Number Of Dominant Species Research Articles

Insecticide applications to soil contribute to the development of Burkholderia mediating insecticide resistance in stinkbugs.

Some soil Burkholderia strains are capable of degrading the organophosphorus insecticide, fenitrothion, and establish symbiosis with stinkbugs, making the host insects fenitrothion-resistant. However, the ecology of the symbiotic degrading Burkholderia adapting to fenitrothion in the free-living environment is unknown. We hypothesized that fenitrothion applications affect the dynamics of fenitrothion-degrading Burkholderia, thereby controlling the transmission of symbiotic degrading Burkholderia from the soil to stinkbugs. We investigated changes in the density and diversity of culturable Burkholderia (i.e. symbiotic and nonsymbiotic fenitrothion degraders and nondegraders) in fenitrothion-treated soil using microcosms. During the incubation with five applications of pesticide, the density of the degraders increased from less than the detection limit to around 10(6)/g of soil. The number of dominant species among the degraders declined with the increasing density of degraders; eventually, one species predominated. This process can be explained according to the competitive exclusion principle using V(max) and K(m) values for fenitrothion metabolism by the degraders. We performed a phylogenetic analysis of representative strains isolated from the microcosms and evaluated their ability to establish symbiosis with the stinkbug Riptortus pedestris. The strains that established symbiosis with R. pedestris were assigned to a cluster including symbionts commonly isolated from stinkbugs. The strains outside the cluster could not necessarily associate with the host. The degraders in the cluster predominated during the initial phase of degrader dynamics in the soil. Therefore, only a few applications of fenitrothion could allow symbiotic degraders to associate with their hosts and may cause the emergence of symbiont-mediated insecticide resistance.

Identification of potentially invasive species of black flies [Diptera: Simuliidae] from Armenia based on an analysis of variability in the mtDNA barcode of the cox1 gene and chromosomal polymorphism

Black flies (Diptera, Simuliidae) are well known for their medical, environmental, and veterinary importance. The simuliid fauna of Armenia includes 53 species. A number of dominant species are of ecological importance. Complex analysis, which involved morphometric, cytogenetic, and molecular genetic approaches, was conducted to characterize the species status of black flies inhabiting the territory of Armenia. It was shown that the predominant simuliid species, Simulium paraequinum and Simulium kiritshenkoi, belong to a group of species with minimal variability of the cox1 gene. The recently discovered species, Simulium noellery and Simulium [B.] erythrocephalum, which are new to Armenia, can be considered as potentially invasive, which is supported by the low level of variability of the cox1 gene.

Weed infestation of soybean (Glycine max L. Merr.) under different tillage systems

Direct drilling is one of the methods to reduce tillage costs. Low labor intensity of this system also makes it possible to grow crops in locations where it is a problem to maintain optimal sowing time. However, the use of no-tillage can cause increased weed infestation of crop plants and as a consequence a decline in crop yields. The present study investigated the effect of two tillage systems, plough tillage and direct drilling, on the species composition, density and air-dry weight of weeds in crops of two soybean cultivars (‘Aldana’ and ‘Augusta’). A three-year field experiment was set up on loess-derived gray-brown podzolic soil. The study showed that the use of direct drilling for soybean cropping resulted in a significant increase in the density and dry weight of weeds relative to plough tillage. The study also found richer floristic composition of weeds and an increase in the numbers of dominant species under no-tillage conditions. <em>Elymus repens</em>, <em>Echinochloa crus-galli</em> and <em>Chenopodium album</em> were dominant weed species in all experimental treatments. <em>Chenopodium album</em> and <em>Galinsoga parviflora</em> were characterized by the highest constancy (constancy classes V and IV) in crops of both soybean cultivars, whereas <em>Echinochloa crus-galli</em> showed the highest constancy value in the ‘Aldana’ crop. Under direct drilling, most weed species were found to exhibit higher constancy compared to plough tillage.

