen in soils. This approach involves calculation of carbon content of pedogenic organic substances using the parameters of soil nitrogen reserves and its ratio with carbon (C / N) in zonal undisturbed soils. The second approach is based on the ability of soil organic substance to form organic and mineral complexes with clay particles. At the same time, the content of pedogenic carbon is determined by the value of lithogenic potential of humus accumulation (LPHA), which depends on the number of clay particles in soils. Our research has shown that for carbon-containing soils, methods based on determination of total and organic carbon give incorrect results and cannot be used in complex ecological studies of techogenic soils and landscapes. Approbation of the proposed approaches has shown that, the definition of LPHA makes it possible to obtain reliable results for embryozems formed on a dense, stony substrate of coal deposits (See Table 2), since the accumulation of clay particles in such soils is the result of biochemical weathering and their amount is proportional to the reserves of organic substance. For embriozems formed on a loose substrate of brown coal deposit dumps, the results obtained with the help of C / N ratio and nitrogen content in the investigated soils are the most representative (See Table 2). Thus, we can conclude that, even in this approximation, the proposed approaches allow carrying out large-scale studies on evaluating the ecological state and resource potential of coal-bearing soils of technogenic landscapes. The article contains 2 Tables, 39 References.

The effect of bloom of filamentous green algae on the reproduction of yellowfin sculpin Cottocomephorus grewingkii (Dybowski, 1874) (Cottoidae) during ecological crisis in Lake Baikal.

In shallow water areas of open Lake Baikal, filamentous green alga of the genus Spirogyra grows abundantly. Together with alga of the genus Ulothrix, it forms algal mats. According to our observations from 2010 to 2013, the spawning habitat conditions for the yellowfin sculpin Cottocomephorus grewingkii (Dybowski, 1874) (Cottidae) proved to be significantly disturbed in the littoral zone of Listvennichnyi Bay (southern Baikal), which, in turn, reduced the number of egg layings. With a 100% projective cover of the floor and a high density of green filamentous algae, the shallow-water stony substrate becomes completely inaccessible for spawning of the August population.

Distribution and habitats of <i>Burnupia mooiensis</i> in South Africa: (Walker 1912 [Gastropoda: Ancylidae

Burnupia mooiensis was already described in 1912 from specimens from the Mooi River, Potchefstroom while the oldest sample in the National Freshwater Snail Collection (NFSC) dates back to 1956. There are currently 14 species on record; however, to date the geographical distribution and habitat requirements of only two species were published. The geographical distribution of the 224 samples of B. mooiensis on record in the database of the NFSC and certain aspects of their sampling sites were analysed and the frequency of occurrence in different waterbodies, water conditions and substrata presented in tables. Data was statistically treated to determine habitat requirements. The largest percentage of samples came from rivers (57.59%), streams (18.30%) and the majority was collected in perennial habitats with stony substrata. Burnupia mooiensis is distributed mainly in the south-eastern areas of North-West, central areas of Gauteng and the south-western areas of Mpumalanga. In contrast to this, the distribution of B. capensis and B. stenochorias covers a much wider area, in spite of the fact that all three were already described by 1912 from sites in South Africa and that they share similar habitat requirements. The 14 species of Burnupia are spread over 556 different loci (0.0625°<sup>2</sup>) and therefore is one of the most widespread freshwater snail genera in South Africa. In view of its wide distribution, largely sessile, benthic lifestyle and the fact that they feed on epilithon, it is recommended that the feasibility to utilise them as bio-indicators of heavy metal pollution in waterbodies in different areas of South Africa be confirmed.

Vegetation composition and structure of some Neotropical mountain grasslands in Brazil

