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1.
Tetsu Hirata 《Ecological Research》1991,6(3):347-362
Community succession in the metabolism, biomass and maturity of sessile organisms on concrete plates immersed at depths of
1.0, 2.5, 4.0 and 5.5 m in Nabeta Bay, Shimoda, pacific coast of Japan, was investigated over a period of about 3 yr. Gross
primary production of the community (Pg) and community respiration (R) showed maxima at 10 and 13 months after immersion,
and then Pg decreased significantly at all depths, whereas R was reduced only at the lower two depths. A parameter of community
biomass, chlorophylla (Chl.a), showed a similar successional change to Pg. Five other parameters, i.e. dry mass (DM), ash dry mass (ADM), ash-free dry
mass (AFDM), organic carbon (C) and organic nitrogen (N) increased significantly throughout succession, at least at the uppermost
depth, but decreased significantly in the period 13–37 months after immersion at the lowest depth. Successional changes in
five indices reflecting community maturity, i.e. the ratios of estimated daily gross primary production/estimated daily respiration
(Pg/R), gross primary production/organic carbon (Pg/C), gross primary production/chlorophylla (Pg/Chl.a), organic carbon/organic nitrogen (C/N) and Margalef's pigment diversity (D430/D665), also differed among the depths, especially
at 37 months after immersion. Succession at the upper two depths appeared to progress toward a mature state, as opposed to
retrogression to an immature state at the lower two depths. This difference in successional changes in these 13 parameters
between depths agrees with the prediction of Margalef (1968) and Odum (1969), despite the tendency for Pg/R to be more heterotrophic
in an open system.
Contributions from the Shimoda Marine Research Center, No. 515. 相似文献
2.
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
3.
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
4.
土壤微生物是生态系统维持正常结构与功能的重要组成部分,为探究盐城滩涂典型湿地土壤微生物群落结构特征,以江苏盐城滩涂互花米草、藨草、盐地碱蓬、芦苇及淤泥质光滩5种典型群落为对象,采用16S rRNA高通量测序技术分析0—10 cm(表层)、10—30 cm(中层)、30—60 cm(深层)土壤微生物多样性及群落结构。结果表明:(1)几种植物群落间,土壤微生物群落结构差异较大,主要体现在细菌群落结构的差异性,古菌群落结构差异相对较小。光滩与植物群落间,在土壤细菌种类及相对丰度上差异相对较大,互花米草群落与本土植物群落间,在微生物群落的细菌种类组成上存在较大差异;藨草群落土壤表层微生物群落结构与互花米草群落相似,深层与盐地碱蓬、芦苇群落相似。(2)同一群落不同层次土壤微生物群落结构相似,差异小于不同群落间土壤微生物群落的结构差异性;不同群落对应层次间,表深层土壤中五种群落土壤微生物多样性存在显著差异,中层土壤中五种群落微生物多样性差异不显著。总体上,植物群落类型对土壤微生物群落结构的影响大于土壤深度;与本土植物群落相比,互花米草群落土壤主要优势门微生物种类差异较小,但部分优势门微生物相对丰度... 相似文献
5.
Benthos structure on tropical tidal flats of Australia 总被引:3,自引:0,他引:3
S. Dittmann 《Helgoland Marine Research》1995,49(1-4):539-551
General features of benthos communities of tropical tidal flats are defined from northeast Australia, based on surveys from
1988 to 1991 in Hinchinbrook Channel and in the Haughton River estuary. A zonation of benthic communities is described. Total
abundances for macrofauna averaged 31 individuals 200 cm−2, mesofauna (defined as infauna smaller than 0.5 mm and retained on a 0.25 mm sieve) averaged 16 individuals 10 cm−2 and meiofauna averaged 231 individuals 5 cm−2. The two study sites were similar in their abundance structures, but species due to a higher diversity of polychaeta in the
Channel (120 species, H′=3.80 vs. 29 species and H′=1.78 in the Haughton estuary). Species densities were comparable at both
sites and rather low (6 species 177 cm−2, 2–7 species 10 cm−2 and 5 meiobenthic Plathelminth species 5 cm−2). Over 50% of the species encountered were represented by less than three individuals. Deposit feeders, dominated the assemblages
both in terms of individuals as well as species numbers. Tropical tidal flats are compared with their temperate counterparts
and approaches for future research in tropical benthos communities are recommended. 相似文献
6.
