http://hdl.handle.net/10174/148 2026-08-01T16:27:58Z http://hdl.handle.net/10174/41670 Title: Promoting Landscape Heterogeneity in Silvopastoral Systems through Very High-Voltage Power Line Pylons: An Unconventional Approach Authors: P. Fernandes, Mariana; Matono, Paula; Pinto-Cruz, Carla; Almeida, Erika; Nunes, Alice; Belo, Anabela; Moreira, Francisco Abstract: Mediterranean silvopastoral systems (Montado in Portugal or Dehesa in Spain) are considered High Nature Value farmlands with sustainable and low-intensity human use that unite forestry and livestock production, being characterized by a habitat mosaic that combines natural and semi-natural grasslands, a tree layer with different densities of Quercus spp. (mainly Q. suber or Q. rotundifolia, or both) and singular landscape elements (e.g. small shrublands, small rocky outcrops, temporary ponds, and watercourses with riparian galleries). Singular landscape elements are crucial to ecosystem services' functioning by providing habitat heterogeneity and connectivity that support species' life cycles and sustain ecological networks. As the management of Mediterranean silvopastoral systems intensifies, with overgrazing threatening the maintenance of singular landscape elements, these systems' functionality and high biodiversity are compromised. Designing restoration solutions tailored to the farmland context could be a helpful strategy to offset the landscape simplification and multifunctionality loss of the silvopastoral systems. Very high-voltage power line pylons, widespread also trough farmlands, can be handled as an artificial singular landscape element by using their base surface to promote native vegetation and provide an opportunity to restore landscape heterogeneity and connectivity to plants and some fauna. The area under very high-voltage pylons is negligible for agricultural or grazing uses and challenging to access by machinery, being frequently left unmanaged and, therefore, available to apply restoration solutions without compromising the landowner's productivity and profitability. Our study tested the hypothesis that vegetation under very high-voltage pylons can be restored to create elements of heterogeneity in grazing systems. We tested two restoration solutions: a passive one by grazing exclusion and an active one that combines grazing exclusion with a native seed mix application. We aimed to assess these restoration solutions' effectiveness in recovering Mediterranean vegetation patches under very high-voltage pylons and their effects on the plant community's composition, diversity and vertical structure. The study, carried out over five years, took place in southern Portugal under 15 very high-voltage pylons (plots of 48m2) distributed in Mediterranean silvopastoral systems grazed by cattle. We fenced 10 plots in autumn 2017: five to Passive Restoration by excluding cattle grazing and promoting natural regeneration, and five to Active Restoration by sowing a seed mix of herbaceous and shrub native species. We also established five plots as control (No Intervention). We surveyed the vegetation and assessed the plants' abundance and the mean vegetation height before (spring 2017) and after the intervention (spring 2018-2021). We evaluated the species richness, Shannon index diversity, vertical structure (vegetation mean height) and the dissimilarity of the community composition between the pre- and post-intervention periods. The restoration solutions increased plant communities' heterogeneity at the landscape level by establishing plant communities underneath very high-voltage pylons that contrast in plant composition and vegetation vertical structure with the surrounding grassland. Although more time-consuming and expensive, the active restoration solution increased species richness and maintained species diversity locally. In contrast, the passive restoration solution, at the local scale, maintained species richness but decreased species diversity. The bases of very high-voltage pylons can effectively be used to create singular landscape elements in grazed systems and may serve as stepping stones between remnants of natural vegetation. Using the bases of very high-voltage pylons to promote native vegetation and increase landscape heterogeneity can be a complementary strategy to offset the adverse effects of overgrazing in silvopastoral systems and a new approach to bring natural elements into agricultural landscapes, as shown in our pilot essay. 