Browsing by Issue Date, starting with "2021-06"
Now showing 1 - 10 of 17
Results Per Page
Sort Options
- Impact of Water-Repellent Products on the Moisture Transport Properties and Mould Susceptibility of External Thermal Insulation Composite SystemsPublication . Roncon, Renata; Borsoi, Giovanni; Parracha, João Luís; Flores-Colen, Inês; Veiga, Rosário; Nunes, LinaExternal Thermal Insulation Composite Systems (ETICS) are constructive solutions widely used to increase the thermal insulation in new and retrofitted buildings. However, these systems can present several anomalies due to their constant exposure to weathering agents and anthropic factors. Water is generally the major cause of degradation. Thus, the application of water-repellent products can minimize the appearance of anomalies and increase the durability of the systems. In this paper, acrylic-based and siloxane-based hydrophobic products were applied to ETICS, with the aim of assessing the compatibility, effectiveness, and durability of these products. The moisture transport properties and mould susceptibility were assessed through laboratory tests on untreated and treated specimens. The durability of the hydrophobic treatments was also evaluated through artificial aging tests (heat-cold and freeze-thaw cycles). Results show that the protection products generally decreased water absorption, slightly decreased the drying rate, and presented adequate water vapor permeability. After aging, the products still had reasonable effectiveness and, with one exception, improved the water vapor diffusion of the systems. Additionally, ETICS underwent an alteration in the finishing coat (possible modification of the porosity) due to the aging cycles. No clear linear correlation was found between the contact angle values and water absorption results, evidencing the influence of other factors related to the composition of the water-repellent products.
- Ant functional structure and diversity changes along a post-grazing succession in Mediterranean oak woodlandsPublication . Wendt, Clara Frasconi; Nunes, Alice; Köbel, Melanie; Verble, Robin; Matos, Paula; Boieiro, Mário; Branquinho, CristinaGrazing exclusion may be used to promote the recovery of disturbed ecosystems. A promising way for the evaluation of its effectiveness is through the monitoring of key biological groups, particularly those more responsive to disturbance and playing key roles in ecosystem functioning. Ants have been used as ecological indicators as they are abundant, diverse and sensitive to environmental changes. Here, we aimed to evaluate changes in ant taxonomic and functional structure and diversity, using functional groups, along a post-grazing succession in a Mediterranean oak woodland and to understand which environmental variables drive them. The post-grazing succession comprised a chronosequence of grazing excluded sites for 8, 12 and 18 years and a grazed control site. We found that ant species richness, functional structure and diversity increased with years since grazing exclusion: Generalist/Opportunist and the Hot Climate specialists increased in the 18 years grazing excluded site, while the Cryptic Species group increased in the 12 years grazing excluded site. Yet, their responses were not linear over time. Time since grazing exclusion and vegetation structure explained differences in ant taxonomic and functional structure and diversity. The Invasive/Exotic group dominated in all sites, except in the longest excluded site, where it occurred in the lowest proportion. The invasive Argentine ant dominated the grazed site, where it may have led to ant taxonomic and functional homogenization. Our results suggest that the time and changes in habitat structure may favour the recovery of ant biodiversity, although the presence of the invasive Argentine ant species may have slowed it down.
- Digitizing a sustainable futurePublication . Reisch, Lucia A.; Joppa, Lucas; Howson, Peter; Gil, Artur José Freire; Alevizou, Panayiota; Michaelidou, Nina; Appiah-Campbell, Ruby; Santarius, Tilman; Köhler, Susanne; Pizzol, Massimo; Schweizer, Pia-Johanna; Srinivasan, Dipti; Kaack, Lynn H.; Donti, Priya L.; Rolnick, DavidDigital technologies have a crucial role in facilitating transitions toward a sustainable future. Yet there remain challenges to overcome and pitfalls to avoid. This Voices asks: how do we leverage the digital transformation to successfully support a sustainability transition?
