The introduced fish, rotan (Perccottus glenii), depresses populations of aquatic animals (macroinvertebrates, amphibians, and a fish)

The fish rotan (Perccottus gleniiDybowski) was accidentally introduced into European Russia from the Amur River basin. Rotan is capable of colonising small waterbodies – favourable breeding sites of native amphibians. To reveal its influence on the native aquatic fauna, monitoring of small waterbodies has been carried out since 1994 in the region of Lake Glubokoe Reserve (Moscow Province, Russia). The fish's diet includes a wide range of animal species of all trophic levels. Rotan considerably decreases the species richness of aquatic macroinvertebrates and larval amphibians. As a rule, most amphibian species (Triturus cristatus, T. vulgaris, Rana temporaria, R. arvalis, R. lessonae) and the fish Carassius carassius failed to breed successfully in ponds inhabited by rotan. In contrast, the toad Bufo bufo bred successfully in such sites because its larvae are distasteful to rotan. Rotan–amphibian interactions are discussed.     

Cyanobacterial blooms and water quality in Greek waterbodies

The cyanobacterial species composition of nine Greek waterbodies of different type and trophic status was examined during the warm period of the year (May–October). Cyanobacterial water blooms were observed in all waterbodies. Forty-six cyanobacterial taxa were identified, 11 of which are known to be toxic. Eighteen species are reported for the first time in these waterbodies, 8 of which are known to produce toxins. Toxin producing species were found in all of the waterbodies and were primarily dominant in bloom formations (e.g., Microcystis aeruginosa, Anabaena flos-aquae, Aphanizomenon flos-aquae and Cylindrospermopsis raciborskii). Cosmopolitan species (e.g., M. aeruginosa), pantropic (e.g., Anabaenopsis tanganyikae) and holarctic species (e.g., Anabaena flos-aquae) were encountered. Shallow, eutrophic waterbodies had blooms dominated by Microcystis species and were characterized by phytoplankton association M. Anabaena and Aphanizomenon species of association H were dominant in waterbodies with low dissolved inorganic nitrogen and thermal stratification in the summer. Total cyanobacterial biovolumes (CBV) ranged from 7 to 9,507 cm³ m⁻³ and were higher than Alert Level 2 and Guidance Level 2 (10 cm³ m⁻³; World Health Organization; WHO) in seven of the waterbodies. Chlorophyll a concentrations ranged from 6 to 90,000 mg m⁻³ and were higher than Alert Level 2 and Guidance Level 2 (50 mg m⁻³; WHO) in eight of the waterbodies. There is also an elevated risk of acute toxicosis (Guidance Level 3; WHO) in five waterbodies. Water of an undesirable quality, hazardous to humans and animals occurs in several Greek waterbodies.     

Distribution and quantitative characteristics of common species of pond snails of the subgenera <Emphasis Type="Italic">Peregriana</Emphasis> and <Emphasis Type="Italic">Radix</Emphasis> (Mollusca: Gastropoda: Lymnaeidae) in waterbodies of the south of Western Siberia

Information on some ecological features of eight species of pond snails belonging to the subgenera Peregriana and Radix (Lymnaea ampla (Hartmann), L. ampullacea (Rossmässler), L. auricularia (L.), L. balthica (L.), L. fontinalis (Studer), L. lagotis (Schrank), L. ovata (Draparnaud), and L. tumida (Held)) in the waterbodies of south of Western Siberia is presented. The patterns of the species distribution and their cooccurrence in different waterbodies have been studied. An analysis of the quantitative variables (abundance and biomass) of the snails in the waterbodies of the Karasuk lake-river system and in the Novosibirsk Reservoir has been performed.     