2025-05-27T23:00:00Z http://hdl.handle.net/10174/41020 Title: Fluid Dynamics of the São Jorge Channel, Azores Plateau First results of RV Meteor expedition M186 Authors: Schmidt, C; Zitoun, R.; et al. Abstract: Young oceanic plateaus are important for fluid exchange between the lithosphere and the ocean. Increased heat fluxes can lead to a large-scale upwelling of fluids that play a role in global elemental cycles. In addition, variations in fluid chemistries can potentially influence the biomass and species compositions of microbial and benthic communities in sediments exposed to subsurface fluid flow. Yet, the present understanding of these young oceanic plateaus in terms of their fluid dynamics and their biogeochemical local and global impacts is limited. The goal of RV Meteor Expedition M186 in December 2022 was to investigate how subsurface fluids on the young Azores Plateau, Central North Atlantic, vary with respect to their flow rates, chemical compositions, and the prevalent on microbial and benthic communities at and below the seafloor. First data from the São Jorge Channel (Azores Plateau) show that fluid dynamics here are diffuse rather than focused, and that fluid chemical compositions nonetheless show strong local variations, over a small spatial scale of 65 km2, that could be related to differences in fluid origins and fluid flow paths. However, the connection of fluid conduits, heat flow data and biogeochemical data as well as their relation to faults visible in seismic data are rather complex. Our first results thus indicate that diffuse fluid flow on young oceanic plateaus is highly heterogeneous despite occurring over large sediment-covered areas. Thus, the role of fluids at young oceanic plateaus as an important intermediate between the lithosphere and the ocean cannot be generalized over large spatial and possibly temporal scales. 2023-03-31T23:00:00Z http://hdl.handle.net/10174/40075 Title: Bivalve gut microbiome responses to sediment characteristics and anthropogenic activities in Cerastoderma edule (Linnaeus, 1758) Authors: Neves, Joana; Mil-Homens, Mário; Martins, Marta; Adão, Helena; Arteaga, Jorge Abstract: Estuaries are highly dynamic ecosystems that are influenced by fluctuating environmental conditions and sediment-associated contamination. These factors can significantly affect microbiomes associated with their hosts. In this study, we investigated the gut microbiome of the bivalve Cerastoderma edule by integrating bacteria (16S rRNA) and fungal (ITS) diversity data with sediment physicochemical parameters across three estuarine sites subjected to varying degrees of anthropogenic pressure. Sampling was conducted in the Sado Estuary (Portugal), a warm-temperate, mesotidal system. The selected areas, Tróia (TR), Gâmbia (GAM), and Navigator (NAV), represent contrasting environmental settings, from low-contaminated (TR) to more impacted zones influenced by industrial and aquaculture activities (GAM and NAV). Microbial diversity and composition were assessed on a seasonal basis using next-generation sequencing and multivariate analyses. Alpha diversity metrics revealed differences in bacterial communities between sites and seasons, whereas fungal diversity remained relatively stable across locations. This suggests that gut-associated fungi are more resilient to environmental pressures, although specific compositional shifts were observed in the impacted areas, with some taxa showing correlations with trace metal concentrations. Principal Component Analysis (PCA) indicated strong associations between gut microbial composition and sediment parameters, including organic matter, salinity, and trace metals. In particular, the bacterial communities exhibited strong responses to trace metals, such as Hg, Zn, and Pb. Functional inference (FAPROTAX) highlighted the microbial involvement in nitrogen, sulfur, and carbon cycling, indicating potential adaptive responses to contamination. Together, these findings support the utility of the C. edule gut microbiome as a sensitive indicator of estuarine environmental status and host–environment interactions. Moreover, they underscored the importance of including both bacterial and fungal components to obtain a more holistic understanding of microbiome-mediated ecosystem functions. 2025-11-19T00:00:00Z http://hdl.handle.net/10174/37704 Title: Life Águeda – Restoring River Connectivity For Migratory Fish In The Vouga River Basin Authors: Pedro, S.; Alexandre, CM; Mateus, CS; Quintella, BR; Boavida-Portugal, J; Lança, M.J.; Belo, AF; Pereira, E; Rato, AS; Oliveira, IC; Silva, S; Almeida, P.R. Abstract: Presentation of the results of the work carried out on this subject in the Vouga River basin 2024-03-31T23:00:00Z