Latitude, depth and environmental variables influence deepwater fish assemblages off Western Australia

2021 ◽  
Vol 539 ◽  
pp. 151539
Author(s):  
Claire M. Wellington ◽  
Euan S. Harvey ◽  
Corey B. Wakefield ◽  
Dave Abdo ◽  
Stephen J. Newman
Keyword(s):  
Western Australia ◽  
Environmental Variables ◽  
Fish Assemblages

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Land Cover ◽  
Ictalurus Punctatus ◽  
Environmental Variables ◽  
Agricultural Land ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Species Abundance ◽  
Ecological Condition ◽  
Basin Scale ◽  
Assemblage Metrics

<em>Abstract.</em>—We analyzed data from 38 sites on 31 large rivers in Wisconsin to characterize the influence of environmental variables at the basin, reach, and site scales on fish assemblages. Electrofishing and site habitat data were collected for a distance of 1.6 km per site. Environmental variables included conductivity, substrate, and fish cover at the site scale; distance to impoundments, dams, and length of riverine habitat at the reach scale; and land cover, climate, and geology at the basin scale. Of the 77 fish species found, 39 occurred in more than 10% of the sites and were retained for analyses of fish abundance and biomass. Redundancy analysis (RDA) was used to relate species abundance, biomass, and 16 assemblage metrics to environmental variables at the three spatial scales. The site and basin scales defined fishes along a gradient from high conductivity, fine substrate, and agricultural land cover to low conductivity, rocky substrate, and forested land cover. For abundance and biomass, the strongest assemblage pattern contrasted northern hog sucker <em>Hypentelium nigricans</em>, blackside darter <em>Percina maculata</em>, and logperch <em>P. caprodes </em>with common carp <em>Cyprinus carpio</em>, channel catfish <em>Ictalurus punctatus</em>, and sauger <em>Sander canadensis</em>. The <em>H. nigricans </em>group, along with high values of index of biotic integrity and some assemblage metrics (percent lithophilic spawners, percent round-bodied suckers), corresponded with the forested end of the ecological gradient, whereas the <em>C. carpio </em>group and percent anomalies corresponded with the agricultural end. Natural environmental conditions, including bedrock geology type, bedrock depth, surficial geology texture, basin area, and precipitation, also influenced the fish assemblage. Partial RDA procedures partitioned the explained variation among spatial scales and their interactions. We found that widespread land cover alterations at the basin scale were most strongly related to fish assemblages across our study area. Understanding the influence of environmental variables among multiple spatial scales on fish assemblages can improve our ability to assess the ecological condition of large river systems and subsequently target the appropriate scale for management or restoration efforts.

A Quantitative Study of Soil-Plant Relations in the Eastern Goldfields of Western Australia.

1998 ◽  
Vol 20 (1) ◽  
pp. 119 ◽  
Author(s):  
B Fergusson ◽  
AJ Graham
Keyword(s):  
Cluster Analysis ◽  
Multivariate Analysis ◽  
Plant Community ◽  
Plant Communities ◽  
Western Australia ◽  
Environmental Variables ◽  
Function Analysis ◽  
Field Site ◽  
Disturbed Areas ◽  
Exchangeable Ca

The soil and plants at a 27.4 ha field site near Kalgoorlie, Western Australia, were surveyed and analysed with multivariate statistics. Cluster analysis identified four distinct plant communities at the study site. These were: Acacia acuminata shrubland Eucalyptus gvfithsii woodland Eucalyptus salrnonophloia woodland 'Ground Covers' - areas characterised by the presence of generalist herbs, low shrubs and weeds, and the absence of dominant upper storey species. Discriminant function analysis identified site elevation and soil exchangeable Ca as the primary environmental discriminants between the plant communities. Using these two variables, sample points were classified into one of the four plant communities. The two methods of classification matched well, with classification based on the two environmental variables providing an indication of which plant community would be most likely to establish in disturbed areas. This type of information can be important to revegetation programs in the region, guiding the use of appropriate plant species under different rehabilitation conditions. Key wcrds: environmental variables, plant communities, multivariate analysis, classification, revegetation

