Rosane Maria Lanzer

Mosses as indicators of atmospheric metal deposition in an industrial area of southern Brazil

Caxias do Sul hosts the second largest metal-mechanic pole in Brazil, which increases the risk of atmospheric contamination. With the aim of identifying species that might be useful as indicators of atmospheric deposition of metals, 15 species of mosses from an urban and a rural setting were analyzed and compared with specimens deposited at the Herbarium of the Universidade de Caxias do Sul. Metal concentrations (Zn, Ni, Cd, Cr, Cu and Pb) were determined using Atomic Absorption Spectrometry (AAS). The Mann-Whitney test indicated concentrations of Zn, Cu, Pb and Cr that were significantly different between the urban and rural areas. Additionally, Concentrations of Zn, Cd, Cu and Pb were significantly higher in recently collected samples. The species Thuidium tomentosum Besch., Sematophyllum subpinnatum (Brid.) E. Britton, Helicodontium capillare (Hedw.) A. Jaeger, Schlotheimia jamesonii (W.-Arnott) Brid. and Meteorium deppei (Hornsch. ex Mull. Hal.) Mitt. are potential biomonitors of atmospheric metal deposition.

Hydrological stress as a limiting factor of the invasion of Limnoperna fortunei (Dunker, 1857) in the Upper Paraná River (Brazil)

Limnoperna fortunei (Dunker, 1857), is an asiatic mussel that arrived in South America in 1991. Since 2004, we have noticed that the advance of this species in the lower Paranaiba River, a tributary of the Upper Parana River, is slow when compared to the average speed of 240 km/year in the Parana River (middle and lower course). AIM: The goal of this work is to understand what factors are limiting the spread of L. fortunei in this stretch of the Paranaiba River. METHODS: Its occurrence and dispersion were sampled twelve times between March 2006 and November 2007 in the Paranaiba River, including the Sao Simao hydroelectric reservoir. Physicochemical characteristics of the water were analysed, and a Stream Length-Gradient Index calculated for the study area. RESULTS: Adult mussels were easily found attached to the hulls of barges that travel on this stretch of the Parana-Tiete waterway and on vessels that were docked in the harbours of grain exporters located in Sao Simao (GO). However, no larvae or adults were found near the harbours or upstream from them at the Sao Simao hydroelectric reservoir. The pH and concentration of calcium and dissolved oxygen values among lotic habitats and the reservoir were similar: DO values were close to 7 mg.L-1, the average pH was near 7, average values of total Ca ranged between 4 and 6 mg.L-1 and the chlorophyll-a levels were not restrictive to the mussel. CONCLUSION: Physical and chemical water parameters show that habitats were suitable for establishment of the mussel. In addition to a low pressure of propagules, this paper proposes some hydrological variables, such as the energy of the fluvial stretches, expressed by the Stream Length-Gradient Index and changes in flow downstream of the dam as barriers to the establishment of the species, discouraging larval settlement, and decreasing survival and recruitment.

Tolerance of benthic macroinvertebrates to organic enrichment in highland streams of northeastern Rio Grande do Sul, Brazil

AIM: the aim of this study was to determine the ecological valence of benthic macroinvertebrates at different pollution levels in highland rivers and streams of Rio Grande do Sul; METHODS: the dataset proceeds from samplings performed between 2002-2011 in 35 lotic ecosystems. The Chemical Index was used to determine pollution levels. Indices of richness and Shannon diversity were applied to characterize the structure of benthic communities. The descriptors used to determine taxas ecological valence were selected according to Coefficient of Variation and regression analyses. Groups of tolerance were identified using Interquartile range and cluster analysis; RESULTS: Conductivity and Chemical Index were the descriptors best related with diversity of benthic macroinvertebrate community. These metrics were used to determine the tolerance range of 38 taxa. Interquartile range and cluster analysis revealed three groups of taxa, according to their occurrence in different levels of pollution: taxa with narrow amplitudes, present at sites with very low or very high load of organic enrichment; taxa with moderate amplitude, found until moderately polluted sites; and taxa with occurrence in widespread environmental conditions. The results, when compared to other studies in Brazil, showed differences in some taxas tolerance. This observation indicates the need to assess the bioindication potential of these taxa in genus and species level; CONCLUSION: the present study contributes to increase knowledge about the bioindicator potential of benthic macroinvertebrates. Therefore, the study supports an advanced biomonitoring of ecological quality in mountain streams of southern Brazil.