The description and understanding of plant communities is fundamental for the implementation of conservation or restoration programs, especially when these communities are highly threatened and need to be restored. Campos rupestres, some Neotropical mountain grasslands located in central Brazil and part of the Cerrado biome (covering 2 million km²) host unique plant communities, currently threatened by quarrying and mining. The grassy matrix of campos rupestres, has long been considered a rich mosaic under the control of local topography and the nature of substrate, but this affirmation has not been well studied. We analyzed whether plant communities varied in relation to edaphic factors within the stony substrate and the sandy substrate of this grassy matrix. We selected 5 sites where occur both grasslands on stony substrate and on sandy substrate, and we carried out vegetation surveys and soil analyses. We counted 222 plant species within our communities, among which 38.6% are exclusively found on campos rupestres. Our results show that both soil-types are strongly acidic, nutrient poor and exhibit a seasonal variation. Phosphorus increases and pH and organic carbon decrease during the dry season. Stony soils are slightlyricher in nutrients than sandy soils and differences in soil granulometry and composition have led to the formation of distinct plant communities. Some species are confined to either one or the other grassland-type, which makes the plant composition of each community unique.Variations in edaphic factors generate heterogeneous grasslands favorable to a high plant diversity. Conservation programs and restoration actions have to maintain or recreate this heterogeneity. The presence of distinct plant communities implies that different strategies might be adopted to improve the restoration of these ecosystems.

Substratum preferences of the invasive killer shrimp Dikerogammarus villosus

AbstractThe ability to select appropriate substratum in a patchy environment is crucial for food availability, reproductive success, anti‐predator defence and resistance to other environmental dangers. Therefore, even euryecious invasive species may exhibit clear substratum preferences, contributing to their success in novel areas. We used 24‐h pairwise‐choice experiments to study substratum preferences of the highly invasive freshwater Ponto‐Caspian gammarid Dikerogammarus villosus (Amphipoda, Crustacea). We tested its preferences for stony substrata of various grain diameters (2–124 mm), macrophytes differing in structural complexity (Myriophyllum spicatum, Ceratophyllum demersum, Potamogeton perfoliatus, Potamogeton nodosus, Stuckenia pectinata) and zebra mussels. We hypothesized that: (1) gammarids would select substrata adjusted to their body size and offering maximum protection; (2) mussels would be the most preferred substratum except in high densities, which lead to deterioration of water quality; (3) large gammarids would displace smaller conspecifics to worse substratum. Our results showed that large (>9 mm) and small (<7 mm) gammarids preferred stones >6 cm and between 6 and 8 cm, respectively, with relatively large empty spaces among particles (4–9 cm). Small gammarids selected complex plants, particularly M. spicatum, whereas large individuals also preferred less complex forms with large leaves (Pot. nodosus, Pot. perfoliatus). Small gammarids exhibited higher affinity for natural macrophytes than large individuals. All gammarids preferred stones over plants. Contrary to most of the published data, gammarids selected stones more often than dense zebra mussel colonies and did not discriminate between low density mussel and stone habitats. Oxygen depletion seems to be the factor distracting gammarids from mussel habitats. Thus, they seem to select mussel colonies only when alternative hard substrata are missing. Differences in substratum preferences between size classes were not pronounced, but small individuals switched to the less preferred habitat in the presence of adults, probably avoiding cannibalism and competition.

Cryptic diversity of caddisflies in the Balkans: the curious case of Ecclisopteryx species (Trichoptera: Limnephilidae)

Adults and larvae of two new cryptic, endemic caddisflies, Ecclisopteryx keroveci sp.n. and Ecclisopteryx ivkae sp.n., are described and illustrated from the Western Balkans. Phylogenetic analysis (Bayesian MCMCMC) and association of different life history stages in both cryptic species were achieved through comparison of morphological characters and mitochondrial (mtCOI and mtLSU) and nuclear (nuWG) gene sequence data. The new species form a sister clade to the widely distributed E. dalecarlica and E. guttulata, with which they were formerly misidentified. Adults differ from each other and other species in the genus by the uniquely shaped inferior appendages in males and segment X in females. The larvae differ from each other and their congeners in the shape of the pronotum, and presence and constitution of additional spines on the parietalia. Larvae of both species are grazers and prefer stony substrate. Ecclisopteryx keroveci sp.n. has a wide distribution in the Western Balkans, while E. ivkae sp.n. is endemic to Dalmatia. Our findings demonstrate the significance of the Western Balkans as a freshwater biodiversity hotspot, and accentuate the importance of research focused on freshwater biodiversity and biogeography in southern Europe.

