Brazilian Pantanal Research Articles

Characteristics of Extreme Meteorological Droughts Over the Brazilian Pantanal Throughout the Xxi Century

Characteristics of Extreme Meteorological Droughts Over the Brazilian Pantanal Throughout the Xxi Century

Seasonal changes in taxonomic and functional diversity of lizard communities in southern Brazilian Pantanal

Seasonal changes play a key ecological role, structuring biotic processes and communities. Yet we generally lack an understanding of how seasonal flood regimes affect communities in floodplains. Herein, we investigated the effects of seasonal changes in taxonomic and functional diversity of lizard communities in southern Pantanal ecoregion. Lizards were sampled in seven sites encompassing seasonally flooded grasslands and dense arboreal savannas, across rainy and dry seasons (2005-2006). Functional diversity metrics were based on three morphological traits and included intraspecific variability. We collected a total of 810 lizards from 13 species. Species richness did not differ across seasons or months. Lizard abundance varied among sampling months, but did not differ between rainy and dry season. Low values of abundance were recorded at drawdown period. Community composition did not vary between seasons. Functional diversity metrics exhibited random distributions, and both functional richness and evenness were not influenced by seasons. Although communities seem to be resilient to seasonal variations, our findings highlighted that transition from rainy to dry season may represent an important constraint on lizard abundance. Including traits related to food acquisition and predator avoidance could provide new insights into the effects of seasonal floods on floodplains' lizard communities.

Temperature variation in nests of Paleosuchus palpebrosus (Crocodylia: Alligatoridae) near the southern edge of the species´ range, Brazil.

We monitored the temperature of seven Paleosuchus palpebrosus nests found on the banks of streams surrounding the Brazilian Pantanal, near the southern limit of the species´ distribution, between 2008 and 2013. The mean temperature of the nests between 45 and 68 days incubation, the presumed period of sex determination, varied between 26.1 and 31.5o C. Nest temperatures were 2 to 5°C higher than air temperatures, presumably due to metabolic heat of decay of material within the nests, but air temperature explained 10-50% of the variance in egg-chamber temperatures. The estimated incubation periods for nests from which eggs hatched were 80, 84, 86, 90 and 104 days with a mean of 89 (SD =9.23) days, though these are probably slight overestimates because eggs may have hatched in the period between inspections. For these nests, there was no significant relationship between mean temperature and incubation period (r2 = 0.23, p = 0.411).

The role of unprotected and privately protected areas for ocelot conservation: densities in Colombia and Brazil

AbstractThe ocelot (Leopardus pardalis) is a widely distributed, medium-sized felid in the Americas with declining population size. We estimated ocelot densities and home ranges in one agricultural area in the Magdalena River valley in Colombia, a private reserve and cattle ranch in the Colombian Llanos, and a private reserve in the Serra do Amolar in the Brazilian Pantanal. We used camera trapping (39–52 stations) and spatially explicit capture-recapture (SECR) models. Density estimates (individuals/100 km2) were 11.0 ± 2.7 (SE) in the Magdalena River valley; 13.2 ± 3.2 (SE) in the Llanos, and 10.3 ± 2.9 (SE) in the Serra do Amolar. Overall, despite an impact of agriculture and human disturbance, our results highlight the importance of unprotected areas and privately protected ranching areas for ocelot conservation. As agriculture continues to expand across the tropics causing habitat loss, and negatively affecting ocelot densities, we recommend land use planning and best agricultural practices to maintain natural habitats, thereby limiting human impacts on ocelot conservation.

Seed predation by macaws favors fruits with less seeds and thicker endocarps in the palm Attalea phalerata

When foraging on a specific range of fruits or seeds, animals can represent a natural selection force, affecting plant population realized fecundity. Most studies have focused on characteristics of dispersed seeds, but the higher predation of seeds of specific size or shape is also an important force that influences the populations’ realized fecundity and can help to understand patterns of plants genetic variability. In the Brazilian Pantanal, we investigated the predation of Acuri (Attalea phalerata) palm fruits by macaws, whose seeds go intact through tapirs digestive tract and then are deposited on latrines, where they are often consumed by seed predators. We found 251 fruits, containing between 1 and 5 seeds per fruit; 170 were intact and 81 had been partially damaged by macaws, mostly those containing 3 or 4 seeds per fruit and with thin endocarps. We argue that the higher consumption of fruits with these traits reflects a trade-off in the energy spent by macaws to open the fruits and the energy provided by them. Higher predation on 3-4 seeded fruits favors the selection of 1-2 seeded fruits, revealing a selection force opposed to the one exerted by bruchids and small rodents, which favors multi-seeded palm fruits.

