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1.
Benthic faunal associations on soft substrates at Potter Cove, King George Island, Antarctica 总被引:4,自引:3,他引:1
Associations of benthic invertebrates from Potter Cove (Antarctica) were defined from photo-transects. Density, percentage
cover, species richness S′, diversity index H′, evenness index J′ and mean-size estimations were studied in relation to water
depth down to 30 m. A clear bathymetric pattern was evident, with two different communities at 15 and 30 m, and a transition
area between 20 and 25 m. At 15 m we observed a small number of taxa (nine in total), a high percentage of bare substratum
(95%), and the dominant species were pennatulids and the bivalve Laternula elliptica. From 20 to 30 m the dominant species was the ascidian Molgula pedunculata and there was a slight increase in S′, H′ and J′, as well as in the mean size of individuals, especially in M. pedunculata, while the proportion of bare substratum showed a constant decrease with depth. Using multivariate analyses, three faunal
assemblages related to depth were defined and a strong association of some species, mainly predators and opportunistic necrophages,
with M. pedunculata was revealed. Ice impact (icebergs and anchor ice) seems to be the major regulating factor of benthic assemblages in shallow
waters.
Received: 28 April 1997 / Accepted: 17 August 1997 相似文献
2.
R. Galzin S. Planes M. Adjeroud C. Chauvet P. J. Doherty J. Poupin 《Coral reefs (Online)》1998,17(1):15-21
The 9 km2 uplifted lagoon of Taiaro Atoll (15°45′S, 144°38′W) is hypersaline due to its isolation from the ocean, yet it contains a
high diversity of fish. The question unifying our expedition was to discover whether these assemblages could be self-sustaining
despite very limited contact with the ocean. Although we were constrained by time, collections of fish larvae showed that
some species can complete their life-cycle within the lagoon, while others differed genetically between the lagoon and the
ocean, consistent with restricted gene flow. The lagoon contained few oceanic species of zooplankton, confirming its general
isolation, but nevertheless some fish species may depend upon infrequent colonisation from the ocean (when large waves drive
water over the normally dry reef crest). Isotopic signatures in fish otoliths suggest the basis for a more definitive and
inclusive test of the sources of the lagoonal assemblage.
Accepted: 28 August 1997 相似文献
3.
Picophytoplankton biomass, community structure and productivity in the Great Astrolabe Lagoon, Fiji 总被引:4,自引:0,他引:4
Phytoplankton biomass, community structure and productivity of the Great Astrolabe lagoon and surrounding ocean were studied
using measurements of chlorophyll concentration and carbon uptake. The contribution of picophytoplankton to biomass, productivity
and community structure was estimated by size fractionation, 14C-incubation and flow cytometry analysis. Picoplankton red fluorescence was demonstrated to be a proxy for chlorophyll <3 μm.
Consequently, the percentage contribution to chl a<3 μm from each picoplankton group could be calculated using regression estimated values of ψ
i
(fg chl a per unit of red fluorescence). In the lagoon, average chlorophyll concentration was 0.8 mg m-3 with 45% of phytoplankton <3 μm. Primary production reached 1.3 g C m-2 day-1 with 53% due to phytoplankton <3 μm. Synechococcus was the most abundant group at all stations, followed by Prochlorococcus and picoeukaryotes. At all stations, Prochlorococcus represented less than 4% of the chl a <3 μm, Synechococcus between 85 and 95%, and Picoeukaryotes between 5 and 10%. In the upper 40 m of surrounding oceanic waters, phytoplankton
biomass was dominated by the >3 μm size fraction. In deeper water, the <1 μm size fraction dominated. Prochlorococcus was the most abundant picoplankton group and their contributions to the chlorophyll a<3 μm were close to that of the picoeukaryotes (50% each).
Accepted: 27 May 1999 相似文献
4.
Eleanor B. Mackay Ian D. Jones Andrew M. Folkard Stephen J. Thackeray 《Hydrobiologia》2011,666(1):85-97
Community structure and diversity patterns of pelagic copepods were investigated for the coastal areas and in the marine lakes
of the Palau islands in the West Pacific. We conducted field surveys during 2004–2007 and collected zooplankton samples from
eight coastal areas and 16 marine lakes. The marine lakes in the islands of Palau are limnologically classified into two types,
meromictic and holomictic lakes. Species diversity indices (Margalef’s species richness d′, Shannon–Wiener index H′, and Simpson’s dominance) were measured at each sampling site. The copepod community structure was analyzed using multivariate
analyses, hierarchical cluster analysis, and non-metric multidimensional scaling (MDS) from the PRIMER package. A total of
36 copepod taxa were identified to the genus or species level from Calanoida, Cyclopoida, Harpacticoida, and Poecilostomatoida.