Diversity and spatial and temporal variation of benthic macroinvertebrates with respect to the trophic state of Lake Figueira in the South of Brazil

Benthic macroinvertebrates are widely used in evaluations of environmental impact and recommended in biomonitoring, but little used in Brazilian lentic environments. One of the main objectives has been to explain and predict the distribution of those species according to environmental characteristics. Thus, the study aims to characterize the predominant fauna of the Lake Figueira sediment and its relationship with organic matter and depth, analyzing seasonal variation in communities and aiming to select bioindicators of the trophic state. Sampling was carried out from January 2008 to January 2009, along the lagoon fetch, with an Ekmann-Birge dredge (area 225 cm2). Taxon richness was not significantly related with depth and organic matter content, but those variables were highly correlated (r = 0.962; r2 = 0.926 and p < 0.001). The constant oxygenation of the whole water column allows the occurrence of organisms, independent of depth and organic matter content. Chironomidae was the most abundant taxon and from the frequency of occurrence, abundance and clustering analysis it was possible to select Larsia sp. , Goeldichironomus maculatus, Xenochironomus sp. , Aedokritus sp. Cladopelma forcipis, Cryptochironomus brasiliensis, Nilothauma sp.1 and Caladomyia sp. C, Tanytarsus sp. , Tanytarsus rhabdomantis and Chironomus gr. salinarius as potential indicators related with the spatiotemporal faunal distribution of Lake Figueira.

Morphological characterization of eighteen lakes of the north and middle coast of Rio Grande do Sul, Brazil

AIMS: The present study aimed at a morphological characterization of 18 lakes of the municipalities of Cidreira, Balneario Pinhal and Palmares do Sul, situated in the northern and middle coastal plain of Rio Grande do Sul, Brazil. METHODS: The morphometric survey was conducted in the summer of 2011/2012, based on echo sounder coupled with GPS and the application of remote sensing and GIS procedures. The morphometric parameters used for the characterization were: surface area, perimeter, perimeter development, volume, relative fetch, maximum depth, average depth, relative depth, median depth of volume, length and width. The statistical interpretation included Test of Normality, Coefficient of Variation, Correlation and Regression Analysis, Cluster Analysis, Discriminant Analysis and Principal Component Analysis. RESULTS: Eighteen lakes were described and five of them are presented by aerial photo and bathymetric map. They represent the proposed morphological lake types. The calculation of the coefficient of variation revealed larger amplitudes of parameters related to lake size than to depth. The application and interpretation of cluster analysis, confirmed by discriminant analysis, distinguished those lakes in five morphological groups, which differ mainly by size and subsequently by depth. The Principal Component Analysis identified the first component with positively charged variables of size and negatively charged relative depth, and a second component with positive charge of maximum and average depths. CONCLUSIONS: The low relative depths and the exposure to constant northeastern winds reduce the transparency of the lakes. Consequently, they are light limited by suspension of inorganic and organic matter. A property that limits the application of trophic state indices. The high dynamic of the water bodies produces an oxygenated sediment surface that facilitates the settlement by aerobic organisms all over the bottom area. The shallowness and the low median depths of volume are limiting factors for sustainable water supply management. The morphological characteristics of the coastal lakes make very difficult an accurate ecological assessment based on usual trophic state criterions and a sustainable water resource management using general guidelines.

The Intersections Between Lacustrine Wildlife Tourism and Conservation: Scientific and Educational Opportunities in the Brazilian Southern Lakes

Taken as an activity on the rise in the contemporary world, tourism increasingly leans towards natural areas, especially coastal regions. Brazil stands out for its extensive coastline and attractions related to sun and beach. However, the interaction between tourism and these ecosystems is not much debated. In the state of Rio Grande do Sul, southern Brazil, a unique coastline can be found. This region has the most extensive coastal plain of Brazil, with 37,000 km2 and about 100 freshwater shallow lakes along its coastline. Geological processes, combined with a specific biological system, have conditioned a differentiated landscape in the region, composed of an ecosystem mosaic of sand dunes, restinga forest formations, wetlands and shallow lakes, which harbor their own biodiversity, including human beings that depend on these ecosystems for survival. Such resources are constantly under pressure of human activities, tourism among them, since touristic activities in these environments do not take into account their fragility. As a result, several fauna and flora species are damaged by the pursuit of human leisure, as well as by mismanagement of water resources. Thus, this study aims to discuss the relations between tourism and the freshwater environments, seeking to quantify the lack of knowledge about the species inhabiting these ecosystems, which affects sustainable practices planning. This study shows that, even in the presence of unique landscapes in scenarios of great beauty and frail ecosystems, the rich biodiversity is impacted by urbanization. Human activities affect the lakes environmental quality, harming biodiversity and tourism development in the region. Management models need to undergo changes, through the implementation of environmental education programs and promoting new forms of tourism, like scientific tourism, and wildlife conservation.