scholarly journals Metrics derived from fish assemblages as indicators of environmental degradation in Cerrado streams

2018 ◽  
Vol 35 ◽  
pp. 1-8
Author(s):  
Milton P. Ávila ◽  
Rafaela Neves Carvalho ◽  
Lilian Casatti ◽  
Juliana Simião-Ferreira ◽  
Lorrane Faria de Morais ◽  
...  
Keyword(s):  
Environmental Degradation ◽  
Fish Assemblages ◽  
Habitat Degradation ◽  
Conservation Status ◽  
Stream Fish ◽  
Physical Habitat ◽  
Dominance Index ◽  
Environmental Characteristics ◽  
Monitoring Tools ◽  
Stream Fish Assemblages

The development of effective monitoring tools depends on finding sensitive metrics that are capable of detecting the most important environmental impacts at a given region. We assessed if metrics derived from stream fish assemblages reflect physical habitat degradation and changes in land cover. We sampled the ichthyofauna and environmental characteristics of 16 stream sites of first and second order in the Upper Tocantins River basin. The streams were classified according to their environmental characteristics into reference (n = 5), intermediate (n = 4), and impacted (n = 7). A total of 4,079 individuals in five orders, 12 families, and 30 species were collected. Of the 20 metrics tested, eight were non-collinear and were tested for their performance in discriminating among groups of streams. Three metrics were sensitive to the gradient of degradation: Berger-Parker dominance index, percentage of characiform fish, and percentage of rheophilic individuals. Some commonly used metrics did not reflect the disturbances and many others were redundant with those that did. These results indicate that the metrics derived from fish assemblages may be informative for identifying the conservation status of streams, with the potential to be used in biomonitoring.

Community Ecology of Stream Fishes: Concepts, Approaches, and Techniques

2010 ◽  
Keyword(s):  
Indirect Effects ◽  
Fish Assemblages ◽  
Stream Fish ◽  
Physical Habitat ◽  
Stream Fishes ◽  
Land Uses ◽  
Study Region ◽  
Landscape Features ◽  
Temperature Regimes ◽  
Stream Fish Assemblages

<em>Abstract</em>.—Stream fish assemblages are influenced indirectly by natural and anthropogenic landscape features acting through intermediate factors like flow and temperature regimes, water quality, and physical habitat. These relationships affect distributions and abundances of individual species and also frame potential interactions among different types of fishes. This hierarchical influence of environmental factors, also known as the landscape perspective, is a widely accepted view of fluvial systems. However, few studies have attempted to quantify the complex mechanistic relationships among landscape variables, intermediate factors, and fish, a gap due partially to limitations of traditional analytical techniques for devolving such relationships. Using covariance structure analysis (CSA), we attempt to quantify the influence of natural and anthropogenic land uses on stream fish assemblages through indirect effects on fluvial physical habitat, including descriptors of habitat complexity, flow stability, and channel size, for 46 streams of southeastern Michigan. CSA was selected for this investigation because of its ability to quantify indirect effects of variables through intermediate factors and to account for intercorrelations among related measures. For analysis, fish assemblages were summarized by their richness and diversity and also according to functional groups that included trophic guilds and preferences for stream size, substrate, and geomorphological units, such as riffles and pools. Our analysis showed that, when acting through habitat factors, assemblages were more strongly influenced by natural landscape features, including catchment area and geology, than by anthropogenic land uses of our study region. Further, the analyses revealed that different aspects of fish assemblages varied with different habitat variables. While diversity and richness increased with habitat complexity and channel size, numbers of carnivores decreased with flow stability, possibly due to the link between flow and stream temperature regimes of our study region. Diversity and richness, however, were not affected by human land uses. Numbers of invertivores, fish preferring fine substrate, and fish preferring pool/ run habitat all increased with agriculture while numbers of detritivores increased with both agriculture and urban land use. These results emphasize complex effects of landscape features on stream fishes through intermediate factors and underscore the importance of understanding the varied response of different aspects of fish assemblages to environmental influences for improved conservation and restoration opportunities.