Extensive aquatic subsidies lead to territorial breakdown and high density of an apex predator.

Energetic subsidies between terrestrial and aquatic ecosystems can strongly influence food webs and population dynamics. Our objective was to study how aquatic subsidies affected jaguar (Panthera onca) diet, sociality, and population density in a seasonally flooded protected area in the Brazilian Pantanal. The diet (n = 138 scats) was dominated by fish (46%) and aquatic reptiles (55%), representing the first jaguar population known to feed extensively on fish and to minimally consume mammals (11%). These aquatic subsidies supported the highest jaguar population density estimate to date (12.4 jaguars/100 km²) derived from camera traps (8,065 trap nights) and GPS collars (n = 13). Contrary to their mostly solitary behavior elsewhere, we documented social interactions previously unobserved between same-sex adults including cooperative fishing, co-traveling, and play. Our study demonstrates that aquatic subsidies, frequently described in omnivores, can also transform the ecology and behavior of obligate carnivores.

QUANDO A ESCOLA VIRA O QUINTAL DE CASA: UM ESTUDO DOS JOGOS TRADICIONAIS E DA CULTURA LÚDICA DAS CRIANÇAS PANTANEIRAS

The Escola Fazenda Santa Monica (EFSM) is a bimonthly boarding school in Brazilian Pantanal. The aim of this study is to analyze the traditional games of the children of the EFSM in light of the debate on the playful culture. Therefore, a case study was carried out with a field diary to collect data and provide content analysis to organize, categorize, and analyze these data. Traditional games have been known for a long time (by children and the elderly), in a sociocultural context and have survived over time through intergenerational dissemination (imitation, instruction or collaboration). At EFSM, some of these games, when experienced, maintain their main structure (theme), rules and objectives (form), but others go through adaptations, since resignification is recurrent in children's playful culture. To think about the traditional games of the Pantanal children is to highlight their playful power to transform the institutional space of EFSM in a unique place, where it is possible to express their individualities, socialize, build knowledge and reframe their playful culture.

Selection indexes for Nellore production system in the Brazilian Pantanal

The objective was to develop selection indexes for Nellore cattle raised in full-cycle production system in the Brazilian Pantanal. The resulting offspring are retained as replacements or sold at two years of age. Preliminary analyses explored effects of scale on economic values (EV). However, given the available data, these effects were very small. Presented herein are results from a simulated system consisting of 5,000 cows with all animals maintained on pasture as is typical in Pantanal. The EV were determined by approximating the partial derivatives of the profit function, changing one trait at a time, by one unit, while keeping the other traits constant. Traits in the breeding objective were mature cow weight, direct and maternal weaning weight, postweaning average daily gain, subcutaneous fat depth, longissimus muscle area, and stayability. Economic values were calculated on the basis of number of animals (per head), number of animal units, and arroba of carcasss weight. Regardless of the basis, maternal weaning weight and subcutaneous fat depth made negligible contributions to the breeding objective. Proportions of variation in the breeding objectives (per head, per animal unit, per arroba) explained by cow weight, direct weaning weight, postweaning average daily gain, stayability, and longissimus muscle area were: 13, 13, 17; 6, 1, 5; 3, 3, 4; 67, 67, 61; and 11, 17, 13, respectively. These indexes may aid Nellore breeders in their selection decisions, thus facilitating the genetic progress and increased productivity and profitability of Pantanal herds.

Quantifying bite force in coexisting tayassuids and feral suids: a comparison between morphometric functional proxies and in vivo measurements.