Relationships of hydrology and life-history strategies on the spatio-temporal habitat utilisation of fish in European temperate river floodplains

Floodplain inundation is considered as crucial for the recruitment of fish in lowland rivers, by either providing suitable spawning areas as well as breeding habitats for young-of-the-year fish (YOY), as well as for supporting species that exhibit different life history-strategies in order to be differently adapted to long term discharge patterns. Fish communities in a set of 38 waterbodies on the Lower Rhine floodplain, representing different long-term frequencies of inundation and differently affected by seasonal inundations, were sampled by means of electro fishing (point abundance sampling, total n = 42,701 points) over a four-year period in order to identify species-specific and life-history strategy related patterns of spatio-temporal floodplain habitat utilisation. For 18 species (total catch: n = 107,150), typically occurring in European lowland rivers and representing different ecological guilds, different responses towards seasonal inundations were found. YOY of most species closely associated to the periodic strategy (e.g., Abramis brama, Aspius aspius, Blicca bjoerkna) were highly abundant in frequently inundated waterbodies, provided these were subject to inundations occurring in spring and early summer and coincided with temperatures required for spawning. However, recruitment in these species was impaired or failed when no inundations in this time frame occurred, although adults were present. In contrast, most species associated to the opportunistic strategy (e.g., Gasterosteus aculeatus, Pseudorasbora parva, Leucaspius delineatus) had highest recruitment in waterbodies unaffected by inundations in this time frame, which had detrimental effects on these predominantly small sized species. Spatio-temporal floodplain habitat utilisation of YOY fish (most rheophilic species as well as eurytopics) is suggested to be size-related, since most fast growing periodic strategists left the floodplain at given connectivity at latest in winter and were then absent in the subsequent year. Smaller YOY fishes and all opportunistic species either remained in more isolated waterbodies, or dispersed from there across the floodplain to some degree during extensive winter floods. These findings suggest adaptations to the long-term hydrograph of large river systems, with flood-related recruitment patterns predominantly occurring in periodic strategists and low-flow recruitment strategies in opportunistic strategists and stagnophilic species. The results of this study point to the significance of hydrological transversal floodplain gradients that provide diverse communities and population maintenance of different life-history strategies, evidencing that fish communities within the floodplain act as indicators for the hydrological conditions.     

Threshold Concentrations of Cations in the Water Necessary for Maintaining the Ionic Balance Between Organism of <Emphasis Type="Italic">Chironomus balatonicus</Emphasis> Devai et al. Larvae and Environment

Threshold concentrations of sodium, potassium, calcium, and magnesium in water determining the borders of the Chironomus balatonicus range in waterbodies are 0.6–0.62, 0.11–0.12, 0.071–0.073, and 0.022–0.028 mmol/L, respectively. In the freshwater section of the Curonian Lagoon of the Baltic Sea and other waterbodies with weakly mineralized water where the content of ions is lower than the threshold values, larval Ch. balatonicus cannot dwell because of the impossibility of maintaining the ionic balance between the organism and environment. The threshold concentrations and rates of loss of ions from an organism in various species of aquatic organisms are comparatively analyzed.     

Zooplankton in Lake Sevan during the period of high water level and low fish density

It is shown that, upon the flooding of ephemeral waterbodies in the coastal region and the formation of new warmer sites of the shoals due to the rising water level in Lake Sevan in 2011, species typical for temporary waterbodies and various shoals have been recorded in the zooplankton. Among them, Daphnia (Ctenodaphnia) magna Straus reached mass development, which was favored by the minimal control from “the top” and favorable trophic conditions. Owing to the abovementioned factors, the total lake zooplankton biomass and water transparency increased. The uneven distribution of D. (C.) magna was determined by the density of fish that prefer it as food.     

Zooplankton crustaceans of ephemeral waterbodies on the territory of various natural zones in Saratov oblast

The zooplankton of ephemeral waterbodies of Saratov oblast is represented by 68 species of crustaceans: 9 fairy shrimps, 25 cladocerans, 10 calanoids, and 24 cyclopoids. Regional and local patterns of high species diversity in the zooplankton of ephemeral waterbodies are discussed. The specificity of crustacean species composition in ephemeral waterbodies of intrazonal forest-steppe landscapes of the valley river basin of the Don River and of the steppes and desert steppes of Zavolzhye is shown. The number of crustacean species in the zooplankton increases from the northwest to southeast in all ephemeral waterbodies of forest-steppe (33 species), steppe (39), and desert steppe (52) zones. The impact of irrigation systems on the formation of zooplankton species composition in ephemeral waterbodies was established.     