Effect of different treatment on endophytic bacterial communities in continuous cropping of Chrysanthemum morifoliu

To reveal the effect of rotation cropping and bacterial manure on the growth of Chrysanthemum morifolium and screen the beneficial endophytic, the diversity of endophytic and dominant genera of different treatment groups were analyzed. Four different treatments were continuous cropping, rotation, self-made organic fertilizer and commercially available fertilizer, respectively. Endophytic bacterial diversity and dominant genera in different organs were examined using Terminal Restriction Fragment Length Polymorphism (T-RFLP). The results showed that enzyme Hae III was more appropriate than enzyme Hinfl because the number of TRFs digested by enzyme Hae III was more than that of enzyme Hinfl. In comparison of diversity, the endophytic bacterial communities' diversity index in group of cropping rotation and fertilizer was higher than that of continuous cropping which indicated that the addition of exogenous microorganism in soil could increase the diversity of plant endophyte. 18 dominant species were selected, including 3 kinds of Firmicutes, 4 kinds of Actinomycetes and 11 kinds of Proteobacteria. The results of dominant species comparison showed that the number of dominant species in continuous cropping of Ch. morifolium was significantly less than that of the rotation group. Some dominant bacteria in rotation group and fertilizer group such as Arthrobacter, Streptomyces, Streptomyces, Flavobacterium and Mycobacterium were not found in the continuous cropping of Ch. mortfolium group. Dominant species of fertilizer treatment group was similar with the rotation group, and the continuous cropping group's dominant species was more abundant. It indicates that these bacteria may be able to mitigate hindrance in continuous cropping, especially the Flavobacterium which can decompose the pathogenic fungi is worthy of further attention. Compared with leaves, there are more dominant species in roots and stems. The diversity of edophytic bacterial communities in continuous cropping of Ch. morifolium stays below than that in the rotation of Ch. morifolium, and fertilizer treatment can increase the diversity of continuous cropping so that it could mitigate hindrance in continuous cropping.

Community characteristics and of zooplankton in Qinzhou Bay

Qinzhou Bay, the biggest bay in Guangxi Province, is very species-rich and is developing a robust marine economy. In recent years, as human impact has increased, problems associated with the environment have become more complicated. Measuring zooplankton diversity and abundance is a way to monitor environmental conditions. According to the data from four ecological surveys of the zooplankton in Qinzhou Bay during 2008 and 2009, a total of 134 species of zooplankton were identified, including 52 Copepoda species, 27 Medusa species, 14 Planktonic larvae, 9 Chaetognatha species, 8 Pteropoda species, 5 Amphipoda species, 4 Cladocera species, 4 Ostracoda species, 3 Thaliacea species, 2 Appendiculata species, 2 Sergestdae species, 2 Protlsta species, 1 Rotiera species and 1 Cumacea species. The fauna was clearly characterized as tropical population. The total species number was highest in autumn, followed by spring, winter and summer. Zooplankton species diversity in Qinzhou Bay has increased compared with the results obtained in 1983–1985 (83 species). However, compared with other bays, the number of zooplankton species in Qinzhou Bay is close to Daya Bay (128), higher than in Zhilin Bay (60), Jiaozhou Bay (81) and Luoyuan Bay (70), and far lower than in the north South Sea (709). We adopted the dominant index Y>0.02 as the distinguishing standard of dominant species. The number of dominant species in spring, summer, autumn and winter were six, nine, eight and five. There was only one common dominant species (Penilia avirostris) appeared in different seasons, For summer and autumn, the shared dominant species numbered about four. Between other seasons, the shared dominant species varied between two and three. The number of uniquely dominant species was four in summer, three in autumn and one in both spring and winter. The dominant species in different seasons have some overlaps and some differences. The average biomass of zooplankton was 378mg/m3 at all times of year. The average biomass was largest in autumn, followed by winter, and was the least in spring and summer. The average density of zooplankton for the entire year was 805.11ind/m3. The average density was largest in summer, followed by winter, and was least in autumn and spring. Copepoda and Planktonic larvae were the major components of zooplankton in spring and summer at Qinzhou Bay, with the other species’ densities under 10%. In autumn, Copepoda, Planktonic larvae and Chaetognatha were the major components of the biomass, and in winter, the major species were Copepoda and Cladocera, with the others species’ density under 10%. The average value of the Shannon–Wiener diversity index (H′) was 3.84 and the evenness index (J′) was 0.77. The zooplankton diversity index and community evenness overall were good and the community organization had a complete and stable state, but the status of the community was relatively weak. The relationship between biomass/density of zooplankton and environmental factors is remarkable. Biomass and density are positively correlated with temperature and nutrient concentration, and are negatively correlated with salinity.

