scholarly journals Composition and diversity of Ephemeroptera (Insecta) nymph communities in the middle section of the Jacuí River and some tributaries, southern Brazil

2008 ◽  
Vol 98 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Ana Emilia Siegloch ◽  
Claudio Gilberto Froehlich ◽  
Carla B. Kotzian
Keyword(s):  
Riparian Vegetation ◽  
Habitat Complexity ◽  
New Records ◽  
Taxonomic Composition ◽  
Environmental Stability ◽  
Southern Brazil ◽  
Lotic Environments ◽  
Anthropic Influence ◽  
Surber Sampler

The taxonomic composition and diversity of assemblages of Ephemeroptera nymphs of four lotic environments in the central region of State of Rio Grande do Sul, a subtropical area in southern Brazil, were evaluated. Samplings were done monthly, with a Surber sampler, from June 2001 to May 2002, in the Jacuí River and three of its tributaries. The total number of nymphs collected in the four sampling sites was 11,007 in five families and 19 genera, of these, 11 are new records for the State. The highest diversity occurred in Point 4 (H'=2.41) and the lowest in Point 2 (H'=1.69). Point 4 had the highest environmental stability, conservation of the riparian vegetation and the lowest anthropic impact, while Point 2 presented a large environmental simplification due to a direct anthropic influence (e.g. domestic sewerage, trampling by cattle). The diversity of nymphs observed in the total area is high, compared to the estimated maximum theoretical diversity; a result of the high evenness and richness recorded. Rarefaction curves, calculated for a sample of 1,018 specimens, showed a similar expectation of richness for the four sampling sites. This result seems to be associated with the overall environmental homogeneity of the region caused by long-term alterations (land use and deforestation). In summary, higher diversity of Ephemeroptera nymph assemblages seems to be associated with habitat complexity, a good vegetation cover and a lower anthropic influence.

scholarly journals Composition and diversity of Trichoptera (Insecta) larvae communities in the middle section of the Jacuí river and some tributaries, State of Rio Grande do Sul, Brazil

2006 ◽  
Vol 96 (4) ◽  
pp. 389-398 ◽  
Author(s):  
Marcia R. Spies ◽  
Claudio G. Froehlich ◽  
Carla B. Kotzian
Keyword(s):  
Riparian Vegetation ◽  
Rio Grande ◽  
Taxonomic Composition ◽  
Rio Grande Do Sul ◽  
Middle Section ◽  
Low Diversity ◽  
Anthropic Influence ◽  
Study Sites ◽  
Physical Features ◽  
Surber Sampler

The taxonomic composition and diversity of Trichoptera larvae communities were studied in four lotic sites in central region of State of Rio Grande do Sul. Sampling was done monthly from June, 2001 to May, 2002 in four sites located at the middle section of Jacuí River (Point 4) and in three tributaries (Carijinho River - Point 1; Lajeado da Gringa - Point 2 and Lajeado do Gringo - Point 3), with a Surber sampler. The total number of larvae collected was 29,143, belonging to 25 genera distributed in nine families; twenty of these genera are new records for the State. The highest abundance was found at Point 2 (n = 12,547). The highest standardized richness, for a 1,177 specimens sample chosen by chance, was recorded at Point 1, followed by Point 4 (17.7 and 16 genera, respectively). The highest diversity was found at Point 1, and the lowest at Point 3 (H' = 1.31 and H' = 0.77, respectively). Point 1 had the lowest anthropic influence and the best preserved riparian vegetation, while Point 3 presented the highest anthropic impact, and a very reduced riparian vegetation. The diversity of Trichoptera observed in this study is low, compared to the estimated maximum theoretical diversity. Low diversity values are related to the low evenness, since the richness was relatively high. The Trichoptera larvae communities seem to be related to the food availability and physical features (riparian vegetation and anthropic influence) of the study sites.

scholarly journals Indoor radon concentration and a diffusion model in dwellings situated in a subalkaline granitoid area, Southern Brazil

2021 ◽  
Vol 80 (17) ◽  
Author(s):  
G. Romero-Mujalli ◽  
A. Roisenberg ◽  
A. Cordova-Gonzalez ◽  
P. H. P. Stefano
Keyword(s):  
Diffusion Model ◽  
Indoor Radon ◽  
Southern Brazil ◽  
High Concentration ◽  
Indoor Radon Concentration ◽  
One Dimensional ◽  
Environmental Limits ◽  
Radon Measurements ◽  
Cr 39 Detectors

AbstractRadon (Rn), a radioactive element, has especial interest in medical geology because long-term exposure to high concentration is related to lung cancer. In this study, outdoor and indoor radon measurements were conducted in dwellings of the Piquiri Syenite Massif, located in southern Brazil, given the relative high Rn content in soils of this region. Measurements were done using CR-39 detectors and placing them inside and outside dwellings. Moreover, a one-dimensional diffusion model was performed in order to quantify the natural transport of Rn to the air in confined and aerated environments. Results indicate that the region presents relatively low air Rn concentrations, within the environmental limits; however, the health risk might increase in confined and ill-ventilated environments because of transfer from soil and exhalation from ornamental rock-material often found inside dwellings. The main north facies of the syenite, where most of the rock extractions are located, was found to have the highest air Rn concentration because of the higher soil Rn concentration, compared to other facies of the syenite.

scholarly journals Stability of graphene-based heterojunction solar cells

RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 73575-73600 ◽  
Author(s):  
Eric Singh ◽  
Hari Singh Nalwa
Keyword(s):  
Solar Cells ◽  
Environmental Stability ◽  
Light Illumination ◽  
Atmospheric Conditions ◽  
Air Humidity ◽  
Heterojunction Solar Cells ◽  
Commercial Applications

