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1.
We described the fish assemblage in the estuary of the Guaraguaçu River (one of the largest tributaries of the Paranaguá Bay Estuary, located within Brazil’s Atlantic Forest Biosphere Reserve) from June 2005 to May 2006, and assessed the seasonal and spatial effects of abiotic environmental attributes on the fish assemblage structure. Despite some oscillations in salinity, the upper and lower estuaries had year-round persistent oligohaline and polyhaline conditions, respectively. Despite high species richness (55 species), the Guaraguaçu River Estuary fish community contains a few dominant taxa; 11% of the richness accounts for >60% of its density and biomass. The most abundant species (in terms of both biomass and density) was Atherinella brasiliensis. Species whose densities were most strongly associated with the upper estuary were Centropomus parallelus, Ctenogobius schufeldti, Eucinostomus melanopterus, Platanichthys platana, Trinectes paulistanus, and Eugerres brasilianus. Those whose densities were most strongly associated with the lower estuary were A. brasiliensis, Sphoeroides greeleyi, Eucinostomus argenteus, Sphoeroides testudineus, Diapterus rhombeus, and Harengula clupeola. Throughout the year, canonical correspondence analysis identified: (1) the pattern of horizontal stratification of salinity along the river as being the most important variable for explaining most of the fish fauna structure; and (2) a strong relationship between the fish fauna and the salinity gradient along the estuary. Analysis of similarity further confirmed that each estuarine zone supports a year-round persistent and relatively homogeneous fish species assemblage. Total mean density and biomass remained constant over time in each estuarine habitat, but density shifted in the most abundant species, which appears related to recruitment patterns. Such species and abundance persistence likely occurs because seasonal rainfall-induced changes in river discharge are not sufficient to significantly shift runoff and salinity and thus fish assemblage structure (species composition, density and biomass) along the estuary. Such a lack of seasonal fish fauna movement as a response to changes in river flow contrasts with other estuarine systems around the world.  相似文献   

2.
The population of earthworms has been studied in the main types of old-growth dark coniferous forests of Pechora-Ilych Nature Reserve (Komi Republic) that have not been subject to anthropogeniс impact for a long time. Ten species of earthworms have been identified. The greatest diversity (7 species), abundance, and biomass of earthworms has been revealed in the tall-grass fir–spruce forests. P. diplotetratheca had the greatest abundance. E. nordenskioldi nordenskioldi and E. atlavinyteae had the greatest biomass. The lowest species diversity (3 species), abundance, and biomass of earthworms have been found in the largefern, blueberry–green moss, and sphagnum–horsetail fir–spruce forests. The role of deadwood in maintaining the species diversity of Lumbricidae in dark coniferous forests has been demonstrated. The complexes of Lumbricidae have been considered in anthropogenically disturbed territories, where the following species with a habitat range to the south of the northern and middle taiga have been identified: L. rubellus, A. rosea, A. caliginosa caliginosa, and E. fetida.  相似文献   

3.
Distribution of several widespread, extensively studied polymorphic variants of genes of the cytosol glutathione-S-transferase subfamily (GSTA1, GSTM1, GSTM3, GSTP1, and GSTT1) has been studied in samples from Russian populations of European Russia, as well as Komi and Yakut populations used for comparison. Analysis of the GSTP1 and GSTM3 polymorphisms has not revealed significant differences in the distribution of alleles of the loci, including two-site GSTP1 haplotypes, in most Russian populations and between Komi populations. Only in the Yakut sample have a significant difference been found with respect to these loci in each pairwise comparison. Regarding the GSTT1 and GSTA1 genes, in addition to differences between the Yakut population and all other populations with respect to the GSTA1 gene, it has been found that the frequencies of the GSTT1 0/0 deletion genotype and GSTA1 ?69T allele in the Russian sample from Mezen’ (Arkhangel’sk oblast) are substantially lower than in other Russian populations and Komi populations. The significance of these differences has been confirmed by tests for heterogeneity of the entire pool of Russian populations.  相似文献   

