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- Modelling the role of ground-true riparian vegetation for providing regulating services in a Mediterranean watershedPublication . Aparício, Bruno A.; Nunes, João Pedro; Bernard-Jannin, Léonard; Dias, Luís Filipe; Fonseca, André; Ferreira, TeresaIntensive agricultural and industrial activities are often considered major sources of water contamination. Currently, riparian vegetation (RV) is increasingly being promoted as a solution to balance the potentially adverse effects that agriculture may have on water quality. Nonetheless, existing RV is often overlook in recent modelling efforts, failing to capture the current amount of ecosystem services provide. Here, we used the Soil and Water Assessment Tool ecohydrological model to simulate the influence of ground-true RV on i) nutrient (nitrate and total phosphorus) and sediment exports from agricultural areas and ii) its effect for in-stream concentrations. These results are further compared against a set of hypothetical scenarios of different RV widths and different land-uses. Our results point to a great relevance of existing RV in controlling in-stream concentration of sediments and nutrients where pressure from agriculture is highest, preventing them to surpass limits set in the EU Water Framework Directive. On the other hand, in areas with industry discharges, the role of RV is limited and model results suggest that restoring RV would have limited impacts. We illustrate how existing RV may already provide strong but not acknowledged water quality regulation services, how these services can differ substantially between nearby streams, and that effective strategies to improve water quality using RV must acknowledge existing patterns of vegetation, land use and contamination sources.
- Assessing the climate change adaptability of sustainable land management practices regarding water availability and quality: A case study in the Sorraia catchment, PortugalPublication . van der Laan, Esther; Nunes, João Pedro; Dias, Luís Filipe; Carvalho, S.C.P.; Mendonça dos Santos, FrancianeIn Mediterranean catchments, such as the Sorraia catchment in Portugal, it is expected that climate change will increase drought stress and the deterioration of water quality in reservoirs. Sustainable land management (SLM) practices are seen as an adaption measure for those problems, but the effectiveness on improving climate change impacted water availability and quality on catchment scale is still poorly understood. Therefore, this study aims to evaluate the effectiveness of SLM practices in adapting the impacts of climate change on water availability and quality of the Montargil and Maranhão reservoirs in the Sorraia catchment. A well-calibrated Soil Water Assessment Tool model is used to simulate four scenarios (2041–2071 and 2071–2100; representative climate pathways 4.5 and 8.5), to investigate the effects of climate change on total phosphorus load (TP) in streams, reservoir volume, irrigation use and water exploitation index (WEI). Results showed that WEI will not exceed any water stress level while reservoir water quality will worsen. In particular since the TP load in streams flowing into the reservoirs increases and the volume decreases, it is likely that the existing P limitation for eutrophication will be counteracted. Nevertheless, tested SLM practices were able to decrease the TP load in those streams and increase the reservoir volume under future climates. Overall, this study shows that the SLM practices are effective in adapting to the climate change effects regarding reservoir water quality, without worsening the water availability; thus, it is a promising tool that should be investigated further for application by e.g. local land-users and decision makers.
- Increased policy ambition is needed to avoid the effects of climate change and reach carbon removal targets in PortugalPublication . Pedersen, Jiesper Strandsbjerg Tristan; Dias, Luís Filipe; Kok, Kasper; van Vuuren, Detlef; Soares, Pedro M. M.; Santos, Filipe; Azevedo, João C.The Paris Agreement’s goal of limiting global warming hinges on forest carbon sequestration as a key in several national strategies. However, Portugal’s rising forest fire occurrences threaten its ability to meet ambitious 2030 and 2050 carbon sequestration targets. Considering fire and forest trends, this study aims to quantify whether Portugal can reach its carbon sequestration ambitions as stated in its 2030 and 2050 targets. We tested three national forest scenario extensions of the global Shared Socioeconomic Pathways (SSPs) and Shared Policy Assumptions (SPAs) based on a dynamic model, simulating forest area and carbon sequestration related to future fire risk and policies of fire management, forest management, restoration of burnt areas, and climate change adaptation. The model projects a rapidly decreasing forest area under existing Portuguese policies (PT-SSP3), a slow decline under moderate policy improvements (PT-SSP2), and an almost stable forest area under long-term sustainable policy developments (PT-SSP1). In PT-SSP3, carbon sequestration will be reduced to 60% by 2050 compared to 2015, while it declines to about 85% and 90% under PT-SSP2 and PT-SSP1, respectively. It is still plausible to reach Portugal’s 2030 sequestration obligations under the EU’s Paris Agreement target under all three scenarios, while the Portuguese GHG neutrality target is not reached in the presented scenarios. Our four introduced policy areas (increasing focus on fire and forest management, forest restoration, and climate change adaptation of forest stands) must be supplemented by other policy strategies, such as reforestation.
