Changes in atmospheric circulation and evapotranspiration are reducing rainfall in the Brazilian Cerrado

Here we analyze the trends of rainfall and the frequency of rainy days over the Brazilian Cerrado between 1960 and 2021 in four distinct periods according to the seasonal patterns over the region. We also evaluated trends in evapotranspiration, atmospheric pressure, winds, and atmospheric humidity over the Cerrado to elucidate the possible reasons for the detected trends. We recorded a significant reduction in rainfall and frequency of rainy days in the northern and central Cerrado regions for all periods except at the beginning of the dry season. The most pronounced negative trends were recorded during the dry season and the beginning of the wet season, where we recorded reductions of up to 50% in total rainfall and the number of rainy days. These findings are associated with the intensification of the South Atlantic Subtropical Anticyclone, which has been shifting atmospheric circulation and raising regional subsidence. Moreover, during the dry season and the beginning of the wet season, there was a reduction in regional evapotranspiration, which also potentially contributed to the rainfall reduction. Our results suggest an expansion and intensification of the dry season in the region, potentially bringing broad environmental and social impacts that transcend the Cerrado boundaries.

Conceptual bases in restoration of scientific vertebrate collections

The scientific heritage preserved in Brazilian biological collections has inestimable value. Despite the research on curation and restoration of biological material is regarded as strategic, there is a lack of expertise in these areas in the country. These deficiencies often determine the use of obsolete or even inadequate procedures aimed at the recovery of material for research or exhibition, resulting in risk to valuable specimens. In the present work we provide a review of the literature on the restoration of biological specimens and summarize concepts employed in the restoration of mammals and birds of the Museu Nacional, Universidade Federal do Rio de Janeiro, exhibition in 2011. The aim of this work is to contribute to the development of protocols when interventions are needed to restore damaged specimens.

DNA sequence analysis and the phylogeographical history of the rodent Deltamys kempi (Sigmodontinae, Cricetidae) on the Atlantic Coastal Plain of south of Brazil

The rodent Deltamys kempiThomas, 1917 is found on the Coastal Plain - a recently formed geographic region located on Brazil's south-east coast. Considering that Deltamys is the only South American sigmodontine with a sex chromosome system of type X(1)X(1)X(2)X(2)/X(1)X(2)Y, this investigation was focused on the phylogeographic history of this taxon by using gene sequence analysis, trying to clarify when Deltamys differentiated, what was its centre of diversification, and what were the probable routes it used to reach its present distribution. We analysed sequences of the mitochondrial cytochrome b gene and nuclear recombination activating gene 2, performed cranial measurements and searched for centric fusions in individuals collected in distinct localities. The results, clearly demonstrate that D. kempi, on the Coastal Plain, divided into two groups, one occupying a small portion to the north of this region and the other spreading widely to the south. In this process, the phenomena of marine transgression and regressions which moulded its habitat, together with the occurrence of successive chromosomal rearrangements, were certainly the fundamental factors in shaping D. kempi diversification.

Genetic diversity and relatedness within and between species of the genus Oligoryzomys (Rodentia; Sigmodontinae)

A RAPD analysis on six species of the rodent genus Oligoryzomys trapped in a wide area (ranging from 01 degrees N to 32 degrees S) of Brazilian territory was performed in order to determine the levels of genetic variability within and between its populations and species. One-hundred and ninety-three animals were collected in 13 different sites (corresponding to 17 samples) located at Pampas, Atlantic Rain Forest, Cerrado, and Amazon domains. Oligoryzomys sp., O. nigripes (8 populations), O. flavescens (4 populations), O. moojeni, O. stramineus, and O. fornesi were the taxa analyzed. Of the 20 primers tested, 4 generated a total of 75 polymorphic products simultaneously amplified in 151 specimens. Various diversity estimators analyzed showed considerable differences between species and populations, indicating a great genetic variation occurring in the Oligoryzomys taxa investigated. A cluster analysis was made using Nei's standard genetic distances, however, it did not correlate the genetic heterogeneity of the species and populations with the geographical areas.