Multivariate analysis based on the Bray–Curtis similarity index revealed that copepod assemblages could be classified into
three different groups according to their habitat: (I) meromictic lakes, (II) holomictic lakes with an exceptionally shallow
and flat basin (type A holomictic lakes), (III) holomictic lakes with a deep basin (type B holomictic lakes), and all coastal
areas. The meromictic lakes were characterized by markedly decreased species diversity (d′ = 0.15, H′ = 0.41) in which only two brackish-water species, Bestiolina similis and Oithona dissimilis, were dominant. Type A holomictic lakes were characterized by relatively low levels of species diversity (d′ = 1.25, H′ = 1.35). In contrast, type B holomictic lakes were characterized by relatively high levels of species diversity, which was
comparable to that of coastal areas. This result indicated that zooplankton assemblages in the type B holomictic lakes were
closely related to a coastal community. The present study showed that the species diversity of pelagic copepods varies according
to the level of isolation and the local environmental conditions for each marine lake. 相似文献
5.
Summer plankton beneath the McMurdo Ice Shelf at white Island,McMurdo Sound,Antarctica 总被引:3,自引:3,他引:0
The zooplankton of the under-shelf-ice ecosystem at White Island (78°10′ S, 167°30′ E), McMurdo Sound, Antarctica was investigated during December 1976 and January 1977. The water column was sampled through
a hole in the McMurdo Ice Shelf over a water depth of 67 m. Seawater temperatures under the ice shelf ranged from −1.91 to
1.96°C. Dissolved oxygen levels ranged from 5.0–6.05 ml l-1 in early December to 4.65–4.8 ml l-1 in late January. Current speeds of up to 0.13 m s-1 were recorded at a depth of 50 m and a predominantly northward flow was detected. Light levels under the shelf ice were low
with less than 1% of the incident light being transmitted to a depth of 3 m. No chlorophyll a was detected within the water column throughout the investigation. Mean zooplankton biomass values in the water column ranged
from 12 to 447 mg wet weight m-3 and were similar to values recorded elsewhere from Antarctic inshore waters, but were very much higher than those recorded
from under seasonal sea ice in McMurdo Sound. Thirty-two zooplankton species were recorded including 1 ostracod, 21 copepods
(10 calanoids, 3 cyclopoids and 8 harpacticoids), 4 amphipods, 2 euphausiids, a chaetognath and 3 pteropods. Larvae of polychaetes
and fish were found on some occasions. The species composition in general was similar to that recorded from McMurdo Sound
and other Antarctic inshore localities. Among the Copepoda, however, there were a number of species, especially among the
Harpacticoidea, that have not been found previously in McMurdo Sound and the Ross Sea, but that are known to be associated
with ice in other localities in Antarctica. Two recently described species are known only from White Island. They were present
in the water column but were most abundant in the surface water of the tide crack where they were the most abundant zooplankters.
The tide crack, which probably is an extension of the under-ice habitat, is apparently a significant nursery area for amphipods
and copepod species.
Received: 23 November 1994/Accepted 7 May 1995 相似文献
6.
Taiaro Atoll Lagoon is normally isolated from the ocean, but at least 125 marine fish species of 31 families are present
there. We sampled fish larvae in Taiaro Lagoon and the nearby ocean in February 1994 with plankton net, neuston net and light
trap to investigate which taxa were completing their life cycles in the lagoon. Concentrations of fish eggs and larvae were
very high in the lagoon indicating intense spawning, but larvae of only 18 taxa of 10 families were present. Only six, a callionymid,
gobiids, a hemiramphid, a microdesmid, and two pomacentrids, were present across a full range of pelagic sizes, and were clearly
completing their pelagic stage in the lagoon. Four other taxa, an apogonid, two labrids and a scarid, were common, but the
largest individuals were small (<5 mm) postflexion larvae. These may have been completing their pelagic stage in the lagoon.
The remaining lagoonal larvae (eight taxa) were rare and at the preflexion stage, so we could only conclude that they hatched
from eggs spawned in the lagoon. Nineteen taxa of 15 families found as adults in the lagoon were present outside the lagoon
as larvae, but not inside, suggesting that they may not normally complete their life cycles in the lagoon. Horizontal distributions
of larvae in the lagoon are apparently due to the interaction of larval vertical distribution behaviour with a wind-driven
countercurrent system.
