Reply to the comment by Crook and Koster (2006) 'Temporal change in fish assemblages in the lower Goulburn River, south-eastern Australia'

2006 ◽  
Vol 57 (3) ◽  
pp. 309
Author(s):  
Carmel A. Pollino ◽  
Pat Feehan ◽  
Michael R. Grace ◽  
Barry T. Hart
Keyword(s):  
Multivariate Statistics ◽  
Fish Assemblages ◽  
Temporal Change ◽  
Spatial Scales ◽  
Fish Communities ◽  
Data Sets ◽  
Catchment Scale ◽  
Eastern Australia ◽  
Spatial Differences ◽  
The Stability

In an earlier paper, multivariate statistics were used on historic fisheries data sets to show spatial differences between fish communities in the Goulburn Catchment (Victoria, Australia). In this reply paper, some further statistical analyses are presented to provide evidence for the assertion that fish communities at each site were stable over the temporal scale of the data was valid. Indeed, evidence for the stabilisation and persistence of fish communities after a major disturbance has also been recognised in other studies. Furthermore, in making judgements about the stability and persistence of fish communities, the scale of a study is an important factor, with patterns at the catchment scale often not being the same as those at smaller spatial scales.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Fish Assemblage ◽  
Human Disturbance ◽  
Agricultural Land ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Relative Importance ◽  
Land Uses ◽  
Catchment Scale ◽  
Assemblage Composition ◽  
Local Factors

<em>Abstract.</em>—We analyzed data from 287 streams in Wisconsin and northern Michigan to evaluate the relative effects of human disturbance levels on the influence of catchment, network riparian, reach riparian, and instream variables on fish assemblages. The streams were divided into high, medium, and low human disturbance groups based on catchment and network riparian urban and agricultural land uses. We used canonical correspondence analyses to evaluate relations among variables at the four spatial scales and fish assemblage composition, abundance, and presence/absence and to partition the relative importance of spatial scales. Catchment and network riparian land uses were among the dominant variables correlated with fish for high disturbance catchments but not for low disturbance catchments. The variations in fish assemblage composition, abundance, and presence/absence explained by catchment factors were substantially higher for high than for low disturbance catchments, although the variations explained by network riparian factors and reach riparian land uses were similar among disturbance levels. In contrast, the variations in fish variables explained by instream factors and the interaction of the four spatial scale environmental factors were considerably lower for high disturbance than for low disturbance catchments. We concluded that in largely undisturbed catchments, fish assemblages were predominantly influenced by local factors, but as disturbance increased in catchments and riparian areas, the relative importance of local factors declined and that of catchment increased. Hence, instream and riparian habitat improvements would be most effective in catchments that are largely undisturbed and catchment scale land-use management would be more effective for improving stream quality in degraded catchments.

scholarly journals Seascape connectivity exerts differing effects for fish assemblages in distinct habitats of the surf zones of ocean beaches

2020 ◽  
Vol 77 (3) ◽  
pp. 1033-1042
Author(s):  
Jesse D Mosman ◽  
Christopher J Henderson ◽  
Andrew D Olds ◽  
Ben L Gilby ◽  
Thomas A Schlacher
Keyword(s):  
Species Richness ◽  
Indicator Species ◽  
Surf Zone ◽  
Fish Assemblages ◽  
Spatial Configuration ◽  
Spatial Scales ◽  
Coastal Habitat ◽  
Rocky Reefs ◽  
Eastern Australia ◽  
Management Approaches

Abstract Animals move throughout coastal seascapes to disperse, feed, and spawn, including the surf zones of ocean beaches. Yet, the influences of seascape context on surf-zone fish are largely unquantified. We sampled surf-zone fish assemblages with baited remote underwater video deployments at 25 beaches across 50 km of coastline in eastern Australia to determine if variation in the spatial configuration of broader coastal seascapes shapes fish assemblages in different surf-zone habitats. We show that surf zones are not homogenous fish habitats, with offshore bars and nearshore troughs having distinct fish assemblages, shaped by different environmental variables. Fish assemblages of offshore bars were characterized by greater species richness and a higher abundance of indicator species (as identified by Dufrene–Legendre indicator species analysis) when close to rocky reefs and estuaries. In contrast, fish assemblages of nearshore troughs were characterized by greater species richness and a higher abundance of indicator species when far from estuaries, and off wider beaches. Our results highlight the importance of seascape connectivity in structuring surf-zone fish assemblages. Consequently, management approaches need to more thoroughly quantify the effects of seascape connectivity over smaller spatial scales and consider surf zones as key components of broader coastal habitat mosaics.

