scholarly journals Mild impacts do not subsidize aquatic insect communities in an Atlantic Forest stream

2021 ◽  
Author(s):  
Celio Roberto Jonck ◽  
Luiza Hoehne Mattos de Oliveira ◽  
Rafael Jordão Pires Silva ◽  
Jorge Luiz Nessimian
Keyword(s):  
Atlantic Forest ◽  
Environmental Quality ◽  
Stress Gradient ◽  
Urban Stream ◽  
Biotic Index ◽  
Urban Settlement ◽  
Low Intensity ◽  
Agricultural Stream ◽  
Reference Stream ◽  
Diversity Metrics

AbstractOdum’s perturbation theory hypothesizes that toxic pollutants cause damage to ecosystems early in the course of contamination. In contrast, organic pollutants enrich the ecosystem until it exceeds their carrying capacity, an effect known as the subsidy-stress gradient. Understanding this dynamic can improve the efficiency of river restoration programs and bring significant benefits to society by providing ecosystem services that were lost. However, the initial effects of the most common human-induced disturbances in Atlantic Forest streams are not well known, indicating the necessity to evaluate the subsidy-stress gradient in these vulnerable and diverse ecosystems.AimWe evaluated the composition and abundance of the community of aquatic insects from leaf litter of headwater streams in three conditions: a fully forested area (reference stream), a low-intensity urban settlement (urban stream), and a region with small farms dedicated to the cultivation of fruits and vegetables (agricultural stream).MethodsWe used alpha and beta diversity metrics and a specific biotic index to test the subsidy-stress gradient prediction.ResultsThe agricultural stream showed the most degraded ecological condition. The urban stream and the reference stream showed similarity in alpha diversity metrics. According to the biotic index, the streams showed a gradient of environmental quality, with the reference stream showing the best quality and the agricultural stream the worst quality.ConclusionsThe agricultural stream showed a decrease in the environmental quality consistent with the effect predicted by the subsidy-stress gradient due to toxic pollutants’ contribution. However, the low-intensity enrichment of organic matter from the urban settlement causes a disorder in the ecosystem that reduces its environmental quality, contrary to the predicted by the subsidy-stress gradient.

scholarly journals Nitrate retention and removal in Mediterranean streams bordered by contrasting land uses: a <sup>15</sup>N tracer study

2009 ◽  
Vol 6 (2) ◽  
pp. 181-196 ◽  
Author(s):  
D. von Schiller ◽  
E. Martí ◽  
J. L. Riera
Keyword(s):  
Agricultural Land ◽  
N Cycling ◽  
Urban Stream ◽  
Relative Importance ◽  
Transfer Velocity ◽  
Nitrate Retention ◽  
Relative Contribution ◽  
Uptake Length ◽  
Agricultural Stream ◽  
Forested Stream

Abstract. We used 15N-labelled nitrate (NO3−) additions to investigate pathways of nitrogen (N) cycling at the whole-reach scale in three stream reaches with adjacent forested, urban and agricultural land areas. Our aim was to explore among-stream differences in: (i) the magnitude and relative importance of NO3− retention (i.e. assimilatory uptake) and removal (i.e. denitrification), (ii) the relative contribution of the different primary uptake compartments to NO3− retention, and (iii) the regeneration, transformation and export pathways of the retained N. Streams varied strongly in NO3− concentration, which was highest in the agricultural stream and lowest in the forested stream. The agricultural stream also showed the lowest dissolved oxygen (DO) concentration and discharge. Standing stocks of primary uptake compartments were similar among streams and dominated by detritus compartments (i.e. fine and coarse benthic organic matter). Metabolism was net heterotrophic in all streams, although the degree of heterotrophy was highest in the agricultural stream. The NO3− uptake length was shortest in the agricultural stream, intermediate in the urban stream, and longest in the forested stream. Conversely, the NO3− mass-transfer velocity and the areal NO3− uptake rate were highest in the urban stream. Denitrification was not detectable in the forested stream, but accounted for 9% and 68% of total NO3− uptake in the urban and the agricultural stream, respectively. The relative contribution of detritus compartments to NO3− assimilatory uptake was greatest in the forested and lowest in the agricultural stream. In all streams, the retained N was rapidly regenerated back to the water column. Due to a strong coupling between regeneration and nitrification, most retained N was exported from the experimental reaches in the form of NO3−. This study provides evidence of fast in-stream N cycling, although the relative importance of N retention and removal varied considerably among streams. Results suggest that permanent NO3− removal via denitrification may be enhanced over temporary NO3− retention via assimilatory uptake in heterotrophic human-altered streams characterized by high NO3− and low DO concentrations.

