Brazilian Wetlands Research Articles

Isolation and characterization of polymorphic microsatellites in the threatened catfish Jaú, Zungaro jahu (Siluriformes, Pimelodidae)

This paper describes eight polymorphic microsatellite loci of the large migratory catfish Jau, Zungaro jahu, a threatened species in the Paraguay—Parana River Basin, which includes the Brazilian wetland Pantanal system. The number of detected alleles varied from 3 to 10, while observed and expected heterozygosity values ranged from 0.3182 to 0.8333 and 0.3298 to 0.8652, respectively. Cross-amplification on five related species was successfully evaluated. These isolated markers demonstrated to be very useful for population studies of this fish and related species, consisting in important tools for evaluations related to the management and conservation of the native populations.

Soil morphological control on saline and freshwater lake hydrogeochemistry in the Pantanal of Nhecolândia, Brazil

Joint pedological, geochemical, hydrological and geophysical investigations were performed to study the coexistence of saline and freshwater lakes in close proximity and similar climatic conditions in the Nhecolândia region, Pantanal wetlands in Brazil. The saline lakes are concentrically surrounded by green sandy loam horizons, which cause differential hydrological regimes. Mg-calcite, K-silicates, and amorphous silica precipitate in the soil cover, whereas Mg-silicates and more soluble Na-carbonates are concentrated in the topsoil along the shore of the saline lake. In saline solutions, some minor elements (As, Se) reach values above the water quality recommendations, whereas others are controlled and incorporated in solid phases (Ba, Sr). Locally, the destruction of the sandy loam horizons generates very acidic soil solution (pH ~ 3.5) through a process not yet understood. The soil distributions indicate that some freshwater lakes are former saline lakes. They are invaded by freshwater after destruction of the sandy loam green horizons, then the freshwater becomes enriched in K +, SO 4 2 −, Fe, Al, and a stream of minor and trace elements. The formation of these green sandy loam horizons in the saline environment and their destruction in the non-saline one emphasizes the dynamic nature of this environment.

Population Genetic Study of Mitochondrial DNA in Roseate Spoonbill (Aves; Platalea ajaja) Breeding Colonies from the Pantanal Wetlands, Brazil

Five breeding colonies of the Roseate spoonbill (Aves: Platalea ajaja) from two Brazilian wetland areas (Pantanal and Taim marshes) were sampled, and domain I of the mitochondrial DNA control region (483 bp) was sequenced in 50 birds. The average haplotype diversity (h = 0.75, s = 0.071) and average nucleotide diversity (pi = 0.004, s = 0.003) were evaluated, and nonsignificant differences were found among the colonies studied. The lack of differentiation among breeding colonies revealed by AMOVA analysis was explained either as a consequence of high gene flow or recent expansion. The significantly negative results of the neutrality tests (Fu's F ( s ) = -23.271, P < 0.01; Tajima's D = -1.941, P < 0.01) associated with the star shape of the haplotype tree and mismatch distribution data are evidence supporting the idea that these populations underwent a recent demographic expansion in the Pantanal region. The average time since the expansion is estimated to be 25,773 years, and this agrees with a period of increased moisture that occurred during the last glacial period.

Influence of area, habitat and water chemistry on richness and composition of macrophyte assemblages in southern Brazilian wetlands

AbstractQuestions: Two hypotheses were tested: (1) physical features, such as wetland surface area and habitat diversity, together with water chemistry, are important determinants of species richness and composition of macrophyte assemblages and (2) species richness and composition of macrophyte assemblages differ between wetlands of different types (i.e., palustrine versus lacustrine) and between wetlands of different hydrologies (i.e. permanent versus intermittent).Location: A subtropical coastal plain segment (2500 km2) of southern Brazil.Methods: Quarterly collections were carried out in 15 wetlands (2004–2005) in southern Brazil. Differences in richness over time were tested using repeated measures ANOVA. Stepwise multiple regression was performed to investigate relationships between total richness and environmental variables. Significance of differences between wetland types and hydroperiods on species composition was verified by MRPP (Multi‐Response Permutation Procedure). The influence of the environmental variables on species composition was assessed using CCA (Canonical Correspondence Analysis).Results: Macrophyte species richness changed with time, was not significantly different between wetland types, but was higher in permanent wetlands than in intermittent ones. Area, habitat diversity and soluble reactive phosphorus concentration explained 76% of the variation in species richness. Species composition was different between permanent and intermittent wetlands, although it was not significantly different between wetland types. Area, habitat diversity and water chemistry explained 50.1% of species composition.Conclusions: Species richness and composition of wetland macrophytes were mainly determined by area, habitat diversity and hydroperiod. These results can be used for the development of conservation and management programs in southern Brazil.

