FCT1-Teses
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Percorrer FCT1-Teses por Objetivos de Desenvolvimento Sustentável (ODS) "ODS 15 — Vida Terrestre"
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- Ecohydrological assessment of a complex river-floodplain system for the enhancement of its multidimensional potentialPublication . Guzmán, Damaris Rios; Chicharo, Luis; Jarosiewicz, PawełRiver floodplain systems are critical for sustaining biodiversity and providing a wide range of ecosystem services. However, climate change and anthropogenic activities increasingly disrupt the hydrological and ecological connectivity of these systems, red ucing their resilience to external pressures. The degradation of floodplains undermines key ecosystem services, including the support of terrestrial and aquatic biodiversity, the regulation of hydrological extremes such as floods and droughts, and the sequ estration of carbon. Given the global challenges of water scarcity and associated ecological consequences, there is an urgent need for innovative management strategies to enhance the mult idimensional roles of floodplains in water resource management, biodiversity conservation, and climate change adaptation. Therefore, this thesis focused on the study of the river floodplain system that was selected as the demonstration site for the ecohydrological project LIFE Pilica (LIFE19 IPE/PL/000005) in Central Poland. The study addresse d the hydrological connectivity within the river floodplain system during spring and early summer, assessing its effects on water quality. A particular focus was placed on phosphorus dynamics between the water and sediment compartments, aiming to propose management strategies that mitigat e excessive phosphorus release for a sustainable water retention in the floodplain area. Three primary hydrological connection s were identified between the studied floodplain, Pilica river and an upstream wetland . The connectivity decreased significantly throughout the study (from 0.185 m 3 s 1 in March to 0.002 m 3 s 1 in May )), with the first connection turning into a drainage source in April due to Pilica’s water level decrease . By May, the second source dried up, and the third was projected to cease at a river discharge below 12 m³s⁻¹ (R² = 0.94). Principal Component Analysis (PCA) revealed a greater difference between water quality from the o xbow l ake with the river ’s inflow (35.4%) than with the wetland’s outflow ( 15.5%). This shift underscores an increased risk of eutrophication in both water bodies, driven by prolonged residence times, nutrient accumulation, and the lack of water exchange from the river. Sediment analysis revealed significant differences in water content and organic matter between samples ( p < 0.05 at the studied floodplain part . Most sediments were rich in organic phosphorus and bound to Fe, Al, and Mn. Sorption tests showed greater phosphorus adsorption in air dried sediments and a high zero equilibrium phosphorus concentration (EPC₀), indicating a tendency to release phosphoru s when exposed to river water , thus highlighting the need of proper management prior increasing hydrological connectivity . In conclusion, the implementation of a water retention basin in the area will tackle the greatest threat to the studied river floodplain system: the progressive loss of hydrological connectivity. Furthermore, the potential risk of phosphorus release was ev aluated to refine the management strategy , ensuring it effectively mitigates nutrient loading and supports long term ecosystem health.
- Point and diffuse sources of pollution in the Pilica catchment: An ecohydrological assessment as the first step for water resources managementPublication . Rios, Marina Victoria; Chícharo, Luís; Jarosiewicz, PawełWe face a growing threat of not achieving the Sustainable Development Goals in 2030, including water security, which is crucial for ecosystems, human health and economic development. Growing challenges like pollution, over-extraction, climate change and poor management practices hinder our progress. Consequently, there is a growing need for new methods and approaches to demonstrate sustainable water management in practice. This is why, the Pilica River Catchment in Central Poland was recognized as one of the UNESCO Intergovernmental Hydrological Programme Ecohydrology Demonstration Sites. This catchment faces multiple ecological challenges due to water pollution coming from both, point and diffuse sources. Following the first principle of ecohydrology, this study analyses the temporal and spatial dynamics of nutrient concentrations and loads as a first step for effective water resources management. By combining multiple statistical analysis, the study identifies the primary nutrient sources and the critical seasons for the dominance of different pollutants. Findings revealed that sub-catchments dominated by agricultural land exhibited higher nutrients, evidencing the impact of agriculture on water quality. Mainly, the impact of point sources for total phosphorus was observed during low flow seasons when the discharge share was higher and for total nitrogen during cold seasons, when the self-purification capacity of the streams was lower. These insights provide valuable contributions to the development of integrated river basin management plans, to boost the catchment’s sustainability potential, expressed by water, biodiversity, ecosystem services and resilience and implement further steps of ecohydrology to develop systemic solutions in the catchment scale.
- Temporal variations in phenological patterns of olive ridley turtles (lepidochelys olivacea) in manono-bentiaba, AngolaPublication . Mangueira, Edson de Jesus Delgado; Baptista, Vânia; Gouvêa, Lidiane PiresSea turtles are migratory reptiles with a complex life cycle. Of the seven recorded species of sea turtles, three use Angolan waters: the leatherback, the green turtle and the olive ridley, which are confirmed as species that nest in Angola. Sea turtles play an important role in maintaining the balance of marine ecosystems, as they are marine and terrestrial bioindicators, participate in food chains and energy transfer, and have sociocultural and economic value. The decline in the sea turtle population is a cause for concern for their conservation, since all species are on the Angolan red list of species. Threats from climatic factors (temperature, precipitation, humidity, erosion, flooding, disease) and anthropogenic pressures (hunting and egg collection, coastal occupation and development, habitat degradation and high-powered vessels in sensitive areas) can influence the decline of these populations. In this context, the present study aims to examine the phenological patterns of Lepidochelys olivacea in Angola, with a specific focus on the Bentiaba region from 2018 to 2022. The surveys were conducted between September and March from 2018 to 2019 and from 2021 to 2022. The results showed a total of 264 nests during this period with declines in nesting and consequently in turtle hatching from 2018 to 2022, with 133 nests in the 2018-2019 season and 131 nests in the 2021-2022 season. October and December of 2018, February and March of 2019, presented with the highest egg density, while February and March of 2022, presented with the lowest egg density. November and December of 2021, and February and March of 2022, were the months with the highest mortality rate. This study includes monitoring nesting sites where eggs are laid and inspected, providing a baseline for conservation to identify the main stages where declines in nests, eggs and neonates occur.