HYDROBIOLOGICKÁ STUDIE ŘÍČKY BOBRAVY

The qualitative and quantitative composition of macrozoobenthos in the Bobrava rivulet was summarized utilizing former and recent studies. Altogether, 187 taxa of macrozoobenthos were determined in the Bobrava rivulet and its tributaries until now. The highest values of macrozoobenthos were found on the stony substrate with mean values of biomass and density corresponding to 18.7 g . m−2 and 2922 ind . m−2, respectively. Lower values were determined on the muddy and sandy substrates with 12.4 g . m−2 and 1587 ind . m−2, and 4.2 g . m−2 and 531 ind . m−2, respectively. The index of saprobity upstream the town Rosice corresponded to oligo-betamesosaprobity. Downstream the towns of Rosice, Omice and Radostice on the middle course of the Bobrava rivulet, water duality declined to beta – to alphamesosaprobity. Due to the self-purification ability of the stream, its water quality was improved to beta-mesosaprobity bellow the municipal pollution sources in the river stretch between localities Závist and Želešice.

ROČNÍ CYKLUS ZOOBENTOSU STŘEDNÍHO ÚSEKU ŘEKY DYJE

The qualitative and quantitative composition of the macrozoobenthos in the middle course of the Dyje River downstream the Znojmo reservoir was carried out in the years 2007 to 2008. Altogether, 118 taxa of macrozoobenthos were determined in the section between localities Tasovice and Dyjákovice. The highest values of macrozoobenthos were found on the stony substrate with mean values of biomass and density corresponding to 25.4 g . m−2 and 6 033 ind . m−2, respectively. Lower va­lues were determined on the sandy substrates with 5.8 g . m−2 and 5 857 ind . m−2, respectively. The index of saprobity on the locality Tasovice corresponded to betamesosaprobity (Si = 1.70), for the lo­ca­li­ty Dyjákovice the same index was (Si = 1.80).

Correlative evidence for competition between Fucus serratus and the introduced chlorophyte Codium fragile subsp. fragile on the southwest coast of Norway

Abstract The distribution of Codium fragile subsp. fragile and the native canopy-forming alga Fucus serratus was recorded at 51 sites in a 20 km long, sheltered region on the southwest coast of Norway. The purpose of the study was to examine if these species are potentially competing and how their distributions are related to wave-exposure and substrate. Codium fragile subsp. fragile was patchily distributed, a pattern which appears to have been sustained over time since its introduction to this area. It was almost always observed growing below mean low water, in the low intertidal and shallow subtidal. Both substrate type and wave-exposure influenced the vertical distribution of C. fragile subsp. fragile; growth occurred higher on the shore at sheltered sites and deeper in the subtidal on stony substrate. Its vertical range of growth overlapped with that of F. serratus and, when C. fragile subsp. fragile was abundant, F. serratus tended to grow higher on the shore and at lower abundances. This suggests that C. fragile subsp. fragile is affecting F. serratus in this area through competition, but only in the lower portion of the fucoid’s vertical range and only at sites favorable for its own growth with regard to shelter and substrate.

Restoration of Neotropical grasslands degraded by quarrying using hay transfer

AbstractAimThe campos rupestres are species‐rich tropical mountain grasslands in southeast Brazil that are threatened by mining and quarrying. Eight years following a strong disturbance (i.e. quarrying for gravel exploitation during the asphalting of highway MG‐010), spontaneous succession did not occur on degraded areas. This study was therefore designed to test the restoration technique of hay transfer as a means of enhancing seed dispersal from the reference ecosystems to the degraded areas.LocationCampo rupestre grasslands, Serra do Cipó, Minas Gerais, Brazil.MethodsNine degraded areas representing three kinds of substrate (latosol, sandy and stony) were selected. Hay transfer was carried out using hay collected in two kinds of grassland (i.e. campos arenosos and campos pedregosos) year‐round in 2010, in order to maximize the seed pool. The collected hay was distributed on 40 cm × 40 cm quadrats among the three types of substrate, with and without geotextile, according to the following protocol: hay from campo arenoso grasslands was spread on all types of substrate, while hay from campo pedregoso grasslands was used on stony substrate only.ResultsFew seedlings emerged within 14 mo of the treatment application, despite the large number of seeds contained in the hay, indicating that hay transfer may not be a useful method for restoring degraded areas of campos rupestres. The seedlings emerging on the degraded areas mainly belonged to ruderal species. Therefore, we suggest that, although poor soil conditions could limit seedling establishment, germination issues of the campo rupestre species are the first limitation for restoring degraded campos rupestres using hay transfer.ConclusionOur results highlight the inherent difficulty in restoring degraded areas of campos rupestres; their protection must be made a high conservation priority.

