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- Relatório final do projeto PASTURCLIM - Possíveis impactes das alterações climáticas nas pastagens dos AçoresPublication . Elias, R. B.; Melo, Catarina; Wallon, Sophie; Maduro Dias, Cristiana; Borba, A.E.S.; Madruga, João; Borges, Paulo A. V.; Ferreira, Maria TeresaO efeito de estufa é um fenómeno natural que permite que o planeta Terra tenha uma temperatura média adequada à existência de vida. Este efeito é causado pela presença na atmosfera de gases com efeito de estufa (GEE) (vapor de água, dióxido de carbono, metano, óxido nitroso e outros) que evitam que parte do calor emitido pela Terra seja perdido para o espaço. No entanto, a emissão excessiva, com origem humana, de alguns destes gases, principalmente dióxido de carbono, metano e óxido nitroso, aumentam o efeito de estufa, e causarão alterações na temperatura, precipitação e outros elementos climáticos nas próximas décadas ou séculos.
- Insights into Enteric Methane Emissions in Conventional and Organic Dairy Grazing Systems in Island RegionsPublication . Nunes, Hélder; Maduro Dias, cristiana; Abreu, Adriana; Silveira de Borba, Alfredo Emilio; Drumonde Melo, Catarina Alexandra; Failla, SebastianaABSTRACT: Pasture-based dairy systems are a cornerstone of agricultural practices in the Azores, contributing significantly to both the local economy and environmental sustainability. However, the environmental impact of these systems, particularly in terms of methane (CH4) emissions, remains a major challenge, especially given the need to balance productivity with ecological preservation. This study aimed to compare enteric methane emissions, floristic composition, productivity, and nutritional quality between conventional and organic pasture systems in the Azores. Data were collected from representative dairy farms over a 12-month period, with pasture samples analyzed monthly to assess floristic diversity, dry matter productivity, and nutritional quality (crude protein and digestibility). Methane emissions were estimated using the IPCC Tier 2 methodology, incorporating data on animal performance, diet composition, and energy intake to calculate CH4 emissions per cow per year. The results showed that organic pastures had greater floristic diversity (5.10 ± 0.25 species/m2) than conventional pastures (4.00 ± 0.23 species/m2). However, conventional systems exhibited higher dry matter productivity (22.85 g/m2 vs. 15.35 g/m2) and incorporated corn silage, which enhanced digestible energy and reduced methane emissions (81.33 kg CH4/cow/year) compared to organic systems (89.17 kg CH4/cow/year). Although organic pastures had higher crude protein content (20.65%), their lower digestibility contributed to higher methane emissions. This study underscores the trade-offs between environmental sustainability, pasture productivity, and methane mitigation in pasture-based dairy systems, highlighting the need for integrated management approaches that balance ecological and production goals.
- Sustainability of Island Pastures Under Global Warming: Impacts on Forage Productivity, Soil Fertility and Forage QualityPublication . Drumonde Melo, Catarina Alexandra; Wallon, Sophie; Maduro Dias, cristiana; Silveira de Borba, Alfredo Emilio; Madruga, João; Nunes, Hélder; Pires Bento da Silva Elias, Rui MiguelABSTRACT: The Azorean livestock system depends strongly on pasture-based feeding, making regional agriculture sensitive to global warming. This study assessed the effects of experimental warming on forage productivity, forage quality, and soil fertility in three pastures along an altitudinal gradient over two years (2020–2021). Open-top chambers were used to create warmer conditions, and soil and forage samples were analysed for chemical and mineral composition. Warming increased net forage productivity by 30% and 70% in the lower-altitude pasture in 2020 and 2021, respectively, and by 56% in the intermediate-altitude pasture in 2021. Responses at the highest altitude were weak or not significant. Effects on forage quality were seasonal. In winter and early spring, warming increased crude protein by 14–45% and ash by 4–13% in the lower- and intermediate-altitude pastures. Later in the season, warming was associated with higher fibre fractions, especially in the intermediate-altitude pasture, indicating faster plant maturation. Soil factors significantly structured forage quality, with phosphorus as the main driver. This study contributes to understanding how climate change may affect the sustainability of pasture-based livestock systems in island environments, supporting the development of adaptive management strategies to safeguard productivity, soil fertility, and ecosystem resilience.