Species structure and year-to-year dynamics of nekton biomass in the upper epipelagic layer of the Pacific waters at Kuril Islands in summer periods of the 2000s

The North-West Pacific waters at Kuril Islands are characterized by high productivity because of high water dynamics due to interaction of the Kamchatka, Oyashio, and Kuroshio Currents and tidal mixing. Abundance, species composition, and spatial density of nekton in the upper epipelagic layer (0-50 m) of this area are considered on the data of trawl surveys conducted in June-July of 2004-2012. In total, 97 species of nekton are found in the trawl catches, including 73 species of fish and 24 species of cephalopods belonged to 15 genera and 8 families. Myctophidae have the highest species richness and biomass among fish (12 species, 33% of the total nekton biomass), and Gonatidae have the highest number of species and biomass among cephalopods (13 species, 11 %). Mesopelagic fishes, being temporary inhabitants of the epipelagic layer, dominate in the nekton community (54 species, 60 % of total biomass), they migrate to the upper layer at night for feeding. Other important ecological groups are salmons migrating to spawning grounds and subtropical species migrating to feeding grounds. Ratio between these groups is very variable. Total abundance of nekton varied from 1.1 t/km² in 2010 to 4.6 t/km² in 2004, on average 2.4 t/km². Range of its spatial variation is even higher: 1.1-6.0 t/km²; it depends on evenness of species composition and abundance of dominant species; generally both total abundance and species richness increase from the north to the south, as boreal species are replaced by low-boreal and subtropical ones. From the other hand, the abundance and species richness increase from the shore toward the ocean: the total number of nekton species increases from 42 to 76, and the number of dominant species - from 4 to 10, so structure of the nekton community becomes more evened and polydominant. The highest abundance and species richness are observed in the Subarctic Front zone. Mean total biomass of nekton in the epipelagic layer of the surveyed area is estimated as 2442 · 10 3 t including 1.6-2.5 million t (37-60 %) of mesopelagic fish that was the major group of nekton in all years except 2012, when the biomass of mesopelagic fish was only 378 · 10 3 t (21 %) while the portion of salmons increased to 40 % because of extremely high biomass of pink salmon (27 % of the total nekton biomass). Year-to-year changes of the nekton abundance in the surveyed area are characterized by negative trend, with its minimal values in 2008, 2010, and 2012, but it is considered as a temporary tendency.

Seasonal change of the community of large-sized tintinnids (Ciliophora, Tintinnida) in Laizhou Bay

The abundance and seasonal change of large-sized tintinnids were studied in Laizhou Bay. Large-sized tintinnids were collected by vertical towing using a shallow sea type III plankton net (open area 0.1 m, mesh size 76 μm) during 9 cruises between May and November of 2011 and from March to April, 2012. The samples were fixed in formalin solution to a final concentration of 5% and counted using an inverted microscope in the laboratory. We sampled 8 stations to avoid fluctuations over a short time period. The purpose of this study was to characterize seasonal change of the large-sized tintinnid community. Maximum tintinnid species richness was 19 in August and minimum was 5 in May. Tintinnid abundance ranged from 0 ind./L to 318 ind./L. Average abundance at all stations was highest (63 ind./L) in July and lowest (2 ind./L) in March, and there was a secondary peak of 48 ind./L in May. The abundance of Codonellopsis mobilis and Tintinnopsis chinglanensis were more than 50 ind./L. Agglutinated species occurred from March to November, while the hyaline species only occurred from June to September when the temperature was > 15°C. Codonellopsis mobilis occurred from March to November. The number of dominant species ranged from 1 in May, to 8 in August. Codonellopsis mobilis was a dominant species during all time periods and this one species significantly influenced the pattern of total ciliate abundance. Using the average abundance data of 8 sta650 生 物 多 样 性 Biodiversity Science 第 22卷 tions, two distinct cluster groups were observed (30% similarity): cluster I (July to September) and cluster II (March to June, October to November). The cluster results showed that there was a seasonal change of the large-sized tintinnid community. Average abundance and species richness were not significantly correlated with temperature and salinity.

Functional and Taxonomic Diversity of Stinging Wasps in Brazilian Atlantic Rainforest Areas.