scholarly journals Mesophotic fish communities of the ancient coastline in Western Australia

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250427
Author(s):  
Leanne M. Currey-Randall ◽  
Ronen Galaiduk ◽  
Marcus Stowar ◽  
Brigit I. Vaughan ◽  
Karen J. Miller
Keyword(s):  
Species Richness ◽  
Western Australia ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Habitat Type ◽  
Fish Communities ◽  
Fish Diversity ◽  
North West ◽  
Fish Biodiversity ◽  
Marine Diversity

Marine diversity across the Australian continental shelf is shaped by characteristic benthic habitats which are determined by geomorphic features such as paleoshorelines. In north-western Australia there has been little attention on the fish communities that inhabit an ancient coastline at ~125 m depth (the designated AC125), which is specified as a key ecological feature (KEF) of the region and is thought to comprise hard substrate and support enhanced diversity. We investigated drivers of fish species richness and assemblage composition spanning six degrees of latitude along sections of the ancient coastline, categorised as ‘on’ and ‘off’ the AC125 based on depth, across a range of habitats and seafloor complexity (~60–180 m depth). While some surveyed sections of the AC125 had hard bottom substrate and supported enhanced fish diversity, including over half of the total species observed, species richness and abundance overall were not greater on the AC125 than immediately adjacent to the AC125. Instead, depth, seafloor complexity and habitat type explained patterns in richness and abundance, and structured fish assemblages at both local and broad spatial scales. Fewer fishes were associated with deep sites characterized by negligible complexity and soft-bottom habitats, in contrast to shallower depths that featured benthic biota and pockets of complex substrate. Drivers of abundance of common species were species-specific and primarily related to sampling Areas, depth and substrate. Fishes of the ancient coastline and adjacent habitats are representative of mesophotic fish communities of the region, included species important to fisheries and conservation, and several species were observed deeper than their currently known distribution. This study provides the first assessment of fish biodiversity associated with an ancient coastline feature, improving our understanding of the function it plays in regional spatial patterns in abundance of mesophotic fishes. Management decisions that incorporate the broader variety of depths and habitats surrounding the designated AC125 could enhance the ecological role of this KEF, contributing to effective conservation of fish biodiversity on Australia’s north west shelf.

scholarly journals Influences of Multiscale Land Cover Characteristics and Specific Conductivity on Fish Assemblages in the Nolichucky River Watershed, Tennessee

2017 ◽  
Author(s):  
Hayley S. Gotwald ◽  
J. Brian Alford
Keyword(s):  
Land Use ◽  
Fish Species ◽  
Fish Assemblage ◽  
Forest Cover ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Specific Conductivity ◽  
Fish Assemblage Structure ◽  
Catchment Scale ◽  
River Watershed

We evaluated the potential of using fish species and functional traits as indicators of land use impacts to fish assemblages. We used environmental data collected at multiple spatial scales (local, reach, and upstream catchment) for 19 tributary and main stem sites in the Nolichucky River watershed in Tennessee. Canonical correspondence analyses showed that temperature, elevation, specific conductivity, sediment yield, impervious surfaces, and row crop cover at the catchment scale were strongly associated with fish assemblage structure, as well as forest cover from all three spatial scales. Blocked indicator species analysis, with stream size as the block, showed that significantly strong indicators of the least-impacted riparian land use condition (&ge;60% forest cover) were Saffron Shiner (Notropis rubricroceus), Rainbow Trout (Oncorhyncus mykiss), Longnose Dace (Rhynichthys cataractae), Creek Chub (Semotilus atromaculatus), and Mottled Sculpin (Cottus bairdi). Traits indicative of the least-impacted sites were the herbivorous trophic guild, mean female age-at-maturity, longevity, rock-gravel spawners, montane geology and pelagic swimmers. Specific conductivity was strongly related to multiple catchment-scale land use variables, and was a strong local-scale influence on fish assemblage structure. Our results show promise for using a relatively common but endemic southern Appalachian fish species, the Saffron Shiner, as an indicator for land-use related impacts to these streams.

