Long-term meteorological analyzes suggest an increase in air temperature and a decrease in rainfall over the Amazon biome. The effect of these climate changes on the forest remains unresolved, because field observations on functional traits are sparse in time and space, and the results from remote sensing analyses are divergent. Then, we analyzed the drought response in a ‘terra firme’ forest fragment in the southwestern Amazonia, during an extreme drought event influenced by ENSO episode (2015/2017), focusing on stem growth, litter production, functional traits and forest canopy dynamics. We use the Moderate Resolution Imaging Spectroradiometer (MODIS), corrected by Multi-Angle Implementation of Atmospheric Correction (MAIAC) to generate the enhanced vegetation index (EVI) and green chromatic coordinate (Gcc) vegetation indices. We monitor stem growth and measure the functional traits of trees in situ, such as the potential at which the plant loses 50% of hydraulic conductivity (P50), turgor loss point (πTLP), hydraulic safety margin (HSM) and isohydricity. Our results suggest that: (a) during the dry season, there is a smooth reduction in EVI values (browning) and an increase in the wet season (greening); (b) in the dry season, leaf flush occurs, when the water table still has a quota at the limit of the root zone; (c) the forest showed moderate resistance to drought, with water as the primary limiting factor, and the thickest trees were the most resistant; and (d) a decline in stem growth post-El-Niño 2015/2016 was observed, suggesting that the persistence of negative rainfall anomalies may be as critical to the forest as the drought episode itself.
The present work aimed to investigate the potential sources of water for plants in an area of evergreen forest located in western Amazonia (Rebio Jaru). We used a natural abundance of water isotopes—δ2H and δ18O—to trace the main source of water to plants at the beginning of the dry period (May 2016) and at the end of the dry period/transition to the wet period (October 2016) following a severe El Niño drought (ENSO 2015/16). Soil samples were collected in a soil profile up to 4 m depth. Plant samples from 18 trees (14 species) were collected in May and in October 2016. Rainwater and river water samples were collected between September 2015 and February 2017. We found that, at the end of the dry period/transition to the wet period (i.e., October 2016), the average plant xylem signal was more enriched (δ2H: −20.0 ± 8.1‰; δ18O: −1.13 ± 1.88‰) than in May 2016 (δ2H: −36.7 ± 5.6‰; δ18O: −3.50 ± 1.30‰), the onset of the dry period. The averaged isotopic soil signal in May 2016 (δ2H: −35.4 ± 5.90‰; δ18O: −5.19 ± 0.70‰) is slightly more depleted than in October (δ2H: −27.6 ± 13.8‰; δ18O: −4.35 ± 1.73‰) and, in general, more depleted than the xylem signal. In the dual isotope space, the xylem signal at the beginning of the dry period follows the rainfall signal of the wet period, while the xylem signal at the end of the dry period/transition to the wet period follows the signal of the dry season rainfall, suggesting that plants mostly transpire recent rainwater. Contrary to what was expected, we did not find evidence in the xylem signal of the water stored in the soil pores, which suggests that to meet to the water demands of the dry period, plants do not use the water from past periods stored in the soil layers.
Several colonisation projects were implemented in the Brazilian Legal Amazon in the 1970s and 1980s. Among these colonisation projects, the most prominent were those with the “fishbone” and “topographic” models. Within this scope, the settlements known as Anari and Machadinho stand out because they are contiguous areas with different models and structures of occupation and colonisation. The main objective of this work was to evaluate the dynamics of Land-Use and Land-Cover (LULC) in two different colonisation models, implanted in the State of Rondônia in the 1980s. The fishbone and topographic or Disorganised Multidirectional models were implemented in the Anari and Machadinho settlements, respectively. A 36-year time series of Landsat images (1984–2020) was used to evaluate the rates and trends in the LULC process in the different colonisation models. In the analysed models, a rapid loss of primary and secondary forests (anthropized areas) was observed, mainly due to the dynamics of its use, established by the Agriculture/Pasture relation with a heavy dependence on road construction. Understanding these two forms of occupation can help the future programs and guidelines of the Brazilian Legal Amazon and any tropical rainforest across the globe.
A região Amazônica devido a sua extensão, é composta por um intrincado mosaico de ambientes, definido não só pela heterogeneidade dos seus ecossistemas, como também pelo processo de ocupação e desenvolvimento. Com base em tal aspecto, o crescimento das populações e a expansão das áreas urbanas em todo o mundo têm elevado o uso e definido transformações na cobertura do solo. Assim objetivou-se com este trabalho realizar o mapeamento de uso e cobertura do solo nos arredores de Rondônia. O estudo foi realizado nos municípios de Corumbiara, Chupinguaia e Cerejeiras, estes localizados no sul do estado de Rondônia, onde as imagens utilizadas para as análises foram adquiridas na plataforma da Divisão Geral de Imagens (DGI) do Instituto Nacional de Pesquisas Espaciais (INPE), imagens de 1990 do sensor TM (Thematic Mapper) a bordo do satélite Landsat-5, e de 2017 do sensor OLI (Operational land imager) a bordo do satélite Landsat-8, caracterizados por uma resolução espacial de 30 metros e resolução temporal de 16 dias. Os resultados evidenciaram uma área com significativo desmatamento, onde aproximadamente 2/4 do território total dos municípios teve sua vegetação original retirada e, desta forma, evidencia uma irregularidade quando comparado com a legislação ambiental (Lei nº 12.651/2012).
Trata-se de uma pesquisa estruturada na análise do discurso, que relata o processo de consolidação, transformação e decadência de uma cultura nomeada “samba de couro”, na região central do Estado de Rondônia. Alicerçada inicialmente em uma tradição religiosa, em comemoração ao nascimento de Cristo, o “Samba de Couro” chegou a Rondônia com o processo migratório para colonização realizado pelo INCRA (Instituto Nacional de Colonização e Reforma Agrária). Atualmente, apesar de já ter tido cunho religioso com relações de fé ao divino, passou a ser uma representação de diversão que vem declinando pela não adesão da descendência à tradição. Abstract CULTURAL HYBRIDIZATION: THE CASE OF “SAMBA DE COURO” IN THE CENTRAL REGION FROM RONDONIA STATE, BRAZIL This paper is a research structured in discourse analysis, which reports the process of consolidation, transformation and decay of a culture named “Samba de Couro” (“samba of leather”) in the central region of Rondônia State. Initially founded in a religious tradition to celebrate the birth of Christ, the “samba of leather” arrived Rondônia with the migration process for settlement performed by INCRA (National Institute for Colonization and Agrarian Reform). Nowadays, despite its former religious character in relation with the faith in Holy Ghost, it became a representation of diversion that has been declining for the descendents tradition non-attach.
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