Role of environmental and spatial processes structuring fish assemblages in streams of the eastern Amazon

2018 ◽  
Vol 69 (2) ◽  
pp. 243 ◽  
Author(s):  
N. L. Benone ◽  
R. Ligeiro ◽  
L. Juen ◽  
L. F. A. Montag
Keyword(s):  
Environmental Factors ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Flood Plain ◽  
Habitat Isolation ◽  
Flood Plains ◽  
Β Diversity ◽  
Flood Period ◽  
Stream Fish Assemblages ◽  
Stream Biota

Considering the increasing importance of analysing spatial structure in ecological studies, the aims of the present study were to test whether fluvial distances and environmental factors are important drivers of the β-diversity of stream fish assemblages, and whether β-diversity is different in distinct hydrological periods. Specimens were sampled at 33 stream sites in the eastern Amazon. Eight environmental variables were measured at each site and fluvial distances between pairs of stream sites were determined. Environmental variables were the main factors structuring fish assemblages in both periods. However, fluvial distances were important only during the flood period. This can be related to the formation of extensive flood plains in this period, which increases connectivity between streams, breaking habitat isolation and increasing the regional signal for fish species. The higher correlation of β-diversity with environmental variables during the flood period may be related to decreased dispersal limitations and intermediate dispersal. Finally, β-diversity was higher during the flood period, highlighting the importance of the heterogeneity of the flood plain to stream biota. The results of the present study indicate that spatial and environmental factors play complementary roles in structuring fish assemblages in Amazon streams, and that β-diversity was affected by changes in the habitat connectivity experienced in different hydrological periods.

scholarly journals The influence of depth on the Mediterranean reef fish assemblage revealed by the new video on underwater scooter method

2020 ◽  
Vol 61 (2) ◽  
pp. 145-162
Author(s):  
Igor Glavičić ◽  
Marcelo Kovačić ◽  
Dejan Paliska ◽  
Dani Laslo
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Average Density ◽  
Depth Range ◽  
Fish Assemblage Structure ◽  
Visual Census ◽  
Reef Fish Assemblage ◽  
Significant Difference

The new video on underwater scooter method in combination with rebreather diving techniques was introduced and applied for visual census of fish assemblages. The presently applied method facilitates deeper visual census studies below 40 m, where they have rarely been done before due to the increasing research challenges with depth. The video on underwater scooter method is also expected to be less disturbing and faster compared to swimming divers. The method was applied in visual census study of fish assemblages from 8 to 50 m depth conducted at two locations in the east Adriatic using 102 video transects. The environmental variables contributing to the variation of the reef fish community in the depth range of the infralittoral and upper circalittoral bottoms were also recorded. Thirty-one fish species were recorded on transects and 10.3% of all individuals were not identified to the species level. The average density on transects was 0.8 individuals/m², with C. chromis, C. julis and G. auratus being both the most abundant and the most frequent species. Three environmental variables, depth, bottom with zoocover and eastern orientation of the coast, were identified as highly significant for species occurrence. Abundance and species richness of fish assemblages showed no significant variation with depths, inclinations, orientations and sites. A significant difference in the fish assemblage structure was found among orientations, depths and inclinations with the gradient change of species composition with increasing depth and with increasing inclination.

scholarly journals Influence of urbanization on stream fish assemblages in three microbasins in the Upper Paraná River Basin

2023 ◽  
Vol 83 ◽  
Author(s):  
F. S. Ferreira ◽  
J. C. J. Solórzano ◽  
Y. R. Súarez
Keyword(s):  
Environmental Variables ◽  
Fish Assemblages ◽  
Water Velocity ◽  
Direct Effects ◽  
Environmental Filters ◽  
Urbanization Level ◽  
Upper Paraná River ◽  
Upper Paraná River Basin ◽  
Environmental Integrity ◽  
Stream Fish Assemblages