BackgroundMeasuring mammals’ bite force in laboratory conditions is not a simple task, let alone on wild medium-sized mammals in the field. Thus, morphometric-proxies are usually used to infer morphofunctional properties of musculoskeletal features. For instance, the study of bite force-indexes suggests that different capacities to crack food items reduce the competition between coexistent collared and white-lipped peccaries (Pecari tajacu and Tayassu pecari). The presence of exotic feral hogs (Sus scrofa) in peccaries’ endemic areas gives rise to new ecological interactions between them. An example is the Brazilian Pantanal wetland, where ecomorphological mechanisms may play a role in their ecological relations. Taking this scenario as a case of study, we aimed to verify if the morphometric-proxies are de facto reliable tools, by comparing bite forces-indexes with the in vivo bite forces of these species.MethodsWe captured 21 collared and white-lipped peccaries and feral hogs in the Brazilian Pantanal to assess their bite force at first molar. The Bite Force Measuring Tube (BiTu) is a robust and simple mechanical device designed to be used in field conditions. Only 11 individuals successfully bit the BiTu before being released. Their body measurements were compared and correlated with their bite force. The in vivo bite forces were compared with bite force-indexes of two papers based on independent morphometric methods and datasets: Sicuro & Oliveira (2002) used classic morphometrics to infer the bite forces of these three species in the Brazilian Pantanal, and Hendges et al. (2019) used geometric morphometrics to compare bite forces-indexes and feeding habits of the extant peccary species. The results of all species were standardized (Z-curves) according to each method. Doing so, we obtained comparable dimensionless comparable values but maintaining the differences between them.ResultsThe morphometric-proxies-based studies presented similar results: collared peccaries present weaker bites than white-lipped peccaries and feral hogs, while these two species presented no significant differences in their bite force-indexes. The in vivo bite force results suggest the same relations predicted by the morphometric models, including the high variation among the feral hogs. We found a significant correlation between the individuals’ weight (kg) and their actual bite force (N) but no significant correlations with the head length.ConclusionsThe BiTu proved to be a functional and low-cost tool to measure bite force in field conditions. The in vivo results presented a good correspondence with the predictions based on morphometric-proxies by Sicuro & Oliveira (2002) and Hendges et al. (2019). The results denote that these studies succeed in capturing the biomechanical signal of the three species’ skull-jaw systems. This empirical validation confirms that these morphometric-proxies analyses are reliable methods to ecomorphological and evolutionary inferences.

Methods for the characterization of activity patterns in elusive species: the giant armadillo in the Brazilian Pantanal

AbstractThe behavioral study of elusive species, which often cannot be directly observed in the wild, is based on the use of animal monitoring technologies. Here, we evaluate the performance of four methods applied simultaneously on a single population to detect and characterize the activity behavior of elusive species, using the giant armadillo Priodontes maximus as a model. GPS tagging, accelerometer, and camera trap array data were used to characterize general activity patterns, while camera traps placed in front of burrows in use were used to define activity duration, onset, and termination times. Circular kernel probability density functions were used to characterize activity patterns with each data set and the overlap coefficient Δ4 was used to characterize the similarity between them. We gathered data from 53 armadillos during 9 years in the Pantanal wetlands of Brazil. Activity duration estimates showed significant variation among monitoring methods but were generally short (4.5–6 h on average). Overall, the estimates of activity timing provided by the methods used were relatively similar (>75% Δ4 overlap) and pointed to a nocturnal activity pattern. Armadillos left their burrows mainly in the first hours after sunset, and terminated their activity mainly between midnight and 4 am. However, the camera trap array provided a later activity onset and peak estimates for the species when compared to other methods. The species spends 75–80% of its time underground and accelerometer data shows that armadillos are not active and do not feed while underground, pointing to a fossorial behavior for the species. Although researchers should be aware of the small biases that can emerge from some of the methods, the general similarities among patterns indicates that researchers can choose among the ever‐increasing number of animal monitoring technologies depending on their research question and constraints.

A new species of Chalepides Casey, 1915 (Scarabaeidae, Dynastinae, Cyclocephalini) from the Pantanal of Brazil

Chalepides pantanalensis Ratcliffe & Seidel is described as a new species from the Pantanal region in Brazil. A description, diagnosis for distinguishing the species, illustrations, and a distribution map are provided. The new species is morphologically compared with C. howdenorum Joly & Escalona and C. osunai Joly & Escalona.