Vespoidea are the most functionally diverse superfamily of Hymenoptera. Ecological studies involving this family are primarily based on eusocial groups, including ants and social paper wasps. In the present study, we examine stinging wasp (Vespoidea) faunal diversity in the Atlantic Rain Forest, which is one of the most diverse and threatened ecosystems in the World. Three conservation areas were sampled employing a standardized sample protocol. Families and functional groups of Vespoidea were collected in each area, with the exception ants (Formicidae), and analyzed using diversity analyses, to generate taxonomic diversity and distinctness indices. Results indicated Pompilidae was the most diverse family, and the idiobiont parasitoid type was the most diverse functional group in the three study areas. Núcleo Picinguaba of the Parque Estadual da Serra do Mar was taxonomically and functionally the most diverse and species rich area. Parque Estadual Intervales showed the highest number of dominant species and diversity of koinobiont parasitoids, while the Rebio Sooretama exhibited a decrease in several diversity parameters.

The effects of liquid versus spray-dried Laminaria digitata extract on selected bacterial groups in the piglet gastrointestinal tract (GIT) microbiota

In this study, the effects of supplementing animal feed with a liquid and spray-dried fucoidan and laminarin extract, derived from the seaweed Laminaria digitata on the porcine gastrointestinal microbiota, specifically the communities of Lactobacillus, Bifidobacterium and enterobacteria were evaluated. Twenty four piglets were fed one of three diets over a 21-day period to determine the effect that each had on the bacterial communities. The dietary treatments were as follows; (1) control diet, (2) control diet plus spray-dried formulation of laminarin fucoidan (L/F-SD) extract, (3) control diet plus a liquid formulation of (L/F-WS) extract. Control diet consisted of wheat, soya bean meal, soya oil and a vitamin and mineral mixture. The L/F-SD and L/F-WS supplemented diets had equal proportion of 500 ppm laminarin and fucoidan. At the end of the 21 day feeding period all animals were sacrificed and samples were collected from the ileum, caecum and colon. Counts were determined for Lactobacillus, Bifidobacterium and enterobacteria. Plate count analysis revealed that the L/F-SD diet caused a statistically significant 1.5 log and 2 log increases in the Lactobacillus and Bifidobacterium counts of ileum samples respectively. A greater difference was observed with the L/F-WS diet in that Lactobacillus and Bifidobacterium increased by 2 log and 3 log respectively. Alterations in the Lactobacillus species composition of the gastrointestinal tract (GIT) were analysed using specific PCR - denaturing gradient gel electrophoresis (PCR-DGGE). The DGGE profiles indicated that Lactobacillus species richness decreased along the gastrointestinal tract i.e. the number of dominant species detected in the colon was less than those detected in the ileum and caecum irrespective of the diet consumed. Consumption of both the L/F-SD and L/F-WS diets resulted in a richer Lactobacillus species composition in the ileum, with the L/F-SD diet being associated the emergence of Lactobacillus agilis in the colon. The study indicated that the L/F-WS extract was superior to the L/F-SD extract in increasing the titre of beneficial bacteria in the gastrointestinal tract (GIT).

Biodiversity and structure of spider communities along a metal pollution gradient

The objective of the study was to determine whether long-term metal pollution affects communities of epigeal spiders (Aranea), studied at three taxonomic levels: species, genera, and families. Biodiversity was defined by three indices: the Hierarchical Richness Index (HRI), Margalef index (DM) and Pielou evenness index (J). In different ways the indices describe taxa richness and the distribution of individuals among taxa. The dominance pattern of the communities was described with four measures: number of dominant species at a site, percentage of dominant species at a site, average dominant species abundance at a site, and the share of the most numerous species (Alopecosa cuneata) at a site. Spiders were collected along a metal pollution gradient in southern Poland, extending ca. 33 km from zinc and lead smelter to an uncontaminated area. The zinc concentration in soil was used as the pollution index.The study revealed a significant effect of metal pollution on spider biodiversity as described by HRI for species (p = 0.039), genera (p = 0.0041) and families (p = 0.0147), and by DM for genera (p = 0.0259) and families (p = 0.0028). HRI correlated negatively with pollution level, while DM correlated positively. This means that although broadly described HRI diversity decreased with increasing pollution level, species richness increased with increasing contamination. Mesophilic meadows were generally richer. Pielou (J) did not show any significant correlations. There were a few evidences for the intermediate disturbance hypothesis: certain indices reached their highest values at moderate pollution levels rather than at the cleanest or most polluted sites.

