Embrapa Pantanal

Corumbá, Brazil

Embrapa Pantanal

Corumbá, Brazil
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Evans T.L.,University of Victoria | Costa M.,University of Victoria | Tomas W.M.,Embrapa Pantanal | Camilo A.R.,Embrapa Pantanal
Remote Sensing of Environment | Year: 2014

This study uses 50. m spatial resolution, dual-season, HH and HV L-band ALOS/PALSAR, and HH and HV C-band RADARSAT-2 data, as well as a comprehensive set of ground reference points, to map the diverse habitats of the hydrologically variant subregions of the Pantanal by using a hierarchical object based image analysis approach. First, mean and standard deviation values of image object training sites were evaluated, and used as the basis for forming preliminary land cover class thresholds for each subregion. Then, a combination of additional refined thresholds, hierarchical rules, and a supervised nearest neighbor algorithm (eCognition Feature Space Optimization) employing several features as primary inputs (mean, standard deviation, seasonal change detection, brightness, maximum difference, area, roundness, brightness, compactness, shape index, and length/width) was utilized, resulting in the definition and classification of ten habitat classes: Forest/Woodland, Riparian Forest, Open Wood Savanna, Open Wood Savanna subject to prolonged flooding, Open Grass Savanna, Agriculture, Swampy Grassland, Swampy Mixed Savanna, Vazantes, and Water. This classification was achieved with an overall accuracy of 80% for the entire Pantanal. The produced habitat spatial distribution maps will provide vital information for determining refuge zones for terrestrial species, and connectivity of aquatic habitats during the dry season, as well as providing crucial baseline data to aid in monitoring changes in the region, and to help define conservation strategies for habitat in this wetland. © 2014 Elsevier Inc.

Pauvolid-Correa A.,Instituto Oswaldo Cruz | Pauvolid-Correa A.,Centers for Disease Control and Prevention | Campos Z.,Embrapa Pantanal | Juliano R.,Embrapa Pantanal | And 3 more authors.
PLoS Neglected Tropical Diseases | Year: 2014

A recent study reported neutralizing antibodies to West Nile virus (WNV) in horses from four ranches of southern Pantanal. To extend that study, a serosurvey for WNV and 11 Brazilian flaviviruses was conducted with 760 equines, 238 sheep and 61 caimans from 17 local cattle ranches. Among the tested equines, 32 were collected from a ranch where a neurologic disorder outbreak had been recently reported. The sera were initially screened by using a blocking ELISA and then titrated by 90% plaque-reduction neutralization test (PRNT90) for 12 flaviviruses. Employing the criterion of 4-fold greater titer, 78 (10.3%) equines were seropositive for Ilheus virus, 59 (7.8%) for Saint Louis encephalitis virus, 24 (3.2%) for WNV, two (0.3%) for Cacipacore virus and one (0.1%) for Rocio virus. No serological evidence was found linking the neurological disease that affected local equines to WNV. All caimans and sheep were negative by blocking ELISA for flaviviruses. There were no seropositive equines for Bussuquara, Iguape, Yellow fever and all four Dengue virus serotypes. The detection of WNV-seropositive equines in ten ranches and ILHV and SLEV-seropositive equines in fourteen ranches of two different sub-regions of Pantanal is strong evidence of widespread circulation of these flaviviruses in the region. © 2014.

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.

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.

Campos Z.,Embrapa Pantanal | Mourao G.,Embrapa Pantanal | Coutinho M.,Instituto Chico Mendes Of Conservacao Da Biodiversidade Base Ran | Magnusson W.E.,National Institute of Amazonian Research
PLoS ONE | Year: 2014

We studied growth of the caiman, Caiman crocodilus yacare, in the Brazilian Pantanal for 27 years between 1987 and 2013.We recaptured 647 of 7769 C. c. yacare initially marked in an area of 50 km2, in two ranches. We were able to determine size at age accurately for 24 male and17 female caimans that had been marked at hatching or less than 1 year old, and recaptured over periods of 5 to 24 years. The other 606 caimans were used to evaluate short-term growth rates. Age-size relationships were estimated using growth models from the Richards family of curves (full model, von Bertalanffy and monomolecular). The form of the relationships differed between analyses based on caimans of known age and analyses based on integration of growth rate on size relationships for caimans whose ages were not known. Individuals showed large variation in short-term growth rates, but data on known-age animals indicated little between-individual variability in longterm growth rates. There was evidence of a small effect of rainfall, but not temperature, on short-term growth of small caimans, but most variation in growth rates was unexplained by variables other than age and sex. Data on known-age individuals indicated that female C. c. yacare generally reach sexual maturity between 10 and 15 years of age. Because of the asymptotic relationship between age and size, deviations of observations from the model for age are larger than for size, and estimates of age at a given size have greater errors than estimates of size at a given age. Integration of growth rate on size relationships may be adequate for estimating size from age in many cases, but accurate estimates of age from size require data on known-age individuals over the size range of the species. © 2014 Campos et al.

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.

Araujo Jr. J.P.,São Paulo State University | Nogueira M.F.,Embrapa Pantanal | Duarte J.M.B.,São 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.

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).

Campos Z.,Embrapa Pantanal | Mourao G.,Embrapa Pantanal
Journal of Natural History | Year: 2015

Camera traps were set up in forest nests in 2009, 2010 and 2012 to capture images of possible predators eating eggs of the Pantanal caiman, Caiman crocodilus yacare. We monitored 57 caiman nests; 42 nests were opened and the eggs were counted (mean = 25 eggs/nest, SD = 4.3). Females were present and captured at 38 of those nests. The remaining 15 nests were used as controls, and we did not capture the females or open the egg cavities of these nests. Most of the nests had the eggs eaten by predators, in both the disturbed group (38 nests) and the control group (13 nests). The main predators were carnivorous mammals, such as crab-eating foxes (Cerdocyon thous), coatis (Nasua nasua) and tayras (Eira barbara), although feral pigs (Sus scrofa) and armadillos (Dasypus novemcinctus) were also photographed eating caiman eggs. The lizard Salvator merianae was photographed eating eggs of two nests. © 2014 Taylor & Francis.

Desbiez A.L.J.,Royal Zoological Society of Scotland | Santos S.A.,Embrapa Pantanal | Alvarez J.M.,Royal Zoological Society of Scotland | Tomas W.M.,Embrapa Pantanal
Mammalian Biology | Year: 2011

The impact of livestock grazing on native wildlife remains a topic for considerable debate. In the Brazilian Pantanal extensive cattle ranching has been practised since the mid-18th century and cattle live alongside a diverse group of medium to large sized terrestrial mammalian herbivores. This study examined the use, similarity and selection of forage resources among cattle (Bos indicus), pampas deer (Ozotoceros bezoarticus) and capybara (Hydrochoerus hydrochaeris) in a paddock in the central region of the Brazilian Pantanal. Plants consumed were identified through micro-histological analysis of faecal samples collected from three species over several seasons, and quadrats (0.5. m. × 0.5. m) were allocated to patches within each of the main landscapes to measure availability of resources. Overall, cattle were classified as grazers, capybara as mixed feeders, pampas deer as browsers. 126 plants were identified in faecal samples of the three species. Similarity indices were highest between domestic cattle and the capybara and lowest between these two species and the deer. Diets were more similar between the species during the wet season (period of resource abundance) than during the dry season (period of resource scarcity). Overall animals selected different forage species H. amplexicaulis and L. hexandra were the only plants selected by all three herbivores. In this study, the presence of cattle does not appear to be as detrimental to wild herbivores as suggested by other examples in the literature. © 2010 Deutsche Gesellschaft für Säugetierkunde.

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