Feeding habits of Noctilio albiventris (Noctilionidae) bats in the Pantanal, Brazil

The lesser bulldog bat, Noctilio albiventris, and the greater bulldog bat, N. leporinus (Noctilionidae) occur from Mexico to Argentina and Uruguay and are known to forage over water courses and ponds (Hood and Pitocchelli, 1983; Hood and Jones, 1984; Fenton et al., 1993; Kalko et al., 1998; Nogueira and Pol, 1998). Noctilio albiventris (20–40 g) feeds mainly on insects whereas N. leporinus (45–90 g) primarily eats fish, but both species are able to feed on insects and fish (Howell and Burch, 1974; Hood and Pitocchelli, 1983; Hood and Jones, 1984; Lewis-Oritt et al., 2001; Bordignon, 2006). Noctilio albiventris often captures insects in the air but notably gleans them from water surfaces (Kalko et al., 1998; Nogueira and Pol, 1998). Compared to other Neotropical insectivorous bats, N. albiventris prey upon a wider variety of insect orders and a wider range of prey size (Aguirre et al., 2003). Although most available data do not indicate herbivory for N. albiventris, seeds of Brosimum and Morus (Moraceae) and pollen of Ceiba (Bombacaceae) have been recorded in their faeces or stomachs (Howell and Burch, 1974). Data on N. albiventris feeding habits, however, are very scarce and limited to Central America and only Bolivia in South America (Hooper and Brown, 1968; Howell and Burch, 1974; Whitaker and Findley, 1980; Aguirre et al., 2003). Here, we studied food items recorded from faecal samples of N. albiventris in three sites in the Pantanal wetlands in Brazil. We describe orders of insects, and plant species (seeds and pollen) consumed by this bat.

An ecological economics approach to estimate the value of a fragmented wetland in Brazil (Mato Grosso do Sul state)

The Upper Paraná River floodplain is the last lotic stretch of an ecosystem seriously threatened given that circa 50% of the original ecosystem has been converted into reservoirs. To assess the recreational value of the Upper Paraná River floodplain, 174 tourists were interviewed using the Willingness to Pay--WTP and Travel Cost--TC methods. The annual aggregated WTP attributed by tourists was US$ 122.50 million and the variables which determine the decision in willingness to pay for the Floodplain are: 'consider oneself as a Floodplain natural resources consumer' and 'marital state'. If the single person considers her/himself as a consumer of floodplain natural resources, the WTP increases by a multiplicative factor of 38.8. The value aggregated by the TC method was US$ 234 millions and decreased by zone as the distance increases. Higher income and traveling farther increases the travel cost, which is inversely related to annual trip frequency. The total recreational value (356.5 millions per year) is high and representative since it refers to an environment fragmented by dams and with many anthropogenic effects. Therefore, the progressive changes on the landscape are a threat to local tourism, since half of the visitors are attracted solely by the scenic beauty, thereby overtaking those factors considered more important by public decision makers and managers, such as recreational fishery or boating.

Benthic invertebrate assemblages and species diversity patterns of the Upper Paraguay River

This paper presents the first study of the benthic invertebrate assemblages of the upper section of the Paraguay River, a major tributary to the Pantanal wetland in Brazil. Thirty-eight sites were sampled along a 200 km section below the city of Cáceres in November 2000. Sixty-nine species and morphospecies were identified, which were dominated by Oligochaeta and Chironomidae. Mean density of benthic invertebrates varied between 72 and 10 354 m−2 in the meandering sector of the river, 3611–49 629 m−2 in the straight–transitional sectors, 682–5962 m−2 in the floodplain lakes, and 1704–2208 m−2 in floodplain channels. Highest densities were attained in sand-gravel sediments dominated by the psammophilous oligochaete Narapa bonettoi. The Shannon diversity index ranged from 0.75 to 2.08 and was highest in floodplain lakes. Statistical analysis (UPGMA and CCA) revealed that benthic assemblages in the floodplain habitats were clearly distinct from the riverine habitats. In the river channel, the habitats were distinguished by grain size while the floodplain habitats were mostly determined by current and silt-clay concentration (floodplain channels) or by organic matter concentration (floodplain lakes). Conservation efforts in the Upper Paraguay area should aim to maintain the flood pulse as a permanent source of spatial and temporal habitat heterogeneity. Copyright © 2005 John Wiley & Sons, Ltd.

