Temporal patterns in the macrobenthic communities of the Hawkesbury estuary, New South Wales

1987 ◽  
Vol 38 (5) ◽  
pp. 607
Author(s):  
AR Jones
Keyword(s):  
Community Composition ◽  
Temporal Patterns ◽  
Single Species ◽  
Species Number ◽  
Community Patterns ◽  
Low Salinity ◽  
Number Of Species ◽  
South Wales ◽  
Physicochemical Factors ◽  
Number Of Individuals

Temporal patterns in number of species, number of individual animals and community composition of the soft-sediment zoobenthos of the Hawkesbury estuary are described and related to physicochemical factors. Replicate grabs were taken at 3-month intervals over 3 years (1977-1979) from sites located in three zones: the lower, middle and upper reaches. The number of species and number of individuals showed significant seasonal and annual differences in all zones. However, the pattern of these differences varied among sites and seasonal differences were not repeatable over years. Similarly, differences in community composition as revealed by classification were not seasonal. In the middle and lower reaches, these differences were apparently caused by the over- riding influence of non-seasonal climatic events, i.e. a major flood in 1978 and a drought throughout 1979. In the first two sampling following the flood, sample values for the numbers of both species and individuals were usually lowest and community composition was distinct from pre-flood and drought times. During the drought, the number of species was usually high and community composition relatively distinct. Whereas the number of species and community composition groupings were both significantly related to river discharge, the number of individuals was significantly correlated with temperature. All community variables were sometimes significantly related to salinity. The identity of numerically dominant species, as determined by Fager rankings, varied among times in both the lower and middle reaches. However, the polychaete Nephtys australiensis and the bivalve mollusc Notospisula trigonella were highest ranked overall in both zones. Community patterns in the low-salinity upper reaches differed from those further downstream by showing little change in numbers of species and community composition following the flood. Only the number of species was significantly correlated with any of the measured physicochemical variables, this being partly due to an influx of species during the drought. Furthermore, the upstream community was always dominated by the polychaete Ceratonereis limnetica and was thus the only community that could be characterised by a single species.

Spatial patterns in the macrobenthic communities of the hawkesbury estuary, New South Wales

1986 ◽  
Vol 37 (4) ◽  
pp. 521 ◽  
Author(s):  
AR Jones ◽  
CJ Watson-Russell ◽  
A Murray
Keyword(s):  
Community Composition ◽  
Spatial Patterns ◽  
Species Number ◽  
Number Of Species ◽  
Physicochemical Changes ◽  
Biological Variables ◽  
South Wales ◽  
Physicochemical Factors ◽  
Highly Correlated ◽  
Number Of Individuals

Spatial patterns in the number of species, number of individual animals and community composition of the benthos of the Hawkesbury Estuary, N.S.W., are described and related to physicochemical factors. Replicate grabs were taken from deep and shallow sites located on transects across the estuary for each of five times at intervals of 3 months. The number of species and number of individuals always differed significantly along the estuary but the pattern of difference varied with both depth and time. Although a monotonic decline in the number of species along the estuary never occurred, the two most- seaward transects usually supported the most species and the three furthest-upstream transects the least. The number of species was usually more highly correlated with salinity than with sedimentary variables but salinity correlations were not always significant. The number of individuals was not related to any abiotic variable in a consistent way. Significant depth-related differences occurred only for the number of individuals although the pattern of difference varied among both transects and times. Sediment-associated differences also varied with transect and time. Where consistent differences occurred, highest species numbers were sometimes associated with sand and sometimes with coherent clay. Consequently the species-sediment relationship is not always a simple linear function of grain size and different aspects of sediment structure may be influential. Sediments with greater habitat heterogeneity sometimes supported more species and sometimes fewer species than more uniform sediments. Classification and ordination analyses revealed major patterns in community composition that were most closely related to salinity and minor patterns related to sediment grade. Community changes did not always correspond with physicochemical changes and hence the latter were not always good predictors of biological variables.

scholarly journals Komunitas Gastropoda Mangrove di Sungai Perpat dan Bunting, Kecamatan Belinyu, Kabupaten Bangka