The River Gelså restoration revisited: Habitat specific assemblages and persistence of the macroinvertebrate community over an 11-year period

The study was undertaken on the River Gelså, Denmark, where a 1.8km meandering course was established in 1989 to replace a channelized river reach. This restoration project was the first of its kind in Denmark and has the longest time-series of post-intervention data of any restoration project conducted world-wide. Additionally, a 0.5km upstream (control) reach that remained channelized has been sampled since 1989. In this paper, we examined macroinvertebrate assemblages in distinct habitats in 2008, 19 years after the restoration, and community persistence between two years, 1997 and 2008, to investigate the longer-term effects of restoration on the biota. We found that habitat type influenced macroinvertebrate community composition to some degree, while there were no clear effects on α- and β-diversity of habitat or reach type. Stony substrate habitats introduced as part of the restoration could, however, still be separated from other habitat types and were much more frequent in the restored reach. Furthermore, very little change had occurred over the 11-year period from 1997 to 2008, suggesting a high degree of community persistence. Our results suggest that the local species pool was already close to saturation in 1997 and that only limited immigration of new species occurred in the intervening period until 2008. The lack of long term benefits could be attributed to the simultaneous cessation of weed cutting (which had almost as big a positive impact as restoration), other types of stress on the river (eutrophication) and dispersal limitations. However, it might also reflect that River Gelså is still functionally channelized and is far from exhibiting a dynamic river morphology governed by natural processes that create a range of habitats for the biota and this might explain why there has not been a more pronounced increase in macroinvertebrate diversity in River Gelså.

Population and distribution changes of two coexisting river amphipods after the closure of a new large dam

This study examined short-term changes of population size and distribution of two coexisting river amphipods after a major disturbance event – the closure of a new large dam on the Gojačka Dobra River (Central Croatia) in June 2010. In the pre-disturbance period, coexistence of the two species, the endemic moss specialist Echinogammarus cari and the widespread microhabitat generalist Gammarus fossarum , was promoted by differential microdistribution between two dominating types of microhabitats, moss and stony substrate. E. cari was dominant in mosses and G. fossarum on stony substrate, representing an excellent case of spatial niche partitioning between two species of river amphipods. Drastic change in water quality and increased load of suspended particles that accumulated in mosses soon after the dam closure were the main factors that contributed to E. cari rapid population decline at sites downstream of the new dam. G. fossarum was much less affected by such changes, exhibiting no drastic population decline and even an increase in population size after disturbance event at three examined sites. Hence, specialization of E. cari for moss microhabitats which enabled stable coexistence of the two species before damming made it more vulnerable to disturbance and resulted in dominance shift in moss microhabitats in favour of G. fossarum after dam closure. This shift might reduce the probability of E. cari population recovery downstream from the new dam and change its current conservation status from endangered to critically endangered if it completely disappears downstream of the dam. Urgent measures aimed at conservation of this endemic species are proposed and discussed.

Water Quality and Ecological State Assessment of the Blagoevgradska Bistritsa River (South-West Bulgaria) Based on Macrozoobenthos Collected by Two Sampling Standards

ABSTRACTComplex investigations of the Blagoevgradska Bistritsa River, left tributary of the trans-boundary Struma River, were carried out in the summer of 2008. Seven representative sites were sampled. Physico-chemical parameters such as water temperature, pH, oxygen concentration, oxygen saturation, conductivity, nitrates and phosphates were measured. The biological assessment was based on macroinvertebrate communities—one of the obligatory biological quality elements according to the Water Framework Directive requirements and the national legislation. Canonical Correlation Analysis (CCA) was used for the explanation of the site-physico-chemical factors relationship. Indices of species diversity (c, e, H), saprobiological index (SR), biotic index (BI) and trophic index (RETI/PETI) were used to determine the water quality and the ecological state of the water bodies.According to the values of the physico-chemical parameters, indices of species diversity and the saprobiological index, the water quality of the sites from the source to the city of Blagoevgrad was I—II category. The ecological state was assessed as high, according to BI and high and good, based on the trophic index RETI. The water quality at the Blagoevgradska Bistritsa mouth, influenced by the waste waters of the city of Blagoevgrad, was assessed as II—III category, and the ecological condition, as moderate and poor (BI) and bad (PETI). The distribution of the physico-chemical parameters at the ordination diagram divided the studied sites into two groups: upstream (clean, unaffected sites) and downstream (anthropogenically influenced sites) of the city of Blagoevgrad.Two periods of investigation (2002–2003 and 2008) and two standard methods for macrozoobenthos sampling (handnet sampling of aquatic benthic macroinvertebrates and quantitative samplers for benthic macroinvertebrates on stony substrata in shallow freshwater) were compared. The results showed that for a five-year period of time changes in the water quality and the ecological state of the studied sites had not been observed. The two sampling methods gave similar results as regards the values of the indices used.