Analysis of extinction in ultraviolet and visible spectra of water bodies of the Paraguay and Brazil wetlands

The extinction spectra in ultraviolet and visible radiation were analyzed using filtered and unfiltered water samples obtained in 11 open water bodies in the Ñeembucù (Paraguay) and Pantanal (Brazil) wetlands. The role of dissolved and suspended matter in the total extinction was analyzed between 260 nm and 700 nm. The chromophoric dissolved organic matter (CDOM) was the major component in extinction of considered ultraviolet radiation (260–400 nm). The differences in CDOM concentrations explained the main pattern of extinction of the ultraviolet radiation in the samples. Nevertheless, differences between the studied water bodies were found also to depend on the rate of photodegradation and photobleaching. The methodology developed in the present study was to distinguish “humic optic waters” according to quantity and quality of dissolved and suspended matter present. In the “humic optic water”, the penetration of 10% of incident UV radiation and the photoactive layer are estimated. The influence of particulate matter increases in the total extinction of the wavelengths higher than 400 nm. The integral of the extinction curve of suspended matter in the visible wavelengths (400–700 nm) was found to relate with the total suspended solids and chlorophyll concentrations.

Parasite removal by natural wastewater treatment systems: performance of waste stabilisation ponds and constructed wetlands

Parasite removal and low cost systems for wastewater treatment have become increasingly important requirements in developed and developing countries to safeguard public health from wastewater-associated intestinal diseases. Pilot and field-scale ponds and wetlands in Brazil and Egypt have been investigated for the fate and removal of eggs of human intestinal parasites from domestic wastewater. In northeast Brazil, parasite removal was investigated for a series of five waste stabilisation ponds treating raw wastewater. In Egypt, parasite removal was studied for Gravel Bed Hydroponic constructed wetlands treating partially treated wastewater. Influents to ponds and wetlands contained a variety of parasite helminth eggs (e.g. Ascaris, hookworm, Trichuris, and Hymenolepis spp.). The ponds consistently removed parasite eggs though rate of removal by individual ponds may have been related to influent egg numbers and extent of short-circuiting. Parasite eggs were reduced on average by 94% and 99.9% in the anaerobic and facultative ponds respectively. No eggs were found in effluent from the second maturation pond. In the wetland system, parasite removal varied with reedbed length. The majority of parasite eggs were retained within the first 25 m. Parasite eggs were reduced on average by 98% after treatment in 50 m beds and completely removed after treatment in 100 m beds.

Geochemistry of water and ground water in the Nhecolândia, Pantanal of Mato Grosso, Brazil: variability and associated processes

A distinctive feature of the Nhecolândia, a sub-region of the Pantanal wetland in Brazil, is the presence of both saline and freshwater lakes. Saline lakes used to be attributed to a past arid phase during the Pleistocene. However, recent studies have shown that saline and fresh water lakes are linked by a continuous water table, indicating that saline water could come from a contemporary concentration process. This concentration process could also be responsible for the large chemical variability of the waters observed in the area. A regional water sampling has been conducted in surface and sub-surface water and the water table, and the results of the geochemical and statistical analysis are presented. Based on sodium contents, the concentration shows a 1: 4443 ratio. All the samples belong to the same chemical family and evolve in a sodic alkaline manner. Calcite or magnesian calcite precipitates very early in the process of concentration, probably followed by the precipitation of magnesian silicates. The most concentrated solutions remain under-saturated with respect to the sodium carbonate salt, even if this equilibrium is likely reached around the saline lakes. Apparently, significant amounts of sulfate and chloride are lost simultaneously from the solutions, and this cannot be explained solely by evaporative concentration. This could be attributed to the sorption on reduced minerals in a green sub-surface horizon in the “cordilhieria” areas. In the saline lakes, low potassium, phosphate, magnesium, and sulfate are attributed to algal blooms. Under the influence of evaporation, the concentration of solutions and associated chemical precipitations are identified as the main factors responsible for the geochemical variability in this environment (about 92% of the variance). Therefore, the saline lakes of Nhecolândia have to be managed as landscape units in equilibrium with the present water flows and not inherited from a past arid phase. In order to elaborate hydrochemical tracers for a quantitative estimation of water flows, three points have to be investigated more precisely: (1) the quantification of magnesium involved in the Mg-calcite precipitation; (2) the identification of the precise stoichiometry of the Mg-silicate; and (3) the verification of the loss of chloride and sulfate by sorption onto labile iron minerals.