4.
The diatom assemblages of the surface sediments have been studied in 53 urban ponds and lakes of St. Petersburg for the first time. In total, 350 species and infraspecific taxa have been registered; the species of Achnanthidium, Cocconeis, Cyclostephanos, Cyclotella, Gomphonema, Lemnicola, Navicula, Nitzschia, and Stephanodiscus genera were the most common. The wide distribution of small centric planktonic taxa, Cyclostephanos dubius, C. invisitatus, Cyclotella pseudostelligera, Stephanodiscus hantzschii, and S. minutulus, is preconditioned by the depletion of dissolved silica, which is a result of the high phosphorus load. The high abundance of macrophytes in the shallowest sites favors the dominance of epiphytic Fragilaria, Staurosira, and Staurosirella taxa. Bottom-living diatoms in the shallow eutrophic and hypereutrophic urban ponds are light-limited; this is a result of either macrophytes or phytoplankton development. Alkaliphilous and alkalibiontic species prevail among the pH-indicative species, while eutraphentic and hypereutraphentic diatoms, as well as those thriving in a wide range of trophic conditions, dominate over other trophic groups. The β- and α-mesosaprobic species are the most common saprobity-indicative taxa.  相似文献   

5.
This paper provides an overview of the leaf-mining insect community feeding on willows (Salix spp.) and poplars (Populus spp.) in Siberia. According to published data and our own observations, 50 leaf-mining insect species (i.e., 24 species of Lepidoptera, 15 Coleoptera, 6 Diptera, and 5 Hymenoptera) feed on those two plant genera in Siberia. Using an integrative approach combining field work, morphological and DNA barcoding analyses, we identified 32 leaf-mining insect species from 14 regions across Siberia (i.e. 64% of all leaf-mining species known on Salicaceae in this part of Russia). Among them, 26 species most often found in parks and botanical gardens, represented new faunistic records for several poorly explored regions of Siberia. We have more than doubled the list of Salicaceae-feeding leaf-mining insects in Tomsk oblast, Altai krai, and the Republic of Tuva, and for the first time provided data on leaf-miners for the Khanty–Mansi Autonomous Okrug. The micromoth Phyllocnistis gracilistylella (Gracillariidae), recently described from Japan, was found on a new host plant (Salix caprea) in the south of Krasnoyarsk krai, is new for Russia. Eight leafmining insect species (i.e., five gracillariids: Phyllocnistis labyrinthella, Ph. unipunctella, Phyllonorycter apparella, Ph. sagitella, and Ph. populifoliella; two beetles: Zeugophora scutellaris and Isochnus sequensi; and one sawfly: Heterarthrus ochropoda) can outbreak on poplars, most often in urban plantations, botanical gardens, and plant nurseries in Siberia, and can also affect natural stands. Forty-five species of 50 leaf-mining insects known to feed on willow and poplar in Siberia also occur in Central and Eastern Europe. The remaining five species (Phyllocnistis gracilistylella, Phyllonorycter sibirica, Heterarthrus fasciatus, Tachyerges dauricus, and Isochnus arcticus) are recorded in Asia only. Species richness of the family Gracillariidae, the most diverse on Salicaceae in Siberia, displays 80% similarity to that in the European part of Russia and 71% to the Russian Far East. We discuss the faunal similarity of these regions and highlight the importance of applying an integrative approach combining ecological, morphological analyses, and DNA barcoding to explore and characterize the insect fauna of poorly studied regions of Asian part of Russia.  相似文献   

6.
Gobioid fishes collected in Nha Trang and Van Phong bays (Vietnam) represented by 44 species, including 30 species continuously associated with soft bottoms in the open parts of the bays with normal marine conditions are reviewed. A new species, Navigobius khanhoa sp. n., is described. This species differs from other species of the genus in much higher number of rays in the second dorsal fin (26), smaller size of the mouth, teeth on the jaws arranged in a single row, and other characters. Four species from the genera Acentrogobius, Eviota, Favonigobius, and Gnatholepis have not been identified to the species, and, most likely, some of them are new for science. Nine species are recorded in the fauna of Vietnam for the first time: Aulopareia unicolor, Bathygobius hongkongensis, Egglestonichthys bombylios, Glossogobius circumspectus, Oplopomops diacanthus, Oxyurichthys auchenolepis, Tomiyamichthys ex gr. russus, Tryssogobius porosus, and Valenciennea immaculata. An occurrence of Glossogobius olivaceus in the fauna of Vietnam is confirmed. Three species, G. olivaceus, Oligolepis acutipennis, and Periophthalmus kalolo, are recorded in the Cai River delta for the first time. A new synonymy is established: Eviota gurjanovae (Prokofiev, 2007) = E. prasina (Klunzinger, 1871). The current state of knowledge of Gobiidae fauna of Vietnam is discussed, and the updating of the species composition of Gobiodontini of Nha Trang Bay is presented in addition to the species list published earlier (Prokofiev, 2007).  相似文献   