Ten-year survey of cyanobacterial blooms in Ohio’s waterbodies using satellite remote sensing

Cyanobacterial blooms are on the rise globally and are capable of adversely impacting human, animal, and ecosystem health. Blooms dominated by cyanobacteria species capable of toxin-production are commonly observed in eutrophic freshwater. The presence of cyanobacterial blooms in selected Ohio lakes, such as Lake Erie and Grand Lake St. Marys, has been well studied, but much less is known about the geographic distribution of these blooms across all of Ohio’s waterbodies. We examined the geographic distribution of cyanobacterial blooms in Ohio’s waterbodies from 2002 to 2011, using a nested semi-empirical algorithm and remotely sensed data from the Medium Resolution Imaging Spectrometer (MERIS) onboard the European Space Agency’s Envisat. We identified: 62 lakes, reservoirs, and ponds; 7 rivers; 6 marshes and wetlands; and 3 quarries with detectable cyanobacteria pigment (phycocyanin) concentrations. Of the 78 waterbodies identified in our study, roughly half (54%; n = 42) have any reported in situ microcystins monitoring results from state monitoring programs. Further, 90% of the waterbodies identified reached phycocyanin pigment concentrations representative of levels potentially hazardous to public health. This gap in lakes potentially impacted by cyanobacterial blooms and those that are currently monitored presents an important area of concern for public health, as well as ecosystem health, where unknown human and animal exposures to cyanotoxins may occur in many of Ohio’s waterbodies. Our approach may be replicated in other regions around the globe with potential cyanobacterial bloom presence, in order to assess the intensity, geographic distribution, and temporal pattern of blooms in lakes not currently monitored for the presence of cyanobacterial blooms.     

Are cladoceran diversity and community structure linked to spatial heterogeneity in urban landscapes and pond environments?

Biodiversity patterns in cladoceran communities were investigated in urban waterbodies in relation with residential land use, pond management, and waterbody environments. We evaluated species richness in the pelagic and littoral zones of eighteen waterbodies of a large Canadian city. Gamma diversity (26 species) observed at a small scale in the urban survey was important comparatively to large-scale surveys of lakes. Beta diversity ranged from 1 to 8 species among waterbodies. We tested if littoral species greatly contributed to regional diversity in urban waterbodies. Littoral species (Chydoridae, Ilyocryptidae, Macrothricidae, Polyphemidae) accounted for 58% of the total species pool. We distinguished five cladoceran assemblages associated to different waterbodies (temporary ponds, permanent lakes, and wetlands). Cladoceran communities were more diverse and variable in permanent lakes than in temporary ponds. Changes in cladoceran species assemblages among waterbodies were driven by variations in waterbody size and phosphorus enrichment, macrophyte and algal biomass, urban density, pond management practices, and the presence of potential predators as fish and macroinvertebrates. Our study indicates that both artificial ponds and lakes and natural wetlands are valuable habitats for the conservation of cladoceran biodiversity and rare endemic species in urban regions. Further research on pond management strategies promoting urban aquatic biodiversity should be undertaken.     