Accepted: 16 October 1996 相似文献
7.
A spectacular mound-like reef formation (126 m in circumference, 10 m high) dominated by highly arched and record-size colonies
of the unattached mushroom coral Halomitra pileus, along with 17 other species of the family Fungiidae, occurs in 31 m of water on the sedimentary lagoon floor of the Great
Astrolabe Reef, Fiji. Core samples show radiocarbon dates which indicate that the formation hypothetically began building
∼4500 y ago, with a calculated mean accretion rate of 2.2 mm ⋅ y-1. The majority of fossil and living material is contributed by H. pileus colonies between 40–70 cm mean diameter, with some individuals up to 1.5 m in diameter. The size, fungiid diversity, and
geological history of the bioherm is unprecedented and represents the first example of a coral reef constructed almost entirely
by Fungiidae.
Accepted: 29 July 1996 相似文献
8.
Jean Carlos Budke João André Jarenkow Ary Teixeira de Oliveira-Filho 《Plant Ecology》2007,189(2):187-200
The relationships among floristic, structural and physiognomic variables of the tree component, flooding regime variations
and soil fertility were investigated in a riparian forest fragment (ca. 43 ha) in the Rio Botucaraí watershed near the confluence
with the Rio Jacuí, southern Brazil. All the trees with a dbh ≥ 15 cm were surveyed in 100 contiguous 10 × 10 m plots
and soil chemical and textural variables were obtained from the analyses of 15 topsoil samples (0–20 cm depth) collected at
different locations. The sample sites encompass all the topographic variation of the area. We used canonical correspondence
analysis (CCA) to seek correlations between environmental variables and tree component distribution. The 1,547 surveyed individuals
belonged to 30 species and 16 botanical families. The Shannon diversity index (H′) and the Pielou equability (J′) were 1.995
and 0.586 nats ind.−1, respectively. Sebastiania commersoniana, Casearia sylvestris, Eugenia uniflora and Eugenia hyemalis presented the highest importance values. Species’ densities chiefly correlated with site elevation, flooding regime and soil
chemical fertility. The analyses of ecological categories (EC) revealed that most species are heliophylous and typical of
early successional stages. Richness and diversity (P < 0.001) variations from different topographic positions reflect that at the local scale, flooding was a limiting factor
for the establishment of certain species suggesting that local processes control species richness and diversity. 相似文献
9.
Skeletal δ13C levels in symbiotic reef corals are believed to be predominantly influenced by metabolic fractionation. Therefore, environmental
variables influencing coral metabolism should also affect skeletal δ13C levels. To test this hypothesis, we measured the effects of light (which drives photosynthesis) and relative zooplankton
levels (heterotrophy) on skeletal δ13C values in the corals Pavona clavus and P. gigantea at two depths (1 m and 7 m). For both species, decreases in light or increases in zooplankton resulted in significant decreases
in skeletal δ13C levels. A significant decrease in δ13C values with depth was observed in Pavona gigantea only. Thus, light and zooplankton directly affect coral skeletal δ13C values, supporting the hypothesis that metabolic fractionation significantly contributes to skeletal δ13C levels. Simultaneous decreases in both light and zooplankton resulted in decreases in skeletal δ13C values, reflecting decreases in light. In Pavona clavus, intra-annual variation in skeletal δ13C values over one year correlated with seasonal changes in irradiance. Further study is needed to resolve how skeletal δ13C values vary at intermediate levels of irradiance and zooplankton, and in other coral species.
Accepted: 14 July 1998 相似文献
10.
Well-preserved, Holocene coral reefs provide the opportunity to discriminate between models of intrinsically driven succession
and extrinsically driven species replacement, especially when paleontological patterns can be combined with ecological observations
of the underlying mechanisms. Rhomboid shoals in the central shelf lagoon of the Belizean Barrier Reef experienced a recent
and dramatic change in community composition. Agaricia tenuifolia replaced Acropora cervicornis as the dominant coral species at 3–15 m depth along the flanks of the reefs. We tested the hypothesis that shallowing upward
caused this shift in dominance. A core extracted from 0.5 m water depth on one of the shoals, Channel Cay, revealed a shallowing-upward
shift in dominance from Acropora to Porites divaricata. This successional sequence was quite different from the Acropora-to-Agaricia transition observed in four cores from 6–11 m water depth. Ecological observations showed that Agaricia became the dominant at ≥3 m depth after Acropora populations were decimated by a regional outbreak of white-band disease. The Acropora-to-Agaricia transition was clearly a case of extrinsically driven species replacement rather than an intrinsically driven, successional,
shallowing-upward sequence.