Effect of water-loving bird colonies on zooplankton in littoral zones of water bodies of different types

Changes in zooplankton developing under the effect of waste products from water-loving bird colonies were studied in water bodies of different types. The trophic status index in the nesting area showed no difference from its background values in an oligomesotrophic water body but was decreased in mesoeutrophic and eutrophic-hypertrophic water bodies. The abundance and biomass of zooplankton in the oligomesotrophic and mesoeutrophic water bodies were consistently higher than background values, while in the eutrophichypertrophic water body they were higher only at the beginning and in the middle of the nesting period. Irrespective of the trophic state of water body, the species diversity of zooplankton in the zone of impact from bird colonies was increased, but the number of dominant species remained unchanged, and no mass development of species indicating high organic load was observed; the proportion of Rotifera in the total abundance and biomass of zooplankton was decreased, that of Copepoda was increased, and the abundance of Cladocera was found to increase with the degree of overgrowing. Among possible explanations, this specific response of zooplankton is most likely due to changes in the ratio of nitrogen and phosphorus in the water.

Discrepancies in Hydrophytic Determinations Produced by Three Vegetation Formulas Used for Wetland Delineations

We examined disagreement among three methods used in the USA to make hydrophytic vegetation determinations during wetland delineations: the Dominance Ratio (DR), the Prevalence Index (PI), and the FAC-neutral Dominance Ratio (FN-DR). We had two objectives: to determine whether the number of dominant species in a plot affects the percentage of hydrophytic vegetation determinations made by each of the three methods and, if so, to explain the mathematical origin of disagreements among the methods. We compared the percentage of hydrophytic vegetation determinations produced when each method was applied to 200,000 simulations. The PI was the most consistent method for making hydrophytic vegetation determinations. We found that the DR is biased toward nonhydrophytic vegetation when there is an even number of dominant plant species in a plot; it is biased toward hydrophytic vegetation when there is an odd number of dominants. As the number of dominant species and strata increased, there were >20% more hydrophytic determinations made when we used DR than when we used PI. The FN-DR was also biased; it consistently produced fewer hydrophytic determinations than the other methods. When the DR disagrees with hydric soil and hydrology indicators, delineators should re-examine vegetation using the plot-based PI approach.

Structure of multi-species ant assemblages (Hymenoptera, Formicidae) in the Mountain Crimea

The multi-species ant assemblages were studied in the Crimea Mountains, in 9 types of plant associations in the plateau pastures as well as on the southern and northern slopes of the Main Range. A list of 18 ant species with data on their distribution in biotopes and also layers and the structure of their foraging territories is given. The hierarchical organization of multi-species ant assemblages and different strategies of nest location of the influents depending on the dominant species and its territoriality were investigated. Territoriality of each dominant species was determined by the frequency of foraging areas without nests of other species. Depending on dominant territoriality and the number of dominant species, the following classification of multi-species assemblages is proposed. (1) Monodominant assemblages with weakly expressed territoriality of the dominant species. Low density of the workers of Camponotus aethiops in the foraging territory determines weak interactions with influent species. The settling pattern of the influents shows no evident dependence on the dominant. Weakly expressed territoriality of the dominant allows non-territorial species to exist on the dominant’s territory. Such species were not found in other types of ant assemblages. (2) Monodominant assemblages with strongly expressed territoriality of the dominant species. The settling pattern of the influents shows the subordinate species to avoid those of higher ranks in the hierarchy, thus decreasing the probability of conflicts. The influents settle in the neutral zones as well as in the foraging territory of the dominant, so as to reduce competition with the subdominant species Formica cunicularia. Such a strategy reduces the probability of interspecific conflicts in biotopes with fewer vegetation layers than in the forests. (3) Bidominant assemblages with a variable dendrobiont dominant are typical among forest assemblages. Coexistence of two dominant species is possible when foraging of one of them is completely or partly restricted to one vegetation layer. The subdominant species avoid settling in the foraging territory of the dominant that occupies the same layer. When the dendrobiont dominant Crematogaster schmidti drops out of the assemblage, it (and its role in the assemblage) is replaced by other dendrobiont species Lasius emarginatus which otherwise acts as the 1st order subdominant in C. schmidti assemblages. (4) Polydominant assemblages are characterized by the presence of as many as 3 dominant species, namely Crematogaster schmidti, Camponotus aethiops, and Plagiolepis tauricus. The coexistence of the dominants is possible due to use of different layers (one species is a dendrobiont, the other two are herpeto-hortobionts), different activity periods (round-the-clock in Crematogaster schmidti, night in Camponotus aethiops, and daytime in P. tauricus), and different size classes of the workers (3rd, 5th, and 1st, respectively). The different size classes of workers reduce competition for food. Thus, when the number of dominant species in the assemblage increases, so does the number of mechanisms facilitating their coexistence.