scholarly journals Land cover, riparian zones and instream habitat influence stream fish assemblages in the eastern Amazon

2018 ◽  
Vol 28 (2) ◽  
pp. 317-329 ◽  
Author(s):  
Luciano F. A. Montag ◽  
Kirk O. Winemiller ◽  
Friedrich W. Keppeler ◽  
Híngara Leão ◽  
Naraiana L. Benone ◽  
...  
Keyword(s):  
Land Cover ◽  
Fish Assemblages ◽  
Riparian Zones ◽  
Stream Fish ◽  
Stream Fish Assemblages

Fluctuation and variation in stream-fish assemblages after a catastrophic flood in the Miyagawa River, Japan

2011 ◽  
Vol 92 (4) ◽  
pp. 447-460 ◽  
Author(s):  
Yuichi Kano ◽  
Kaori Ohnishi ◽  
Yasuo Tomida ◽  
Naoyo Ikeda ◽  
Naomi Iwawaki ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Stream Fish ◽  
Catastrophic Flood ◽  
Stream Fish Assemblages

Diversity and stability in Mississippi stream fish assemblages

2012 ◽  
Vol 31 (3) ◽  
pp. 882-894 ◽  
Author(s):  
Jacob F. Schaefer ◽  
Scott R. Clark ◽  
Melvin L. Warren
Keyword(s):  
Fish Assemblages ◽  
Stream Fish ◽  
Stream Fish Assemblages

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

2019 ◽  
Keyword(s):  
Land Use ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Urban Land ◽  
Urban Land Use ◽  
Stream Fish ◽  
Landscape Variables ◽  
Stream Fish Assemblages ◽  
Anthropogenic Land Use ◽  
Assemblage Metrics

<i>Abstract.</i>—Anthropogenic activities including urbanization, agriculture, and dams degrade stream habitats and are a dominant reason for global biodiversity declines in fluvial fish assemblages. Declining diversity trends have been well documented in many regions of the world; however, fishes vary regionally in response to anthropogenic land use, resulting from complex relationships between landscape variables and mechanisms controlling stream fish assemblages. To test for differences in regional fish response to anthropogenic land use, we conducted our study across five freshwater ecoregions in the temperate mesic portion of the United States and evaluated data characterizing stream fish assemblages from 10,522 locations across all study freshwater ecoregions. Fishes were summarized by metrics describing assemblage structure, trophic groupings of species, levels of tolerance to anthropogenic stressors, and life history characteristics, with seven metrics used for analyses. Natural and anthropogenic landscape variables were assessed across freshwater ecoregions, and we tested for regionally specific influences of percent catchment urbanization, percent catchment agriculture, and catchment densities of dams and stream-road crossings on stream fishes. We used cascade multivariate regression trees to quantify variance explained in fish metrics by these landscape variables after controlling for influences of natural landscape variables, including catchment area, catchment lithology, and elevation of study sites. Results indicated differences in dominant influences by freshwater ecoregion, as well as differences in the levels of anthropogenic land use influencing fishes within and across freshwater ecoregions. For example, urban land use was the most influential anthropogenic land use in both Appalachian Piedmont and Chesapeake Bay freshwater ecoregions, with fish assemblage metrics showing responses at 10% and 1% catchment urban land use, respectively. In contrast, dam density in the network catchment was the most influential anthropogenic variable on fish assemblage metrics in both the Laurentian Great Lakes and Middle Missouri freshwater ecoregions. Also, large amounts of agriculture in the catchment was the most influential anthropogenic land use on fish assemblage metrics in the Upper Mississippi freshwater ecoregion. Knowledge of regional differences in the top contributing anthropogenic landscape variables and the levels at which fish assemblages respond to these variables lends insight into mechanisms controlling stream fish assemblages by freshwater ecoregions and can aid in development of region-specific conservation strategies to prevent biodiversity loss from current and future anthropogenic land use.

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