Rapid colonization of a newly created habitat by cladocerans and the initial build-up of a Daphnia-dominated community

As part of a detailed study on the colonization of newly created and isolated pools by cladocerans, the community build-up of a pool near the Belgian coast was studied. Three large daphniid species managed to colonize this new habitat during the first year of its existence. The first colonizing species was Daphnia atkinsoni, a species very rare to the cladoceran fauna of Northwestern Europe and new to the Belgian fauna. Although the occurrence of Daphnia atkinsoni is striking, the colonization of the new habitat can be explained by short-range dispersal of resting eggs, as all three cladoceran species are present in waterbodies in the immediate proximity (0.5 km) of the new pool. It is hypothesized that the occurrence of Daphnia atkinsoni in the region is related to long-range dispersal of resting eggs associated with wintering geese, which are very abundant in the specific region. %     

Environmental variables associated with the distribution and occupancy of habitat specialist tadpoles in naturally acidic,oligotrophic waterbodies

Environmental factors play an integral role, either directly or indirectly, in structuring faunal assemblages. Water chemistry, predation, hydroperiod and competition influence tadpole assemblages within waterbodies. We surveyed aquatic predators, habitat refugia, water height and water chemistry variables (pH, salinity and turbidity) at 37 waterbodies over an intensive 22‐day field survey to determine which environmental factors influence the relative abundance and occupancy of two habitat specialist anuran tadpole species in naturally acidic, oligotrophic waterbodies within eastern Australian wallum communities. The majority of tadpoles found were of Litoria olongburensis (wallum sedge frog) and Crinia tinnula (wallum froglet) species, both habitat specialists that are associated with wallum waterbodies and listed as Vulnerable under the IUCN Red List. Tadpoles of two other species (Litoria fallax (eastern sedge frog), and Litoria cooloolensis (cooloola sedge frog)) were recorded from two waterbodies. Tadpoles of Litoria gracilenta (graceful treefrog) were recorded from one waterbody. Relative abundance and occupancy of L. olongburensis tadpoles were associated with pH and water depth. Additionally, L. olongburensis tadpole relative abundance was negatively associated with turbidity. Waterbody occupancy by C. tinnula tadpoles was negatively associated with predatory fish and water depth and positively associated with turbidity. Variables associated with relative abundance of C. tinnula tadpoles were inconclusive and further survey work is required to identify these environmental factors. Our results show that the ecology of specialist and non‐specialist tadpole species associated with ‘unique’ (e.g. wallum) waterbodies is complex and species specific, with specialist species likely dominating unique habitats.     

Austropotamobius pallipes reduction vs. Procambarus clarkii spreading: Management implications

One of the main threats to native European crayfish is the spread of alien crayfish species that are immune carriers of the detrimental crayfish plague Aphanomyces astaci. In this study we analyzed both at a regional and at a local scale factors determining native and alien crayfish distribution in an area where the species Procambarus clarkii is currently spreading. We aim to understand which management strategies could prevent the extinction of native populations. We sampled 81 waterbodies in Lombardy (NW Italy) to assess the Austropotamobius pallipes complex and alien crayfish occurrence; we also monitored the only first order stream in our study area that we found to be currently inhabited by A. pallipes upstream and by P. clarkii downstream. A. pallipes generally occurred in small brooks, near the spring, and was linked to low periphyton abundance, while P. clarkii occurred in sites at lower altitudes, far from the spring area, mainly in lentic waterbodies with large widths; this allochthonous species was positively related to periphyton abundance. Our monitoring showed that physical barriers such as dams may prevent P. clarkii dispersal upstream. Our results confirm that A. pallipes and P. clarkii have different ecological requirements and show that, at least during the first years of invasion, P. clarkii spreading involves lowland or downstream altered sites. We suggest the need for management strategies maximizing connectivity among native populations, to avoid isolation, and promoting the separation of native populations from those of P. clarkii.     

