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Corumbá, Brazil

Araujo Jr. J.P.,Sao Paulo State University | Nogueira M.F.,Embrapa Pantanal | Duarte J.M.B.,Sao Paulo State University
Journal of Wildlife Diseases | Year: 2010

Habitat, fragmentation and diseases have resulted in a decline of the marsh deer (Blastocerus dichotomus) throughout its South American range. Our objectives were to determine whether marsh deer intended for translocation from a region of the Rio Paraná Basin had been infected previously by foot-andmouth disease virus (FMDV) and whether they were carrying virus. We captured marsh deer from June to October 1998 and collected blood from 108 animals and esophageal-pharyngeal fluid from 53. Serum was tested for antibodies against three FMDV serotypes (O, A, and C) by liquid-phase-blocking sandwich enzyme-linked immunosorbent assay (ELISA). Esophagealpharyngeal fluid was tested for FMDV RNA by reverse transcription polymerase chain reaction (RT-PCR) and inoculation into three successive baby hamster kidney (BHK-21) cell subcultures, followed by RT-PCR of cultures. We detected low login titers (range .1.0-1.5) to FMDV subtype A24 Cruzeiro in 19 of 108 sampled marsh deer, but failed to isolate FMDV or detect FMDV RNA in any samples. We conclude that marsh deer from our study site were unlikely to cany FMDV; however, as a preventive measure, the 19 animals with titers for FMDV were not sent to FMDV-free Brazilian states. © Wildlife Disease Association 2010. Source

Oliveira M.D.,Embrapa Pantanal | Hamilton S.K.,Michigan State University | Jacobi C.M.,Federal University of Minas Gerais
Aquatic Invasions | Year: 2010

The bivalve Limnoperna fortunei (Dunker, 1857), also called golden mussel, is native to Asia but becoming dispersed around the world. The golden mussel resembles the invasive dreissenid bivalves in many respects, and although much less studied it evidently has broader environmental tolerances. The golden mussel was introduced into the La Plata River estuary (South America) and quickly expanded upstream to the north, into the tropical Paraguay River reaching a large floodplain area in Brazil known as the Pantanal wetland. The golden mussel tolerates environmental conditions in the Pantanal that would be inhospitable for most bivalves, but mussel mortality has been observed during the most extreme oxygen depletion events. Based on knowledge about the limiting factors for the golden mussel in the Pantanal wetland, its potential distribution was predicted for the remainder of the Paraguay River basin where the species is not present, as well as in other river systems throughout Brazil. Forecasts of potential distribution in Brazilian river systems were based on physicochemical limitations for shell calcification, and specifically on lower thresholds of dissolved calcium concentrations and the calcium carbonate (calcite) index of saturation, which may be a better indicator of calcification potential in low-calcium waters than calcium concentration alone. In addition to examining spatial patterns in calcium and calcification potential, these and other limnological and climate variables were used in ecological niche modeling using GARP and Maxent algorithms. Forecasts of potential distributions in three major North American river systems (Mississippi, Colorado, and Rio Grande) were based mainly on water temperature because calcium availability and calcification evidently would not be limiting to golden mussel establishment in those waters. Due to the greater tolerance of the golden mussel to conditions known to limit other bivalves, as well as its greater ability for shell calcification in low-calcium water, the golden mussel could potentially become broadly distributed throughout Brazil. According to its thermal tolerance L. fortunei could become established in the Mississippi, Colorado and Rio Grande drainage systems, although the northern Mississippi River system including the Missouri River may be too cool in the winter to support the golden mussel. © 2010 The Author(s). Source

Campos Z.,Embrapa Pantanal | Sanaiotti T.,National Institute of Amazonian Research | Magnusson W.E.,National Institute of Amazonian Research
Amphibia Reptilia | Year: 2010

The dwarf caiman, Paleosuchus palpebrosus, is considered one of the smallest crocodilians. However, our surveys indicate that the species regularly reaches larger sizes than usually reported in the literature. Most individuals lose tail tips, and we did not encounter any individual with snout-vent length (SVL) > 70 cm that had an intact tail. P. palpebrosus attains SVL > 112.5 cm (equivalent to a total length with intact tail estimated from SVL of 210 cm) in streams around the Pantanal, 106 cm (198 cm) in flooded forest in central Amazonia, and 100 cm (187 cm) in flooded forest and around the Madeira-Guaporé River. © 2010 Koninklijke Brill NV, Leiden. Source

Campos Z.,Embrapa Pantanal | Magnusson W.E.,National Institute of Amazonian Research
Journal of Thermal Biology | Year: 2013

Body temperatures of 13 Paleosuchus palpebrosus, 7 males and 6 females, were monitored by radio-telemetry during cold periods (dry season) and warm periods (wet and dry seasons) in a stream draining into the Brazilian Pantanal. The mass of the caimans varied from 2.5 to 20.0. kg, and snout-vent length from 47.5 to 95.0. cm. Mean monthly body temperature was 21.6 °C, and varied from 20.1 to 25.6 °C throughout the year. Body temperature was correlated with air and water temperature but did not differ between males and females. Unlike all other crocodilians investigated in detail to date, the caimans did not show evidence of attempts to obtain higher body temperatures when ambient temperatures were low, and had low and generally constant temperatures in relation to the surrounding air and water throughout the year. The caimans remained in burrows during cold periods in the dry season, which may explain why they did not seek higher temperatures. Tolerance of relatively low and constant body temperatures may be a key adaptation of species of Paleosuchus, allowing them to occupy environments inhospitable to other crocodilians. © 2012 Elsevier Ltd. Source

Oliveira M.D.,Embrapa Pantanal | Hamilton S.K.,Michigan State University | Calheiros D.F.,Embrapa Pantanal | Jacobi C.M.,Federal University of Minas Gerais
Wetlands | Year: 2010

Over the past 10 years the golden mussel (Limnoperna fortunei), an exotic species native to eastern Asia, has become widespread and abundant in the Pantanal Wetland, Brazil. Oxygen concentrations are often low in rivers and floodplain waters of the Pantanal and oxygen depletion events can last for several weeks during the rising water phase. Although mortality of L. fortunei has been documented during oxygen depletion events, its tolerance to hypoxic and anoxic conditions is poorly understood, in part because changes in oxygen availability are accompanied by other changes such as decreased pH. We analyzed interannual variation in densities of adults and juveniles in relation to varying oxygen conditions, and tested the tolerance of L. fortunei to oxygen depletion events in a floodplain lake and in the laboratory. Mussels died after 5 days of an oxygen depletion event in a floodplain lake, and a population established there in 2005 was extirpated in 2006 owing to hypoxic conditions. Laboratory tests confirmed that mussels died more quickly in water from the oxygen depletion event. Annual oxygen depletion events must control the density of the invasive golden mussel in the Pantanal, maintaining low densities and periodically extirpating them from some habitats. © 2010 Society of Wetland Scientists. Source

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