Temporal variability in evapotranspiration and energy partitioning over a seasonally flooded scrub forest of the Brazilian Pantanal

Brazilian Pantanal is the largest seasonal wetland in the world and it plays an important role in regulating the local and global water cycle and energy balance. The Pantanal landscape consists of a mosaic of temporary and permanent aquatic habitats, floodable and non-floodable pastures, and forests; however, patterns of energy exchange are poorly understood, especially for seasonally flooded forests. Thus, the main objective of this research was to assess the variability of evapotranspiration (ET) and to evaluate biophysical controls on ET for a seasonally flooded scrub-forest. We used eddy covariance to measure latent (LE) and sensible (H) heat fluxes and linked both micrometeorological and remote sensing data to assess the connection between water dynamics and phenology. Our data suggest that 72% of the net radiation (Rn) was consumed by LE + H, even during the dry season, indicating that trees can access deep water when surface water is limiting. The decoupling factor (0.63 ± 0.08) suggests that the canopy is decoupled from the atmosphere and ET is essentially sensitive to Rn. The patterns of ET and vapor pressure deficit suggest that ET was more dependent on the Rn received and less dependent on stomatal control, but still exhibited a strong relationship with biotic factors such as enhanced vegetation index (EVI), which is sensitive to seasonal variations in leaf area index and canopy cover. Stomatal limitations of this seasonally flooded forest appear to be minimal, even in the dry season, presumably due to the relatively high-water table, the ability of trees to acquire subsurface water, and the predominance of secondary species with high rates of leaf gas exchange. These data indicate that seasonally flooded tropical forests of the Pantanal are consistent sources of water vapor to the atmosphere even during seasonal drought.

Hematological parameters of a Neotropical wild frog population, with a phylogenetic perspective on blood cell composition in Anura.

Hematological parameters can provide key information to an animal health status. However, this information is usually hard to obtain. Here, we described the hematological parameters of Leptodactylus podicipinus in the Brazilian Pantanal. We measured red blood cell morphometrics, erythrogram, and leukogram. We also tested for phylogenetic signal in the erythrogram and leukogram of 48 frog species from 15 families, testing if body size explains their variation. Lymphocytes were the most abundant leukocytes (>60%) in L. podicipinus, followed by neutrophils (∼10%). Given that L. podicipinus is an abundant and widely distributed species in central Brazil, knowing its hematological pattern can help establish a baseline and improve its use as a bioindicator of environmental degradation. Mean corpuscular hemoglobin and value contributed more to the phylomorphospace of erythrogram, in which Leptodactylus spp. and Hypsiboas raniceps had lower values of these variables, whereas Bufotes viridis and Hyla arborea had high values. The phylogenetic signal was spread throughout the dimensions of the leukogram phylomorphospace. The variables that most contributed to it were total leukocytes counts, lymphocytes, and neutrophils. We also found a moderate phylogenetic signal for both the erythrogram and leukogram. Accordingly, body size accounted for a low proportion of variation in both the leukogram (4.7%) and erythrogram (0.57%). By applying phylogenetic comparative methods to hematological parameters, our results add a new perspective on the evolution of blood cell physiology in frogs.

Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, daily rainfall was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

Screening of 20 Pantanal Wetland Plants for Anti-Candida Activity using HPLC-DAD-MS/MS and Bioautography to Characterize Active Compounds

AbstractThe Pantanal wetland harbors a rich flora with uncharted pharmacological potential. This study evaluated 20 Brazilian Pantanal plants against Candida albicans, C. parapsilosis, C. tropicalis, and C. krusei. Fungal susceptibility was determined by agar diffusion and broth microdilution; active compounds were identified by bioautography and HPLC-DAD-MS/MS. Sesbania virgata, Polygala molluginifolia, and Cantinoa mutabilis extracts and their chloroform and ethyl acetate (EtOAc) fractions exhibited the best activity against all Candida species tested. The EtOAc fraction of P. molluginifolia proved to be more efficient in inhibiting C. parapsilosis and C. krusei growth (Minimum inhibitory concentration of 125 and 62.5 μg/mL, respectively). Bioautography of this fraction revealed two active bands, characterized by HPLC-DAD-MS/MS as a mixture of podophyllotoxin derivatives blumenol, besides some flavonoids. This work demonstrated antifungal potential of P. molluginifolia podophyllotoxin derivatives and the versatility of bioautography with HPLC-DAD-MS/MS to identify the bioactive compounds.