Macrozoobenthic Community and Assessment of Aquatic Ecosystem Health of three Waterbodies of East Calcutta Wetlands,India

The present study was aimed to understand the diversity, abundance and distribution of macrozoobenthic community of three selected fishponds differing in sewage intake and culture practices of East Calcutta Wetlands of Kolkata, India, as well as the aquatic ecosystem health of these waterbodies considering benthos as the best indicator of pollution. One year seasonal samplings were done to study the diversity and distribution of macrozoobenthos along with 12 water quality parameters to reflect the ecological conditions and aquatic ecosystem health of these waterbodies through biodiversity indices and statistical analysis (SPSS 10). A total of 27 species of macrozoobenthic organisms belonging to 18 families under four phyla comprising eight major groups viz. Polychaeta, Oligochaeta, Hirudinea, Diptera, Odonata, Gastropoda, Bivalvia and Pisces have been recorded. The diversity of macrozoobenthic fauna of these three waterbodies revealed that Ruby wetland had the highest representation of 24 species followed by Sukantanagar pond (17 species) and Sukantanagar bheri (16 species). The result of Pearson’s correlation coefficient showed that amongst the collected macrozoobenthos the gastropod species, Bellamya bengalensis and Lymnaea acuminata were wetland site-wise significant. The total benthic population and biomass have positive correlation with water transparency and organic enrichment of the waterbody. Shannon Weiner and Margalef’s indices have revealed higher values for Ruby wetland. Biodiversity indices and BMWP Score System designated to benthic organisms, suggested Ruby wetland is healthier than the other two waterbodies, differing in sewage intake and culture practices.     

Materials on the flora of Bacillariophyta in aquatic ecosystems of the Yarayakha River basin (Yamal Peninsula)

The study of phytoplankton in lakes, sors, streams, and rivers of the Yarayakha River basin with the help of scanning electron microscopy has made it possible to broaden the taxonomic spectrum of Bacillariophyta; 236 specific and intraspecific taxa from 63 genera are detected. A total of 16 species and varieties that are new for the flora of Russia were documented; 30 forms from 18 genera are identified only to the species. The maximum species diversity is recorded in a stream in the Yarayakha River mouth (82 species) and in the channel of the Khureikhotarka River (105 species). Species such as Cyclotella meneghiniana, Fragilaria exiguiformis, Navicula hanseatica, Neidium bisulcatum, Stauroneis anceps, Thalassiosira inserta, and Tabellaria flocculosa are the most widespread in the waterbodies.     

Parasite fauna of the perch fishes Percidae in waterbodies of the Kola Region

Results of the parasitological investigation of two species of perch fisches (perch Perca fluviatilis and ruff Gymnocephalus cernuus) from Kola Region are given. 63 species of parasites were found on perch in 16 waterbodies belonging to the White Sea and Barents Sea basins (Myxosporea--3, Pleurostomata--1, Suctoria--2, Peritricha--21, Protozoa incertae sedis--1, Monogenea--2, Cestoda--6, Trematoda--10, Nemadota--8, Acanthocephala--4, Hirudinea--1, Bivalvia--1, Crustacea--3). 33 species of parasites were found on ruff in 5 waterbodies belonging to the White Sea basin (Cyrtostomata--1, Hymenostomata--1, Peritricha--8, Monogenea--2, Cestoda--6, Trematoda--9, Nematoda--2, Acanthospehala--2, Bivalvia--1, Crustacea--1). Data on the infestation of perch and ruff by different parasite species are obtained, occurrence of the parasites in the examined waterbodies is shown.     

Morphology,production and mineral contents inPhragmites australis in different waterbodies of the Estonian SSR

The present work was carried out at four waterbodies in the Estonian SSR where seven different habitats ofPhragmites australis were selected. The paper gives the results of the study of clones from essentially different sites: the characteristics of the habitat of the species (soil profile, soil analyses, pH of water), morphological features of shoots, the nutrient content in plant parts, the production of clones, and also relations between these characteristics.     