2021 ◽  
Vol 6 (2) ◽  
pp. 85
Author(s):  
Eka Yuliawati ◽  
Budi Afriyansyah ◽  
Nova Mujiono
Keyword(s):  
Species Composition ◽  
Environmental Change ◽  
Dominant Species ◽  
Mangrove Ecosystem ◽  
Species Number ◽  
Mangrove Area ◽  
Number Of Species ◽  
Mangrove Ecosystems ◽  
Number Of Individuals

<strong>Mangrove gastropod community in Perpat and Bunting Rivers, Belinyu District, Bangka Regency</strong>. Perpat and Bunting in Bangka Regency have an adequate and natural mangrove ecosystems. However, studies on the structure of the gastropod community in this ecosystem is lacking. This study aimed to discover the structure of the gastropod community in the mangrove ecosystem. This study was carried out from October to November 2019 in riverine mangrove area located in Perpat and Bunting Rivers, District Belinyu, Bangka Regency. Samples were taken from 10 x 10 m plot from six observed stations. A total of 578 individuals of gastropoda were collected, comprised of seven families and 14 species. Number of species ranged from 4 to 9, while number of individuals ranged from 35 to 214. <em>Cerithidea quoyii</em> was a dominant species with 270 individuals (47%) and found in all stations. Gastropods community was in labile condition and prone to environmental change. Species composition of gastropods were similar in both rivers with nine identical species. However, epifaunal species were found separately from arboreal species

scholarly journals Sampling principles for biodiversity study

2013 ◽  
Author(s):  
Xubin Pan
Keyword(s):  
Mathematical Expectation ◽  
Specific Area ◽  
Species Number ◽  
Basic Principles ◽  
Number Of Species ◽  
Individual Number ◽  
Species Area ◽  
Biodiversity Study ◽  
Number Of Individuals ◽  
Total Species

Sampling is a fundamental tool in ecology and critical for biodiversity measurement. However, basic principles of biodiversity sampling have been overlooked for many years. In this paper, I proposed and explored five principles of sampling for a specific area and biodiversity study. The first principle of sampling, species increasing with area, is that the number of species increases with the area. The second principle of sampling, individuals increasing with area, is that the number of individuals increases with the area. The third principle of sampling, sum of species number, is that the sum of species number in one area and species number in another area is no less than the total species number in the two areas. The fourth principle of sampling, individual complement, is that the sum of the mathematical expectation of individual number of one or several species in the area a and that of the same one or several species in the area A-a is the total individual number N of the same one or several species in the total area A. The fifth principle of sampling, species-area theory, is that the sum of the mathematical expectation of number of species in the area a and that of number of species lost if area A-a is cleared is the total species number M in the total area A.

Bathymetric Distribution of Brittlestars (Ophiuroidea) Collected off the Northern Oregon Coast

1965 ◽  
Vol 22 (6) ◽  
pp. 1407-1424 ◽  
Author(s):  
Sergei Astrahantseff ◽  
Miles S. Alton
Keyword(s):  
Atomic Energy Commission ◽  
River Mouth ◽  
Benthic Fauna ◽  
Columbia River ◽  
Single Species ◽  
Species Number ◽  
Bathymetric Distribution ◽  
Number Of Species ◽  
Study Species ◽  
Benthic Zone

A cooperative study by the Bureau of Commercial Fisheries and the U. S. Atomic Energy Commission was undertaken to evaluate the composition of benthic fauna indigenous to waters adjacent to the Columbia River mouth. Standard stations were established by 25-fath intervals between 50 and 500 fath, and by 50-fath intervals from 500 to 1050 fath. Fifty- to 500-fath stations were monitored seasonally while sampling of deeper stations was generally restricted to spring and summer cruises.Twenty-four species of ophiuroids representing eight families and 14 genera were collected during this study. Species number varied by station ranging from one at 650 fath to a maximum of nine species at 300 fath.The number of species of ophiuroids by benthic zone showed a general increase with increasing depth. The total number of species collected by benthic zone was 4 from the sublittoral, 8 from the upper bathyal, 13 from the lower bathyal, and 15 from the abyssal. One, three, and eight species were confined to the outer sublittoral, lower bathyal, and abyssal, respectively.The highest availability of ophiuroids occurred between 150 and 250 fath and between 800 and 1050 fath. Lowest availability occurred at 125, 325, and 350 fath where few or no ophiuroids were observed. Larger catches of ophiuroids were estimated to contain from 500 to 2000 individuals. A single species, Ophiura sarsii, consistently dominated catches from 150 to 250 fath; while four species, Ophiocten pacificum, Ophiolimna bairdi, Ophiomusium lymani, and Ophiophthalmus normani, dominated catches between 800 and 1050 fath.The families Ophiuridae and Ophiacanthidae predominate in the study area. Together, they account for the majority of species collected which include the five most abundant species.The bathymetric distribution of ophiuroids from the Columbia River trackline illustrates a changing species composition with increasing depth, with the existence of both stenobathic and eurybathic species.