Allele frequency stability in large, wild exploited populations over multiple generations: insights from Alaska sockeye salmon (Oncorhynchus nerka)

2012 ◽  
Vol 69 (5) ◽  
pp. 916-929 ◽  
Author(s):  
Daniel Gomez-Uchida ◽  
James E. Seeb ◽  
Christopher Habicht ◽  
Lisa W. Seeb
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Temporal Changes ◽  
Allele Frequencies ◽  
Annual Number ◽  
Data Sets ◽  
Nucleotide Polymorphisms ◽  
Snp Data ◽  
Spatial Differences ◽  
The Stability

We genotyped nuclear and mitochondrial single nucleotide polymorphisms (SNPs) in six paired archived and contemporary collections of Alaskan sockeye salmon ( Oncorhynchus nerka ) to evaluate the stability of allele frequencies over 25–42 years (4.9–8.4 generations). First, our results show that temporal changes were dramatically (between 40- and 250-fold) smaller than spatial differences in allele frequencies when based on nuclear SNPs. Second, the magnitude of temporal change was consistent with a model of genetic drift: (i) SNPs with high levels of differentiation (large θ) and candidates for diversifying selection were not more likely to show significant temporal changes than small-θ SNPs; and (ii) the fraction of single-locus significant tests was consistent with theoretical predictions relating sample size and the annual number of breeders (Nb). Third, estimates of Nb were bound by infinitely large upper 95% confidence intervals, except for one paired collection with unique life-history attributes of both a smoltification phase and generation time shorter than the other paired collections. Use of multigenerational SNP data sets seems a safe practice in management of Alaska sockeye salmon that could be extended to other large, wild aquatic populations.

Large-scale patterns in species richness and composition of temperate riverine fish communities, south-eastern Australia

2000 ◽  
Vol 51 (2) ◽  
pp. 165 ◽  
Author(s):  
Peter C. Gehrke ◽  
John H. Harris
Keyword(s):  
Species Richness ◽  
Large Scale ◽  
Fish Communities ◽  
Fish Fauna ◽  
South Coast ◽  
North Coast ◽  
Large Spatial Scale ◽  
River Types ◽  
Eastern Australia ◽  
Riverine Fish

Riverine fish in New South Wales were studied to examine longitudinal trends in species richness and to identify fish communities on a large spatial scale. Five replicate rivers of four types (montane, slopes, regulated lowland and unregulated lowland) were selected from North Coast, South Coast, Murray and Darling regions. Fishwere sampled during summer and winter in two consecutive years with standardized gear that maximized the range of species caught. The composition of fish communities varied among regions and river types, with little temporal variation. Distinct regional communities converged in montane reaches and diverged downstream. The fish fauna can be classified into North Coast, South Coast, Murray and Darling communities, with a distinct montane community at high elevations irrespective of the drainage division. Species richness increased downstream in both North Coast and South Coast regions by both replacement and the addition of new species. In contrast, species richness in the Darling and Murray regions reached a maximum in the slopes reaches and then declined, reflecting a loss of species in lowland reaches. The small number of species is typical of the freshwater fish faunas of similar climatic regions world-wide. Fish communities identified in this study form logical entities for fisheries management consistent with the ecosystem-focused, catchment-based approach to river management and water reform being adopted in Australia.

scholarly journals Evaluating irrigated rice yields in Japan within the Climate Zonation Scheme of the Global Yield Gap Atlas

2021 ◽  
pp. 1-12
Author(s):  
S. Ishikawa ◽  
T. Nakashima ◽  
T. Iizumi ◽  
M. C. Hare
Keyword(s):  
Production Capacity ◽  
Aridity Index ◽  
Data Sets ◽  
Yield Gap ◽  
Yield Data ◽  
Irrigated Rice ◽  
Rice Yields ◽  
The Stability ◽  
Temperature Seasonality ◽  
Government Statistics

Abstract The Global Yield Gap Atlas (GYGA) is an international project that addresses global food production capacity in the form of yield gaps (Yg). The GYGA project is unique in employing its original Climate Zonation Scheme (CZS) composed of three indexed factors, i.e. Growing Degree Days (GDD) related to temperature, Aridity Index (AI) related to available water and Temperature Seasonality (TS) related to annual temperature range, creating 300 Climate Zones (CZs) theoretically across the globe. In the present study, the GYGA CZs were identified for Japan on a municipality basis and analysis of variance (ANOVA) was performed on irrigated rice yield data sets, equating to actual yields (Ya) in the GYGA context, from long-term government statistics. The ANOVA was conducted for the data sets over two decades between 1994 and 2016 by assigning the GDD score of 6 levels and the TS score of 2 levels as fixed factors. Significant interactions with respect to Ya were observed between GDD score and TS score for 13 years out of 21 years implying the existence of favourable combinations of the GDD score and the TS score for rice cultivation. The implication was also supported by the observation with Yg. The lower values of coefficient of variance obtained from the CZs characterized by medium GDD scores indicated the stability over time of rice yields in these areas. These findings suggest a possibility that the GYGA-CZS can be recognized as a tool suitable to identify favourable CZs for growing crops.