New data on the flora of diatom algae (Centrophyceae) in waterbodies of Sakhalin Island

The first studies of phytoplankton in inland waterbodies of Sakhalin Island by electron microscopy have revealed 19 representatives of the class Centrophyceae, including some that are new for the flora of the region (Aulacoseira subarctica, Coscinodiscopsis commutata, Stephanodiscus delicatus, S. makarovae, Thalassiosira baltica, and T. cf. hyalina). Species of centric diatoms that are new for these waterbodies have been documented in lakes Vavaiskiye and Tunaicha, and the species composition of Centrophyceae have been revised. The first complete data on the taxonomical spectrum of Centrophyceae in Lake Sladkoye, lakes of Mount Spamberg, and the Tym River have been obtained. A revision of the species composition of Centrophyceae in the waterbodies of Sakhalin Island has been made, and the list of the class has been broadened to 44 taxa from 17 genera.     

Habitat selection and waterbody-complex use by wintering Gadwall and Shoveler in South West London: Implications for the designation and management of multi-site protected areas

The degree to which Special Protection Area (SPA) designation reflects ecological reality is of critical importance to wildlife conservation. We examined whether the designation of a large SPA designated to conserve wintering waterfowl (chiefly Gadwall Anas strepera and Northern Shoveler Anas clypeata), reflected the birds’ habitat preferences and their use of the SPA in the context of the broader geographic area. To do this, 67 discrete waterbodies in and around the South-West London Waterbodies Special Protection Area (SWL SPA) were surveyed regularly each winter from 2004/5 to 2006/7, and new analytical methods developed, to investigate habitat selection and multiple-site use by the birds. Significant pressure on these waterbodies for mineral extraction, development and recreation, together with a long history of human usage has resulted in a wide range of habitats and conditions for these wildfowl.We found that Gadwall and Shoveler were able to adjust their site preferences and patterns of site use in response to changes in food resources and other ecological variables both within and between winters. Akaike's Information Criterion (AIC) was used to model the distribution of wildfowl between sites using a large number of physical and ecological predictor variables. This showed that Gadwall and Shoveler differ in many of their habitat preferences, to the extent that managing a site for one will not necessarily directly benefit the other.At the time of this study the habitat preferences of Gadwall and Shoveler do not closely match the ecological condition of the SWL SPA waterbodies. Furthermore, an investigation into the use of multiple sites by Gadwall and Shoveler indicated that although there is evidence for populations of wintering birds using groups of waterbodies in the SW London area, their patterns of site use do not closely match the distribution of the seven separate SPA component waterbodies.We provide guidelines for managing habitats for Gadwall and Shoveler, and suggest that in addition to bird counts the SPA designation process for multi-site protected areas should consider the behaviour, habitat requirements and the influence of human disturbance on the species concerned. In this instance, the patterns of wildfowl site use present a reasoned argument for the inclusion of additional sites in the SW London Waterbodies SPA, or for dealing with the SPA in a different manner to a site with a more contiguous boundary.     

Old world versus new world: life-history alterations in a successful invader introduced across Europe

We examined differences in pumpkinseed (Lepomis gibbosus) life-history traits between native North American and introduced European populations, and tested three life-history predictions related to the effect of temperature, growth, waterbody size, and the presence/absence of predators on native and non-native populations. Pumpkinseed populations exhibit more ‘opportunistic’ traits (earlier maturity, smaller size at maturity, and higher reproductive allocation) in their introduced European range than those in their native range. Predictions of life-history traits were improved when indicators of juvenile growth rate (mean length at age 2), waterbody size (surface area), and thermal regime (air temperature degree-days above 10 °C) were incorporated into models along with continental location, but European pumpkinseed populations exhibit more opportunistic life-history traits than North American populations even when these factors are accounted for. Native pumpkinseed in waterbodies containing piscivores mature later and at a larger size, and have lower gonadosomatic indices than those in waterbodies lacking piscivores, whereas there is no significant difference in the same three life-history traits between European waterbodies containing or lacking piscivores. Because congeneric competitors of the pumpkinseed are absent from Europe, the apparent absence of a predator life-history effect there could also be due to the absence of the major sunfish competitors. In either case, the evolution and maintenance of more opportunistic traits in European pumpkinseed can likely be attributed to enemy release, and this may explain the successful establishment and spread of pumpkinseed in many parts of Europe.