Changwoo Ahn Patrick M. Gillevet Masoumeh Sikaroodi Kristin L. Wolf 《Wetlands Ecology and Management》2009,17(4):397-407
We studied redoximorphic features, field indicators and bacterial communities of soils in hummocks and hollows of a palustrine
forested wetland in Virginia. We hypothesized that presence of hydric soils, soil physicochemistry and soil bacterial community
structure would differ between hummocks and hollows. We fingerprinted soils collected from different microtopographic locations
using Length Heterogeneity Polymerase Chain Reaction (LH-PCR) to study their bacterial community structures. Two hummocks
had silty/sandy loam soils with mean chroma values of > 4, showing no indication of ‘hydric soils’ (i.e., wetland soils).
Two hollows, however, had clay loam soils with mean chroma values of 2 with gleying and redox concentrations observed, indicative
of seasonally inundated wetlands. The soils of hollows also had higher organic matter content and soil moisture compared to
the soils of hummocks (P < 0.05). Multidimensional scaling (MDS) and Analysis of similarity (ANOSIM) of the fingerprints revealed differences in soil
microbial community structures between hummocks and hollows (Global R = 0.30, P < 0.01). The diversity measures of the fingerprints (Shannon’s H′) were also different by microtopography with higher diversity
in hollows relative to hummocks (P < 0.05). LH-PCR proves to be a useful tool in examining bacterial community composition of wetland soils in this study. However,
cloning and sequencing of specific community LH-PCR profiles of interest is necessary to fully characterize the community
down to genus/species level. With species identities we should be able to not only better explain differences observed in
the community profiles, but study their relations to hydrologic and/or physicochemical conditions of wetlands. 相似文献
7.
Density and biomass of the larvae of a small, alien chironomid midge, Limnophyes minimus, whose parthenogenetic adult females do not feed, were quantified for ten major lowland plant communities at sub-Antarctic
Marion Island (46°52′S 37°51′E) and compared with the density and biomass of indigenous macro-invertebrates in the same communities.
An estimate of litter consumption by larvae of this midge was also made. L. minimus reached high densities in most of the plant communities sampled, with the highest density being recorded in the Cotula plumosa biotically influenced community (annual mean of 4,365 individuals m−2) and the lowest in the Crassula moschata salt spray community (annual mean of 41 individuals m−2). Estimates of litter ingestion indicated that L. minimus larvae are capable of consuming between 0.07 and 8.54 g(dry mass) m−2 per year, depending on the community. In some communities this litter consumption amounted to an order of magnitude more
than that consumed by Pringleophaga marioni (Lepidoptera, Tineidae). Although the larvae of this moth species are thought to represent the bottleneck to nutrient recycling
on the island, this study showed that midge larvae may also contribute substantially to this process. As a consequence, the
considerable changes that have been predicted to occur in Marion Island's terrestrial ecosystem as a consequence of enhanced
predation by mice on P. marioni larvae may be retarded or obscured by the contribution of the midge larvae to nutrient cycling. Hence, it is suggested that
greater attention be given to the small and inconspicuous elements of the alien sub-Antarctic faunas because such species
may have profound consequences for ecosystem functioning on these islands.
Received: 17 November 1997 / Accepted: 23 February 1998 相似文献
8.
Tropical zooplankton in the highly-enclosed lagoon of Taiaro Atoll (Tuamotu Archipelago, French Polynesia) 总被引:1,自引:0,他引:1
Nocturnal zooplankton assemblages around Taiaro Atoll were sampled over six nights during February 1994. Replicate zooplankton
samples were collected at windward and leeward locations in the enclosed lagoon and adjacent ocean with a metered net (85 cm
diameter, 500 μm mesh) towed for 15 min at 5 m depth. The zooplankton community in the lagoon was very different from that
in the ocean. Oceanic samples contained 50 mostly holoplanktonic taxa (diversity index, H′=2.62; evenness index, J′=0.67).