- Assessing the climate change adaptability of sustainable land management practices regarding water availability and quality: A case study in the Sorraia catchment, PortugalPublication . van der Laan, Esther; Nunes, João Pedro; Dias, Luís Filipe; Carvalho, Sílvia; Mendonça dos Santos, FrancianeIn Mediterranean catchments, such as the Sorraia catchment in Portugal, it is expected that climate change will increase drought stress and the deterioration of water quality in reservoirs. Sustainable land management (SLM) practices are seen as an adaption measure for those problems, but the effectiveness on improving climate change impacted water availability and quality on catchment scale is still poorly understood. Therefore, this study aims to evaluate the effectiveness of SLM practices in adapting the impacts of climate change on water availability and quality of the Montargil and Maranhão reservoirs in the Sorraia catchment. A well-calibrated Soil Water Assessment Tool model is used to simulate four scenarios (2041–2071 and 2071–2100; representative climate pathways 4.5 and 8.5), to investigate the effects of climate change on total phosphorus load (TP) in streams, reservoir volume, irrigation use and water exploitation index (WEI). Results showed that WEI will not exceed any water stress level while reservoir water quality will worsen. In particular since the TP load in streams flowing into the reservoirs increases and the volume decreases, it is likely that the existing P limitation for eutrophication will be counteracted. Nevertheless, tested SLM practices were able to decrease the TP load in those streams and increase the reservoir volume under future climates. Overall, this study shows that the SLM practices are effective in adapting to the climate change effects regarding reservoir water quality, without worsening the water availability; thus, it is a promising tool that should be investigated further for application by e.g. local land-users and decision makers.
- Impact of nature-based solutions on sustainable development goals in Mediterranean agroecosystems: A meta-analysisPublication . Rodrigues, Miguel; Dias, Luís Filipe; Nunes, João PedroMediterranean agroecosystems' vulnerability to hydroclimatic extremes threatens their resilience and sustainability. Nature-based Solutions present a sustainable strategy to address global challenges. This meta-analysis of 70 studies developed in Mediterranean climates identified solutions to improve soil health and water quality in agroecosystems by estimating their effects on soil organic matter, organic carbon, water, erosion, and Kjeldahl nitrogen, total nitrogen, nitrate, total phosphorus, phosphate, and suspended solids, respectively. Using meta-regression, we analysed how the interaction with biophysical conditions (e.g., soil texture and irrigation practices for soil health and macrophyte species and temperature for water quality) drives the effects of Nature-based Solutions. The results indicate that these solutions can improve soil health and water quality, supporting the achievement of land and water Sustainable Development Goals. Among all the options considered for rehabilitating land ecosystems, afforestation led to significant increases in soil organic carbon up to 137%. Of all tillage practices tested, eliminating soil disturbance combined with using cover crops and mulching revealed the potential to counteract agricultural land degradation, showing significant reductions in erosion as high as 98%. The individual application of organic inputs showed the potential to reverse ongoing agricultural soil degradation trends. Applying olive mill wastewater was associated with a significant increase of 249\% in soil organic matter. However, applying manure compost in no-tilled plots with herbaceous cover reduced the soil water content at field capacity by 46\%.Constructed wetlands have shown the most significant results in improving water quality by reducing pollutants and contributing to protecting and restoring aquatic ecosystems. Polycultural systems with horizontal subsurface flow reduced Kjeldahl nitrogen by 9%, nitrates and phosphorus by 3%, and total suspended solids by 10%. However, in continuous aerated systems, nitrate levels increased by 36%. The reduction in total nitrogen in subsurface vertical flow systems was 11%, while surface flow wetlands with two macrophyte species reduced total suspended solids by 6%. Implementing Nature-based Solutions in Mediterranean agroecosystems depended on biophysical conditions, highlighting the need for site-specific adaptation based on local conditions and objectives. In a global change scenario, mainstreaming these solutions as sustainable land and water management practices is vital for enhancing the resilience and sustainability of Mediterranean agroecosystems, providing ecosystem services beyond soil health and water quality, including climate change mitigation, biodiversity protection and human well-being.