Accepted: 14 May 1998 相似文献
11.
P. S. Kench 《Coral reefs (Online)》1998,17(2):155-168
Detailed measurements of water levels, and tide and wave-induced currents were undertaken to examine physical processes and
their relationship with morphology in the Cocos (Keeling) Islands, a medium sized atoll in the Indian Ocean. Results indicate
that the atoll structure controls both lagoon circulation and the spatial pattern of energy distribution. Lagoon circulation
is tide dominated (currents 16–31 cms-1) with flushing (2–5 days) of the lagoon occurring through the deep leeward passages. Wave- and tide-driven unidirectional
flows through shallow passages (26–65 cms-1) are important mechanisms of ocean to lagoon water exchange and contribute up to 24% of the lagoon neap tide prism. Reef
flats are dominated by wave energy (maximum velocity 140 cms-1, east) with measurements of the attenuation of wave energy between reef flats and shallow lagoon (80–90%) conforming to measurements
from fringing and barrier reefs. Spectral analysis shows that the characteristics of wave energy vary on different sectors
of the atoll, with gravity wave energy dominating the east, and infragravity wave energy dominating the southern reef flat
and passages. Wave setup at the reef crest is considered to be responsible for an identified 0.1 m higher water level in the
southern as opposed to eastern and northern atoll, which promotes higher reef flat growth. Transmission of gravity waves across
reef flats requires threshold water depths of 0.65 (east) and 0.70 m (south). The higher southern reef is an effective filter
of gravity wave energy for most tidal elevations. Differences in the type and magnitude of physical processes within the atoll
are discussed with relation to geomorphic development on Cocos.
Accepted: 28 February 1998 相似文献
12.
Raphaël N’doua Etilé Aka Marcel Kouassi Maryse N’guessan Aka Marc Pagano Valentin N’douba N’guessan Joël Kouassi 《Hydrobiologia》2009,624(1):171-189
Zooplankton constitutes a sensitive tool for monitoring environmental changes in coastal lagoons; however, the available information
on zooplankton communities is not sufficient to optimize their rational management. The relationships between zooplankton
distribution and environmental factors were studied in a tropical lagoon to test whether the indicator properties of zooplankton
assemblages could be used to monitor water quality, in a context of expected eutrophication provoked by an increasing anthropogenic
activity. Twenty-one (21) stations were sampled monthly from January to December 2004. The community was composed of 65 taxa
including Copepoda, Rotifera, and Cladocera. Copepoda was the most abundant group (81% of total numbers). The main zooplankton
species were Oithona brevicornis, Acartia clausi, and Brachionus plicatilis. The highest zooplankton abundance (171–175 ind. l−1) was recorded during the long, dry season (February–April) and the lowest (40–45 ind. l−1) during the rainy and the flood periods (June–July). At a spatial level, the lowest abundance was observed in the estuarine
zone. During the dry seasons (December–April and August–September), marine zooplankton taxa were abundant near the channel
of Grand-Lahou, and brackish water taxa dominated in the other sites. Multivariate analyses (Co-inertia) showed that the composition
of zooplanktonic communities and their spatio-temporal variations were mainly controlled by salinity variations closely linked
to the climatic and hydrological context. The role of the trophic state on zooplankton communities could not be clearly evidenced.
Our results and a comparison with previous studies in the neighboring, highly polluted Ebrié Lagoon suggest that the ratio
between Oithona and Acartia abundance could be used as biological indicator for the water quality.
Handling editor: S. I. Dodson 相似文献
13.
The seasonal variations in biomass, abundance and species composition of zooplankton in relation to hydrography and chlorophyll
a were studied in the subarctic waters north of Iceland. The sampling was carried out at approximately monthly intervals from
February 1993 to February 1994 at eight stations arranged along a transect extending from 66°16′N–18°50′W to 68°00′N–18°50′W.
