Environmental predictors of macroinvertebrate communities in coastal wetlands of southern Brazil

2008 ◽  
Vol 59 (6) ◽  
pp. 540 ◽  
Author(s):  
Cristina Stenert ◽  
Roberta C. Bacca ◽  
Carolina C. Mostardeiro ◽  
Leonardo Maltchik
Keyword(s):  
Environmental Factors ◽  
Water Depth ◽  
Habitat Diversity ◽  
Sediment Chemistry ◽  
Macroinvertebrate Communities ◽  
Southern Brazil ◽  
Ecological Data ◽  
Wetland Area ◽  
Aquatic Macroinvertebrate ◽  
Negatively Associated

The rapid degradation of wetlands worldwide accentuates the urgent need for ecological data to help manage and protect the threatened biodiversity in the remaining often-fragmented wetlands. In the Neotropics where fragmentation is common, environmental factors structuring aquatic macroinvertebrate communities are poorly known. We tested the hypothesis that physical features, such as wetland area, habitat diversity, water depth and temperature, and water and sediment chemistry are important correlates with richness, density and composition of wetland macroinvertebrate assemblages in Brazil. If so, do these correlations differ between summer and winter? A total of 16 895 individuals across 61 families were collected. Richness was positively associated with habitat diversity and water depth and negatively associated with water temperature. Macroinvertebrate density was negatively associated with water depth, and positively correlated with habitat diversity, percentage of sediment organic matter and water conductivity. Macroinvertebrate composition was associated mainly with wetland area and habitat diversity in the wetlands studied; these relationships persisted in both seasons. Our data illustrate environmental factors that potentially structure and maintain aquatic macroinvertebrate biodiversity in southern Brazil wetlands, and should be managed because 90% of these ecosystems have already been lost as a result of human activities.

Reduced riparian zone width compromises aquatic macroinvertebrate communities in streams of southern Brazil

2014 ◽  
Vol 186 (11) ◽  
pp. 7063-7074 ◽  
Author(s):  
Aline Bianca Moraes ◽  
Andréia Emília Wilhelm ◽  
Thaíse Boelter ◽  
Cristina Stenert ◽  
Uwe H. Schulz ◽  
...  
Keyword(s):  
Riparian Zone ◽  
Macroinvertebrate Communities ◽  
Southern Brazil ◽  
Aquatic Macroinvertebrate ◽  
Zone Width ◽  
Aquatic Macroinvertebrate Communities

Influence of area, altitude and hydroperiod on macroinvertebrate communities in southern Brazil wetlands

2007 ◽  
Vol 58 (11) ◽  
pp. 993 ◽  
Author(s):  
Cristina Stenert ◽  
Leonardo Maltchik
Keyword(s):  
Biological Diversity ◽  
Neotropical Region ◽  
Conservation Strategies ◽  
Macroinvertebrate Communities ◽  
Southern Brazil ◽  
Wetland Area ◽  
High Productivity ◽  
Intermittent Wetlands ◽  
Natural Wetlands ◽  
Richness Patterns

Wetlands are important ecosystems in southern Brazil because they show high productivity and biological diversity. However, conservative data indicate that ~90% of the wetlands have disappeared as a result of agricultural expansion. In this sense, the understanding of species composition and richness patterns in fragmented and natural wetlands is a priority for biodiversity conservation strategies. The main goal of the present study was to determine how much variation in macroinvertebrate richness and composition is explained by wetland area, hydroperiod and altitude. This survey was carried out in an extensive area of the Neotropical region (~280000 km2 – southern Brazil) with a large number of wetland systems (72) and covering a wide gradient of altitude and wetland surface area. The macroinvertebrate richness was higher in permanent wetlands than intermittent ones, and intermittent wetlands supported a macroinvertebrate composition that clearly differed from those of permanent wetlands. Macroinvertebrate richness was positively affected by wetland area; however, this relationship was significant only in permanent wetlands. There is a need to promote conservation of all wetland systems in southern Brazil, regardless of their hydroperiod and area. These arguments are essential to develop conservation and management programs of wetlands in this region.