- Bioaccumulation and potential ecotoxicological effects of trace metals along a management intensity gradient in volcanic pasturelandsPublication . Parelho, Carolina Paula Furtado de Medeiros; Rodrigues, Armindo; Barreto, Maria do Carmo; Cruz, José Virgílio; Rasche, Frank; Silva, Luís; Garcia, PatríciaThe particularities of volcanic soils raise the need to better understand the link between soil agricultural management intensity and trace metal bioaccumulation. The Azores are a region characterized by volcanic soils, which were changed in different degrees according to the intensity of the agricultural practices. The main objective of this study was to assess the potential ecotoxicological effects of the trace metals present in volcanic pastureland soils along a gradient of management intensity (i.e., semi-natural, permanent and reseeded), using earthworms (Eisenia fetida) as biological indicators. For this purpose earthworms were exposed during 7, 14, 28 and 56 days to soils from the three types of pastures. At each exposure time, we quantified trace element bioaccumulation (As, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Rb, U, V and Zn) and the activities of superoxide dismutase and acetylcholinesterase in earthworm tissues. Overall, the results showed that the type of pastureland management significantly increased the soil contents in trace metals: V, Co, Ni and Zn in semi-natural pasturelands; As, Cd and Hg in reseeded pasturelands; and, Rb and U in both permanent and reseeded pasturelands. The soil physicochemical properties observed in the reseeded pastureland systems (higher electric conductivity values associated with a moderately acid pH value) modulated the metal bioavailability, from soil to biota, leading to a greater Hg bioaccumulation in earthworm tissues. The long-term exposure (56 days) of earthworms to reseeded pastureland soil was associated with adverse biological effects (intensification of AChE activity and decrease of SOD activity), encompassing key processes such as neurotransmission and antioxidant defence mechanisms in resident soil biota (earthworms). This study point towards the increased importance of semi-natural and permanent pastureland management, over the intensive management (reseeded pasturelands), in favour of more sustainable ecosystems.
- Mário Mesquita : primeiros avanços na crítica jornalísticaPublication . Luz, José Luís Brandão daO pendor memorialista do presente texto recupera alguns traços e tonalidades do ambiente que, nos anos 60 do século passado, envolvia os estudantes do então Liceu de Ponta Delgada e recupera ainda o que presumo terem sido os primeiros avanços de Mário Mesquita na atividade jornalística. Trata-se, pois, de uma forma de homenagem à sua dedicação ao jornalismo, que exerceu pela vida fora, com a elevação, a argúcia e a independência que estes começos, nos periódicos de Ponta Delgada, não desmerecem.
- The species–area relationship in ant ecologyPublication . Ohyama, Leo; Holt, Robert D.; Matthews, Thomas J.; Lucky, AndreaAIM: The positive relationship between species richness and area-the species-area relationship (SAR)-is a key principle in ecology. Previous studies show large variation in the SAR across taxa collectively indicating the necessity of a taxon-focused approach to accurately evaluate biodiversity scaling patterns. Ants are ideal for this given their global distribution and role in ecosystem functioning. Using data from insular ant communities, this study quantified and investigated various attributes of ant SARs and reviewed the SAR literature for ant faunas, world-wide, to identify specific areas for improvement. LOCATION: Islands around the world. TAXON: Ants (Hymenoptera: Formicidae). METHODS: We aggregated data on species richness and island characteristics from previous studies on ant SARs to evaluate effects of climate, biogeographic realm, and latitude on slope values from these studies. A multimodel inference approach was used to determine the form of the different SARs, and whether there were any differences between mainland and insular SARs. We also assessed differences between mainland and insular SAR slopes and intercepts. To seek a general slope coefficient for ants, we used a mixed-effect model. Finally, we tested for potential thresholds in the global insular SAR using piecewise regression models. RESULTS: There was a negative relationship between SAR slopes and precipitation in both mainland and insular SARs, while SAR slopes and intercept values were higher in mainland compared to insular systems. Strong evidence of thresholds emerged in the global insular SAR. Finally, a general slope of 0.16 was observed for insular systems, which is lower than found in previous studies. MAIN CONCLUSIONS: A taxon-focused approach proves to showcase unexpected patterns in the SAR. Ant diversity increases faster across area in mainland areas compared to true islands. The influences of climate and biogeographic realms on the ant SAR warrant deeper study. Our review highlights knowledge gaps in the ant SAR that also extend to other taxa, such as the effects of nonnative species on the SAR.
- The Field Guide app : Connecting island communities to local conservation through mobile interactionPublication . Sousa, Daniel; Rocha Silva, Alexandra Filipa; Rosário, Isabel Amorim do; Ashby, Simone; Arroz, Ana Moura; Piasentin, Flora Bonazzi; Gabriel, Rosalina; Matos, SóniaHere we present Field Guide, a mobile application (app) designed to connect communities to nature-rich environments, which play a crucial role in nature conservation efforts. The app aligns to a mode of science communication that seeks to establish direct contact between publics and specialised scientific communities, most commonly known as the ’ask a scientist’ approach. Field Guide uses a geolocation positioning system to offer users the opportunity to pose questions to scientists whilst exploring a nature conservation site. In this demo, we display the app as a mock-up presentation before its first use by children and teenagers during afield-trip to a nature trail later in 2021.