山地河流浅滩深潭生境大型底栖动物群落比较研究——以重庆开县东河为例

浅滩和深潭是山地河流中常见的河流生境结构。2011年7月,在重庆开县东河上游双河口-杉木桥河段,选择21个浅滩和深潭,调查大型底栖动物,研究影响不同生境中底栖动物组成、分布和多样性的生态机理。结果表明:调查河段浅滩和深潭中大型底栖动物分别为31种和24种,密度分别为450.62 个/m²和86.24 个/m²,生物量分别为2.88 g/m²和0.55 g/m²。浅滩有指示种11种,即纹石蛾(<em>Hydropsyche </em>sp.)、假蜉(<em>Iron </em>sp.)、假二翅蜉(<em>Pseudocloeon </em>sp.)、舌石蛾(<em>Glossosoma </em>sp.)、高翔蜉(<em>Epeorus </em>sp.1)、背刺蜉(<em>Notacanthurus</em> sp.)、<em>Heterocloeon</em> sp、锯形蜉(<em>Serratella</em> sp.)、朝大蚊(<em>Antocha </em>sp.)、等蜉(<em>Isonychia</em> sp.)、溪颏蜉(<em>Rhithrogena </em>sp.)。深潭指示种仅蜉蝣(<em>Ephemera </em>sp.)和黑大蚊(<em>Hexatoma </em>sp.)两种。刮食者为两类生境的优势功能摄食类群。浅滩中滤食者和刮食者比例显著高于深潭,而收集者和捕食者显著低于深潭。两类生境中大型底栖动物群落结构差异显著。浅滩中大型底栖动物的密度、生物量、丰富度指数、Shannon-Wiener 指数、改进的Shannon-Wiener指数均明显高于深潭。受地貌形态、水力特征和冲淤变化规律影响的生境稳定性和异质性差异是导致大型底栖动物群落差异的主要原因。;Riffle and pool, which exhibit very different physical characteristics (such as depth, velocity, substrate), are basic and common habitat units in mountain rivers. The benthic macroinvertebrate is an important connector among the different trophic levels of stream ecosystem and its community could be easily affected by variation of physical characteristics of microhabitat. However, previous researches did not always demonstrate a clear difference of community structure and diversity between riffle and pool macroinvertebrate. Dong River is a typical mountain stream which is located in a karst area of southwestern China, namely Kaixian County of Chongqing. In order to study variations in structure, composition and diversity between riffle and pool macroinvertebrate assemblage, we chose twenty one pairs of riffles and pools to investigate benthic macroinvertebrate species in upstream of Dong River in July 2011. Our results indicated that the difference of water quality was not significant between the two habitats. However, the riffle habitat not only had a wider water surface and faster flow velocity, but also contained bigger substrate than those of the pool habitat. The number of species was thirty one in riffles and twenty four in pools. Density and wet biomass of macroinvertebrate assemblage in riffles were 450.62 ind/m²and 2.88 g/m², respectively, comparing to 86.24 ind/m²and 0.55 g/m²in pools. Mayfly was the group with the highest density, abundance and species richness in both habitats. Virtually all species were more abundant in riffles than those in pools, except chironomids, <em>Ephemera </em>sp and <em>Hexatoma </em>sp which were more abundant in pools. Indicator Species Analysis indicated that a greater number of taxa, including <em>Hydropsyche </em>sp, <em>Iron </em>sp, <em>Pseudocloeon </em>sp, <em>Glossosoma </em>sp, <em>Epeorus </em>sp2, <em>Notacanthurus</em> sp, <em>Heterocloeon</em> sp,<em> Serratella</em> sp,<em> Antocha </em>sp,<em> Isonychia</em> sp and <em>Rhithrogena </em>sp, were restricted to riffles, while only two species, <em>Ephemera </em>sp and <em>Hexatoma </em>sp, were indicator species of pools. Kruskal-Wallis Test indicated that relative abundance of each functional feeding group was significantly different between the two habitats. Scraper was the dominant functional feeding group in both habitats, while shredder had the lowest relative abundance. Relative abundance of functional feeding groups between riffle and pool were significantly different except that of shredder. Riffles exhibited significantly higher percentage of collector-filterer and scraper, while percentage of collector-gatherer and predator in pools were significantly higher than that of riffles. Detrended Correspondence Analysis indicated that the difference of macroinvertebrate community structure was obvious between the two habitats. Density, wet biomass, species richness, Shannon-Wiener index and Improved Shannon-Wiener index of riffles were significantly higher than those of pools, which was similar with former researches conducted in mountain stream with stony substrate. Pool characterized by small and loose substrate is unstable and vulnerable habitat for benthic macroinvertebrate to resist fast flow during the flooding period. However, bigger substrate of riffle as a result of erosion creates a much more diverse and stable for macroinvertebrate to escape predators and disturbance of scouring. Therefore, habitat stability and heterogeneity affected by habitat morphology, hydraulic characteristics and erosion/deposition pattern may be the major explanation.