Abstract The colonization pattern of fish assemblages in streams is often studied in the context of environmental filters. On the other hand, when fish assemblages are subjected to anthropogenic effects, variables associated with environmental quality assume more importance. Therefore, this work evaluated the richness and composition of fish from streams sampled at different urbanization levels, aiming to determine any direct effects on the structure of fish assemblages. To accomplish this, samples were collected from 2003 to 2011 at 31 sites distributed among 3 microbasins in the Rio Ivinhema Basin, Alto Rio Paraná. Based on environmental variables, physicochemical of the water and analysis of the use and occupation of the soil, the microbasins were classified into different urbanization levels (low, medium and high). A total of 4,320 individuals were sampled, out of which 57 fish species were recorded. Sampled sites with medium urbanization level presented higher richness compared to sampled sites with high urbanization level which presented lower richness. Species richness in these sites was explained mainly by water temperature and water velocity. Results confirmed that urbanization does directly affect environmental integrity, which, in turn, can lead to the homogenization of stream assemblages.

scholarly journals Fish complementarity is associated to forests in Amazonian streams

2015 ◽  
Vol 13 (3) ◽  
pp. 579-590 ◽  
Author(s):  
Carolina Rodrigues Bordignon ◽  
Lilian Casatti ◽  
María Angélica Pérez-Mayorga ◽  
Fabrício Barreto Teresa ◽  
Gabriel Lourenço Brejão
Keyword(s):  
Habitat Use ◽  
Functional Traits ◽  
Fish Species ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
Functional Structure ◽  
Structure Of Communities ◽  
Net Relatedness Index ◽  
Functional Homogenization

The functional structure of communities is commonly measured by the variability in functional traits, which may demonstrate complementarity or redundancy patterns. In this study, we tested the influence of environmental variables on the functional structure of fish assemblages in Amazonian streams within a deforestation gradient. We calculated six ecomorphological traits related to habitat use from each fish species, and used them to calculate the net relatedness index (NRI) and the nearest taxon index (NTI). The set of species that used the habitat differently (complementary or overdispersed assemblages) occurred in sites with a greater proportion of forests. The set of species that used the habitat in a similar way (redundant or clustered assemblages) occurred in sites with a greater proportion of grasses in the stream banks. Therefore, the deforestation of entire watersheds, which has occurred in many Amazonian regions, may be a central factor for the functional homogenization of fish fauna.

scholarly journals Environmental constraints structuring fish assemblages in riffles: evidences from a tropical stream

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Fabrício Barreto Teresa ◽  
Luzia Shirlei de Souza ◽  
Dianne Michelle Alves da Silva ◽  
Hugo de Oliveira Barbosa ◽  
Jane Dilvana Lima ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Fish Assemblages ◽  
Environmental Control ◽  
Species Abundance ◽  
Dispersal Limitation ◽  
Ecological Processes ◽  
Structure Variation ◽  
Central Brazil ◽  
Environmental Variations ◽  
Trophic Traits

ABSTRACT Riffles are unique habitats regarding to assemblage structure. However, understanding how these assemblages respond to environmental variations in small spatial extents, as within a stream, is a challenge. We assess whether the quantitative structure and the trophic composition of fish assemblages vary predictably among stream riffles. We predict that the variation of environmental conditions will explain species abundance and trophic composition, with the latter presenting higher predictive power, since species would be filtered according to their traits (e.g. diet). Moreover, we expect that the low among-riffle dispersal limitation within a stream and the strong habitat filtering would result in lower importance of spatial variables in the structure of riffle fish assemblages. We tested these predictions by studying 18 riffles of a stream in the Central Brazil. Environmental variables, but not spatial ones, were the most important in explaining the variation in assemblages structure. Environmental variables explained a greater portion of the trophic structure variation (R2=0.62) than of abundance (R2=0.37), indicating that the variation on the trophic traits at community level are more predictable. These results also indicate that these assemblages are subject to environmental control, highlighting the importance of riffle characteristics in driving ecological processes within streams.

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