Changes in the planktonic copepod community in a landlocked bay in the subtropical coastal waters of Hong Kong during recovery from eutrophication

Tolo Harbour is a poorly flushed bay in the northeastern corner of Hong Kong. Eutrophication caused by discharge of untreated and secondarily treated sewage into the bay was first detected during the 1970s. Increased nutrient input led to a noticeable increase in algal biomass and algal bloom occurrences. Nutrient reduction measures, including the construction of a pipeline to export all sewage effluents from Tolo Harbour, were introduced during the late 1980s. Decline in nutrient levels and decrease in the number of algal blooms have been recorded since 1998 when all nutrient reduction measures became fully operational. Zooplankton samples collected during 2003–2004 revealed that Tolo Harbour still contained a higher density and lower diversity of planktonic copepods compared to Mirs Bay, a less-polluted sea area outside Tolo Harbour. A comparison between data collected in this study to those collected during 1988–1990, several years before nutrient reduction measures were to be fully implemented, showed a decrease in copepod densities and an increase in copepod diversity. Small copepods, notably species of Paracalanus and Oithona, dominated the copepod communities in both periods, but there was an increase in species evenness during 2003–2004, caused by an increase in the number of dominant species. These observations confirm that eutrophication may lead to increases in copepod densities accompanied by increased dominance of small species.

What determines the number of dominant species in forests?

In this work, the difference in number of dominant species in a community on global scale and successional trajectories was analyzed based on the published data. We explained the reasons of these differences using a resource availability hypothesis, proposed in this work, that the distribution of available resource determined the pattern of community dominance. The results showed that on global scale the number of dominant species of community varied across latitudinal forest zone, namely from single-species dominance in boreal and temperate forest to multi-species codominance, even no dominant species in tropical forest. This was consistent with the pattern of resource distribution on global scale. Similarly, in successional trajectories, the number of dominant species gradually radiated from single-species dominance to multi-species codominance, even no dominant species in tropical forest. The changing available resources in trajectories were responsible for this difference. By contrary, a community was often dominated by single species in temperate or boreal forest. This was determined by the low available resource, especially low available water and temperature. In boreal forest, low temperature greatly reduced availability of water and nutrient, which were responsible for the single-species dominance. In addition, the conclusion that high available resources sustained low dominance of community might be deduced, based on the fact that the dominance of community declined with the increasing of species diversity. To sum up, the richer the available resources were, the lower the dominance of community was, and vice versa. The hypothesis that the resource availability controlled the dominance of community could well elucidate the difference of community dominance on global and community scale.