The role of environmental factors in the composition of anuran species in several ponds under the influence of coal mining in southern Brazil

2017 ◽  
Vol 26 (3) ◽  
pp. 285-297 ◽  
Author(s):  
Guilherme S. De Lucca ◽  
Felipe A. P. Barros ◽  
J. Vladimir Oliveira ◽  
Jacir Dal Magro ◽  
Elaine M. Lucas
Keyword(s):  
Environmental Factors ◽  
Coal Mining ◽  
Southern Brazil ◽  
Anuran Species

Broadscale evaluation of the sedimentary Hg proxy for volcanism – insights from data compilation

2021 ◽  
Author(s):  
Joost Frieling ◽  
Isabel Fendley ◽  
Tamsin Mather
Keyword(s):  
Environmental Factors ◽  
Volcanic Activity ◽  
Sediment Chemistry ◽  
High Temporal Resolution ◽  
Gaseous Emissions ◽  
Mass Extinctions ◽  
Volcanic Emissions ◽  
Deep Time ◽  
The Past ◽  
Data Compilation

<p>Over the past few years, mercury (Hg) concentrations in (predominantly) marine sediments have gained widespread attention as a far-field, high-temporal resolution proxy for deep-time enhanced volcanic activity. The primary focus of these Hg studies has been a range of events in the past 500 million years; mostly larger and smaller mass extinctions and periods of high-amplitude climate change. As a result, sedimentary Hg data reinforced the notion many of these events are indeed coeval with and hypothesized causally connected to large igneous provinces (LIPs). </p><p>However, relatively poor constraints on long-term dispersal of emissions through the marine and terrestrial biosphere, accumulation and preservation mechanisms of Hg pose difficulties for its use as a qualitative proxy for enhanced volcanic emissions. As a result, using sedimentary Hg for detailed modeling of Hg cycling or past gaseous emissions of magmatic volatiles, e.g. carbon and sulfur, and by extension environmental impact, remains speculative.</p><p>The use of Hg normalization to common Hg-binding sedimentary components such as organic carbon (TOC), Fe or Al provides a basic means of comparing relative Hg loading within a sedimentary sequence. Yet, normalizing Hg to these major sedimentary components relies on simple linear relations and this approach often leaves substantial variance. While the high Hg concentrations have usually been ascribed to variability in volcanic activity, there are likely other factors that may invoke changes in the Hg concentrations in sediments, or mask Hg emitted by volcanism such as amount or type and flux of organic matter being deposited in basins and oxygenation of water and local sediments.</p><p>To evaluate potential confounding factors, we compiled published Hg, TOC and bulk and trace element data, modern and deep-time events, periods with and without known anomalous volcanic activity and cover a range of depositional settings. We find that the depositional setting, as inferred from lithology and bulk sediment chemistry exerts a major control on the overall concentrations of Hg. Differences in Hg loading between time-correlative deposits persist after normalization to major sedimentary components, likely as a result of a complex interplay between various spatial and environmental factors. Our data compilation further allows us to explore the potential of establishing a range for background Hg values and variability through different periods of geological deep-time. Collectively, such constraints can aid the understanding of changes induced by environmental factors or volcanic emissions and inform Hg-cycling models.</p>

E-Business Assimilation in China’s International Trade Firms

2011 ◽  
pp. 150-176
Author(s):  
Dahui Li ◽  
Fujun Lai ◽  
Jian Wang
Keyword(s):  
Economic Development ◽  
International Trade ◽  
Supply Chain ◽  
Environmental Factors ◽  
Environmental Uncertainty ◽  
Relative Advantage ◽  
Ownership Type ◽  
Beijing Area ◽  
Negatively Associated ◽  
It Capability

Despite the importance of international trade firms in China’s economic development, there is only limited empirical evidence about how these firms assimilate Internet-based e-business in global supply chain operations. Using the Technology-Organization-Environment framework, this study investigates technological, organizational, and environmental factors which determine e-business assimilation in these firms. Based on survey data collected from 307 international trade firms in the Beijing area, we found that environmental uncertainty was negatively associated with e-business assimilation, while a firm’s internal IT capability, relative advantage of e-business, learning orientation, and inter-organizational dependence were positive determinants of e-business assimilation. The effect of a firm’s ownership type was also significant. Environmental uncertainty was the most important inhibitor, and IT capability and inter-organizational dependence were the most salient enablers of e-business assimilation.

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