Dispersal of invasive species by drifting

Abstract Drifting can be an effective way for aquatic organisms to disperse and colonise new areas. Increasing connectivity between European large rivers facilitates invasion by drifting aquatic macroinvertebrates. The present study shows that high abundances of invasive species drift in the headstream of the river Rhine. Dikerogammarus villosus and Chelicorophium curvispinum represented up to 90% of the total of drifting macroinvertebrates. Drift activity shows seasonal and diel patterns. Most species started drifting in spring and were most abundant in the water column during the summer period. Drift activity was very low during the winter period. Diel patterns were apparent; most species, including D. villosus, drifted during the night. Drifting macroinvertebrates colonised stony substrate directly from the water column. D. villosus generally colonised the substrate at night, while higher numbers of C. curvispinum colonised the substrate during the day. It is very likely that drifting functions as a dispersal mechanism for crustacean invaders. Once waterways are connected, these species are no longer necessarily dependent on dispersal vectors other than drift for extending their distribution range.

Macrophyte development in unimpacted lowland rivers in Poland

Freshwater classification according to the Water Framework Directive (WFD) is based on estimation of the deviation between biological elements found on river stretch in comparison with communities detected in the same river type under reference conditions (undisturbed and near-natural habitats). We present analyses to describe macrophyte development in pristine lowland rivers and to reveal the variation among various stream types. The study is based on a country-wide survey of Poland with a dataset of 642 sites on 367 water courses. Surveyed rivers covered the whole lowland area of Poland. Field surveys were conducted using the Polish macrophyte approach, which enabled calculation of several macrophyte metrics. Firstly, a numerical index MIR (Macrophyte Index for Rivers) was computed, which reflects river degradation, especially eutrophication. Furthermore, five diversity metrics were calculated. Each survey, in addition to macrophyte assessment, was supplemented by a complex suite of environmental records. Reference conditions were defined using four criteria: (1) catchment land use, (2) hydromorphological features, (3) water quality and (4) biological assessment. The selected reference lowland rivers included 40 sites. To classify plant data, two-way indicator species analysis Twinspan was used. This resulted in distinguishing four end-clusters which were heterogeneous according to plant composition: organic rivers and three types of siliceous rivers (small with sandy substrate, small with stony substrate and large rivers). The differentiation of environmental factors between river types was confirmed by a variance analysis (ANOVA). Furthermore, the environmental database was explored with principal component analysis (PCA). The PCA principal components were analysed against river types with the canonical correspondence analysis (CCA). Finally botanical differences between identified river types have been detected, using botanical metrics the share of different macrophyte groups and relationships with particular species were defined.