- Atmospheric iodine, selenium and caesium depositions in France : I. Spatial and seasonal variationsPublication . Roulier, Marine; Bueno, Maïté; Coppin, Frédéric; Nicolas, Manuel; Thiry, Yves; Rigal, François; Le Hécho, Isabelle; Pannier, FlorenceThe spatial distribution and seasonal variations of atmospheric iodine (I), selenium (Se) and caesium (Cs) depositions remain unclear and this precludes adequate inputs for biogeochemical models. We quantified total concentrations and fluxes of these elements in rainfalls from 27 monitoring sites in France with contrasted climatic conditions; monthly measurements were taken over one year (starting in 2016/09). Since speciation of I and Se can impact their behaviour in the environment, analysis of their inorganic compounds was also conducted. Our results showed that annual I concentrations in rainfall were much higher than those of Se and Cs (annual means = 1.56, 0.044 and 0.005 μg L-1, respectively). The annual iodine concentrations were highly positively correlated with those of marine elements (i.e. Na, Cl and Mg), involving higher I concentrations under oceanic climate than for transition, continental and mountainous ones. Furthermore, common patterns were found between Se concentrations and both marine and terrestrial components consistent with the various sources of Se in atmosphere. The association of Cs with two anthropogenic components (i.e. NH4+ and NO3-) used in agriculture supports the hypothesis of its terrestrial origin (i.e. from atmospheric dusts) in rainfall. We found higher rainfall concentrations of I during the warmest months for all climates. However, no specific seasonal trend occurred for Se and Cs. On annual average, rainfall contained mostly unidentified selenium compounds (inorganic Se proportions = 25-54%) and equal proportions of inorganic and unidentified I compounds. Concentrations of iodate were higher under oceanic climate consistent with an iodine marine-origin.
- Oil Pollution Affects the Central Metabolism of Keystone Vachellia (Acacia) TreesPublication . Ferrante, Marco; Dangol, Anuma; Didi-Cohen, Shoshana; Winters, Gidon; Tzin, Vered; Segoli, MichalVachellia (formerly Acacia) trees are native to arid environments in Africa and the Arabian Peninsula, where they often support the local animal and plant communities acting as keystone species. The aim of this study was to examine whether oil pollution affected the central metabolism of the native keystone trees Vachellia tortilis (Forssk.) and V. raddiana (Savi), as either adults or seedlings. The study was conducted in the Evrona Nature Reserve, a desert ecosystem in southern Israel where two major oil spills occurred in 1975 and in 2014. Leaf samples were collected to analyze the central metabolite profiles from oil-polluted and unpolluted adult trees and from Vachellia seedlings growing in oil-polluted and unpolluted soils in an outdoor setup. We found that oil pollution had a stronger effect on one-year-old seedlings than on adult trees, reducing the levels of amino acids, sugars, and organic acids. While adult trees are mildly affected by oil pollution, the effects on young seedlings can cause a long-term reduction in the population of these keystone desert trees, ultimately threatening this entire ecosystem.
- Niche overlap and species co-occurrence patterns in carabid communities of the northern Chinese steppesPublication . Tsafack, Noelline; Wang, Xinpu; Xie, Yingzhong; Fattorini, SimoneUnderstanding how species sort themselves into communities is essential to explain the mechanisms that maintain biodiversity. Important insights into potential mechanisms of coexistence may be obtained from observation of non-random patterns in community assembly. The spatial niche overlap (Pianka index) and co-occurrence (c-score) patterns in carabid species in three types of steppes (desert steppe, typical steppe, and meadow steppe) in China was investigated. Non randomness was tested using null models. Niche overlap values were significantly higher than expected by chance in the desert steppe, where vegetation cover is less abundant and less uniformly distributed, which possibly forces species to concentrate in certain places. In the typical and meadow steppes, results were influenced by the scale of the analysis. At a broad scale, niche separation was found as a result of species segregation among different sectors (habitats) within these steppes, but when the analysis was conducted at a finer scale, species appeared to be no more segregated than expected by chance. The high co-occurrence averages found in the meadow and typical steppes indicate that the distributions of the species found in a site may be negatively affected by the presence of other species, which suggests that some species tend to exclude (or reduce the abundance of) others. The very low c-score average observed in the desert steppe suggests that competition is not involved there. Thus, in more homogeneous landscapes (such as the typical and meadow steppes), competition might play some role in community structure, whereas spatial variation in the abundances of species is more driven by the uneven spatial distribution of vegetation in the landscape where productivity is lower and less uniformly distributed.