Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Acurácia, precisão e robustez de indicadores internos para predição da digestibilidade aparente total de matéria seca em equinos

RESUMO Objetivou-se com este trabalho avaliar a acurácia, a precisão e a robustez de diferentes indicadores internos na predição da digestibilidade aparente total da matéria seca (MS) para equinos. Foram utilizadas cinco éguas em manutenção, sem raça definida, com peso médio de 406±76,9kg e idade aproximada de 3,5 anos, alojadas em baias individuais. O experimento foi disposto em quadrado latino 5x5 (cinco dietas e cinco animais). Foram coletadas amostras dos alimentos fornecidos e das fezes para determinação bromatológica dos indicadores, e, para determinação das frações indigestíveis, foi realizada incubação in vitro. Os indicadores utilizados foram fibra em detergente neutro indigestível (FDNi), fibra em detergente ácido indigestível (FDAi), celulose indigestível (CELi) e lignina em detergente ácido indigestível (LDAi). Os indicadores estudados tiveram médias de taxa de recuperação (TR) muito próximas a 100%. Em razão de uma menor taxa de recuperação, os indicadores FDNi e LDAi apresentaram vieses negativos e diferentes de zero (P0,05). A FDAi parece ser o indicador mais indicado para se estabelecerem valores de referências para digestibilidade. Com base nos resultados, é possível sugerir que a CELi é o indicador mais indicado para se compararem fatores entre o mesmo estudo

Effect of sorghum tannins in sheep fed with high-concentrate diets

The aim of this study was to evaluate the nutritional value of three sorghum cultivars with different concentrations of condensed tannins in sheep diets. Six adult sheep (LW=56kg) with rumen and duodenal fistulas were assigned to experimental groups using two 3x3 Latin Square designs. The diets were formulated using three sorghum cultivars: LTC (low-tannin cultivar), MTC (medium-tannin cultivar) and HTC (high-tannin cultivar). Microbial nitrogen (MN) concentration in the duodenum was measured using a 15N trace technique. LTC, MTC and HTC diets presented values of 788, 722 and 747 (SE=20.6) g kg-1 for dry matter digestibility and 633, 535 and 530 (SE=35.8) g/kg for crude protein digestibility. The LTC diet was significantly different from the other diets (P0.05) between the diets. The presence of condensed tannins in the sorghum interfered with the sheep's nitrogen retention; however, the microbial protein supply to the duodenum of the animals was not inhibited