COMMUNITY CHARACTERISTICS OF SHRIMPS IN THE OFFSHORE WATERS OF THE MID-SOUTHERN EAST CHINA SEA

Based on the data of the shrimp resources sampled by single trawler as investigation boat in 18 stations in the offshore waters of the Mid-Southern East China Sea (26°00'N—28°30'N,121°00'E—126°00'E) in May,August,November,2006 and February,2007,total catch from each trawler was counted and identified to species in taxonomy,and the spatial variation of the shrimp species composition,index of relative importance (IRI),the diversity and similar characteristics of the community structure were analyzed. 32 species of shrimp were caught in this survey,which belonged to 22 families under 11 genera. Comparison of the amounts of various species in different seasons:there are 22 species in the autumn which are the most; 20 species in winter,17 and 18 species in the spring and the summer respectively. According to the standard of index of relative importance (IRI) (the species with IRI above 1000 were regarded as the dominant species in this paper),there were 10 dominant species:Metapenaeopsis longirostris,Metapenaeopsis dalei,Solenocera alticarinata,Plesionika izumiae,Ibacus novemdentatu,Parapenaeus fissuroides,Solenocera koelbeli,Solenocera crassicornis,Parapenaeopsis hardwickii and Solenocera crassicornis,and 5 of them were major dominant species which were Metapenaeopsis longirostris,Metapenaeopsis dalei,Plesionika izumiae,Parapenaeus fissuroides and Parapenaeopsis hardwickii. Defined the ones with IRI values ranging from 100 to 1000 as common species,we got 7:Metapenaeopsis barbata,Penaeus japonicus,Plesionika dentirostris,Palaemon gravieri,Alpheus japonicus,Parapandalus spinipes and Sicyonia cristata. The abundance of the dominant species was varied with seasons. For example,5 were in May:Metapenaeopsis longirostris,Metapenaeopsis dalei,Parapenaeopsis hardwickii,Solenocera alticarinata and Plesionika izumiae,89.15% of the total catch and 92.14% of the total individuals. In August,there were 7 dominant species:Metapenaeopsis dalei,Plesionika izumiae,Metapenaeopsis longirostris,Parapenaeus fissuroide,Solenocera crassicornis,Ibacus novemdentatus and Solenocera alticarinata,91.82% of the total catch and 95.05% of the total individuals. In November,the number of dominant species increased to 8:Metapenaeopsis longirostris,Plesionika izumiae,Parapenaeus fissuroides,Metapenaeopsis dalei,Solenocera crassicornis,Ibacus novemdentatus,Solenocera koelbeli and Solenocera alticarinata,occupying 95.31% and 97.56% of the total catch individuals,respectively. In February,the number reduced to 5:Metapenaeopsis longirostris,Parapenaeus fissuroides,Metapenaeopsis dalei,Solenocera koelbeli and Plesionika izumiae,88.76% and 94.93% respectively. Based on their adaptability to habitats,all recorded species of shrimps were categorized into the hyperthermal and hysaline community in the Mid-Southern East China Sea. The stations with high abundance were mainly located in the west of the 120m isobaths,and gradually lower toward the autumn to winter,while it reached the lowest in winter. Margalef index (D) and Shannon-Wienner index (H') were higher in summer and autumn than those in winter and spring,Pielou's evenness index (J') in the offshore waters of the Mid-Southern East China Sea was stable through every season. The result indicated that the diversity index west of the 120m isobaths was higher than in the east. By hierarchical cluster analysis and non-metric multidimensional scaling (NMDS) assisted analyzing,the types of shrimp assemblage determined by influential factor such as aquatic system,water mass and salinity etc. in the East China Sea in spring were also discussed in the article,two main assemblages were identified in the offshore waters of the Mid-Southern East China Sea,which were deeper costal shrimp assemblage and out shelf sea shrimp assemblage.

The effect of hydrological and morphometric parameters of temporary waterbodies on the structure and abundance dynamics of crustacean zooplankton

The effects of hydrological conditions and morphometry of the temporary waterbodies on the structure, abundance, and biomass of crustacean zooplankton are described. This study was performed in the southeast of the European part of Russia. The existence duration (hydrological regime) of the temporary waterbodies has the most profound effect on the zooplankton patterns. A significant effect was observed for the number of dominant species, the zooplankton biomass, the calanoid-cyclopoid ratio, and the Shannon index. The brackish lagoons were characterized by the highest biodiversity and abundance and the lowest values of these parameters were found in the steppe puddles and waterbodies of terraces above the flood-plain in the river valleys.