A Statistical Test for the Stability of Covariance Structure

2013 ◽  
Vol 63 (2) ◽  
Author(s):  
Nur Syahidah Yusoff ◽  
Maman Abdurachman Djauhari
Keyword(s):  
Covariance Matrix ◽  
Complex Structure ◽  
Covariance Structure ◽  
Statistical Test ◽  
Dispersion Measure ◽  
Data Sets ◽  
Scalar Representation ◽  
Multivariate Dispersion ◽  
Sample Covariance ◽  
The Stability

The stability of covariance matrix is a major issue in multivariate analysis. As can be seen in the literature, the most popular and widely used tests are Box M-test and Jennrich J-test introduced by Box in 1949 and Jennrich in 1970, respectively. These tests involve determinant of sample covariance matrix as multivariate dispersion measure. Since it is only a scalar representation of a complex structure, it cannot represent the whole structure. On the other hand, they are quite cumbersome to compute when the data sets are of high dimension since they do not only involve the computation of determinant of covariance matrix but also the inversion of a matrix. This motivates us to propose a new statistical test which is computationally more efficient and, if it is used simultaneously with M-test or J-test, we will have a better understanding about the stability of covariance structure. An example will be presented to illustrate its advantage

scholarly journals CLASSIC: a semi-distributed rainfall-runoff modelling system

2007 ◽  
Vol 11 (1) ◽  
pp. 516-531 ◽  
Author(s):  
S. M. Crooks ◽  
P. S. Naden
Keyword(s):  
Spatial Scales ◽  
Digital Terrain Model ◽  
Flood Frequency ◽  
Data Sets ◽  
Rainfall Runoff ◽  
Terrain Model ◽  
Flow Duration Curves ◽  
Rainfall Runoff Model ◽  
The Uk ◽  
Modelling System

Abstract. This paper describes the development of a semi-distributed conceptual rainfall–runoff model, originally formulated to simulate impacts of climate and land-use change on flood frequency. The model has component modules for soil moisture balance, drainage response and channel routing and is grid-based to allow direct incorporation of GIS- and Digital Terrain Model (DTM)-derived data sets into the initialisation of parameter values. Catchment runoff is derived from the aggregation of components of flow from the drainage module within each grid square and from total routed flow from all grid squares. Calibration is performed sequentially for the three modules using different objective functions for each stage. A key principle of the modelling system is the concept of nested calibration, which ensures that all flows simulated for points within a large catchment are spatially consistent. The modelling system is robust and has been applied successfully at different spatial scales to three large catchments in the UK, including comparison of observed and modelled flood frequency and flow duration curves, simulation of flows for uncalibrated catchments and identification of components of flow within a modelled hydrograph. The role of such a model in integrated catchment studies is outlined.

Controlled Freezing of Nonideal Solutions With Application to Cryosurgical Processes

1991 ◽  
Vol 113 (4) ◽  
pp. 430-437 ◽  
Author(s):  
H. M. Budman ◽  
J. Dayan ◽  
A. Shitzer
Keyword(s):  
Cooling Rate ◽  
Freezing Process ◽  
Data Sets ◽  
Tracking Accuracy ◽  
Loop Control ◽  
Set Point ◽  
New Device ◽  
Loop Control System ◽  
The Stability ◽  
Controlled Freezing

Success of a cryosurgical procedure, i.e., maximal cell destruction, requires that the cooling rate be controlled during the freezing process. Standard cryosurgical devices are not usually designed to perform the required controlled process. In this study, a new cryosurgical device was developed which facilitates the achievement of a specified cooling rate during freezing by accurately controlling the probe temperature variation with time. The new device has been experimentally tested by applying it to an aqueous solution of mashed potatoes. The temperature field in the freezing medium, whose thermal properties are similar to those of biological tissue, was measured. The cryoprobe temperature was controlled according to a desired time varying profile which was assumed to maximize necrosis. The tracking accuracy and the stability of the closed loop control system were investigated. It was found that for most of the time the tracking accuracy was excellent and the error between the measured probe temperature and the desired set point is within ±0.4°C. However, noticeable deviations from the set point occurred due to the supercooling phenomenon or due to the instability of the liquid nitrogen boiling regime in the cryoprobe. The experimental results were compared to those obtained by a finite elements program and very good agreement was obtained. The deviation between the two data sets seems to be mainly due to errors in positioning of the thermocouple junctions in the medium.

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