Evaluation of the recovery potential of modified areas in Permanent Protection Areas of watercourses in the municipality of Rio Branco, Acre

In the last decades, the state of Acre has been showing increasing deforestation, concentrated mainly on the outskirts of its capital, Rio Branco. The present study was aimed at assessing the resilience level of water courses in Permanent Protection Areas (PPA) located in the city of Rio Branco. Were used orbital images from the Landsat 5 TM sensor for the mapping of soil utilization in the year of 2009. Was carried out the superposition of this map with the soil type map, as well as with the distance from seed sources, resulting in a final map of resilience level. Although protected by law, Rio Branco has about 17% of their PPAs watercourses altered. From the aspects evaluated in this study to determine the resilience, the soil type was the most limiting factor, while the distance of the sources of seeds was the most potentiating. The methodology allowed us to estimate the percentage of altered areas in the PPAs that are more resilient, thus allowing the implementation of the more appropriate and less expensive recovery programs for each area

ESTOQUE DE CARBONO EM ÁREAS DE RESTAURAÇÃO FLORESTAL DA MATA ATLÂNTICA

Ecossistemas florestais são importantes no processo de estocagem de carbono da atmosfera. Áreas de reflorestamentos podem contribuir de maneira substancial nesse processo e diminuir a pressão extrativista sobre florestas nativas. Este trabalho objetivou avaliar a biomassa acima do solo viva (por meio do método não-destrutivo – equações alométricas) e morta (serapilheira) e o estoque de carbono nesses compartimentos em áreas de reflorestamento com diferentes idades (3, 5 e 7 anos) e em área de Floresta Ombrófila Densa (testemunha), localizadas no município de Cachoeiras de Macacu (RJ). Foram alocadas 30 parcelas (10 x 10 m cada) na área testemunha e 20 parcelas (20 x 30 m cada) nas áreas de reflorestamento. Os indivíduos arbóreos foram identificados, e a altura total, circunferência e diâmetro à altura do peito foram medidos. A serapilheira foi coletada com gabarito quadrado (1 x 1 m) em cinco repetições em cada área. Os valores de biomassa acima do solo e carbono estocado aumentaram à medida que a idade dos plantios de restauração florestal avançou. Os modelos alométricos utilizados foram adequados no estudo. Contudo, é necessário testar a confiabilidade dos dados com a utilização do método destrutivo nas áreas reflorestadas

Digital soilscape mapping of tropical hillslope areas by neural networks

Geomorphometric variables are applied in digital soil mapping because of their strong correlation with the disposition and distribution of pedological components of the landscapes. In this research, the relationship between environmental components of tropical hillslope areas in the Rio de Janeiro State, Brazil, artificial neural networks (ANN), and maximum likelihood algorithm (MaxLike) were evaluated with the aid of geoprocessing techniques. ANN and MaxLike were applied to soilscape mapping and the results were compared to the original map. The ANN architectures with seven and five neurons in the hidden layer produced the best classifications when using samples obtained systematically. When random samples were applied, the best neural net architectures were within 22 and 16 neurons in the hidden layer. In conclusion, the ANN can contribute to soilscape surveys, making map delineation faster and less expensive. The digital elevation model (DEM) and its derived attributes can contribute to the understanding of the soil-landscape relationship of tropical hillslope areas; the use of artificial neural networks and MaxLike is feasible for digital soilscape mapping. The systematic sampling method provided a global accuracy of 70 % and 65.9 % for the ANN and the MaxLike, respectively. When the random sampling method was applied, the ANN had a global accuracy of 69.6 %, and the MaxLike had an accuracy of 62.1 %, considering the total study area in relation to the reference map

A origem da salinidade no Continente Antártico The origin of salinity in the Antarctic Continent

A Antártica é o mais perfeito laboratório natural do planeta para estudos de mudanças ambientais. Partindo dessa premissa, este estudo teve como objetivo realizar uma revisão sobre a origem dos sais presentes no continente antártico, sendo pormenorizado as principais formas e fontes salinas que ocorrem. Na literatura, este tema é de grande discussão, sendo relatado que a origem dos sais pode ser devido à precipitação atmosférica, intemperismo de rochas, origem marinha (spray salino), sulfatos biologicamente produzidos ou atividade hidrotermal. De maneira geral, a presente revisão permitiu inferir diversas origens dos sais solúveis em água nos solos da Antártica. Perto da costa, influências marinhas são dominantes, encobrindo quaisquer contribuições do intemperismo das rochas. Mas para o interior, a influência do intemperismo é mais evidente, ao passo que a influência de circulação atmosférica superior torna-se importante também. Ressalta-se também, a importância da contribuição continental no aporte de sais nos períodos glaciais.<br>The Antarctica is the most perfect natural laboratory to study the planet from environmental changes. From this premise, this study was to conduct a review on the origin of salts in the Antarctic, and detailed the main forms and sources occurring salt. In literature, this topic is of great discussion, and reported that the origin of salts may be due to precipitation, rock weathering, marine (salt spray), biologically produced sulfates or hydrothermal activity. Overall, this review allows us to infer various sources of water-soluble salts in soils of Antarctica. Near the coast, marine influences are dominant, covering up any contributions from weathering of rocks. But for the interior, the influence of weathering is more evident, while the influence of atmospheric circulation becomes more important as well. We also emphasize the importance of the contribution in the continental input of salts in glacial periods

Digital Soil Mapping Using Machine Learning Algorithms in a Tropical Mountainous Area