Lagoonal samples contained 19 mostly meroplanktonic taxa (H′=1.54, J′=0.52) with three taxa (decapod larvae; an ostracod,
Cypridina sp.; a copepod, Acartia fossae) contributing >90% of the individuals. Unlike the ocean, zooplankton distributions in the lagoon were not homogenous; instead
spatial patterns were apparently formed by the interaction between hydrodynamic processes and species-specific behaviour.
Accepted: 28 August 1997 相似文献
9.
This work constitutes the first floristic and ecological analysis of the phytoplankton community of a volcanic freshwater
lake in Deception Island (62°57′S, 60°38′W, South Shetland Islands, Antarctica). The main limnological features and phytoplankton
size fractions were analyzed. Samples were taken during the austral summer of 2002 at two opposite sites. According to ANOVA
results performed with abiotic variables, no significant differences between sites were found. The phytoplankton community
showed low algal species richness, with an important contribution of the tychoplanktonic taxa. In terms of species number,
Bacillariophyceae was the dominant class. Autotrophic picoplankton registered the highest densities from the second sampling
date onwards. Nanophytoplankton was represented by unidentified chrysophycean organisms, which showed different distribution
patterns between sites. The net phytoplankton abundance remained low during the sampling period and was strongly correlated
with chlorophyll a concentration. Both nutrient concentrations and chlorophyll a values indicated oligotrophic conditions. 相似文献
10.
Although combining datasets is often needed to unravel large-scale or long-term patterns in benthos ecology, this is frequently
hampered by differences in technical design of the individual studies. One element that often vary among macrobenthic studies
is the sieving procedure: sieving alive versus sieving after fixation. This study therefore aimed at the qualification and
quantification of the impact of sieving procedure, using a 1 mm mesh sized sieve, at three levels of ecological organisation:
(1) diversity, (2) species and taxon density, and (3) community structure. To include a maximum suite of macrobenthic species
and to evaluate the community-specific effects, the impact of sieving procedure was investigated within four widely spread
macrobenthos communities in the Belgian part of the North Sea. Sieving alive negatively impacted all tested diversity measures
(S, N1, N2, N∞, H′, ES
100 and J′): community-dependent relative losses of up to 35% were observed. However, most trends were ambiguous and statistically
non-significant. Community- and taxon-dependent impacts were detected at the level of density. Mainly polychaetes were found
to be negatively impacted by sieving alive (relative losses maximum 81%): especially small, interstitial polychaetes (e.g.
Hesionura elongata and Spio filicornis) tend to actively escape from the sieve (relative loss up to 100%). Next to size, also behaviour, the presence of head appendages,
the depth of the sampling stations and sampling season are believed to influence the sieving procedure impact. While detailed
community composition was impacted (ANOSIM dissimilarity: maximum 85%), no major impact on the differentiation between the
investigated communities was detected. The present study thus demonstrated that combining data, retrieved with a different
sieving procedure can be useful, but its reliability will mainly depend on the type of questions one wants to answer. In all
cases caution at all levels of ecological organisation is advised. 相似文献
11.
Microbial Community Structure and Density Under Different Tree Species in an Acid Forest Soil (Morvan, France) 总被引:2,自引:0,他引:2
Overexploitation of forests to increase wood production has led to the replacement of native forest by large areas of monospecific
tree plantations. In the present study, the effects of different monospecific tree cover plantations on density and composition
of the indigenous soil microbial community are described. The experimental site of “Breuil-Chenue” in the Morvan (France)
was the site of a comparison of a similar mineral soil under Norway spruce (Picea abies), Douglas fir (Pseudotuga menziesii), oak (Quercus sessiflora), and native forest [mixed stand dominated by oak and beech (Fagus sylvatica)]. Sampling was performed during winter (February) at three depths (0–5, 5–10, and 10–15 cm). Abundance of microorganisms
was estimated via microbial biomass measurements, using the fumigation–extraction method. The genetic structure of microbial
communities was investigated using the bacterial- and fungal-automated ribosomal intergenic spacer analysis (B-ARISA and F-ARISA,
respectively) DNA fingerprint. Only small differences in microbial biomass were observed between tree species, the highest
values being recorded under oak forest and the lowest under Douglas fir. B- and F-ARISA community profiles of the different
tree covers clustered separately, but noticeable similarities were observed for soils under Douglas fir and oak. A significant
stratification was revealed under each tree species by a decrease in microbial biomass with increasing depths and by distinct
microbial communities for each soil layer. Differences in density and community composition according to tree species and
depth were related to soil physicochemical characteristics and organic matter composition. 相似文献
12.
