Climate change poses a critical threat to the Pantanal, the largest wetland in the world. Models indicate an increase in the frequency of extreme precipitation events and extended periods of drought. These changes can amplify consequences for Pantanal’s ecological functioning, which has already experienced intensive human modification of its hydrological system and environmental health. The present study analyzed the spatial and temporal dynamics of rainfall and resulting extremes in the Brazilian area of the Upper Paraguay River Basin (UPRB) along with a co-evaluation of the global Sea Surface Temperature data (SST). The predicted results indicate that wet extreme precipitation events will become more frequent in the highlands, while severe and prolonged droughts triggered by warming SSTs in the Northern Hemisphere (North Atlantic and North Pacific oceans) will affect the Pantanal. The linear relations between precipitation with SST of very specific oceanic regions and even from specific oceanic indexes obtained in the present study significantly improve the forecasting capacity, mainly from a resulting reduction to two months of the lead-time between SST warming to concomitant precipitation impacts, and by explaining 80% of Pantanal´s precipitation variation from major oceanic indexes (e.g., ENSO, PDO, NAO, ATL3). Current SST trends will result in inter- and intra-annual flooding dynamic alterations, drastically affecting the Pantanal ecosystem functioning, with consequences for wildlife diversity and distribution. Regarding the foreseeable global climate and land use change scenarios, the results from the present study provide solid evidence that can be used at different decision-making levels (from local to global) for identifying the most appropriate management practices and effectively achieving sustainability of the anthropic activity occurring in the Pantanal.
The Pantanal is the largest wetland of the world and one of the most important biodiversity hotspots in South America. An unprecedented ongoing megadrought is severely affecting its ecological functioning, flood pulse dynamics, and fire regime. Regarding this problematic, the present study generates reliable information about the following key issues: 1—Evolution and dynamics, 2—Origin and determinants, and 3—Forecast based on identified determinants and current trends. Results show that the evolution of the megadrought has been differentiable in both, space and time. As for its origin and determinants, Climate Change was ratified as one of the most important threats to the Pantanal, and to vast areas of South America, since a strong correlation was identified between megadrought’s dynamics and the occurrence of intense marine heatwaves at Northern Hemisphere oceanic waters, and more specifically, at the Northeast Pacific. Results also show that the megadrought is expected to continue at both the Pantanal and the surrounding Highlands, at least until December 2023. Thus, an intensification of fires risk, extending now to areas historically flooded or perhumid should be expected, concomitantly to a very negative impact on non-fire-resistant vegetation cover, as well as ecosystem functioning and biodiversity, perhaps even worse than those from 2020, widely covered by the international media.
24 April 2023 in Natural Hazards and Earth System Sciences
Extreme El Niño events stand out not only because they have powerful impacts but also because they are significantly different from other El Niños. In Ecuador, such events are accountable for negatively impacting the economy, infrastructure, and population. Spatial–temporal dynamics of precipitation anomalies from various types of extreme El Niño events are analyzed and compared. Results show that for eastern Pacific (EP) and coastal Pacific (COA) El Niño types, most precipitation extremes occur in the first half of the second year of the event. Any significant difference between events becomes more evident at this stage. Spatially, for any event, 50 % of all extreme anomalies occurred at elevations < 150 m. The difference between events was significant when considering the altitude when reaching 80 % of all extreme anomalies: the eastern Pacific (EP) El Niño from 1997/98 (EP98) at 500 m, the El Niño from January to April 2017 (COA17) at 800 m, and the EP El Niño from 1982/83 (EP83) at 1000 m. Nevertheless, in some sectors of the Andean Cordillera, the El Niño–Southern Oscillation (ENSO) signal could be detected at 3200–3900 m. The distance to the coastline and the steepness of relief may play a determining role. At lowlands, anomalies are most severe in regions where the seasonality index is the highest. These results are useful at different decision-making levels for identifying the most appropriate practices reducing vulnerability from a potential increase in extreme El Niño frequency and intensity.
Anuran calling behaviour is determined by environmental, endogenous, and social factors. The effect of these factors usually differs among and within species. We used acoustic monitoring to evaluate the effects of environmental predictors on the daily occurrence and call production of Elachistocleis matogrosso (Microhylidae) in the northeastern Brazilian Pantanal. We monitored the calling behaviour of the species over a complete annual cycle at four acoustic monitoring stations. Daily occurrence was positively associated with high minimum air temperature at all sites, and was also related to days with high abundant rainfall at two sites. This result suggests that the minimum temperature acts as the main trigger initiating calling activity in this species. In contrast, call production was positively related to rainfall and accumulated rainfall over the previous three days, with no effect of air temperature. This observation could be related to a high abundance of calling males after some rainy periods, when more water bodies are available for reproduction. Our findings reveal the importance of performing studies at different spatial-temporal and calling scales because the effects of environmental predictors on anuran calling behaviour may differ among sites, and this factor is also important when analysing daily occurrence or call production.
Folivory in bats has been described as chewing bits of leaves to extract the liquids, and then discarding the remaining fibers in form of oral pellets. At least eight species of Neotropical fruit-eating bats have been reported to use folivory as a strategy potentially to provide bats with vitamins, micronutrients and proteins usually scarce in fruits, as well as secondary metabolites that stimulate or inhibit reproductive processes, or even as a supply of water. All reported cases of folivory in bats consist of short, descriptive natural history notes with few supporting details. In depth understanding of leaf consumption by bats is lacking. To bridge this gap, we studied two colonies of Artibeus living under different conditions in the Venezuelan Andes: an urban colony (A. lituratus) and a forest colony (A. amplus) whose individuals exhibited folivorous habits. We hypothesized that bats: (1) feed on leaves from many plant species, and more frequently eat certain plant species over others, (2) show monthly variation in leaf consumption, (3) eat specific parts of each leaf and discard the rest, and (4) within a plant species, eat the same part of each leaf. We collected leaves found below the roosting site of the colonies of both species and analyzed digital images of each leaf to quantify the consumed area. All leaves (n = 1,188) were classified and quantified in terms of the pattern of observed consumption (apical, basal, other). We found that both species of bats fed on leaves from certain plant species over others, showed monthly variation in leaf consumption, and on average consumed less than 50% of the leaf, equivalent to an area of 5–7 cm2 (n = 655). Maximum consumption of leaves was observed in both species in the weeks immediately prior to males exhibiting scrotal testes and females becoming palpably pregnant. Results from our study provide the first systematic and detailed assessment of folivory in bats, showing the use of leaves all year long by two bat species. Future research should investigate whether males and females consume leaves to the same extent, and on the chemical properties of consumed plant species.