ABSTRACT: Increasingly, applications of machine learning techniques for digital soil mapping (DSM) are being used for different soil mapping purposes. Considering the variety of models available, it is important to know their performance in relation to soil data and environmental variables involved in soil mapping. This paper investigated the performance of eight machine learning algorithms for soil mapping in a tropical mountainous area of an official rural settlement in the Zona da Mata region in Brazil. Morphometric maps generated from a digital elevation model, together with Landsat-8 satellite imagery, and climatic maps, were among the set of covariates to be selected by the Recursive Feature Elimination algorithm to predict soil types using machine learning algorithms. Mapping performance was assessed using the confusion matrix, and the Z-test among the Kappa indexes of the matrices. In a conventional soil survey, the soils described and classified in the Brazilian System of Soil Classification [Argissolos Vermelho-Amarelos Distróficos – PVAd (Acrisols), Cambissolos Háplicos Tb Distróficos - CXbd (Cambisols), Gleissolos Háplicos Háplicos Tb Distróficos - GXbd (Gleysols), Latossolos Amarelos Distróficos - LAd (Xanthic Ferralsos), Latossolos Vermelho-Amarelos Distróficos - LVAd (Rhodic Ferralsols), and Neossolos Litólicos Distróficos - RLd (Neossols)] were grouped into composite mapping units (MU) using the conventional method. The eight algorithms showed similar performance without statistical difference (Kappa 0.42-0.48). The mapping of soils with varying slopes (LAd, LVAd, CXbd) showed lower accuracy, whereas soils on hydromorphic lowlands (GXbd) were classified more accurately. In map algebra, the result was rather satisfactory, with 63-67 % agreement between the conventional soil map and maps produced by machine learning. The areas with the largest disagreement in the DSM occurred in the LAd unit due to subtle color variation in the Latossolos mantle without a clear relation to any environmental variable, highlighting difficulties in DSM regarding hill slope landforms. Model performance was satisfactory, and good agreement with the conventional soil map demonstrates the importance of the DSM as a potential complementary tool for assisting soil mapping in mountainous areas in Brazil for the purpose of land use planning

PAISAGENS POLARES NÃO GLACIAIS (PROGLACIAL, PARAGLACIAL E PERIGLACIAL): REVISÃO DE CONCEITOS E CONSTRIBUIÇÕES DA PESQUISA PEDOGEOMORFOLÓGICA BRASILEIRA

O trabalho teve como objetivo discutir com base na literatura a origem e evolução dos conceitos proglacial, paraglacial e periglacial, elucidando as formas e processos atuantes e as questões e críticas inerentes a cada um deles. Ao longo dos anos os três termos foram empregados de forma redundante e sobreposta, mesmo refletindo conjunturas ambientais distintas, com critérios diagnósticos diferentes. Ademais, mesmo com a participação crescente de pesquisadores brasileiros em trabalhos na Antártica, as discussões epistemológicas acerca desses ambientes ainda constituem lacuna nas publicações nacionais. A paisagem proglacial corresponde à área pioneira em receber os produtos da glaciação e este se revela um ambiente prioritariamente deposicional. É um ambiente complexo totalmente ajustado aos processos fluviais, lacustres e marinhos que ocorrem imediatamente adjacente ao glaciar e consequentemente o domínio proglacial acompanha a movimentação da margem do gelo. A paisagem paraglacial não é definida nem por processos nem pela localização, mas sim pela trajetória de reajustes da paisagem, adotando o critério tempo. Dessa forma, a paisagem paraglacial está em processo de transição, recuperando-se dos distúrbios da glaciação. Por fim, a paisagem periglacial é aquela com atuação de ciclos de congelamento e descongelamento (frost action) e congelamento sazonal do terreno, podendo possuir ou não permafrost.</p

Environmental Correlation and Spatial Autocorrelation of Soil Properties in Keller Peninsula, Maritime Antarctica

<div><p>ABSTRACT: The pattern of variation in soil and landform properties in relation to environmental covariates are closely related to soil type distribution. The aim of this study was to apply digital soil mapping techniques to analysis of the pattern of soil property variation in relation to environmental covariates under periglacial conditions at Keller Peninsula, Maritime Antarctica. We considered the hypothesis that covariates normally used for environmental correlation elsewhere can be adequately employed in periglacial areas in Maritime Antarctica. For that purpose, 138 soil samples from 47 soil sites were collected for analysis of soil chemical and physical properties. We tested the correlation between soil properties (clay, potassium, sand, organic carbon, and pH) and environmental covariates. The environmental covariates selected were correlated with soil properties according to the terrain attributes of the digital elevation model (DEM). The models evaluated were linear regression, ordinary kriging, and regression kriging. The best performance was obtained using normalized height as a covariate, with an R2 of 0.59 for sand. In contrast, the lowest R2 of 0.15 was obtained for organic carbon, also using the regression kriging method. Overall, results indicate that, despite the predominant periglacial conditions, the environmental covariates normally used for digital terrain mapping of soil properties worldwide can be successfully employed for understanding the main variations in soil properties and soil-forming factors in this region.</p></div

Active layer and permafrost thermal regimes in the ice-free areas of Antarctica

DATA AVAILABILITY : Data will be made available on request.Please read abstract in the article.Czech Scientific Foundation, Masaryk University internal project and Czech Antarctic Research Programme funded by MEYS of Czech Republic; project NUNANTAR (Fundação para a Ciência e Tecnologia of Portugal) and the research groups ANTALP (Antarctic, Arctic, Alpine Environments) funded by the Agència de Gestió d'Ajuts Universitaris i de Recerca of the Government of Catalonia; PNRA (Programma Nazionale di Ricerca in Antartica) for the logistical and financial support in Continental Antarctica, Antarctic Peninsula and in Signy Island.https://www.elsevier.com/locate/earscirev2024-06-07hj2023Geography, Geoinformatics and Meteorolog