scholarly journals BIOCAPACITY OF BRAZILIAN BIOMES USING EMERGY ECOLOGICAL FOOTPRINT CONCEPTS

2021 ◽  
Vol 24 ◽  
Author(s):  
Wallan Azevedo dos Santos ◽  
Milton Erthal Junior ◽  
Renato Gomes Sobral Barcellos
Keyword(s):  
Sustainable Development ◽  
Atlantic Forest ◽  
Environmental Quality ◽  
Quality Indicator ◽  
Ecological Footprint ◽  
Forest Cover ◽  
Kriging Method ◽  
The World ◽  
Pessimistic Scenario ◽  
Forest Coverage

Abstract This work aimed to assess Brazilian biomes’ biocapacity (BC) using concepts of the Emergy Ecological Footprint method. Climate and forest cover data were interpolated using the Kriging method. In 2016, the Brazilian BC was among the largest in the world, 42.11 gha / cap. The biomes’ forest coverage areas were investigated and simulated in two scenarios: optimistic (with 100% forest coverage) and pessimistic (only 10%). The Amazon’s contribution of half the Brazilian BC would reduce by 88% in a pessimistic scenario. The Atlantic Forest contribution was only 1.9% of the national BC, however, in an optimistic scenario, it would increase by 690%. The reduction of deforestation, fires and expansion of areas protected by law are measures that positively impact the BC of the studied biomes. This methodology can be used as an environmental quality indicator as it adheres to the principles of Sustainable Development.

scholarly journals Live benthic foraminiferal faunas from the French Mediterranean Coast: Towards a new biotic index of environmental quality

2014 ◽  
Vol 36 ◽  
pp. 719-743 ◽  
Author(s):  
Christine Barras ◽  
Frans J. Jorissen ◽  
Céline Labrune ◽  
Bruno Andral ◽  
Pierre Boissery
Keyword(s):  
Environmental Quality ◽  
Mediterranean Coast ◽  
Biotic Index

Are biochemical composition parameters of sediment good tools for assessing the environmental quality of estuarine areas in tropical systems?

2017 ◽  
Vol 99 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Fred B. Silva ◽  
Janilson F. Silva ◽  
Ranilson S. Bezerra ◽  
Paulo J. P. Santos
Keyword(s):  
Organic Matter ◽  
Environmental Quality ◽  
Biochemical Composition ◽  
Trophic State ◽  
Biotic Index ◽  
Anthropogenic Pressure ◽  
Eastern Brazil ◽  
Initial Stage ◽  
Natural Productivity

The present study aims to assess the environmental quality of six estuaries in north-eastern Brazil, using biochemical composition and quantity of organic matter in tropical sediments. Samples were collected monthly during spring low tide from August 2011 to July 2012, in the mid-littoral. Concentrations of organic matter and its biochemical composition reflected the degree of anthropogenic pressure. Although total concentrations of proteins and carbohydrates were similar among estuaries with contrasting levels of anthropogenic pressure, the protein to carbohydrates (PRT : CHO) ratio effectively reflected the trophic state of these areas. PRT : CHO ratios >1 were observed in all studied areas suggesting eutrophic conditions or an initial stage of eutrophication in all of them. Low Chl-a/Phaeo ratios may be associated with the level of eutrophication of each area, however it may also reflect the natural productivity or the presence of mangrove debris. These results were compared with those obtained in previous environmental assessments of the same estuarine areas using the AZTI Marine Biotic Index and monitoring reports showing good agreement. The present study confirmed for the first time in tropical estuarine areas that the biochemical approach can be successfully used to assess the trophic state of the benthic compartment.

Fragment configuration or environmental quality? Understanding what really matters for the conservation of native mammals in the Atlantic Forest of Argentina

2019 ◽  
Vol 52 ◽  
pp. 125751
Author(s):  
María Eugenia Iezzi ◽  
Paula Cruz ◽  
Diego Varela ◽  
Mario S. Di Bitetti ◽  
Carlos De Angelo
Keyword(s):  
Atlantic Forest ◽  
Environmental Quality

scholarly journals Nitrate retention and removal in Mediterranean streams with contrasting land uses: a <sup>15</sup>N tracer study