7.
Cryptic species have been repeatedly described for two decades among the Antarctic fauna, challenging the classic model of Antarctic species with circumpolar distributions and leading to revisit the richness of the Antarctic fauna. No cryptic species had been so far recorded among Antarctic echinoids, which are, however, relatively well diversified in the Southern Ocean. The R/V Polarstern cruise PS81 (ANT XXIX/3) came across populations of Abatus bidens, a schizasterid so far known by few specimens that were found living in sympatry with the species Abatus cavernosus. The species A. cavernosus is reported to have a circum-Antarctic distribution, while A. bidens is only recorded with certainty in South Georgia and at the northern tip of the Antarctic Peninsula. Based on genetic and morphological analyses, our results clearly show that A. bidens and A. cavernosus are two distinct species. The analyzed specimens of A. bidens group together in two haplogroups separated from one another by 2.7 % of nucleotide differences. They are located in the Weddell Sea and in the Bransfield Strait. Specimens of A. cavernosus form one single haplogroup separated from haplogroups of A. bidens by 5 and 3.5 % of nucleotide differences, respectively. The species was collected in the Drake Passage and in the Bransfield Strait. Morphological analyses differentiate A. bidens from A. cavernosus. In contrast, the two genetic groups of A. bidens cannot be differentiated from one another based on morphology alone, suggesting that they may represent a case of cryptic species, common in many Antarctic taxa, but not yet reported in Antarctic echinoids. This needs to be confirmed by complementary analyses of independent genetic markers.  相似文献   

8.
The flea fauna of the Ciscaucasia comprises 76 species, 13 of which are associated with birds and the rest, with mammals. Rodent parasites are the most numerous; fleas associated with carnivores, bats, and insectivores are less abundant. Fleas parasitize different species of birds of the orders Passeriformes, Anseriformes, Falconiformes, and Strigiformes. Among 41 flea genera known from the Caucasus, species of the genera Amalaraeus, Araeopsylla, Atyphloceras, Caenopsylla, Callopsylla, Doratopsylla, Paraneopsylla, Peromyscopsylla, Phaenopsylla, Tarsopsylla, and Wagnerina are absent in the Ciscaucasia. Only two subendemic species were revealed in the region; 33 flea species are distributed over the entire Ciscaucasia, while the distribution of others is limited to landscapes of one or two natural zones.  相似文献   

9.
Although the area of Lake Yeniça?a is a potential candidate for RAMSAR convention, several anthropogenic factors compromise its biological diversity. This is mostly due to nutrient-rich water released from both point and nonpoint sources. Thirteen ostracod taxa (Candona neglecta, C. candida, Ilyocypris bradyi, Darwinula stevensoni, Cypridopsis vidua, Physocypria kraepelini, Cypria ophtalmica, Prionocypris zenkeri, Eucypris virens, Herpetocypris reptans, Pseudocandona compressa, Fabaeformiscandona fabaeformis Potamocypris cf. fulva) were found during this study. Potamocypris cf. fulva is a new record for the Turkish freshwater ostracod fauna. The first nine of these species have broad geographic ranges, implying high tolerance levels to different environmental variables. Based on the estimated species optima and tolerance levels, two species exhibited higher effective number of occurrences (C. neglecta, and D. stevensoni, respectively) than the other species. Three species (C. neglecta, D. stevensoni, I. bradyi) did not show significant correlation with any environmental variable we used. Both Canonical correspondence (CCA) and Pearson correlation analyses showed that temperature was the most effective predictor of species occurrence, followed by electrical conductivity and redox potential. In contrast, pH and dissolved oxygen of water were the least effective predictors. Approximately 71% of the correlation between community composition and environmental variables was explained by the first axis of the CCA diagram, which had a relatively low (7.7%) cumulative variance of species. The lower (560 μg/l) and the upper (2030 μg/l) levels of ammonia (NH3) exceeded the limits during winter season. The concentrations of total coliform and Escherichia coli bacteria were measured up to 10 × 107 cfu/ml and 10 × 103 cfu/ml, respectively. Results of physicochemical measurements, microbiological counts, and species data indicate that water quality of Lake Yeniça?a has been rapidly deteriorated by anthropogenic factors that are the main threat for not only the lake’s aquatic diversity but also human health around the lake.  相似文献   