Flooding‐tolerant legume symbioses from the Brazilian Pantanal

Summary Nodulated legumes in some of the flooded and seasonally flooded areas of the Pantanal Mato‐Grossense wetlands in Brazil are described here. In the permanently flooded lakes (baias) of the Caracara national park Discolobium pulchellum, Mimosa pellita, Sesbania exasperata and Vigna lasiocarpa (syn. Phaseolus pilosus) were the most abundant, whereas close to Corumbá, at the edges of the river Paraguai, Neptunia spp. were also common. Adaptations that allow these legumes to fix N2 in a flooded environment included a floating growth habit, aerenchyma and nodulated adventitious roots. By contrast, Aeschynomene spp. (A. ciliata, A. denticulata, A. fluminensis, and A. sensitiva) were the dominant nodulated legumes in the seasonally flooded pastures of Nhumirim. Stem‐nodulation was commonly observed, particularly on seasonally flooded Aeschynomene and seasonal/permanently flooded Discolobium spp., but also, in a modified form, on floating stems of V. lasiocarpa. The structures of stem and/or root nodules on Aeschynomene spp., Discolobium leptophyllum and V. lasiocarpa are described in detail, and nodulation by D. leptophyllum and Neptunia pubescens is reported for the first time.

On the Use of the Time Axis for Ecological Separation: Diel Rhythms as an Evolutionary Constraint

On the Use of the Time Axis for Ecological Separation: Diel Rhythms as an Evolutionary Constraint

Tolerance to hypoxia and anoxia in neotropical species

This essay presents a synthesis of the main aspects of wetland ecology, emphasizing Brazilian systems. Problems regarding the definition of these areas are discussed, and historical considerations on their use humans are presented. The phenomenon of flooding and drought is considered, in an ecological context, as the principal agent interrupting the successional process, which in these ecosystems is notably maintained in its initial stages. The role of flooding and drought as ecological stress factors for wetland communities is also discussed. In Brazilian wetlands, organisms are adapted at different levels to flood and drought conditions. Plant communities contain many r-strategist species, characterized by their capacity to produce many seed and by their high rate of short-term primary productivity. Special attention is given to the river-floodplain system, as one of the most important wetland systems in Brazil. The role of the flop pulse in the community dynamics of these systems, emphasizing especially the plant communities (phytoplankton, aquatic macrophytes, and floodplain forest), is discussed.

TOLERANCE TO HYPOXIA AND ANOXIA IN NEOTROPICAL TREE SPECIES

O estresse decorrente da saturacao hidrica do solo tem forte carater seletivo. O limite as trocas gasosas do solo com a atmosfera e o rapido consumo do oxigenio presente na agua por raizes e microorganismos geram hipoxia ou anoxia no solo. Isto afeta a respiracao de raizes, microorganismos. e as caracteristicas fisico-quimicas edaficas. A frequencia e a duracao do alagamento determinam a distribuicao espacial das especies, resultando em diferencas floristicas e fisionomicas entre, e.g., as matas de brejo, riparias, mesofilas semideciduas, de varzea e de igapo. A especificidade de habitat das poucas higrofilas exclusivas ou preferenciais contrasta com sua ampla distribuicao geografica. Sob hipoxia ou anoxia, a capa­cidade das raizes desenvolverem atividades vitais das plantas, depende da manutencao de um metabolismo respiratorio. aerobico ou anaerobico, que gere um pool minimo de nucleotideos fosfatados e mantenha a carga energetica acima do nivel critico. A diversidade de respostas morfologicas, anatomicas. fisiologicas e metabolicas a hipoxia/anoxia em plantas neotropicais, dificulta a definicao de tolerância ao estresse. Estas respostas evoluiram concomitante e complementarmente. Logo, a compreensao da estrategia adaptativa de uma dada especie sob inundacao exige uma abordagem integrada, incluindo estudos de demografia e dinâ­mica populacional. Esta e uma revisao do estado atual do conhecimento sobre as estrategias de tolerância a inundacao em plantas neotropicais,