The long-term environmental stability and degradation of graphene-based heterojunction solar cells under different atmospheric conditions such as air, humidity, temperature, and light illumination for commercial applications are discussed.

scholarly journals Trends in the Frequency of Intense Precipitation Events in Southern and Southeastern Brazil during 1960–2004

2011 ◽  
Vol 24 (7) ◽  
pp. 1913-1921 ◽  
Author(s):  
Mateus da Silva Teixeira ◽  
Prakki Satyamurty
Keyword(s):  
Extreme Rainfall ◽  
Southeastern Brazil ◽  
Extreme Rainfall Event ◽  
Southern Brazil ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Annual Frequency ◽  
Long Term Trends ◽  
Increasing Trends

Abstract A new approach to define heavy and extreme rainfall events based on cluster analysis and area-average rainfall series is presented. The annual frequency of the heavy and extreme rainfall events is obtained for the southeastern and southern Brazil regions. In the 1960–2004 period, 510 (98) and 466 (77) heavy (extreme) rainfall events are identified in the two regions. Monthly distributions of the events closely follow the monthly climatological rainfall in the two regions. In both regions, annual heavy and extreme rainfall event frequencies present increasing trends in the 45-yr period. However, only in southern Brazil is the trend statistically significant. Although longer time series are necessary to ensure the existence of long-term trends, the positive trends are somewhat alarming since they indicate that climate changes, in terms of rainfall regimes, are possibly under way in Brazil.

scholarly journals Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities

2014 ◽  
Vol 281 (1775) ◽  
pp. 20132479 ◽  
Author(s):  
K. E. Fabricius ◽  
G. De'ath ◽  
S. Noonan ◽  
S. Uthicke
Keyword(s):  
Ocean Acidification ◽  
Habitat Complexity ◽  
Atmospheric Carbon Dioxide ◽  
Coral Cover ◽  
Ecological Effects ◽  
Macroinvertebrate Communities ◽  
Dead Coral ◽  
Marine Communities

The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO 2 ) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO 2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO 2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO 2 (425–1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO 2 tolerances derived from laboratory experiments. High CO 2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs.

Flora of technologenic landscapes of the taiga zone of the European North-East (Komi Republic)

2021 ◽  
Author(s):  
V.A. Martynenko ◽  
◽  
B.I. Gruzdev
Keyword(s):  
Vascular Plants ◽  
Komi Republic ◽  
Taxonomic Composition ◽  
Taiga Zone ◽  
North East ◽  
Annotated List ◽  
European North ◽  
Disturbed Areas ◽  
Synanthropic Flora

The results of a long-term studu of the flora of technologenichabitats of the taiga zone of the Komi Republic are summarized. An annotated list of vascular plants is presented, including 406 species from 222 genera and 52 families. For each of them, it is indicated that they belong to a life from, an element of the flora and type of area, an ecologicsl group, zonal and ecotopic affinity. Data on the taxonomic composition of vascular plants, the biomorphrological, geographical, and ecological structures of synanthropic flora, the diversity of synanthropic plant communities, and the stages of vegetation restoration in disturbed areas are presented.

New records of Trachelomonas Ehrenberg (Euglenophyceae) in lotic environments of the buffer zone of Iguaçu National Park, Paraná, Brazil

2015 ◽  
Vol 38 (2) ◽  
pp. 343-356
Author(s):  
Liliane Caroline Servat ◽  
Norma Catarina Bueno ◽  
Sandra Maria Alves-da-Silva
Keyword(s):  
National Park ◽  
New Records ◽  
Buffer Zone ◽  
Lotic Environments

Soil nitrous oxide emissions as affected by long-term tillage, cropping systems and nitrogen fertilization in Southern Brazil

2015 ◽  
Vol 146 ◽  
pp. 213-222 ◽  
Author(s):  
Cimélio Bayer ◽  
Juliana Gomes ◽  
Josiléia Accordi Zanatta ◽  
Frederico Costa Beber Vieira ◽  
Marisa de Cássia Piccolo ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Fertilization ◽  
Cropping Systems ◽  
Nitrous Oxide Emissions ◽  
Southern Brazil

Late Quaternary vegetation dynamics in a biodiversity hotspot, the Uluguru Mountains of Tanzania

2009 ◽  
Vol 72 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Jemma Finch ◽  
Melanie J. Leng ◽  
Rob Marchant
Keyword(s):  
Environmental Changes ◽  
Vegetation History ◽  
Late Quaternary ◽  
Anthropogenic Activities ◽  
Significant Loss ◽  
Environmental Stability ◽  
Forest Composition ◽  
Eastern Arc ◽  
Uluguru Mountains

AbstractLate Quaternary vegetation history and environmental changes in a biodiverse tropical ecosystem are inferred from pollen, charcoal and carbon isotope evidence derived from a ∼ 48,000-yr sedimentary record from the Uluguru Mountains, a component of the Eastern Arc Mountains of Kenya and Tanzania. Results indicate that Eastern Arc forest composition has remained relatively stable during the past ∼ 48,000 yr. Long-term environmental stability of the Eastern Arc forests has been proposed as a mechanism for the accumulation and persistence of species during glacial periods, thus resulting in the diverse forests observed today. The pollen and isotope data presented here indicate some marked changes in abundance but no significant loss in moist forest taxa through the last glacial maximum, thereby providing support for the long-term environmental stability of the Eastern Arc. Anthropogenic activities, including burning and forest clearance, were found to play a moderate role in shaping the mosaic of forest patches and high-altitude grasslands that characterise the site today; however, this influence was tempered by the inaccessibility of the mountain.

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