10.
The genus Deporaus from the Russian fauna is revised. Four species (D. pacatus, D. azarovae, D. septentrionalis, and D. hartmanni) of the subgenera Pseudapoderites and Japonodeporaus are found. Keys to the subgenera and to the species of the subgenus Pseudapoderites are given. The genus Deporaus, subgenera Pseudapoderites and Japonodeporaus, and four species are redescribed. The distribution of these species in Russia is discussed.  相似文献   

11.
Prokaryotic diversity was studied in the planktonic communities of six Sol-Iletsk lakes (Orenburg oblast, Russia) varying in salinity level using the Illumina technology of high-throughput sequencing. The extremely halophilic archaea of the phyla Euryarchaeota and Nanohaloarchaeota, as well as the bacterial phylum Bacteroidetes predominated in the communities of lakes with salinity of 285–300‰. Representatives of the phyla Bacteroidetes and Actinobacteria, as well as of the class Gammaproteobacteria were predominant in the lakes with salinity 110?180‰. A bloom of Cyanobacteria was observed in Bol’shoe Gorodskoe Lake (10‰ salinity). The dominant OTUs in the lakes with high salinity were represented by archaea Halonotius sp., uncultured Nanohaloarchaea, and bacteria Salinibacter sp. In the lakes with medium salinity level the dominants included gammaproteobacteria Spiribacter sp., alphaproteobacteria Roseovarius sp., flavobacteria Psychroflexus sp., unidentified archaea of the family Haloferacaceae, actinobacteria Pontimonas sp. and Rhodoluna sp. In the lake with low salinity level cyanobacteria of the genus Planktothrix were predominant. Effect of salinity on prokaryotic taxonomic richness, composition, and diversity in planktonic communities of the studied lakes was demonstrated.  相似文献   

12.
The subgenera Roelofsideporaus and Deporaus s. str. of the genus Deporaus with four species (D. affectatus, D. unicolor, D. nidificus, and D. betulae) recorded from the Russian fauna are revised. Keys to the species of the subgenus Roelofsideporaus and to the females of the subgenera Roelofsideporaus and Deporaus s. str. are given. The distribution of D. nidificus in Russia is not confirmed.  相似文献   

13.
Recent advances in the taxonomy of cyanobacteria due to the utilization of molecular methods (such as 16S rRNA analysis) require a comparison of genetically identified items with their morphological expression. Morphological variability of seven monoclonal populations of the planktonic coccoid genus Chroococcus Nägeli, isolated mostly from reservoirs, fishponds, and littoral substrata from localities in the Czech and Slovak Republics, were studied experimentally under various combinations of nutrient concentration, light intensity, temperature, and water movement. Two cultivation media (WH-WC and BG11) commonly used in algal collections were applied in a liquid state. Of these, the WH medium was found to be more convenient for planktonic forms. Impacts of combined temperature and light gradients, concentration of P–PO4, and a stable versus shaken medium were found to stress different morphological modifications as a consequence of varied growth intensity and media convenience. Cell width was chosen as the parameter for testing changes in morphology; formation of mucilage and packets of cells were also taken into account. According to 16S rRNA gene analysis, the sequences of 10 strains (including seven studied in the experiments), which were assigned to the genus Chroococcus in the Culture Collection CCALA T?eboň (www.cas.ccala.cz) formed four distinct phylogenetic groups. While two of them showed no affiliation to the genus Chroococcus, two other groups proved the polyphyletic character of the genus. Apart from the group of typical species of the genus Chroococcus, a group of planktonic species could be distinguished, i.e., Chroococcus limneticus Lemmermann 1898 (Limnococcus), and was established as a new genus after recombination.  相似文献   