An experimental analysis of the relationship between species combination and community persistence 总被引:1,自引:0,他引:1
Among many stabilizing factors for community dynamics, nonlinear biological interactions such as type III functional response
have been widely considered to be major characteristics. However, most experimental biological communities employed so far
had quite simple structures. Therefore, the possibility that the conclusions in earlier studies were dependent on simple community
structure is undeniable. In this study, using a multiple-species experimental community, we evaluated which combinations of
component species and what kinds of interspecific interactions allow communities to persist and how these contribute to community
persistence. We conducted experimental communities using two species of beans, the adzuki bean (Vigna angularis) and the red kidney bean (Phaseolus vulgaris), two species of bean weevils, the Mexican bean weevil (Zabrotes subfasciatus, Coleoptera: Bruchidae) and adzuki bean weevil (Callosobruchus chinensis, Coleoptera: Bruchidae), and two species of parasitic wasp, Heterospilus prosopidis (Hymenoptera: Braconidae) and Anisopteromalus calandrae (Hymenoptera: Pteromalidae). The outcome of multiple-generation experimental communities was explained by the characteristics
of component species obtained from short-term experiments. In our two resources–two herbivores–one carnivore system, the strong
density-dependent attack ability of one parasitic wasp species (A. calandrae) led to the extinction of C. chinensis. On the other hand, the weak density-dependent attack ability of the other parasitic wasp species (H. prosopidis) led to system persistence. Our overall results show that, in a multiple-species community, the combination of species itself
is more important for community persistence than are the characteristics of the particular species.
Received: September 29, 1997 / Accepted: October 5, 1998 相似文献
13.
Biodiversity is quantified via richness (e.g., the number of species), evenness (the relative abundance distribution of those
species), or proportional diversity (a combination of richness and evenness, such as the Shannon index, H′). While empirical studies show no consistent relationship between these aspects of biodiversity within communities, the mechanisms
leading to inconsistent relationships have received little attention. Here, using common evening primrose (Oenothera biennis) and its associated arthropod community, we show that relationships between arthropod richness, evenness, and proportional
diversity are altered by plant genotypic richness. Arthropod richness increased with O. biennis genotypic richness due to an abundance-driven accumulation of species in response to greater plant biomass. Arthropod evenness
and proportional diversity decreased with plant genotypic richness due to a nonadditive increase in abundance of a dominant
arthropod, the generalist florivore/omnivore Plagiognathas politus (Miridae). The greater quantity of flowers and buds produced in polycultures—which resulted from positive complementarity
among O. biennis genotypes—increased the abundance of this dominant insect. Using choice bioassays, we show that floral quality did not change
in plant genotypic mixtures. These results elucidate mechanisms for how plant genotypic richness can modify relationships
between arthropod richness, evenness, and proportional diversity. More broadly, our results suggest that trophic interactions
may be a previously underappreciated factor controlling relationships between these different aspects of biodiversity. 相似文献
14.
