Search

The life cycles of bats are constrained by availability of resources such as food and shelter. Disruptions limiting otherwise naturally regulated access to these resources ultimately affect the fitness of bat populations and may eventually lead to local extinctions. We sampled bats before and after an Amazonian mega-dam water filling and retrieved data on their reproductive phenology, testing if and how sex ratio, seasonal abundance, and reproductive patterns respond to impacts of the newly operating hydroelectric dam. We analyzed data from 3,298 bat captures of 49 species. Females outnumbered males, previously and after the dam implementation, and we observed seasonal variations in the abundance of bats, which was lower after the implementation of the dam for most species. All species had at least 1 reproductive peak of pregnancy and/or lactation beginning at a variable time across seasons. Most species and functional ensembles were reproductively bimodal, with exceptions being the polymodal Artibeus obscurus and unimodal Phylostomus elongatus. Operations of the hydroelectric dam affected the abundance of both sexes equally, and effects were stronger in the rainy season, altering the timing of reproduction for females, delaying and shortening pregnancy and lactation. These changes expressed in female reproductive activity may be related to the shortfall of resources because of loss of irreplaceable vegetation caused by the dam filling. As we cannot predict the roles of variation of reproductive patterns observed after the filling in the long run we reinforce the importance of long-term, continuous monitoring and management to safeguard the reestablishment of reproductive patterns of females in order to repopulate and keep bat populations healthy in remaining areas along following dam construction. [ABSTRACT FROM AUTHOR]

Southwestern Amazonia has low spatial coverage of hydro-meteorological data, making climate and hydrological models essential tools. Thus, it is necessary to evaluate these models to verify their suitability for future climate change assessments. We evaluate the ability of a regional climate model (Eta) forced with three Earth system models and a large-scale hydrological model (MGB) to represent hydroclimatic variables for the current climate in the Madeira River basin. Different hydro-meteorological databases are used to evaluate the systematic errors of the coupled model system. The simulation results show that the Eta model underestimates (overestimates) precipitation over the basin during the rainy (dry) season. The hydrological processes simulated by the MGB are considered satisfactory, although the model has some limitations with respect to the timing of floods and their removal in different discharge regimes. [ABSTRACT FROM AUTHOR]

A new loricariin species of Sturisoma is described from the Cautário, Guaporé, Mamoré, Machado and Soteiro rivers, Madeira River basin, in Bolivia and Brazil. The new species is distinguished from its congeners by the presence of a middorsal longitudinal, thin dark brown stripe on the caudal peduncle, extending from two or three plates posterior to the dorsal‐fin base, reaching the origin of the caudal fin, or one or two plates anterior to the origin of the caudal fin; small squarish anteriormost abdominal plates; and a middorsal longitudinal dark‐brown stripe from first predorsal plate to near the dorsal‐fin origin. Furthermore, the new species is diagnosed from congeners by plate morphology, counts on the median series, coalescent plates and ventrolateral thoracic plates, in addition to measurements related to body and head structures. An analysis of genetic distances using cytochrome C oxidase subunit 1 gene marker of the mitochondrial genome between the new species and several congeners is presented, in addition to a likelihood analysis to illustrate the position of the new taxon within Sturisoma. An identification key for species of the genus currently recorded at the upper Amazonas River basin is provided. [ABSTRACT FROM AUTHOR]

Eta Regional Model of CPTEC-INPE is used to obtain intraseasonal (30-day) 8-member ensemble forecasts over the Madeira River basin for the period 2002–2012. The initial and boundary conditions are taken from Atmospheric General Circulation Global Model in six members and from Global Coupled Ocean-Atmosphere Model in two members. The intraseasonal forecasts produced by dynamic downscaling with Eta Regional model ensemble have satisfactory skill. The skill of the ensemble mean is better than the individual members up to 15-days lead time forecasts. The ensemble mean reproduces the seasonal cycle and spatial distribution of the hydrological variables. Members with the relaxation technique of Betts-Miller-Janjic produced better results. The forecasts by the members that used Kain-Fritsch scheme presented larger deviations from observations. Substantial improvements in skill are obtained through bias correction. This is the first work to attempt dynamic downscaling over the Madeira Basin in the intraseasonal time scale for a period of 10 years. The ensemble downscaled products have potential to be fed into surface hydrological models for forecasting droughts and floods and related hydrological variables over the basin. • RCM-Eta satisfactorily reproduces the seasonal variability of hydroclimatic variables. • The ocean-atmosphere coupled model is unable to improve the forecast quality. • Bias correction improves the intra-seasonal forecasts substantially. [ABSTRACT FROM AUTHOR]