14.
The timely characterization of high-altitude freshwater habitats allows an assessment of the diversity of its biota and provides the basis for monitoring community change. In this study, we investigate the Cladocera fauna of 29 water bodies (pools, freshwater lakes, and surrounding swamps sampled at various occasions between 2005 and 2009) in the Rwenzori Mountains (Uganda, D. R. Congo), which are part of the East African Sky Island Complex. All sites except one are located above 3700 m altitude. We include notes on the morphology, taxonomy, distribution, and ecology of each recorded taxon and describe a new species of the Alona rustica-group (Alona sphagnophila n.sp.; Chydoridae). We found 11 species of which seven are restricted to Lake Mahoma, the lowest lake in our study area (2990 m) (Alona affinis barbata, A. intermedia, Alonella exisa, Alonella nana, Daphnia cf. obtusa, Pleuroxus aduncus) and/or Lake Bujuku (Daphnia cf. curvirostris, P. aduncus) (3900 m). Two taxa (Ilyocryptus cf. gouldeni, A. sphagnophila n.sp.) are restricted to Carex/Sphagnum bogs surrounding lakes in the afroalpine zone. Pigmented populations of Chydorus cf. sphaericus occur in all the sites. It is the only cladoceran species surviving the extreme alpine and nival conditions in the Rwenzori. The species is joined by A. guttata at locations at lower altitudes (ca. 3000–4000 m), present in about half of the sites. The Rwenzori Cladocera fauna is characterized by a strong extratropical temperate component and a low level of speciation/endemism. Harboring an impoverished boreal cladoceran community, Lake Mahoma is given closer attention. At 2990 m, the lake is a cold-temperate aquatic island in the tropics and may function as a stepping stone for Palaearctic taxa. We introduce a new term for high-altitude, cold-water habitats in the tropics, which act as climatic islands for extratropical freshwater faunas, Löffler Islands, in honor of Dr Heinz Löffler. In comparison to surveys in 1961, we list five new records in Lake Mahoma, which could indicate cladoceran community changes over the past few decades at ca. 3000 m in the Rwenzori. Since the species distributions correlate to temperature and catchment properties of the lakes, the Rwenzori cladoceran fauna can be expected as sensitive indicators for local changes.  相似文献   

15.
Industrial ethanol fermentation is subject to bacterial contamination that causes significant economic losses in ethanol fuel plants. Chronic contamination has been associated with biofilms that are normally more resistant to antimicrobials and cleaning efforts than planktonic cells. In this study, contaminant species of Lactobacillus isolated from biofilms (source of sessile cells) and wine (source of planktonic cells) from industrial and pilot-scale fermentations were compared regarding their ability to form biofilms and their sensitivity to different antimicrobials. Fifty lactobacilli were isolated and the most abundant species were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus plantarum. The majority of the isolates (87.8%) were able to produce biofilms in pure culture. The capability to form biofilms and sensitivity to virginiamycin, monensin and beta-acids from hops, showed inter- and intra-specific variability. In the pilot-scale fermentation, Lactobacillus brevis, L. casei and the majority of L. plantarum isolates were less sensitive to beta-acids than their counterparts from wine; L. brevis isolates from biofilms were also less sensitive to monensin when compared to the wine isolates. Biofilm formation and sensitivity to beta-acids showed a positive and negative correlation for L. casei and L. plantarum, respectively.  相似文献   

16.
The species composition of centrohelid heliozoa (Centrohelida) in saline and brackish inland water bodies and watercourses with salinity 2.0–42.2‰ was studied in the subarid zone of Russia. Nine species (Polyplacocystis ambigua, Pterocystis foliacea, Choanocystis ebelii, Acanthocystis astrakhanensis, A. dentata, A. myriospina, A. pectinata, A. taurica, A. turfacea) are new for saline and brackish inland waters. A. astrakhanensis and A. taurica are new for the fauna of Orenburg region. The first data on centrohelidian fauna in saline rivers of Elton region were obtained. The fauna comprises Polyplacocystis ambigua, Pterocystis foliacea, A. turfacea and Choanocystis ebelii. C. ebelii is new for the protist fauna of Russia. Five species (Polyplacocystis ambigua, Pterocystis foliacea, A. pectinata, A. dentata, A. taurica) were recorded for the first time in saline and brackish waters and described as eurihaline. Morphological diagnoses of Acanthocystis dentata and A. taurica were completed.  相似文献   

17.
The data on the fauna of blackflies of the tribe Simuliini (Diptera: Simuliidae) of the Sakha Republic (Yakutia) comprising the available literature, collections of the Zoological Institute of the Russian Academy of Sciences, and new material collected in Yakutia were analyzed. Three new species were recorded in the fauna of Yakutia: Archesimulium polare Rubzov, 1940, A. splendidum Rubzov, 1940, and A. tumulosum Rubzov, 1956. Distribution of 11 species was clarified. Processing of the collected material confirmed the presence of 9 blackfly species previously known from Yakutia. On the whole, the blackfly fauna of the region comprises 27 species.  相似文献   