Martin Hartmann Sangwon Lee Steven J. Hallam William W. Mohn 《Environmental microbiology》2009,11(12):3045-3062
Disturbances caused by timber harvesting have critical long‐term effects on the forest soil microbiota and alter fundamental ecosystem services provided by these communities. This study assessed the effects of organic matter removal and soil compaction on microbial community structures in different soil horizons 13 years after timber harvesting at the long‐term soil productivity site at Skulow Lake, British Columbia. A harvested stand was compared with an unmanaged forest stand. Ribosomal intergenic spacer profiles of bacteria, archaea and eukarya indicated significantly different community structures in the upper three soil horizons of the two stands, with differences decreasing with depth. Large‐scale sequencing of the ribosomal intergenic spacers coupled to small‐subunit ribosomal RNA genes allowed taxonomic identification of major microbial phylotypes affected by harvesting or varying among soil horizons. Actinobacteria and Gemmatimonadetes were the predominant phylotypes in the bacterial profiles, with the relative abundance of these groups highest in the unmanaged stand, particularly in the deeper soil horizons. Predominant eukaryal phylotypes were mainly assigned to known mycorrhizal and saprotrophic species of Basidiomycetes and Ascomycetes. Harvesting affected Basidiomycetes to a minor degree but had stronger effects on some Ascomycetes. Archaeal profiles had low diversity with only a few predominant crenarchaeal phylotypes whose abundance appeared to increase with depth. Detection of these effects 13 years after harvesting may indicate a long‐term change in processes mediated by the microbial community with important consequences for forest productivity. These effects warrant more comprehensive investigation of the effects of harvesting on the structure of forest soil microbial communities and the functional consequences. 相似文献
15.
Yosiaki Itô 《Ecological Research》2007,22(4):703-705
There are some recommendations for the use of species diversity indices in a paper recently published in this journal by M.
Ohsawa on the species richness and composition of weevils in five forest types in the middle region of Japan. Because several
factors, such as small sample size, calculation of Simpson’s diversity index by the use of the original equation of Simpson’s
measure of concentration D, and a weak point in the Shannon–Wiener diversity index H′, may have led to biased estimates, I recalculated these indices using combined species diversity values of the five forest
types. As the general tendencies of 1−D and H′ values calculated here were similar to those in Ohsawa’s paper, there is no need to propose any change to his view. However,
these recalculated diversity indices indicated that they are values which are more suitable for use. It should be noted that
the characteristics and weak point associated with the diversity indices need to be taken into account in future studies. 相似文献
16.
Ute Mühlenhardt-Siegel 《Helgoland Marine Research》1988,42(1):37-65
Macrobenthic fauna and sediment structure were studied at 6 stations from June 1979 to April 1981. The investigations were
carried out in the outer estuary of the River Elbe at depths of 15–38 m near a sewage sludge dumping site. The sediment near
this area consisted of a high portion of silt. Usually, very few species and small numbers of individuals were found near
that dumping ground. During summer 1980, a mass development ofAbra alba and several polychaete species caused an increase in species number which broke down during the following winter. The mass
development observed in the study area was apparently not directly caused by the sludge dumping itself, but reflects the natural
variability of the community structure. The number of species recorded was significantly correlated with a grain size fraction>31
μm, especially in summer. The seasonal and spatial fluctuation of the benthic community could be well documented by the abundance
per species (N/S index). The Shannon-Wiener-Index (H′) and eveness (J) were also useful indicators of community variability.
The log-normal distribution did not show the seasonal and the spatial differences of the stations. Possible reasons are discussed.
The biomass at the stations near the dumping area was less except during the mass development ofA. alba. The average individual weight (B/N) was shown to be a good indicator of population fluctuations; polychaete biomass was
positively correlated to a grain size fraction≦6 μm, that of molluscs to a grain size fraction>31 μm.
相似文献
17.
Are artificial reefs surrogates of natural habitats for corals and fish in Dubai,United Arab Emirates? 总被引:1,自引:0,他引:1
Artificial reefs are often promoted as mitigating human impacts in coastal ecosystems and enhancing fisheries; however, evidence
supporting their benefits is equivocal. Such structures must be compared with natural reefs in order to assess their performance,
but past comparisons typically examined artificial structures that were too small, or were immature, relative to the natural
reefs. We compared coral and fish communities on two large (>400,000 m3) and mature (>25 year) artificial reefs with six natural coral patches. Coral cover was higher on artificial reefs (50%)
than in natural habitats (31%), but natural coral patches contained higher species richness (29 vs. 20) and coral diversity
(H′ = 2.3 vs. 1.8). Multivariate analyses indicated strong differences between coral communities in natural and artificial habitats.
