Sapientia
Repositório Científico da UAlg
Entradas recentes
O feitiço do ouro
Publication . Carvalho, Ana Alexandra Mendonça Seabra da Silva Andrade de; Carvalho, João Carlos Firmino Andrade de
O segundo pecado capital da Antologia organizada por Afonso Praça é a Avareza, que ficou a cargo do próprio em “Cenas da Vida Real” (Praça, 2005: 51-65). A avareza parece ser o pecado mortal que menos suscita a nossa indulgência, odiado quase unanimemente. Com maior facilidade, poderíamos admitir vícios como a soberba, a gula, a ira, a luxúria, a preguiça, até mesmo a inveja, mas nunca a avareza. Desprezamos personagens como o Tio Patinhas dos livros de quadradinhos da nossa infância, o Mr. Scrooge da Canção de Natal 2 , o Euclião de Plauto3 , o Harpagon de Molière4 e muitos outros completamente cativados pela febre do ouro. Do latim avaritia, este traço de caráter interessou muitos filósofos e artistas desde a Antiguidade, tendo sido alvo de duras críticas.
Quatro elogios da preguiça
Publication . Carvalho, Ana Alexandra Mendonça Seabra da Silva Andrade de
O sétimo pecado capital da Antologia organizada por Afonso Praça é a Preguiça, que ficou a cargo de Fernando Dacosta em “Reformular a Utopia” (Dacosta, 2005: 153). Ao longo de 15 páginas, o autor desenvolve um texto de natureza ensaística refletindo sobre a Preguiça numa perspetiva positiva, impulsionadora da criatividade e da utopia transformadora. Diz ele: “o português encontra na imobilidade pulsões de criação. Por isso, cultivou as navegações, a poesia, o saudosismo, o messianismo, o fatalismo; por isso, se lava em lágrimas, deleita em desgraças, adia esperas” (Dacosta, 2005: 164). “Fábula de fim de milénio”, segundo o autor, nela se cruzam as simbologias da formiga (produção), do coelho (reprodução) e da lagartixa (inação), de modo a “fazerem hibernar, de vez, a cigarra” (Dacosta, 2005: 167, itálicos nossos).
UAV-based soil erosion assessment in mediterranean agricultural orchards
Publication . Pagter, Tijs de; Canedo, João Nuno Gomes Vicente; Pijl, Anton; Guerreiro David Coelho, Luísa Isabel; Nunes, João Pedro; Prats, Sergio
Unmanned Aerial Vehicle (UAV) imagery has become an important tool for erosion monitoring, but little is known about its application in Mediterranean agricultural systems such as vineyards and olive groves. In this study, drone flights were conducted in vineyards and olive groves where mulch and biochar treatments had been applied. Digital terrain models (DTMs) and orthomosaics were constructed using a photogrammetry workflow, and model error was determined via global positioning system (GPS) transects. Erosion was assessed using Digital elevation models of Difference (DoD) and compared with fieldbased erosion plot measurements. Explanatory variables for erosion (soil roughness, slope length, steepness, vegetation cover) were derived from DTMs and orthomosaics and were evaluated in a multiple linear regression model. Although direct measurement of erosion from the DoDs was difficult, this was primarily influenced by the unexpectedly low erosion rates during the study period, and the high root mean square error (RMSE) of the DTMs. Significant differences in DTM-derived variables were found between study areas, and especially between areas with organic and integrated management, even though treatments showed similar patterns. The multiple linear regression model demonstrated strong explanatory power, accounting for a large part of the variation in measured erosion using the UAV-derived variables (R 2 = 0.81). Slope and slope length were the most important predictors of erosion together with the interaction between these two variables. The results suggest that soil erosion in the study areas was mostly determined by topographic and management factors, rather than the applied treatments. This study highlights the value of UAV imagery in advancing the understanding of erosion processes in Mediterranean agricultural systems, while also identifying the challenge of accurately measuring erosion from DoDs under conditions of low erosion rates.
Impacts of climate change on the hydrology of a highly disturbed tropical river basin
Publication . Alvarenga, Claudiana Mesquita de; Alvarenga, Lívia Alves; Melo, Pâmela Aparecida; Tomasella, Javier; Pinto, Pâmela Rafanele França; Mello, Carlos Rogério de; Isidoro, Jorge
Climate change significantly affects hydrological responses, yet studies addressing future water availability in the Paraopeba River Basin (PRB), an important tributary of the São Francisco River Basin in Brazil, remain limited, particularly under CMIP6 scenarios and using distributed hydrological modeling approaches. In this context, this study evaluated the hydrological responses of the PRB, under climate change using the MHD-INPE. Future projections were based on an ensemble of seven climate models from the NEX-GDDP-CMIP6 collection, considering a baseline period (1992–2014), three future periods 17(2040–2060, 2061–2080 and 2081–2100) and two socioeconomic scenarios (SSP245 and SSP585). The model satisfactorily reproduced observed streamflow during the baseline period. Under the SSP585 scenario, the projections indicate stronger alterations in water availability, with a potential intensification of flood and drought events, as reflected by reductions in minimum streamflows (Q90) and increases in maximum streamflows (Q10), particularly in sub-basins 4 and 5, where Q90 reductions approach 30% and Q10 increases reach 11.7%. Additionally, a decrease in Q7,10 values was observed, which enabled the analysis of the Conflict Index (Icg), indicating that water withdrawals currently granted may exceed the limits established by existing legislation in future scenarios (Igc > 1).
Adapting mediterranean agroforestry to global change: trade-offs and lessons from the montado
Publication . Fatahi, Nour-Elhouda; Pinto-Correia, Teresa; Ferreira da Silva da Costa Freitas, Maria de Belém; Marques, João Tiago; Belhouchette, Hatem
The Montado, a traditional Mediterranean agro-silvopastoral system, has historically sustained ecological and economic functions through the integration of trees, livestock, and crops. Today, its multifunctionality is increasingly threatened by climate variability, market volatility, and evolving policy frameworks. While previous research has examined Montado dynamics at landscape or plot scales, less attention has been paid to sustainability trajectories at the farm level, where management decisions are made. This study bridges that gap by assessing the sustainability dynamics of farms through a participatory, typology based, scenario approach grounded in a regional typology. We characterized three representative farm archetypes (forestry-focused, mixed agro-silvopastoral, and livestock-focused) and evaluated their trajectories under plausible future scenarios driven by climate, market, and policy pressures. Scenario outcomes were assessed using expert-based scoring (five-point scale), revealing score differences of up to two points across sustainability dimensions between farm archetypes and scenarios. Findings reveal marked trade-offs: Tree-focused farms maintain high environmental value but remain vulnerable to market and labor constraints, while livestock-specialized farms achieve higher economic output at the expense of ecological integrity. Mixed systems demonstrate greater resilience through diversification but face significant labor intensity challenges. We conclude that current “one-size-fits-all” policies generate contradictory incentives. Therefore, adaptive governance frameworks (e.g., results-based payment schemes) are essential to realign farm economics with ecological stewardship. Beyond the Montado, the approach provides insights relevant to other Mediterranean agroforestry systems facing similar sustainability challenges.