Combining data-driven methods and lab studies to analyse the ecology of Dikerogammarus villosus

The spread of aquatic invasive species is a worldwide problem. In the aquatic environment, especially exotic Crustacea are affecting biodiversity. The amphipod Dikerogammarus villosus is such an exotic species in Flanders, which is rapidly spreading and probably has a serious impact on aquatic communities. The purpose of the present study was to make use of lab results, field data and modelling techniques to investigate the potential impact of this species on other macroinvertebrates. All types of prey that were used in predator–prey experiments ( Gammarus pulex, Gammarus tigrinus, Crangonyx pseudogracilis, Asellus aquaticus, Cloeon dipterum and Chironomus species) were consumed by D. villosus, especially species that were less mobile such as the Chironomus species. The presence of gravel somewhat reduced predation by providing shelter to the prey. Substrate preference experiments indicated that D. villosus preferred a stony substrate. Using decisions trees to construct habitat suitability models based on field observations, it could be concluded that D. villosus is mainly found in habitats with an artificial bank structure, a high oxygen saturation and a low conductivity, which corresponds with canals with a good chemical water quality. Moreover, a synecological classification tree, based on the abundance of the taxa present in the macroinvertebrate communities, indicated that the presence of D. villosus negatively affected the presence of the indigenous G. pulex. When the laboratory experiments and the field observations are combined, it can be concluded that D. villosus can seriously affect macroinvertebrate communities in Flanders.

A new genus and species of Leptophlebiidae (Ephemeroptera) from northern New Zealand

A new species of Leptophlebiidae is described from the far north of New Zealand and a new genus Aupouriella is erected to contain it. The new genus is unique among New Zealand Ephemeroptera in that eyes of adult males are not divided into upper and lower portions. The penes terminate in a prominent ventrally–projecting spine partially enclosing the sperm groove, and the posterior margin of the styliger plate has a prominent, upwardly curved projection, medially. Nymphs, subimagos and adults of Aupouriella pohei n. sp. have very slender legs, and are easily recognised by their bold abdominal markings. Nymphs were found on stony substrata in a small coastal stream at the type locality near North Cape along with nymphs of at least five other leptophlebiid species.

The river before damming: distribution and ecological notes on the endemic species Echinogammarus cari (Amphipoda: Gammaridae) in the Dobra River and its tributaries, Croatia

The endemic species Echinogammarus cari (Karaman 1931) is the only species of this genus present in the Black Sea drainage basin of Croatia. The species is known only from its type locality, the Bistrac spring. Since little is known about the distribution and ecology of this amphipod species, research was conducted to determine the extent of its distribution in the Dobra River and its tributaries, part of which will be flooded on the completion of a 52.5 m high dam in 2009. Sampling was conducted at 10 study sites in the drainage area of the sinking Gornja Dobra and at 19 study sites in the Gojacka Dobra, including measurement of physicochemical parameters. To examine microdistribution of this species, samples were collected on moss and on stony substrate. The species is confined to first 15 km of the Gojacka Dobra, its tributary streams Bistrica and Ribnjak, while it is absent in the drainage area of the Gornja Dobra. At all sites where it was recorded, it coexists with Gammarus fossarum, and its relative abundance was significantly higher on moss microhabitats, while G. fossarum was more abundant on a stony substrate. The downstream decrease in the relative abundance of E. cari could be related to the longitudinal decrease in conductivity and the increase of water temperature fluctuations. After the completion of the dam, 60% of the presently known distribution area of E. cari will be flooded. Consequently, the species is likely to become endangered.

Mapping benthic habitat in regions of gradational substrata: An automated approach utilising geophysical, geological, and biological relationships

The relationship between acoustic backscatter, sediment characteristics and benthic habitat is examined using high-resolution sidescan sonar data collected at the Loch Linnhe artificial reef site on the west coast of Scotland. The site is typical for the continental shelf of NW Europe, with a mix of seabed environments from muddy to coarse, stony substrata on a 10–100 m length scale. A sidescan sonar mosaic was produced and classified according to derived backscatter parameters (mean, median and standard deviation of the backscatter values) using an unsupervised classification procedure. The accuracy of the final classified map was assessed by comparison with a ground-truthing survey in which the biological habitat was derived from underwater video footage. The sidescan correctly predicted seabed surface characteristics of observed biological habitat with 78% accuracy. A second, and more challenging test of the acoustic data to correctly predict biological habitat was made by comparing it with data from 21 grab sampling stations. These stations were divided into three groups using multivariate statistical techniques based on their backscatter properties. Benthic assemblage structure was found to be significantly distinct between the high and low, and the medium and low backscatter stations. There was a low to moderate but significant correlation between the multivariate patterns of acoustic backscatter, benthic assemblage structure, and particle size distribution. The work shows that even in areas with subtle and gradational changes in substratum, the sidescan was able to predict biological community with an acceptable accuracy.