Fish communities were sampled seasonally for 1 year. Multivariate fish communities differed significantly among habitat types
in the summer and fall, but converged in the winter and spring. Univariate analysis indicated that species richness and abundance
were stable throughout the year on natural coral patches but increased significantly in the summer on artificial reefs compared
with the winter and spring, explaining the multivariate changes in community structure. The increased summer abundance on
artificial reefs was mainly due to adult immigration. Piscivores were much more abundant in the fall than in the winter or
spring on artificial reefs, but had low and stable abundance throughout the year in natural habitats. It is likely that the
decreased winter and spring abundance of fish on the artificial reefs resulted from both predation and emigration. These results
indicate that large artificial reefs can support diverse and abundant coral and fish communities. However, these communities
differ structurally and functionally from those in natural habitats, and they should not be considered as replacements for
natural coral and fish communities. 相似文献
18.
Inter-annual variations in zooplankton community structure in Prydz Bay were investigated using multivariate analysis based
on samples collected with a 330-μm mesh, 0.5-m2 Norpac net during the austral summer from 1999 to 2006. Two distinct communities, an oceanic and a neritic community, were
consistently identified in all surveys. Oceanic communities had higher diversity and were indicated by species such as Haloptilus ocellatus, Heterorhabdus austrinus, Thysanoessa macrura, Rhincalanus gigas, Scolecithricella minor and Oikopleura sp.. Neritic communities were indicated by Euphausia crystallorophias and Stephos longipes and were characterized by fewer but more abundant species. In 1999 and 2006, a transitional community was also distinguished near the continental shelf edge, where ice coverage was
more extensive than either the oceanic or neritic regions. Significant inter-annual variations in community structure (mainly
involving species abundance rather than species composition) were found in both oceanic and neritic communities, being more
obvious in the latter. The timing and amplitude of sea ice retreat (polynya appearance), and its effect on food availability,
had strong influences on zooplankton community structure. In oceanic communities during years with earlier ice retreat, the
extra time available for phytoplankton blooms to accumulate resulted in a higher proportion of large copepods (Calanoides acutus, Calanus propinquus, Metridia gerlachei) (especially the younger copepodites) in the zooplankton assemblage. In neritic communities, zooplankton such as the ice
krill E. crystallorophias, and large copepods (C. acutus, C. propinquus, M. gerlachei), also showed higher abundance and earlier developmental stages in years with larger polynya. On the other hand, in years
with later ice retreat, smaller polynya, and less time for phytoplankton blooms to form, the abundance of large copepods was
lower and older age classes were more common. 相似文献
19.
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
20.
于2012年7月至2013年4月调查了荣成靖海湾3个不同水深的刺参(Apostichopus japonicus)养殖池塘内大型底栖动物的构成,以了解不同水深对刺参养殖池塘环境条件的影响以及由此引起的大型底栖生物群落结构的改变。结果表明:3个不同水深梯度池塘(1#浅水位、2#正常水位和3#高水位)底部光照强度、叶绿素a(Chla)和总有机物(TOM)含量存在显著差异,各池塘水温差异不显著。光强、Chla和TOM含量在夏季、冬季和春季均表现为1#池塘显著高于3#池塘;秋季各池塘间光强和TOM含量差异不显著,Chla含量则表现为3#池塘显著高于1#池塘。各季节3个池塘间大型底栖动物在种类组成、丰度、生物量和多样性指数上均存在显著性差异。大型底栖动物丰度和生物量夏季均表现为1#池塘显著高于3#池塘,秋季和冬季则相反;春季1#池塘丰度显著高于3#池塘,生物量则差异不显著。这些差异主要与其各自优势种及其优势度指数大小有关。大型底栖动物多样性指数夏季和秋季均表现为1#池塘高于3#池塘,春季则相反,冬季各池塘间多样性指数差异不显著。单因子相似性分析(ANOSIM)表明,各季节3个池塘间大型底栖动物群落结构均存在显著差异,表明水深梯度对刺参养殖池塘大型底栖动物群落结构造成显著性影响。相似性百分比分析(SIMPER)显示,各季节对3个池塘间大型底栖动物群落差异起主要作用的物种为各个池塘的优势种。典范对应分析(CCA)表明,水深、Chla和TOM含量为影响大型底栖动物群落的主要环境因子。 相似文献