Aerial insectivorous bats in the Brazilian Pantanal: diversity and activity patterns in response to habitat and microclimate

Aerial insectivorous bats in the Brazilian Pantanal: diversity and activity patterns in response to habitat and microclimate

Novel gammaherpesvirus associated with primary gastric T-cell lymphoma in a free-ranging giant armadillo in Brazil.

The number of viral-associated neoplasms reported in wildlife has increased over the last decades, likely because of growing research efforts and a potentially greater burden of carcinogenic pathogens. Herein, we describe a primary gastric T-cell lymphoma in one free-ranging giant armadillo (Priodontes maximus) from Brazilian Pantanal infected by a novel gammaherpesvirus, proposed as Cingulatid gammaherpesvirus 1 (CiHV-1). By chromogenic in situ hybridisation against Epstein-Barr virus some neoplastic cells were labeled. Subsequently, a molecular screening was carried out to detect the occurrence of this pathogen in other giant armadillos in the same region. Overall, this novel virus was detected in 14.3% (3/21) of the tested giant armadillos. We suggest this herpesvirus, the first in Xenarthra, as a plausible aetiology of the neoplasm. The implications of CiHV-1 for this species are uncertain; while no outbreaks of disease have been recorded, the present study raises concerns. Further research is warranted to assess the real significance of CiHV-1 and its potential oncogenic role in this species.

Fire tolerance strategies in woody species from Pantanal riparian forests involve phenolic compounds and structure of the inner bark

Fire is common in seasonally dry areas in many parts of the world, and its effects on vegetation in these areas have been well studied. In riparian forests of the Pantanal, where fuel accumulation (dead plants) in the dry season can be a substantial driver of fire occurrence, little is known about the role of bark traits to fire protection in woody plants. Herein we evaluated some physical, chemical and anatomical bark traits to determine if they are associated with fire tolerance in tree riparian species of the Pantanal. To accomplish this, we selected three fire-sensitive species and seven fire-tolerant species in riparian forest of the Paraguay River. Bark samples were analyzed for relative total, outer and inner bark thickness, bark density, concentration of phenolic compounds and tannins, thermogravimetric behavior and their anatomical structure. We observed higher concentration of phenol and tannins and higher percentage of sclerenchyma in bark from fire-tolerant species than fire-sensitive species. Bark of fire-tolerant species also showed more sclerenchyma cells near vascular cambium and higher temperatures of thermal decomposition. In contrast, relative total, outer and inner bark thickness, and bark density did not differ between species groups. The high concentration of phenol and tannins, combined with higher percentage of sclerenchyma in secondary phloem, appear as the major bark traits that could mitigate fire damage in species from riparian forest of the Brazilian Pantanal.

Habitat quality, not habitat amount, drives mammalian habitat use in the Brazilian Pantanal

Habitat quality, not habitat amount, drives mammalian habitat use in the Brazilian Pantanal

Passive acoustic monitoring of the Ferruginous Pygmy-Owl (Glaucidium brasilianum) over a complete annual cycle: seasonality and monitoring recommendations

ABSTRACT Monitoring the vocal behavior of owls is challenging because of their nocturnal habits and limited vocal activity. Here, we evaluated the use of passive acoustic monitoring coupled with automated signal recognition software to monitor the spontaneous vocal activity of the Ferruginous Pygmy-Owl (Glaucidium brasilianum) over a complete annual cycle at five recording stations in the Brazilian Pantanal. The vocal behavior of this species was concentrated during the crepuscular periods, with highest vocal activity in the hours prior to sunrise. The Ferruginous Pygmy-Owl was vocally active throughout the year, but the species showed a peak of activity from June to August. Paired Ferruginous Pygmy-Owl males tend to perform territorial calls less often during the nestling period, which may partly explain the significant decrease in the vocal activity after August. Our results suggest that the breeding period of the species starts in June, and the nesting phase probably occurs from September onwards, when the wet season starts. The first rains in seasonal tropical areas are usually associated with an increase in food availability, which may explain the species´ breeding period onset. Future surveys aiming to monitor the species, avoiding the use of broadcast calls, should be performed before sunrise between June and August, when the vocal activity was maximal.