By-catch from Praen trawling in the Hawkesbury River, New South Wales: Species Composition, distribution and Abundance

1990 ◽  
Vol 41 (1) ◽  
pp. 13 ◽  
Author(s):  
CA Gray ◽  
VC McDonall ◽  
DD Reid
Keyword(s):  
Species Composition ◽  
New South ◽  
New South Wales ◽  
Spatial And Temporal Variability ◽  
Composition Distribution ◽  
Number Of Species ◽  
South Wales ◽  
By Catch ◽  
Autumn And Winter ◽  
Number Of Individuals

This study examined spatial and temporal variability in the composition, distribution and relative abundance of by-catch from prawn trawl sampling in the Hawkesbury River, New South Wales. It also determined whether there were differences in the fauna between sections of the river that are open and closed to prawn trawling. By-catch was sampled monthly between March 1986 and February 1988 in three areas along the river that differed in distance from the mouth of the estuary and in salinity. The total incidental catch comprised 75 species of fish, 13 species of crustaceans and 5 species of molluscs: 42 species were commercially and/or recreationally important. Classification and ordination analyses showed that the species composition of the by-catch differed between the area closest to the mouth of the estuary and that furthest upstream, and that this difference was relatively consistent throughout time. The number of species in the by-catch decreased with increasing distance upstream. Annual and seasonal changes in the number of species were similar in all areas along the river: more species were caught in 1987 than in 1986, and in autumn and winter each year. In contrast, the number of individuals caught differed among areas and these differences varied between years. Similarly, seasonal fluctuations in the numbers of individuals caught varied between years, but these variations were similar in all areas. In the area furthest upstream there were no apparent differences in the numbers of species and individuals caught by prawn trawl sampling in sections of the river open or closed to prawn trawling.

scholarly journals Temporal variations in community structure in and around intertidal barnacle (Chthamalus challengeri Hoek) patches on a plebby shore in Japan

1999 ◽  
Vol 59 (1) ◽  
pp. 43-53 ◽  
Author(s):  
M. APOLINÁRIO
Keyword(s):  
Community Structure ◽  
Intertidal Zone ◽  
Temporal Variations ◽  
The Other ◽  
Species Number ◽  
First Year ◽  
Number Of Species ◽  
Upper Intertidal ◽  
Chthamalus Challengeri ◽  
Number Of Individuals

The community structure in and around two barnacle (Chthamalus challengeri Hoek) patches (sites A and B) which extended from the middle to the upper intertidal zone on a pebbly shore in Magarisaki (Amakusa, Kyushu, Japan), was studied during summer and winter of 1995 and 1996. The results show a significant decrease in the proportion of substrate covered by barnacles from January 1995 to July 1996. The number of species, number of individuals, and biomass also decreased in the patch areas through time. There were significant differences between inside and outside the patches for percentage of substrate covered by barnacles, number of individuals, number of species, and biomass during the first year. Numbers of some gastropods were significantly higher in the barnacle patches, suggesting that the presence of barnacles create favorable microhabitat for the other taxa.