- Evaluating Nature-based Solutions as urban resilience and climate adaptation tools: A meta-analysis of their benefits on heatwaves and floodsPublication . Ferrario, Francesco; Mourato, João Morais; Rodrigues, Miguel Silva; Dias, Luís FilipeExtreme weather events driven by climate change threaten the resilience of urban structures and urban dwellers. Nature-based Solutions (NbS) are an effective tool to reduce urban vulnerability to climate risks and, at the same time, develop more liveable urban areas. Despite the acknowledged positive impacts of individual observed NbS, numerous questions persist unanswered. While existing research supports NbS' positive influence on urban climate adaptation, the extent of their impact remains insufficiently studied. Understanding the magnitude of NbS impact is crucial for justifying their preference over non-NbS alternatives and, consequently, for securing public investment. Via a meta-analysis, this paper aims to contribute to research and practice by providing a more systematic assessment of NbS effects, offering urban planners and decision-makers a robust justification for their incorporation in climate change adaptation, urban resilience, and enhanced liveability. The results of the meta-analytic model indicate that the effect of NbS is indeed positive. When assessing the impact on temperature and flood protection, there is a general positive effect across the studied NbS. However, when evaluating an average effect, the task appears to be more complex due to methodological issues and limitations. The need to increase the formalisation of how the impact of NbS is measured and reported also emerges as a result. Replicable protocols would positively impact the formalisation of the literature on the topic and positively affect the evidence-based support for the implementation of NbS by urban decision-makers.
- Integrating a hydrological model into regional water policies: co-creation of climate change dynamic adaptive policy pathways for water resources in southern PortugalPublication . Dias, Luís Filipe; Aparício, Bruno A.; Nunes, João Pedro; Morais, Inês; Fonseca, Ana Lúcia; Pastor, Amandine V; Santos, FilipeIrrigation is essential for a large part of Mediterranean agricultural systems, but scarce resources may cause conflicts between agricultural and domestic uses. These conflicts might be exacerbated by climate change, which could bring a drier climate and thus increase irrigation water demands while lowering supplies. These issues were addressed when designing a climate change adaptation plan for water resources in the Algarve region (southern Portugal), which was co-created between hydrologists and local stakeholders and policy-makers, by using the Dynamic Adaptive Policy Pathways (DAPP) approach to synthetize and communicate the results from hydrological modelling of future scenarios. The evolution of water availability and irrigation demands for key water assets in Algarve (southern Portugal) were simulated until 2100 for climate scenarios RCP4.5 and RCP8.5, using a modified version of Thornthwaite-Mather. The results show an increase in water stress, mainly in the RCP8.5 scenario. The results and need for adaptation were discussed with local and regional decision-makers and other stakeholders, and a set of adaptation measures was agreed upon. The discussed adaptation measures were then modelled and integrated the design of tailor-made DAPP. Finally, decision-makers and stakeholders were presented with DAPP and selected the most suitable and political reliable adaptation pathway that tackles projected climate change impacts in water resources until the end of the 21 st century. Stakeholders showed a strong preference for incremental and distributed small-scale measures, including the promotion of water use efficiency and landscape water retention, to large-scale measures such as wastewater recycling or new dams. A decrease in irrigation water use for agriculture was not considered socially desirable. Desalination was considered too costly for irrigation in the short term but kept in reserve in case other measures fail to keep water supplies at an acceptable level.