국내 해양식물플랑크톤의 주요종과 분포에 대한 조사

문헌 32편에서 조사된 출현종수는 최저 43종에서 최고 200종까지 기록되고, 그 중에서 주요종수는 최저 2종에서 최고 27종까지로 종수의 기록에 상당한 차이를 보였다. 본 조사에서 기록한 주요종의 목록은 모두 50속 116종이었고, 규조류 34속 89종(76.6%), 와편모조류 11속 22종(18.9%), 황갈색조류 2속 2종(1.7%), 남조류, 라피도조류, 유글레나조류가 각각 1속 1종(0.9%)이었다. 생태적 특성을 반영하는 주요 종으로는 우점종이 Actinoptychus seranius를 비롯하여 79종, 출현빈번종이 Coscinodiscus centralis를 비롯하여 50종, 적조원인종이 Cochlodinium polykrikoides를 비롯한 36종이었다. 또한 3가지의 주요 특성을 모두 지닌 종은 Prorocentrum micans를 비롯한 11종이었다. 여러 문헌에서 주요종으로 언급했던 종은 규조류인 Skeletonema costatum이었고 단일 속(genus)으로서 18종의 많은 종이 조사된 속은 Chaetoceros속이었다. This survey was carried out to assess important species of phytoplankton in the ocean and bay in Korea from 32 references. The number of important species assessed from 50 genera 116 species. Of them, Bacillariophycea(diatoms) 34 genera 89 speceis(76.6%), Dinophyceae(dinoflagellates) 11 genera 22 species(18.9%), Chrysophyceae 2 genera 2 species(1.7%), Cyanophycea(blue-green algae), Raphidophyceae, Euglenophyceae(euglenoids) 1 genera 1 species(0.9%) respectively. By ecological characters, the number of dominant species were 79 species including Actinoptychus seranius, 50 species including Coscinodiscus centralis were recorded as frequently apperaing species and 36 species including Cochlodinium polykrikoides were recorded as red-tide causative organism. Also, 11 species including Prorocentrum micans were surveyed as the indicator including all ecological characters.

Effects of different field management systems on the carabid coenosis in oil seed rape with special respect to ecology and nutritional status of predacious Poecilus cupreus L. (Col., Carabidae)

It could be shown, that the differences between two carabid populations on rape fields under intensive management and reduced management (50% N‐input, no insecticide application) were not as striking as one might expect. Despite the fact that total individual numbers of the carabid populations, total species numbers, and number of dominant species were clearly higher in the field under reduced management, RENKONEN’s Re showed only a slight difference between the fields with nearly three‐quarter correspondence in dominance structure. The presence of five more carabid species on the field under reduced management is underlined by the low values of JACCARD’s species identity and WAINSTEIN’s Kw index of similarity. On the other hand, according to SHANNON‐WEAVER’s Hs for species diversity and SHANNON’s Es for evenness, the differences between the fields are minor. Even if only the dominant species were taken into account, the similarity between both fields was obvious, despite the fact that in the field under reduced management two more dominant carabid species were found. In both fields, phytophagous Amara similata was the most abundant species. Nevertheless, a special oil seed rape carabid coenosis seems to exist as well, as one was found for cereal crops and for root crops, which might consist of A. similata, Amara aenea, Harpalus affinis, Poecilus cupreus, Pseudophonus rufipes, and Pterostichus melanarius.For P. cupreus, which was chosen as a typically predacious and beneficial carabid species in oil seed rape, biomass, fecundity and determination of the degree of gut filling also showed no differences for the fields. Even the length of elytrae as an indicator for nutritional situation in the preceding year showed no difference. Only the phenology of P. cupreus showed an obvious shift of the peak in activity‐density in the intensively managed field, to a later date in the season, compared with the field under reduced management. The latter reflects the usual spring peak. No sufficient explanation was found for the peak 4 weeks later on the intensively managed field. It can be assumed that a less sufficient food supply (higher numbers of potential food, e.g. larvae of Meligethes spp. in the field under reduced management), due to insecticide input, or long‐term biocide impact on P. cupreus, or a faster growth of rape plants due to high nitrogen input resulting in a less favourable microclimate on the intensively managed field, was responsible for this later peak in activity‐density.To conclude, the relations between the predacious carabids, their potential prey, and the abiotic factors in the habitats seem to be much more complicated than assumed. There is a strong hint that the impact of single parameters such as field management influencing the phenology change obviously over the carabids activity period.

Diversity and stability of fishes (Teleostei) in a temporary river of the Brazilian semiarid region

The effects of hydrological disturbances by flooding and drought on the diversity and stability in a temporary river fish community in the Brazilian semiarid region were analyzed over the 1996 hydrological cycle. Twelve collections of fishes were made during the wet and dry phases, and 789 individuals of 16 species were collected. Diversity was measured using Simpson's Index (S) and community stability was analyzed by the variation in abundance using Kendall's W concordance test. Fish diversity in the Taperoa river was subjected to hydrological disturbances by flooding and drought. During the wet phase the diversity was higher (S = 0.855) than during the dry phase (S = 0.771). The community was considered stable during the whole annual hydrological cycle (W = 0.418 p < 0.001), but a higher stability in the community was found during the dry phase. During the dry phase the number of dominant species was smaller than during the wet phase.