Comparing sampling strategies for surf-zone fish communities

2013 ◽  
Vol 64 (2) ◽  
pp. 102 ◽  
Author(s):  
Cassiano Monteiro-Neto ◽  
Luana Prestrelo
Keyword(s):  
Relative Abundance ◽  
Surf Zone ◽  
Sampling Strategy ◽  
Species Number ◽  
Sampling Strategies ◽  
Seasonal Component ◽  
Beach Seine ◽  
Number Of Species ◽  
Average Size ◽  
Number Of Individuals

Beach seining is used for capturing surf-zone fishes for scientific or fishery purposes. Sampling gear and different sampling approaches pose difficulties for comparative analyses. We compared parallel tows (PT) and beach hauls (BH) using the same beach seine, observing differences in species number (SPUA = number of species m–2), total and relative abundance (CPUA = number of individuals m–2) and average size. ANOVA and PERMANOVA showed that both the number of species and abundance were significantly different between sampling approaches and seasons, with higher values for BH. Most abundant Umbrina coroides showed significant interactions with higher CPUA for PT in summer and Diplodus argenteus for BH from winter to summer. Harengula clupeola and Trachinotus carolinus showed significant differences between sampling strategy with BH capturing more individuals. Trachinotus carolinus and Sardinella brasiliensis both showed differences between seasons with higher CPUA in the summer and autumn respectively. Results suggest that catch structure and composition differ between sampling strategies, but a seasonal component associated with recruitment of one or more species also influenced the catch. The PT appears to be more effective but time consuming. The BH may be an alternative method, but results may not be comparable.

An island biogeography model for beta diversity and endemism: The roles of speciation, extinction and dispersal

2015 ◽  
Vol 08 (01) ◽  
pp. 1550011 ◽  
Author(s):  
Youhua Chen
Keyword(s):  
Numerical Simulation ◽  
Community Composition ◽  
Beta Diversity ◽  
Island Biogeography ◽  
Positive Relationship ◽  
Community Patterns ◽  
Speciation Rate ◽  
Immigration Rate ◽  
Extinction Rates

A community composition island biogeography model was developed to explain and predict two community patterns (beta diversity and endemism) with the consideration of speciation, extinction and dispersal processes. Results showed that rate of speciation is positively and linearly associated with beta diversity and endemism, that is, increasing species rates typically could increase the percentage of both endemism and beta diversity. The influences of immigration and extinction rates on beta diversity and endemism are nonlinear, but with numerical simulation, I could observe that increasing extinction rates would lead to decreasing percentage of endemism and beta diversity. The role of immigration rate is very similar to that of speciation rate, having a positive relationship with beta diversity and endemism. Finally, I found that beta diversity is closely related to the percentage of endemism. The slope of this positive relationship is determined jointly by different combinations of speciation, extinction and immigration rates.

Use of stereo baited remote underwater video systems to estimate the presence and size of white sharks (Carcharodon carcharias)

2017 ◽  
Vol 68 (7) ◽  
pp. 1391 ◽  
Author(s):  
D. Harasti ◽  
K. A. Lee ◽  
R. Laird ◽  
R. Bradford ◽  
B. Bruce
Keyword(s):  
Relative Abundance ◽  
Fish Assemblages ◽  
New South ◽  
Underwater Video ◽  
Carcharodon Carcharias ◽  
South Wales ◽  
Video Systems ◽  
Near Shore ◽  
Number Of Individuals ◽  
Non Destructive

Stereo baited remote underwater video systems (stereo-BRUVs) are commonly used to assess fish assemblages and, more recently, to record the localised abundance and size of sharks. The present study investigated the occurrence and size of white sharks (Carcharodon carcharias) in the near-shore environment off Bennett’s Beach, part of a known nursery area for the species in central New South Wales, Australia. Six stereo-BRUV units were deployed approximately fortnightly between August and December 2015 for periods of 5h in depths of 7–14m. Stereo-BRUVs successfully recorded 34 separate sightings of 22 individual white sharks. The highest number of individuals detected during a single day survey was eight. All C. carcharias observed on stereo-BRUVs were juveniles ranging in size from 1.50 to 2.46-m total length (mean±s.e., 1.91±0.05m; n=22). The time to first appearance ranged from 15 to 299min (mean±s.e., 148±15min). This study demonstrates that the use of stereo-BRUVs is a viable, non-destructive method to obtain estimates of the size and presence of white sharks, and may be useful in estimating relative abundance in near-shore environments where white sharks are known to frequent.

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