The mean temperature at 50 m depth showed a clear seasonal pattern, with lowest water temperatures in February (∼1.1°C) and
the highest in July (∼5.4°C). The spring growth of the phytoplankton began in late March and culminated during mid-April (∼7.0 mg
Chl a m−3). Both the biomass and the abundance of total zooplankton were low during the winter and peaked once during the summer in
late May (∼4 g m−2 and ∼38,000 individuals m−2). A total of 42 species and taxonomic groups were identified in the samples. Eight taxa contributed ∼90% of the total zooplankton
number. Of these Calanus finmarchicus was by far the most abundant species (∼60% of the total zooplankton). Less important groups were ophiuroid larvae (∼9%),
Pseudocalanus spp. (∼8%), Metridia longa (∼4%), C. hyperboreus (∼3%), Acartia longiremis (∼2%), chaetognaths (∼2%) and euphausiid larvae (∼2%). The dominant copepods showed two main patterns in seasonal abundance:
C. finmarchicus, C. hyperboreus and C. glacialis had one annual peak in numbers in late May, while Pseudocalanus spp., M. longa and A. longiremis showed two maxima during the summer (July) and autumn (October/November). Ophiuroid larvae and chaetognaths (mainly Sagitta elegans) peaked during the middle of July, while the number of euphausiid eggs and larvae was greatest from May to July. The succession
in population structure of C. finmarchicus indicated its main spawning to be in April and May, coincident with the phytoplankton spring bloom. A minor spawning was
also observed sometime between August and October. However, the offspring from this second spawning contributed only insignificantly
to the overwintering stock of C. finmarchicus.
Received: 12 September 1997 / Accepted: 1 March 1998 相似文献
14.
We analysed qualitative winter zooplankton samples, collected from the ocean surface, to test portions of proposed life-cycle
models for Calanus propinquus. Nine zooplankton hauls were taken in the Bransfield Strait area during June 1996. Results show that C. propinquus is present in the ocean surface in winter. However, its presence seems to be related to ice coverage below 30%.
Received: 31 October 1997 / Accepted: 23 February 1998 相似文献
15.
南沙群岛美济礁海域夏季浮游动物群落特征 总被引:7,自引:0,他引:7
浮游动物是珊瑚礁生态系统中的重要组成部分,但国内相关研究相对较少。利用2012年7月在南沙群岛美济礁海域开展的13个站次的海洋生物调查数据,对美济礁浮游动物的群落特征进行研究,表明:(1)美济礁浮游动物种类组成丰富,共出现15个类群138种(类)浮游动物;(2)优势种组成复杂、区域变化明显,单一种的优势度不高;(3)浮游动物平均密度和湿重生物量分别为117.70个/m3、69.01 mg/m3,浮游幼虫在总密度中所占比例最大;(4)浮游动物非常丰富,多样性程度较高。平均丰富度、多样性指数和均匀度分别为4.93、3.33和0.67;(5)浮游动物可划分为2个群落,分别为潟湖-礁坪区群落和向海坡群落;(6)受珊瑚礁不同生物地貌带的空间异质性和水动力条件的影响,美济礁浮游动物群落区域差异明显。潟湖区浮游动物多样性较高,生物量最低;礁坪区浮游动物数量大,但分布不均匀,且多样性水平最低;向海坡区浮游动物种类最多、多样性非常丰富,但栖息密度最低。 相似文献
16.
Tetsu Hirata 《Ecological Research》1991,6(1):101-111
From percentage covers of sessile organisms obtained over about 3 yr by suspending concrete plates at depths of 1.0, 2.5,
4.0 and 5.5 m in Nabeta Bay, Shimoda, Pacific coast of Japan, changes of five indices of community structure, i.e. number
of species (S), Shannon-Weaver diversity (H′), evenness (J′), McNaughton's dominance (MD) and Horn's similarity (HS), were investigated throughout succession. Colonization curves became
horizontal after reaching a maximum at 6 months after immersion at all depths. The number of species appeared to approach
equilibrium during the first year of immersion. In the period from 13 to 37 months after immersion, the five indices indicated
that communities at the upper two depths had stabilized structures within a limited range of variation, as represented by
low HS values, whereas those at the lower two depths had simplified structures, as indicated by low S orH′ values. Furthermore, the results of cluster analysis of samples at four depths indicated that 13 to 37-month communities
at the upper two depths had advanced, converged structures, whereas those at the lower depths had young, non-converged structures.
The stability of community structure observed at the upper two depths could be due to domination of two long-lived species,
the kelpEisenia bicyclis and the oysterCrassostrea nippona. On the other hand, the simplification of community structure at the lower two depths seems to be due to reduced domination
of these two species as a result of disturbances such as scouring by sand.