18.
São Paulo is the most developed state in Brazil and little of its native vegetation remains. In Luiz Antonio and Santa Rita do Passa Quatro municipalities, only small fragments of cerrado (Brazilian savanna) physiognomies (cerradão, cerrado sensu stricto) and of semideciduous forest have been left, surrounded by eucalyptus silviculture and sugar-cane agriculture. However, that vegetation mosaic still shelters large mammals, including several carnivore species. To detect the carnivores present in such a mosaic area (50,000 ha), and to find out how they use the landscape, we recorded them through 21 camera traps and 21 track plots, during 18 months. Species richness, diversity and relative frequency were evaluated according to the habitat. Ten species were recorded, some of them locally threatened to extinction (Puma concolor, Leopardus pardalis, Chrysocyon brachyurus). Species diversity did not significantly differ among fragments, and although most species preferred one or another habitat, the carnivore community as a whole explored all the study area regardless of the vegetation cover; eucalyptus plantations were as used by the carnivores as the native fragments. Therefore, it seems possible to maintain such animals in agricultural landscapes, where some large native fragments are left and the matrix is permeable to native fauna.  相似文献   

19.
A parasitological study was performed of chars of the genus Salvelinus inhabiting Lake Kronotskoe (Kamchatka Peninsula)—S. malma, S. albus, S. schmidtii, and S. kronocius, as well as of juvenile Salvelinus spp. Twenty-three species of parasites, including six species new for the lake, Hennequya zschokkei, Protteocephalus longicollis, Diphyllobothrium dendriticum, Crepidostomum sp., Echinorhynchus salmonis, and Paracanthobdella livanowi, were found. With consideration of published data, in chars of this water body, 28 species of parasites were recorded, including seven species (N. cf. pungitius, B. luciopercae, Crepidostomum sp., Cr. fausti, Cr. cf. cooperi, Eubothrium crassium, and Proteocephalus sp.), whose presence or species identification in the lake ecosystem need confirmation. Two species (N. rutili and Diphyllobothrium sp.) are removed from the list. Parasites common for all species of chars were revealed. They include Myxobolus arcticus, E. salvelini, D. ditretum, Crepidostotum sp., Cr. farionis, Cr. metoecus, Cystidicola farionis, Cucullanus truttae, Philonema oncorhynchi, and Salmincola carpionis. Cluster analysis of the fauna of parasites of different species of chars demonstrated considerable differences in infestation, which indicates differences between them in preference for food items and occupied biotopes and thereby supports the ecological differentiation of chars in the basin of Lake Kronotskoe. S. albus and S. kronocius are most similar in parasitofauna, which is determined by their predation; S. malma as a benthophage is infected by the same species of parasites, but considerably less intensively. Extremely high indices of population numbers of some parasite species are considered as a manifestation of the Krebs cycle in parasites under the conditions of an isolated lake.  相似文献   

20.
A sediment record of cladoceran remains was analysed in a 543 cm long core from Ple?né jezero (Ple?né Lake), the Bohemian Forest, Czech Republic. The core covered the time period from the Oldest Dryas to the present. Littoral and benthic Cladocera included 11 species of the family Chydoridae while three species (Bosmina longispina, Daphnia cf. pulicaria and D. cf. longispina) lived in the open water. Remains of Alona quadrangularis and Chydrous sphaericus occurred in the oldest sediment layers from the beginning of the Bølling chronozone. Bosmina longispina and Daphnia cf. pulicaria appeared about 400 years later. Inorganic sediment accumulated at a relatively high rate of ~ 90 mg cm?2 yr?1 at that time, diluting cladoceran remains and organic matter. Remains of Cladocera accumulated at 0.1 to 0.01 of the Holocene rate, making it difficult to observe effects of climate variation on the species structure of Cladocera in the Late-Glacial. Production of remains increased after warming during the Younger Dryas-Preboreal transition at ~11.6 kyr BP, and the proportion of littoral species increased. The most important change in cladoceran fauna occurred at ~10.5 kyr BP and culminated with afforestation of the catchment around 10.3 kyr BP. The domaination of Bosmina longispina lasted for ~250 years. The afforestation occurred concurrently with a decrease in lake water pH. Bosmina longispina and Daphnia cf. pulicaria disappeared, production of cladoceran remains decreased, but biodiversity increased. Planktonic Cladocera were represented by Daphnia cf. longispina during most of the rest of the Holocene. The production of Cladocera never reached the Preboreal level. Since ~ 5 cal. kyr BP, the inferred pH continuously decreased. The final decline was likely caused by cooling during the Little Ice Age and by sulphur emissions from ore smelting. The recent acidification of lake water and impoverishment of aquatic fauna was brought about by emissions of sulphur and nitrogen compounds in the 20th century.  相似文献   

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