Adaptations to flooding by tropical trees: morphological and anatomical modifications

This essay presents a synthesis of the main aspects of wetland ecology, emphasizing Brazilian systems. Problems regarding the definition of these areas are discussed, and historical considerations on their use by humans are presented. The phenomenon of flooding and drought is considered, in an ecological context, as the principal agent interrupting the successional process, which in these ecosystems is notably maintained in its initial stages. The role of flooding and drought as ecological stress factors for wetland communities is also discussed. In Brazilian wetlands, organisms are adapted at different levels of flood and drought conditions. Plant communities contain many r-strategist species, characterized by their capacity to produce many seeds and their high rate of short-term primary productivity. Special attention is given to the river-floodplain system, as one of the most important wetland systems in Brazil. The role of the flood pulse in the community dynamics of these systems, emphasizing especially the plant communities (phytoplankton, aquatic macrophytes, and floodplain forest, is discussed.

Epidemiological survey of infection with hepatitis B virus in the savannah and wetlands (Pantanal) of central Brazil

Epidemiological survey of infection with hepatitis B virus in the savannah and wetlands (Pantanal) of central Brazil

The mercury problem in the Amazon due to gold extraction

The environmental impacts caused by the use of mercury (Hg), as a gold (Au) amalgam, in gold extraction in three geographical areas located in the Brazilian wetlands (Poconé) and the Amazon (Alta Floresta and Itaituba), are reviewed and solutions proposed.

The role of cultural diversity and communal participation in wetland management in Brazil

This article compares the livelihood strategies of two populations living in different Brazilian wetlands: the fishermen of the coastal floodplain of Marituba, at the mouth of S. Francisco River and the rubber-tappers of the Guaporé Valley. Both communities utilize the renewable resources of the wetlands on a traditional basis: fishery, small-scale agriculture and handicraft in Marituba, and latex, Brazilian nuts and fishery in Guaporé Valley. Both communities are in the process of rapid and intense socioeconomic and biological change. In Marituba, the sugar-cane plantations and the capital-intensive irrigation schemes are threatening the existence of the varzea (floodplain); in Guaporé, rapid deforestation is threatening the livelihoods of local communities. The reaction of these communities is similar: both are fighting for the conservation of the wetland ecosystems as conditions for the survival of their culture and way of life.

Short term nitrogen dynamics in a small Brazilian wetland (Lago Infernão, São Paulo)

ABSTRACTWe have studied a number of related processes of the nitrogen cycle in a Brazilian floodplain lake to identify the major pools and pathways over a short time period. The study was centred on the littoral zone dominated by the floating plantEichhornia azurea, which has a large epiphyte algal community of which heterocystous cyanobacteria were the major components. The water column was continuously undersaturated with oxygen although some elevated values (to 60% saturation) were recorded in the macrophyte beds in the afternoon. Marked diel temperature changes were documented. NH4-N dominated the dissolved N component in the water with maximal values (60 mg m−3) at lowest O2, concentrations early in the morning. Nitrogen fixation (acetylene reduction) of the epiphyte community showed marked diel changes with daily values of 5 mg N fixed m−2day−1(based on 3:1 C2H4:N2ratio). Macrophyte NH4-N uptake rates (in situincubations) were 93 mg N m−2day−1. The activities of nitrifying bacteria could not be detected with the nitrapyrin block on dark CO2fixation but denitrification (acetylene block technique) was recorded in the sediments when enhanced with NO-3. The major pathways of aquatic nitrogen involved macrophyte uptake and sediment release of NH4-N.