Contributions from the Shimoda Marine Research Center, No. 514. 相似文献
17.
A study of feeding ecology in Trematomus hansoni Boulenger 1902 and Trematomus loennbergii Regan 1913 was carried out from samples collected in the austral summer 1990–1991 off Terra Nova Bay, Ross Sea. T. hansoni was caught between 35 and 566 m and T loennbergii between 311 and 543 m. Stomach contents analysis shows that T. loennbergii relies on a wider range of prey than T. hansoni. Fish and decapods are the main food resources of T. loennbergii, which feeds also on epifaunal and tube-dwelling polychaetes. T. hansoni mostly relies on fish resources that are made up of juvenile stages of fish and eggs. Despite the common area occupied by
the two species, the interspecific competition is mostly mitigated due either to taking different prey or to taking different
amounts of the same prey.
Received: 31 October 1995/Accepted: 20 February 1996 相似文献
18.
A. Mohanty J. P. Martín I. Aguinagalde 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(8):1304-1310
High chloroplast DNA (cpDNA) diversity was found within and among populations of Prunus spinosa sampled from seven European deciduous forests. A study of 12% of the total chloroplast genome detected 44 mutations, which
were distributed over 24 haplotypes; four were common to two or more populations and the rest were unique haplotypes. The
most-abundant and widely distributed haplotype was H2 (frequency = 41% approximately). Six of the seven populations were polymorphic.
All of the six polymorphic populations had ”private” haplotypes (frequency < 5%) in addition to common haplotypes. The UPGMA
dendrogram demonstrated a correlation between populations and their geographical locations. The total diversity was high (hT = 0.824) and a major portion of it was within populations (hs = 0.663). The level of population subdivision for unordered alleles was low (GST = 19.5%) and for ordered alleles was lower (NST = 13.6%). No phylogeographic structure could be demonstrated in the present geographical scale. High polymorphism in the cpDNA
of P. spinosa has to be considered carefully when planning phylogenetic studies involving this species.
Received: 20 September 1999 / Accepted: 10 November 1999 相似文献
19.
J.-P. Torréton 《Coral reefs (Online)》1999,18(1):43-53
Biomass, production and heterotrophic activity of bacterioplankton were determined for two weeks in the Great Astrolabe Reef
lagoon, Fiji. Bacterial and Bacterial activities were distributed homogeneously throughout the water column (20 to 40 m deep)
and varied little from site to site inside the lagoon. Bacterioplankton biomass and production also varied little over a diel
period with coefficients of variation of 9 and 22%, respectively. On average, over the whole study, bacterial abundance was
0.77×109 cells l-1 and bacterial production averaged 0.36 μg-at. C l-1 d-1. Bacterial abundance and production were greater in the lagoon than in oceanic waters. Attachment to particles seems to provide
an advantage for bacterioplankton growth because specific growth rates for attached bacterioplankton were, on average, significantly
greater than that of the free community. Growth efficiency, determined by correlating the net increase of bacterial biomass
and the net decrease of dissolved organic carbon (DOC) in dilution cultures, was very low (average 6.6%). Using carbon growth
efficiency and bacterial production rates, heterotrophic activity was estimated to average 5.4 μg-at. C l-1 d-1. The turn-over rate of DOC (average 114 μg-at. C l-1) due to bacterial consumption was estimated to be 0.048 d-1 during the period of study.
Accepted: 25 July 1998 相似文献
20.
Valdemaras Žiliukas Vida Žiliukienė Rimantas Repečka 《Central European Journal of Biology》2012,7(5):858-866
The aim of this study was to assess juvenile fish communities in terms of species composition, fish diversity and density in the littoral zone of the Kaunas reservoir before (in 1989–1990, period I) and after (in 1999–2000, period II, and in 2006–2007, period III) launching the Kruonis hydroelectric pumped plant (Kruonis HPP). During the whole research period, 20 fish species were caught. According to the frequency of occurrence, the three-spined stickleback Gasterosteus aculeatus, European perch Perca fluviatilis and roach Rutilus rutilus were regarded as constant species in all investigated periods. Significant differences were established in juvenile fish community density between period I and periods II and III, whereas species richness (S) and species diversity indices (H′, J′) did not change significantly. The density of the shoreline community in period III was more than two times lower than in period I, probably due to higher fluctuations in water level of the reservoir, resulting from the Kruonis HPP operation. 相似文献