2008 ◽  
Vol 5 (4) ◽  
pp. 3307-3346 ◽  
Author(s):  
D. von Schiller ◽  
E. Martí ◽  
J. L. Riera
Keyword(s):  
N Cycling ◽  
Trophic Levels ◽  
Urban Stream ◽  
Land Uses ◽  
Mediterranean Streams ◽  
Transfer Velocity ◽  
Nitrate Retention ◽  
Relative Contribution ◽  
Uptake Length ◽  
Agricultural Stream

Abstract. We used 15N-labelled nitrate (NO−3) additions to investigate nitrogen (N) cycling at the whole-reach scale in three Mediterranean streams subjected to contrasting land uses (i.e. forested, urban and agricultural). Our aim was to examine: i) the magnitude and relative importance of NO−3 retention (i.e. assimilatory uptake), and removal, (i.e. denitrification), ii) the relative contribution of the different primary uptake compartments to NO−3 retention, and iii) the regeneration, transformation and export pathways of the retained N. The concentration of NO−3 increased and that of dissolved oxygen (DO) decreased from the forested to the agricultural stream, with intermediate values in the urban stream. Standing stocks of primary uptake compartments were similar among streams and dominated by detritus compartments (i.e. fine and coarse benthic organic matter). In agreement, metabolism was net heterotrophic in all streams, although the degree of heterotrophy increased from the forested to the agricultural stream. The NO−3 uptake length decreased along this gradient, whereas the NO−3 mass-transfer velocity and the areal NO−3 uptake rate were highest in the urban stream. Denitrification was not detectable in the forested stream, but accounted for 9% and 68% of total NO−3 uptake in the urban and the agricultural stream, respectively. The relative contribution of detritus compartments to NO−3 assimilatory uptake was highest in the forested and lowest in the agricultural stream. In all streams, the retained N was rapidly transferred to higher trophic levels and regenerated back to the water column. Due to a strong coupling between regeneration and nitrification, most retained N was exported from the experimental reaches in the form of NO−3. This study evidences fast N cycling in Mediterranean streams. Moreover, results indicate that permanent NO−3 removal via denitrification may be enhanced over temporary NO−3 retention via assimilatory uptake in heterotrophic human-altered streams characterized by high NO−3 and low DO concentrations.

Native trees for environmental quality assessment in an ecological corridor of Atlantic Forest

2011 ◽  
Vol 5 (1/2) ◽  
pp. 4 ◽  
Author(s):  
Andre L.L. De Araujo ◽  
Elisabete A. De Nadai Fernandes ◽  
Marcio A. Bacchi ◽  
Elvis J. Franca
Keyword(s):  
Quality Assessment ◽  
Atlantic Forest ◽  
Environmental Quality ◽  
Environmental Quality Assessment ◽  
Native Trees ◽  
Ecological Corridor

Objective derivation of macro invertebrate family sensitivity grade numbers for the SIGNAL biotic index: application to the Hunter River system, New South Wales

1997 ◽  
Vol 48 (2) ◽  
pp. 159 ◽  
Author(s):  
Bruce C. Chessman ◽  
Jane E. Growns ◽  
Amanda R. Kotlash
Keyword(s):  
Iterative Algorithm ◽  
Environmental Quality ◽  
Environmental Variables ◽  
New South ◽  
New South Wales ◽  
River System ◽  
Biotic Index ◽  
Mean Values ◽  
South Wales ◽  
Highly Correlated

Chessman's SIGNAL-95 biotic index was modified on the basis of data from spring and autumn surveys of macroinvertebrates at 42 sites in the Hunter River and tributaries. An iterative algorithm was used to derive improved grade numbers reflecting the pollution sensitivities of individual families of river macroinvertebrates. The new grades were used to calculate values of the modified index (SIGNAL-HU97). These values were highly correlated with SIGNAL-95 values but were more widely spread, giving better discrimination between the sites of higher environmental quality and the more degraded sites. SIGNAL-HU97 values were also more highly correlated than were SIGNAL-95 values with environmental variables such as the conductivity of the water and a riparian, channel and environmental inventory. There was little difference in values between spring and autumn, but riffles consistently had higher mean values than other habitats.

A framework to evaluate the environmental quality and simulate future scenarios of urban forests: atlantic forest case study

2020 ◽  
Author(s):  
Felipe Hashimoto Fengler ◽  
Jener Fernando Leite de Moraes ◽  
Admilson Irio Ribeiro ◽  
Marcela Merides Carvalho ◽  
Afonso Peche Filho ◽  
...  
Keyword(s):  
Atlantic Forest ◽  
Environmental Quality ◽  
Urban Forests ◽  
Future Scenarios
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