The Brazilian savanna, South America’s second-largest biome, is vital to Brazil’s economy but has suffered from environmental degradation due to unregulated agricultural and urban expansion. This study assesses climate change in the biome from 1961 to 2021 using the Köppen climate classification, drought indices, historical trend analyses, and the climatological water balance. Fourteen municipalities across the biome were analyzed. According to the Köppen classification, most municipalities were identified as Aw (tropical with dry winters) and Am (tropical monsoon), with Dourados, MS, and Sapezal, MT, alternating between Am and Aw. The standardized precipitation index (SPI) revealed changes in rainfall distribution. The Mann–Kendall test detected rising air temperatures in 13 of the 14 municipalities, with Sen’s slope ranging from 0.0156 to 0.0605 °C per year. Rainfall decreased in seven municipalities, with decreases from −4.54 to −12.77 mm per year. The climatological water balance supported the observed decrease in precipitation. The results indicated a clear warming trend and declining rainfall in most of the Brazilian savanna, highlighting potential challenges for water availability in the face of ongoing climate change.

Aim The aim of this study was to evaluate how phytoplankton community diversity, dominance, and rarity are influenced by different local environmental conditions in urban lakes. We expect that richness will be negatively influenced in lakes with higher nutrient concentrations and high turbidity, while abundance will be positively influenced. Thus, lakes with these conditions will have greater dominance of a few species and lower rarity, and the opposite in lakes with lower nutrient concentrations and less turbidity. Methods Phytoplankton and abiotic variables samples were collected in fourteen lakes distributed in the municipality of Goiânia, Goiás, Brazil, during a rainy period. Results It was possible to identify an environmental heterogeneity among the lakes. We identified a separation of the lakes according to phytoplankton richness and density, especially due to the contribution of green algae, desmids, and cyanobacteria. Most lakes showed high diversity and evenness values, with a predominance of rare taxa and few dominant species. The main variables associated with phytoplankton were water temperature, dissolved oxygen, turbidity, and nutrient concentrations. Conclusions Therefore, the study of species diversity, dominance, and rarity based on phytoplankton richness and abundance and their relationship with different local environmental conditions can be an important model for assessing water quality in urban lakes.

A Espada de São Jorge e uma planta amplamente cultivada como ornamental pertencente a família Asparagaceae. As espécies dessa família frequentemente apresentam rizomas como órgãos de armazenamento e os principais carboidratos não estruturais armazenados são os frutanos. Estes compostos são polímeros de frutose derivados de sacarose. Devido aos seus inúmeros benefícios, são de grande interesse a indústria alimentícia e farmacêutica. Objetivou-se com esse trabalho quantificar os teores de carboidratos não estruturais e verificar a presença de frutanos em rizomas e raízes de Espada de São Jorge. Para isso, foram coletados na estação seca os órgãos subterrâneos de plantas cultivadas em um canteiro, mas que não são irrigadas. Foram avaliados o conteúdo de agua e o teor de carboidratos solúveis em ambos os órgãos. Os rizomas da espécie apresentaram maior conteúdo de agua e maior teor de carboidratos solúveis que as raízes. Por analises qualitativas dos carboidratos solúveis por cromatografia de troca aniônica de alto desempenho, verificou-se a presença de frutanos em ambos os órgãos, com perfil semelhante ao observado em extratos de bulbos de cebola. Concluímos que os órgãos subterrâneos de Espada de São Jorge armazenam frutanos com estruturas diversificadas que correspondem a neosserie da inulina e que, especialmente os rizomas da Espada de São Jorge são fonte promissora para a obtenção de frutanos.